Microglia and tumor (excluding TNF)

1. Aoki K, Uchihara T, Sanjo N, Nakamura A, Ikeda K, Tsuchiya K, Wakayama Y (2003) Increased expression of neuronal apolipoprotein E in human brain with cerebral infarction. Stroke 34:875-880
   Abstract: BACKGROUND AND PURPOSE: Cellular origin of apolipoprotein E (ApoE) in the human brain and its roles in physiological and pathological conditions remain to be clarified. METHODS: Immunolocalization of ApoE was investigated in a series of autopsied human brains with or without infarction. ApoE expression was also estimated on immunoblot on protein extracts from autopsied brains and a cultured neuroblastoma cell line of human origin (GOTO) subjected to an oxidative stress induced by exposure to hydrogen peroxide (0.2 mmol/L). RESULTS: In addition to astrocytes and Microglia, neurons and degenerated axons in and around the ischemic foci contained ApoE-like immunoreactivity, which was more intense in recent ischemic foci. Immunoblot demonstrated an increase in expression of ApoE in brain extracts from ischemic lesion, and this increase was also pronounced in the cultured neuroblastoma cell line after the stress. CONCLUSIONS: Accumulation of ApoE in neurons in and around ischemic foci of the human brain is related to an increase in ApoE synthesis in neurons, as seen in cultured neuronal cells after oxidative stress. Intrinsic regenerative activity of neuron in reaction to external insults may be related to this increase in ApoE of neuronal origin

2. Castilla EA, Prayson RA, Kanner AA, Rybicki LA, Tubbs RR, Vogelbaum MA, Barnett GH (2003) Cyclooxygenase-2 in oligodendroglial neoplasms. Cancer 98:1465-1472
   Abstract: BACKGROUND: Although increased expression of cyclooxygenase-2 (COX-2) has been described in association with a variety of neoplasms, including tumors of astrocytic derivation, limited data are available on COX-2 expression in oligodendrogliomas. METHODS: The current study retrospectively reviewed 53 oligodendrogliomas and 7 oligodendroglioma-predominant oligoastrocytomas (mixed gliomas) for COX-2 expression and MIB-1 proliferative index (by immunohistochemistry) and for chromosome 1p status (by fluorescence in situ hybridization). RESULTS: Patients included 35 males and 25 females, with a mean age of 41 years (range, 12-73 years) at the time of surgery. Forty-four tumor specimens were classified as World Health Organization (WHO) Grade II neoplasms and 16 as WHO Grade III tumors. MIB-1 labeling indices (marker of cell proliferation) ranged from 0 to 22.3 (mean 4.5). Twenty-eight tumor specimens demonstrated allelic loss on chromosome 1p. Positive staining was observed in 17 tumor specimens with COX-2 antibody. COX-2-positive tumor specimens were also evaluated with CD68 (macrophage/Microglial cell marker) by coimmunolabeling to confirm that the observed COX-2 immunostaining was not due to immunoreactive macrophages or Microglial cells. COX-2 expression, lack of allelic loss at chromosome 1p, and high proliferation indices were associated with decreased survival (P = 0.002, P = 0.009, and P = 0.015, respectively). No correlation with outcome was found with patient gender, age at diagnosis, or histologic grade. CONCLUSIONS: Chromosome 1p, COX-2 immunoreactivity, and MIB-1 labeling indices correlated with outcome and were associated with decreased survival. There was not a one-to-one correspondence between COX-2 immunoreactivity and lack of allelic loss at chromosome 1p. Tumors with expression of COX-2 by immunohistochemistry may, in theory, benefit from treatment with therapeutic agents that inhibit COX-2

3. Das P, Estephan R, Banerjee P (2003) Apoptosis is associated with an inhibition of aminophospholipid translocase (APTL) in CNS-derived HN2-5 and HOG cells and phosphatidylserine is a recognition molecule in Microglial uptake of the apoptotic HN2-5 cells. Life Sci. 72:2617-2627
   Abstract: A balance of the activities of multiple enzymes maintains the typical asymmetry of plasma membrane lipids in healthy cells. Such enzyme activities are (a) the aminophopholipid translocase (APTL) (a lipid-selective P-type ATPase that catalyzes inward movement of aminophospholipids), (b) the scramblase (a calcium-dependent and ATP-independent enzyme that catalyzes both inward and outward movement of lipids), (c) the floppase (an ATP-dependent enzyme that catalyzes only outward movement of lipids). Activation or inhibition of any one of these enzymes would lead to a loss in this asymmetry. Apoptosis-associated externalization of phophatidylserine has been reported for many different cell-types, but the exact mechanism involved in this loss of membrane asymmetry has not been identified yet. In this report we demonstrate concurrence of APTL inhibition, caspase-3 activation and apoptosis in CNS-derived HN2-5 and HOG cells. Additionally, we provide data to demonstrate that the phagocytosis of apoptotic, CNS-derived HN2-5 cells by the Microglial cells requires recognition through phosphatidylserine (PS). Thus the enzyme aminopholipid translocase is inhibited during apoptosis of CNS-derived cells and this alone could account for the loss of plasma membrane lipid-asymmetry observed in these cells

4. Deininger MH, Weinschenk T, Meyermann R, Schluesener HJ (2003) The allograft inflammatory factor-1 in Creutzfeldt-Jakob disease brains. Neuropathol.Appl.Neurobiol. 29:389-399
   Abstract: The allograft inflammatory factor-1 (AIF-1) is a 17-kDa IFN-gamma inducible Ca(2+)-binding EF-hand protein that is encoded within the HLA class III genomic region and is involved in immune dysfunction and smooth muscle cell activation. We used immunohistochemistry double labelling experiments to analyse the spatial distribution and cell-type-specific localization of AIF-1 in the brains of patients who died as a result of sporadic Creutzfeldt-Jakob disease (CJD) and neuropathologically unaltered controls. Significantly more AIF-1 immunoreactive macrophages/Microglial cells and, interestingly, neurones were observed in CJD patients compared to controls. Western blotting confirmed more prominent AIF-1 immunoreactive bands of approximately 50 kDa in four CJD patients compared to three controls. Chaotropic SDS-PAGE of the recombinant AIF-1 resulted in almost complete reduction of the 50 kDa band and mass spectrometry revealed only AIF-1-specific tryptic protein fragments suggesting that trimerized AIF-1 is the predominant form in vivo. Finally, we analysed mechanisms of neuronal AIF-1 induction. Following H2O2 challenge, a model of general cell stress, we observed the gradual induction of AIF-1 and, more interestingly, release to the supernatant of SKNSH neurones. Parallel reverse transcriptase polymerase chain reaction and sequencing was used to confirm AIF-1 mRNA expression

5. Fiano V, Ghimenti C, Schiffer D (2003) Expression of cyclins, cyclin-dependent kinases and cyclin-dependent kinase inhibitors in oligodendrogliomas in humans. Neurosci.Lett. 347:111-115
   Abstract: Cyclins are regulatory proteins of the cell cycle which bind and activate kinases. In gliomas, contrary to many malignancies, cyclin D1 is rarely amplified, but together with other cyclins, it increases with anaplasia. In a series of 23 surgical biopsies of grade II and III oligodendroglioma, cyclin D1, E, A, B1, CDK4-6, CDK2, Cdc2 and p27/Kip.1 have been studied by immunohistochemistry and Western blot. Cyclin D1 and A increased with anaplasia, showing a linear correlation with MIB.1 labeling index and an inverse correlation with p27/Kip.1 expression. Cyclin E and B1 and kinases were almost only expressed in grade III tumors. Normal oligodendrocytes and Microglia cells of the cortex and white matter showed a clear positivity for cyclin D1, but not for other cyclins or kinases

6. Flannery T, Gibson D, Mirakhur M, McQuaid S, Greenan C, Trimble A, Walker B, McCormick D, Johnston PG (2003) The clinical significance of cathepsin S expression in human astrocytomas. Am.J.Pathol. 163:175-182
   Abstract: Early local invasion by astrocytoma cells results in tumor recurrence even after apparent total surgical resection, leading to the poor prognosis associated with malignant astrocytomas. Proteolytic enzymes have been implicated in facilitating tumor cell invasion and the current study was designed to characterize the expression of the cysteine proteinase cathepsin S (CatS) in astrocytomas and examine its potential role in invasion. Immunohistochemical analysis of biopsies demonstrated that CatS was expressed in astrocytoma cells but absent from normal astrocytes, oligodendrocytes, neurones and endothelial cells. Microglial cells and macrophages were also positive. Assays of specific activity in 59 astrocytoma biopsies confirmed CatS expression and in addition demonstrated that the highest levels of activity were expressed in grade IV tumors. CatS activity was also present in astrocytoma cells in vitro and the extracellular levels of activity were highest in cultures derived from grade IV tumors. In vitro invasion assays were carried out using the U251MG cell line and the invasion rate was reduced by up to 61% in the presence of the selective CatS inhibitor 4-Morpholineurea-Leu-HomoPhe-vinylsulphone. We conclude that CatS expression is up-regulated in astrocytoma cells and provide evidence for a potential role for CatS in invasion

7. Giri RK, Selvaraj SK, Kalra VK (2003) Amyloid peptide-induced cytokine and chemokine expression in THP-1 monocytes is blocked by small inhibitory RNA duplexes for early growth response-1 messenger RNA. J.Immunol. 170:5281-5294
   Abstract: In Alzheimer's disease (AD) one finds increased deposition of A beta and also an increased presence of monocytes/macrophages in the vessel wall and activated Microglial cells in the brain. AD patients show increased levels of proinflammatory cytokines by activated Microglia. Here we used a human monocytic THP-1 cell line as a model for Microglia to delineate the cellular signaling mechanism involved in amyloid peptides (A beta(1-40) and A beta(1-42))-induced expression of inflammatory cytokines and chemokines. We observed that A beta peptides at physiological concentrations (125 nM) increased mRNA expression of cytokines (TNF-alpha, and IL-1 beta) and chemokines (monocyte chemoattractant protein-1 (MCP-1), IL-8, and macrophage inflammatory protein-1 beta (MIP-1 beta)). The cellular signaling involved activation of c-Raf, extracellular signal-regulated kinase-1 (ERK-1)/ERK-2, and c-Jun N-terminal kinase, but not p38 mitogen-activated protein kinase. This is further supported by the data showing that A beta causes phosphorylation of ERK-1/ERK-2, which, in turn, activates Elk-1. Furthermore, A beta mediated a time-dependent increase in DNA binding activity of early growth response-1 (Egr-1) and AP-1, but not of NF-kappa B and CREB. Moreover, A beta-induced Egr-1 DNA binding activity was reduced >60% in THP-1 cells transfected with small interfering RNA duplexes for Egr-1 mRNA. We show that A beta-induced expression of TNF-alpha, IL-1 beta, MCP-1, IL-8, and MIP-1 beta was abrogated in Egr-1 small inhibitory RNA-transfected cells. Our results indicate that A beta-induced expression of cytokines (TNF-alpha and IL-1 beta) and chemokines (MCP-1, IL-8, and MIP-1 beta) in THP-1 monocytes involves activation of ERK-1/ERK-2 and downstream activation of Egr-1. The inhibition of Egr-1 by Egr-1 small inhibitory RNA may represent a potential therapeutic target to ameliorate the inflammation and progression of AD

8. Grant R, Kapoor V (2003) Inhibition of indoleamine 2,3-dioxygenase activity in IFN-gamma stimulated astroglioma cells decreases intracellular NAD levels. Biochem.Pharmacol. 66:1033-1036
   Abstract: Astroglia provide essential metabolic and neurotropic support to cells within the CNS and participate in the cellular immune response with Microglia/macrophages following activation by the pro-inflammatory cytokine IFN-gamma. Activation of glial cells results in local oxidative stress and induction of a number of proteins including the enzyme indoleamine 2,3-dioxygenase (IDO). As a rate-limiting enzyme, IDO regulates tryptophan catabolism via the kynurenine pathway producing a series of metabolic precursors (some of which are neurotoxic) before complete oxidation to the essential pyridine nucleotide NAD. Inhibition of this pathway may therefore prove therapeutic in neuroinflammatory disease by reducing production of cell toxins. However, kynurenine metabolism may also be cytoprotective through de novo synthesis of cellular NAD levels. We investigated the hypothesis that IDO activity is directly involved in maintenance of intracellular [NAD] in activated astroglial cells through control of de novo synthesis. Exposure to IFN-gamma increased IDO activity from 7+/-1 nmol to 129+/-11 nmol kynurenine/hr/mg protein. Inhibition of IDO activity with either 6-chloro-D-tryptophan (competitive inhibition), or 3-ethoxy beta-carboline (non-competitive inhibition) resulted in a dose-dependent decrease in IDO activity that correlated directly with decreasing [NAD] (R(2)=0.92 and 0.81, respectively). These results support the hypothesis that one important consequence of increasing IDO activity in astroglial cells during inflammation is to maintain NAD levels through de novo synthesis from tryptophan. Inhibition of kynurenine pathway metabolism under these conditions may significantly decrease cell viability and CNS functions unless alternate precursors for NAD synthesis are available

9. Kang JQ, Chong ZZ, Maiese K (2003) Critical role for Akt1 in the modulation of apoptotic phosphatidylserine exposure and Microglial activation. Mol.Pharmacol. 64:557-569
   Abstract: Biological targets for neurodegenerative disease that focus on the intrinsic maintenance of cellular integrity and the extrinsic prevention of phagocytic cellular disposal offer the greatest promise for therapeutic intervention. Protein kinase B (Akt1), a serine-threonine kinase closely involved in cell growth and survival, offers a strong potential to address both intrinsic and extrinsic mechanisms of neuronal injury. We demonstrate that overexpression of a constitutively active form of Akt1 (myristoylated Akt1) in differentiated SH-SY5Y neuronal cells provides intrinsic cellular protection against apoptotic genomic DNA destruction and membrane phosphatidylserine (PS) exposure. Transfection of SH-SY5Y cells with a plasmid encoding a kinase-deficient dominant-negative Akt1 eliminates cytoprotection, suggesting that activation of Akt1 is necessary and sufficient to prevent apoptotic destruction. Apoptotic neuronal membrane PS exposure provides a unique pathway for Akt1 to offer extrinsic cellular protection and block Microglial activation, because independent cotreatment with an anti-PS receptor neutralizing antibody could also prevent Microglial proliferation. Akt1 maintains nuclear DNA integrity and membrane PS exposure through the specific inhibition of caspase 3-, 8-, and 9-like activities that were linked to mitochondrial membrane potential and cytochrome c release. Our work elucidates a novel capacity for Akt1 to maintain cellular integrity through a series of cysteine protease pathways and to uniquely regulate Microglial activation through the modulation of membrane PS residue externalization

10. Kang JQ, Chong ZZ, Maiese K (2003) Akt1 protects against inflammatory Microglial activation through maintenance of membrane asymmetry and modulation of cysteine protease activity. J.Neurosci.Res. 74:37-51
    Abstract: In several cell systems, protein kinase B (Akt1) can promote cell growth and development, but the "antiapoptotic" pathways of this kinase that may offer protection against cellular inflammatory demise have not been defined. Given that early cellular membrane phosphatidylserine exposure is a critical component of apoptosis, we investigated the role of Akt1 during neuronal apoptotic injury. By employing differentiated SH-SY5Y neuronal cells that overexpress a constitutively active form of Akt1 (myristoylated Akt1), free radical-induced cell injury was assessed through trypan blue dye exclusion, DNA fragmentation, membrane phosphatidylserine exposure, protein kinase B phosphorylation, cysteine protease activity, and mitochondrial membrane potential. Membrane phosphatidylserine exposure was both necessary and sufficient for Microglial activation, insofar as cotreatment with an antiphosphatidylserine receptor-neutralizing antibody could prevent Microglial activity following neuronal loss of membrane asymmetry. Furthermore, expression of myristoylated Akt1 not only prevented cell injury through the prevention of membrane phosphatidylserine exposure and genomic DNA fragmentation but also inhibited Microglial activation and proliferation that required the inhibition of caspase 9-, caspase 3-, and caspase 1-like activities linked to cytochrome c release. Interestingly, Akt1 modulation of membrane phosphatidylserine exposure was primarily through caspase 1 activity. Removal of Akt1 activity abolished neuronal protection, suggesting that Akt1 functions as a critical pathway for the maintenance of cellular integrity and the prevention of phagocytic cellular removal during neurodegenerative insults

11. Klegeris A, McGeer PL (2003) Toxicity of human monocytic THP-1 cells and Microglia toward SH-SY5Y neuroblastoma cells is reduced by inhibitors of 5-lipoxygenase and its activating protein FLAP. J.Leukoc.Biol. 73:369-378
    Abstract: To explore whether the proinflammatory products of the 5-lipoxygenase (5-LOX) pathway are involved in Microglia-mediated toxicity toward neuronal cells, we evaluated the effects of 5-LOX inhibitors using an in vitro assay system where human neuronal SH-SY5Y cells are exposed to toxic secretions from THP-1 monocytic cells or human Microglia. The specific 5-LOX inhibitors, REV 5901, zileuton, and 5-hydroxyeicosatetraenoic acid lactone; the nonselective LOX inhibitors, phenidone and dapsone; the dual 5-LOX/cyclooxygenase inhibitor, tepoxalin; and the selective inhibitor of the 5-LOX-activating protein (FLAP), MK-886, inhibited such toxicity. The toxicity was enhanced by the 5-LOX product leukotriene (LT)D(4) and reduced by the selective cysteinyl LT receptor (CysLT(1)) antagonist MK-571. The mRNAs for 5-LOX and FLAP were detected in THP-1 cells and human Microglia but not in SH-SY5Y cells. The data suggest that inhibition of proinflammatory LT production by 5-LOX inhibition could selectively reduce toxicity of Microglial cells and thus be beneficial in neuroinflammatory diseases

12. Lambert JC, Luedecking-Zimmer E, Merrot S, Hayes A, Thaker U, Desai P, Houzet A, Hermant X, Cottel D, Pritchard A, Iwatsubo T, Pasquier F, Frigard B, Conneally PM, Chartier-Harlin MC, DeKosky ST, Lendon C, Mann D, Kamboh MI, Amouyel P (2003) Association of 3'-UTR polymorphisms of the oxidised LDL receptor 1 (OLR1) gene with Alzheimer's disease. J.Med.Genet. 40:424-430
    Abstract: Although possession of the epsilon 4 allele of the apolipoprotein E gene appears to be an important biological marker for Alzheimer's disease (AD) susceptibility, strong evidence indicates that at least one additional risk gene exists on chromosome 12. Here, we describe an association of the 3'-UTR +1073 C/T polymorphism of the OLR1 (oxidised LDL receptor 1) on chromosome 12 with AD in French sporadic (589 cases and 663 controls) and American familial (230 affected sibs and 143 unaffected sibs) populations. The age and sex adjusted odds ratio between the CC+CT genotypes versus the TT genotypes was 1.56 (p=0.001) in the French sample and 1.92 (p=0.02) in the American sample. Furthermore, we have discovered a new T/A polymorphism two bases upstream of the +1073 C/T polymorphism. This +1071 T/A polymorphism was not associated with the disease, although it may weakly modulate the impact of the +1073 C/T polymorphism. Using 3'-UTR sequence probes, we have observed specific DNA protein binding with nuclear proteins from lymphocyte, astrocytoma, and neuroblastoma cell lines, but not from the Microglia cell line. This binding was modified by both the +1071 T/A and +1073 C/T polymorphisms. In addition, a trend was observed between the presence or absence of the +1073 C allele and the level of astrocytic activation in the brain of AD cases. However, Abeta(40), Abeta(42), Abeta total, and Tau loads or the level of Microglial cell activation were not modulated by the 3'-UTR OLR1 polymorphisms. Finally, we assessed the impact of these polymorphisms on the level of OLR1 expression in lymphocytes from AD cases compared with controls. The OLR1 expression was significantly lower in AD cases bearing the CC and CT genotypes compared with controls with the same genotypes. In conclusion, our data suggest that genetic variation in the OLR1 gene may modify the risk of AD

13. Lange-Dohna C, Zeitschel U, Gaunitz F, Perez-Polo JR, Bigl V, Rossner S (2003) Cloning and expression of the rat BACE1 promoter. J.Neurosci.Res. 73:73-80
    Abstract: The pathogenic processing of the amyloid precursor protein (APP) into beta-amyloid peptides, which give rise to beta-amyloid plaques in the brains of Alzheimer's disease patients, requires the enzymatic activity of the beta-site APP-cleaving enzyme 1 (BACE1). We report the cloning and sequence of a 1.5-kb DNA fragment upstream of the coding sequence of the rat BACE1 gene and the construction of a BACE1 promoter/luciferase reporter construct. The basal activity of this promoter construct was highest in neuronal cell lines such as BE(2)-C and PC12 and in the pancreatic cell line AR42J, somewhat lower in rat primary neurons, and astrocytic and Microglial cultures, very low in hepatocytes, and almost absent in fibroblasts and in the monocyte-macrophage cell line RAW264.7. The first 600 bp of this promoter are highly conserved among rat, mouse, and human, suggesting that this region contains regulatory elements that modulate BACE1 transcription. Indeed, this fragment contains several putative transcription factor binding sites such as MZF1, Sp1, four GATA-1 sites, and one YY1 site. Directed mutagenesis of GATA-1 elements led to altered luciferase expression, indicating that these sites are involved in the regulation of BACE1 transcription. Additionally, the analysis of promoter activities of deletion mutants suggests the presence of activators of BACE1 transcription between bases -514 to -753 and of suppressor elements between bases -754 and -1541. The BACE1 promoter sequence data and the constructs described here will be useful to identify factors that influence the expression of BACE1 in experimental paradigms in vitro

14. Luder CG, Lang C, Giraldo-Velasquez M, Algner M, Gerdes J, Gross U (2003) Toxoplasma gondii inhibits MHC class II expression in neural antigen-presenting cells by down-regulating the class II transactivator CIITA. J.Neuroimmunol. 134:12-24
    Abstract: Major histocompatibility complex (MHC) class II expression by Microglia and astrocytes is critical for CD4+-mediated immune responses within the central nervous system. Here, we demonstrate that the obligate intracellular parasite, Toxoplasma gondii, down-regulates activation-induced MHC class II expression in human-derived glioblastoma cells as well as in primary astrocytes and Microglia from cortices of rat fetuses. Down-regulation of MHC class II proteins was predominantly observed in parasite-positive, but not parasite-negative, host cells of T. gondii-infected cell cultures. MHC class II transcript levels induced by IFN-gamma alone or in combination with TNF-alpha were also clearly diminished after parasitic infection. Furthermore, T. gondii dose-dependently down-regulated the transcript levels of the class II transactivator CIITA. These results suggest that T. gondii partially evade CD4+-mediated intracerebral immune responses, a mechanism which may contribute to long-term persistence of the parasite within the CNS

15. Munch G, Gasic-Milenkovic J, Dukic-Stefanovic S, Kuhla B, Heinrich K, Riederer P, Huttunen HJ, Founds H, Sajithlal G (2003) Microglial activation induces cell death, inhibits neurite outgrowth and causes neurite retraction of differentiated neuroblastoma cells. Exp.Brain Res. 150:1-8
    Abstract: Activation of glial cells has been proposed to contribute to neuronal dysfunction and neuronal cell death in Alzheimer's disease. In this study, we attempt to determine some of the effects of secreted factors from activated murine N-11 Microglia on viability and morphology of neurons using the differentiated neuroblastoma cell line Neuro2a. Microglia were activated either by lipopolysaccharide (LPS), bacterial cell wall proteoglycans, or advanced glycation endproducts (AGEs), protein-bound sugar oxidation products. At high LPS or AGE concentrations, conditioned medium from Microglia caused neuronal cell death in a dose-dependent manner. At sublethal LPS or AGE concentrations, conditioned media inhibited retinoic acid-induced neurite outgrowth and stimulated retraction of already extended neurites. Among the many possible secreted factors, the contribution of NO or NO metabolites in the cytotoxicity of conditioned medium was investigated. Cell death and changes in neurite morphology were partly reduced when NO production was inhibited by nitric oxide synthase inhibitors. The results suggest that even in the absence of significant cell death, inflammatory processes, which are partly transmitted via NO metabolites, may affect intrinsic functions of neurons such as neurite extension that are essential components of neuronal morphology and thus may contribute to degenerative changes in Alzheimer's disease

16. Phuong LK, Allen C, Peng KW, Giannini C, Greiner S, TenEyck CJ, Mishra PK, Macura SI, Russell SJ, Galanis EC (2003) Use of a vaccine strain of measles virus genetically engineered to produce carcinoembryonic antigen as a novel therapeutic agent against glioblastoma multiforme. Cancer Res. 63:2462-2469
    Abstract: Despite the most aggressive medical and surgical treatments, glioblastoma multiforme remains incurable with a median survival of <1 year. We investigated the antitumor potential of a novel viral agent, an attenuated strain of measles virus (MV), derived from the Edmonston vaccine lineage, genetically engineered to produce carcinoembryonic antigen (CEA). CEA production as the virus replicates can serve as a marker of viral gene expression. Infection of a variety of glioblastoma cell lines including U87, U118, and U251 at MOIs 0.1, 1, and 10 resulted in significant cytopathic effect consisting of excessive syncycial formation and massive cell death at 72-96 h from infection. terminal deoxynucleotidyltransferase-mediated nick end labeling assays demonstrated the mechanism of cell death to be predominantly apoptotic. The efficacy of this approach in vivo was examined in BALB/c nude mice by using both s.c. and intracranial orthotopic U87 tumor models. In the s.c. U87 model, mice with established xenografts were treated with a total dose of 8 x 10(7) plaque forming units of MV-CEA, administered i.v. Mice treated with UV light inactivated MV, and untreated mice with established U87 tumors were used as controls. There was statistically significant regression of s.c. tumors (P < 0.001) and prolongation of survival (P = 0.007) in MV-CEA treated animals compared with the two control groups. In the intracranial orthotopic U87 model, there was significant regression of intracranial U87 tumors treated with intratumoral administration of MV-CEA at a total dose of 1.8 x 10(6) plaque forming units as assessed by magnetic resonance image (P = 0.002), and statistically significant prolongation of survival as compared with mice that received UV-inactivated virus and untreated mice (P = 0.02). Histological examination of brains of MV-CEA-treated animals revealed complete regression of the tumor with the presence of a residual glial scar and reactive changes, mainly presence of hemosiderin-laden macrophages. In addition, CEA levels in the peripheral blood in both the s.c. and orthotopic models increased before tumor regression, indicating viral gene expression, and returned to normal when the tumors regressed. Ifnar(ko) CD46 Ge transgenic mice, susceptible to MV infection, were used to assess central nervous system toxicity of MV-CEA. Intracranial administration of MV-CEA into the caudate nucleus of Ifnar(ko) CD46 Ge did not result in clinical neurotoxicity. Pathologic examination demonstrated limited Microglial infiltration surrounding the injection site. In summary, MV-CEA has potent antitumor activity against gliomas in vitro, as well as in both s.c. and orthotopic U87 animal models. Monitoring CEA levels in the serum can serve as a low-risk method of detecting viral gene expression during treatment, and could allow dose optimization and individualization of treatment

17. Platten M, Kretz A, Naumann U, Aulwurm S, Egashira K, Isenmann S, Weller M (2003) Monocyte chemoattractant protein-1 increases Microglial infiltration and aggressiveness of gliomas. Ann.Neurol. 54:388-392
    Abstract: Macrophages are thought to represent a first line of defense in anti-tumor immunity. Despite infiltration by Microglial cells, however, malignant gliomas are still highly aggressive tumors. We here identify monocyte chemoattractant protein-1 (MCP-1) as a critical chemoattractant for glioma-infiltrating Microglial cells. MCP-1-transfected rat CNS-1 gliomas were massively infiltrated by Microglial cells. Whereas MCP-1 did not promote the growth of CNS-1 cells in vitro, intracerebral CNS-1-transfected tumors grew more aggressively than control-transfected tumors. This provides the first functional evidence that MCP-1 recruits Microglial cells to gliomas and promotes their growth in vivo. Microglial cells may support rather than suppress glioma growth

18. Sasaki A, Horikoshi Y, Yokoo H, Nakazato Y, Yamaguchi H (2003) Antiserum against human glucose transporter 5 is highly specific for Microglia among cells of the mononuclear phagocyte system. Neurosci.Lett. 338:17-20
    Abstract: Human monocytes and a variety of tissue macrophages, including Microglia, were studied immunohistochemically to determine the expression of a novel Microglial marker, human glucose transporter 5 (hGLUT5), in these cells. The hGLUT5 was not expressed in most peripheral macrophages in the normal state, but weakly expressed in some foamy macrophages in atherosclerotic lesions. There was no hGLUT5 reactivity in blood monocytes. In the lesions of brain infarcts, foamy macrophages (predominantly monocyte-derived cells) in the ischemic core were mostly negative for hGLUT5, while activated and phagocytic Microglia in the transitional zone were consistently positive. The present study indicated that unlike other Microglial markers, hGLUT5 is rarely present in peripheral macrophages, and that hGLUT5 immunohistochemistry is useful in distinguishing Microglia-derived macrophages from monocyte-derived macrophages in acute necrotic lesions

19. Shimizu T, Sato K, Suzuki T, Tachibana K, Takeda K (2003) Induction of plasminogen activator inhibitor-2 is associated with suppression of invasive activity in TPA-mediated differentiation of human prostate cancer cells. Biochem.Biophys.Res.Commun. 309:267-271
    Abstract: We previously reported that 12-O-tetra-decanoylphorbol-13-acetate (TPA) induces Microglia-like differentiation and decreases malignancy in human prostate cancer TSU-Pr1 cells. To investigate the mechanism underlying differentiation and decrease of malignancy in TSU-Pr1 cells treated with TPA, we attempted to identify genes expressed differentially during the differentiation using differential display. We successfully detected plasminogen activator inhibitor type-2 (PAI-2) as one gene up-regulated by TPA treatment. The change in expression of PAI-2 by TPA was blocked by treatment with protein kinase C or mitogen-activated protein kinase inhibitors. We also found that secretion of PAI-2 protein was increased by TPA treatment. Moreover, we demonstrated that suppression of invasive activity of TSU-Pr1 cells by TPA treatment was blocked by co-treatment with anti-PAI-2 antibody. These results suggest that induction of PAI-2 is associated with suppression of invasive activity in TSU-Pr1 cells treated with TPA

20. Ando H, Saio M, Ohe N, Tamakawa N, Yu H, Nakayama T, Yoshimura S, Kaku Y, Iwama T, Shinoda J, Sakai N, Takami T (2002) B7.1 immunogene therapy effectively activates CD(4+) tumor-infiltrating lymphocytes in the central nervous system in comparison with B7.2 gene therapy. Int.J.Oncol. 20:807-812
    Abstract: The B7 gene utilizing immunogene therapy is one of the most common methods against tumor growth. However, there is no known study that investigated the difference between B7.1 and B7.2 with regard to B7 gene therapy in the central nervous system (CNS). Therefore, to clarify the difference, we established B7.1 or B7.2 gene transduced tumor cells originating from the murine T cell lymphoma cell line EL4 (EL4-B7.1 or EL4-B7.2). First, we observed the survival time after intracranial inoculation of parent (IC-wt) or genetically modified tumor cells. All mice in control groups (IC-wt or IC-mock) were dead within 16 days. While there was significant survival elongation in the B7.2 modified group (IC-B7.2, p=0.0002), all mice in this group were dead of tumor growth within 22 days. On the other hand, 60% of mice inoculated with EL4-B7.1 (IC-B7.1) survived more than 120 days (p<0.0001). Second, to shed light on the anti-tumor immune response in situ, we tried to analyze CD(4+) tumor-infiltrating T lymphocytes (CD(4+) TIL). To purify and analyze CD(4+) TIL, we had to deplete F4/80(+) Microglia because of the CD4 expression. In terms of activation marker expression in CD(4+) TIL, a small population was activated (CD25, 9.8%; CD69, 15.8%) in the control group (IC-wt). In contrast, the activation marker positive CD4+ TIL percentage both in IC-B7.1 (CD25, 25.1%; CD69, 40.1%) and IC-B7.2 (CD25, 16.2%; CD69, 28.3%) appeared to reflect the survival curve in both groups. These findings strongly suggest that, in the CNS, B7.1 gene therapy could effectively introduce CD(4+) TIL activation compared with B7.2 gene therapy. This is the first study clearly describing the difference between B7.1 gene therapy and B7.2 gene therapy in the CNS in terms of the activation status of CD(4+) TIL in situ

21. Badie B, Bartley B, Schartner J (2002) Differential expression of MHC class II and B7 costimulatory molecules by Microglia in rodent gliomas. J.Neuroimmunol. 133:39-45
    Abstract: To assess the immune function of Microglia and macrophages in brain tumors, the expression of MHC class II and B7 costimulatory molecules in three rodent glioma models was examined. Microglia and macrophages, which accounted for 5-12% of total cells, expressed B7.1 and MHC class II molecules in the C6 and 9L tumors, but not RG2 gliomas. Interestingly, the expression of B7.1 and MHC class II molecules by Microglia and macrophage was associated with an increase in the number of tumor-infiltrating lymphocytes in C6 and 9L tumors. B7.2 expression, which was present at low levels on Microglia and macrophages in normal brain, did not significantly change in tumors. Interestingly, the expression of all three surface antigens increased after Microglia were isolated from intracranial C6 tumors and cultured for a short period of time. We conclude that Microglia immune activity may be suppressed in gliomas and directly correlates to the immunogenecity of experimental brain tumors

22. Bate C, Rutherford S, Gravenor M, Reid S, Williams A (2002) Cyclo-oxygenase inhibitors protect against prion-induced neurotoxicity in vitro. Neuroreport 13:1933-1938
    Abstract: The mechanisms of neuronal loss during the course of the prion diseases are not fully understood. In this study, neurones treated with certain non-steroidal anti-inflammatory drugs (NSAIDs) were protected against the otherwise toxic effects of a peptide derived from the prion protein, or extracts containing infectious prions (PrP ). These NSAIDs inhibit the cyclo-oxygenase (cox) enzymes that metabolise arachidonic acid to prostaglandins (PG). Conversely, drugs that inhibited the metabolism of arachidonic acid to leucotrienes enhanced neurotoxicity. Studies with selective inhibitors highlighted the importance of the cox-1 isoform in prion-induced neurotoxicity. The cox-1 inhibitors also inhibited neuronal PGE production and protected both neuroblastoma cells and primary cortical neurones against prions. They also reduced Microglia-mediated killing of prion-treated neurones

23. Fukumitsu H, Takase-Yoden S, Furukawa S, Nemoto K, Ikeda T, Watanabe R (2002) Implantation of BDNF-producing packaging cells into brain. Cell Transplant. 11:459-464
    Abstract: In order to invent a screening system to check in vivo gene function and the efficiency of gene transfer mediated by a retroviral vector system, we established a novel packaging cell, PacC6/A8, that is transplantable to rat brains. The packaging cell is based on the gene of the neuropatogenic retrovirus, A8-V. For expression in the brain, a vector that expresses brain-derived neurotrophic factor (BDNF) tagged by c-Myc-His6 (LxA/bdmh) was constructed. After transfection of LxA/bdmh to PacC6/A8, a cloned cell line, PacC6/A8/bmh, was established. PacC6/A8/bmh cells stably produced pseudotyped retroviruses carrying LxA/bdmh. For a control, a retroviral vector that bears the gene that codes enhanced green fluorescent protein (EGFP) tagged by C-Mic-His6 was also created and used for the establishment of PacC6/A8/gfmh cells that produce pseudotyped retroviruses carrying LxA/gfmh. PacC6/A8/bmh and PacC6/A8/gfmh cells were injected to the brain of newborn rats. A tumor was formed in all the rats injected that did not exhibit any symptoms until 3-4 weeks after the injection. A histological study of the injected rats revealed that the transferred BDNF gene was expressed in the brain of rats injected with PacC6/A8/bmh cells, but not in rats with PacC6/A8/gfmh cells. Interestingly, many activated Microglia had migrated into the tumor induced by PacC6/A8/bmh cells, and expressed a high amount of BDNF

24. Johnston JB, Silva C, Power C (2002) Envelope gene-mediated neurovirulence in feline immunodeficiency virus infection: induction of matrix metalloproteinases and neuronal injury. J.Virol. 76:2622-2633
    Abstract: The release of neurotoxins by activated brain macrophages or Microglia is one mechanism proposed to contribute to the development of neurological disease following infection by lentiviruses, including feline immunodeficiency virus (FIV). Since molecular diversity in the lentiviral envelope gene influences the expression of host molecules implicated in neuronal injury, the role of the envelope sequence in FIV neuropathogenesis was investigated by using the neurovirulent FIV strain V1CSF, the nonneurovirulent strain Petaluma, and a chimera (FIVCh) containing the V1CSF envelope gene in a Petaluma background. All three viruses replicated in primary feline macrophages with equal efficiency, but conditioned medium from V

25. Klegeris A, McGeer PL (2002) Cyclooxygenase and 5-lipoxygenase inhibitors protect against mononuclear phagocyte neurotoxicity. Neurobiol.Aging 23:787-794
    Abstract: Neuroinflammation and oxidative stress are believed to be contributing factors to neurodegeneration in normal aging, as well as in age-related neurological disorders. Reactive Microglia are found in increased numbers in aging brain and are prominently associated with lesions in such age-related degenerative conditions as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). In vitro, stimulated Microglia or Microglial-like cells secrete neurotoxic materials and are generators of free radicals through their respiratory burst system. Agents that suppress Microglial activation are therefore candidates for neuroprotection. We have developed quantitative in vitro assays for measuring neurotoxicity of Microglia or other mononuclear phagocytes. Neuronal like SH-SY5Y cells are cultured in supernatants from activated cells of the human monocytic THP-1 line and their survival is followed. Respiratory burst is directly measured on the activated cells. We tested inhibitors of the cyclooxygenase (COX) or the 5-lipoxygenase (5-LOX) pathways as possible neuroprotective agents. The COX pathway generates inflammatory prostaglandins, while the 5-LOX pathway generates inflammatory leukotrienes. We found that inhibitors of both these pathways suppressed neurotoxicity in a dose-dependent fashion. They included the COX-1 inhibitor indomethacin; the COX-2 inhibitor NS-398; the mixed COX-1/COX-2 inhibitor ibuprofen; the nitric oxide (NO) derivatives of indomethacin, ibuprofen and flurbiprofen; the 5-LOX inhibitor REV 5901; and the 5-LOX activating protein (FLAP) inhibitor MK-886. The FLAP inhibitor also reduced respiratory burst activity in a more potent manner than indomethacin. Combinations of COX and 5-LOX inhibitors were more effective than single inhibitors. The data suggest that both COX inhibitors and 5-LOX inhibitors may be neuroprotective in vivo by suppressing toxic actions of Microglia/macrophages, and that combinations of the two might have greater therapeutic potential than single inhibitors of either class

26. Linden DR, El Fakahany EE (2002) Microglial derived nitric oxide decreases serotonin content in rat basophilic leukemia (RBL-2H3) cells. Eur.J.Pharmacol. 436:53-56
    Abstract: Nitric oxide (NO) and serotonin (5-hydroxytryptamine; 5-HT) are important neuromodulators that are involved in a myriad of biochemical reactions. In this work, we describe a novel model co-culture system to study the interactions between NO and 5-HT. NO derived from cytokine stimulated Bv2 Microglial cells depleted 5-HT from RBL-2H3 cells. Reduction of 5-HT content by NO derived from the NO donor S-nitroso-N-acetylpenicillamine (SNAP) was concentration-dependent, independent of intracellular Ca(2+) and inhibited by reduced glutathione (GSH). Collectively, these data indicate that this cell co-culture system is a viable model to study the mechanisms of interaction between nitrergic and serotonergic pathways

27. Liu H, Ng CE, Tang BL (2002) Nogo-A expression in mouse central nervous system neurons. Neurosci.Lett. 328:257-260
    Abstract: The longest central nervous system (CNS) specific isoform of the major myelin-associated inhibitor of neurite growth, Nogo-A, has previously been shown to be expressed largely in oligodendrocytes. Using an antibody raised against a recombinant fusion protein comprising amino acids 223-399 of Nogo-A, we show in this report that Nogo-A is also expressed in the cell body of a distinct set of CNS neurons. The antibody detects a single protein band of 220 kDa in rat brain lysate and neuroblastoma cell lysates. Immunofluorescent analyses reveal that Nogo-A is found largely in the endoplasmic reticulum of neuroblastoma cell lines SH-SY5Y and NIE-115. In the mouse CNS, Nogo-A can be found in specific subsets of neuronal cell bodies in addition to oligodendrocytes, but not glial fibrillary associated protein positive astrocytes or MAC-1 positive Microglia. Our results provide a conclusive demonstration of the expression of Nogo-A in CNS neurons, which suggests that Nogo-A may have distinct endogenous roles in neurons other than its known ability to inhibit neurite growth

28. Madigan MC, Penfold PL, King NJ, Billson FA, Conway RM (2002) Immunoglobulin superfamily expression in primary retinoblastoma and retinoblastoma cell lines. Oncol.Res. 13:103-111
    Abstract: Retinoblastoma (Rb) is the most common intraocular tumor of childhood. In this study we examined primary Rb specimens and Rb cell lines for the expression of immunoglobulin superfamily (IgSF) antigens: MHC class I and II (MHC-I and MHC-II), neural cell adhesion molecule (NCAM), intercellular adhesion molecule-1 (ICAM-1), and Thy-1, which play an important role in immune system and tumor cell interactions. MHC-I and-II, ICAM-1 (CD54), NCAM (CD56), and Thy-1 (CDw90) immunoreactivity was studied in eight primary Rb biopsy specimens using immunohistochemistry, three using immunoelectron microscopy, and six Rb cell lines using flow cytometry (FCM). Parenchymal and vascular-associated cells, phenotypically similar to retinal Microglia, strongly expressed MHC-II immunoreactivity and were distributed throughout primary Rb specimens. However, MHC-II expression on Rb cell lines was similar to nonspecific control levels. tumor cells in primary Rb specimens displayed high NCAM, moderate Thy-1, and low MHC-I and ICAM-1 immunolabeling. tumor vasculature expressed low to moderate MHC-I and ICAM-1 immunoreactivity and moderate Thy-1 immunoreactivity. NCAM was not detected on the vasculature of primary Rb specimens. Rb cell lines displayed variable expression of Thy-1, ICAM-1, and MHC-I. NCAM was highly expressed on five of six Rb cell lines. The high levels of constitutive NCAM immunoreactivity on Rb tumor cells confirm the neuroectodermal origins of this tumor. Additionally, the variable expression of Thy-1 may suggest separate neural lineages or differences in the maturational status ofsome Rb tumors. The presence of a population of infiltrating MHC-II-positive cells in primary Rb tumors has implications for immunomodulation of Rb growth

29. Mentlein R, Held-Feindt J (2002) Pleiotrophin, an angiogenic and mitogenic growth factor, is expressed in human gliomas. J.Neurochem. 83:747-753
    Abstract: Pleiotrophin (PTN) is a mitogenic/angiogenic, 15.3 kDa heparin-binding peptide that is found in embryonic or early postnatal, but rarely in adult, tissues. Since developmentally regulated factors often re-appear in malignant cells, we examined PTN expression in human glioma cell lines, cell cultures derived from solid gliomas and glioma sections. PTN mRNA or protein was detected by reverse transcriptase-polymerase chain reaction, immunohistochemistry, western blot or enzyme-linked immunoassay in all WHO III and IV grade gliomas and cells analyzed in vitro or in situ. One WHO II grade glioma investigated was PTN negative. In vitro, PTN was synthesized in perinuclear regions of glioma cells, secreted into the cultivation medium, but its production varied considerably between glioma cells cultivated from different solid gliomas or glioma cell lines. In situ, PTN expression was restricted to distinct parts/cells of the tumour. PTN did not influence the proliferation of glioma cells themselves, but stimulated [3H]thymidine incorporation into DNA of Microglial cells. Furthermore, in Boyden chamber assays, PTN showed a strong chemotactic effect on murine BV-2 Microglial cells. PTN is supposed to be a paracrine growth/angiogenic factor that is produced by gliomas and contributes to their malignancy by targeting endothelial and Microglial cells

30. Perini G, Della-Bianca V, Politi V, Della VG, Dal Pra I, Rossi F, Armato U (2002) Role of p75 neurotrophin receptor in the neurotoxicity by beta-amyloid peptides and synergistic effect of inflammatory cytokines. J.Exp.Med. 195:907-918
    Abstract: The neurodegenerative changes in Alzheimer's disease (AD) are elicited by the accumulation of beta-amyloid peptides (Abeta), which damage neurons either directly by interacting with components of the cell surface to trigger cell death signaling or indirectly by activating astrocytes and Microglia to produce inflammatory mediators. It has been recently proposed that the p75 neurotrophin receptor (p75(NTR)) is responsible for neuronal damage by interacting with Abeta. By using neuroblastoma cell clones lacking the expression of all neurotrophin receptors or engineered to express full-length or various truncated forms of p75(NTR), we could show that p75(NTR) is involved in the direct signaling of cell death by Abeta via the function of its death domain. This signaling leads to the activation of caspases-8 and -3, the production of reactive oxygen intermediates and the induction of an oxidative stress. We also found that the direct and indirect (inflammatory) mechanisms of neuronal damage by Abeta could act synergistically. In fact, TNF-alpha and IL-1beta, cytokines produced by Abeta-activated Microglia, could potentiate the neurotoxic action of Abeta mediated by p75(NTR) signaling. Together, our results indicate that neurons expressing p75(NTR), mostly if expressing also proinflammatory cytokine receptors, might be preferential targets of the cytotoxic action of Abeta in AD

31. Repovic P, Benveniste EN (2002) Prostaglandin E2 is a novel inducer of oncostatin-M expression in macrophages and Microglia. J.Neurosci. 22:5334-5343
    Abstract: Oncostatin-M (OSM), a pluripotent cytokine of the interleukin-6 (IL-6) family, is produced in a number of inflammatory conditions. Known sources of OSM include monocytes-macrophages and T-cells. Here we present Microglia, the resident macrophages of the brain, as a source of OSM in the CNS. In this context, we describe a novel inducer of OSM, prostaglandin E(2) (PGE(2)). PGE(2) induces OSM expression in Microglia, monocytes, and macrophages of human and murine origin. PGE(2) induction of OSM is mimicked by cholera toxin, an activator of stimulatory G (G(s))-proteins; by forskolin, an activator of adenylate cyclase; and by the cAMP analog, dibutyryl-cAMP. PGE(2) induction of OSM gene expression is inhibited by the adenylate cyclase inhibitor 2',5'-dideoxyadenosine, by the protein kinase A (PKA) inhibitor H-89, and by a dominant-negative PKA construct. These data indicate that PGE(2) signals via G(s)-protein-coupled receptor(s), adenylate cyclase, and PKA to induce OSM expression. Accordingly, other activators of cAMP signaling such as norepinephrine and PGE(1) induce OSM. The ability of PGE(2) to induce OSM expression was tested under more physiological conditions, using cocultures of astrocytes and monocytes. Treatment of the cocultures with IL-1beta or tumor necrosis factor-alpha (TNF-alpha) results in production of PGE(2) and OSM. PGE(2) produced in the cocultures is responsible for OSM induction, because pretreatment with indomethacin, an inhibitor of prostaglandin synthesis, as well as depletion of PGE(2), abrogate OSM expression induced by IL-1beta or TNF-alpha. These data suggest that in the CNS, OSM may be produced through collaboration of astrocytes and macrophages-Microglia

32. Seo JH, Rah JC, Choi SH, Shin JK, Min K, Kim HS, Park CH, Kim S, Kim EM, Lee SH, Lee S, Suh SW, Suh YH (2002) Alpha-synuclein regulates neuronal survival via Bcl-2 family expression and PI3/Akt kinase pathway. FASEB J. 16:1826-1828
    Abstract: Alpha-synuclein (alpha-SN) is a ubiquitous protein that is especially abundant in the brain and has been postulated to play a central role in the pathogenesis of Parkinson's disease, Alzheimer's disease, and other neurodegenerative disorders. However, little is known about the neuronal functions of alpha-SN and the molecular and cellular mechanisms underlying neuronal loss. Here, we show that alpha-SN plays dual roles of neuroprotection and neurotoxicity depending on its concentration or level of expression. At nanomolar concentrations, a-SN protected neurons against serum deprivation, oxidative stress, and excitotoxicity through the PI3/Akt signaling pathway, and its protective effect was increased by Bcl-2 overexpression. Conversely, at both low micromolar and overexpressed levels in the cell, alpha-SN resulted in cytotoxicity. This might be related to decreased Bcl-xL expression and increased bax expression, which is subsequently followed by cytochrome c release and caspase activation and also by Microglia-mediated inflammatory responses via the NFkappaB and mitogen-activated protein kinase pathways

33. Serhan CN, Hong S, Gronert K, Colgan SP, Devchand PR, Mirick G, Moussignac RL (2002) Resolvins: a family of bioactive products of omega-3 fatty acid transformation circuits initiated by aspirin treatment that counter proinflammation signals. J.Exp.Med. 196:1025-1037
    Abstract: Aspirin (ASA) is unique among current therapies because it acetylates cyclooxygenase (COX)-2 enabling the biosynthesis of R-containing precursors of endogenous antiinflammatory mediators. Here, we report that lipidomic analysis of exudates obtained in the resolution phase from mice treated with ASA and docosahexaenoic acid (DHA) (C22:6) produce a novel family of bioactive 17R-hydroxy-containing di- and tri-hydroxy-docosanoids termed resolvins. Murine brain treated with aspirin produced endogenous 17R-hydroxydocosahexaenoic acid as did human Microglial cells. Human COX-2 converted DHA to 13-hydroxy-DHA that switched with ASA to 17R-HDHA that also proved a major route in hypoxic endothelial cells. Human neutrophils transformed COX-2-ASA-derived 17R-hydroxy-DHA into two sets of novel di- and trihydroxy products; one initiated via oxygenation at carbon 7 and the other at carbon 4. These compounds inhibited (IC(50) approximately 50 pM) Microglial cell cytokine expression and in vivo dermal inflammation and peritonitis at ng doses, reducing 40-80% leukocytic exudates. These results indicate that exudates, vascular, leukocytes and neural cells treated with aspirin convert DHA to novel 17R-hydroxy series of docosanoids that are potent regulators. These biosynthetic pathways utilize omega-3 DHA and EPA during multicellular events in resolution to produce a family of protective compounds, i.e., resolvins, that enhance proresolution status

34. Tan J, Town T, Crawford F, Mori T, DelleDonne A, Crescentini R, Obregon D, Flavell RA, Mullan MJ (2002) Role of CD40 ligand in amyloidosis in transgenic Alzheimer's mice. Nat.Neurosci. 5:1288-1293
    Abstract: We have shown that interaction of CD40 with CD40L enables Microglial activation in response to amyloid-beta peptide (Abeta), which is associated with Alzheimer's disease (AD)-like neuronal tau hyperphosphorylation in vivo. Here we report that transgenic mice overproducing Abeta, but deficient in CD40L, showed decreased astrocytosis and microgliosis associated with diminished Abeta levels and beta-amyloid plaque load. Furthermore, in the PSAPP transgenic mouse model of AD, a depleting antibody against CD40L caused marked attenuation of Abeta/beta-amyloid pathology, which was associated with decreased amyloidogenic processing of amyloid precursor protein (APP) and increased circulating levels of Abeta. Conversely, in neuroblastoma cells overexpressing wild-type human APP, the CD40-CD40L interaction resulted in amyloidogenic APP processing. These findings suggest several possible mechanisms underlying mitigation of AD pathology in response to CD40L depletion, and validate the CD40-CD40L interaction as a target for therapeutic intervention in AD

35. Tanimukai S, Hasegawa H, Nakai M, Yagi K, Hirai M, Saito N, Taniguchi T, Terashima A, Yasuda M, Kawamata T, Tanaka C (2002) Nanomolar amyloid beta protein activates a specific PKC isoform mediating phosphorylation of MARCKS in Neuro2A cells. Neuroreport 13:549-553
    Abstract: Myristoylated alanine-rich C kinase substrate (MARCKS), a protein associated with cell growth, neurosecretion and macrophage activation, is activated by protein kinase C (PKC) phosphorylation. We reported that amyloid beta protein (Abeta) activated MARCKS through a tyrosine kinase and PKC-delta in rat cultured Microglia. Here we report that Abeta signaling pathway through a specific PKC isoform is involved in the phosphorylation of MARCKS in Neuro2A cells. Selective PKC inhibitors but not tyrosine kinase inhibitors significantly inhibited the phosphorylation of MARCKS induced by Abeta. Abeta selectively activated PKC-alpha among the four PKC isoforms localized in Neuro2A cells. PKC-alpha activated by Abeta directly phosphorylated a recombinant MARCKS in vitro, Translocation of PKC-alpha from the cytoplasm to the membrane and accumulation of phospho-MARCKS in the cytoplasm were induced by Abeta. These results suggest involvement of a phosphoinositide signaling system through PKC-alpha in the phosphorylation of MARCKS in neurons, an event which may be associated with mechanisms underlying neurotrophic and neurotoxic effects of Abeta

36. Traister RS, Lynch WP (2002) Reexamination of amphotropic murine leukemia virus neurovirulence: neural stem cell-mediated Microglial infection fails to induce acute neurodegeneration. Virology 293:262-272
    Abstract: The 4070A amphotropic murine leukemia virus (A-MuLV) has been variably reported to harbor neurovirulence determinants within its env gene. In this report we reexamined this issue by applying two approaches previously demonstrated to amplify murine leukemia virus neurovirulence. The first approach involved introducing the 4070A env gene into the background of Friend virus clone FB29 to enhance peripheral virus replication kinetics and central nervous system entry. The resulting chimeric virus, FrAmE, exhibited widespread vascular infection throughout the central nervous system (CNS); however, parenchymal infection was quite limited. Neither clinical neurological signs nor spongiform neurological changes accompanied FrAmE CNS infection. To overcome this CNS entry limitation, 4070A and FrAmE were delivered directly into the CNS via transplantation of infected C17.2 neural stem cells (NSCs). Significantly, NSC dissemination of either 4070A or FrAmE resulted in widespread, high-level amphotropic virus expression within the CNS parenchyma, including the infection of Microglia, the critical target required for inducing neurodegeneration. Despite the extensive CNS infection, no associated clinical neurological signs or acute neuropathological changes were observed. Interestingly, we observed the frequent appearance of circulating polytropic (MCF) virus in the serum of amphotropic virus-infected animals. However, neither peripheral inoculation of an amphotropic/MCF virus mixture nor transplantation of NSCs expressing both amphotropic and MCF viruses induced acute clinical neurological signs or spongiform neuropathology. Thus, the results generated in this study suggest that the 4070A env gene is not inherently neurovirulent. However, the frequent appearance of endogenous MCF viruses suggests the possibility that the interactions of amphotropic viruses with endogenous retroviral elements could contribute to the development of retrovirus-induced neurodegenerative disease

37. Warntges S, Friedrich B, Henke G, Duranton C, Lang PA, Waldegger S, Meyermann R, Kuhl D, Speckmann EJ, Obermuller N, Witzgall R, Mack AF, Wagner HJ, Wagner A, Broer S, Lang F (2002) Cerebral localization and regulation of the cell volume-sensitive serum- and glucocorticoid-dependent kinase SGK1. Pflugers Arch. 443:617-624
    Abstract: The serum- and glucocorticoid-dependent kinase SGK1 is regulated by alterations of cell volume, whereby cell shrinkage increases and cell swelling decreases the transcription, expression and activity of SGK1. The kinase is expressed in all human tissues studied including the brain. The present study was performed to localize the sites of SGK1 transcription in the brain, to elucidate the influence of the hydration status on SGK1 transcription and to explore the functional significance of altered SGK1 expression. Northern blot analysis of human brain showed SGK1 to be expressed in all cerebral structures examined: amygdala, caudate nucleus, corpus callosum, hippocampus, substantia nigra, subthalamic nucleus and thalamus. In situ hybridization and immunohistochemistry in the rat revealed increased expression of SGK1 in neurons of the hippocampal area CA3 after dehydration, compared with similar slices from brains of euvolaemic rats. Additionally, several oligodendrocytes, a few Microglial cells, but no astrocytes, were positive for SGK1. The abundance of SGK1 mRNA in the temporal lobe, including hippocampus, was increased by dehydration and SGK1 transcription in neuroblastoma cells was stimulated by an increase of extracellular osmolarity. Co-expression studies in Xenopus laevis oocytes revealed that SGK1 markedly increased the activity of the neuronal K+ channel Kv1.3. As activation of K+ channels modifies excitation of neuronal cells, SGK1 may participate in the regulation of neuronal excitability

38. Badie B, Schartner J, Prabakaran S, Paul J, Vorpahl J (2001) Expression of Fas ligand by Microglia: possible role in glioma immune evasion. J.Neuroimmunol. 120:19-24
    Abstract: The immune-privileged status of the central nervous system is thought to limit the application of immunotherapy for treatment of malignant brain tumors. Because the Fas pathway has been proposed to play a role in immune evasion, we examined the effect of tumor environment on the expression of Fas ligand (FasL) in a mouse glioma model. Immunoblotting revealed the expression of membrane-bound FasL to nearly double when murine G26 gliomas were propagated intracranially (IC) as compared to subcutaneously (SC). Further analysis by flow cytometry revealed Microglia, which were absent in the SC tumors, to account for half of the FasL expression in the IC tumors. Interestingly, when FasL activity was inhibited in IC tumors, the proportion of tumor-infiltrating leukocytes increased three-fold, reaching the same frequency as the SC tumors. These observations suggest that Microglia are a major source of FasL expression in brain tumors and possibly contribute to the local immunosuppressive milieu of malignant gliomas

39. Bate C, Reid S, Williams A (2001) Killing of prion-damaged neurones by Microglia. Neuroreport 12:2589-2594
    Abstract: The loss of neurones that occurs in the transmissible spongiform encephalopathies, or prion diseases, can be reproduced in vitro by incubating neuronal cultures with either peptides derived from the prion protein or with partially purified prion preparations. In the present studies, the extent of neuronal loss on exposure to these prions or prion peptides was increased by the addition of Microglia, a process that was dependent upon the number of Microglia added, the concentration of prions/peptides present and the degree of fibrillarity of the prion peptides. Microglia also killed scrapie-infected neuroblastoma cells expressing infectious PrP(SC). Microglia secreted low amounts of interleukin (IL)-6 when incubated with peptides alone but up to 10 times as much IL-6 when incubated with peptide-treated neurones, suggesting that Microglia recognise peptide-induced changes in neurones

40. Bu J, Akhtar N, Nishiyama A (2001) Transient expression of the NG2 proteoglycan by a subpopulation of activated macrophages in an excitotoxic hippocampal lesion. Glia 34:296-310
    Abstract: Cells that express the NG2 proteoglycan (NG2+ cells) constitute a large glial population in the normal mature rodent brain. They can differentiate into oligodendrocytes but are distinct from mature oligodendrocytes, astrocytes, Microglia, and neurons. Changes in NG2+ cells were examined in kainic acid-induced excitotoxic lesions of the hippocampus, and the relationship between NG2+ cells and reactive astrocytes and Microglia was investigated between 1 and 90 days after lesioning. Two types of reactive NG2+ cells with altered morphology and increased NG2 immunoreactivity were observed in the lesion. Early changes, consisting of an increase in NG2 immunoreactivity and the number of processes, were apparent 24 h after lesioning and persisted through 3 months. These cells were distinct from reactive astrocytes or activated Microglia/macrophages. A second type of reactive NG2+ cells appeared 2 weeks after injection, following an influx of macrophages. They had large, round cell bodies with short processes and expressed the Microglia/macrophage antigens OX42 and ED1. Single cells coexpressing NG2 and macrophage/Microglial antigens could be isolated from the lesion. The number of NG2+/OX42+ cells gradually declined and disappeared by 3 months after injection. They did not express glial fibrillary acidic protein or the alpha receptor for platelet-derived growth factor, indicating that they are distinct from astrocytes or oligodendrocyte progenitor cells. Cells that coexpressed NG2 and OX42 were never observed in hippocampal slice cultures treated with kainic acid, suggesting that NG2+/OX42+ cells are not derived from endogenous resident brain cells. These findings demonstrate that NG2 expression is transiently upregulated on activated macrophages/Microglia that appear during the chronic stage in an excitotoxic lesion in the adult CNS

41. Eales-Reynolds LJ, Laver H, Mojtahedi H (2001) Evidence for the expression of the EGF receptor on human monocytic cells. Cytokine 16:169-172
    Abstract: Several malignancies over-express the epidermal growth factor receptor, ligation of which results in cellular differentiation and multiplication. Mononuclear phagocytes secrete this cytokine and its receptor has been detected on Microglial cells. This communication describes the expression (and its regulation) of epidermal growth factor receptor (EGFR) on U937 cells. We have shown that a few are EGFR-positive, with expression being up regulated by interleukin 6 (IL-6). Also, when cultured in the presence of serum with the monoclonal anti-EGFR, ICR62, U937s showed a reduced growth rate. By contrast, ICR9 caused a significant increase in cellular proliferation. Both antibodies induced cycle arrest in late G(1)/S phase. When the cells were cultured in the absence of serum, low antibody concentration (10 microg/ml) showed an early inhibitory effect on cell proliferation. By contrast, at high antibody concentrations (50 micro/ml), ICR62 significantly increased the proliferation of U937 cells. We suggest that these results provide indirect evidence for an autocrine action of EGF on U937 cells

42. Elmlinger MW, Deininger MH, Schuett BS, Meyermann R, Duffner F, Grote EH, Ranke MB (2001) In vivo expression of insulin-like growth factor-binding protein-2 in human gliomas increases with the tumor grade. Endocrinology 142:1652-1658
    Abstract: Human central nervous system tumors and glioma cell lines highly express the insulin-like growth factor-binding protein (IGFBP)-2. As IGFBP-2 can affect tumor growth, we studied the relationship between IGFBP-2 expression and the malignancy of brain tumors in vivo. To do so, we investigated by immunohistochemistry the accumulation of IGFBP-1, -2, and -3 in 50 human gliomas classified by the WHO Malignancy Scale. Double labeling using anti-CD68 (monocytes/macrophages), antiglial fibrillary acidic protein, and anti-CD3 (T cells) antibodies was performed to further characterize the IGFBP-1, -2, and -3(+) cells. The expression of IGFBP messenger RNAs (mRNAs) was tested by RT-PCR in tumor samples from nine gliomas of different grades and in eight cell lines representing the cellular composition of human glioma. As controls, the accumulation of IGFBP-2 was investigated in normal brain and in the rat C6 glioblastoma model. IGFBP-1 and -3 accumulated in endothelial and macrophage/Microglial cells. IGFBP-2(+) macrophage/Microglial and glioma cells clustered in the immediate vicinity of focal necrosis of the human gliomas as well as of the rat C6 glioblastoma. The labeling score of IGFBP-1 accumulation in endothelial cells correlated negatively (P: = 0.0229), and that of IGFBP-2 accumulation in glioma cells correlated positively (P: < 0.0006) with the tumor grade of the gliomas. In addition, RT-PCR analysis confirmed mRNA expression of IGFBP-1, -2, and -3 by the gliomas and glial cells. Small amounts of IGFBP-1 and -3 mRNA, but high amounts of IGFBP-2 mRNA, were detectable in macrophage-like and glioma cell lines. The results suggest cell type-specific accumulation of IGFBP-1, -2, and -3 in human glial tumors of the brain. The increase in IGFBP-2 expression with this malignancy suggests a role of IGFBP-2 in the biology of human gliomas

43. Fischer FR, Luo Y, Luo M, Santambrogio L, Dorf ME (2001) RANTES-induced chemokine cascade in dendritic cells. J.Immunol. 167:1637-1643
    Abstract: Dendritic cells (DC) are the most potent APCs and the principal activators of naive T cells. We now report that chemokines can serve as activating agents for immature DC. Murine bone marrow-derived DC respond to the CC chemokine RANTES (10-100 ng/ml) by production of proinflammatory mediators. RANTES induces rapid expression of transcripts for the CXC chemokines KC and macrophage inflammatory protein (MIP)-2, the CC chemokines MIP-1beta and MIP-1alpha, and the cytokines TNF-alpha and IL-6. Synthesis of KC, IL-6, and TNF-alpha proteins were also demonstrated. After 4 h, autoinduction of RANTES transcripts was observed. These responses are chemokine specific. Although DC demonstrated weak responses to eotaxin, DC failed to respond to other chemokines including KC, MIP-2, stromal-derived factor-1alpha, MIP-1beta, MIP-1alpha, monocyte chemoattractant protein-1, T cell activation gene 3, or thymus-derived chemotactic agent 4. In addition, RANTES treatment up-regulated expression of an orphan chemokine receptor termed Eo1. Chemokine induction was also observed after treatment of splenic DC and neonatal Microglia with RANTES, but not after treatment of thymocytes or splenocytes depleted of adherent cells. TNF-alpha-treated DC lose responsiveness to RANTES. DC from mice deficient for CCR1, CCR3, and CCR5 respond to RANTES, indicating that none of these receptors are exclusively used to initiate the chemokine cascade. RANTES-mediated chemokine amplification in DC may prolong inflammatory responses and shape the microenvironment, potentially enhancing acquired and innate immune responses

44. Fleige G, Nolte C, Synowitz M, Seeberger F, Kettenmann H, Zimmer C (2001) Magnetic labeling of activated Microglia in experimental gliomas. Neoplasia. 3:489-499
    Abstract: Microglia, as intrinsic immunoeffector cells of the central nervous system (CNS), play a very sensitive, crucial role in the response to almost any brain pathology where they are activated to a phagocytic state. Based on the characteristic features of activated Microglia, we investigated whether these cells can be visualized with magnetic resonance imaging (MRI) using ultrasmall superparamagnetic iron oxides (USPIOs). The hypothesis of this study was that MR Microglia visualization could not only reveal the extent of the tumor, but also allow for assessing the status of immunologic defense. Using USPIOs in cell culture experiments and in a rat glioma model, we showed that Microglia can be labeled magnetically. Labeled Microglia are detected by confocal microscopy within and around tumors in a typical border-like pattern. Quantitative in vitro studies revealed that Microglia internalize amounts of USPIOs that are significantly higher than those incorporated by tumor cells and astrocytes. Labeled Microglia can be detected and quantified with MRI in cell phantoms, and the extent of the tumor can be seen in glioma-bearing rats in vivo. We conclude that magnetic labeling of Microglia provides a potential tool for MRI of gliomas, which reflects tumor morphology precisely. Furthermore, the results suggest that MRI may yield functional data on the immunologic reaction of the CNS

45. Hentze H, Schwoebel F, Lund S, Keel M, Ertel W, Wendel A, Jaattela M, Leist M, Kehl M (2001) In vivo and in vitro evidence for extracellular caspase activity released from apoptotic cells. Biochem.Biophys.Res.Commun. 283:1111-1117
    Abstract: While caspases play an established role as intracellular executors of apoptosis, little is known about extracellular activities of this ubiquitously expressed family of proteases. We demonstrate here that recombinant caspase-3 retained enzymatic activity in various extracellular fluids. Experiments with cell lines, primary cells, and mice with fulminant CD95-triggered hepatitis showed that significant amounts of DEVD-aminofluoromethylcoumarine-cleaving activity, indicative of active effector caspases, were released into the medium/plasma during apoptosis. Furthermore, caspase activities were detected in liquor samples from human head trauma patients. These findings warrant closer investigation of DEVDase activity as a diagnostic marker, and of potential extracellular substrates for caspases

46. Hodges JL, Ireland DD, Reiss CS (2001) The role of interleukin-18 in vesicular stomatitis virus infection of the CNS. Viral Immunol. 14:181-191
    Abstract: Intranasal application of vesicular stomatitis virus (VSV) results in the initial infection of the olfactory receptor neurons and a rapid progression of the virus through the mouse central nervous system (CNS). Interleukin-18 (IL-18) is an 18.3-kd cytokine that induces interferon gamma (IFN-gamma) production in mice. IL-18 is synthesized as an inactive precursor that is cleaved and activated by caspase-1/interleukin-1beta converting enzyme (ICE). IL-18 shares several biological properties with IL-12, including the ability to induce IFN-gamma production in T lymphocytes and natural killer (NK) cells. In the CNS, Microglia and astrocytes produce IL-18 and IL-12. We have previously shown that IL-12 promotes recovery from VSV encephalitis. This led us to examine the potential role of IL-18 in the pathogenesis of VSV encephalitis. We show that both IL-18 and caspase-1 mRNA are consistently present in the CNS of mice. The addition of exogenous IL-18 to cell cultures does not affect the production of VSV, and addition of exogenous IL-18 at the time of infection does not alter the morbidity or mortality of BALB/c mice. In vitro studies with neutralizing monoclonal antibody to IL-18 had no effect. From these results we conclude that in this system and under the experimental conditions used, unlike IL-12 and IFN-gamma, IL-18 does not play a significant role in the host response to VSV infection

47. Hoozemans JJ, Rozemuller AJ, Janssen I, De Groot CJ, Veerhuis R, Eikelenboom P (2001) Cyclooxygenase expression in Microglia and neurons in Alzheimer's disease and control brain. Acta Neuropathol.(Berl) 101:2-8
    Abstract: Epidemiological studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) lower the risk of developing Alzheimer's disease (AD). Most NSAIDs act upon local inflammatory events by inhibiting the expression or activation of cylooxygenase (COX). In the present study the expression of COX-1 and COX-2 in AD and non-demented control temporal and frontal cortex was investigated using immunohistochemistry. COX-1 expression was detected in Microglial cells, while COX-2 expression was found in neuronal cells. In AD brains, COX-1-positive Microglial cells were primarily associated with amyloid beta plaques, while the number of COX-2-positive neurons was increased compared to that in control brains. No COX expression was detected in astrocytes. In vitro, primary human Microglial and astrocyte cultures, and human neuroblastoma cells (SK-N-SH) were found to secrete prostaglandin E2 (PGE2), especially when stimulated. PGE2 synthesis by astrocytes and SK-N-SH cells was stimulated by interleukin-1beta. Microglial cell PGE2 synthesis was stimulated by lipopolysaccharide only. Although astrocytes are used in studies in vitro to investigate the role of COX in AD, there are no indications that these cells express COX-1 or COX-2 in vivo. The different distribution patterns of COX-1 and COX-2 in AD could implicate that these enzymes are involved in different cellular processes in the pathogenesis of AD

48. Ito A, Saito S, Masuko T, Oh-Eda M, Matsuura T, Satoh M, Nejad FM, Enomoto T, Orikasa S, Hakomori SI (2001) Monoclonal antibody (5F3) defining renal cell carcinoma-associated antigen disialosyl globopentaosylceramide (V3NeuAcIV6NeuAcGb5), and distribution pattern of the antigen in tumor and normal tissues. Glycoconj.J. 18:475-485
    Abstract: Renal cell carcinoma (RCC) has been characterized by high expression of three types of disialogangliosides: two based on lacto-series type 1 structure (disialosyl Lc(4), GalNAc disialosyl Lc(4)), the other based on globo-series structure (disialosyl globopentaosylceramide; disialosyl Gb5). The present study established a mAb, 5F3, directed to disialosyl Gb5. 5F3 was established after immunization with RCC cell line ACHN. The major disialoganglioside antigen isolated from ACHN cells, showing specific reactivity with 5F3, was characterized unequivocally as disialosyl Gb5 (V(3)NeuAcIV(6)NeuAcGb5) by identification of the core structure as globopentaosylceramide (Gb5) after enzymatic and acid hydrolysis, and by 2-dimensional (1)H-NMR spectroscopy. 5F3 does not react with monosialosyl Gb5 (V(3)NeuAcGb5), Gb5, or any lacto-series structures. 5F3 strongly stained 19 of 41 cases of primary RCC tissue. It reacted with proximal tubules (but not distal tubules) of kidney, Microglial cells of cerebrum and cerebellum, goblet cells of stomach and intestine, smooth muscle of various organs. It did not react with parenchymatous cells of various organs, except for kidney epithelia and prostate stroma. Immunostaining of RCC tissue by mAb 5F3, in combination with staining by other antibodies directed to globo-series and lacto-series structures, has prognostic significance in defining metastatic potential of RCC

49. Keppler OT, Horstkorte R, Pawlita M, Schmidt C, Reutter W (2001) Biochemical engineering of the N-acyl side chain of sialic acid: biological implications. Glycobiology 11:11R-18R
    Abstract: N-Acetylneuraminic acid is the most prominent sialic acid in eukaryotes. The structural diversity of sialic acid is exploited by viruses, bacteria, and toxins and by the sialoglycoproteins and sialoglycolipids involved in cell-cell recognition in their highly specific recognition and binding to cellular receptors. The physiological precursor of all sialic acids is N-acetyl D-mannosamine (ManNAc). By recent findings it could be shown that synthetic N-acyl-modified D-mannosamines can be taken up by cells and efficiently metabolized to the respective N-acyl-modified neuraminic acids in vitro and in vivo. Successfully employed D-mannosamines with modified N-acyl side chains include N-propanoyl- (ManNProp), N-butanoyl- (ManNBut)-, N-pentanoyl- (ManNPent), N-hexanoyl- (ManNHex), N-crotonoyl- (ManNCrot), N-levulinoyl- (ManNLev), N-glycolyl- (ManNGc), and N-azidoacetyl D-mannosamine (ManNAc-azido). All of these compounds are metabolized by the promiscuous sialic acid biosynthetic pathway and are incorporated into cell surface sialoglycoconjugates replacing in a cell type-specific manner 10-85% of normal sialic acids. Application of these compounds to different biological systems has revealed important and unexpected functions of the N-acyl side chain of sialic acids, including its crucial role for the interaction of different viruses with their sialylated host cell receptors. Also, treatment with ManNProp, which contains only one additional methylene group compared to the physiological precursor ManNAc, induced proliferation of astrocytes, Microglia, and peripheral T-lymphocytes. Unique, chemically reactive ketone and azido groups can be introduced biosynthetically into cell surface sialoglycans using N-acyl-modified sialic acid precursors, a process offering a variety of applications including the generation of artificial cellular receptors for viral gene delivery. This group of novel sialic acid precursors enabled studies on sialic acid modifications on the surface of living cells and has improved our understanding of carbohydrate receptors in their native environment. The biochemical engineering of the side chain of sialic acid offers new tools to study its biological relevance and to exploit it as a tag for therapeutic and diagnostic applications

50. Le Y, Yazawa H, Gong W, Yu Z, Ferrans VJ, Murphy PM, Wang JM (2001) The neurotoxic prion peptide fragment PrP(106-126) is a chemotactic agonist for the G protein-coupled receptor formyl peptide receptor-like 1. J.Immunol. 166:1448-1451
    Abstract: Prion diseases are transmissible and fatal neurodegenerative disorders which involve infiltration and activation of mononuclear phagocytes at the brain lesions. A 20-aa acid fragment of the human cellular prion protein, PrP(106-126), was reported to mimic the biological activity of the pathologic isoform of prion and activates mononuclear phagocytes. The cell surface receptor(s) mediating the activity of PrP(106-126) is unknown. In this study, we show that PrP(106-126) is chemotactic for human monocytes through the use of a G protein-coupled receptor formyl peptide receptor-like 1 (FPRL1), which has been reported to interact with a diverse array of exogenous or endogenous ligands. Upon stimulation by PrP(106-126), FPRL1 underwent a rapid internalization and, furthermore, PrP(106-126) enhanced monocyte production of proinflammatory cytokines, which was inhibited by pertussis toxin. Thus, FPRL1 may act as a "pattern recognition" receptor that interacts with multiple pathologic agents and may be involved in the proinflammatory process of prion diseases

51. Platten M, Wick W, Weller M (2001) Malignant glioma biology: role for TGF-beta in growth, motility, angiogenesis, and immune escape. Microsc.Res.Tech. 52:401-410
    Abstract: Characteristics of human malignant glioma are excessive proliferation, infiltrative growth, angiogenesis and suppression of anti-tumor immune surveillance. Transforming growth factor-beta (TGF-beta), a versatile cytokine, is intimately involved in the regulation of these processes. Here, we discuss the interactions of TGF-beta with growth factors, such as basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) and platelet derived growth factor (PDGF), metalloproteinases (MMP-2, MMP-9) and their inhibitor, plasmin activator inhibitor-1 (PAI-1), and immune cells, like natural killer cells, T-cells and Microglia. The differential effects of TGF-beta in glioma biology are outlined with emphasis on the induction of a survival advantage for glioma cells by enforced cell growth, migration, invasion, angiogenesis and immune paralysis. By virtue of its growth regulatory and immunomodulatory properties, TGF-beta promises to become a novel target for the experimental therapy of human malignant glioma

52. Portis JL (2001) Genetic determinants of neurovirulence of murine oncornaviruses. Adv.Virus Res. 56:3-38

53. Proescholdt MA, Merrill MJ, Ikejiri B, Walbridge S, Akbasak A, Jacobson S, Oldfield EH (2001) Site-specific immune response to implanted gliomas. J.Neurosurg. 95:1012-1019
    Abstract: OBJECT: Immunotherapy for glioblastoma has been uniformly ineffective. The immunological environment of the brain, with its low expression of major histocompatibility complex (MHC) molecules and limited access for inflammatory cells and humoral immune effectors due to the blood-brain barrier (BBB), may contribute to the failure of immunotherapy. The authors hypothesize that brain tumors are protected from immune surveillance by an intact BBB at early stages of development. To investigate the immunological characteristics of early tumor growth, the authors compared the host response to a glioma implanted into the brain and into subcutaneous tissue. METHODS: Samples of tumors growing in the brain or subcutaneously in rats were obtained for 7 consecutive days and were examined immunohistochemically for MHC Class I & II molecules, and for CD4 and CD8 lymphocyte markers. Additionally, B7-1 costimulatory molecule expression and lymphocyte-specific apoptosis were examined. CONCLUSIONS: On Days 3 and 4 after implantation, brain tumors displayed significantly lower MHC Class II expression and lymphocytic infiltration (p < 0.05). After Day 5, however, no differences were detected. The MHC Class II expressing cells within the brain tumors appeared to be infiltrating Microglia. Minimal B7-1 expression combined with lymphocyte-specific apoptosis were detected in both brain and subcutaneous tumors. Low MHC Class II expression and low lymphocytic infiltration at early time points indicate the importance of the immunologically privileged status of the brain during early tumor growth. These characteristics disappeared at later time points, possibly because the increasing perturbation of the BBB alters the specific immunological environment of the brain. The lack of B7-1 expression combined with lymphocyte apoptosis indicates clonal anergy of glioma-infiltrating lymphocytes regardless of implantation site

54. Roth W, Isenmann S, Nakamura M, Platten M, Wick W, Kleihues P, Bahr M, Ohgaki H, Ashkenazi A, Weller M (2001) Soluble decoy receptor 3 is expressed by malignant gliomas and suppresses CD95 ligand-induced apoptosis and chemotaxis. Cancer Res. 61:2759-2765
    Abstract: Decoy receptor 3 (DcR3) is a newly identified soluble protein that binds to CD95 ligand (CD95L) and inhibits its proapoptotic activity. Here we report that DcR3 is expressed by the majority of long-term and ex vivo malignant glioma cell lines as well as in human glioblastoma in vivo. Expression of DcR3 correlates with the grade of malignancy: 15 of 18 (83%) glioblastomas (WHO grade IV) but none of 11 diffuse astrocytomas (WHO grade II) exhibited DcR3 immunoreactivity. We also demonstrate that human malignant glioma cells engineered to release high amounts of DcR3 into the cell culture supernatant are protected from CD95L-induced apoptotic cell death. In contrast, DcR3 does not confer protection from the death ligand Apo2 ligand (TRAIL). Importantly, ectopic expression of DcR3 resulted in substantial differences in immune cell infiltration in the 9L rat gliosarcoma model. Thus, the infiltration of CD4+ and CD8+ T cells as well as Microglia/macrophages into glioma was substantially decreased in DcR3-producing tumors compared with control tumors. Chemotaxis assays revealed that DcR3 counteracts the chemotactic activity of CD95L against Microglial cells in vitro. These findings suggest that DcR3 may be involved in the progression and immune evasion of malignant gliomas

55. Sugibayashi R, Shimizu T, Suzuki T, Yamamoto N, Hamada H, Takeda K (2001) Upregulation of p21(WAF1/CIP1) leads to morphologic changes and esterase activity in TPA-mediated differentiation of human prostate cancer cell line TSU-Pr1. Oncogene 20:1220-1228
    Abstract: We reported previously that human prostate cancer cell line TSU-Pr1 can differentiate into Microglia-like cells by 12-O-tetra-decanoylphorbol-13-acetate (TPA) treatment. In this study, we identified a signal transduction pathway involved in TPA-induced TSU-Pr1 cell differentiation and investigated the mechanism of growth arrest that accompanies this differentiation. TPA-induced differentiation and growth arrest of TSU-Pr1 cells were inhibited by treatment with Protein kinase C (PKC) inhibitor GF109203X and mitogen-activated protein (MAP) kinase inhibitor PD98059. Treatment of TSU-Pr1 cells with TPA for 15 min or longer resulted in translocation of PKCalpha, PKCgamma, and PKCepsilon from cytosolic to membrane fraction. Our results suggest that TPA-induced TSU-Pr1 cell differentiation is associated with activation of MAP kinase and PKCalpha, PKCgamma, and PKCepsilon. The mechanism of growth arrest in TSU-Pr1 cells that underwent TPA-induced differentiation were examined for factors in the signaling pathway downstream of MAP kinase that control the cell cycle. Upregulation of p21(WAF1/CIP1) cyclin-dependent kinase inhibitor protein was observed in a manner dependent on PKC or MAP kinase. Moreover, adenovirus-mediated overexpression of recombinant p21(WAF1/CIP1) in TSU-Pr1 cells result in growth arrest, morphological change to Microglia-like cells, and increased alpha-naphthyl acetate esterase activity, all of which are associated with cellular differentiation. Thus, our results indicate that p21(WAF1/CIP1) mediates TPA-induced growth arrest and differentiation of TSU-Pr1 cells

56. Synowitz M, Ahmann P, Matyash M, Kuhn SA, Hofmann B, Zimmer C, Kirchhoff F, Kiwit JC, Kettenmann H (2001) GABA(A)-receptor expression in glioma cells is triggered by contact with neuronal cells. Eur.J.Neurosci. 14:1294-1302
    Abstract: The expression of functional GABA(A)-receptors in glioma cells correlates with low malignancy of tumours and cell lines from glioma lack these receptors. Here we show that contact with neurons induces the expression of functional GABA(A)-receptors. C6 and F98 glioma cell lines were labelled by recombinant expression of enhanced green fluorescent protein injected into rat brain and studied in acute slices after two to three weeks of tumour growth. The cells responded to GABA or the specific agonist, muscimol with a current typical for GABA(A)-receptors, as studied with the patch-clamp technique. To get insight into the mechanism of GABA(A) receptor induction, the C6 or F98 cells were co-cultured with neurons, astrocytes, oligodendrocytes and Microglia. Glioma cells expressed functional GABA(A) receptors within 24 h only in cultures where physical contact to neurons occurred. Activation of GABA(A)-receptors in the co-cultures attenuated glioma cell metabolism while blockade of the receptors increased metabolism. We conclude that with this form of interaction, neurons can influence tumour behaviour in the brain

57. Carpentier AF, Xie J, Mokhtari K, Delattre JY (2000) Successful treatment of intracranial gliomas in rat by oligodeoxynucleotides containing CpG motifs. Clin.Cancer Res. 6:2469-2473
    Abstract: Phosphorothioate oligodeoxynucleotides with CpG motifs (CpG-ODNs) activate various immune cell subsets and induce production of numerous cytokines. To evaluate whether CpG-ODNs can induce rejection of established tumors, Lewis rats were inoculated intracerebrally with syngeneic CNS-1 glioma cells and subsequently injected with CpG-ODNs into the tumor bed. Although all of the control rats (n = 14) died within 23 days, 88% of the animals (n = 8) treated with a single CpG-ODN injection 5 days after tumor inoculation showed long-term survival (>90 days; P < 0.002). CpG-ODNs increased tumoral infiltration with macrophage/Microglial cells, CD8, and natural killer lymphocytes. CpG-ODN-cured animals were further protected against a second tumor challenge. CpG-ODNs had no effect on a s.c. CNS1 tumor in nude mice, which suggested that CpG-ODN is not directly cytotoxic and that immunostimulation is required for the antitumoral effect. These findings suggest that intratumoral injections of CpG-ODNs represent a new immunotherapeutic approach in human gliomas, which overcome the need for the selection and purification of a tumoral antigen

58. Cohen J, Sugita Y, Chader GJ, Schwartz JP (2000) Recombinant forms of the neurotrophic factor pigment epithelium-derived factor activate cellular metabolism and inhibit proliferation of the RAW macrophage cell line. Neuroimmunomodulation. 7:51-58
    Abstract: Recombinant forms of the neurotrophic factor pigment epithelium-derived factor (PEDF) activate metabolism of RAW macrophage cells while simultaneously inhibiting their proliferation. The recombinant forms (rPEDF) acted with EC(50)s of 0.1-1 nM while full-length native bovine PEDF was inactive. Urea, which is the buffer used to extract recombinant PEDF, stimulated RAW cell proliferation, the first report of an effect of urea on non-kidney cells. PEDF acted within 12 h and its effects persisted up to 72 h with continuous exposure. Although rPEDF had no direct action on glioma cell lines, it increased the amount of a soluble factor released by RAW cells which was capable of blocking glioma cell division. Thus PEDF may function as a neuroimmune modulator, affecting both neural and immune system cells

59. Dallasta LM, Wang G, Bodnar RJ, Draviam R, Wiley CA, Achim CL, Hamilton RL (2000) Differential expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in chronic murine retroviral encephalitis. Neuropathol.Appl.Neurobiol. 26:332-341
    Abstract: The cell adhesion molecules, intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1, are important mediators of immune interactions within the central nervous system (CNS). A wide variety of pro-inflammatory insults to the brain, including viral infection, result in upregulation of these molecules on brain endothelial cells, astrocytes, and Microglia. This study investigated the expression of ICAM-1 and VCAM-1 in chronic encephalitis induced by infection with a temperature sensitive (ts-1) strain of Moloney murine leukaemia virus (MoMuLV), an ecotropic murine retrovirus. During the late stages of disease, viral antigen was present in both endothelial cells and Microglia, but not astrocytes, in regions of spongiform change and gliosis. In these areas, ICAM-1 staining was detected on activated Microglia, but not on endothelial cells or astrocytes. In contrast, no cells showed increased VCAM-1 expression in the CNS. These findings demonstrate that there is cell-specific, differential expression of these adhesion molecules in ts-1 retroviral encephalitis. The lack of endothelial cell expression correlates with the characteristic lack of lymphocytic infiltrate in this chronic retroviral encephalitis and suggests that increased Microglial ICAM-1 expression may play a role in the pathogenesis of MoMuLV (ts-1)-mediated neurodegeneration

60. Deininger MH, Seid K, Engel S, Meyermann R, Schluesener HJ (2000) Allograft inflammatory factor-1 defines a distinct subset of infiltrating macrophages/Microglial cells in rat and human gliomas. Acta Neuropathol.(Berl) 100:673-680
    Abstract: Allograft inflammatory factor-1 (AIF-1) is a Ca2+-binding peptide that constitutes a potential modulator of macrophage activation and function during the immune response of the brain. Peptides termed Microglia response factor-1 or ionized calcium-binding adaptor molecule- have been reported to be identical with AIF-1. We have investigated the expression of AIF-1 in the rat C6 glioblastoma and 9L gliosarcoma tumor models and additionally assessed AIF- expression in a diverse range of human astrocytomas by immunohistochemistry. AIF-1 was expressed by activated Microglial cells and a subset of infiltrating macrophages in areas of infiltrative tumor growth and in compact tumor areas in both rat and human gliomas. Double-labeling experiments in rats and humans characterized the nature and the functional status of AIF-1+ cells. AIF-1 expression was detected in cells expressing major histocompatibility complex class II molecules and in a subset of activated macrophages/Microglial cells. All MRP-8+ cells coexpressed AIF-1. In humans, there was a strong correlation of AIF-1-expressing activated macrophages/Microglial cells with tumor malignancy (P < 0.0001). These results suggest that AIF-1 defines a distinct subset of tumor-associated activated macrophages/ Microglial cells

61. Deininger MH, Meyermann R, Trautmann K, Duffner F, Grote EH, Wickboldt J, Schluesener HJ (2000) Heme oxygenase (HO)-1 expressing macrophages/Microglial cells accumulate during oligodendroglioma progression. Brain Res. 882:1-8
    Abstract: Heme oxygenase (HO-1, HSP32) catalyzes the oxidation of heme to biliverdin and carbon monoxide, a putative neurotransmitter. In the brain, HO-1 expression has been associated with neuroprotection during oxidative stress and hypoxia. However, consecutive downstream mediation is involved in neoangiogenesis and consequent neoplastic outgrowth. We have analyzed HO-1 expression in 69 oligodendroglioma tissue samples, in rat intracranially transplanted C6 gliomas, and neuropathologically unaltered control brains by immunohistochemistry. Double labeling experiments confirmed the nature of HO-1 expressing cells. Reverse transcription-polymerase chain reaction was used to demonstrate HO-1 gene expression. HO-1 immunoreactivity was predominantly observed in macrophages/Microglial cells. The number of HO-1 expressing macrophages/Microglial cells was significantly lower in primary oligodendrogliomas than in their matched relapses (P<0.0001) and lower in primary anaplastic oligodendrogliomas than in their relapses (P=0.0006). Prominent accumulation of HO-1 expressing macrophages/Microglial cells was observed in perinecrotic areas of both experimental rat and human glioblastoma relapses. HO-1 expressing neurons, macrophages/Microglial cells and astrocytes were scattered in areas of infiltrative tumor growth. Surprisingly, HO-1 mRNA was detected in only one glioblastoma multiforme relapse. We conclude from these data that HO-1 expressing macrophages/Microglial cells accumulate during oligodendroglioma progression in areas of focal necrosis. However, overall biological function of this phenomenon remains to be determined

62. Kingham PJ, Pocock JM (2000) Microglial apoptosis induced by chromogranin A is mediated by mitochondrial depolarisation and the permeability transition but not by cytochrome c release. J.Neurochem. 74:1452-1462
    Abstract: Chromogranin A is up-regulated in the senile plaques of Alzheimer's brain and is a novel activator of Microglia, transforming them to a neurotoxic phenotype. Treatment of primary cultures of rat brain Microglia or the murine N9 Microglial cell line with chromogranin A resulted in nitric oxide production, which triggered Microglial apoptosis. Exposure of Microglia to chromogranin A resulted in a fall in mitochondrial membrane potential. Mitochondrial depolarisation and apoptosis were reduced significantly by cyclosporin A, but not by the calcineurin inhibitor FK506. Cytochrome c did not translocate from the mitochondria to the cytosol, but its expression became significantly enhanced within the mitochondria. Inhibition of caspase 1 attenuated chromogranin A-induced Microglial apoptosis, but did not prevent mitochondrial depolarisation, indicating that apoptosis occurred downstream of mitochondrial depolarisation. Conversely, staurosporine-induced Microglial apoptosis led to mitochondrial cytochrome c release, but not caspase 1 activation. Our findings provide insight into the pathways controlling activation-triggered Microglial apoptosis and may point to routes for the modulation of Microglial evoked neurotoxicity

63. Prat E, Baron P, Meda L, Scarpini E, Galimberti D, Ardolino G, Catania A, Scarlato G (2000) The human astrocytoma cell line U373MG produces monocyte chemotactic protein (MCP)-1 upon stimulation with beta-amyloid protein. Neurosci.Lett. 283:177-180
    Abstract: Astrocytes associated with beta-amyloid (Abeta) accumulate in senile plaques of Alzheimer's disease (AD). To investigate the biological effects of Abeta/astrocyte interaction, we examined chemokine production by the human astrocytoma cell line U373MG stimulated with Abeta peptides. Northern blot analysis and specific immunoassays demonstrate that Abeta [1-42] and Abeta [25-35] induce mRNA expression and release of monocyte chemotactic protein (MCP)-1 but not of gamma-interferon inducible protein (IP)-10 by U373MG cells. The observation that Abeta induces astrocyte production of the potent Microglia chemoattractant MCP-1 contributes to understanding mechanism of damage exerted by Abeta in AD senile plaques

64. Sandmair AM, Turunen M, Tyynela K, Loimas S, Vainio P, Vanninen R, Vapalahti M, Bjerkvig R, Janne J, Yla-Herttuala S (2000) Herpes simplex virus thymidine kinase gene therapy in experimental rat BT4C glioma model: effect of the percentage of thymidine kinase-positive glioma cells on treatment effect, survival time, and tissue reactions. Cancer Gene Ther. 7:413-421
    Abstract: Herpes simplex virus thymidine kinase (HSV-tk) gene transfer and ganciclovir (GCV) administration have been suggested for the treatment of malignant gliomas. To understand tissue responses and possible ways to improve the treatment effect, we studied tumor growth, tissue reactions, and survival time after HSV-tk/GCV treatment in a syngeneic BT4C rat glioma model by mixing various ratios of stably transfected HSV-tk-expressing BT4C-tk glioma cells with wild-type BT4C glioma cells (percentage of BT4C-tk cells: 0%, 1%, 10%, 30%, 50%, and 100%), followed by injection into BDIX rat brains (n = 79). With the exception of some animals with end-stage tumors, very little astroglia or Microglia reactivity was detected in the wild-type tumors as analyzed by immunocytochemistry using glial fibrillary acid protein (GFAP)-, vimentin-, human histocompatibility leukocyte antigen-DR-, OX-42-, and CD68-specific monoclonal antibodies. After 14 days of GCV treatment, tumors induced with > or = 10% BT4C-tk cells showed a significant reduction in tumor size (P < .05) and prolonged survival time (P < .01). Astrogliosis, as indicated by a strong GFAP and vimentin immunoreactivity, was seen in the tumor scar area. GFAP and vimentin reactivity was already present after the GCV treatment in tumors induced with 1% BT4C-tk cells. Much less human histocompatibility leukocyte antigen-DR-positive Microglia was seen in the treated animals, indicating low Microglia reactivity and immunoactivation against the tumor. However, GCV-treated tumors were positive for apoptosis, indicating that apoptosis is an important mechanism for cell death in the BT4C-tk glioma model. Our results suggest that > or = 10% transfection efficiency is required for a successful reduction in BT4C glioma tumor size with HSV-tk/GCV treatment in vivo. Tissue reactions after 14 days of GCV treatment are characterized by astrogliosis and apoptosis, whereas Microglia response and immunoactivation of the brain cells appear to play a minor role. Stimulation of the Microglia response by gene transfer or other means might improve the efficacy of the HSV-tk/GCV treatment in vivo

65. Satoh J, Kuroda Y (2000) Amyloid precursor protein beta-secretase (BACE) mRNA expression in human neural cell lines following induction of neuronal differentiation and exposure to cytokines and growth factors. Neuropathology. 20:289-296
    Abstract: Recently, a novel amyloid precursor protein beta-secretase (designated BACE) was identified. Because activated Microglia and astrocytes play a role in amyloidogenesis in Alzheimer's disease, the constitutive and glial cytokine/growth factor-regulated expression of BACE was studied in human neural cell lines. By reverse transcription-polymerase chain reaction (RT-PCR) analysis, BACE mRNA expression was identified in various human neural and non-neural cell lines. By northern blot analysis, the expression of BACE mRNA composed of five distinct transcripts (>8.0, 7.0, 6.0, 4.4 and 2.6 kb) was elevated markedly in NTera2 teratocarcinoma cells following retinoic acid-induced neuronal differentiation. But the levels of three major BACE mRNA species (7.0, 6.0 and 4.4 kb) were not significantly altered in NTera2-derived neurons, SK-N-SH neuroblastoma or U-373MG astrocytoma following exposure to tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, interferon-gamma, transforming growth factor-beta1, epidermal growth factor, basic fibroblast growth factor, brain-derived neurotrophic factor, dibutyryl cyclic adenosine monophosphate or phorbol 12-myristate 13-acetate. These results indicate that BACE mRNA is expressed constitutively in human neural cells and its expression is upregulated during neuronal differentiation, but it is unlikely to be regulated by activated glia-derived cytokines and growth factors

66. Satoh J, Kuroda Y (2000) Beta-catenin expression in human neural cell lines following exposure to cytokines and growth factors. Neuropathology. 20:113-123
    Abstract: Beta-catenin acts as a key mediator of the Wnt/Wingless signaling pathway involved in cell proliferation, differentiation and survival. Recent studies have shown that an unstable interaction between beta-catenin and the mutant presenilin-1 induces neuronal apoptosis, and that beta-catenin levels are decreased in the brains of patients with Alzheimer's disease (AD). Since activated Microglia and astrocytes play a role in the process of neuronal degeneration in AD, the cytokine/growth factor-regulated expression of beta-catenin in human neural cell lines, including NTera2 teratocarcinoma-derived differentiated neurons (NTera2-N), IMR-32 neuroblastoma, SKN-SH neuroblastoma and U-373MG astrocytoma, was studied quantitatively following exposure to epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, interferon (IFN)-gamma, transforming growth factor (TGF)-beta1, dibutyryl cyclic adenosine 3',5'-cyclic monophosphate (cAMP) (dbcAMP) or phorbol 12-myristate 13-acetate (PMA). Beta-catenin mRNA expressed constitutively in all of these cell lines was unaffected by treatment with any factors examined. In contrast, beta-catenin protein levels were reduced markedly in NTera2-N cells by exposure to dbcAMP, EGF or bFGF, and in U-373MG cells by treatment with dbcAMP or PMA, but were unaffected in any cell lines by BDNF, TNF-alpha, IL-1beta, IL-6, IFN-gamma or TGF-beta1. These results indicate that beta-catenin is expressed constitutively in human neural cells and downregulated at a protein level by a set of growth factors in a cell type-specific manner

67. Shieh JT, Martin J, Baltuch G, Malim MH, Gonzalez-Scarano F (2000) Determinants of syncytium formation in Microglia by human immunodeficiency virus type 1: role of the V1/V2 domains. J.Virol. 74:693-701
    Abstract: Microglia are the main reservoir for human immunodeficiency virus type 1 (HIV-1) in the central nervous system (CNS), and multinucleated giant cells, the result of fusion of HIV-1-infected Microglia and brain macrophages, are the neuropathologic hallmark of HIV dementia. One potential explanation for the formation of syncytia is viral adaptation for these CD4(+) CNS cells. HIV-1(BORI-15), a virus adapted to growth in Microglia by sequential passage in vitro, mediates high levels of fusion and replicates more efficiently in Microglia and monocyte-derived-macrophages than its unpassaged parent (J. M. Strizki, A. V. Albright, H. Sheng, M. O'Connor, L. Perrin, and F. Gonzalez-Scarano, J. Virol. 70:7654-7662, 1996). Since the interaction between the viral envelope glycoprotein and CD4 and the chemokine receptor mediates fusion and plays a key role in tropism, we have analyzed the HIV-1(BORI-15) env as a fusogen and in recombinant and pseudotyped viruses. Its syncytium-forming phenotype is not the result of a switch in coreceptor use but rather of the HIV-1(BORI-15) envelope-mediated fusion of CD4(+)CCR5(+) cells with greater efficiency than that of its parental strain, either by itself or in the context of a recombinant virus. Genetic analysis indicated that the syncytium-forming phenotype was due to four discrete amino acid differences in V1/V2, with a single-amino-acid change between the parent and the adapted virus (E153G) responsible for the majority of the effect. Additionally, HIV-1(BORI-15) env-pseudotyped viruses were less sensitive to decreases in the levels of CD4 on transfected 293T cells, leading to the hypothesis that the differences in V1/V2 alter the interaction between this envelope and CD4 or CCR5, or both. In sum, the characterization of the envelope of HIV-1(BORI-15), a highly fusogenic glycoprotein with genetic determinants in V1/V2, may lead to a better understanding of the relationship between HIV replication and syncytium formation in the CNS and of the importance of this region of gp120 in the interaction with CD4 and CCR5

68. Taniguchi Y, Ono K, Yoshida S, Tanaka R (2000) Antigen-presenting capability of glial cells under glioma-harboring conditions and the effect of glioma-derived factors on antigen presentation. J.Neuroimmunol. 111:177-185
    Abstract: The antigen-presenting capability of syngeneic rat glial cells was investigated under glioma-harboring conditions. Microglia induced a significant proliferation of glioma-primed splenocytes, but astrocytes did not. Furthermore, astrocytes suppressed the accessory cell function of Microglia. The presence of both indomethacin and anti-interleukin (IL)-10 neutralizing antibody during priming of Microglia enhanced splenocyte proliferation. The glioma culture supernatants down-regulated the interferon-gamma-induced expression of major histocompatibility complex class II molecules on Microglia. The down-regulation was blocked by indomethacin and anti-IL-10 antibody. The results suggest that Microglia but not astrocytes may function as antigen-presenting cells in glioma, and that glioma may suppress the antigen-presenting abilities of Microglia

69. Thomas A, Gasque P, Vaudry D, Gonzalez B, Fontaine M (2000) Expression of a complete and functional complement system by human neuronal cells in vitro. Int.Immunol. 12:1015-1023
    Abstract: We demonstrate in vitro expression of complement components, i.e. C3, factor H (FH), factor B (FB), C4, C1-inhibitor (C1-inh), C1q, C5, C6, C7 and C9, by four human neuroblastoma cell lines IMR32, SKNSH, SH-SY5Y and KELLY. Activating proteins C4, C9 and C1q, and regulatory proteins FH and C1-inh were produced constitutively by the four cell lines. C3, C6 and FB were mainly produced by SKNSH and SH-SY5Y. Western blot experiments showed that secreted proteins were structurally similar to their serum counterparts. An additional polypeptide of 43 kDa with FH immunoreactivity was detected, which could correspond to the N-terminal truncated form found in plasma. Regulatio