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Glial cell pathobiology in multiple sclerosis detected by CSF markers
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43 ANTI-M5P PROTEOLYTIC ACTIVITY PROM MICROGLIA AND MACROPHAGES INPECTED WITH THEILER’S MURINE ENCEPHALOMYRLITISVIRUS G.M. Liuzzi, OP.Riccio and ‘M.C. Dal Canto University of Bari,,Bari, “University of Basilic&a, Potenza, Italy and *Northwestern Untverstty, Chicago, IL, USA.
GLIAL CELL PATHOliiOLOGY IN MULTIPLE SCLEROSIS DETECTED BY CSF MARKERS A.R.Massaro, “Sacro Cuore” University, Roma, Italy. The unforeseable evolution of MS, and the still enigmatic concatenation of pathobiological events, make it a primary goal for researchers to have sensitive and specific markers for follow-up studies. MRI was demonstrated to be an excellent means, but it is not able to discriminate the role of the various cell types involved. We performed a followup study on CSF samples from relapsing-remitting MS patients, testing several markers of different cell types: MBP for myelin sheath, GFAP and S-100 for astrocytes, NCAM for monitoring adhesion phenomena. Interesting results were obtained with S-100 and N-CAM, which are increased during the period following an exacerbation. S-100 showed early increase after the attack, as a sign of a precocious involvement of these cells in the acute plaque formation. On the contrary, CSF N-CAM increased later on, possibly as a marker of remyelination related events. 46
45
REJECTION OF XENOCENEIC GLIAL CELLS GRAFTED INTO SPINAL CORD WHITE MATTER RESULTS IN BYSTANDER DEMYELINATION University of Cambridge. U.K. The susceptibility of oligodendrocytes and myelin to bystander inflammation in the CNS is a controversialissue. yet is of Importance in understandingthe pathogenesisof demyelinatingdiseasessuch as MS and EAE. In order to induce a localised area of inflammation in CNS white matter, a suspensionof male mouse mixed glial cells was grafted into normal rat spinal cord white matter. Survival of male mouse cells was monitored using a probe which hybridises specifically to the mouse Y chromosome. By 2 weeks following transplantation, xenogeneic cells could not be detected and a dense infIammatory infiltrate extended well beyond the area occupied by the graft. Demyelinated axons were seen at the centre of the inflammatory infiltrate. By 4 weeks, inflammation had subsided, and remyelinated axons were present in the localised area corresponding to the site previously occupied by the graft. Thus; although bystander demyelination occurred as a result of inflammation, the demyelinatedarea was small comparedto the size of the inflammatory inliltrate. This suggests that bystander demyelination occurs only at the
site immediately adjacent to the target of the immune response.
47 ASTBGCYTBS AS TARGETS OF THB HIV-l gp 120 GLYCO PROTEIN ACTION. F.f&&&, G.&K&E~, F.&&yaz and J.&l&&&i, DIBIT, Scientific Institute San Raffaele, CNR Cytopharmacology Center atxl University of Milano. Nemotoxicity reported in numerous AIDS patients is still poorly explained. Previous studies suggested netmmal damage to be indirect, mediated via the release of the envelope glycqxotein, gp120, and the activation of glutamatergic receptors and Ca*+ channels. Extensive atuclles of cell cu1tute.s from various brain areas, investigated by single cell [Caz+liimaging, failed however to reveal responses in neurons, even when located in close opposition with other types of cells. In contrast, responses to low concentrations of
gp120 were constantly recorded in gllal cells identified by immunocyto&m&y as astrocytes and ollgodendroeytes. ‘Ihe proportion of responding cells increased markedly when cultures were bathed in Na+-free medium. suggesting the involvement of the Na+/Ca+exchanger. In contrast, blocker experiments excluded any involvement of glutamate@c receptom and voltagegated Ca*+ chamkzls. Ihe apparently direct action of gp120 might modify significantly astrocyte function, leading to conditions ultimately toxic for netuons as well.
INFLUENCE OF HIV VIRAL PROTEINS AND CYTOKINESON OLECFE EXPRESSION BY GLIAL CELLS. E&, P. &&I&. University of Alabama at Birmingham, Birmingham, AL 35294. It is well established that the two major gliai cells in the central nervous system (CNS), asuocytes and microglia, ate key participants in mediating nenmlogic dysfunction associated with HIV infection of the CNS. In this study, we investigated the ability of the major envelope I co tein of HIV, gp120, to regulate intercelIuIat adhesion molecule-l 1) expression in glII cells, because ICAM- is important in mediating immtme respnusiveness in the CNS, facilitating entry of HIVinfected cells into me CNS, and promoting syncytia formation. Our results indicate that gp120 is a potent enhancer of ICAM- gene expression in piimaty rat astmcytes, primaty human astmoytes, a haman astroglloma cell line CRT, and rlmary rat tnicroglla. The signal transduction events involved in gpl gO-mediated enltancemettt of ICAMappear to involve activation of both protein kinase C @‘KC) and tyrosine kinase (TK), because inhibitors of PKC and TK abrogate gpl20-mediated ICAM- expression in both astrocytes and microgii Moreoves, gp120 induces tyrosine phosphorybttion of Signal kfansducer and activator of uansctiption (STAT-la) as well as the Janus Khtase (JAK2) in glial cells. We also demonstrate that gplPO-mediated ICAM- expression has functional significance, as it enhances the ability of monoc tic cells to bind to gpl20-sthmtiated human astrocytes in an ICAM-l/ 2 integtindependent fashion. Cytokines such as TNF-a, IL-@, an i IFN-T also influence ICAM- exuression in allal cells, and the htteractions between gp120 and these cyt&nes will 6e discussed. Supported by NIH grant MH50421 and AmFAR grant 0240%19-RG (B.N.B.).
$I& ARfp
46 THE ROLE OF TNFa ON INFECTION IN GLIAL CELLS
MUIUNE
AlDS
VIRUS
A. SUZUMURA, M. SAWADA, *M. MAKINO Fuji@ Health Univ., l Kagosbima Univ. To examine the roles of TNFa on it&ction of glial cells with mmine AIDS virus, LP-BMS, we examined the effects of pemoxiij4liue, pmpesuoij4liue aud veauarinone ott TNFa production and LP-BMS htfection in glial cells. Effects of T’NFa and anti-TNFa on LP-BM5 i&ction in glial cells were also examiued. Pet1toxiIj4lme+ pmpaitofylline attd veanariuone effectively qpremed LPS-induced TNFa prod&on by miuoglia and as&cqma, and alao aignificatttly inhibited productive infeotion of LP-BMS in @ial cells. Additiou of TNFa ahotiahed the suppressive effecta of these drugs, and anti-TNFa alone had similar suppressive effeota againat LPBM5 ittfectiou in Elial cells. Titus, TNFa may play 8 critical role in the developmestt of LPBh45 infecrion in glial cells and the #on of TNFa with ahove agenta may he of use for the treatment of muritm, and possibly humin& AlDs vhua i&ctiott.
43 ANTI-M5P PROTEOLYTIC ACTIVITY PROM MICROGLIA AND MACROPHAGES INPECTED WITH THEILER’S MURINE ENCEPHALOMYRLITISVIRUS G.M. Liuzzi, OP.Riccio and ‘M.C. Dal Canto University of Bari,,Bari, “University of Basilic&a, Potenza, Italy and *Northwestern Untverstty, Chicago, IL, USA.
GLIAL CELL PATHOliiOLOGY IN MULTIPLE SCLEROSIS DETECTED BY CSF MARKERS A.R.Massaro, “Sacro Cuore” University, Roma, Italy. The unforeseable evolution of MS, and the still enigmatic concatenation of pathobiological events, make it a primary goal for researchers to have sensitive and specific markers for follow-up studies. MRI was demonstrated to be an excellent means, but it is not able to discriminate the role of the various cell types involved. We performed a followup study on CSF samples from relapsing-remitting MS patients, testing several markers of different cell types: MBP for myelin sheath, GFAP and S-100 for astrocytes, NCAM for monitoring adhesion phenomena. Interesting results were obtained with S-100 and N-CAM, which are increased during the period following an exacerbation. S-100 showed early increase after the attack, as a sign of a precocious involvement of these cells in the acute plaque formation. On the contrary, CSF N-CAM increased later on, possibly as a marker of remyelination related events. 46
45
REJECTION OF XENOCENEIC GLIAL CELLS GRAFTED INTO SPINAL CORD WHITE MATTER RESULTS IN BYSTANDER DEMYELINATION University of Cambridge. U.K. The susceptibility of oligodendrocytes and myelin to bystander inflammation in the CNS is a controversialissue. yet is of Importance in understandingthe pathogenesisof demyelinatingdiseasessuch as MS and EAE. In order to induce a localised area of inflammation in CNS white matter, a suspensionof male mouse mixed glial cells was grafted into normal rat spinal cord white matter. Survival of male mouse cells was monitored using a probe which hybridises specifically to the mouse Y chromosome. By 2 weeks following transplantation, xenogeneic cells could not be detected and a dense infIammatory infiltrate extended well beyond the area occupied by the graft. Demyelinated axons were seen at the centre of the inflammatory infiltrate. By 4 weeks, inflammation had subsided, and remyelinated axons were present in the localised area corresponding to the site previously occupied by the graft. Thus; although bystander demyelination occurred as a result of inflammation, the demyelinatedarea was small comparedto the size of the inflammatory inliltrate. This suggests that bystander demyelination occurs only at the
site immediately adjacent to the target of the immune response.
47 ASTBGCYTBS AS TARGETS OF THB HIV-l gp 120 GLYCO PROTEIN ACTION. F.f&&&, G.&K&E~, F.&&yaz and J.&l&&&i, DIBIT, Scientific Institute San Raffaele, CNR Cytopharmacology Center atxl University of Milano. Nemotoxicity reported in numerous AIDS patients is still poorly explained. Previous studies suggested netmmal damage to be indirect, mediated via the release of the envelope glycqxotein, gp120, and the activation of glutamatergic receptors and Ca*+ channels. Extensive atuclles of cell cu1tute.s from various brain areas, investigated by single cell [Caz+liimaging, failed however to reveal responses in neurons, even when located in close opposition with other types of cells. In contrast, responses to low concentrations of
gp120 were constantly recorded in gllal cells identified by immunocyto&m&y as astrocytes and ollgodendroeytes. ‘Ihe proportion of responding cells increased markedly when cultures were bathed in Na+-free medium. suggesting the involvement of the Na+/Ca+exchanger. In contrast, blocker experiments excluded any involvement of glutamate@c receptom and voltagegated Ca*+ chamkzls. Ihe apparently direct action of gp120 might modify significantly astrocyte function, leading to conditions ultimately toxic for netuons as well.
INFLUENCE OF HIV VIRAL PROTEINS AND CYTOKINESON OLECFE EXPRESSION BY GLIAL CELLS. E&, P. &&I&. University of Alabama at Birmingham, Birmingham, AL 35294. It is well established that the two major gliai cells in the central nervous system (CNS), asuocytes and microglia, ate key participants in mediating nenmlogic dysfunction associated with HIV infection of the CNS. In this study, we investigated the ability of the major envelope I co tein of HIV, gp120, to regulate intercelIuIat adhesion molecule-l 1) expression in glII cells, because ICAM- is important in mediating immtme respnusiveness in the CNS, facilitating entry of HIVinfected cells into me CNS, and promoting syncytia formation. Our results indicate that gp120 is a potent enhancer of ICAM- gene expression in piimaty rat astmcytes, primaty human astmoytes, a haman astroglloma cell line CRT, and rlmary rat tnicroglla. The signal transduction events involved in gpl gO-mediated enltancemettt of ICAMappear to involve activation of both protein kinase C @‘KC) and tyrosine kinase (TK), because inhibitors of PKC and TK abrogate gpl20-mediated ICAM- expression in both astrocytes and microgii Moreoves, gp120 induces tyrosine phosphorybttion of Signal kfansducer and activator of uansctiption (STAT-la) as well as the Janus Khtase (JAK2) in glial cells. We also demonstrate that gplPO-mediated ICAM- expression has functional significance, as it enhances the ability of monoc tic cells to bind to gpl20-sthmtiated human astrocytes in an ICAM-l/ 2 integtindependent fashion. Cytokines such as TNF-a, IL-@, an i IFN-T also influence ICAM- exuression in allal cells, and the htteractions between gp120 and these cyt&nes will 6e discussed. Supported by NIH grant MH50421 and AmFAR grant 0240%19-RG (B.N.B.).
$I& ARfp
46 THE ROLE OF TNFa ON INFECTION IN GLIAL CELLS
MUIUNE
AlDS
VIRUS
A. SUZUMURA, M. SAWADA, *M. MAKINO Fuji@ Health Univ., l Kagosbima Univ. To examine the roles of TNFa on it&ction of glial cells with mmine AIDS virus, LP-BMS, we examined the effects of pemoxiij4liue, pmpesuoij4liue aud veauarinone ott TNFa production and LP-BMS htfection in glial cells. Effects of T’NFa and anti-TNFa on LP-BM5 i&ction in glial cells were also examiued. Pet1toxiIj4lme+ pmpaitofylline attd veanariuone effectively qpremed LPS-induced TNFa prod&on by miuoglia and as&cqma, and alao aignificatttly inhibited productive infeotion of LP-BMS in @ial cells. Additiou of TNFa ahotiahed the suppressive effecta of these drugs, and anti-TNFa alone had similar suppressive effeota againat LPBM5 ittfectiou in Elial cells. Titus, TNFa may play 8 critical role in the developmestt of LPBh45 infecrion in glial cells and the #on of TNFa with ahove agenta may he of use for the treatment of muritm, and possibly humin& AlDs vhua i&ctiott.