LPS/IFN-gamma cytotoxicity in oligodendroglial cells: role of nitric oxide and protection by the anti-inflammatory cytokine IL-10.
Proinflammatory mediators have been implicated in demyelinating disorders, including multiple sclerosis, whereas it has been proposed that the anti-inflammatory cytokines interleukin- (IL-) 4 and IL-10 participate in disease recovery. The present study analysed the effect of interferon-gamma (IFN-gamma) and bacterial endotoxin (lipopolysaccharide, LPS) on proliferation and survival of progenitors and differentiated oligodendrocytes. We also investigated the presence of receptors for IL-4 and IL-10 in oligodendroglial cells and explored a possible protective action of IL-4 and IL-10 in cultures following LPS/IFN-gamma. Finally, the role of endogenous nitric oxide (NO) on cell viability and the modulatory action of IL-4 and IL-10 on inducible nitric oxide synthase (iNOS) expression were also analysed. We report that LPS and/or IFN-gamma reduced proliferation and viability of oligodendroglial cells. Cell death, presumably by apoptosis as evidence by TUNEL and Annexin V binding, was observed following LPS/IFN-gamma, progenitors being more sensitive than differentiated cells. At both developmental stages, LPS/IFN-gamma-treated cultures expressed iNOS protein and released micromolar concentrations of NO. In progenitors, LPS/IFN-gamma-mediated cell damage was partially dependent on endogenous NO production, whereas NO was fundamental for cytotoxicity of differentiated oligodendrocytes. Both cell types expressed mRNA for IL-4 and IL-10 receptors and expression of IL-10 receptors at the protein level was also demonstrated. Treatment with either cytokine inhibited the expression of iNOS resulting from the proinflammatory stimulation. IL-10 was more effective than IL-4 in suppressing iNOS expression and, interestingly, IL-10 conferred protection against oligodendroglial death evoked by LPS/IFN-gamma. Our data raise the question of whether IL-10 may play a protective role in demyelinating diseases, not only downregulating the function of inflammatory cells but also promoting survival of progenitors and differentiated oligodendrocytes.
Molina-Holgado
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E
Neural Plasticity Unit, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, 28002 Madrid, Spain.
Vela
J M
JM
Arévalo-Martín
A
A
Guaza
C
C
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D001921:Brain / Q000166:cytology; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D007371:Interferon-gamma / Q000633:toxicity*; D016753:Interleukin-10 / Q000276:immunology*; D015847:Interleukin-4 / Q000276:immunology; D008070:Lipopolysaccharides / Q000633:toxicity*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009836:Oligodendroglia / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D051381:Rats; D018123:Receptors, Interleukin / Q000032:analysis; D053701:Receptors, Interleukin-10; D019948:Receptors, Interleukin-4 / Q000032:analysis; D013234:Stem Cells / Q000737:chemistry / Q000166:cytology / Q000201:enzymology
D008070:Lipopolysaccharides; D018123:Receptors, Interleukin; D053701:Receptors, Interleukin-10; D019948:Receptors, Interleukin-4; D016753:Interleukin-10; D015847:Interleukin-4; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat