Diminished cytokine and chemokine expression in the central nervous system of GMF-deficient mice with experimental autoimmune encephalomyelitis

Abstract

Pro-inflammatory cytokines/chemokines are implemented in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model with clinical and pathological similarities to multiple sclerosis. We have previously shown that over-expression of glia maturation factor (GMF) in glial cells cause excessive production and secretion of pro-inflammatory cytokines/chemokines sufficient to destroy the myelin-forming oligodendroglial cell in vitro. In this present investigation, we evaluate the expression of pro-inflammatory mediators in the central nervous system (CNS) of GMF+/+ (wild type) mice and GMF−/− (GMF-knockout) mice at the peak of EAE induced by immunization with MOG 35–55 peptide. GMF+/+ (Wt) mice developed severe EAE with a maximal mean clinical score of 3.6 ± 0.5 by day 16 post-immunization, whereas GMF-KO mice showed significantly delayed EAE with an average onset on day 26 pi with reduced mean clinical score of 1.3 ± 0.3. Three of fifteen Wt mice as compared to none of GMF-KO mice died of EAE. Encephalitogenic cells from Wt mice transferred to recipient GMF-KO mice caused very mild and with low incidence of EAE. We determined the differences in the expression of cytokines, IFN-γ, TNF-α, IL-1 β, IL-6, IL-4, IL-10, and chemokines, MIP-1, MIP-2, IP-10, MCP-1, GM-CSF mRNA by quantitative real-time RT–PCR in brain and spinal cord. Our results demonstrate significantly low levels of pro-inflammatory cytokines/chemokines in the CNS of GMF-KO mice and increased expression in Wt mice with EAE. Our data suggest that GMF play a critical role in CNS inflammation.