Redox regulation of cytokine-mediated inhibition of myelin gene expression in human primary oligodendrocytes

Abstract

Multiple sclerosis (MS) is a chronic autoimmune demyelinating disorder of the central nervous system (CNS) of unknown etiology. Several studies have shown that demyelination in MS is caused by proinflammatory mediators which are released by perivascular infiltrates and/or activated glial cells. To understand if proinflammatory mediators such as IL (interleukin)-1β and TNF (tumor necrosis factor)-α are capable of modulating the expression of myelin-specific genes, we investigated the effect of these cytokines on the expression of myelin basic protein (MBP), 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase), myelin oligodendrocyte glycoprotein (MOG), and proteolipid protein (PLP) in human primary oligodendrocytes. Interestingly, both IL-1β and TNF-α markedly inhibited the expression of MOG, CNPase, and PLP but not MBP, the effect that was blocked by antioxidants such as N-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC). Consistently, oxidants and prooxidants like H 2 O 2 and diamide also markedly inhibited the expression of MOG, CNPase, and PLP. Furthermore, both IL-1β and TNF-α induced the production of H 2 O 2 . Taken together, these studies suggest that proinflammatory cytokines inhibit the expression of myelin genes in human primary oligodendrocytes through the alteration of cellular redox.

Gemfibrozil, a Lipid-lowering Drug, Increases Myelin Genes in Human Oligodendrocytes via Peroxisome Proliferator-activated Receptor-β

“…These cells were positive for GalC, MBP, MOG, PLP, and CNPase (1, 2). However, we were unable to detect any GFAP-positive astroglia and CD11b-positive microglia in this oligodendroglial preparation (1,2). Rarely did we observe one GFAP-positive astrocyte of 50 or more GalC-positive oligodendrocytes (1, 2).…”

“…The non-adhering cells (mostly oligodendrocytes) were seeded onto poly-D-lysine-coated culture plates in complete medium (DMEM/F-12 supplemented with 10% heat inactivated FBS) at 37°C with 5% CO 2 in air. Earlier we (1,2) have shown that oligodendrocytes isolated through this procedure are more than 98% pure.…”

“…Immunostaining of GalC, CNPase, MOG, PLP, and PPAR-␤-Immunostaining was performed as described earlier (1,2). Briefly, coverslips containing 200 -300 cells/mm 2 were fixed with 4% paraformaldehyde for 15 min followed by treatment with cold ethanol (Ϫ20°C) for 5 min and two rinses in PBS.…”

“…Real Time PCR Analysis-Real time PCR analysis was performed using the ABI PRISM 7700 sequence detection system (Applied Biosystems, Foster City, CA) as described earlier (1,25). All primers and fluorescein amidite-labeled probes were obtained from Applied Biosystems.…”

Activation of Peroxisome Proliferator-activated Receptor α Induces Lysosomal Biogenesis in Brain Cells

“…Isolation of Primary Mouse Neurons-Fetal (E18 to E16) mouse neurons were prepared as described previously (27) with modifications. Whole brains were removed, and the cells were washed by centrifugation three times at 1000 rpm for 10 min, the pellet dissociated, and the cells plated at 10% confluence in 8-well chamber slides pretreated for Ͼ2 h with poly-D-lysine (Sigma).…”