Morphological and molecular response of the MOCH‐1 oligodendrocyte cell line to serum and interferon‐γ: Possible implications for demyelinating disorders

The regional loss of oligodendrocytes is thought to be an important pathological event in a variety of demyelinating diseases of the central nervous system (CNS). Various components of serum, which are normally excluded from the CNS by the blood‐brain barrier, have been implicated as mediators of demyelinating disorders. We have examined the effects of high concentrations of serum (10% fetal bovine serum, FBS), as well as the cytokine interferon‐γ (IFN‐γ), on an oligodendrocyte cell line, MOCH‐1 cells. These cells changed from phase‐bright, small round cells with multiple thin, branched processes in 1% FBS medium to flat, fibroblast‐like cells with large cell bodies when cultured in 10% FBS medium or 1% FBS medium containing IFN‐γ. These morphological changes were accompanied by a large increase in expression of the astrocyte marker, glial fibrillary acidic protein (GFAP), as detected by Northern and Western blot analyses. In addition, Northern blot and fluorescence‐activated cell sorting analyses revealed that IFN‐γ induced a very large increase in major histocompatibility complex (MHC) class I expression in MOCH‐1 cells. MHC class II mRNA induction by IFN‐γ was also seen. In contrast, 10% FBS did not elevate either MHC class I or class II mRNA levels in MOCH‐1 cells. The morphological and molecular effects of 10% FBS and IFN‐γ were reversible. We suggest that the response of MOCH‐1 cells to high concentrations of serum and IFN‐γ may reflect an important in vivo response to oligodendrocytes to perturbations that occur in demyelinating disorders. © 1995 Wiley‐Liss, Inc.