Ethanol (EtOH) is a potent teratogen for the developing nervous system and causes a variety of abnormal neurological effects in children born of alcoholic mothers, referred to as the fetal alcohol syndrome (FAS). One factor involved in the EtOH-caused neurological defects appears to be abnormal formation of myelin. We are identifying the regulatory processes affected by EtOH which result in dysmyelination by using the non-neoplastic continuous CG-4 line of oligodendrocytes (OLGs). CG-4 progenitors differentiate into OLGs in the virtual absence of supporting cells and are a good model to identify the effects of EtOH that directly affect signaling in OLGs. Exposure of differentiating CG-4 cells to relatively clinical levels of EtOH alters the temporal and quantitative expression of ethanolamine plasmalogen (EP1), a major lipid in myelin. EtOH inhibits the expression of myelin basic protein (MBP), but not that of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP). By using modulators of PKC, we showed that EtOH inhibited MBP expression by activating PKC without increasing the expression of any of the 9 PKC isozymes detected in CG4 0LGs. We are planning to use the same approach to identify which PKC isozyme is activated by EtOH to cause inhibited MBP expression by using isozyme-specific peptide inhibitors. We also plan to determine the isozyme involved by expanding our studies of treating OLGs with isozyme-specific antisense oligodeoxyribonucleotides to selectively inhibit the expression of specific PKC isozymes. We will use cell fractionation to determine which PKC isozyme(s)EtOH activates by increasing its distribution in the membrane fraction and which PKC classes display increased enzyme activity. By using immunocytochemical confocal microscopy we have found that the classical PKCs have unique subcellular localizations. We now will expand those preliminary studies to determine if EtOH affects PKC functions in OLGs by altering the subcellular localization of specific PKC isozymes, as it does in other cell types. We will study the effects of EtOH on MBP expression in primary cultures of OLGs. The proposed studies of identifying the role of specific PKC isozymes in cellular processes are of major interest to develop clinical isozyme-specific modulators to alleviate disease processes or correct pathology, such as demyelination or dysmyelination resulting from FAS, other pathological conditions, or trauma ? ?
| Bichenkov, Eugeney; Ellingson, John S (2009) Ethanol alters the expressions of c-Fos and myelin basic protein in differentiating oligodendrocytes. Alcohol 43:627-34 |
