The objectives of this research are to utilize model systems in cell culture to provide insight into the following phenomena in differentiating astrocytes, oligodendroglia, and neurons: (1) the interrelations of cholestrerol and dolichol-dolichylphosphate (do1/do1-P) biosyntheses and the role of HMG-CoA reductase in modulating these interrelations, (2) the regulation of do1/do1-P metabolism and dolichol-linked oligosaccharide and glycoprotein (DLOG) biosyntheses, (3) the relation of do1/do1-P metabolism and DLOG biosyntheses to astrocytic, oligodendroglial, and neuronal differentiation , and (4) the role of thyroid hormone in the regulation of do1/do1-P metabolism and DLOG biosyntheses. In all of the experiments proposed, primary cultures of astrocytes, oligodendroglia or neurons, isolated as essentially homogenous preparations, will be utilized. Concerning the interrelations of cholesterol and do1/do-P biosyntheses, we will determine the extent to which these biosyntheses are regulated coordinately at a critical enzymatic step common to both pathways, i.e., HMG-CoA reductase. Concerning the regulation of do1/do-P metabolism and DLOG biosyntheses, we will define the enzymatic steps controlling the regulation of dolichyl phosphate levels and the utilization of dolicyl phosphate for oligosaccharide biosynthesis. Concerning the relation of do1/do1-P metabolism and DLOG biosyntheses to astroglial, oligodendroglial and nueuronal differentiation, two major series of experiments will be important. First, correlation of specific biochemical indicators of differentiation of the three cell types with specific aspects of dol/dol-P metaboslism and DLOG biosyntheses, described immediatlely above, will be accomplished. Second, we will determine whether these biochemical events in the dolichol-linked pathway are obligatory for the specific expressions of cellular differentiation. Thus, we will determine the effect on these expressions of differentiation of inhibition of either (a) dolichyl phophaste biosynthesis, i.e., by mevinolin, or (b) dolichol-linked oligosaccharide biosynthesis, i.e., by tunicamycin. Concerning the role of thyroid hormone importance of this work relates to previous studies which demonstrate the important role of thyroid hormone in brain development, particularly cellular differentiations, and to our preliminary data which indicate a regulatory role for thyroid hormone in the dolichol-linked pathway in at least the astrocytes and oligodendrogia.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD007464-14A1
Application #
3310681
Study Section
Metabolism Study Section (MET)
Project Start
1976-12-01
Project End
1992-06-30
Budget Start
1987-07-01
Budget End
1988-06-30
Support Year
14
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Washington University
Department
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
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Ishii, S; Volpe, J J (1988) Dolichol-linked oligosaccharide and glycoprotein biosyntheses in glial cells in primary culture: development and enzymatic correlates. J Neurosci Res 20:463-72
Volpe, J J; Sakakihara, Y; Ishii, S (1987) Dolichol-linked glycoprotein synthesis in developing mammalian brain: maturational changes of the N-acetylglucosaminylphosphotransferase. Brain Res 430:277-84
Langan, T J; Volpe, J J (1987) Cell cycle-specific requirement for mevalonate, but not for cholesterol, for DNA synthesis in glial primary cultures. J Neurochem 49:513-21

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