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Impaired differentiation of HPRT‐deficient dopaminergic neurons: A possible mechanism underlying neuronal dysfunction in Lesch‐Nyhan syndrome
Author(s) -
Yeh Jason,
Zheng Shuang,
Howard Bruce D.
Publication year - 1998
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19980701)53:1<78::aid-jnr8>3.0.co;2-g
Subject(s) - hypoxanthine guanine phosphoribosyltransferase , lesch–nyhan syndrome , dopaminergic , dopamine , hypoxanthine , biology , choreoathetosis , phosphoribosyltransferase , purine , mutant , endocrinology , medicine , microbiology and biotechnology , biochemistry , neuroscience , enzyme , dystonia , gene
Lesch‐Nyhan syndrome is a hereditary disorder of purine metabolism causing overproduction of uric acid and neurological problems including spasticity, choreoathetosis, mental retardation, and compulsive self‐mutilation. The syndrome is caused by a defect in the enzyme hypoxanthine‐guanine phosphoribosyltransferase (HPRT), which converts guanine and hypoxanthine to the nucleotides GMP and IMP. There is evidence that the neurological problems are due to an adverse effect of the HPRT deficiency on the survival and/or development of dopaminergic neurons, specifically. Here we report that HPRT‐deficient PC12 mutants that have a normal or near normal dopamine content (55–97% of that of wild‐type cells) fail to undergo neuronal differentiation induced by nerve growth factor (NGF) when the de novo pathway of purine synthesis is partially inhibited. However, nerve growth factor‐induced differentiation is near normal under these conditions in PC12 HPRT‐deficient mutants containing much lower dopamine levels (<8% of that of wild type cells), indicating a neurotoxic effect of the endogenous dopamine in the mutants. The degree of inhibition of the de novo pathway of purine synthesis was the same in both classes of HPRT‐deficient mutants. Expression of BCl‐2 in a PC12 mutant that has a normal dopamine content allowed partial NGF‐induced differentiation suggesting that the apoptotic pathway might be involved in the failure of differentiation when the de novo pathway of purine synthesis is partially inhibited. J. Neurosci. Res. 53:78–85, 1998. Published 1998 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.