Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases but its etiology is unclear. alpha-Synuclein (alpha-SN) is a major component of Lewy bodies and Lewy neurites, and its missense mutations, A30P and A53T, cause familial PD. In PD, alpha-SN-positive glial inclusions are distributed mainly in the dorso-medial region of the substantia nigra, which contains most of the surviving dopaminergic neurons, suggesting that alpha-SN expression might have a neuroprotective function in glial cells. To investigate this hypothesis, we established alpha-SN transfected C6 glioma cell line clones and evaluated the expression of neurotrophins using semi-quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Brain-derived neurotrophic factor (BDNF) was induced by overexpression of wild-type alpha-SN but not by that of A30P and A53T. These data suggest that the pathogenic alpha-SN mutations, A30P or A53T, are linked to the loss of BDNF production in glial cells. (C) 2004 Elsevier Inc. All rights reserved.