Cultured fibroblasts in Huntington's disease. I. Effects of L-glutamic acid

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Huntington's disease (HD) is linked to central nervous system (CNS) defects potentially involving the glutamine cycle.
• Conflicting evidence exists regarding whether other cell types exhibit similar abnormalities.

Purpose of the Study:

• To investigate the role of the glutamine cycle in non-CNS cells of Huntington's disease patients.
• To assess the impact of L-glutamic acid on fibroblast function in HD.

Main Methods:

• Utilized 30 HD, 20 at-risk, and 20 normal human cell lines.
• Assessed cell viability, plating efficiency, and growth.
• Measured glutamine rescue and incorporation of tritiated thymidine and leucine with varying L-glutamic acid concentrations.

Main Results:

• Decreased cell viability, plating efficiency, and growth were observed with increasing L-glutamic acid concentrations in HD cells.
• Glutamine rescue was significantly less effective in HD cells compared to normal cells.
• HD fibroblasts demonstrated slightly higher sensitivity to L-glutamic acid than normal cells.

Conclusions:

• Fibroblasts from Huntington's disease patients exhibit altered responses to L-glutamic acid, suggesting potential glutamine cycle dysfunction outside the CNS.
• These findings indicate that HD-related cellular abnormalities may extend to peripheral cell types.