PGC-1α Rescues Huntington's Disease Proteotoxicity by Preventing Oxidative Stress and Promoting TFEB Function

Huntington's disease (HD) is caused by CAG repeat expansions in the huntingtin (htt) gene, yielding proteins containing polyglutamine repeats that become misfolded and resist degradation. Previous studies demonstrated that mutant htt interferes with transcriptional programs coordinated by the peroxisome proliferator-activated receptor gamma (PPAR gamma) coactivator 1 alpha (PGC-1 alpha), a regulator of mitochondrial biogenesis and oxidative stress. We tested whether restoration of PGC-1 alpha could ameliorate the symptoms of HD in a mouse model. We found that PGC-1 alpha induction virtually eliminated htt protein aggregation and ameliorated HD neurodegeneration in part by attenuating oxidative stress. PGC-1 alpha promoted htt turnover and the elimination of protein aggregates by activating transcription factor EB (TFEB), a master regulator of the autophagy-lysosome pathway. TFEB alone was capable of reducing htt aggregation and neurotoxicity, placing PGC-1 alpha upstream of TFEB and identifying these two molecules as important therapeutic targets in HD and potentially other neurodegenerative disorders caused by protein misfolding.