PGC-1α rescues Huntington's disease proteotoxicity by preventing oxidative stress and promoting TFEB function

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Huntington's disease (HD) is a neurodegenerative disorder caused by CAG repeat expansions in the huntingtin (htt) gene.
• Mutant htt protein forms aggregates and disrupts cellular processes, including those regulated by peroxisome proliferator-activated receptor γ (PPARγ) coactivator 1α (PGC-1α).
• PGC-1α is a key regulator of mitochondrial biogenesis and cellular defense against oxidative stress.

Purpose of the Study:

• To investigate whether restoring PGC-1α levels could ameliorate HD symptoms in a mouse model.
• To elucidate the molecular mechanisms by which PGC-1α impacts mutant htt aggregation and neurodegeneration.

Main Methods:

• Utilized a mouse model of Huntington's disease.
• Induced PGC-1α expression to assess its therapeutic effects.
• Analyzed htt protein aggregation, neurodegeneration markers, and oxidative stress levels.
• Investigated the role of transcription factor EB (TFEB) in mediating PGC-1α's effects on the autophagy-lysosome pathway.

Main Results:

• PGC-1α induction significantly reduced htt protein aggregation and ameliorated neurodegeneration in HD mice.
• PGC-1α attenuated oxidative stress, contributing to the observed neuroprotective effects.
• PGC-1α promoted htt turnover and aggregate clearance by activating TFEB, a master regulator of autophagy.
• TFEB activation alone demonstrated the capacity to reduce htt aggregation and neurotoxicity.

Conclusions:

• Restoration of PGC-1α is a promising therapeutic strategy for Huntington's disease.
• The PGC-1α-TFEB axis represents a critical pathway for clearing mutant htt aggregates and mitigating neurotoxicity.
• These findings identify PGC-1α and TFEB as potential therapeutic targets for HD and other protein misfolding neurodegenerative diseases.