The Role of PGC-1α in Neurodegenerative Diseases: Molecular Mechanisms, Translational Challenges, and Therapeutic Potential.

Neurodegenerative diseases (NDDs) are progressive disorders in which mitochondrial dysfunction, oxidative stress, proteostasis failure, neuroinflammation, and synaptic damage progressively interact to drive neuronal vulnerability. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) links metabolic adaptation to stress-response pathways that are repeatedly disrupted in Alzheimer's disease, Parkinson's disease, Huntington's disease, polyglutamine (PolyQ) disorders, and amyotrophic lateral sclerosis. Rather than providing only an updated catalogue of studies, this review organizes the evidence into a cross-disease rheostat framework that explains why PGC-1α modulation is protective in some settings but incomplete or maladaptive in others. Current findings indicate that PGC-1α supports mitochondrial biogenesis, oxidative phosphorylation, antioxidant defense, mitophagy, autophagy, protein quality control, and inflammatory balance. However, its effects are highly context dependent. In several models, restoration of PGC-1α-related signaling improves mitochondrial function and reduces neuronal injury, whereas broad, sustained, or cell-inappropriate activation may produce limited benefit or undesirable outcomes. These observations suggest that PGC-1α is not a simple neuroprotective switch, but a flexible regulatory hub whose therapeutic value depends on cell type, isoform profile, disease stage, and activation level. Emerging strategies, including small-molecule modulators, gene delivery, antisense-based approaches, nanoparticle systems, and exercise-related interventions, remain largely preclinical and face major barriers related to CNS delivery, pathway selectivity, dose and cell-type control, peripheral safety, and validated target-engagement biomarkers. Nevertheless, clinical translation requires stronger causal validation, reliable target-engagement biomarkers, selective delivery methods, and long-term safety assessment. Future research should focus on precision-based modulation of PGC-1α to determine when and how this pathway can be safely used for disease modification. Such a careful approach may help transform PGC-1α from a broad experimental target into a clinically relevant strategy for well-defined neurodegenerative phenotypes.