The role of PGC-1α in the pathogenesis of neurodegenerative disorders.

Mitochondrial dysfunction is a common hallmark of ageing-related diseases involving neurodegeneration. Huntington's disease (HD) is one of the most common monogenetic forms of neurodegenerative disorders and shares many salient features with the major sporadic disease of neurodegeneration, such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD). Recent evidence from the study of transgenic and knockout animal models of HD has stimulated new perspectives on mitochondrial dysfunction in HD and possibly other neurodegenerative diseases. The transcriptional co-activator PGC-1α, originally described as a metabolic master regulator in peripheral tissues such as brown adipose tissue (BAT) and muscle, has emerged as a molecular link between transcriptional dysregulation and mitochondrial dysfunction in the brain. PGC-1α knockout mice display many phenotypic similarities to transgenic mouse models of HD and the gene-expression analysis of tissues from HD patients revealed a disruption of the PGC-1α regulatory pathway. Hence, mitochondrial and transcriptional dysregulation in HD - previously thought to be unrelated mechanisms of neurodegeneration - appear to be directly linked at the molecular level. The clinical and therapeutic potential of targeting the PGC-1α in HD is further highlighted by the finding that common genetic variations in the PGC-1α gene significantly modify the disease onset, delaying the onset of motor symptoms by several years. The present review provides an overview of the advances in the understanding of the role of the PGC-1α system in HD pathogenesis and explores the implications for ALS, AD and PD.