Mitochondrial Dysfunction, Metabolic Deficits, and Increased Oxidative Stress in Huntington’s Disease

Huntington’s disease (HD) is an autosomal dominant, progressiveneurodegenerative disorder, characterized by an arrayof different psychiatric manifestations, cognitive decline andchoreiform movements. The underlying molecular geneticdefect is an expanded trinucleotide (CAG)n repeat encoding apolyglutamine stretch in the N-terminus of the huntingtin protein.The mechanisms by which mutant huntingtin causes neuronaldysfunction and degeneration are not fully understood.Nevertheless, impaired ubiquitin-proteasome activity, defectiveautophagy-lysosomal function, transcriptional dysregulation,oxidative stress, apoptosis, mitochondrial and metabolicdysfunction, and abnormal protein-protein interaction havebeen shown to play important roles in the pathogenesis of HD.Neurons are energy-demanding and more susceptible to energeticfailure and oxidative damage than other types of cell.Given that mitochondria play a central role in both processes of metabolism and oxidativestress, and increasing direct evidence shows mitochondrial abnormalities in both HD mousemodels and patients, this article will review the studies of mitochondrial dysfunction, metabolicdeficits, and increased oxidative stress in HD, and discuss the potential therapeuticstargeting these abnormalities.