B34 Mitochondrial Biogenesis, And Respiratory Chain Assembly And Function, In Heart Of R6/2 Mouse Model Of Huntington's Disease

Abstract

Background Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG-repeat mutation in the HTT gene. Apart from the known clinical symptoms of HD the underlying cause of death is unknown. Some evidence suggests that heart disease is involved in death in HD patients. While the involvement of the heart in human HD has not been investigated extensively, in the R6/2 HD mouse model some data suggest mitochondrial involvement. Aims In heart of R6/2 mice mitochondria appeared smaller and had abnormal shapes in heart tissue compared with controls. We investigated if mitochondrial biogenesis, including respiratory chain assembly and function, is affected in heart of the R6/2 HD model. Methods/techniques We used heart tissues of 12 week old R6/2 mice with 160 CAG repeats to assess different aspects of mitochondrial biology e.g. mitochondrial biogenesis, and mitochondrial respiratory chain assembly and function. Results We analysed the activity and the assembly of the respiratory chain complexes. Moreover, we examined PGC-1α, which is a transcriptional coactivator involved, among other things, in the induction of mitochondrial biogenesis. We investigated its downstream target TFAM, a regulator for the transcription of mitochondrial DNA and determined the mitochondrial DNA copy number.