Sustained AMPK activation improves muscle function in a mitochondrial myopathy mouse model by promoting muscle fiber regeneration

Abstract

Acute pharmacological activation of adenosinemonophosphate (AMP)-kinase using 5-aminoimidazole-4-carboxamide-1-b-Dribofuranoside (AICAR) has been shown to improvemusclemitochondrial function by increasingmitochondrial biogenesis.We asked whether prolonged AICAR treatment is beneficial in amousemodel of slowly progressingmitochondrialmyopathy (Cox10-Mef2c-Cre), and whether the compensatorymechanismis indeed an increase inmitochondrial biogenesis.We treated the animals for 3months and found that sustained AMP-dependent kinase activation improved cytochrome c oxidase activity, rescued themotor phenotype and delayed the onset of themyopathy. This improvement was observed whether treatment started before or after the onset of the disease.We found that AICAR increased skeletalmuscle regeneration thereby decreasing the levels of deleted Cox10-floxed alleles.We conclude that although increase inmitochondrial biogenesis and other pathwaysmay contribute, themainmechanismby which AICAR improves themyopathy phenotype is by promotingmuscle regeneration.