High fat diet ameliorates the mitochondrial cardiomyopathy of CHCHD10 mutant mice.

Mutations in CHCHD10, a mitochondrial protein with still undefined function, are associated with dominant multi-system mitochondrial diseases. CHCHD10 knock-in mice harboring a heterozygous S55L mutation (equivalent to the human pathogenic S59L mutation) develop a fatal mitochondrial cardiomyopathy. The heart of S55L knock-in mice shows extensive metabolic rewiring triggered by proteotoxic mitochondrial integrated stress response (mtISR). In the mutant heart, mtISR initiates well before the onset of mild bioenergetic impairments and is associated with a shift from fatty acid oxidation to glycolytic metabolism and widespread metabolic imbalance. We tested therapeutic interventions to counteract the metabolic rewiring and ameliorate the metabolic imbalance. Heterozygous S55L mice were subjected to chronic high fat diet (HFD) to decrease insulin sensitivity and glucose uptake and enhance fatty acid utilization in the heart. Metabolomics and gene expression profiles demonstrated that HFD achieved an increase of fatty acid utilization in the heart accompanied by a decrease in cardiomyopathy markers. Surprisingly, HFD also decreased the accumulation of aggregated CHCHD10 in the S55L heart. Importantly, HFD increased the survival of mutant female mice exposed to acceleration of the mitochondrial cardiomyopathy associated with pregnancy. Our findings indicate that metabolic alterations can be effectively targeted for therapeutic intervention in mitochondrial cardiomyopathies associated with proteotoxic stress.