Male obesity causes adipose mitochondrial dysfunction in F₁ mouse progeny via a let-7-DICER axis

Male obesity negative affects gametic function and offspring metabolism. We here describe that (F₀) obesity and weight loss in male mice reversibly alter metabolism and impair adipose mitochondrial function. These metabolic aberrations are transmitted to male offsprings (F₁), which display reduced mitochondrial gene expression. Mechanistically, we identify microRNAs let-7d/e as epigenetic mediators induced in obese F₀ sperm and in F₀/F₁ adipose tissue, where they silence the miRNA processor DICER1 and impair mitochondrial activity. Microinjecting let-7d/e into lean zygotes phenocopies the paternal obesity phenotype, inducing glucose intolerance and mitochondrial gene suppression in sired offspring. Single-cell RNA sequencing of blastomeres reveals that let-7d/e impair oxidative metabolism in early embryos. Furthermore, lifestyle-induced weight loss in males with obesity downregulates human HSA-LET-7D/E in semen, indicating a conserved role for let-7 in transmission of metabolic health. These findings demonstrate that microRNA let-7 in sperm reprograms offspring metabolism by modulating mitochondrial function during early development.