The maternal gut microbiota influences myocardial maturation and diastolic function of offspring in mice

Although the maternal microbiome is recognized as a critical regulator of offspring physiology, its role in heart development and the pathogenesis of heart failure remains largely unclear. Using a germ-free (GF) mouse model, we demonstrated that maternal microbiota depletion leads to spontaneous heart failure with preserved ejection fraction (HFpEF) in adult female offspring, recapitulating the phenotypes of human diastolic dysfunction. Integrated transcriptomic and proteomic profiling of fetal hearts revealed impaired structural cardiomyocyte maturation in GF offspring, characterized by suppressed sarcomere assembly. Metabolomic analysis revealed that acetate was concurrently downregulated in maternal serum and fetal cardiomyocytes. Importantly, prenatal acetate supplementation and fecal microbiota transplantation rescued fetal cardiomyocyte maturation defects and prevented the onset of HFpEF in adult female offspring. Mechanistically, maternal microbe-derived acetate regulates fetal cardiomyocyte maturation by enhancing the levels of H3K9ac and H3K27ac in the MYL2 promoter region, thereby promoting the transcriptional enhancement of MYL2. This developmental reprogramming provides lifelong protection against diastolic dysfunction. In addition, the concentration of acetate in pregnant women's serum was positively correlated with myocardial thickness in the left ventricle of the fetus. Our findings establish maternal microbial metabolites as determinants of cardiac maturation and suggest prenatal acetate supplementation as a novel preventive intervention for developmental diastolic dysfunction.