Maternal Obesity Leads to Muscle Dysfunction via H19-Mediated Programming of Insulin-Like Growth Factor 2 Signaling.

Forty-two percent of American women of childbearing age have obesity, impacting offspring muscle and metabolism. The insulin-like growth factor 2 (IGF2) pathway is vital for muscle growth, but its regulation by maternal obesity (MO) remains unclear. H19, a long noncoding RNA, is reciprocally regulated with Igf2, which has multiple promoters (P0–P3). H19 interacts with EZH2, the catalytic subunit of polycomb repressive complex 2 depositing H3K27me3. We found that MO increased fetal H19 expression and investigated how H19 epigenetically regulates Igf2 in offspring muscle. C57BL/6J female mice were fed a control (10% fat) or high-fat diet (45% fat) to induce obesity before mating, continuing through pregnancy and lactation. Neonates were sampled for biochemical analysis, and 3-month-old offspring were used for assessing muscle function and metabolism. MO increased H19 expression, enhancing H19-EZH2 interaction and H3K27me3-mediated repression of Igf2 in the P3 promoter, leading to hypermethylation and impaired muscle function in offspring. In addition, offspring with myogenic cell-specific H19 overexpression were also used. Weaning offspring with H19 overexpression showed reduced muscle mass, strength, and endurance and altered structure. Primary myogenic cells from H19 overexpressing neonates showed suppressed Igf2 expression, promoter activity, and myotube formation, which were recovered upon IGF2 treatment. In C2C12 and human skeletal myoblast cells, H19 overexpression disrupted IGF2 signaling, increased EZH2 recruitment, and reduced myotube formation, while its knockdown had opposite effects. Additionally, EZH2 inhibition reduced H3K27me3 deposition and methylation in the Igf2 P3 promoter. These data show that MO impairs muscle development by disrupting IGF2 signaling through H19-EZH2 interaction, affecting offspring muscle function. ARTICLE HIGHLIGHTS: H19-mediated epigenetic modifications alter Igf2 promoter activity, leading to persistent Igf2 suppression in maternal obesity (MO) offspring, causing long-term muscle dysfunction. MO increases H19 expression and enhances EZH2 recruitment and H3K27me3 deposition in the Igf2 P3 promoter, leading to higher DNA methylation. H19-EZH2 axis provides a potential therapeutic target for mitigating MO-induced muscle dysfunction and improving offspring metabolic health.