Maternal obesity suppresses embryonic myogenesis via enhancing H19 lncRNA expression

Background: Maternal obesity (MO) impairs fetal skeletal muscle development, which programs long-term metabolic dysfunction of offspring muscle, but the underlying mechanisms remain poorly defined. Gene imprinting is an allelic epigenetic modification derived from gametes, resulting in gene expression only from one parental allele. H19, the first discovered imprinting gene, is a paternally imprinted and maternally expressed long non-coding long RNA (lncRNA). H19 is highly expressed in placental and fetal tissues but rapidly downregulated after birth except skeletal muscle, underscoring its roles in regulating muscle development. Up to now, the regulatory roles of H19 in prenatal myogenesis and muscle development affected by MO remain to be examined. We hypothesized that MO suppresses embryonic myogenesis by altering H19 expression. Method: High-fat diet (45% calories from the fat) was used to induce MO in mice. Briefly, total 32 of C57BL/6 mice (8-week-old) were randomly chosen and divided into control (CT, chow diet, n=16) and MO (n=16) groups. After 2-month feeding, female mice were mated with age-matched males. Successful mating was confirmed by the presence of vaginal plug. Embryos were collected at E11.5. To analyze allelic expression, CAST/EiJ mice were crossed with C57BL/6, which resulted in 8 single nucleotide polymorphisms (SNPs) between two alleles at the H19 gene. Single cell-RNA sequencing (scRNA-seq) was conducted using E11.5 embryos. To analyze its mediatory role, H19 was overexpressed in P19 cells and the resulting myogenesis was analyzed. Results: MO mice were 23% heavier than the CT group. MO embryos displayed suppressed muscle development, shown by reduced myogenic genes expression. Both scRNA-seq and RT-qPCR showed that H19 expression was increased in MO embryos. The imprinting pattern of H19 was disrupted, showing a bi-allelic expression of H19. To establish causality, we overexpressed H19 in cells which strongly inhibited myogenesis, indicated by lower myogenic genes expression and less myotube formation. Conclusion: MO impedes embryonic myogenesis by elevating H19 expression. The imprinting of H19 in the paternal allele was disrupted by MO, resulted in H19 expression from both maternal and paternal alleles. R01HD067449 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.