Maternal obesity affects MicroRNA expression in fetal muscle at mid‐gestation

Abstract

INTRODUCTIONObesity is increasing at an alarming rate. Previous findings in our laboratory have shown that maternal obesity leads to increased adipogenesis in fetal muscle. Expression of adipogenic genes lead to adipogenesis. MicroRNAs play a crucial role in the regulation of gene expression. Using the pregnant sheep as a model, the objective was to assess microRNA expression in fetal muscle due to maternal obesity.METHODSNon pregnant ewes were randomly assigned to a control (Con, 100% of NRC recommendations, n = 5) or obesogenic (OB, 150% of NRC, n = 5) diet from 60 days before to 75 days after conception, when fetal longissimus dorsi (Ld) muscle was collected. MicroRNAs were extracted, purified and subjected to microRNA microarray analyses using the known microRNAs from human, rat, mouse and cattle.RESULTS67 microRNAs were identified in fetal LD muscle based on the generation of strong hybridization signals. Among those, 3 microRNAs, including hsa‐miR‐381, hsa‐let‐7g and bta‐miR‐376d, were differentially expressed between the Con and OB groups, which was confirmed by real‐time quantitative PCR. Hsa‐miR‐381 was 51.7 ± 17.3% higher (P < 0.05) in the OB fetal muscle compared to Con, while Hsa‐let‐7g (21.5 ± 4.9% (P = 0.06) and Bta‐miR‐376d (26.0 ± 8.8% (P < 0.05) were lower.CONCLUSIONMaternal obesity induced differential expression of microRNAs in fetal LD muscle. Since microRNAs regulate gene expression, changes in microRNA expression potentially play important roles in the development of fetal muscle, including adipogenesis, in the setting of maternal obesity. (Supported by NIH 1R03HD057506 and Wyoming INBRE P20RR016474)