Data_Sheet_6_Transcriptome Characterization of Repressed Embryonic Myogenesis Due to Maternal Calorie Restriction.XLS

Fetal malnutrition decreases skeletal myofiber number and muscle mass in neonatal mammals, which increases the risk of developing obesity and diabetes in adult life. However, the associated molecular mechanisms remain unclear. Here, we investigated how the nutrient (calorie) availability affects embryonic myogenesis using a porcine model. Sows were given a normal or calorie restricted diet, following which skeletal muscle was harvested from the fetuses at 35, 55, and 90 days of gestation (dg) and used for histochemical analysis and high-throughput sequencing. We observed abrupt repression of primary myofiber formation following maternal calorie restriction (MCR). Transcriptome profiling of prenatal muscles revealed that critical genes and muscle-specific miRNAs associated with increased proliferation and myoblast differentiation were downregulated during MCR-induced repression of myogenesis. Moreover, we identified several novel miRNA-mRNA interactions through an integrative analysis of their expression profiles, devising a putative molecular network involved in the regulation of myogenesis. Interestingly, NC_010454.3_1179 was identified as a novel myogenic miRNA that can base-pair with sequences in the 3′-UTR of myogenic differentiation protein 1 (MyoD1). And we found that this UTR inhibited the expression of a linked reporter gene encoding a key myogenic regulatory factor, resulting in suppression of myogenesis. Our results greatly increase our understanding of the mechanisms underlying the nutrient-modulated myogenesis, and may also serve as a valuable resource for further investigation of fundamental developmental processes or assist in rational target selection ameliorating repressed myogenesis under fetal malnutrition.

胎儿营养不良会降低新生哺乳动物的骨骼肌肌纤维（skeletal myofiber）数量与肌肉质量，进而增加成年后罹患肥胖与糖尿病的风险。然而，其相关分子机制仍不明确。本研究以猪为动物模型，探究营养素（热量）可获得性对胚胎肌发生的调控作用。实验中给母猪饲喂正常饮食或限热量饮食，随后在妊娠第35、55和90天（dg）采集胎儿骨骼肌样本，用于组织化学分析与高通量测序。我们观察到，母体限热量摄入（MCR）会导致初级肌纤维形成受到显著抑制。产前肌肉组织的转录组分析显示，在MCR介导的肌发生抑制过程中，与成肌细胞增殖、分化相关的关键基因及肌源性microRNA（miRNA）均被下调。此外，通过整合分析二者的表达谱，我们鉴定出多个新型miRNA-mRNA相互作用，构建出参与肌发生调控的推定分子网络。值得注意的是，NC_010454.3_1179被鉴定为一种新型肌源性miRNA，可与肌分化蛋白1（MyoD1）的3'非翻译区（3′-UTR）序列形成碱基配对。我们发现，该3'非翻译区会抑制携带其序列的报告基因的表达，该报告基因编码关键肌源性调节因子，最终导致肌发生受到抑制。本研究结果极大加深了我们对营养素调控肌发生机制的理解，同时可为进一步探究胚胎发育的基础生物学过程，或是为改善胎儿营养不良状态下受抑制的肌发生提供合理的靶点选择依据，是一项极具价值的研究资源。