oar‐miR‐411a‐5p Promotes Proliferation and Differentiation in Hu Sheep Myoblasts Under Heat Stress by Targeting SMAD2

Abstract

MicroRNAs (miRNAs) are endogenous noncoding RNAs that produce a remarked effect on regulating posttranscriptional gene expression. Our previous study identified a decrease in the expression of oar‐miR‐411a‐5p from umbilical plasma in intrauterine growth restriction (IUGR) Hu lambs subjected to maternal heat stress. In this study, we demonstrated that oar‐miR‐411a‐5p could modulate skeletal muscle development. Overexpression of oar‐miR‐411a‐5p significantly enhanced proliferation and differentiation in heat‐stressed Hu sheep myoblasts while suppressing apoptosis. Conversely, inhibition of oar‐miR‐411a‐5p resulted in opposing effects. Subsequently, RNAhybrid analysis revealed targeted sites between oar‐miR‐411a‐5p and the 3′ untranslated region (UTR) of SMAD2. This suggested that SMAD2 is a direct target gene of oar‐miR‐411a‐5p, as its expression was negatively modulated by oar‐miR‐411a‐5p, a finding corroborated by dual‐luciferase assay and RT‐qPCR. Furthermore, co‐transfection of oar‐miR‐411a‐5p and SMAD2 into Hu sheep myoblasts indicated that oar‐miR‐411a‐5p modulated heat‐stressed myoblast growth by targeting SMAD2. In conclusion, these findings elucidate the function of oar‐miR‐411a‐5p in promoting the development of heat‐stressed Hu sheep myoblasts, thereby enhancing our understanding of how miRNAs influence skeletal muscle growth in heat‐stressed Hu sheep.