MiR-24-3p Conservatively Regulates Muscle Cell Proliferation and Apoptosis by Targeting Common Gene CAMK2B in Rat and Cattle

SIMPLE SUMMARY: MicroRNAs (miRNAs) play important roles in the development of skeletal muscle. Here, a comparative analysis of four skeletal muscle transcriptomes of cattle, rat, goat, and pig showed that miR-24-3p may conservatively regulate muscle development. There is a large proportion of the target genes of miR-24-3p shared by cattle, rat, goat, and pig. GO (Gene ontology) and KEGG (A Kyoto Encyclopedia of Genes and Genomes) enrichment analysis showed that these genes are enriched in multiple cell functions and signal pathways that are closely related to muscle development. In rat and cattle, a double luciferase test showed that three shared target genes, WNT4 (Wnt Family Member 4), CAMK2B (Calcium/Calmodulin Dependent Protein Kinase II Beta), TCF7 (Transcription Factor 7) were targeted by mmu-miR-24-3p and bta-miR-24-3p. The three shared target genes (WNT4, CAMK2B, and TCF7) were all targets in the Wnt signaling pathway, which plays an important role in muscle proliferation in rat and cattle. The shared target gene (CAMK2B) rat was increased significantly after the inhibition of miR-24-3p in rat and cattle. This study will be a good foundation by which to improve our understanding of the functions of miRNAs in the regulation of muscle development. ABSTRACT: Skeletal muscle plays an important role in the growth and development of meat animals. MicroRNAs (miRNAs) can participate in the regulation of muscle development-related functions; however, there have been few reports on whether there are related miRNAs that conservatively regulate muscle development among different species. In this study, the miRNA transcriptome sequencing data of the muscle tissue of cattle, rat, goat, and pig showed that miR-24-3p may conservatively regulate muscle development in these species. Furthermore, mmu-miR-24-3p can positively regulate C2C12 cell proliferation and apoptosis by regulating key proliferation and apoptosis genes in muscle development, which was verified by CCK-8 and RT-qPCR. Bta-miR-24-3p can also positively regulate the proliferation and apoptosis of bovine muscle primary cells by regulating key proliferation and apoptosis genes in the process of muscle development, as verified by CCK-8 and RT-qPCR. The target genes of miR-24-3p in cattle, rat, goat, and pig, which include a large proportion of target genes shared among the four species, are enriched in multiple cell functions and signal pathways that are closely related to muscle development, as revealed by GO and KEGG enrichment analysis. A double luciferase test showed that the shared target genes WNT4, CAMK2B, and TCF7 were targeted by mmu-miR-24-3p in rat and bta-miR-24-3p in cattle. These three shared target genes WNT4, CAMK2B, and TCF7 are involved in the Wnt signaling pathway, which showed that miR-24-3p plays an important role in rat and cattle. The shared target gene (CAMK2B) in rat and cattle increased significantly after the inhibition of miR-24-3p by RT-qPCR. The findings of this study contribute to a better understanding of the role of miR-24-3p in the regulation of muscle development.