Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, 211 Huiming Road, Wenjiang, Chengdu 611130, China.
Breeding and Genetics Key Laboratory of Sichuan Province, Sichuan Animal Science Academy, 7 Niusha Road, Jinjiang, Chengdu 610066, China.
Genes (Basel). 2021 May 26;12(6):814. doi: 10.3390/genes12060814.
The proliferation and differentiation of skeletal muscle satellite cells (SMSCs) play an important role in the development of skeletal muscle. Our previous sequencing data showed that miR-21-5p is one of the most abundant miRNAs in chicken skeletal muscle. Therefore, in this study, the spatiotemporal expression of miR-21-5p and its effects on skeletal muscle development of chickens were explored using in vitro cultured SMSCs as a model. The results in this study showed that miR-21-5p was highly expressed in the skeletal muscle of chickens. The overexpression of miR-21-5p promoted the proliferation of SMSCs as evidenced by increased cell viability, increased cell number in the proliferative phase, and increased mRNA and protein expression of proliferation markers including PCNA, CDK2, and CCND1. Moreover, it was revealed that miR-21-5p promotes the formation of myotubes by modulating the expression of myogenic markers including MyoG, MyoD, and MyHC, whereas knockdown of miR-21-5p showed the opposite result. Gene prediction and dual fluorescence analysis confirmed that KLF3 was one of the direct target genes of miR-21-5p. We confirmed that, contrary to the function of miR-21-5p, KLF3 plays a negative role in the proliferation and differentiation of SMSCs. Si-KLF3 promotes cell number and proliferation activity, as well as the cell differentiation processes. Our results demonstrated that miR-21-5p promotes the proliferation and differentiation of SMSCs by targeting KLF3. Collectively, the results obtained in this study laid a foundation for exploring the mechanism through which miR-21-5p regulates SMSCs.
骨骼肌卫星细胞（SMSCs）的增殖和分化在骨骼肌的发育中起着重要作用。我们之前的测序数据表明，miR-21-5p 是鸡骨骼肌中最丰富的 miRNA 之一。因此，在这项研究中，我们以体外培养的 SMSCs 为模型，探索了 miR-21-5p 的时空表达及其对鸡骨骼肌发育的影响。本研究结果表明，miR-21-5p 在鸡骨骼肌中高度表达。miR-21-5p 的过表达促进了 SMSCs 的增殖，表现为细胞活力增加、增殖期细胞数量增加以及增殖标志物 PCNA、CDK2 和 CCND1 的 mRNA 和蛋白表达增加。此外，研究还表明，miR-21-5p 通过调节肌生成标志物 MyoG、MyoD 和 MyHC 的表达来促进肌管的形成，而 miR-21-5p 的敲低则表现出相反的结果。基因预测和双荧光分析证实，KLF3 是 miR-21-5p 的一个直接靶基因。我们证实，与 miR-21-5p 的功能相反，KLF3 在 SMSCs 的增殖和分化中发挥负调控作用。Si-KLF3 促进细胞数量和增殖活性以及细胞分化过程。我们的结果表明，miR-21-5p 通过靶向 KLF3 促进 SMSCs 的增殖和分化。综上所述，本研究结果为探索 miR-21-5p 调节 SMSCs 的机制奠定了基础。
