miR-143 regulates proliferation and differentiation of bovine skeletal muscle satellite cells by targeting IGFBP5

Development of skeletal muscle is a complicated biological process regulated by various regulation factors and signal pathways. MicroRNAs (miRNAs) are novel gene regulators that control muscle cell development. microRNA-143 (miR-143) is highly expressed in skeletal muscle, and we found that miR-143 level is significantly increased during bovine skeletal muscle satellite cells (MSCs) differentiation process through microarray analysis and qRT-PCR detection. However, the function of miR-143 in bovine muscle development remained unclear. In our work, the functions of miR-143 in bovine MSCs myogenic differentiation were investigated. We discovered that IGFBP5 is directly regulated by miR-143 using a dual-luciferase reporter assay. Overexpression of miR-143 led to decreased level of IGFBP5 protein and restrained cell proliferation and differentiation, while downregulation of miR-143 resulted in increased levels of IGFBP5 protein and restrained cell proliferation but improved differentiation. IGFBP5, an important component of IGF signaling pathway, contributes greatly to bovine muscle cell development. A mechanism that miR-143 can regulate the proliferation and differentiation of bovine MSCs through changing expression of IGFBP5 was elucidated by our study.