Changes of gene expression in skeletal muscle cells after co-culture of bovine skeletal muscle cells and intramuscular fat cells

The growth and lipid accumulation of skeletal muscle directly affect the yield and meat quality of beef, which is the result of the interaction between skeletal muscle cells (SMCs) and intramuscular fat cells (IMAs). In the process of myogenesis, IMAs not only has the function of energy storage, but also can regulate the function of SMCs by releasing signal molecules or secretory factors. Our team used a co-culture system to simulate the cell microenvironment in vivo, aiming to reveal the interaction mode between bovine SMCs and IMAs in the stages of proliferation and differentiation. The results showed that the presence of IMAs in the co-culture system inhibited the expression of proliferation markers such as PCNA, CDK1, CDK2, CCNA2 and CCNE2 in SMCs compared with SMCs cultured alone. This also affects the G1/S phase transition of SMCs, thus inhibiting its proliferation rate. At the same time, the presence of IMAs also inhibits the expression of myogenic markers such as MYHC, MYOD, MYOG, MYF5 and MYF6, thus hindering the myotube formation process of SMCs. On this basis, our team further added RNA-seq to screen the differentially expressed genes in SMCs.