Role of caspase‐9 in the effector caspases and genome expressions,and growth of bovine skeletal myoblasts

Caspase‐9 has been reported as the key regulator of apoptosis, however, its role in skeletal myoblast development and molecular involvements during cell growth still remains unknown. The current study aimed to present the key role of caspase‐9 in the expressions of apoptotic caspases and genome, and cell viability during myoblast growth using RNA interference mediated silencing. Three small interference RNA sequences (siRNAs) targeting caspase‐9 gene was designed and ligated into pSilencer plasmid vector to construct shRNA expression constructs. Cells were transfected with the constructs for 48 h. Results indicated that all three siRNAs could silence the caspase‐9 mRNA expression significantly. Particularly, the mRNA expression level of caspase‐9 in the cells transfected by shRNA1, shRNA2 and shRNA3 constructs were reduced by 37.85%, 68.20% and 58.14%, respectively. Suppression of caspase‐9 led to the significant increases in the mRNA and protein expressions of effector caspase‐3, whereas the reduction in mRNA and protein expressions of caspase‐7. The microarray results showed that the suppression of caspase‐9 resulted in significant upregulations of cell proliferation‐, adhesion‐, growth‐, development‐ and division‐regulating genes, whereas the reduction in the expressions of cell death program‐ and stress response‐regulating genes. Furthermore, cell viability was significantly increased following the transfection. These data suggest that caspase‐9 could play an important role in the control of cell growth, and knockdown of caspase‐9 may have genuine potential in the treatment of skeletal muscle atrophy.