Transcript characteristic of myostatin in sheep fibroblasts

Myostatin, a secreted growth factor highly expressed in skeletal muscle, negatively regulates skeletal muscle growth and differentiation. Recently, myostatin is emerged as a potential target for anti-atrophy and anti-fibrotic therapies. Therefore, to investigate the regulation of myostatin in sheep adult fibroblasts, we used the RNA interference mediated by lentiviral vector to gene silence myostatin. Simultaneously, we also had constructed the sheep myostatin overexpression vector to further explore the function of myostatin in fibroblasts. The results here demonstrated that the lentiviral vector could significantly reduce myostatin gene both at mRNA and protein level by 71% and 67%, respectively (P < 0.01). Inhibition of myostatin also resulted in a remarkable increase of activin receptor 2B (ACV2B), p21, PPARγ, leptin, C/EBPβ, and MEF2A expression, and a decrease of Akt1, CDK2, MEF2C, and Myf5 expression. Ectopic myostatin mRNA and protein were also present in the fibroblasts transfection. Furthermore, we observed that overexpression of myostatin contributed to an increase of Akt1, CDK2, Myf5 and PPARγ, and a decrease of p21, C/EBPα and leptin at the transcript level. These results suggested that myostatin positively regulated Akt1, CDK2, Myf5, leptin, and C/EBPα, but negatively regulated p21 mRNA expression in adult fibroblasts, and it also expanded our understanding of the regulation mechanism of myostatin. Moreover, the lentiviral system inactivated myostatin gene in fibroblasts would be used to generate transgenic sheep and to ameliorate muscle fibrosis and atrophy by gene therapy in the future.