Bone morphogenetic protein-7 negatively regulates insulin signal transduction in C2C12 myotubes and HepG2 hepatocytes

Objective To investigate the effects of bone morphogenetic protein-7(BMP7) on insulin signaling transduction in C2C12 myotubes and HepG2 hepatocytes, and the underlying mechanisms were studied preliminarily. Methods The C2C12 myotubes and HepG2 cells were treated with BMP7 at different concentrations. The insulin signal transduction was analyzed by Western blot. Meanwhile, total RNA was extracted and quantitative PCR was employed for detecting the effects of BMP7 on gene expressions of effectors involved in insulin signal pathway. Furthermore, JNK signal pathway was also measured. Results The protein levels of p-IR, p-Akt and p-GSK3β, as well as glucose uptake, were significantly stimulated by insulin in the C2C12 myotubes and HepG2 cells. However, these stimulations induced by insulin were largely attenuated by BMP7. The mRNA levels of Akt1, Igf1r, Insr, and Irs1 were not altered by the treatment of BMP7. The JNK signal pathway was activated by a 5-min exposure of BMP7 in the HepG2 cells, and this activation was gradually reduced along with the treating time. Conclusion BMP7 attenuates the insulin signal transduction in the HepG2 cells and C2C12 myotubes, and this attenuation effect may be through JNK activation. (Chin J Endocrinol Metab, 2016, 32: 128-132) Key words: Bone morphogenetic protein-7; Insulin signal transduction; Glucose