利拉鲁肽通过激活CAMKK2/AMPK通路促进骨骼肌FNDC5的表达

目的:探讨利拉鲁肽(LG)对骨骼肌细胞Ⅲ型纤连蛋白结构域包含蛋白5(fibronectin typeⅢdomain-containing protein 5,FNDC5)表达水平的影响并探讨其机制。方法:小鼠成肌细胞系C2C12经诱导分化后,给予梯度浓度(1~1 000 nmol/L)LG处理不同时间(0~24 h),观察LG对FNDC5表达及磷酸化腺苷酸活化蛋白激酶(adenosine 5'-monophosphate-activated protein kinase,AMPK)信号通路活性的影响,以及应用胰高血糖素样肽1(glucagon-like peptide-1,GLP-1)受体拮抗剂exendin_(9-39)、钙/钙调素依赖的蛋白激酶激酶2(Ca~(2+)/calmodulin-dependent protein kinase kinase 2,CAMKK2)的抑制剂STO609或AMPK的抑制剂Compound C预处理C2C12肌管细胞,观察FNDC5蛋白表达的改变。AMPK的活性及FNDC5的表达用Western blot法检测。结果:LG能够促进C2C12骨骼肌细胞FNDC5的蛋白表达,并具有剂量及时间依赖性,同时激活AMPK。LG的上述作用可被exendin_(9-39)、STO609或Compound C阻断。结论:利拉鲁肽可促进C2C12小鼠骨骼肌细胞合成FNDC5,此作用依赖于GLP-1受体,可能是通过激活CAMKK2/AMPK信号通路实现的。

Liraglutide increases FNDC5 expression in C2C12 myotubes via activation of CAMKK2/AMPK signaling pathways

AIM: To investigate the effect of liraglutide (LG) on the expression of fibronectin type Ⅲ domain-containing protein 5 (FNDC5) in the C2C12 myotubes. METHODS: The C2C12 mouse myoblast cell line was induced to differentiation. Differentiated cells were stimulated with gradient concentrations (1~1 000 nmol/L) of LG for different time (0~24 h). The effects of LG on the expression of FNDC5 and the activation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway were determined. After pretreated with glucagon-like peptide-1 (GLP-1) receptor antagonist exendin_9-39, the inhibitor of Ca²⁺/calmodulin-dependent protein kinase kinase 2 (CAMKK2), STO609, or the inhibitor of AMPK, Compound C, the LG-induced FNDC5 expression in C2C12 myotubes was examined. The expression of FNDC5 and the activation of AMPK were determined by Western blot. RESULTS: In C2C12 myotubes, LG promoted the expression of FNDC5 in a dose- and time-dependent manner. LG also activated AMPK signaling pathway. These effects of LG were partly abolished by exendin_9-39, STO609 and Compound C. CONCLUSION: LG promotes the expression of FNDC5 via GLP-1 receptor in the C2C12 myotubes possibly through activation of the CAMKK2/AMPK signaling pathways.