ALK4-Smad2/3信号通路在特发性肺纤维化中的作用及机制研究

The Effect and Mechanism of ALK4-Smad2/3 Signaling Pathway in Idiopathic Pulmonary Fibrosis

目的:探讨ALK4对肺纤维化的作用及其机制。方法:野生型(ALK4~(+/+))小鼠和ALK4~(+/-)小鼠分别分为生理盐水组(对照组)及博来霉素模型组(实验组),使用HE及Masson两种染色观察肺纤维化程度,使用Western印迹检测ALK4、p-Smad2、p-Smad3及t-Smad2/3的蛋白表达水平,使用RT-qPCR检测CollagenⅠ、Fibronectin、α-SMA的mRNA表达水平,独立样本t检验统计实验数据。结果:ALK4在博来霉素诱导的肺纤维化组织中表达水平显著升高(P<0.05);低表达ALK4抑制了博来霉素诱导的肺纤维化;博来霉素诱导的肺纤维化小鼠中ALK4~(+/-)组CollagenⅠ、Fibronectin、α-SMA的mRNA表达明显低于ALK4~(+/+)组(P<0.05);博来霉素诱导的肺纤维化小鼠中ALK4~(+/-)组的p-Smad2、p-Smad3表达水平均显著低于ALK4~(+/+)组(P<0.05)。结论:下调ALK4表达可以抑制Smad2/3信号传导,进而抑制肺间质纤维化的形成,因此ALK4可能成为特发性肺纤维化的潜在治疗靶点。

Objective:To investigate the effect and mechanism of ALK4 on pulmonary fibrosis.Methods:The ALK4+/+mice and ALK4+/-mice were divided into normal saline group(control group)and bleomycin model group(experimental group),respectively.The degree of pulmonary fibrosis was observed by HE and Masson staining.The protein expression levels of ALK4,p-Smad2,p-Smad3 and t-Smad2/3 were detected by Western blotting.And the mRNA expression levels of CollagenⅠ,Fibronectin,α-SMA were detected by RT-qPCR.Independent sample t-test was used to measure the experimental data.Results:The expression of ALK4 in bleomycin-induced pulmonary fibrosis group was significantly increased(P<0.05).Low expression of ALK4 cloud inhibite bleomycin induced pulmonary fibrosis.In bleomycin-induced pulmonary fibrosis mice,the mRNA expression of of CollagenⅠ,Fibronectin andα-SMA in ALK4+/-group was significantly lower than those in ALK4+/+group(P<0.05).In bleomycin-induced pulmonary fibrosis mice group,the expression levels of p-Smad2 and p-Smad3 in ALK4+/-group were significantly lower than those in ALK4+/+group(P<0.05).Conclusion:Our data suggest that ALK4 acts as a novel regulator of pulmonary fibrosis via the negative regulation of Smad2/3 Signaling pathway and may serve as a potential therapeutic target for idiopathic pulmonary fibrosis.