HIF-1α上调Mfn1的表达促进线粒体融合在宫缩维持中的机制研究

The mechanism of HIF-1αup-regulating the expression of Mfn1 to promote mitochondrial fusion in the maintenance of uterine contraction

目的 检测线粒体融合蛋白Mfn1在临产前后的表达,探讨其与HIF-1α参与维持子宫收缩的分子机制。方法 选取2018年5至10月于广州市妇女儿童医疗中心行子宫下段剖宫产术患者的部分肌条组织。依据患者手术前是否临产分为未临产组(即无宫缩、无产兆行择期剖宫产,共12例)和临产组(有规律宫缩,处于潜伏期,总产程<8 h,除外胎膜早破,共12例)。透射电镜观察两组患者子宫平滑肌组织中线粒体融合现象,RT-PCR和Western blot法检测Mfn1、HIF-1α和AMPK的表达水平。构建不同低氧时间体外短暂低氧子宫平滑肌细胞收缩模型,观察Mfn1、HIF-1α和AMPK的表达情况。使用HIF-1α抑制剂2-MeOE2处理细胞,Western blot法检测低氧处理后AMPK和Mfn1蛋白表达情况。采用试剂盒测定细胞内脂肪酸和ATP含量,细胞收缩实验测定细胞收缩力。结果 与未临产组相比,临产组子宫平滑肌组织内线粒体融合增加,Mfn1、HIF-1α和AMPK的表达明显上升(P<0.05)。体外细胞模型短暂低氧2 h HIF-1α、AMPK和Mfn1表达增加最显著(P<0.05),细胞内脂肪酸及ATP含量亦显著增加。与未抑制HIF-1α表达细胞相比,抑制HIF-1α表达可明显下调AMPK和Mfn1蛋白表达(P<0.01),抑制细胞收缩。结论 临产后人体子宫平滑肌Mfn1显著增加,HIF-1α可能通过AMPK通路调节Mfn1表达,参与细胞能量供应和子宫收缩的维持。

Objective To detect the expression of mitochondrial fusion protein Mfn1 before and after labor and explore the molecular mechanism of its participation in maintaining uterine contraction with HIF-1α.Methods Partial myometrium of patients who underwent lower segment cesarean section at Guangzhou Women and Children's Medical Center from May to October 2018 was selected.Patients were divided into two groups according to whether they were in labor before surgery:the non-labor group(12 cases with no uterine contractions or signs of labor,undergoing elective cesarean section)and the labor group(12 cases with regular uterine contractions,in the latent period,total labor duration<8 hours,except for premature rupture of membrane).Mitochondrial fusion was observed in myometrium of two groups of patients with transmission electron microscopy.Mfn1,HIF-1αand AMPK expression levels were detected by RT-PCR and Western blot.Observed the expression of Mfn1,HIF-1αand AMPK by constructing the contraction model of uterine smooth muscle cells under transient hypoxia in vitro for different hypoxia time.After the cells were treated with HIF-1αinhibitor 2-MeOE2,Western blot was used to detect the expression of AMPK and Mfn1 protein after hypoxia treatment.The contents of free fatty acid and ATP in cells were measured by kit,and the contractility of cells was measured by cell contraction assay.Results Compared with non-labor group,the mitochondrial fusion in the myometrium increased in labor group,and the expression of Mfn1,HIF-1αand AMPK was significantly increased(P<0.05).The expression of HIF-1α,AMPK and Mfn1 in vitro cell model under transient hypoxia for 2 hours increased most significantly(P<0.05),and the content of free fatty acid and ATP in cells also increased significantly.Compared with cells without 2-MeOE2,inhibition of HIF-1αexpression significantly decreased the expression of AMPK and Mfn1 protein(P<0.01)and inhibited cell contraction.Conclusion After labor,Mfn1 in human myometrium significantly increases.HIF-1αmay upregulate the expression of Mfn1 through AMPK pathway,and participate in the maintenance of cell energy supply and uterine contraction.