胆汁淤积性疾病中低氧诱导因子-2α对心肌营养素-1表达的调节作用

Regulatory Effect of Hypoxia-inducible Factor-2α on Cardiotrophin-1 in Cholestatic Disease

背景:研究显示心肌营养素-1(CT-1)在器官损伤保护以及糖、脂代谢等过程中具有重要调节作用。目的:探讨胆汁淤积性疾病中低氧诱导因子(HIFs)对CT-1表达的调节作用。方法:2016年6月-2017年6月于上海交通大学医学院附属仁济医院招募胆道闭锁患儿23例,7名健康活体肝移植供体作为对照组。以免疫组化法和蛋白质印迹法检测肝组织中的HIF-1α、HIF-2α、CT-1细胞定位和表达。在体外实验中,予人脐静脉内皮细胞(HUVEC)强氧化剂 H2O2处理,并以RNA干扰技术沉默HIF-2α表达,以蛋白质印迹法和real-time PCR检测HIF-2α、CT-1表达变化。结果:在胆汁淤积患儿肝组织中,HIF-2α和CT-1共同分布于胆管细胞以及基质细胞如血管内皮细胞和炎性细胞,HIF-1α仅偶见于炎性细胞。与健康对照者的肝组织相比,胆汁淤积患儿肝组织中HIF-2α、CT-1表达明显升高。 H2O2诱导的氧化应激可显著上调HUVEC HIF-2α、CT-1表达,HIF-2αsiRNA则可在转录水平抑制 H2O2诱导的CT-1表达。结论:在小儿胆汁淤积性疾病中,CT-1表达受HIF-2α而非HIF-1α调节。胆汁淤积进程中的氧化应激中存在HIF-2α依赖性的CT-1表达调节机制。

Background: Cardiotrophin-1( CT-1) is an important regulator of organ protection and glucose and lipid metabolism.Aims: To explore the role of hypoxia-inducible factors( HIFs) in regulating CT-1 expression in cholestatic disease.Methods: Twenty-three pediatric biliary atresia patients and 7 healthy liver donors were enrolled from Jun. 2016 to Jun.2017 at Renji Hospital,School of Medicine,Shanghai Jiao Tong University. Cellular localization and expressions of HIF-1α,HIF-2α and CT-1 in liver tissue were detected by immunohistochemistry and Western blotting. In in vitro study,human umbilical vein endothelial cells( HUVECs) were treated with H2 O2,a strong oxidizer,with or without silencing the expression of HIF-2α with RNA interference,and the expressions of HIF-2α and CT-1 were determined by Western blotting and real-time PCR. Results: In pediatric cholestatic liver tissue,HIF-2α and CT-1 were co-distributed in cholangiocytes and stromal cells such as vascular endothelial cells and inflammatory cells,while HIF-1α was only expressed in some inflammatory cells occasionally. Western blotting showed elevated expressions of HIF-2α and CT-1 in pediatric cholestatic liver tissue when compared with that of healthy controls. H2 O2-induced oxidative stress could significantly increase the expressions of HIF-2α and CT-1 in HUVECs,while silencing of HIF-2α could significantly decrease the transcription of CT-1 induced by H2 O2. Conclusions: HIF-2α but not HIF-1α regulates the expression of CT-1 in pediatric cholestatic disease. In cholestasis,oxidative stress may induce CT-1 expression via HIF-2α-dependent pathway.