Haughton Emma L, Tucker Steven J, Marek Carylyn J, Durward Elaine, Leel Val, Bascal Zainab, Monaghan Tanya, Koruth Matthew, Collie-Duguid Elaina, Mann Derek A, Trim Julie E, Wright Matthew C
School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland.
Gastroenterology. 2006 Jul;131(1):194-209. doi: 10.1053/j.gastro.2006.04.012.
BACKGROUND & AIMS: The activated pregnane X receptor is antifibrogenic in rodent chronic liver injury in vivo models. The aim of this study was to determine the effects of human pregnane X receptor activators on human hepatic stellate cell transdifferentiation to a profibrogenic phenotype in vitro.
Hepatic stellate cells were isolated from resected human liver and cultured under conditions in which they trans-differentiate into profibrogenic myofibroblasts.
The pregnane X receptor was expressed in primary cultures at the level of messenger RNA and protein and was activated by the ligand rifampicin as judged by increases in binding of proteins to the pregnane X receptor ER6 DNA response element and by increases in ER6-dependent reporter gene expression. Short-term treatment of hepatic stellate cells with rifampicin inhibited the expression of selected fibrosis-related genes (transforming growth factor beta1, alpha-smooth muscle actin), proliferation-related genes, and WNT signaling-associated genes. There was also an increase in interleukin-6 secretion and an inhibition in DNA synthesis. Long-term treatment with rifampicin over several weeks reduced the proliferation and transdifferentiation of hepatic stellate cells. Small interfering RNA knockdown of the pregnane X receptor in a hepatic stellate cell line reduced the binding of proteins to the ER6 DNA response element and abrogated pregnane X receptor activator-dependent changes in transforming growth factor beta1 expression, interleukin-6 secretion, and proliferation.
The pregnane X receptor is transcriptionally functional in human hepatic stellate cells and activators inhibit transdifferentiation and proliferation. The pregnane X receptor may therefore be an effective target for antifibrotic therapy.
在啮齿动物慢性肝损伤体内模型中，活化的孕烷X受体具有抗纤维化作用。本研究旨在确定人孕烷X受体激活剂对人肝星状细胞体外转分化为促纤维化表型的影响。
从切除的人肝脏中分离肝星状细胞，并在使其转分化为促纤维化肌成纤维细胞的条件下进行培养。
孕烷X受体在原代培养物中以信使核糖核酸和蛋白质水平表达，并被配体利福平激活，这可通过蛋白质与孕烷X受体ER6 DNA反应元件结合增加以及ER6依赖性报告基因表达增加来判断。用利福平短期处理肝星状细胞可抑制所选纤维化相关基因（转化生长因子β1、α-平滑肌肌动蛋白）、增殖相关基因和WNT信号相关基因的表达。白细胞介素-6分泌也增加，DNA合成受到抑制。用利福平进行数周的长期处理可减少肝星状细胞的增殖和转分化。在肝星状细胞系中用小干扰RNA敲低孕烷X受体可减少蛋白质与ER6 DNA反应元件的结合，并消除孕烷X受体激活剂依赖性的转化生长因子β1表达、白细胞介素-6分泌和增殖变化。
孕烷X受体在人肝星状细胞中具有转录功能，其激活剂可抑制转分化和增殖。因此，孕烷X受体可能是抗纤维化治疗有效的靶点。
