Liver Injury and Cancer Program, Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, NSW 2050, Australia; Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Camperdown, NSW 2050, Australia.
Liver Injury and Cancer Program, Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, NSW 2050, Australia.
Biochim Biophys Acta Mol Basis Dis. 2022 Apr 1;1868(4):166335. doi: 10.1016/j.bbadis.2021.166335. Epub 2021 Dec 30.
BACKGROUND & AIMS: Loss of primary cilia in epithelial cells is known to cause cystic diseases of the liver and kidney. We have previously shown that during experimental and human cirrhosis that primary cilia were predominantly expressed on biliary cells in the ductular reaction. However, the role of primary cilia in the pathogenesis of the ductular reaction is not fully understood.
Primary cilia were specifically removed in biliary epithelial cells (BECs) by the administration of tamoxifen to Kif3a;CK19 mice at week 2 of a 20-week course of TAA treatment. Biliary progenitor cells were isolated and grown as organoids from gallbladders. Cells and tissue were analysed using histology, immunohistochemistry and Western blot assays.
At the end of 20 weeks TAA administration, primary cilia loss in liver BECs resulted in multiple microscopic cystic lesions within an unaltered ductular reaction. These were not seen in control mice who did not receive TAA. There was no effect of biliary primary cilia loss on the development of cirrhosis. Increased cellular proliferation was seen within the cystic structures associated with a decrease in hepatocyte lobular proliferation. Loss of primary cilia within biliary organoids was initially associated with reduced cell passage survival but this inhibitory effect was diminished in later passages. ERK but not WNT signalling was enhanced in primary cilia loss-induced cystic lesions in vivo and its inhibition reduced the expansion of primary cilia deficient biliary progenitor cells in vitro.
TAA-treated kif3a BEC-specific knockout mice had an unaltered progression to cirrhosis, but developed cystic lesions that showed increased proliferation.
已知上皮细胞中初级纤毛的丧失会导致肝脏和肾脏的囊性疾病。我们之前已经表明，在实验性和人类肝硬化中，初级纤毛主要在上皮细胞的胆管反应中的胆管细胞上表达。然而，初级纤毛在胆管反应发病机制中的作用尚不完全清楚。
通过在 20 周的 TAA 治疗的第 2 周向 Kif3a;CK19 小鼠施用他莫昔芬，特异性去除胆管上皮细胞（BEC）中的初级纤毛。从胆囊中分离和培养胆管祖细胞作为类器官。使用组织学、免疫组织化学和 Western blot 分析来分析细胞和组织。
在 TAA 给药 20 周结束时，肝脏 BEC 中的初级纤毛丧失导致在未改变的胆管反应中出现多个微小的囊性病变。在未接受 TAA 的对照小鼠中未观察到这些病变。胆管初级纤毛丧失对肝硬化的发展没有影响。与肝小叶增殖减少相关的囊性结构中观察到细胞增殖增加。胆管类器官中初级纤毛的丧失最初与细胞通过存活率降低有关，但这种抑制作用在后期通过时会减弱。ERK 但不是 WNT 信号在体内初级纤毛丧失诱导的囊性病变中增强，其抑制作用减少了体外缺乏初级纤毛的胆管祖细胞的扩增。
接受 TAA 治疗的 kif3a BEC 特异性敲除小鼠进展为肝硬化没有改变，但发展为囊性病变，显示出增殖增加。
