Cholangiocyte Senescence by Way of N-Ras Activation Is a Characteristic of Primary Sclerosing Cholangitis
Cholangiocyte Senescence by Way of N-Ras Activation Is a Characteristic of Primary Sclerosing Cholangitis
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DOI：
10.1002/hep.26993
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发表时间：
2014-06-01
期刊：
影响因子：
13.5
通讯作者：
LaRusso, Nicholas F.
中科院分区：
文献类型：
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作者：
Tabibian, James H.;O'Hara, Steven P.;LaRusso, Nicholas F.
原发性硬化性胆管炎（PSC）是一种无法治愈的胆管疾病。在这里，我们验证了胆管细胞衰老是PSC的一个重要表型的假设。我们通过荧光原位杂交（FISH）和免疫荧光显微镜（IFM）评估了PSC、原发性胆汁性肝硬化、丙型肝炎患者和正常人肝脏中细胞衰老和衰老相关分泌表型（SASP）的标志物。我们测试了内源性和外源性胆道成分是否影响培养的人胆管细胞的衰老和SASP。我们在共培养中测定衰老胆管细胞是否诱导旁观者胆管细胞衰老。最后，我们探讨了涉及胆管细胞衰老和SASP的信号机制。在体内，与其他三种情况相比，PSC胆管细胞表达更多的衰老相关p16（INK4a）和γ H2A.x；促炎性SASP成分（即IL-6、IL-8、CCL2、PAI-1）在PSC胆管细胞中的表达也最高。在体外，胆汁诱导的胆管细胞衰老和SASP中通常存在几种生物学相关的内源性（如胆甾烷3,5,6氧甾醇）和外源性（如脂多糖）分子。此外，实验诱导的衰老人胆管细胞引起旁观者胆管细胞衰老。已知的衰老诱导剂N-Ras在PSC胆管细胞和实验诱导的培养的衰老胆管细胞中增加；抑制Ras可消除实验诱导的衰老和SASP。结论：胆道成分通过N-Ras活化诱导胆管细胞衰老是PSC的重要致病机制。药物抑制N-Ras从而减少胆管细胞衰老和SASP是治疗PSC的新方法。
Primary sclerosing cholangitis (PSC) is an incurable cholangiopathy of unknown . Here we tested the hypothesis that cholangiocyte senescence is a important phenotype in PSC. We assessed markers of cellular senescence and senescence-associated secretory phenotype (SASP) in livers of patients with PSC, primary biliary cirrhosis, hepatitis C, and in normals by fluorescent in situ hybridization (FISH) and immunofluorescence microscopy (IFM). We tested whether endogenous and exogenous biliary constituents affect senescence and SASP in cultured human cholangiocytes. We determined in coculture whether senescent cholangiocytes induce senescence in bystander cholangiocytes. Finally, we explored signaling mechanisms involved in cholangiocyte senescence and SASP. In vivo, PSC cholangiocytes expressed significantly more senescence-associated p16(INK4a) and gamma H2A.x compared to the other three conditions; expression of profibroinflammatory SASP components (i.e., IL-6, IL-8, CCL2, PAI-1) was also highest in PSC cholangiocytes. In vitro, several biologically relevant endogenous (e.g., cholestane 3,5,6 oxysterol) and exogenous (e.g., lipopolysaccharide) molecules normally present in bile induced cholangiocyte senescence and SASP. Furthermore, experimentally induced senescent human cholangiocytes caused senescence in bystander cholangiocytes. N-Ras, a known inducer of senescence, was increased in PSC cholangiocytes and in experimentally induced senescent cultured cholangiocytes; inhibition of Ras abrogated experimentally induced senescence and SASP. Conclusion: Cholangiocyte senescence induced by biliary constituents by way of N-Ras activation is an important pathogenic mechanism in PSC. Pharmacologic inhibition of N-Ras with a resultant reduction in cholangiocyte senescence and SASP is a new therapeutic approach for PSC.