Palmitoleate Protects against Cholangiocyte Lipoapoptosis

该项目的长期目标是确定胆管细胞脂凋亡对 非酒精性脂肪肝(NAFLD)。游离脂肪酸诱导的肝脏细胞凋亡是公认的 肝细胞损伤方面；然而，尚未检测到胆管细胞的凋亡。这个项目将 研究非酒精性脂肪肝的胆管细胞脂凋亡，初步目的是确定临界细胞凋亡 路径和保护策略。初步数据显示，游离脂肪酸诱导表达 促凋亡的miR-34a、c-jun氨基末端激酶(JNK)和培养的胆管细胞的凋亡，以及 棕榈油酸酯发出的信号阻止了脂细胞的凋亡。中心假设是有毒的游离脂肪酸 通过促凋亡的microRNAs和饮食分子棕榈酸酯参与NAFLD的胆道损伤 对胆汁脂类细胞凋亡具有保护作用。其具体目的是：(1)阐明脂细胞凋亡信号转导途径。 胆管细胞在线粒体水平上的调节和棕榈酸酯的缓解；(2)鉴定 游离脂肪酸激活miR-34a的信号通路；以及(3)显示胆管细胞 临床相关肝病中的脂细胞凋亡，并将其与促凋亡的microRNA信号联系起来。一个 将采用高脂饮食诱导的肥胖和肝脏脂肪变性的模型，以及来自 非酒精性脂肪肝患者。饮食棕榈油酸酯或miR-34a基因缺陷对小鼠的保护作用 将会受到考验。这些目标的完成将证明胆管细胞脂凋亡和 MiR-34a在脂肪肝损伤中的作用，为在人类疾病中靶向这种microRNA提供了机会。因此，这一点 项目通过关注临床上相关的细胞死亡途径，具有很强的健康相关性 病人的肝脏。该项目与拟建中心的重点密切相关，即 发现营养物质和生物活性食品化合物预防的信号通路， 改善和治疗肥胖相关疾病，特别是心血管疾病、糖尿病和非酒精性脂肪肝。 通过先进的分子、生物化学和细胞生物学方法操控脂细胞凋亡 和miR-34a，这项研究将为脂肪肝损伤的新的研究方向提供基础，以确定 胆管细胞死亡在疾病中的作用。

The long-term objectives of this project are to determine the contribution of cholangiocyte lipoapoptosis to non-alcoholic fatty liver disease (NAFLD). Free fatty acid-induced apoptosis in the liver is a recognized aspect of hepatocyte injury; however cholangiocyte apoptosis has not been examined. This project will investigate cholangiocyte lipoapoptosis in NAFLD with an initial goal to determine critical apoptosis pathways and protective strategies. Preliminary data demonstrate that free fatty acids induced expression of proapoptotic miR-34a, c-Jun N-terminal kinase (JNK), and apoptosis in cultured cholangiocytes, and that signaling by palmitoleate prevented lipoapoptosis. The central hypothesis is that toxic free fatty acids contribute to biliary injury in NAFLD via proapoptotic microRNAs and the dietary molecule palmitoleate is protective against biliary lipoapoptosis. The specific aims are to: (1) elucidate lipoapoptosis signaling in cholangiocytes regulated at the mitochondrial level and mitigated by palmitoleate; (2) identify the signaling pathway by which free fatty acids activate miR-34a; and (3) demonstrate cholangiocyte lipoapoptosis in clinically relevant liver disease and link this with proapoptotic microRNA signaling. A model of high-fat diet-induced obesity and liver steatosis will be employed, as well as liver samples from patients with NAFLD. Protection by dietary palmitoleate or genetic deficiency of miR-34a in the mouse will be tested. Completion of these aims will demonstrate the role of cholangiocyte lipoapoptosis and miR-34a in fatty liver injury, providing an opportunity to target this microRNA in human disease. Thus, this project has strong health relatedness by focusing on the clinically relevant cell death pathways present in the liver of patients. The project is closely related to the focus of the proposed Center, which is the discovery of signaling pathways through which nutrients and bioactive food compounds prevent, ameliorate, and treat obesity-related diseases, particulariy cardiovascular disease, diabetes, and NAFLD. Through advanced molecular, biochemical, and cell biological approaches to manipulate lipoapoptosis and miR-34a, this study will provide a foundation for a new line of inquiry in fatty liver injury to define the role of biliary cell death in disease.