LncRNA H19 in Cholestatic Liver Diseases

胆管病，如原发性胆汁性肝硬变(PBC)和原发性硬化性胆管炎(PSC)， 以胆管上皮细胞(胆管细胞)的损伤和功能障碍为特征。最近，长时间的非编码 RNAs(LncRNAs)已被确定为一类新的基因表达的主要调控因子，并与 对许多基本的生物过程和各种人类疾病，包括各种肝病。 然而，关于lncRNAs在调节胆管细胞功能和 肝胆疾病的发病机制。当前应用程序的总体目标是确定角色和 LncRNAs在胆汁淤积条件下胆汁功能障碍中的作用机制 为胆管病开发新的治疗策略。LncRNAs的表达是组织、细胞类型的- 和分化阶段特异性。LncRNA h19是第一个被鉴定的印迹lncRNA，高度保守。 跨越血统。据报道，H19是在肝脏中差异表达最强的lncrna。 它与一系列人类癌症和胆汁淤积性肝转移有关 受伤。然而，H19在胆管细胞病理生理中的调节作用尚不清楚，目前仍是研究的焦点。 当前应用程序的。我们最新的研究发现，H19在胆管细胞中高度表达， 而不是在生理条件下的肝细胞中，而肝脏H19的表达水平与 多药耐药2基因敲除(MDR2-/-)小鼠S1PR2表达上调与淤胆性肝损伤 建立PSC小鼠模型和PSC患者肝脏模型。我们的初步数据进一步表明：1)BDL 显著上调H19，下调心尖胆汁酸转运体(ASBT)和 牛磺胆酸钠共转运多肽(NTCP)；2)BDL所致的淤胆性肝损伤明显 在H19Δ外显子1/+小鼠中减少；3)击倒H19不仅显著降低牛磺胆酸(Tca)- 诱导肝纤维化基因和S1PR2在胆管细胞中的表达，但也明显上调肝小管上皮细胞 异二聚体伙伴(SHP)的表达与mdr2-/-小鼠的胆汁淤积损伤；4)肝脏H19水平 在四氯化碳(CCl4)诱导的胆汁淤积性肝损伤小鼠模型中也有显著上调。 基于这些观察，我们推测lncrna h19在调控中起重要作用。 通过破坏肝脏胆汁酸平衡来影响肝胆上皮功能。两个具体目标是 提出用来检验这一假说。1)明确lncRNAH19在胆汁酸介导的胆汁酸调节中的作用 胆汁淤积性肝损伤时胆管细胞的生长和重塑；2)探讨其作用机制 哪些胆汁酸在胆汁淤积条件下上调lncRNAH19。建议的研究完成后， 通过连接lncRNA H19介导的胆管上皮调控取得重大概念性进展 胆管病患者胆汁淤积性损伤的功能，并将提供翻译机制 胆汁酸和lncRNAH19如何介导肝胆纤维化。

Cholangiopathies, such as primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), are characterized by damage and dysfunction of bile duct epithelial cells (cholangiocytes). Recently, long noncoding RNAs (lncRNAs) have been identified as a novel class of master regulators of gene expression and are linked to many fundamental biological processes and various human diseases including various liver diseases. However, little is known regarding the role of lncRNAs in the regulation of cholangiocyte function and pathogenesis of hepatobiliary diseases. The overall goal of the current application is to identify the roles and mechanisms of lncRNAs in biliary dysfunction under cholestatic conditions and to create a fundamental base for developing novel therapeutic strategies for cholangiopathies. The expression of lncRNAs is tissue-, cell type- and differentiation stage-specific. LncRNA H19 is the first identified imprinted lncRNA and is highly conserved across lineages. It has been reported that H19 is the most strongly differentially expressed lncRNA during liver development and has been linked to hepatic metastases from a range of human carcinomas and cholestatic liver injury. However, the regulatory role of H19 in cholangiocyte pathophysiology remains unknown and is the focus of the current application. Our most recent studies discovered that H19 is highly expressed in cholangiocytes, but not in hepatocytes under physiological conditions and hepatic H19 expression levels are correlated with upregulation of S1PR2 and cholestatic liver injury in the multi-drug resistance 2 knockout (Mdr2-/-) mouse, a well- established mouse model of PSC and PSC patient liver. Our preliminary data further showed that 1) BDL significantly up-regulated H19 and down-regulated the apical sodium bile acid transporter (ASBT) and sodium/taurocholate co-transporting polypeptide (NTCP); 2) BDL-induced cholestatic liver injury was markedly reduced in H19ΔExon1/+ mouse; 3) Knocking down H19 not only significantly reduced taurocholate (TCA)- induced expression of fibrotic genes and S1PR2 in cholangiocytes, but also markedly upregulated hepatic small heterodimer partner (SHP) expression and reduced cholestatic injury in Mdr2-/- mice; 4) Hepatic H19 level was also significant upregulated in the carbon tetrachloride (CCl4)-induced cholestatic liver injury mouse model. Based on these observations, we HYPOTHESIZE that lncRNA H19 plays an important role in the regulation of hepatobiliary epithelial function by disruption of hepatic bile acid homeostasis. Two specific aims are proposed to test this hypothesis. 1) To define the role of lncRNA H19 in the regulation of bile acid-mediated cholangiocyte growth and remodeling during cholestatic liver injury; 2) To identify the mechanisms by which bile acids upregulate lncRNA H19 in cholestatic conditions. Completion of the proposed studies will make a significant conceptual advance by linking the lncRNA H19-mediated regulation of biliary epithelial function with cholestatic biliary injury in patients with cholangiopathies and will provide a translational mechanism for how bile acids and lncRNA H19 mediate hepatobiliary fibrosis.