Cell-cell adhesion-mediated signaling determines epithelial polarization in the liver

细胞间粘附介导的信号传导决定肝脏中的上皮极化

• 批准号: 10446638
• 负责人: ANNE MUESCH
• 金额: $ 40万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-04 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10446638
• 关键词: Apical; Architecture; Back; Bile Acids; Bile fluid; Binding; Biogenesis; Blood; Blood Coagulation Factor; Blood Vessels; Blood capillaries; Cell membrane; Cell-Cell Adhesion; Cells; Cyclic AMP-Dependent Protein Kinases; Cytokeratin; Data; Development; Duct (organ) structure; Ductal Epithelial Cell; Engineering; Ensure; Epithelial; Epithelial Cells; Excretory function; Gastrointestinal tract structure; Gatekeeping; Glycogen; Hepatic Tissue; Hepatocyte; In Vitro; Intestines; Knowledge; Length; Lipids; Liver; Liver Fibrosis; Liver diseases; Measures; Mediating; Membrane; Membrane Protein Traffic; Metabolic; Modeling; Modification; Molecular; Morphology; Organ; Phenotype; Phosphorylation; Phosphotransferases; Physiological; Population; Proteins; Protocols documentation; Regulation; Resistance; Rest; Role; Running; Scaffolding Protein; Side; Signal Transduction; Signaling Protein; Structure; Substrate Specificity; Surface; System; Testing; Tissue Stains; Toxicology; Transplantation; Tubular formation; Update; Xenobiotics; apical membrane; bile canaliculus structure; bile duct; blood filter; cell type; constriction; gene therapy; interstitial; mutant; neglect; programs; rho; sensor; tissue culture; trafficking; venule

NOTE: You must submit in Word format, not PDF, for eRA to update all the systems. The liver is our largest metabolic organ. It produces proteins, lipids, clotting factors and glycogen while dispensing bile and detoxifying xenobiotics. In order to transport these different substances, a sophisticated network of liver venules, capillaries and interstitial conduits has evolved. An essential feature of this network are the lumen-forming epithelia that give rise to two major liver cell populations: (1) hepatocytes - the main parenchymal cell type, and (2) bile duct cells. Both acquire radically different polarity phenotypes adapted to their different functions (Fig.1): Bile duct cells, which form simple conduits for bile, organize like other tubular epithelia around a central lumen. Hepatocytes, by contrast form single-cell cords, aligned along blood vessels on either side and with a capillary-like luminal network (bile canaliculi) running between them. This organization facilitates their extensive bi-directional molecular exchange with the blood, while allowing bile acid excretion into the bile canaliculi. How hepatocytes obtain this unique morphological phenotype is poorly understood. Indeed, because bile canaliculi are not visible by conventional H&E tissue stain, the study of hepatocyte polarity has largely been neglected. The resulting gap in our knowledge has greatly hindered our ability to better understand the molecular basis of common liver diseases, which typically present with changes in hepatocyte polarity and morphology. It also severely limits our ongoing efforts to engineer hepatic tissue that can be used for transplantation, toxicology and gene therapy studies. To tackle these issues, we developed a unique tissue culture model in which the polarity phenotype can be switched from ductal to hepatocytic and utilized it to identify molecular mechanisms that distinguish the hepatocytic from the ductal polarization program. In parallel, we developed protocols to in vitro differentiate polarized hepatocytes from their precursors and evaluated proteins critical for the hepatocytic polarity switch in these physiological relevant systems. This led to the discovery of the dual PKA-anchoring and Rho-activating protein AKAP13 as regulator of bile canaliculi elongation. Elucidating the mechanisms underlying its function, as proposed here, will reveal a critical morphological mechanisms of hepatocyte polarization.

注：您必须以Word格式提交，而不是PDF格式，以便eRA更新所有系统。 肝脏是我们最大的代谢器官。它产生蛋白质，脂质，凝血因子和糖原，同时分配胆汁和解毒异生物质。为了运输这些不同的物质，已经进化出复杂的肝小静脉、毛细血管和间质管道网络。该网络的一个基本特征是形成管腔的上皮细胞，其产生两种主要的肝细胞群：（1）肝细胞-主要的实质细胞类型，和（2）胆管细胞。两者都获得了完全不同的极性表型，以适应其不同的功能（图1）：胆管细胞，形成胆汁的简单管道，像其他管状上皮细胞一样围绕中央管腔组织。相反，肝细胞形成单细胞索，沿着两侧的血管沿着排列，其间有毛细血管样的管腔网络（胆小管）。这种组织有利于它们与血液进行广泛的双向分子交换，同时允许胆汁酸排泄到胆小管中。肝细胞如何获得这种独特的形态表型知之甚少。事实上，由于传统的H&E组织染色法看不到胆小管，因此肝细胞极性的研究在很大程度上被忽视了。由此产生的知识差距极大地阻碍了我们更好地了解常见肝脏疾病的分子基础的能力，这些疾病通常表现为肝细胞极性和形态的变化。它也严重限制了我们正在进行的工程肝组织，可用于移植，毒理学和基因治疗研究的努力。 为了解决这些问题，我们开发了一种独特的组织培养模型，其中极性表型可以从导管切换到肝细胞，并利用它来识别区分肝细胞和导管极化程序的分子机制。与此同时，我们开发了在体外分化极化肝细胞从他们的前体和评估的蛋白质在这些生理相关的系统中的肝细胞极性开关的关键协议。这导致了PKA锚定和Rho激活双重蛋白AKAP 13作为胆小管伸长调节因子的发现。阐明其功能的机制，如本文所提出的，将揭示肝细胞极化的关键形态学机制。