Epithelial Angiogenic Signaling in Biliary Pathophysiology and in Polycystic Dise

胆道病理生理学和多囊疾病中的上皮血管生成信号传导

• 批准号: 8882404
• 负责人: Mario Strazzabosco
• 金额: $ 36.21万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8882404
• 关键词: Address; Adult; Autosomal Dominant Polycystic Kidney; Biliary; Blood Vessels; Cell Differentiation process; Cells; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyst; Defect; Disease; Disease model; Epithelial; Epithelial Cells; Epithelium; Functional disorder; Funding; Genetic; Goals; Growth; Growth Factor; Health; Homeostasis; Inflammation; Inflammatory; Inherited; Link; Liver; Liver Regeneration; Liver diseases; MAPK3 gene; Mediating; Mesenchymal; Modeling; Morbidity - disease rate; Morphogenesis; Mutate; Mutation; PKD2 protein; Pathogenesis; Pathway interactions; Patients; Physiological; Play; Production; Proliferating; Proprotein Convertase 1; Proteins; Ras/Raf; Regulation; Role; Signal Pathway; Signal Transduction; Stimulus; Testing; Vascular Endothelial Growth Factor Receptor-2; Vascular Endothelial Growth Factors; Work; autocrine; base; cholangiocyte; cytokine; human FRAP1 protein; liver function; liver injury; liver repair; mortality; mouse model; notch protein; novel; paracrine; polycystic liver disease; receptor; repaired; response; stressor

DESCRIPTION (provided by applicant): The long-term goal of our studies is to understand the role of biliary epithelium in the repair and regeneration of the liver after damage. Inherited cholangiopathies with identified genetic defects serve as model diseases to elucidate the fundamental pathophysiological mechanisms. The previously funded proposal focused on polycystic liver disease associated to Adult Dominant Polycystic Kidney Disease (PLD-ADPKD) as a paradigm for the role of angiogenic signaling in biliary diseases. We uncovered mechanisms that may be relevant for the pathogenesis of other congenital and acquired liver diseases. In fact, using mice models with inducible defects of polycystins, we found that: 1) the cystic epithelium produces VEGF and expresses its cognate receptor VEGFR2; 2) VEGF-mediated stimulation of VEGFR2 results in increased ERK1/2-dependent proliferation of the cystic epithelium, 3) PC2-defective cystic cholangiocytes, altered cellular Ca2+ homeostasis and a cAMP- dependent increase in PKA/Ras/Raf/ERK signaling results in mTOR/HIF-1�-mediated stimulation of VEGF production, 4) in response to stimuli able to deplete ER Ca2+ stores, PC2 participates in store-operated Ca2+ entry (SOCE); 5) if PC2 is defective, an alternative pathway is activated (store-operated cAMP production - SOcAMP), leading to an inappropriate overproduction of cAMP; 6) VEGF/VEGFR2 play a key role on cyst growth and expansion through paracrine effects on pericystic vascular cells, and autocrine stimulation of the cystic epithelium proliferation. These findings are the basis of this new proposal which main hypothesis is that the mechanism linking PC2 to VEGF secretion and VEGFR2 expression identified in PLD-ADPKD is of general relevance in biliary pathophysiology. We will address this hypothesis through three specific aims: 1) to better understand the interactions between PC2 function store-operated Ca2+ entry and inappropriate production of cAMP, 2) to study if PC2 expression in WT cholangiocytes can be modulated by cell stressors, thereby reproducing the changes seen in PC2-defective cells; 3) to study the mechanisms leading to VEGFR2 expression in cystic and reactive cholangiocytes, and to elucidate the role of VEGF in the branching morphogenesis of the biliary epithelium during liver repair. These studies will address the novel idea that PC2 play a pivotal role in the regulation of cholangiocyte response to biliary damage acquired cholangiopathies, and that VEGF secreted by reactive cholangiocytes is a major factor in liver repair. Furthermore, our studies will increase understanding of VEGF/VEGFR2 signaling in epithelia and will address a fundamental mechanism in congenital and acquired cholangiopathies. Understanding the pathophysiology of cholangiopathies is a fundamental step for preserving liver function and prolonging the survival of patients

描述(申请人提供)：我们研究的长期目标是了解胆管上皮在肝脏损伤后的修复和再生中的作用。遗传性胆管病具有明显的遗传缺陷，可作为阐明基本病理生理机制的模型疾病。先前资助的提案侧重于与成人遗传性多囊肾病相关的多囊肝(PLD-ADPKD)，作为血管生成信号在胆道疾病中作用的范例。我们发现了可能与其他先天性和获得性肝病的发病机制相关的机制。事实上，利用多囊蛋白可诱导性缺陷的小鼠模型，我们发现：1)囊上皮细胞产生血管内皮生长因子并表达其同源受体VEGFR2；2)血管内皮生长因子2的刺激导致依赖ERK1/2的囊性上皮细胞的增殖增加；3)PC2缺陷的囊性胆管细胞，细胞内钙稳态改变和cAMP依赖性的PKA/RAS/RAF/ERK信号的增加导致mTOR/HIF-1�介导的血管内皮生长因子的产生；5)如果PC2缺陷，另一种途径被激活(商店操作的cAMP产生-SOcAMP)，导致cAMP不适当的过量产生；6)VEGF/VEGFR2通过旁分泌作用于囊周血管细胞，以及自分泌刺激囊性上皮细胞增殖，在囊泡的生长和扩张中发挥关键作用。这些发现是这一新建议的基础，其主要假设是在PLD-ADPKD中发现的PC2与VEGF分泌和VEGFR2表达之间的联系机制在胆道病理生理学中具有普遍意义。我们将通过三个特定的目标来解决这一假说：1)更好地了解PC2功能库操作的钙离子进入和cAMP不适当产生之间的相互作用；2)研究WT胆管细胞中PC2的表达是否可以受到细胞应激源的调节，从而重现PC2缺陷细胞中的变化；3)研究导致囊性和反应性胆管细胞VEGFR2表达的机制，并阐明VEGF在肝修复过程中胆管上皮分支形态发生中的作用。这些研究将阐述PC2在胆管细胞对获得性胆管病的胆道损伤反应中起关键作用的新观点，以及反应性胆管细胞分泌的血管内皮生长因子是肝脏修复的主要因素。此外，我们的研究将增加对上皮细胞中血管内皮生长因子/血管内皮生长因子受体信号的理解，并将解决先天性和获得性胆管疾病的基本机制。了解胆管疾病的病理生理机制是保护肝功能和延长患者生存的根本步骤。