Role of adenylyl cyclase isoforms in collecting duct physiology & pathophysiology

腺苷酸环化酶亚型在集合管生理学中的作用

• 批准号: 8895765
• 负责人: Donald E Kohan
• 金额: $ 32.42万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8895765
• 关键词: A Mouse; Adenylate Cyclase; Affect; Animals; Autosomal Dominant Polycystic Kidney; Biochemistry; Bladder Control; Blood Pressure; Cells; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyst; Cystic Kidney Diseases; Data; Development; Disease; Duct (organ) structure; Endocrine; Engineering; Excretory function; Figs - dietary; Functional disorder; Genes; Health; Hypertension; Individual; Kidney; Knock-out; Mediating; Metabolism; Modality; Mus; Pathogenesis; Pathway interactions; Physiological; Physiology; Play; Polycystic Kidney Diseases; Production; Protein Isoforms; Proteins; Regulation; Research Design; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Sodium; Structure; Therapeutic; Vasopressins; Water; autocrine; base; blood pressure regulation; cell water; design; in vivo; inhibitor/antagonist; interest; loss of function; mouse model; novel; paracrine; phosphoric diester hydrolase; polycystic kidney disease 1 protein; pressure; public health relevance; urinary

DESCRIPTION (provided by applicant): The collecting duct principal cell (PC) is responsible for the final adjustment of renal Na and water excretion. Derangements in PC Na reabsorption are associated with most forms of monogenic hypertension, while altered PC water transport accompanies disorders of water metabolism. PC Na and water transport are subject to the influences of multiple autocrine, paracrine and endocrine factors. A key mechanism for mediating many of these effects involves signaling through adenylyl cyclase (AC)-derived cAMP. The PC expresses AC3, 4 and 6, raising the fundamental question as to which biologic effects individual AC isoforms exert in the PC. We have engineered mice with PC-specific disruption of AC3, 4 or 6, and have found exciting new evidence for unique roles of the PC AC isoforms, AC3 and 6. Our findings suggest that AC6 regulates PC Na and water transport, while AC3 selectively affects PC water transport. Based on these novel findings, together with the currently increasing interest in designing inhibitors specific for individual AC isoforms as therapeutic modalities, this proposal will define the role of the specific AC isoforms, AC3 and 6 in the regulation of PC Na and water transport. In addition, cAMP in the PC is not only important in regulating Na and water transport, but it can be of primary importance in disease. In particular, disordered cAMP production and actions in autosomal dominant polycystic kidney disease play a fundamental role in cyst development and expansion. In preliminary studies, we have obtained exciting new data suggesting that targeting AC6 is markedly protective against the development of cystic kidney disease in a mouse model. Consequently, this proposal will define the role of specific AC isoforms in the PC in the pathogenesis of polycystic kidney disease. The major hypotheses of this proposal are: 1) AC3 and 6 in the PC exert distinctive effects on PC Na and water transport in health; and 2) AC3 and 6 in the PC differentially modulate PC development into cysts in polycystic kidney disease. The proposal has three specific aims: 1) Aim 1 will determine the physiologic role of PC AC isoforms (AC3 and 6) in renal Na and water handling. Each AC isoform will be selectively targeted in mouse PC in vivo. Intact animals and acutely isolated collecting ducts will be used to assess the role of the individual AC isoforms by loss of function in the regulation of blood pressure and Na and water excretion. 2) Aim 2 will determine the biochemistry of PC AC isoforms (AC3 and 6) related to control of cAMP levels and cAMP effects on Na and water transport. The mechanisms by which individual AC isoform-derived cAMP is modulated by vasopressin and exerts its biologic effects will be studied using mice with PC-specific knockout of AC3, 6 or both isoforms. In particular, these studies will define how cAMP derived from each AC isoform in the PC is metabolized by phosphodiesterases and which signaling molecules (protein kinase A and/or exchange protein directly activated by cAMP) are directly activated by each AC isoform in transducing vasopressin actions in the PC. 3) Aim 3 will determine the pathophysiologic effects of all PC AC isoforms (AC3 and 6) in polycystic kidney disease. A mouse model of polycystin-1 deficiency will be employed and the effect of simultaneously disrupting individual AC isoforms together with the Pkd1 gene on renal structure and function will be assessed. These studies will define which AC isoform(s) is/are important in the pathogenesis of polycystic kidney disease and will begin to identify the specific signaling pathways that individual AC isoforms modulate in polycystic kidney disease.

描述（申请人提供）：集合管主细胞（PC）负责肾钠和水排泄的最终调节。 PC Na 重吸收紊乱与大多数形式的单基因高血压有关，而 PC 水转运的改变则伴随着水代谢紊乱。 PC Na和水的运输受到多种自分泌、旁分泌和内分泌因素的影响。介导许多这些效应的关键机制涉及通过腺苷酸环化酶 (AC) 衍生的 cAMP 发出信号。 PC 表达 AC3、4 和 6，这就提出了一个基本问题：各个 AC 亚型在 PC 中发挥哪些生物效应。我们对小鼠进行了 PC 特异性破坏 AC3、4 或 6 的改造，并发现了关于 PC AC 亚型、AC3 和 6 独特作用的令人兴奋的新证据。我们的研究结果表明，AC6 调节 PC Na 和水的运输，而 AC3 选择性地调节 PC Na 和水的转运。影响PC水的运输。基于这些新发现，加上目前对设计针对单个 AC 异构体​​作为治疗方式的特异性抑制剂的兴趣日益浓厚，该提案将定义特定 AC 异构体​​、AC3 和 6 在 PC Na 和水转运调节中的作用。此外，PC 中的 cAMP 不仅在调节钠和水的运输方面很重要，而且在疾病中也起着至关重要的作用。特别是，常染色体显性多囊肾病中 cAMP 产生和作用紊乱在囊肿的发育和扩张中发挥着重要作用。在初步研究中，我们获得了令人兴奋的新数据，表明靶向 AC6 可显着预防小鼠模型中囊性肾病的发展。因此，该提案将定义 PC 中特定 AC 亚型在多囊肾发病机制中的作用。该提案的主要假设是：1）PC中的AC3和6对健康中的PC Na和水运输具有独特的影响； 2) PC 中的 AC3 和 6 差异调节多囊肾病中 PC 发育成囊肿。该提案具有三个具体目标：1) 目标 1 将确定 PC AC 亚型（AC3 和 6）在肾钠和水处理中的生理作用。每种 AC 亚型将选择性地靶向小鼠 PC 体内。完整的动物和急性分离的集合管将用于评估个体 AC 亚型在血压调节和钠和水排泄方面功能丧失的作用。 2) 目标 2 将确定与 cAMP 水平控制以及 cAMP 对 Na 和水运输的影响相关的 PC AC 亚型（AC3 和 6）的生物化学。将使用 PC 特异性敲除 AC3、6 或两种同工型的小鼠来研究个体 AC 亚型衍生的 cAMP 受加压素调节并发挥其生物效应的机制。特别是，这些研究将定义来自 PC 中每种 AC 亚型的 cAMP 如何被磷酸二酯酶代谢，以及哪些信号分子（蛋白激酶 A 和/或由 cAMP 直接激活的交换蛋白）在转导加压素作用中被每种 AC 亚型直接激活在电脑中。 3) 目标 3 将确定所有 PC AC 亚型（AC3 和 6）在多囊肾病中的病理生理学作用。将采用多囊蛋白-1缺乏症的小鼠模型，并评估同时破坏单个AC亚型和Pkd1基因对肾脏结构和功能的影响。这些研究将确定哪些 AC 同工型在多囊肾病的发病机制中很重要，并将开始确定各个 AC 同工型在多囊肾病中调节的特定信号传导途径。