Regulation of Renal Response to Vasopressin by Glycogen Synthase

糖原合酶调节肾脏对加压素的反应

• 批准号: 8042365
• 负责人: Reena Rao
• 金额: $ 37.75万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-20 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8042365
• 关键词: Adenylate Cyclase; Amino Acids; Binding; Bipolar Disorder; Cell Differentiation process; Cells; Cirrhosis; Congestive Heart Failure; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Disease; Disease Progression; Duct (organ) structure; Epithelial; Equilibrium; Experimental Water Deprivation; Family; Feedback; Gene Deletion; Generations; Glycogen (Starch) Synthase; Glycogen Synthase Kinase 3; Goals; Homeostasis; In Vitro; Investigation; Kidney; Knockout Mice; Lead; Lithium; Mediating; Mus; Nephrogenic Diabetes Insipidus; Neurohormones; Phosphorylation; Phosphotransferases; Physiological; Plasma; Play; Polycystic Kidney Diseases; Protein Isoforms; Protein-Serine-Threonine Kinases; Regulation; Resistance; Role; Signal Transduction; Site; Site-Directed Mutagenesis; Testing; Vasopressins; Water; Wild Type Mouse; analog; apical membrane; aquaporin-2; base; in vivo; inhibitor/antagonist; mouse model; response; trafficking; urinary; water channel

DESCRIPTION (provided by applicant): Glycogen synthase kinase 3 (GSK3) is a family of serine/threonine protein kinases that consists of two isoforms, GSK3a and GSK3¿. In the kidney, GSK3¿ is known to regulate cell differentiation and normal epithelial function. Despite in vitro and in vivo evidence that lithium, a common therapy for bipolar disorders and a potent inhibitor of GSK3¿ can reduce renal response to vasopressin, the role of GSK3¿ in renal water transport is not clear. Our observations in the lithium induced polyuric mouse model as well as collecting duct specific GSK3¿ knockout mice showed that GSK3¿ plays a significant role in renal water reabsorption by regulating aquaporin 2 expression in response to vasopressin. In the GSK3¿ knockout mice, adenylate cyclase activity and cAMP levels were reduced by an undetermined mechanism, which could have led to low aquaporin 2 expression and trafficking in response to vasopressin. Based on these evidences we hypothesize that GSK3¿ plays a critical role in renal water homeostasis. The role of this kinase in normal renal water reabsorption will be determined in the following 3 aims. 1) The first aim will determine how GSK3 regulates adenylate cyclase activity by examining if GSK3 binds to or phosphorylates adenylate cyclase using site directed mutagenesis. 2) The mechanism by which AVP signaling activates GSK3 will be determined by testing the hypothesis that AVP signaling activates GSK3 by inhibiting the canonical Wnt signaling. A negative feedback loop by which protein kinase A might regulate GSK3 will also be examined. 3) The third aim will test the hypothesis that AVP resistant- lithium induced NDI is a pathophysiological consequence of inhibition of renal GSK3. Since increased AVP signaling and high cAMP levels contribute to the progression of polycystic kidney disease, this aim will also test the hypothesis that inhibition or gene deletion of GSK3 can reduce cystogenesis. These studies will utilize wild type and collecting duct specific GSK3¿ knockout mice, primary cultures of inner medullary collecting duct cells and mouse cortical collecting duct cells. Through these studies we exoect to identify the mechanism by which GSK3 regulates AVP signaling in the renal collecting duct and its physiological and pathophysiological significance. PUBLIC HEALTH RELEVANCE: The goal of the current study is to examine the role of glycogen synthase kinase 3 (GSK3) in the regulation of vasopressin mediated water reabsorption in the renal collecting duct. These studies will utilize collecting duct specific GSK3¿ knockout mice and GSK3 inhibitors to examine the mechanism by which GSK3¿ regulates adenylate cyclase activity and the pathophysiological significance of such a regulation.

描述（由申请人提供）：糖原合成酶激酶3（GSK 3）是丝氨酸/苏氨酸蛋白激酶家族，由两种亚型GSK 3 α和GSK 3？组成。在肾脏中，已知GSK 3 <$调节细胞分化和正常上皮功能。尽管有体外和体内证据表明锂（双相情感障碍的常用疗法和GSK 3 <$的强效抑制剂）可以降低肾脏对加压素的反应，但GSK 3 <$在肾脏水转运中的作用尚不清楚。我们在锂诱导的多尿小鼠模型以及集合管特异性GSK 3 <$$>基因敲除小鼠中的观察表明，GSK 3 <$通过调节水通道蛋白2的表达在肾脏水重吸收中起着重要作用。在GSK 3中，在敲除小鼠中，腺苷酸环化酶活性和cAMP水平通过未确定的机制降低，这可能导致水通道蛋白2的低表达和对加压素的响应的运输。基于这些证据，我们假设GSK 3在肾脏水平衡中起关键作用。该激酶在正常肾脏水重吸收中的作用将在以下3个目标中确定。1)第一个目标将确定GSK 3如何调节腺苷酸环化酶活性，通过检查GSK 3是否结合或磷酸化腺苷酸环化酶使用定点诱变。2)AVP信号传导激活GSK 3的机制将通过检验AVP信号传导通过抑制经典Wnt信号传导激活GSK 3的假设来确定。一个负反馈回路，蛋白激酶A可能调节GSK 3也将被检查。3)第三个目的是检验AVP抗性-锂诱导的NDI是肾GSK 3抑制的病理生理学结果的假设。由于增加的AVP信号传导和高cAMP水平有助于多囊肾疾病的进展，因此该目的还将测试GSK 3的抑制或基因缺失可以减少囊肿形成的假设。这些研究将利用野生型和集合管特异性GSK 3？敲除小鼠、内髓集合管细胞和小鼠皮质集合管细胞的原代培养物。通过这些研究，我们期望确定GSK 3调节肾集合管AVP信号的机制及其生理和病理生理意义。 公共卫生关系：本研究的目的是探讨糖原合成酶激酶3（GSK 3）在加压素介导的肾集合管水重吸收调节中的作用。这些研究将利用收集管特异性GSK 3 <$敲除小鼠和GSK 3抑制剂来检查GSK 3 <$调节腺苷酸环化酶活性的机制以及这种调节的病理生理学意义。