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: 8725137
• 负责人: Reena Rao
• 金额: $ 32.84万
• 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/8725137
• 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.

描述(申请人提供)：糖原合成酶激酶3(GSK3)是一个丝氨酸/苏氨酸蛋白激酶家族，由两种异构体组成，GSK3a和GSK3？在肾脏中，已知GSK3？调节细胞分化和正常的上皮功能。尽管体内外证据表明锂，一种治疗双相情感障碍的常用疗法和GSK3的有效抑制剂，可以减少肾脏对加压素的反应，但GSK3在肾脏水运输中的作用尚不清楚。我们在锂诱导的多尿小鼠模型和集合管特异性GSK3基因敲除小鼠中的观察表明，GSK3通过调节水通道蛋白2的表达来响应加压素，在肾水重吸收中发挥重要作用。在GSK3基因敲除小鼠中，腺苷环化酶活性和cAMP水平以一种未知的机制降低，这可能导致水通道蛋白2的低表达和对加压素的运输反应。根据这些证据，我们推测GSK3在肾脏水平衡中起着关键作用。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)第一个目的是通过定点突变检测GSK3是否与腺苷环化酶结合或磷酸化腺苷环化酶来确定GSK3如何调节腺苷环化酶的活性。2)AVP信号激活GSK3的机制将通过检验AVP信号通过抑制典型的Wnt信号而激活GSK3的假说来确定。蛋白激酶A可能调节GSK3的负反馈回路也将被研究。3)第三个目的将检验AVP抵抗-锂诱导的NDI是肾脏GSK3抑制的病理生理结果的假说。由于AVP信号的增加和cAMP水平的升高促进了多囊肾病的进展，这一目的也将检验GSK3的抑制或基因缺失可以减少囊变的假设。这些研究将利用野生型和集合管特异性GSK3基因敲除小鼠、原代培养的内髓集合管细胞和小鼠皮质集合管细胞。通过这些研究，我们试图确定GSK3调节肾集合管内AVP信号的机制及其生理和病理生理学意义。