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: 8926130
• 负责人: Reena Rao
• 金额: $ 8.46万
• 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/8926130
• 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（由申请人提供）：糖原合成酶激酶3 （GSK3）是一个丝氨酸/苏氨酸蛋白激酶家族，由两个异构体GSK3a和GSK3 α组成。在肾脏中，已知GSK3能够调节细胞分化和正常上皮功能。尽管体外和体内证据表明，锂是双相情感障碍的一种常见疗法，也是一种有效的GSK3 -抑制剂，可以降低肾脏对抗利尿激素的反应，但GSK3 -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和收集管特异性GSK3基因敲除小鼠中观察到，GSK3基因通过调节水通道蛋白2的表达来响应抗利尿激素，在肾脏水重吸收中发挥重要作用。在GSK3基因敲除小鼠中，腺苷酸环化酶活性和cAMP水平由于一种未知的机制而降低，这可能导致水通道蛋白2在抗利尿激素作用下的低表达和低运输。基于这些证据，我们假设GSK3在肾脏水稳态中起关键作用。该激酶在正常肾水重吸收中的作用将在以下3个目的中确定。1)第一个目标是通过检测GSK3是否与腺苷酸环化酶结合或使用位点定向诱变使腺苷酸环化酶磷酸化，从而确定GSK3如何调节腺苷酸环化酶活性。2)通过验证AVP信号通过抑制典型Wnt信号激活GSK3的假设，确定AVP信号激活GSK3的机制。蛋白激酶A可能调节GSK3的负反馈回路也将被研究。3)第三个目的将验证AVP耐药锂诱导的NDI是肾脏GSK3抑制的病理生理后果的假设。由于AVP信号的增加和高cAMP水平有助于多囊肾病的进展，本研究也将验证GSK3的抑制或基因缺失可以减少囊发生的假设。这些研究将利用野生型和收集管特异性GSK3基因敲除小鼠、髓内收集管细胞和小鼠皮质收集管细胞的原代培养。通过这些研究，我们试图确定GSK3调控肾集管AVP信号的机制及其生理和病理生理意义。