STAT Regulation by Polycystin-1

Polycystin-1 的 STAT 调节

• 批准号: 7989215
• 负责人: Thomas Weimbs
• 金额: $ 10.69万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-18 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7989215
• 关键词: Acute; Affect; Alleles; Animal Experiments; Animal Model; Animals; Apical; Automobile Driving; Autosomal Dominant Polycystic Kidney; Binding; Biological Preservation; Cell Line; Cell Nucleus; Cells; Chronic; Cilia; Clinical Trials; Cyst; Cystic Kidney Diseases; Cystic kidney; Cytokine Signaling; Cytoplasmic Tail; Data; Dialysis procedure; Disease Progression; Doxycycline; Drug Delivery Systems; Embryo; End stage renal failure; Epithelial; Epithelial Cells; FDA approved; Future; Gene Expression; Genes; Growth; Healthcare Systems; Hereditary Disease; Human; Immune; Immune system; Injury; Interleukin-13; Interleukin-4; Kidney; Kidney Failure; Kidney Transplantation; Knockout Mice; Knowledge; Leflunomide; Life; Light; MDCK cell; Measures; Membrane; Modeling; Molecular; Mutation; Nuclear; Nuclear Translocation; Onset of illness; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Phosphotransferases; Play; Property; Proteins; Quality of life; Regulation; Renal function; Reperfusion Injury; Reporter; Rheumatoid Arthritis; Role; STAT6 Transcription Factor; STAT6 gene; Signal Pathway; Signal Transduction; Sirolimus; Staging; Tail; Testing; Time; Tissues; Transgenic Mice; Tubular formation; Tyrosine Phosphorylation; Up-Regulation; Work; Zebrafish; base; clinically relevant; design; fluid flow; human FRAP1 protein; improved; inhibitor/antagonist; injury and repair; insight; kidney cell; mTOR Inhibitor; mouse model; novel; polycystic kidney disease 1 protein; prevent; receptor; renal ischemia; repaired; response

Autosomal-dominant (ADPKD) is the most common life-threatening genetic disease. We have recently found that polycystin-1 (PC1), the protein affected in ADPKD, functions in the regulation of STAT6 activity by ciliary mechanotransduction in renal epithelial cells. PC1 undergoes flow-dependent proteolytic cleavage which releases its cytoplasmic tail from the membrane, followed by nuclear translocation. The PC1 tail binds to STAT6 and the transcriptional co-activator P100, and stimulates STAT6-dependent gene expression. STAT6 translocates from primary cilia to nuclei upon cessation of fluid flow. The nuclear PC1 tail is highly expressed in cyst-lining epithelial cells in ADPKD. Expression of the PC1 tail stimulates proliferation in MDCK cells and results in renal cyst-formation in zebrafish embryos. Furthermore, MDCK cells respond to interleukin-4 (IL4) and IL13 similar to immune cells in that they activate STAT6, and up-regulate the expression if IL4/13 receptor chains. These results strongly suggest that PC1 functions to silence STAT6 activity in the normal healthy kidney. Cessation of lumenal fluid flow, e.g. due to renal injury, triggers PC1 cleavage, STAT6 activation and a proliferative response. We hypothesize that lack of functional PC1 in ADPKD leads to constitutive STAT6 activity and an aberrant proliferative "repair" response leading to cyst growth. Our preliminary results show that a clinically approved drug, known to inhibit STAT6, strongly inhibits renal growth and preserves renal function in a polycystic mouse model. We now propose to study in detail the mechanism of the regulation of STAT6 activity by PC1 and to test our hypotheses regarding the role of this novel signaling pathway in renal injury repair and ADPKD. In Aim 1, we will characterize the regulation of STAT6 in MDCK cells expressing a STAT6-responsive GFP reporter. The effects of the state of differentiation, PC1 tail expression, apical fluid flow and IL4/13 will be investigated. We will test whether STAT6 is activated in a scratch-wounding model. We will investigate the expression and localization/secretion of IL4/13 and IL4/13 receptor chains in response to STAT6 activation. Analysis of ADPKD tissue and polycystic mouse models will reveal whether IL4/13 receptors are up-regulated in cysts and whether they secrete IL4/13 into the lumen. Finally, we will test our hypothesis that the IL4/13/STAT6/PC1 pathway is activated in a mouse model of renal ischemia/reperfusion injury. In Aim 2, we will test whether crossing of STAT6 null mice with polycystic mouse models will result in suppression of renal cystic disease. Furthermore, we will investigate the amelioration of renal cystic disease by treatment with the STAT6 inhibitor and delineate the mechanism of action. In Aim 3, we will generate a transgenic mouse line over-expressing the soluble PC1 tail in a kidney-specific and doxycycline-inducible manner. Based on our results in MDCK cells and zebrafish, we anticipate that these animals will develop renal cystic disease and will mimic human ADPKD most closely mechanistically.

常染色体显性遗传（ADPKD）是最常见的危及生命的遗传病。我们最近发现多囊蛋白-1 (PC1)（ADPKD 中受影响的蛋白质）通过肾上皮细胞中的纤毛机械转导来调节 STAT6 活性。 PC1 经历流依赖性蛋白水解裂解，从膜上释放其细胞质尾部，然后进行核转位。 PC1 尾部与 STAT6 和转录共激活因子 P100 结合，并刺激 STAT6 依赖性基因表达。当液体流动停止时，STAT6 从初级纤毛转移到细胞核。核 PC1 尾部在 ADPKD 的囊肿衬里上皮细胞中高度表达。 PC1 尾部的表达刺激 MDCK 细胞增殖并导致斑马鱼胚胎中肾囊肿的形成。此外，MDCK 细胞对白细胞介素 4 (IL4) 和 IL13 的反应与免疫细胞类似，它们激活 STAT6，并上调 IL4/13 受体链的表达。这些结果强烈表明 PC1 具有沉默正常健康肾脏中 STAT6 活性的功能。腔内液体流动停止，例如由于肾损伤，触发 PC1 裂解、STAT6 激活和增殖反应。我们假设 ADPKD 中功能性 PC1 的缺乏会导致 STAT6 的组成型活性和异常的增殖“修复”反应，从而导致囊肿生长。我们的初步结果表明，一种已知可抑制 STAT6 的临床批准药物可强烈抑制多囊小鼠模型中的肾脏生长并保留肾功能。我们现在建议详细研究 PC1 调节 STAT6 活性的机制，并检验我们关于这种新型信号通路在肾损伤修复和 ADPKD 中的作用的假设。在目标 1 中，我们将表征表达 STAT6 响应 GFP 报告基因的 MDCK 细胞中 STAT6 的调节。将研究分化状态、PC1 尾部表达、顶端液流和 IL4/13 的影响。我们将测试 STAT6 是否在划伤模型中被激活。我们将研究 IL4/13 和 IL4/13 受体链响应 STAT6 激活的表达和定位/分泌。对 ADPKD 组织和多囊小鼠模型的分析将揭示囊肿中 IL4/13 受体是否上调以及它们是否将 IL4/13 分泌到管腔中。最后，我们将检验我们的假设，即 IL4/13/STAT6/PC1 通路在肾缺血/再灌注损伤的小鼠模型中被激活。在目标 2 中，我们将测试 STAT6 缺失小鼠与多囊小鼠模型的杂交是否会抑制肾囊性疾病。此外，我们将研究 STAT6 抑制剂治疗对肾囊性疾病的改善作用，并阐明其作用机制。在目标 3 中，我们将生成一种转基因小鼠系，以肾脏特异性和多西环素诱导的方式过度表达可溶性 PC1 尾部。根据我们对 MDCK 细胞和斑马鱼的研究结果，我们预计这些动物将患上肾囊性疾病，并且在机制上最接近人类 ADPKD。