Molecular pathogenesis of calcineurin inhibitor-induced hypertension

钙调神经磷酸酶抑制剂诱发高血压的分子发病机制

• 批准号: 8727539
• 负责人: David H Ellison
• 金额: $ 36.98万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-21 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8727539
• 关键词: Active Sites; Binding; Blood Pressure; Calcineurin; Calcineurin inhibitor; Calcium; Calmodulin; Cells; Chloride Ion; Chlorides; Chronic Kidney Failure; Clinical; Complex; Cyclosporine; Distal; Distal convoluted renal tubule structure; Electrolytes; Equilibrium; Excretory function; Exhibits; Exposure to; Functional disorder; Future; Genetic; Goals; Graft Survival; Hereditary Disease; Human; Hypertension; Immunophilins; Immunosuppression; Immunosuppressive Agents; In Vitro; Incidence; Kidney; Kidney Failure; Knock-out; Knockout Mice; Mediating; Medicine; Metabolic acidosis; Modeling; Molecular; Mus; Nature; Nephrons; Organ; Organ Transplantation; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphoric Monoester Hydrolases; Phosphotransferases; Potassium; Protein Serine/Threonine Phosphatase; Protein phosphatase; Proteins; Pseudohypoaldosteronism; Publishing; Regulation; Renal tubule structure; SLC12A3 gene; Shunt Device; Signal Pathway; Signaling Molecule; Sodium Chloride; Solid; Syndrome; System; Tacrolimus; Tacrolimus Binding Protein 1A; Testing; Therapeutic; Thiazide Diuretics; Toxic effect; Transplant Recipients; Tubular formation; drug development; hyperkalemia; improved; in vivo; inhibitor/antagonist; inorganic phosphate; novel; phosphatase inhibitor; pressure; protein phosphatase inhibitor-1; research study; urinary

DESCRIPTION (provided by applicant): This project will examine how calcineurin inhibitors, such as tacrolimus and cyclosporine, cause hypertension with potassium retention. In preliminary published studies, we showed that tacrolimus activates the thiazide-sensitive Na- Cl cotransporter (NCC) in the kidney. This effect was found to be essential for the resulting hypertension and potassium retention. Here we will examine the mechanisms involved. Calcineurin is a protein phosphatase and we will test whether it removes phosphates from NCC directly, to inhibit its actions, or whether the pathway involves calcineurin acting on intermediar proteins. We will determine whether other protein phosphatases, including protein phosphatases 1A, 2A, and 4 remove phosphates from NCC. Protein phosphatase inhibitor 1 (PPP1r1a) is a canonical target of calcineurin and is highly expressed along the distal nephron. In preliminary experiments by our collaborator, genetic deletion of this inhibitor was found to reduce the abundance of phosphorylated NCC in vivo. Therefore, we will test whether calcineurin regulates NCC activity via PPP1r1a. PPP1r1a is known to inhibit the actions of protein phosphatase 1A, which can act on the kinase SPAK. SPAK is the canonical NCC activating protein. Thus, we will test the over arching hypothesis that calcineurin inhibitors activate PPP1r1a in the distal nephron, leading to inhibition of PP1A, SPAK activation, and enhanced NCC activity. This model will be tested both in vitro, using a novel cell system that we developed recently, and in vivo, by knocking out key components of the signaling pathway. The proposal has substantial clinical implications, both in terms of patient treatment today, and in terms of drug development for tomorrow.

描述（由申请人提供）：该项目将研究钙调神经磷酸酶抑制剂（例如他克莫司和环孢素）如何引起高血压伴钾潴留。在初步发表的研究中，我们表明他克莫司可激活肾脏中噻嗪类敏感的 Na-Cl 协同转运蛋白 (NCC)。人们发现这种效应对于由此产生的高血压和钾潴留至关重要。在这里我们将研究所涉及的机制。钙调磷酸酶是一种蛋白磷酸酶，我们将测试它是否直接从 NCC 中去除磷酸盐以抑制其作用，或者该途径是否涉及钙调磷酸酶作用于中间蛋白。我们将确定其他蛋白磷酸酶（包括蛋白磷酸酶 1A、2A 和 4）是否可以去除 NCC 中的磷酸盐。蛋白磷酸酶抑制剂 1 (PPP1r1a) 是钙调神经磷酸酶的典型靶标，并沿远端肾单位高表达。在我们的合作者的初步实验中，发现该抑制剂的基因缺失会降低体内磷酸化 NCC 的丰度。因此，我们将测试钙调磷酸酶是否通过 PPP1r1a 调节 NCC 活性。已知 PPP1r1a 可以抑制蛋白磷酸酶 1A 的作用，而蛋白磷酸酶 1A 可以作用于激酶 SPAK。 SPAK 是典型的 NCC 激活蛋白。因此，我们将测试一个总体假设，即钙调神经磷酸酶抑制剂激活远端肾单位中的 PPP1r1a，从而抑制 PP1A、SPAK 激活并增强 NCC 活性。该模型将使用我们最近开发的新型细胞系统进行体外测试，并通过敲除信号通路的关键组件进行体内测试。该提案对于当今的患者治疗和未来的药物开发都具有重大的临床意义。