Epigenetic Control of Kidney Fibrosis

肾脏纤维化的表观遗传控制

• 批准号: 8759361
• 负责人: WENZHENG ZHANG
• 金额: $ 22.68万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8759361
• 关键词: Ablation; Adverse effects; Age; Albuminuria; Aldosterone; Atrasentan; Biological Models; Biopsy; Blood; Cardiac; Cells; Cessation of life; Chronic Kidney Failure; Cicatrix; Clinical Research; DNA; Data; Development; Diabetes Mellitus; Diabetic Nephropathy; Diagnostic; Disease; Disease Progression; Duct (organ) structure; Edema; End stage renal failure; Endothelin-1; Epigenetic Process; Fibrosis; Foundations; Gene Targeting; Genes; Genetic; Genetic Markers; Genetic Screening; Genetic screening method; Glomerular Filtration Rate; Goals; HK2 gene; Histone H3; Human; Hypertension; Hypotension; Infusion procedures; Injury; Kidney; Kidney Failure; Knock-out; Knockout Mice; Link; Malignant Neoplasms; Mediating; Methyltransferase; Modeling; Molecular; Mus; Mutation; Patients; Pharmaceutical Preparations; Physiological; Play; Polycystic Kidney Diseases; Pre-Clinical Model; Predisposition; Public Health; Publishing; Renal function; Renin-Angiotensin-Aldosterone System; Repression; Role; Site; Somatic Mutation; Spironolactone; Streptozocin; Technology; Testing; Tubular formation; Up-Regulation; Vasoconstrictor Agents; Work; autocrine; cost; effective therapy; functional loss; genetic manipulation; high risk; hyperkalemia; improved; in vivo; inhibitor/antagonist; laser capture microdissection; mouse model; new therapeutic target; next generation sequencing; novel; paracrine; preconditioning; public health relevance

DESCRIPTION (provided by applicant): Kidney fibrosis is the hallmark of chronic kidney disease (CKD). Despite aggressive management, CKD often progresses to end-stage renal disease, which costs the US >$40 billion dollars and >90,000 deaths annually. The current main therapy targeting the renin-angiotensin-aldosterone (aldo) system with drugs including Spironolactone often delays, but does not stop the progression. This is also true for all other drugs such as endothelin 1 (ET1) blocker Atrasentan. The ineffectiveness and side effects including hyperkalemia and edema necessitate identification of novel therapeutic targets for the development of more effective treatments. Factors modulating the aldo global effect from its primary action site connecting tubule/collecting duct (CNT/CD) may prove better targets. However, such genetic and epigenetic factors remain virtually unknown, partially because of the intrinsic limitations of the clinical studies. These limitations include lack of kidney biopsies to verify the status of the disease, impossibility of genetic manipulation in patients to establish th causative relationship, and impracticability through mutational analyses with blood DNA to identify somatic mutations, which occur at atypical high rate in human kidney. Our published and preliminary data suggest that 1) Patients with diabetic nephropathy (DN) and CKD may have mutations in histone H3 K79 methyltransferase hDOT1L and abolished H3 dimethylation (H3m2K79) in their kidney biopsies; 2) Dot1a (encoded by Dot1l) represses ET1 and other aldo target genes. Aldo relieves Dot1a-mediated repression by multiple mechanisms; 3) CNT/CD-specific ablation of Dot1l in Dot1lAC mice causes abolition of H3m2K79, upregulation of ET1, and development of severe kidney fibrosis throughout the whole kidney. Accordingly, in this proposal, we will develop genetic markers to overcome the above limitations. To this end, we will use kidney biopsies from patients with DN and CKD, our mouse models bearing intact or disrupted Dot1l and ET1 in the CNT/CD, and their CNT/CD primary cells in combination of cutting-edge technologies including laser capture microdissection, next generation sequencing, and in vivo lineage tracing. Our specific aims are to study if DN and CKD patients have genetic defects in hDOT1L (Aim 1), study if Dot1l deletion accelerates kidney fibrosis in part by upregulating ET1 in mice (Aim 2), and study if Dot1a and ET1 modulate the global effect of aldo profibrotic action (Aim 3). Our studies may identify DOT1L as a novel repressor of ET1 and thus a new renoprotective factor, confirm loss of DOT1L function and thus H3m2K79 as an epigenetic driver of CKD, define Spironolactone + Atrasentan as a new effective combinational therapy of CKD, and lay the foundation of new genetic tests. If Dot1l and ET1 are genetically linked to CKD in humans, they may be exploited to develop genetic screening tests to identify patients at high risk of CKD and to determine their responsiveness to various aldo and ET1 inhibitors. Like ET1, DOT1L can also be considered as a potential new therapeutic target of CKD.

描述（由申请人提供）：肾脏纤维化是慢性肾脏病（CKD）的标志。尽管进行了积极的治疗，CKD 仍常常发展为终末期肾病，每年造成美国超过 400 亿美元的损失，并导致超过 90,000 人死亡。目前针对肾素-血管紧张素-醛固酮 (aldo) 系统的主要治疗方法是使用螺内酯等药物，通常会延迟但不能阻止病情进展。对于所有其他药物（例如内皮素 1 (ET1) 阻滞剂阿曲生坦）也是如此。无效和副作用（包括高钾血症和水肿）需要确定新的治疗靶点，以开发更有效的治疗方法。从连接小管/集合管 (CNT/CD) 的主要作用位点调节 ALDO 整体效应的因素可能会成为更好的目标。然而，此类遗传和表观遗传因素实际上仍然未知，部分原因是临床研究的内在局限性。这些限制包括缺乏肾活检 验证疾病的状态，不可能对患者进行基因操作以确定因果关系，并且通过血液 DNA 突变分析来识别体细胞突变是不切实际的，体细胞突变在人类肾脏中发生率不典型高。我们发表的初步数据表明：1) 糖尿病肾病 (DN) 和 CKD 患者的肾活检中可能存在组蛋白 H3 K79 甲基转移酶 hDOT1L 突变，并消除了 H3 二甲基化 (H3m2K79)； 2) Dot1a（由Dot1l编码）抑制ET1和其他aldo靶基因。 Aldo 通过多种机制缓解 Dot1a 介导的抑制； 3) Dot1lAC小鼠中Dot1l的CNT/CD特异性消融导致H3m2K79的消除、ET1的上调以及整个肾脏中严重肾纤维化的发展。因此，在本提案中，我们将开发遗传标记来克服上述限制。为此，我们将使用来自 DN 和 CKD 患者的肾活检、我们的 CNT/CD 中带有完整或破坏的 Dot1l 和 ET1 的小鼠模型，以及它们的 CNT/CD 原代细胞，并结合包括激光捕获显微切割在内的尖端技术、下一代测序和体内谱系追踪。我们的具体目标是研究 DN 和 CKD 患者的 hDOT1L 是否存在遗传缺陷（目标 1），研究 Dot1l 缺失是否通过上调小鼠的 ET1 部分加速肾纤维化（目标 2），以及研究 Dot1a 和 ET1 是否调节整体效应醛促纤维化作用（目标 3）。我们的研究可能将 DOT1L 确定为 ET1 的新型抑制因子，从而确定新的肾脏保护因子，确认 DOT1L 功能丧失，从而确认 H3m2K79 作为 CKD 的表观遗传驱动因素，将螺内酯 + 阿曲生坦定义为 CKD 的新有效联合疗法，并奠定基础新的基因测试。如果 Dot1l 和 ET1 与人类 CKD 存在遗传关联，则可以利用它们来开发基因筛查测试，以识别 CKD 高风险患者，并确定他们对各种 aldo 和 ET1 抑制剂的反应。与ET1一样，DOT1L也可以被认为是CKD的潜在新治疗靶点。