Epigenetic Control of Kidney Fibrosis

肾脏纤维化的表观遗传控制

• 批准号: 9186403
• 负责人: WENZHENG ZHANG
• 金额: $ 23.7万
• 依托单位: ALBANY MEDICAL COLLEGE
• 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/9186403
• 关键词: Epigenetic; Control; Kidney; Fibrosis

Abstract A prerequisite to the development of novel and powerful regenerative therapeutics is to reveal the mechanisms controlling the proliferation and differentiation of stem/progenitor cells. Stem cells are capable of proliferating indefinitely (self-renewal) and differentiating into one or multiple cell types (pluripotentiality). Progenitors are early descendants of stem cells that have pluripotentiality, but cannot divide indefinitely. Stem/progenitor cells are critical for homeostatic tissue maintenance and repair. However, the identity, origin, and role in renal regeneration of kidney stem/progenitor cells remain controversial. In vivo lineage tracing is a powerful technique to discover stem/progenitor cells in their native context. With this technique, a few mouse kidney stem/progenitor cell markers have been identified, including Six2, Lgr5, and Pax8. The stem/progenitor cells expressing these markers differentiate into various cell types, but not the collecting duct cells. Therefore, the stem/progenitor cells of the collecting duct remain mysterious, because a specific lineage-tracing marker is still not available. The collecting duct system is the final part of the kidney to influence the body's electrolyte, acid- base, and fluid balance. It has structurally and functionally distinct principal cells (PC), �-intercalated cells (�- IC), and �-intercalated cells (�-IC). In vitro studies suggest that �-IC are putative stem cells and give rise to �- IC and PC, while PC are terminally differentiated. However, the PI's recent in vivo studies with collecting-duct- specific histone H3 K79 methyltransferase Dot1l knockout mice (Dot1lAC) overturned this traditional view. Without Dot1l function, the cells expressing Aqp2, a well established PC marker, give rise to both �-, and �-IC. In this proposal, the PI proposes to extend and solidify these novel findings. In particular, the PI intends to discover derivation of IC from Aqp2-expressing cells occurs naturally (i.e, without need of Dot1l deletion). This would lead to identification of Aqp2 as the missing progenitor marker of collecting duct cells (Aim 1). The PI also intends to define Dot1l as a critical novel epigenetic regulator of collecting duct differentiation (Aim 2). Finally, the PI proposes to discover how Dot1l plays its regulatory role. In this regard, he will unearth HDAC2 as a new partner and negative regulator of Dot1l. Dot1l and HDAC2 mutually inhibit their opponent's function by restricting association with DNA. The PI will directly test the hypothesis whether HDAC2 deletion rescues the Dot1lAC phenotype (Aim 3). All of the required key reagents including multiple published and unpublished double and triple transgenic mouse models have been exclusively developed in the PI's lab for this project. Cellular, molecular, genetic, reno-physiological, electro-physiological, pathological, and electron microscopic approaches will be used. This proposal truly has high significance, impact and novelty because if successful, it will establish Aqp2 as a novel progenitor cell marker specific for renal collecting duct, Dot1l as the first epigenetic player in PC and IC differentiation, and HDAC2 as a novel partner and regulator of Dot1l.

摘要 开发新的和强大的再生疗法的先决条件是揭示其机制 控制干/祖细胞的增殖和分化。干细胞能够增殖 无限期地（自我更新）和分化成一种或多种细胞类型（多能性）。祖细胞 干细胞的早期后代具有多能性，但不能无限分裂。干/祖细胞 对维持和修复体内平衡至关重要然而，肾脏疾病的身份，起源和作用 肾干/祖细胞的再生仍然存在争议。体内谱系追踪是一种强大的 技术来发现干/祖细胞在其天然环境中。通过这项技术，一些老鼠的肾脏 干/祖细胞标志物已被鉴定，包括Six 2、Lgr 5和Pax 8。该干细胞/祖细胞 表达这些标记的细胞分化成各种细胞类型，但不分化成集合管细胞。因此 集合管的干/祖细胞仍然是神秘的，因为一个特定的谱系追踪标记仍然是未知的。 不可用.集合管系统是肾脏的最后一部分，影响身体的电解质，酸- 基础和体液平衡它具有结构和功能不同的主细胞（PC），β-闰细胞（β-intercalated cell，PC）， IC）和β-intercalated cells（β-IC）。体外研究表明，β-IC是假定的干细胞，并产生β-IC。 IC和PC，而PC是有终端区别的。然而，PI最近的体内研究与收集管- 特异性组蛋白H3 K79甲基转移酶Dot 11基因敲除小鼠（Dot 11AC）的出现推翻了这一传统观点。 如果没有Dot 1 l功能，表达Aqp 2（一种公认的PC标记物）的细胞会产生β-和β-IC。 在本提案中，PI建议扩展和巩固这些新发现。特别是，PI打算 发现IC从表达Aqp 2的细胞中的衍生是天然发生的（即，不需要Dot 11缺失）。这 将导致鉴定Aqp 2为集合管细胞的缺失祖细胞标志物（Aim 1）。的PI 还打算将Dot 1 l定义为集合管分化的关键的新型表观遗传调节因子（Aim 2）。 最后，PI建议发现Dot 1 l如何发挥其调节作用。在这方面，他将挖掘HDAC 2 作为Dot 1 l的新伙伴和负调节器。Dot 11和HDAC 2相互抑制其对手的功能 通过限制与DNA的结合PI将直接检验HDAC 2缺失是否可挽救 Dot 11AC表型（Aim 3）。所有必需的关键试剂，包括多个已发表和未发表的试剂 PI的实验室专门为该项目开发了双转基因和三转基因小鼠模型。 细胞、分子、遗传、肾生理、电生理、病理和电子显微镜 将使用的方法。这项建议确实具有很高的意义、影响和新奇，因为如果成功， 将建立Aqp 2作为肾集合管特异性的新的祖细胞标志物，Dot 1 l作为第一个 PC和IC分化中的表观遗传参与者，以及HDAC 2作为Dot 1 l的新伴侣和调节剂。