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.

抽象的 开发新颖而强大的再生疗法的先决条件是揭示机制 控制茎/祖细胞的增殖和分化。干细胞能够增殖 无限期（自我更新），并区分为一种或多个细胞类型（多能性）。祖先是 具有多功能性但不能无限期分裂的干细胞的早期后代。茎/祖细胞 对于稳态组织维护和维修至关重要。但是，身份，起源和在肾脏中的作用 肾脏茎/祖细胞的再生仍然有争议。体内谱系跟踪是一个强大的 在本地情况下发现茎/祖细胞的技术。使用此技术，一些鼠标肾脏 已经鉴定出茎/祖细胞标记物，包括六，LGR5和PAX8。茎/祖细胞 表达这些标记物分化为各种细胞类型，但没有分化为收集导管细胞。因此， 收集管道的茎/祖细胞仍然神秘，因为特定的谱系追踪标记仍然是 无法使用。收集管系统是肾脏的最后一部分，以影响人体的电解质，酸 - 基础和流体平衡。它具有结构和功能上不同的主要细胞（PC），``插入细胞''（�- IC）和插入细胞（-IC）。体外研究表明-IC是假定的干细胞，并引起 - IC和PC，而PC被终极区分。但是，PI最近通过收集道路的体内研究 - 特定的组蛋白H3 K79甲基转移酶Dot1l敲除小鼠（DOT1LAC）推翻了这种传统观点。 没有dot1l函数，表达AQP2（一种已建立的PC标记）的细胞会引起`` - - 和ic iC均产生。 在此提案中，PI提议扩展和巩固了这些新发现。特别是，PI打算 从表达AQP2的细胞中发现IC的推导自然发生（即，无需dot1l删除）。这 将导致鉴定AQP2是收集管道细胞的遗体祖细胞标记（AIM 1）。 pi 还打算将DOT1L定义为收集管道分化的重要新型表观遗传调节剂（AIM 2）。 最后，PI提出的建议是发现DOT1L如何扮演其调节作用的建议。在这方面，他将发掘HDAC2 作为DOT1L的新合作伙伴和负调节器。 DOT1L和HDAC2互抑制其选项的功能 通过限制与DNA的关联。 PI将直接检验HDAC2删除是否拯救的假设 DOT1LAC表型（AIM 3）。所有必需的关键试剂，包括多个已发表和未发行 双重转基因小鼠模型已在PI的实验室中为该项目专门开发。 细胞，分子，遗传，肾脏生理学，电论，病理学和电显微镜检查 将使用方法。该提议确实具有很高的意义，影响和新颖性，因为如果成功， 将建立AQP2作为针对肾脏收集管道的新型祖细胞标记，DOT1L作为第一个 PC和IC差异化的表观遗传参与者，HDAC2是DOT1L的新型合作伙伴和调节器。