Mechanisms of Intestinal Stem Cell Injury and Repair

肠干细胞损伤与修复机制

• 批准号: 10197914
• 负责人: LINDA C. SAMUELSON
• 金额: $ 42.21万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-17 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10197914
• 关键词: Acute; Adult; Affect; Antibodies; Cell Count; Cell Maintenance; Cell physiology; Cells; Columnar Cell; Enterobacteria phage P1 Cre recombinase; Epithelial; Epithelial Cells; Exhibits; Generations; Genetic; Genetic Models; Hematopoietic Stem Cell Mobilization; Homeostasis; IGF1 gene; Injury; Insulin-Like Growth Factor I; Intestinal Diseases; Intestinal Mucosa; Intestines; Knowledge; Ligands; Longevity; Mesenchymal; Mesenchyme; Modeling; Mouse Strains; Mucous Membrane; Mus; Natural regeneration; Notch Signaling Pathway; Paneth Cells; Pathway interactions; Pharmacology; Radiation Injuries; Recovery; Regenerative response; Reserve Stem Cell; Role; Signal Pathway; Signal Transduction; Spottings; Testing; Therapeutic; Time; Tissues; adult stem cell; base; cell injury; crypt cell; design; gamma irradiation; injury and repair; injury recovery; intestinal crypt; intestinal epithelium; mouse genetics; mouse model; notch protein; novel; regenerative approach; regenerative therapy; regenerative tissue; repaired; stem cell expansion; stem cell function; stem cell model; stem cell niche; stem cell population; stem cells; theories; tissue repair; tool; treatment strategy

PROJECT SUMMARY This new R01 application seeks to define mechanisms of intestinal mucosal repair after stem cell injury, investigating the role of two key signaling pathways Dll1/4-Notch signaling and IGF1-mTORC1 signaling for promoting crypt repair. Adult stem cells fuel the continuous renewal of the intestinal epithelium. Prevailing theory suggests that there are two stem cell populations: active stem cells (also termed crypt base columnar (CBC) cells) important for epithelial cell maintenance during homeostasis and facultative stem cells (also termed quiescent or reserve stem cells) important for replenishing CBCs during crypt recovery after injury- induced stem cell loss. Intestinal crypts exhibit remarkable plasticity, with various epithelial cells in the crypt capable of reprogramming to fill unoccupied niche spots to replenish the CBC stem cell pool. Mechanisms of crypt repair and facultative stem cell mobilization are currently poorly understood. This project aims to define key niche signals that drive the regenerative response. Two mouse models of stem cell injury will be studied, including the well-established 12 Gy gamma-irradiation model and a new model of CBC loss resulting from acute Notch inhibition that we define in this proposal. Our preliminary findings show that these two injuries both result in rapid CBC loss followed by a hyperproliferative regenerative response associated with a surge of Notch pathway signaling. Our preliminary studies also show that IGF-1 expression is induced by injury and that mTORC1 signaling is required for crypt repair. The proposed studies will: (1) identify specific Notch ligands required for the regenerative response, (2) test the role of Paneth cells in the regeneration response, and (3) test the role of IGF-1 and mTORC1 signaling for crypt repair and facultative stem cell mobilization. Furthermore, the studies will expand our knowledge of the intestinal stem cell niche, including definition of key niche cells in the epithelium and mesenchyme that respond to injury to regulate stem cell function. The studies take advantage of available genetic mouse models and pharmacologic tools to manipulate the signaling pathways under study to probe their function in adult mice. Understanding mechanisms regulating intestinal stem cell expansion and crypt regeneration is important to identify key strategies to propagate adult stem cells in culture for regenerative therapies as well as to develop treatment strategies for intestinal diseases associated with mucosal injury.

项目总结 这一新的R01应用寻求确定干细胞损伤后肠粘膜修复的机制， 研究两个关键信号通路DLL1/4-Notch信号和IGF1-mTORC1信号在 促进地穴修复。成体干细胞为肠道上皮的持续更新提供动力。盛行 理论认为有两种干细胞群体：活跃的干细胞(也称为隐窝基柱状细胞 (CBC细胞)在动态平衡和兼性干细胞期间对上皮细胞的维持很重要 称为静止或储备干细胞)在损伤后的隐窝恢复过程中对补充CBCs很重要- 诱导干细胞丢失。肠隐窝显示出显著的可塑性，隐窝内有各种上皮细胞。 能够重新编程以填补空闲的利基位置，以补充CBC干细胞库。机制： 隐窝修复和兼性干细胞动员目前知之甚少。该项目旨在定义 驱动再生反应的关键利基信号。我们将研究两种干细胞损伤的小鼠模型， 包括公认的12Gy伽马辐照模型和一个新的CBC损失模型 我们在本提案中定义的急性切迹抑制。我们的初步调查结果显示，这两处损伤 导致CBC迅速丢失，随后出现与激增相关的过度增殖再生反应 缺口通路信号。我们的初步研究还表明，IGF-1的表达是由损伤诱导的，并且 加密修复需要mTORC1信令。拟议的研究将：(1)确定特定的Notch配体 再生反应所需的，(2)测试潘氏细胞在再生反应中的作用，以及(3) 测试IGF-1和mTORC1信号在隐窝修复和兼性干细胞动员中的作用。 此外，这些研究将扩大我们对肠道干细胞生态位的了解，包括关键 上皮和间充质中对损伤做出反应以调节干细胞功能的壁龛细胞。这些研究 利用现有的遗传小鼠模型和药理学工具来操纵信号转导 正在研究的途径，以探索其在成年小鼠中的功能。了解肠道调节机制 干细胞扩增和隐窝再生对于确定繁殖成体干细胞的关键策略很重要。 用于再生疗法的培养以及开发肠道疾病的治疗策略 与粘膜损伤有关。