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Mechanisms of tuft cell mediated regulation of the intestinal stem cell niche following injury

损伤后簇细胞介导的肠道干细胞生态位调节机制

基本信息

批准号：
10401832
负责人：
Courtney Wayne Houchen
金额：
$ 32.63万
依托单位：
UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-20 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10401832
关键词：
Abdominal Pain Animals Apoptosis Apoptotic Binding Biological Assay Blood Circulation Cell Cycle Cell Survival Cells Cessation of life DNA Damage Data Development Diarrhea Dinoprostone Diphtheria Toxin Dose Epithelial Epithelial Cells Functional disorder Health Hemorrhage Impairment In Vitro Inflammatory Injury Intestinal permeability Intestines LGR5 gene Measures Mediating Mediator of activation protein Molecular Mus Natural regeneration Parasitic infection Patients Phosphotransferases Play Process Radiation Radiation Dose Unit Radiation Enteritis Radiation Injuries Radiation Protection Radiation therapy Regulation Reporter Reporting Reserve Stem Cell Resistance Role Source Testing Tight Junctions Villus Whole-Body Irradiation ataxia telangiectasia mutated protein base cancer therapy clinically relevant epithelial stem cell genomic signature genotoxicity gut bacteria injury and repair intestinal crypt intestinal epithelium intraepithelial overexpression paracrine premature radiation adverse effect radiation response radioresistant reconstitution rectal regenerative response response to injury severe injury single cell analysis stem cell niche stem cell survival stem cells transcriptome sequencing

项目摘要

One of the major and devastating adverse effects of radiation therapy is the development of radiation enteritis (RE). The number of patients receiving radiation therapy in the USA, as a component of their primary cancer treatment, is forecast to increase by more than 20% over the next decade to almost 600,000 per year. RE is an intestinal inflammatory process that occurs in response to radiotherapy. It is a major health concern characterized by abdominal pain, diarrhea, and rectal bleeding. It can be complicated by translocation of gut bacteria into the circulation due to the loss of intestinal epithelial cells, disruption of intraepithelial tight junctions, and loss of regenerative ability resulting in impairment of gut function and even death. Relatively little is known about the mechanisms underlying the intestinal epithelial injury repair, stem cell survival and crypt regeneration in RE. Doublecortin like kinase 1 (Dclk1) marks intestinal tuft cells and deletion of Dclk1 within intestinal epithelial cells resulted in premature death of mice following severe radiation injury, suggesting that Dclk1 is a major mediator of the crypt epithelial response to genotoxic injury. We reported that Dclk1 interacts with ataxia- telangiectasia mutated (ATM) and phosphorylates ATM activating the DNA damage response (DDR) following radiation injury . Furthermore, intestinal epithelial cells overexpressing Dclk1 are more resistant to radiation than the control cells. These data suggest that Dclk1+ tuft cell plays a critical role in epithelial cell survival following severe genotoxic injury. Recently, single cell analysis in the intestine has revealed that Dclk1+ epithelial tuft cell is the primary source of Cox1 (Ptgs1) and Cox2 (Ptgs2). Based on our previous studies, Cox1 and Cox2 are the major source of PGE2 in the intestine, that protects the gut after severe radiation injury. However, the molecular mechanism that regulates the survival of intestinal tuft cells following severe injury is unclear and the role of intestinal crypt tuft cells in epithelial stem cell survival is completely unknown. Our central hypothesis is that intestinal crypt tuft cell survival following severe genotoxic injury is mediated by Dclk1-dependent regulation of the ATM/ATR DNA damage response; further these crypt tuft cells coordinate the survival of neighboring epithelial stem cells via a PGE2-dependent mechanism. We will test our hypothesis with the following specific aims: Aim 1: To elucidate the molecular mechanism by which tuft cells survive lethal dose radiation injury. Aim 2: To determine the mechanisms by which tuft cells coordinate the survival of crypt intestinal stem cells (ISCs). Aim 3: To determine the role of tuft cell specific PGE2 on intestinal crypt regeneration and epithelial restitution following severe radiation injury. The proposed study will (1) determine the mechanisms by which surviving intestinal epithelial Dclk1+ tuft following severe genotoxic injury coordinately regulate the crypt stem cell survival via a paracrine mediated mechanism and (2) eventually answer the clinically-relevant question of how RE contribute to gut dysfunction and understand the importance of epithelial tuft cells in augmenting crypt survival, after severe genotoxic injury.

放射治疗的主要和破坏性副作用之一是放射性肠炎的发生（关于）。在美国接受放射治疗（作为原发癌症的一部分）的患者人数预计未来十年将增加 20% 以上，达到每年近 600,000 人。稀土是一个因放疗而发生的肠道炎症过程。这是一个主要的健康问题其特征是腹痛、腹泻和直肠出血。肠道移位可能会使情况变得复杂由于肠上皮细胞的损失、上皮内紧密连接的破坏，细菌进入循环系统，再生能力的丧失导致肠道功能受损甚至死亡。知之甚少关于肠上皮损伤修复、干细胞存活和隐窝再生的机制在RE。双皮质素样激酶 1 (Dclk1) 标记肠道簇细胞和肠道内 Dclk1 的缺失上皮细胞导致严重辐射损伤后小鼠过早死亡，表明 Dclk1 是一种隐窝上皮对基因毒性损伤反应的主要介质。我们报道了 Dclk1 与共济失调相互作用毛细血管扩张突变 (ATM) 和磷酸化 ATM 激活 DNA 损伤反应 (DDR) 辐射损伤。此外，过度表达 Dclk1 的肠上皮细胞比肠道上皮细胞更能抵抗辐射。对照细胞。这些数据表明 Dclk1+ 簇绒细胞在上皮细胞存活后发挥着关键作用严重的遗传毒性损伤。最近，肠道单细胞分析表明 Dclk1+ 上皮簇细胞是 Cox1 (Ptgs1) 和 Cox2 (Ptgs2) 的主要来源。根据我们之前的研究，Cox1 和 Cox2 是肠道中 PGE2 的主要来源，可在严重辐射损伤后保护肠道。然而，分子严重损伤后调节肠道簇细胞存活的机制尚不清楚，并且其作用肠隐窝簇状细胞上皮干细胞的存活情况完全未知。我们的中心假设是严重基因毒性损伤后肠隐窝簇细胞的存活是由 Dclk1 依赖性介导的 ATM/ATR DNA 损伤反应的调节；此外，这些隐窝簇细胞协调生存邻近的上皮干细胞通过 PGE2 依赖的机制。我们将用以下方法检验我们的假设以下具体目标：目标 1：阐明簇细胞致命存活的分子机制剂量辐射损伤。目标 2：确定簇细胞协调存活的机制隐窝肠干细胞（ISC）。目标 3：确定簇细胞特异性 PGE2 对肠道的作用严重辐射损伤后的隐窝再生和上皮恢复。拟议的研究将 (1) 确定存活肠上皮 Dclk1+ 簇的机制严重的基因毒性损伤后通过旁分泌介导协调调节隐窝干细胞的存活机制和（2）最终回答 RE 如何导致肠道功能障碍的临床相关问题并了解严重基因毒性损伤后上皮簇细胞在增强隐窝存活方面的重要性。