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

• 批准号: 9817059
• 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
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-20 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9817059
• 关键词: Abdominal Pain; Animals; Apoptosis; Apoptotic; Asses; 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; Stem cells; Testing; Tight Junctions; Villus; Whole-Body Irradiation; ataxia telangiectasia mutated protein; base; cancer therapy; clinically relevant; 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; single cell analysis; stem cell niche; transcriptome sequencing

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.

放射治疗的主要且毁灭性的不利影响之一是辐射肠炎的发展 （关于）。作为原发性癌症的一部分，在美国接受放射疗法的患者人数 预计在接下来的十年中，预计将增加20％以上，每年将近60万。 Re是一个 响应放射疗法而发生的肠道炎症过程。这是一个主要的健康问题 以腹痛，腹泻和直肠出血为特征。肠的易位可能会使它复杂化 细菌由于肠上皮细胞的丧失而进入循环系统，上皮内紧密连接的破坏， 再生能力的丧失，导致肠道功能损害甚至死亡。相对鲜为人知 关于肠上皮损伤修复，干细胞存活和隐窝再生的机制 在Re中。像激酶1（DCLK1）一样标记肠簇细胞和肠内DCLK1的缺失 上皮细胞导致严重辐射损伤后小鼠过早死亡，这表明DCLK1是一个 隐窝上皮反应对遗传毒性损伤的主要介体。我们报道DCLK1与共济失调相互作用 突变（ATM）并磷酸化ATM激活DNA损伤响应（DDR）之后， 辐射损伤。此外，过表达DCLK1的肠上皮细胞比辐射更具抵抗力 控制细胞。这些数据表明DCLK1+簇细胞在上皮细胞存活中起着至关重要的作用 严重的遗传毒性损伤。最近，肠道中的单细胞分析表明DCLK1+上皮簇细胞 是COX1（PTGS1）和COX2（PTGS2）的主要来源。根据我们以前的研究，COX1和COX2是 肠道中PGE2的主要来源，可在严重的辐射损伤后保护肠道。但是，分子 调节严重损伤后肠道细胞存活的机制尚不清楚，并且 上皮干细胞存活中的肠道隐窝细胞是完全未知的。我们的中心假设是 严重的遗传毒性损伤后肠道隐窝簇细胞的存活是由DCLK1依赖性介导的 调节ATM/ATR DNA损伤响应；此外，这些地穴簇细胞协调生存 通过PGE2依赖性机制的相邻上皮干细胞的形象。我们将通过 以下特定目的：目标1：阐明簇状细胞生存的分子机制 剂量辐射损伤。目的2：确定簇簇坐标的机制 地穴肠道干细胞（ISC）。 AIM 3：确定簇细胞特异性PGE2在肠道上的作用 严重辐射损伤后的隐窝再生和上皮恢复。 拟议的研究将（1）确定存活的肠上皮DCLK1+簇的机制 严重的遗传毒性损伤协调通过旁分泌介导的隐窝干细胞存活 机制和（2）最终回答了与肠道功能障碍有何贡献的临床相关问题 并了解严重的遗传毒性损伤后，上皮簇细胞在增强隐窝存活中的重要性。