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.

放射治疗的主要和毁灭性的副作用之一是放射性肠炎的发展