Defining non-genetic mechanisms that prevent death in a Hirschsprung disease mouse model

定义预防先天性巨结肠症小鼠模型死亡的非遗传机制

• 批准号: 10277960
• 负责人: ROBERT O HEUCKEROTH
• 金额: $ 57.63万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-27 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10277960
• 关键词: Abdomen; Affect; Anatomy; Bacteria; Biological Assay; Cause of Death; Cell physiology; Cessation of life; Child; Clinical Trials; Colon; Complex; Congenital Abnormality; Congenital Megacolon; Constipation; Dangerousness; Data; Defect; Diet; Dietary Component; Disease; Distal; Enteric Nervous System; Enterocolitis; Environment; Epithelial; Epithelial Cells; Excision; Exclusive Breastfeeding; Failure; Feces; Food; Functional disorder; Genetic; Germ-Free; Goals; Growth; Human; In Vitro; Inbreeding; Inflammation; Institution; Intestines; Length; Life; Microbe; Modeling; Mucins; Mucous body substance; Mus; Nervous system structure; Nutrient; Operative Surgical Procedures; Outcome; Pediatric Hospitals; Philadelphia; Piebaldism; Positioning Attribute; Postoperative Period; Probiotics; Property; Proteins; Quebec; RNA; Recurrence; Risk; Sepsis; Severities; Symptoms; Testing; Time; Transition zone of anal mucous membrane; Transplantation; Universities; Vomiting; antimicrobial peptide; beneficial microorganism; design; fecal transplantation; feeding; gut microbes; human data; improved; improved outcome; in vivo; innovation; microbial; mouse model; mucosal microbiota; non-genetic; novel therapeutic intervention; premature; prevent; small molecule

Project Summary: Our goal is to improve the lives of children with Hirschsprung disease (HSCR), a life- threatening birth defect where the enteric nervous system (ENS) is absent from the end of the bowel. Because the ENS regulates most aspects of bowel function, “aganglionic” bowel that lacks ENS does not work well. Symptoms include intractable constipation, bilious vomiting, abdominal distension, growth failure and HSCR- associated enterocolitis (HAEC). HAEC is the most dangerous problem because in addition to bowel inflammation, during HAEC, bacteria may move across the bowel epithelium causing sepsis that can be fatal. Primary treatment for HSCR is pull-through surgery to remove aganglionic bowel and re-attach ENS-containing bowel to near the anal verge. Unfortunately, ~35% of children continue to have problems after pull-through surgery, including HAEC. One long-standing mystery is why symptom onset and severity differ so much among children with HSCR. In particular, some children never have HAEC, but other children have repeated HAEC episodes before and after pull-through surgery. Length of aganglionosis, genetic differences, and surgical details undoubtedly impact HAEC risk and HSCR outcomes. The impact of non-genetic factors like diet, gut microbes and small molecules inside the bowel have barely been investigated in HSCR or in HSCR models. Using Piebald lethal sl/sl mice, a well-established HSCR model, we discovered a 5-fold difference in survival between two mouse facilities. The survival difference is not related to the length of aganglionic bowel, distinct genetics, or cause of death, and we do not perform surgery. Instead, the survival difference reflects fundamental aspects of HSCR pathophysiology that can be altered by non-genetic factors in the environment. We hypothesized that the 5-fold survival difference occurs because sl/sl mice are fed different types of food and have different bowel microbes at each institution. Differences in diet and gut microbes can alter small molecules within the bowel. Many small molecules including nutrients in food and microbial metabolites impact bowel barrier function in ways that affect sepsis risk. Aim 1 tests the hypothesis that diet and microbes affect survival by swapping diets fed to sl/sl at each institution, making germ-free mice, and performing fecal transplant into germ-free mice using stool from each institution. New preliminary data suggest that simply changing diet markedly alters survival in sl/sl mice. Aim 2 defines how the bowel barrier differs in sl/sl between institutions using anatomic and functional approaches and identifies microbes that cross bowel epithelium to cause sepsis. Aim 3 defines mucosa- associated microbes and small molecules within the bowel lumen that could affect barrier function. At the completion of this study we will know if diet or gut microbes can be manipulated to improve survival in HSCR models and will have defined mechanisms that alter sepsis risk. These data can then be leveraged to design human clinical trials to improve outcomes in children with HSCR and reduce HAEC occurrence.

项目摘要：我们的目标是改善患有先天性巨结肠症 (HSCR) 的儿童的生活，这是一种致命的疾病 肠道末端缺乏肠神经系统 (ENS) 的威胁性出生缺陷。因为 ENS 调节肠道功能的大部分方面，缺乏 ENS 的“神经节”肠道无法正常工作。 症状包括顽固性便秘、胆汁性呕吐、腹胀、生长障碍和 HSCR- 相关小肠结肠炎（HAEC）。 HAEC 是最危险的问题，因为除了肠道 炎症期间，HAEC 期间，细菌可能会穿过肠上皮，导致致命的败血症。 HSCR 的主要治疗方法是拉穿手术，切除无神经节肠并重新连接含有 ENS 的肠管 肠管靠近肛门边缘。不幸的是，约 35% 的儿童在克服困难后仍然存在问题 手术，包括HAEC。一个长期存在的谜团是，为什么不同人群的症状出现和严重程度差异如此之大？ 患有 HSCR 的儿童。特别是，有些孩子从未患有HAEC，但其他孩子却重复出现HAEC 拉穿手术前后的发作。无神经节症的长度、遗传差异和手术细节 无疑会影响 HAEC 风险和 HSCR 结果。饮食、肠道微生物等非遗传因素的影响 肠道内的小分子几乎没有在 HSCR 或 HSCR 模型中进行过研究。使用花斑 致死性 sl/sl 小鼠，一种成熟的 HSCR 模型，我们发现两种小鼠的生存率存在 5 倍差异 鼠标设施。生存差异与无神经节肠的长度、不同的遗传学或 死亡原因，我们不进行手术。相反，生存差异反映了以下基本方面： HSCR 病理生理学可被环境中的非遗传​​因素改变。我们假设 由于 sl/sl 小鼠喂食不同类型的食物并且具有不同的肠道，因此出现 5 倍的生存差异 每个机构的微生物。饮食和肠道微生物的差异可能会改变肠道内的小分子。 许多小分子，包括食物中的营养素和微生物代谢物，都会以多种方式影响肠屏障功能 影响脓毒症风险。目标 1 通过交换饮食来检验饮食和微生物影响生存的假设 各机构sl/sl，制作无菌小鼠，并利用粪便将粪便移植到无菌小鼠体内 来自各个机构。新的初步数据表明，简单地改变饮食即可显着改变 sl/sl 的生存率 老鼠。目标 2 使用解剖学和功能学定义了不同机构之间肠屏障 sl/sl 的差异 接近并识别穿过肠上皮导致败血症的微生物。目标 3 定义粘膜- 肠腔内可能影响屏障功能的相关微生物和小分子。在 完成这项研究后，我们将知道是否可以通过控制饮食或肠道微生物来提高 HSCR 患者的生存率 模型并将具有改变脓毒症风险的明确机制。然后可以利用这些数据来设计 人体临床试验旨在改善 HSCR 儿童的预后并减少 HAEC 的发生。