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: 10475689
• 负责人: ROBERT O HEUCKEROTH
• 金额: $ 58.61万
• 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/10475689
• 关键词: 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; abdominal distension; antimicrobial peptide; beneficial microorganism; design; fecal transplantation; feeding; gut inflammation; 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.

项目概述：我们的目标是改善先天性巨结肠(HSCR)儿童的生活，这是一种- 肠道末端缺乏肠道神经系统(ENS)的先天出生缺陷。因为 ENS调节肠道功能的大部分方面，缺乏ENS的“无神经节”的肠道不能很好地工作。 症状包括顽固性便秘、胆汁性呕吐、腹胀、生长衰竭和HSCR- 结肠炎(HAEC)。HAEC是最危险的问题，因为除了肠道 炎症，在HAEC期间，细菌可能会穿过肠上皮细胞，导致败血症，这可能是致命的。 HSCR的主要治疗方法是通过手术切除无神经节段肠并重新附着含ENS的肠管 从肠子到肛门边缘。不幸的是，约35%的儿童在渡过难关后仍有问题 手术，包括HAEC。一个长期存在的谜团是，为什么 患有HSCR的儿童。特别是，有些孩子从来没有患过HAEC，但另一些孩子重复过HAEC 手术前和手术后的情况。无神经节细胞增多症的长度、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 而在HSCR或HSCR模型中，几乎没有对肠道内的小分子进行研究。使用Piebald 致死的sl/sl小鼠，一个公认的hscr模型，我们发现两者之间的存活率相差5倍。 鼠标设施。存活率的差异与无神经节细胞肠管的长度、不同的基因或 死因，而且我们不做手术。相反，存活率的差异反映了 可以被环境中的非遗传因素改变的HSCR病理生理学。我们假设 5倍的存活率差异是因为sl/sl小鼠被喂食不同类型的食物和有不同的肠道。 每个机构都有微生物。饮食和肠道微生物的差异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，通过多种方式影响肠道屏障功能 会影响败血症风险。Aim 1验证了这样一种假设，即饮食和微生物通过交换饲喂给 在每个机构的SL/SL，制造无菌小鼠，并使用粪便将粪便移植到无菌小鼠 从每一家机构。新的初步数据表明，仅仅改变饮食就能显著改变sl/sl患者的存活率。 老鼠。目标2使用解剖和功能定义了不同机构的肠屏障在sl/sl上的差异。 接近并鉴定穿过肠道上皮导致败血症的微生物。目标3定义了粘膜- 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，我们将知道是否可以操纵饮食或肠道微生物来提高HSCR的存活率 模型，并将有明确的机制，以改变脓毒症风险。然后可以利用这些数据来设计 人类临床试验，以改善HSCR儿童的预后，减少HAEC的发生。