Valerobetaine is a microbe-generated metabolite that induces mitochondrial biogenesis and maintains epithelial integrity

缬甜菜碱是一种微生物产生的代谢物，可诱导线粒体生物发生并维持上皮完整性

• 批准号: 10680153
• 负责人: Lauren Casey Askew
• 金额: $ 5.27万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10680153
• 关键词: 3-Dimensional; Affect; Animals; Bioenergetics; Biogenesis; Biology; Biopsy; Carnitine; Cell Proliferation; Cells; Cellular Metabolic Process; Chronic; Colitis; Colon; Colonoscopes; Communication; Complex; Data; Development; Disease; Energy Metabolism; Epithelial Cells; Epithelium; Etiology; Event; Experimental Models; Family; Forcep; Foundations; Functional disorder; Gastroenterology; Gastrointestinal Diseases; Gastrointestinal tract structure; Gene Expression; Generations; Germ-Free; Gnotobiotic; Goals; Grant; Health; Hepatocyte; Homeostasis; Immune response; In Vitro; Indoles; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Injury; Intestines; Knowledge; Leaky Gut; Maintenance; Mass Spectrum Analysis; Mediating; Metabolism; Methodology; Methods; Microbe; Mitochondria; Modeling; Modification; Molecular; Morbidity - disease rate; Mus; Organoids; Persons; Phenotype; Physiology; Play; Proliferating; Quality of life; Research; Risk Factors; Role; Science; Scientist; Signal Pathway; Testing; Therapeutic; Tissues; Training; Volatile Fatty Acids; Work; Wound models; beneficial microorganism; body system; commensal bacteria; fatty acid oxidation; functional plasticity; gastrointestinal epithelium; gut health; gut homeostasis; gut inflammation; gut microbiome; gut microbiota; host microbiome; in vivo; interest; intestinal crypt; intestinal epithelium; metabolomics; microbial; microbiome; microbiome composition; microbiota; microorganism antigen; mitochondrial metabolism; mouse model; murine colitis; novel; preservation; response; small molecule; stem cell niche; therapeutic target

SUMMARY Inflammatory Bowel Disease (IBD) is a debilitating condition that contributes to high morbidity and poor quality of life. A risk factor for the development of IBD is a ‘leaky gut’ phenotype where elevated amounts of microbially- derived antigenic material traverse the gut epithelium into sub-epithelial compartments provoking a dysregulated inflammatory loop. Therefore, maintaining a strong intestinal epithelial barrier is vital to avoid overt gut inflammation. By extension, identifying the molecular mechanisms that function in preserving gut epithelial barrier integrity is critical for understanding optimal intestinal health. There is mounting evidence that bioactive metabolites generated by the gut microbiome exert profound influence on gut epithelial barrier integrity. However, we know little about how these bioactive metabolites mechanistically influence host biology. Employing mass spectrometry-based metabolomics platforms for analysis of small molecules, our research group demonstrated remarkable differences in the metabolite composition of germ-free and conventional mice, and identified novel small molecules of microbial origin. The most discriminative molecule was δ-valerobetaine (VB). VB structurally resembles γ-butyrobetaine, the immediate biosynthetic precursor to carnitine, which is required for mitochondrial fatty acid oxidation, suggesting a role for VB in controlling energy metabolism in the mitochondria. We also confirmed that VB is undetectable in germ-free mice and their mitochondria, but present in conventionalized mice and their mitochondria. In vivo and in vitro studies showed that VB inhibits mitochondrial fatty acid oxidation through decreasing cellular carnitine levels. Importantly, the intestinal stem cell (ISC) niche is tightly regulated by numerous host-derived and luminal-derived factors, while the plasticity of the ISC niche is associated with cellular metabolism and mitochondrial function. In addition, some gastrointestinal diseases such as IBD are characterized by modifications in mitochondrial function. In preliminary data, we show that VB administration to germ-free mice induces mitochondrial biogenesis in the gut epithelium, and induces cell proliferation in the intestinal crypt. We hypothesize that VB derived from the microbiome can influence mitochondrial bioenergetics in cells within the intestinal epithelium, and functions as a central integrator whereby the microbiota influences gut cell homeostasis, gut epithelia barrier integrity, and tissue restitution following injury. I will test this hypothesis by the following specific aims, 1) to characterize the effect of VB on mitochondria function in gut tissue homeostasis, and 2) to determine the impact of VB on gut epithelial restitution in murine injury models. These aims will be carried out using a variety of methods in which I will be trained, including 3D ex vivo organoid models, mouse models of colitis and epithelial restitution, and gnotobiotic mice. The long-term goal of this research is to understand the role of VB in gut health and identify the therapeutic potential of VB as a treatment for IBD.

总结 炎症性肠病（IBD）是一种使人衰弱的疾病，导致高发病率和低质量 生命IBD发展的一个危险因素是“漏肠”表型，其中微生物- 衍生的抗原物质穿过肠上皮进入上皮下区室， 炎症环因此，维持一个强大的肠上皮屏障是至关重要的，以避免明显的肠道 炎症通过扩展，确定在保护肠道上皮屏障中起作用的分子机制 完整性对于了解最佳肠道健康至关重要。越来越多的证据表明， 由肠道微生物组产生的代谢物对肠道上皮屏障完整性产生深远的影响。然而，在这方面， 我们对这些生物活性代谢物如何机械地影响宿主生物学知之甚少。就业质量 基于光谱的代谢组学平台用于分析小分子，我们的研究小组证明了 无菌小鼠和常规小鼠的代谢物组成存在显著差异， 微生物来源的小分子。最具鉴别力的分子是δ-戊酰甜菜碱（VB）。VB结构 类似于γ-丁基甜菜碱，肉毒碱的直接生物合成前体，这是线粒体所需的 脂肪酸氧化，表明VB在控制线粒体能量代谢中的作用。我们也 证实VB在无菌小鼠及其线粒体中检测不到，但在常规小鼠中存在 和它们的线粒体。体内和体外研究表明，VB抑制线粒体脂肪酸氧化 通过降低细胞内的肉毒碱水平重要的是，肠道干细胞（ISC）的小生境受到严格的调控， 许多宿主来源的和腔源性的因素，而ISC生态位的可塑性与 细胞代谢和线粒体功能。此外，一些胃肠道疾病，如IBD， 以线粒体功能的改变为特征。在初步的数据，我们表明，VB管理， 无菌小鼠诱导肠上皮细胞中的线粒体生物发生， 肠隐窝我们假设来自微生物组的VB可以影响线粒体生物能量学 在肠上皮细胞内，并作为一个中央整合器，从而微生物群影响 肠细胞稳态、肠上皮屏障完整性和损伤后的组织恢复。我将检验这个假设 通过以下具体目的，1）表征VB对肠组织中线粒体功能的影响 稳态，和2）确定VB对鼠损伤模型中肠上皮恢复的影响。这些 目标将使用各种方法进行，我将接受培训，包括3D离体类器官模型， 结肠炎和上皮恢复的小鼠模型，以及gnotobiotic小鼠。这项研究的长期目标是 了解VB在肠道健康中的作用，并确定VB作为IBD治疗的治疗潜力。