Ketone body metabolites in intestinal stem cell homeostasis and disease.

肠道干细胞稳态和疾病中的酮体代谢。

• 批准号: 10489276
• 负责人: Jessica Elizabeth Stewart Shay
• 金额: $ 8.08万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10489276
• 关键词: 3-hydroxy-3-methylglutaryl-coenzyme A; Acetoacetates; Acetyl Coenzyme A; Age; Cell division; Cells; Citric Acid Cycle; Coenzyme A; Cues; Data; Diet; Disease; Environment; Enzymes; Epithelial Cells; Equilibrium; Fasting; Fatty Acids; G-Protein-Coupled Receptors; Genetic; Genetic Models; Genetic Transcription; Health; Histone Deacetylase; Histone Deacetylase Inhibitor; Homeostasis; Human; In Vitro; Inflammation; Injury; Intestines; Isotope Labeling; Ketone Bodies; Ketones; Knockout Mice; Label; Leucine-Rich Repeat; Ligase; Longevity; Maps; Mediating; Metabolic; Mitochondria; Modeling; Mus; Natural regeneration; Notch Signaling Pathway; Nutritional; Oxidoreductase; Pathway interactions; Physiological; Process; Production; Publishing; Role; Signal Pathway; Signal Transduction; Techniques; Technology; Testing; Therapeutic; Tissues; Transferase; age related; aged; base; beta-Hydroxybutyrate; experimental study; fatty acid oxidation; improved; in vivo; inhibitor therapy; intestinal crypt; intestinal epithelium; ketogentic; metabolomics; mouse model; novel; oxidation; oxidative damage; programs; rapid technique; response; response to injury; stem cell function; stem cell homeostasis; stem cells; stemness; succinyl-coenzyme A; tissue injury; tissue regeneration

Project Summary/Abstract Diet has a profound impact on organismal health. Fasting improves human health in part by reducing inflammation, decreasing oxidative damage and extending longevity, however, the mechanisms by which fasting improves intestinal regeneration remains poorly understood. The intestinal epithelium renews fastidiously every 5-7 days via Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5+) expressing intestinal stem cells (ISCs) found at the base of the intestinal crypt. LGR5+ ISCs balance differentiation and epithelial cell divisions to influence tissue regeneration by integrating metabolic and signaling cues from their environment like diet. Fasting has a profound effect on ISC function in young and aged mice and can improve the age-associated decline in tissue regeneration through the induction of fatty acid oxidation (FAO), a process that oxidizes fatty acids into acetyl-CoA units. In addition, LGR5+ ISCs strongly express 3-hydroxy-3-methylglutaryl-CoA synthetase 2 (HMGCS2), the rate-limiting enzyme in the ketogenic pathway whereby acetyl-CoA units are converted to ketone bodies such as beta-hydroxybutyrate (bOHB) and acetoacetate (AcAc). Mechanistically, bOHB reinforces the NOTCH signaling pathway by inhibiting class I histone-deacetylases (HDACs) to instruct ISC cell fate decisions. These findings further support a nuanced relationship between host nutritional state and stem cell function whereby dynamic control of ISC bOHB levels enable their rapid adaptation to diverse physiological states such as fasting. Other roles for ISC-derived ketone body metabolites have yet to be elucidated and, as such, we propose that bOHB and AcAc function as distinct signaling metabolites regulating ISC fasting responses (Aim 1) and have unique roles as energetic substrates (Aim 2). To test this hypothesis, we will use key genetic mouse models to understand how perturbed bOHB/AcAc ratios alter intestinal stem cell function in vivo and in vitro (Aim 1), as well as labelled substrate administration and novel techniques for rapid mitochondrial isolation to determine key ISC metabolic adaptations to fasting (Aim 2). Taken together, the experiments proposed will mechanistically delineate the signaling and energetic roles of ketone body metabolites on intestinal stemness and improve our understanding of how the fasting response via ketone bodies influences intestinal regeneration. We expect this approach will identify therapeutic options exploiting ketone bodies and the signaling and energetic pathways engaged by them to enhance intestinal regeneration in cases of injury and age-related decline of stem cell function.

项目摘要/摘要 饮食对生物健康有深远的影响。禁食通过减少的部分改善人类健康 炎症，减少氧化损伤并延长寿命，但是，禁食的机制 改善肠道再生仍然很少了解。每个肠上皮都仔细地更新 5-7天通过富含亮氨酸重复的G蛋白耦合受体5（LGR5+）表达肠茎 在肠道隐窝的底部发现的细胞（ISC）。 LGR5+ ISC平衡分化和上皮细胞 通过整合来自环境的代谢和信号线索来影响组织再生的分裂 饮食。禁食对年轻小鼠的ISC功能有深远的影响，可以改善与年龄相关的 通过诱导脂肪酸氧化（FAO）来减少组织再生，这一过程可氧化脂肪 酸到乙酰辅酶A单元。此外，LGR5+ ISC强烈表达3-羟基-3-甲基戊二酰-COA 合成酶2（HMGCS2），乙酰辅酶A单元的生酮途径中的速率限制酶 转化为酮体，例如β-羟基丁酸（BOHB）和乙酸乙酸酯（ACAC）。机械上， BOHB通过抑制I类组蛋白二乙酰酶（HDACS）来加强Notch信号通路 ISC细胞命运决定。这些发现进一步支持了宿主营养状态与 干细胞功能，使ISC BOHB水平的动态控制能够快速适应多样化 生理状态，例如禁食。 ISC衍生的酮体代谢产物的其他角色尚未 阐明，因此，我们提出BOHB和ACAC作为调节的不同信号代谢物的作用 ISC禁食响应（AIM 1），并且具有独特的作用，作为能量底物（AIM 2）。为了检验这一假设， 我们将使用关键的遗传小鼠模型来了解受干扰的BOHB/ACAC比率如何改变肠道干细胞 在体内和体外功能（AIM 1），以及标记的底物给药和快速的新技术 线粒体隔离以确定关键的ISC代谢适应禁食（AIM 2）。总的来说， 提出的实验将机械地描述酮体代谢物的信号传导和能量作用 关于肠干，并提高我们对酮体禁食反应的理解 肠再生。我们希望这种方法将确定利用酮体的治疗选择，并且 它们参与的信号传导和能量途径，以增强受伤和 与年龄相关的干细胞功能下降。