Elucidating the role of fasting in intestinal stemness and tissue regeneration

阐明禁食在肠道干性和组织再生中的作用

基本信息

批准号：
10333023
负责人：
Chia-Wei Cheng
金额：
$ 24.9万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-03-02 至 2024-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10333023
关键词：
3-hydroxy-3-methylglutaryl-coenzyme A Affect Agonist Biological Assay Cell Lineage Data Defect Enzymes Fasting Foundations Genetic Transcription Germ-Free Health Homeostasis Human Human body Injury Intervention Intestines Ketone Bodies Ketones LGR5 gene Ligase Mediating Mediator of activation protein Metabolic Metabolism Mus Organ Organoids PPAR alpha PPAR delta Pathway interactions Pharmacology Play Process Production Radiation Regimen Reporter Role Signal Transduction Technology Testing Therapeutic Tissues Whole Organism adult stem cell beta-Hydroxybutyrate epithelium regeneration fatty acid oxidation gut microbiome gut microbiota improved in vivo insight intestinal epithelium intestinal injury ketogenesis ketogentic microbiome composition mouse model notch protein novel programs regeneration function response single-cell RNA sequencing stem cell aging stem cell function stem cells stemness tissue regeneration tissue repair

项目摘要

7. Project Summary/Abstract Fasting interventions improve health in mice and in humans. Given that adult stem cells coordinate tissue adaptation, understanding the mechanism(s) that mediate the fasting response has important implications for enhancing tissue repair after injury and in aging where stem cell function declines. In the mammalian intestine, LGR5+ intestinal stem cells (ISCs) drive the rapid renewal of the intestinal lining. We previously showed that fasting augments ISC function by inducing a peroxisome proliferator-activated receptor delta (PPARδ) driven fatty acid oxidation (FAO) program. However, the in vivo role of PPARδ or downstream effector(s) of FAO metabolism that mediate the ISC fasting response remains unknown. In this proposal, we will test the hypotheses that 1) PPARδ signaling is necessary for the in vivo ISC fasting response, 2) PPARδ- activated FAO stimulates intestinal stemness through the production of the ketone body β-hydroxybutyrate (βOHB) in fasting, and 3) changes in the gut microbiome are necessary, sufficient or both in mediating the ISC fasting response. In support of these notions, we find that PPARδ agonist treatment emulates the effects of fasting on ISCs. Furthermore, we find that enzymes of the ketogenic pathway that produce the ketone metabolite βOHB, including its rate-limiting step HMGCS2 (3-hydroxy-3-methylglutaryl-CoA synthetase 2), highly enrich for LGR5+ ISCs. Also, elevation of HMGCS2 expression and βOHB levels upon fasting correlates with enhanced ISC function while loss of HMGCS2 dampens ISC capacity to propagate organoids and biases their differentiation towards the secretory lineage. Importantly, these deficits can be rectified by βOHB treatment in cultures. Thus, these observations provide a possible pathway for fasting through the modulation of HMGCS2-mediated ketogenesis to augment the regenerative function of ISCs. Lastly, fasting regimens are known to alter the gut microbiome composition but the extent to which these changes underlie the ISC fasting response requires elucidation. Remaining questions regarding the specific in vivo role of PPARδ as an upstream regulator of HMGCS2 expression and ISC fasting response, the in vivo role of HMGCS2 and βOHB as mediators of intestinal stemness and the contribution of the fasting gut microbiota in these processes.

7. 项目总结/摘要鉴于成体干细胞的协调作用，禁食干预可以改善小鼠和人类的健康。组织适应，了解介导禁食反应的机制具有重要意义对增强损伤后组织修复和干细胞功能下降的衰老的影响。在哺乳动物肠道中，LGR5+ 肠道干细胞 (ISC) 驱动肠道内壁的快速更新。先前表明，禁食通过诱导过氧化物酶体增殖物激活受体来增强 ISC 功能 δ（PPARδ）驱动脂肪酸氧化（FAO）程序，但PPARδ在体内的作用还是下游。介导 ISC 禁食反应的 FAO 代谢效应器仍然未知。将检验以下假设：1) PPARδ 信号传导对于体内 ISC 禁食反应是必需的，2) PPARδ- 活化的FAO通过酮体β-羟基丁酸的产生刺激肠道干性 (βOHB) 禁食，以及 3) 肠道微生物组的变化对于介导 ISC 是必要的、充分的或两者兼而有之为了支持这些观点，我们发现 PPARδ 激动剂治疗模拟了空腹反应的效果。此外，我们发现生酮途径中的酶可以产生酮。代谢物 βOHB，包括其限速步骤 HMGCS2（3-羟基-3-甲基戊二酰辅酶A合成酶 2）， LGR5+ ISC 高度富集，并且空腹时 HMGCS2 表达和 βOHB 水平升高相关。 ISC 功能增强，而 HMGCS2 的缺失会抑制 ISC 传播类器官和偏差的能力重要的是，这些缺陷可以通过 βOHB 来纠正。因此，这些观察结果为通过调节禁食提供了可能的途径。 HMGCS2介导的生酮作用以增强ISC的再生功能最后，禁食方案是。已知会改变肠道微生物组的组成，但这些变化在多大程度上是 ISC 禁食的基础关于 PPARδ 作为一种药物的具体体内作用，尚需进一步阐明。 HMGCS2 表达和 ISC 禁食反应的上游调节因子，HMGCS2 和 βOHB 的体内作用作为肠道干性的介质以及空腹肠道微生物群在这些过程中的贡献。