Where There Is Fat There Is Fibrosis: Elucidating the Mechanisms of Creeping Fat-Driven Stricture Formation
ELSEVIER SCIENCE INC. 2021: S65
View details for Web of Science ID 000718303100105
Adipocytes In Dermal Wounds Undergo Conversion To Pro-fibrotic Fibroblasts That Contribute To Scar Formation
WILEY. 2021: A31
View details for Web of Science ID 000650720500078
A Surgical Model for Investigating the Role of Creeping Fat in Intestinal Fibrosis
ELSEVIER SCIENCE INC. 2020: S50–S51
View details for Web of Science ID 000582792300070
Ketone Body Signaling Mediates Intestinal Stem Cell Homeostasis and Adaptation to Diet
2019; 178 (5): 1115-+
Little is known about how metabolites couple tissue-specific stem cell function with physiology. Here we show that, in the mammalian small intestine, the expression of Hmgcs2 (3-hydroxy-3-methylglutaryl-CoA synthetase 2), the gene encoding the rate-limiting enzyme in the production of ketone bodies, including beta-hydroxybutyrate (βOHB), distinguishes self-renewing Lgr5+ stem cells (ISCs) from differentiated cell types. Hmgcs2 loss depletes βOHB levels in Lgr5+ ISCs and skews their differentiation toward secretory cell fates, which can be rescued by exogenous βOHB and class I histone deacetylase (HDAC) inhibitor treatment. Mechanistically, βOHB acts by inhibiting HDACs to reinforce Notch signaling, instructing ISC self-renewal and lineage decisions. Notably, although a high-fat ketogenic diet elevates ISC function and post-injury regeneration through βOHB-mediated Notch signaling, a glucose-supplemented diet has the opposite effects. These findings reveal how control of βOHB-activated signaling in ISCs by diet helps to fine-tune stem cell adaptation in homeostasis and injury.
View details for DOI 10.1016/j.cell.2019.07.048
View details for Web of Science ID 000482191000010
View details for PubMedID 31442404
View details for PubMedCentralID PMC6732196
Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and Aging.
Cell stem cell
2018; 22 (5): 769–78.e4
Diet has a profound effect on tissue regeneration in diverse organisms, and low caloric states such as intermittent fasting have beneficial effects on organismal health and age-associated loss of tissue function. The role of adult stem and progenitor cells in responding to short-term fasting and whether such responses improve regeneration are not well studied. Here we show that a 24 hr fast augments intestinal stem cell (ISC) function in young and aged mice by inducing a fatty acid oxidation (FAO) program and that pharmacological activation of this program mimics many effects of fasting. Acute genetic disruption of Cpt1a, the rate-limiting enzyme in FAO, abrogates ISC-enhancing effects of fasting, but long-term Cpt1a deletion decreases ISC numbers and function, implicating a role for FAO in ISC maintenance. These findings highlight a role for FAO in mediating pro-regenerative effects of fasting in intestinal biology, and they may represent a viable strategy for enhancing intestinal regeneration.
View details for DOI 10.1016/j.stem.2018.04.001
View details for PubMedID 29727683
View details for PubMedCentralID PMC5940005
High-fat diet enhances stemness and tumorigenicity of intestinal progenitors.
2016; 531 (7592): 53–58
Little is known about how pro-obesity diets regulate tissue stem and progenitor cell function. Here we show that high-fat diet (HFD)-induced obesity augments the numbers and function of Lgr5(+) intestinal stem cells of the mammalian intestine. Mechanistically, a HFD induces a robust peroxisome proliferator-activated receptor delta (PPAR-δ) signature in intestinal stem cells and progenitor cells (non-intestinal stem cells), and pharmacological activation of PPAR-δ recapitulates the effects of a HFD on these cells. Like a HFD, ex vivo treatment of intestinal organoid cultures with fatty acid constituents of the HFD enhances the self-renewal potential of these organoid bodies in a PPAR-δ-dependent manner. Notably, HFD- and agonist-activated PPAR-δ signalling endow organoid-initiating capacity to progenitors, and enforced PPAR-δ signalling permits these progenitors to form in vivo tumours after loss of the tumour suppressor Apc. These findings highlight how diet-modulated PPAR-δ activation alters not only the function of intestinal stem and progenitor cells, but also their capacity to initiate tumours.
View details for DOI 10.1038/nature17173
View details for PubMedID 26935695
View details for PubMedCentralID PMC4846772
mTORC1 in the Paneth cell niche couples intestinal stem-cell function to calorie intake
2012; 486 (7404): 490–U87
How adult tissue stem and niche cells respond to the nutritional state of an organism is not well understood. Here we find that Paneth cells, a key constituent of the mammalian intestinal stem-cell (ISC) niche, augment stem-cell function in response to calorie restriction. Calorie restriction acts by reducing mechanistic target of rapamycin complex 1 (mTORC1) signalling in Paneth cells, and the ISC-enhancing effects of calorie restriction can be mimicked by rapamycin. Calorie intake regulates mTORC1 in Paneth cells, but not ISCs, and forced activation of mTORC1 in Paneth cells during calorie restriction abolishes the ISC-augmenting effects of the niche. Finally, increased expression of bone stromal antigen 1 (Bst1) in Paneth cells—an ectoenzyme that produces the paracrine factor cyclic ADP ribose—mediates the effects of calorie restriction and rapamycin on ISC function. Our findings establish that mTORC1 non-cell-autonomously regulates stem-cell self-renewal, and highlight a significant role of the mammalian intestinal niche in coupling stem-cell function to organismal physiology.
View details for DOI 10.1038/nature11163
View details for Web of Science ID 000305760600034
View details for PubMedID 22722868
View details for PubMedCentralID PMC3387287