High-fat diet enhances stemness and tumorigenicity of intestinal progenitors
Ontology highlight
ABSTRACT: Little is known about how pro-obesity diets regulate tissue stem and progenitor cell function. Here we find that high fat diet (HFD)-induced obesity augments the numbers and function of Lgr5+ intestinal stem cells (ISCs) of the mammalian intestine. Like HFD, ex vivo treatment of intestinal organoid cultures with palmitic acid (PA), a constituent of the HFD, enhances the self-renewal potential of these organoid bodies. Mechanistically, HFD induces a robust peroxisome proliferator-activated receptor delta (PPAR-delta signature in intestinal stem and progenitor cells and pharmacologic activation of PPAR-delta recapitulates the effects that HFD has on these cells. Interestingly, HFD- and agonist-activated PPAR-delta signaling endows organoid-initiating capacity to non-stem cells and enforced PPAR-delta signaling permits these non-stem cells to form in vivo tumors upon loss of the tumor suppressor Apc. These findings highlight how diet-modulated PPAR-delta activation alters not only the function of intestinal stem and progenitor cells but also their capacity to initiate tumors. mRNA profiles of intestinal stem cells (GFP-Hi) and progenitors (GFP-Low) from WT or HFD fed mice were generated by deep sequencing using HiSeq 2000.
Project description:Little is known about how pro-obesity diets regulate tissue stem and progenitor cell function. Here we find that high fat diet (HFD)-induced obesity augments the numbers and function of Lgr5+ intestinal stem cells (ISCs) of the mammalian intestine. Like HFD, ex vivo treatment of intestinal organoid cultures with palmitic acid (PA), a constituent of the HFD, enhances the self-renewal potential of these organoid bodies. Mechanistically, HFD induces a robust peroxisome proliferator-activated receptor delta (PPAR-delta signature in intestinal stem and progenitor cells and pharmacologic activation of PPAR-delta recapitulates the effects that HFD has on these cells. Interestingly, HFD- and agonist-activated PPAR-delta signaling endows organoid-initiating capacity to non-stem cells and enforced PPAR-delta signaling permits these non-stem cells to form in vivo tumors upon loss of the tumor suppressor Apc. These findings highlight how diet-modulated PPAR-delta activation alters not only the function of intestinal stem and progenitor cells but also their capacity to initiate tumors.
Project description:Obesity is an established risk factor for cancer in many tissues such as the gastrointestinal tract. In the mammalian intestine, a pro-obesity high fat diet (HFD) promotes tumorigenesis in part by enhancing intestinal stem cell (ISC) numbers, proliferation and function. Although Ppar (Peroxisome proliferator-activated receptor) nuclear receptor activity has been proposed to mediate some of these effects in HFD ISCs, the exact role that different Ppar family members play in this process is unclear. Here, we find that in loss-of-function in vivo models, both Ppar family members alpha and delta contribute to the HFD response in ISCs. Mechanistically, both PPARs do so by robustly inducing a downstream fatty acid oxidation (FAO) metabolic program. Notably, pharmacologic and genetic disruption of CPT1a (the rate limiting enzyme of FAO) blunts the HFD phenotype in ISCs. Furthermore, just as HFD ISCs depend on CPT1a-mediated FAO, inhibition of CPT1a dampens the pro-tumorigenic consequences of a HFD on early tumor incidence and progression in the intestine. These findings demonstrate that inhibition of a HFD activated FAO program creates a therapeutic opportunity to counter the effects of a HFD on ISCs and intestinal tumorigenesis.
Project description:Obesity is an established risk factor for cancer in many tissues such as the gastrointestinal tract. In the mammalian intestine, a pro-obesity high fat diet (HFD) promotes tumorigenesis in part by enhancing intestinal stem cell (ISC) numbers, proliferation and function. Although Ppar (Peroxisome proliferator-activated receptor) nuclear receptor activity has been proposed to mediate some of these effects in HFD ISCs, the exact role that different Ppar family members play in this process is unclear. Here, we find that in loss-of-function in vivo models, both Ppar family members alpha and delta contribute to the HFD response in ISCs. Mechanistically, both PPARs do so by robustly inducing a downstream fatty acid oxidation (FAO) metabolic program. Notably, pharmacologic and genetic disruption of CPT1a (the rate limiting enzyme of FAO) blunts the HFD phenotype in ISCs. Furthermore, just as HFD ISCs depend on CPT1a-mediated FAO, inhibition of CPT1a dampens the pro-tumorigenic consequences of a HFD on early tumor incidence and progression in the intestine. These findings demonstrate that inhibition of a HFD activated FAO program creates a therapeutic opportunity to counter the effects of a HFD on ISCs and intestinal tumorigenesis.
Project description:Obesity is an established risk factor for cancer in many tissues such as the gastrointestinal tract. In the mammalian intestine, a pro-obesity high fat diet (HFD) promotes tumorigenesis in part by enhancing intestinal stem cell (ISC) numbers, proliferation and function. Although Ppar (Peroxisome proliferator-activated receptor) nuclear receptor activity has been proposed to mediate some of these effects in HFD ISCs, the exact role that different Ppar family members play in this process is unclear. Here, we find that in loss-of-function in vivo models, both Ppar family members alpha and delta contribute to the HFD response in ISCs. Mechanistically, both PPARs do so by robustly inducing a downstream fatty acid oxidation (FAO) metabolic program. Notably, pharmacologic and genetic disruption of CPT1a (the rate limiting enzyme of FAO) blunts the HFD phenotype in ISCs. Furthermore, just as HFD ISCs depend on CPT1a-mediated FAO, inhibition of CPT1a dampens the pro-tumorigenic consequences of a HFD on early tumor incidence and progression in the intestine. These findings demonstrate that inhibition of a HFD activated FAO program creates a therapeutic opportunity to counter the effects of a HFD on ISCs and intestinal tumorigenesis.
Project description:Carotenoids are naturally occurring pigments in plants responsible for the orange, yellow, and red color of fruits and vegetables. Carrots are one of the primary dietary sources of carotenoids. The biological activities of carotenoids in higher organisms are well documented in most tissues but not the large intestine. The gastrointestinal barrier acts as a line of defense against the systemic invasion of pathogenic bacteria, especially at the colonic level. Proteins involved in tight junction assembly between epithelial cells and mucus secretion from goblet cells are essential for maintaining intestinal barrier homeostasis. A high-fat diet can cause gut impairment by inducing barrier permeability, leading to low-grade chronic inflammation via metabolic endotoxemia. Our hypothesis for this study is that the dietary intake of carotenoid-rich foods can alleviate obesity-associated gut inflammation and strengthen the intestinal barrier function. Male C57BL/6J mice were randomized to one of four experimental diets for 20 weeks (n = 20 animals/group): Low-fat diet (LFD, 10% calories from fat), high-fat diet (HFD, 45% calories from fat), HFD with white carrot powder (HFD + WC), or HFD with orange carrot powder (HFD + OC). Colon tissues were harvested to analyze the biochemical effects of carotenoids in carrots. The distal sections were subjected to isobaric labeling-based quantitative proteomics in which tryptic peptides were labeled with tandem mass tags, followed by fractionation and LC-MS/MS analysis in an Orbitrap Eclipse Tribrid instrument. High-performance liquid chromatography results depicted that the HFD+WC pellets were carotenoid-deficient, and the HFD+OC pellets contained high concentrations of provitamin A carotenoids, specifically α-carotene and β-carotene. As a result of the quantitative proteomics, a total of 4410 differentially expressed proteins were identified. Intestinal barrier-associated proteins were highly upregulated in the HFD+OC group, particularly mucin-2 (MUC-2). Upon closer investigation into mucosal activity, other proteins related to MUC-2 functionality and tight junction management were upregulated by the HFD+OC dietary intervention. Carotenoid-rich foods may prevent high-fat diet-induced intestinal barrier disruption by promoting colonic mucus synthesis and secretion in mammalian organisms.
Project description:Objective Recent evidence indicates that the adult hematopoietic system is susceptible to diet-induced lineage skewing. It is not known whether the developing hematopoietic system is subject to metabolic programming via in utero high fat diet (HFD) exposure, an established mechanism of adult disease in several organ systems. We previously reported substantial losses in offspring liver size with prenatal HFD. As the liver is the main hematopoietic organ in the fetus, we asked whether the developmental expansion of the hematopoietic stem and progenitor cell (HSPC) pool is compromised by prenatal HFD and/or maternal obesity. Methods We used quantitative assays, progenitor colony formation, flow cytometry, transplantation, and gene expression assays with a series of dietary manipulations to test the effects of gestational high fat diet and maternal obesity on the day 14.5 fetal liver hematopoietic system. Results Maternal obesity, particularly when paired with gestational HFD, restricts physiological expansion of fetal HSPCs while promoting the opposing cell fate of differentiation. Importantly, these effects are only partially ameliorated by gestational dietary adjustments for obese dams. Competitive transplantation reveals compromised repopulation and myeloid-biased differentiation of HFD-programmed HSPCs to be a niche-dependent defect, apparent in HFD-conditioned male recipients. Fetal HSPC deficiencies coincide with perturbations in genes regulating metabolism, immune and inflammatory processes, and stress response, along with downregulation of genes critical for hematopoietic stem cell self-renewal and activation of pathways regulating cell migration. Conclusions Our data reveal a previously unrecognized susceptibility to nutritional and metabolic developmental programming in the fetal HSPC compartment, which is a partially reversible and microenvironment-dependent defect perturbing stem and progenitor cell expansion and hematopoietic lineage commitment. Examination of differentially expressed genes between gestational day 15 (+/- 0.5 days) C57BL/6 mouse fetal livers from diet-induced (60% fat diet) obese or control female mice.
Project description:To assess whether changes in islet gene expression contribute to differences in phenotypes in response to high fat diet or tretament with pioglitazone, Agilent Whole Mouse Genome Oligo Microarrays were performed on RNA isolated from islets of 4 mice per each treatment group for discovery analysis of gene expression. Male 8 week-old BL6 and BLKS mice were fed normal chow (18% kcal from fat), HFD (42% kcal from fat), or HFD supplemented with the PPAR-γ agonist pioglitazone (PIO) (140 mg PIO/kg diet) for 16 weeks.
Project description:Glioblastoma (GBM) remains among the deadliest of human malignancies, and the emergence of the cancer stem cell (CSC) phenotype represents a major challenge to durable treatment response. Because the environmental and lifestyle factors that impact CSC populations are not clear, we sought to understand the consequences of diet on CSC enrichment. We evaluated disease progression in mice fed an obesity-inducing high-fat diet (HFD) versus a low-fat, control diet. HFD resulted in hyper-aggressive disease accompanied by CSC enrichment and shortened survival. HFD drove intracerebral accumulation of saturated fats, which inhibited the production of the cysteine metabolite and gasotransmitter, hydrogen sulfide (H2S). H2S functions principally through protein S-sulfhydration and regulates multiple programs including bioenergetics and metabolism. Inhibition of H2S increased proliferation and chemotherapy resistance, whereas treatment with H2S donors led to death of cultured GBM cells and stasis of GBM tumors in vivo. GBM specimens present an overall reduction in protein S-sulfhydration, primarily associated with proteins regulating cellular metabolism. These findings provide new evidence that diet modifiable H2S signaling serves to suppress GBM by restricting metabolic fitness, while its loss triggers CSC enrichment and disease acceleration. Interventions augmenting H2S bioavailability concurrent with GBM standard of care may improve outcomes for GBM patients.
Project description:Diet-induced obesity is reported to induce a phenotypic switch in adipose tissue macrophages from an antiinflammatory M2 state to a proinflammatory M1 state. Telmisartan, an angiotensin II type 1 receptor antagonist and a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist, reportedly has beneficial effects on insulin sensitivity. We studied the effects of telmisartan on the adipose tissue macrophage phenotype in high fat-fed mice. Telmisartan was administered for 5 weeks to high fat-fed C57BL/6 mice. Insulin sensitivity, macrophage infiltration, and the gene expressions of M1 and M2 markers in epididymal fat tissues were examined. Insulin- or a glucose-tolerance test showed that telmisartan treatment improved insulin resistance, decreasing the body weight gain, visceral fat weight and adipocyte size without affecting the amount of food intake. Telmisartan treatment reduced the number of CD11c-positive cells and crown-like structures. Telmisartan reduced the mRNA expressions of M1 macrophage markers, such as TNF-alpha and IL-6, and increased the expression of M2 markers, such as IL-10 and Mgl2. The reduction of M1 macrophage markers, as well as the increased gene expression of M2 markers especially IL-10, is a possible mechanism for the improvement of insulin sensitivity by telmisartan. Six-week-old male C57BL/6J mice were purchased from CLEA Japan. The mice were fed a chow that contained 10% of its calories from fat (control) or a high-fat diet (HFD) that contained 30% of its calories from fat for 24 weeks. The high fat-fed mice were randomized to 3 groups. Either telmisartan (~3 mg/kg/day) in drinking water (HFD+Tel), candesartan (~3 mg/kg/day) in drinking water (HFD+Can), or a HFD without any drugs (HFD) was administered for the next 5 weeks. Two mice were treated per group. Epididymal adipose tissues were rapidly removed from each mouse. Gene expression in epididymal fat tissue was analyzed using a GeneChip® system with the Mouse Genome 430 2.0 Array, which was spotted with 45,101 probe sets (Affymetrix, Santa Clara, CA, USA). Sample preparation for the array hybridization was performed according to the manufacturer’s instructions. In short, 5 μg of total RNA was used to synthesize double-stranded cDNA using the GeneChip® Expression 3′-Amplification Reagents One-Cycle cDNA Synthesis Kit (Affymetrix). Biotin-labeled cRNA was then synthesized from the cDNA using GeneChip® Expression 3′-Amplification Reagents for IVT Labeling (Affymetrix). After fragmentation, the biotinylated cRNA was hybridized to arrays at 45 °C for 16 h. The arrays were washed, stained with streptavidin-phycoerythrin, and scanned using a probe array scanner. The scanned chip was analyzed using the GeneChip Analysis Suite software (Affymetrix). Hybridization intensity data were converted into a presence/absence call for each gene, and changes in gene expression between experiments were detected by a comparison analysis. Data was shown as the fold change relative to the expression level of normal chow-fed mice.
Project description:We developed a compartmental model of the small intestinal epithelium that describes stem and progenitor cell proliferation and differentiation and cell migration onto the villus. The model includes a negative feedback loop from villus cells to regulate crypt proliferation and integrates heterogeneous epithelial-related processes, such as the transcriptional profile, citrulline kinetics and probability of diarrhea.