Intestinal lipid metabolism regulates absorption and surface of gut epithelium
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE152056 | GEO | 2021/09/02
REPOSITORIES: GEO
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Project description:Intestinal surface changes in size and function, but what propels these alterations and what are their metabolic consequences is unknown. Here we show that the food amount is a major positive determinant of the gut surface area contributing to an increased absorptive function, reversible by reducing daily food. While several upregulated intestinal energetic pathways are dispensable, the intestinal lipid metabolism is instead necessary for the genetic and environment overeating–induced increase of the gut absorptive capacity. In presence of dietary lipids, intestinal PPARα knock-out or its pharmacological antagonism suppress intestinal crypt expansion and shorten villi in mice and in human intestinal biopsies, diminishing the post-prandial triglyceride transport and nutrient uptake. Intestinal PPARα ablation limits systemic lipid absorption and restricts lipid droplet expansion and PLIN2 levels, critical for droplet formation. This improves the lipid metabolism, and reduces body adiposity and liver steatosis, suggesting an alternative target for treating obesity.
2021-08-20 | GSE182348 | GEO
Project description:Background: The selective absorption of nutrients and other food constituents in the small intestine is mediated by a group of transport proteins and metabolic enzymes, often collectively called ‘intestinal barrier proteins’. An important receptor that mediates the effects of dietary lipids on gene expression is the peroxisome proliferator-activated receptor alpha (PPARα), which is abundantly expressed in enterocytes. In this study we examined the effects of acute nutritional activation of PPARα on expression of genes encoding intestinal barrier proteins. To this end we used triacylglycerols composed of identical fatty acids in combination with gene expression profiling in wild-type and PPARα-null mice. Treatment with the synthetic PPARα agonist WY14643 served as reference. Results: We identified 74 barrier genes that were PPARα-dependently regulated 6 hours after activation with WY14643. For eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and oleic acid (OA) these numbers were 46, 41, and 19, respectively. The overlap between EPA-, DHA-, and WY14643-regulated genes was considerable, whereas OA treatment showed limited overlap. Functional implications inferred form our data suggested that nutrient-activated PPARα regulated transporters and phase I/II metabolic enzymes were involved in a) fatty acid oxidation, b) cholesterol, glucose, and amino acid transport and metabolism, c) intestinal motility, and d) oxidative stress defense. Conclusion: We identified intestinal barrier genes that were PPARα-dependently regulated after acute activation by fatty acids.This knowledge provides a better understanding of the impact dietary fat has on the barrier function of the gut, identifies PPARα as an important factor controlling this key function, and underscores the importance of PPARα for nutrient-mediated gene regulation in intestine. Keywords: metabolic state analysis
2008-05-22 | GSE9533 | GEO
Project description:Nuclear receptor activation in liver leads to coordinated alteration of the expression of multiple gene products with attendant phenotypic changes of hepatocytes. Peroxisome proliferators including endogenous fatty acids, environmental chemicals, and drugs induce a multi-enzyme metabolic response that affects lipid and fatty acid processing. We studied the signaling network for the peroxisome proliferator-associated receptor alpha (PPARα) in primary human hepatocytes using the selective PPARα ligand, GW7647. We measured gene expression over multiple concentrations and times and conducted ChIP-seq studies at 2 and 24 hours to assess genomic binding of PPARα. Over all treatments there were 192 genes differentially expressed. Of these only 51% showed evidence of PPARα binding – either directly at PPARα response elements or via alternative mechanisms. Almost half of regulated genes had no PPARα binding. We then developed two novel bioinformatics methods to visualize the dose-dependent activation of both the transcription factor circuitry for PPARα and the downstream metabolic network in relation to functional annotation categories. Available databases identified several key transcription factors involved with the non-genomic targets after GW7647 treatment, including SP1, STAT1, ETS1, ERα, and HNF4α. The linkage from PPARα binding through gene expression likely requires intermediate protein kinases to activate these transcription factors. We found enrichment of functional annotation categories for organic acid metabolism and cell lipid metabolism among the differentially expressed genes. Lipid transport processes showed enrichment at the highest concentration of GW7647 (10μM). While our strategy for mapping transcriptional networks is evolving, these approaches are necessary in moving from toxicogenomic methods that derive signatures of activity to methods that establish pathway structure, showing the coordination of the activated nuclear receptor with other signaling pathways. Primary hepatocytes from four donors were exposed to 0, 0.001, 0.01, 0.1, 1.0, or 10.0μM GW7647 for 2, 6, 12, 24, or 72 hours.
2013-12-18 | E-GEOD-53399 | biostudies-arrayexpress
Project description:Dyslipidemia is a main driver of cardiovascular diseases. The ability of macrophages to scavenge excess lipids implicate them as mediators in this process and understanding the mechanisms underlying macrophage lipid metabolism is key to the development of new treatments. Here we investigated how adipose tissue macrophages (ATMs) regulate post-prandial cholesterol transport. Single-cell RNA sequencing demonstrated that ingestion of lipids led to specific transcriptional activation of a population of resident ATMs expressing Lyve1, Tim4 and ABCA1.
2021-03-18 | GSE168278 | GEO
Project description:Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic diseases globally and nonalcoholic steatohepatitis is its progressive stage with limited therapeutic options. Here a role for intestinal peroxisome proliferator-activated receptor α (PPARα)-fatty acid binding protein 1 (FABP1) in obesity-associated metabolic syndrome, fatty liver and nonalcoholic steatohepatitis via modulating dietary fat absorption was uncovered. Intestinal PPARα is highly activated accompanied by marked upregulation of FABP1 by high-fat diet (HFD) in mice and obese humans. Intestine-specific PPARα or FABP1 disruption in mice decreases HFD-induced obesity, fatty liver and nonalcoholic steatohepatitis and intestinal PPARα disruption fails to further decrease obesity and NASH. Chemical PPARα antagonism improves metabolic disorders depending on the presence of intestinal PPARα or FABP1. Translationally, GW6471 decreases human PPARα-driven intestinal fatty acid uptake and therapeutically improves obesity in PPARA-humanized, but not Ppara-null, mice. These results suggest that intestinal PPARα-FABP1 axis could be a therapeutic target for NASH.
2022-09-01 | GSE190140 | GEO
Project description:A diet rich in dietary fiber and polyphenols supports the normal intestinal barrier function crucial for intestinal and overall health. Birch wood-derived fiber containing glucuronoxylans (GX)- and polyphenols have the potential in multiple food technological applications and have favorable effects on gut microbiota and colonic metabolism. However, their impact on intestinal barrier function is unknown. To elucidate their potential as new intestinal health-supporting food ingredients, we investigated the effect of GX- and polyphenol-rich extract (GXpoly ) and highly purified GX-rich extract (pureGX) on the gene expression of the colon mucosa.
2023-12-01 | GSE230139 | GEO
Project description:Circulating levels of the gut microbe-derived metabolite trimethylamine-N-oxide(TMAO) have recently been linked to cardiovascular disease (CVD) risk. Here we performed transcriptional profiling in mouse models of altered reverse cholesterol transport (RCT), and serendipitously identified the TMAO-generating enzyme flavin monooxygenase 3 (FMO3) as a powerful modifier of cholesterol metabolism and RCT. Knockdown of FMO3 in cholesterol-fed mice alters biliary lipid secretion, blunts intestinal cholesterol absorption, and limits the production of hepatic oxysterols and cholesteryl esters. Furthermore, FMO3 knockdown stimulates basal and liver X receptor (LXR)-stimulated macrophage RCT, thereby improving cholesterol balance. Conversely, FMO3 knockdown exacerbates hepatic ER stress and inflammation in part by decreasing hepatic oxysterol levels and subsequent LXR activation. FMO3 is thus identified as a central integrator of hepatic cholesterol and triacylglycerol metabolism, inflammation, and ER stress. These studies suggest that the gut microbiota-driven TMA/FMO3/TMAO pathway is a key regulator of lipid metabolism and inflammation. To identify potential regulators of macrophage reverse cholesterol transport (RCT), liver was isolated from two independent mouse models where the non-biliary RCT pathway known as transintestinal cholesterol excretion (TICE) was either chronically (NPC1L1-liver-transgenic mice) or acutely (ACAT2 antisense oligonucleotide treatment) stimulated. Total RNA was isolated and gene expression levels were profiled on the Affymetrix GeneAtlas MG-430 PM Array Strip (Affymetrix; Santa Clara, CA, USA)
2014-12-19 | E-GEOD-64326 | biostudies-arrayexpress
Project description:Nuclear receptor activation in liver leads to coordinated alteration of the expression of multiple gene products with attendant phenotypic changes of hepatocytes. Peroxisome proliferators including endogenous fatty acids, environmental chemicals, and drugs induce a multi-enzyme metabolic response that affects lipid and fatty acid processing. We studied the signaling network for the peroxisome proliferator-associated receptor alpha (PPARα) in primary human hepatocytes using the selective PPARα ligand, GW7647. We measured gene expression over multiple concentrations and times and conducted ChIP-seq studies at 2 and 24 hours to assess genomic binding of PPARα. Over all treatments there were 192 genes differentially expressed. Of these only 51% showed evidence of PPARα binding – either directly at PPARα response elements or via alternative mechanisms. Almost half of regulated genes had no PPARα binding. We then developed two novel bioinformatics methods to visualize the dose-dependent activation of both the transcription factor circuitry for PPARα and the downstream metabolic network in relation to functional annotation categories. Available databases identified several key transcription factors involved with the non-genomic targets after GW7647 treatment, including SP1, STAT1, ETS1, ERα, and HNF4α. The linkage from PPARα binding through gene expression likely requires intermediate protein kinases to activate these transcription factors. We found enrichment of functional annotation categories for organic acid metabolism and cell lipid metabolism among the differentially expressed genes. Lipid transport processes showed enrichment at the highest concentration of GW7647 (10μM). While our strategy for mapping transcriptional networks is evolving, these approaches are necessary in moving from toxicogenomic methods that derive signatures of activity to methods that establish pathway structure, showing the coordination of the activated nuclear receptor with other signaling pathways.
2013-12-18 | GSE53399 | GEO
Project description:To analyse the peptidomics of mouse enteroendocrine cells (EECs) and human gastrointestinal (GI) tissue and identify novel gut derived peptides. High resolution nano-flow liquid chromatography mass spectrometry (LCMS) was performed on (i) flow-cytometry purified NeuroD1 positive cells from mouse and homogenised human intestinal biopsies, (ii) supernatants from primary murine intestinal cultures, (iii) intestinal homogenates from mice fed high fat diet. Candidate bioactive peptides were selected on the basis of species conservation, high expression/biosynthesis in EECs and evidence of regulated secretion in vitro. Candidate novel gut-derived peptides were chronically administered to mice to assess effects on food intake and glucose tolerance.
2021-03-29 | PXD024050 | Pride
Project description:Purpose: While various functions of peripheral serotonin are known, the direct role of serotonin in regulating hepatic lipid metabolism in vivo is not well understood. We studied whether serotonin directly acts on liver to regulate lipid metabolism. Methods: Methods: 12 weeks aged liver-specific Htr2a KO (Albumin-Cre+/-; Htr2aflox/flox, herein named Htr2a LKO) mice and wildtype (WT) littermates were fed a high-fat diet (HFD, 60% fat calories) for 8 weeks. Results: Hepatic lipid droplet accumulation, NAFLD activity score, and hepatic triglyceride levels were dramatically reduced in HFD-fed Htr2a LKO mice compared to WT littermates. Conclusions: Gut-derived serotonin is a direct regulator of hepatic lipid metabolism via a gut TPH1-liver HTR2A endocrine axis. And shows promise as a novel drug target to ameliorate NAFLD with minimal systemic metabolic effects.
2018-11-27 | GSE120662 | GEO