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Vemuri K, Radi SH, Sladek FM, Verzi MP. Multiple roles and regulatory mechanisms of the transcription factor HNF4 in the intestine. Front Endocrinol (Lausanne) 2023; 14:1232569. [PMID: 37635981 PMCID: PMC10450339 DOI: 10.3389/fendo.2023.1232569] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/24/2023] [Indexed: 08/29/2023] Open
Abstract
Hepatocyte nuclear factor 4-alpha (HNF4α) drives a complex array of transcriptional programs across multiple organs. Beyond its previously documented function in the liver, HNF4α has crucial roles in the kidney, intestine, and pancreas. In the intestine, a multitude of functions have been attributed to HNF4 and its accessory transcription factors, including but not limited to, intestinal maturation, differentiation, regeneration, and stem cell renewal. Functional redundancy between HNF4α and its intestine-restricted paralog HNF4γ, and co-regulation with other transcription factors drive these functions. Dysregulated expression of HNF4 results in a wide range of disease manifestations, including the development of a chronic inflammatory state in the intestine. In this review, we focus on the multiple molecular mechanisms of HNF4 in the intestine and explore translational opportunities. We aim to introduce new perspectives in understanding intestinal genetics and the complexity of gastrointestinal disorders through the lens of HNF4 transcription factors.
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Affiliation(s)
- Kiranmayi Vemuri
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
- Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States
| | - Sarah H. Radi
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
- Department of Biochemistry, University of California, Riverside, Riverside, CA, United States
| | - Frances M. Sladek
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Michael P. Verzi
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
- Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States
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2
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Heppert JK, Lickwar CR, Tillman MC, Davis BR, Davison JM, Lu HY, Chen W, Busch-Nentwich EM, Corcoran DL, Rawls JF. Conserved roles for Hnf4 family transcription factors in zebrafish development and intestinal function. Genetics 2022; 222:iyac133. [PMID: 36218393 PMCID: PMC9713462 DOI: 10.1093/genetics/iyac133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 07/20/2022] [Indexed: 12/13/2022] Open
Abstract
Transcription factors play important roles in the development of the intestinal epithelium and its ability to respond to endocrine, nutritional, and microbial signals. Hepatocyte nuclear factor 4 family nuclear receptors are liganded transcription factors that are critical for the development and function of multiple digestive organs in vertebrates, including the intestinal epithelium. Zebrafish have 3 hepatocyte nuclear factor 4 homologs, of which, hnf4a was previously shown to mediate intestinal responses to microbiota in zebrafish larvae. To discern the functions of other hepatocyte nuclear factor 4 family members in zebrafish development and intestinal function, we created and characterized mutations in hnf4g and hnf4b. We addressed the possibility of genetic redundancy amongst these factors by creating double and triple mutants which showed different rates of survival, including apparent early lethality in hnf4a; hnf4b double mutants and triple mutants. RNA sequencing performed on digestive tracts from single and double mutant larvae revealed extensive changes in intestinal gene expression in hnf4a mutants that were amplified in hnf4a; hnf4g mutants, but limited in hnf4g mutants. Changes in hnf4a and hnf4a; hnf4g mutants were reminiscent of those seen in mice including decreased expression of genes involved in intestinal function and increased expression of cell proliferation genes, and were validated using transgenic reporters and EdU labeling in the intestinal epithelium. Gnotobiotics combined with RNA sequencing also showed hnf4g has subtler roles than hnf4a in host responses to microbiota. Overall, phenotypic changes in hnf4a single mutants were strongly enhanced in hnf4a; hnf4g double mutants, suggesting a conserved partial genetic redundancy between hnf4a and hnf4g in the vertebrate intestine.
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Affiliation(s)
- Jennifer K Heppert
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Colin R Lickwar
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Matthew C Tillman
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Briana R Davis
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - James M Davison
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hsiu-Yi Lu
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Wei Chen
- Center for Genomics and Computational Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - David L Corcoran
- Center for Genomics and Computational Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - John F Rawls
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
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Transcriptional Integration of Distinct Microbial and Nutritional Signals by the Small Intestinal Epithelium. Cell Mol Gastroenterol Hepatol 2022; 14:465-493. [PMID: 35533983 PMCID: PMC9305020 DOI: 10.1016/j.jcmgh.2022.04.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS The intestine constantly interprets and adapts to complex combinations of dietary and microbial stimuli. However, the transcriptional strategies by which the intestinal epithelium integrates these coincident sources of information remain unresolved. We recently found that microbiota colonization suppresses epithelial activity of hepatocyte nuclear factor 4 nuclear receptor transcription factors, but their integrative regulation was unknown. METHODS We compared adult mice reared germ-free or conventionalized with a microbiota either fed normally or after a single high-fat meal. Preparations of unsorted jejunal intestinal epithelial cells were queried using lipidomics and genome-wide assays for RNA sequencing and ChIP sequencing for the activating histone mark H3K27ac and hepatocyte nuclear factor 4 alpha. RESULTS Analysis of lipid classes, genes, and regulatory regions identified distinct nutritional and microbial responses but also simultaneous influence of both stimuli. H3K27ac sites preferentially increased by high-fat meal in the presence of microbes neighbor lipid anabolism and proliferation genes, were previously identified intestinal stem cell regulatory regions, and were not hepatocyte nuclear factor 4 alpha targets. In contrast, H3K27ac sites preferentially increased by high-fat meal in the absence of microbes neighbor targets of the energy homeostasis regulator peroxisome proliferator activated receptor alpha, neighbored fatty acid oxidation genes, were previously identified enterocyte regulatory regions, and were hepatocyte factor 4 alpha bound. CONCLUSIONS Hepatocyte factor 4 alpha supports a differentiated enterocyte and fatty acid oxidation program in germ-free mice, and that suppression of hepatocyte factor 4 alpha by the combination of microbes and high-fat meal may result in preferential activation of intestinal epithelial cell proliferation programs. This identifies potential transcriptional mechanisms for intestinal adaptation to multiple signals and how microbiota may modulate intestinal lipid absorption, epithelial cell renewal, and systemic energy balance.
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Jawahar J, McCumber AW, Lickwar CR, Amoroso CR, de la Torre Canny SG, Wong S, Morash M, Thierer JH, Farber SA, Bohannan BJM, Guillemin K, Rawls JF. Starvation causes changes in the intestinal transcriptome and microbiome that are reversed upon refeeding. BMC Genomics 2022; 23:225. [PMID: 35317738 PMCID: PMC8941736 DOI: 10.1186/s12864-022-08447-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/07/2022] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The ability of animals and their microbiomes to adapt to starvation and then restore homeostasis after refeeding is fundamental to their continued survival and symbiosis. The intestine is the primary site of nutrient absorption and microbiome interaction, however our understanding of intestinal adaptations to starvation and refeeding remains limited. Here we used RNA sequencing and 16S rRNA gene sequencing to uncover changes in the intestinal transcriptome and microbiome of zebrafish subjected to long-term starvation and refeeding compared to continuously fed controls. RESULTS Starvation over 21 days led to increased diversity and altered composition in the intestinal microbiome compared to fed controls, including relative increases in Vibrio and reductions in Plesiomonas bacteria. Starvation also led to significant alterations in host gene expression in the intestine, with distinct pathways affected at early and late stages of starvation. This included increases in the expression of ribosome biogenesis genes early in starvation, followed by decreased expression of genes involved in antiviral immunity and lipid transport at later stages. These effects of starvation on the host transcriptome and microbiome were almost completely restored within 3 days after refeeding. Comparison with published datasets identified host genes responsive to starvation as well as high-fat feeding or microbiome colonization, and predicted host transcription factors that may be involved in starvation response. CONCLUSIONS Long-term starvation induces progressive changes in microbiome composition and host gene expression in the zebrafish intestine, and these changes are rapidly reversed after refeeding. Our identification of bacterial taxa, host genes and host pathways involved in this response provides a framework for future investigation of the physiological and ecological mechanisms underlying intestinal adaptations to food restriction.
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Affiliation(s)
- Jayanth Jawahar
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Alexander W McCumber
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, 27708, USA
| | - Colin R Lickwar
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Caroline R Amoroso
- Department of Evolutionary Anthropology, Duke University, Durham, NC, 27708, USA
| | - Sol Gomez de la Torre Canny
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Sandi Wong
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Margaret Morash
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | - James H Thierer
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Steven A Farber
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Brendan J M Bohannan
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403, USA
| | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
| | - John F Rawls
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA.
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Chewing the Fat with Microbes: Lipid Crosstalk in the Gut. Nutrients 2022; 14:nu14030573. [PMID: 35276931 PMCID: PMC8840455 DOI: 10.3390/nu14030573] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 01/27/2023] Open
Abstract
It is becoming increasingly important for any project aimed at understanding the effects of diet on human health, to also consider the combined effect of the trillions of microbes within the gut which modify and are modified by dietary nutrients. A healthy microbiome is diverse and contributes to host health, partly via the production and subsequent host absorption of secondary metabolites. Many of the beneficial bacteria in the gut rely on specific nutrients, such as dietary fiber, to survive and thrive. In the absence of those nutrients, the relative proportion of good commensal bacteria dwindles while communities of opportunistic, and potentially pathogenic, bacteria expand. Therefore, it is unsurprising that both diet and the gut microbiome have been associated with numerous human diseases. Inflammatory bowel diseases and colorectal cancer are associated with the presence of certain pathogenic bacteria and risk increases with consumption of a Western diet, which is typically high in fat, protein, and refined carbohydrates, but low in plant-based fibers. Indeed, despite increased screening and better care, colorectal cancer is still the 2nd leading cause of cancer death in the US and is the 3rd most diagnosed cancer among US men and women. Rates are rising worldwide as diets are becoming more westernized, alongside rising rates of metabolic diseases like obesity and diabetes. Understanding how a modern diet influences the microbiota and how subsequent microbial alterations effect human health will become essential in guiding personalized nutrition and healthcare in the future. Herein, we will summarize some of the latest advances in understanding of the three-way interaction between the human host, the gut microbiome, and the specific class of dietary nutrients, lipids.
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Transcriptional programmes underlying cellular identity and microbial responsiveness in the intestinal epithelium. Nat Rev Gastroenterol Hepatol 2021; 18:7-23. [PMID: 33024279 PMCID: PMC7997278 DOI: 10.1038/s41575-020-00357-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/12/2020] [Indexed: 12/19/2022]
Abstract
The intestinal epithelium serves the unique and critical function of harvesting dietary nutrients, while simultaneously acting as a cellular barrier separating tissues from the luminal environment and gut microbial ecosystem. Two salient features of the intestinal epithelium enable it to perform these complex functions. First, cells within the intestinal epithelium achieve a wide range of specialized identities, including different cell types and distinct anterior-posterior patterning along the intestine. Second, intestinal epithelial cells are sensitive and responsive to the dynamic milieu of dietary nutrients, xenobiotics and microorganisms encountered in the intestinal luminal environment. These diverse identities and responsiveness of intestinal epithelial cells are achieved in part through the differential transcription of genes encoded in their shared genome. Here, we review insights from mice and other vertebrate models into the transcriptional regulatory mechanisms underlying intestinal epithelial identity and microbial responsiveness, including DNA methylation, chromatin accessibility, histone modifications and transcription factors. These studies are revealing that most transcription factors involved in intestinal epithelial identity also respond to changes in the microbiota, raising both opportunities and challenges to discern the underlying integrative transcriptional regulatory networks.
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HNF4α is a novel regulator of intestinal glucose-dependent insulinotropic polypeptide. Sci Rep 2019; 9:4200. [PMID: 30862908 PMCID: PMC6414548 DOI: 10.1038/s41598-019-41061-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/23/2019] [Indexed: 11/24/2022] Open
Abstract
Mutations in the HNF4A gene cause MODY1 and are associated with an increased risk of Type 2 diabetes mellitus. On the other hand, incretins are hormones that potentiate reductions in blood glucose levels. Given the established role of incretin-based therapy to treat diabetes and metabolic disorders, we investigated a possible regulatory link between intestinal epithelial HNF4α and glucose-dependent insulinotropic polypeptide (GIP), an incretin that is specifically produced by gut enteroendocrine cells. Conditional deletion of HNF4α in the whole intestinal epithelium was achieved by crossing Villin-Cre and Hnf4αloxP/loxP C57BL/6 mouse models. GIP expression was measured by qPCR, immunofluorescence and ELISA. Gene transcription was assessed by luciferase and electrophoretic mobility shift assays. Metabolic parameters were analyzed by indirect calorimetry and dual-energy X-ray absorptiometry. HNF4α specific deletion in the intestine led to a reduction in GIP. HNF4α was able to positively control Gip transcriptional activity in collaboration with GATA-4 transcription factor. Glucose homeostasis and glucose-stimulated insulin secretion remained unchanged in HNF4α deficient mice. Changes in GIP production in these mice did not impact nutrition or energy metabolism under normal physiology but led to a reduction of bone area and mineral content, a well described physiological consequence of GIP deficiency. Our findings point to a novel regulatory role between intestinal HNF4α and GIP with possible functional impact on bone density.
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Auclair N, Melbouci L, St-Pierre D, Levy E. Gastrointestinal factors regulating lipid droplet formation in the intestine. Exp Cell Res 2018; 363:1-14. [PMID: 29305172 DOI: 10.1016/j.yexcr.2017.12.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/28/2017] [Accepted: 12/29/2017] [Indexed: 12/22/2022]
Abstract
Cytoplasmic lipid droplets (CLD) are considered as neutral lipid reservoirs, which protect cells from lipotoxicity. It became clear that these fascinating dynamic organelles play a role not only in energy storage and metabolism, but also in cellular lipid and protein handling, inter-organelle communication, and signaling among diverse functions. Their dysregulation is associated with multiple disorders, including obesity, liver steatosis and cardiovascular diseases. The central aim of this review is to highlight the link between intra-enterocyte CLD dynamics and the formation of chylomicrons, the main intestinal dietary lipid vehicle, after overviewing the morphology, molecular composition, biogenesis and functions of CLD.
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Affiliation(s)
- N Auclair
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Nutrition, Université de Montréal, Montreal, Quebec, Canada H3T 1C5
| | - L Melbouci
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Department of Sciences and Physical Activities, UQAM, Quebec, Canada H2X 1Y4
| | - D St-Pierre
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Department of Sciences and Physical Activities, UQAM, Quebec, Canada H2X 1Y4
| | - E Levy
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Nutrition, Université de Montréal, Montreal, Quebec, Canada H3T 1C5; Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec, Quebec, Canada G1V 0A6.
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Davison JM, Lickwar CR, Song L, Breton G, Crawford GE, Rawls JF. Microbiota regulate intestinal epithelial gene expression by suppressing the transcription factor Hepatocyte nuclear factor 4 alpha. Genome Res 2017; 27:1195-1206. [PMID: 28385711 PMCID: PMC5495071 DOI: 10.1101/gr.220111.116] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 03/30/2017] [Indexed: 02/07/2023]
Abstract
Microbiota influence diverse aspects of intestinal physiology and disease in part by controlling tissue-specific transcription of host genes. However, host genomic mechanisms mediating microbial control of intestinal gene expression are poorly understood. Hepatocyte nuclear factor 4 (HNF4) is the most ancient family of nuclear receptor transcription factors with important roles in human metabolic and inflammatory bowel diseases, but a role in host response to microbes is unknown. Using an unbiased screening strategy, we found that zebrafish Hnf4a specifically binds and activates a microbiota-suppressed intestinal epithelial transcriptional enhancer. Genetic analysis revealed that zebrafish hnf4a activates nearly half of the genes that are suppressed by microbiota, suggesting microbiota negatively regulate Hnf4a. In support, analysis of genomic architecture in mouse intestinal epithelial cells disclosed that microbiota colonization leads to activation or inactivation of hundreds of enhancers along with drastic genome-wide reduction of HNF4A and HNF4G occupancy. Interspecies meta-analysis suggested interactions between HNF4A and microbiota promote gene expression patterns associated with human inflammatory bowel diseases. These results indicate a critical and conserved role for HNF4A in maintaining intestinal homeostasis in response to microbiota.
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Affiliation(s)
- James M Davison
- Department of Molecular Genetics and Microbiology, Center for the Genomics of Microbial Systems, Duke University, Durham, North Carolina 27710, USA.,Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Colin R Lickwar
- Department of Molecular Genetics and Microbiology, Center for the Genomics of Microbial Systems, Duke University, Durham, North Carolina 27710, USA
| | - Lingyun Song
- Department of Pediatrics, Division of Medical Genetics, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA
| | - Ghislain Breton
- Department of Integrative Biology and Pharmacology, McGovern Medical School, Houston, Texas 77030, USA
| | - Gregory E Crawford
- Department of Pediatrics, Division of Medical Genetics, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA
| | - John F Rawls
- Department of Molecular Genetics and Microbiology, Center for the Genomics of Microbial Systems, Duke University, Durham, North Carolina 27710, USA
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Drouin-Chartier JP, Tremblay AJ, Lemelin V, Lépine MC, Lamarche B, Couture P. Ezetimibe increases intestinal expression of the LDL receptor gene in dyslipidaemic men with insulin resistance. Diabetes Obes Metab 2016; 18:1226-1235. [PMID: 27460541 DOI: 10.1111/dom.12749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/11/2016] [Accepted: 07/21/2016] [Indexed: 01/25/2023]
Abstract
AIM To gain further insight into intestinal cholesterol homeostasis in dyslipidaemic men with insulin resistance (IR) by examining the impact of treatment with ezetimibe on the expression of key genes involved in cholesterol synthesis and LDL receptor (R)-mediated uptake of lipoproteins. METHODS A total of 25 men with dyslipidaemia and IR were recruited to participate in this double-blind, randomized, crossover, placebo-controlled trial. Participants received 10 mg/day ezetimibe or placebo for periods of 12 weeks each. Intestinal gene expression was measured by quantitative PCR in duodenal biopsy samples collected by gastroduodenoscopy at the end of each treatment. RESULTS A total of 20 participants completed the protocol. Treatment with ezetimibe significantly increased intestinal LDLR (+16.2%; P = .01), 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoAR; +14.0%; P = .04) and acetyl-Coenzyme A acetyltransferase 2 (ACAT-2) mRNA expression (+12.5%; P = .03). Changes in sterol regulatory element-binding transcription factor 2 (SREBP-2) expression were significantly correlated with changes in HMG-CoAR (r = 0.55; P < .05), ACAT-2 (r = 0.69; P < .001) and proprotein convertase substilisin/kexin type 9 (PCSK9) expression (r = 0.45; P < .05). CONCLUSIONS These results show that inhibition of intestinal cholesterol absorption by ezetimibe increases expression of the LDLR gene, supporting the concept that increased LDL clearance with ezetimibe treatment occurs not only in the liver but also in the small intestine.
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Affiliation(s)
| | - André J Tremblay
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Valéry Lemelin
- Department of Gastroenterology, CHU de Québec-Université Laval, Quebec City, Canada
| | - Marie-Claude Lépine
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Benoît Lamarche
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Patrick Couture
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
- Department of Medicine, Lipid Research Center, CHU de Québec-Université Laval, Quebec City, Canada
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Tran TTT, Postal BG, Demignot S, Ribeiro A, Osinski C, Pais de Barros JP, Blachnio-Zabielska A, Leturque A, Rousset M, Ferré P, Hajduch E, Carrière V. Short Term Palmitate Supply Impairs Intestinal Insulin Signaling via Ceramide Production. J Biol Chem 2016; 291:16328-38. [PMID: 27255710 DOI: 10.1074/jbc.m115.709626] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Indexed: 12/16/2022] Open
Abstract
The worldwide prevalence of metabolic diseases is increasing, and there are global recommendations to limit consumption of certain nutrients, especially saturated lipids. Insulin resistance, a common trait occurring in obesity and type 2 diabetes, is associated with intestinal lipoprotein overproduction. However, the mechanisms by which the intestine develops insulin resistance in response to lipid overload remain unknown. Here, we show that insulin inhibits triglyceride secretion and intestinal microsomal triglyceride transfer protein expression in vivo in healthy mice force-fed monounsaturated fatty acid-rich olive oil but not in mice force-fed saturated fatty acid-rich palm oil. Moreover, when mouse intestine and human Caco-2/TC7 enterocytes were treated with the saturated fatty acid, palmitic acid, the insulin-signaling pathway was impaired. We show that palmitic acid or palm oil increases ceramide production in intestinal cells and that treatment with a ceramide analogue partially reproduces the effects of palmitic acid on insulin signaling. In Caco-2/TC7 enterocytes, ceramide effects on insulin-dependent AKT phosphorylation are mediated by protein kinase C but not by protein phosphatase 2A. Finally, inhibiting de novo ceramide synthesis improves the response of palmitic acid-treated Caco-2/TC7 enterocytes to insulin. These results demonstrate that a palmitic acid-ceramide pathway accounts for impaired intestinal insulin sensitivity, which occurs within several hours following initial lipid exposure.
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Affiliation(s)
- Thi Thu Trang Tran
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Bárbara Graziela Postal
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Sylvie Demignot
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Agnès Ribeiro
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Céline Osinski
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | | | | | - Armelle Leturque
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Monique Rousset
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Pascal Ferré
- INSERM UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06, Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot, Institute of Cardiometabolism and Nutrition (ICAN), Centre de Recherche des Cordeliers, F-75006 Paris, France
| | - Eric Hajduch
- INSERM UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06, Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot, Institute of Cardiometabolism and Nutrition (ICAN), Centre de Recherche des Cordeliers, F-75006 Paris, France
| | - Véronique Carrière
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France,
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D'Aquila T, Hung YH, Carreiro A, Buhman KK. Recent discoveries on absorption of dietary fat: Presence, synthesis, and metabolism of cytoplasmic lipid droplets within enterocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:730-47. [PMID: 27108063 DOI: 10.1016/j.bbalip.2016.04.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 03/16/2016] [Accepted: 04/16/2016] [Indexed: 02/07/2023]
Abstract
Dietary fat provides essential nutrients, contributes to energy balance, and regulates blood lipid concentrations. These functions are important to health, but can also become dysregulated and contribute to diseases such as obesity, diabetes, cardiovascular disease, and cancer. Within enterocytes, the digestive products of dietary fat are re-synthesized into triacylglycerol, which is either secreted on chylomicrons or stored within cytoplasmic lipid droplets (CLDs). CLDs were originally thought to be inert stores of neutral lipids, but are now recognized as dynamic organelles that function in multiple cellular processes in addition to lipid metabolism. This review will highlight recent discoveries related to dietary fat absorption with an emphasis on the presence, synthesis, and metabolism of CLDs within this process.
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Affiliation(s)
- Theresa D'Aquila
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Alicia Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.
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Baraille F, Ayari S, Carrière V, Osinski C, Garbin K, Blondeau B, Guillemain G, Serradas P, Rousset M, Lacasa M, Cardot P, Ribeiro A. Glucose Tolerance Is Improved in Mice Invalidated for the Nuclear Receptor HNF-4γ: A Critical Role for Enteroendocrine Cell Lineage. Diabetes 2015; 64:2744-56. [PMID: 25829452 DOI: 10.2337/db14-0993] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 03/21/2015] [Indexed: 11/13/2022]
Abstract
Intestine contributes to energy homeostasis through the absorption, metabolism, and transfer of nutrients to the organism. We demonstrated previously that hepatocyte nuclear receptor-4α (HNF-4α) controls intestinal epithelium homeostasis and intestinal absorption of dietary lipids. HNF-4γ, the other HNF-4 form highly expressed in intestine, is much less studied. In HNF-4γ knockout mice, we detect an exaggerated insulin peak and improvement in glucose tolerance during oral but not intraperitoneal glucose tolerance tests, highlighting the involvement of intestine. Moreover, the enteroendocrine L-type cell lineage is modified, as assessed by the increased expression of transcription factors Isl1, Foxa1/2, and Hnf4a, leading to an increase of both GLP-1-positive cell number and basal and stimulated GLP-1 plasma levels potentiating the glucose-stimulated insulin secretion. Using the GLP-1 antagonist exendin (9-39), we demonstrate a direct effect of GLP-1 on improved glucose tolerance. GLP-1 exerts a trophic effect on pancreatic β-cells, and we report an increase of the β-cell fraction correlated with an augmented number of proliferative islet cells and with resistance to streptozotocin-induced diabetes. In conclusion, the loss of HNF-4γ improves glucose homeostasis through a modulation of the enteroendocrine cell lineage.
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Affiliation(s)
- Floriane Baraille
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Sami Ayari
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Véronique Carrière
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Céline Osinski
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Kevin Garbin
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
| | - Bertrand Blondeau
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Ghislaine Guillemain
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Patricia Serradas
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Monique Rousset
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Michel Lacasa
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
| | - Philippe Cardot
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Agnès Ribeiro
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
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14
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Yao HS, Wang J, Zhang XP, Wang LZ, Wang Y, Li XX, Jin KZ, Hu ZQ, Wang WJ. Hepatocyte nuclear factor 4α suppresses the aggravation of colon carcinoma. Mol Carcinog 2015; 55:458-72. [PMID: 25808746 DOI: 10.1002/mc.22294] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 12/19/2014] [Accepted: 01/14/2015] [Indexed: 01/21/2023]
Affiliation(s)
- Hou Shan Yao
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Juan Wang
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Xiao Ping Zhang
- Medical Intervention Engineering; Tongji University; North Zhongshan Road; Shanghai China
| | - Liang Zhe Wang
- Department of pathology; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Yi Wang
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Xin Xing Li
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Kai Zhou Jin
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Zhi Qian Hu
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
| | - Wei Jun Wang
- Department of General Surgery; Shanghai Chang Zheng Hospital; Second Military Medical University; 415 Feng Yang Road; Shanghai China
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Abstract
The nuclear receptor superfamily includes many receptors, identified based on their similarity to steroid hormone receptors but without a known ligand. The study of how these receptors are diversely regulated to interact with genomic regions to control a plethora of biological processes has provided critical insight into development, physiology, and the molecular pathology of disease. Here we provide a compendium of these so-called orphan receptors and focus on what has been learned about their modes of action, physiological functions, and therapeutic promise.
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Affiliation(s)
- Shannon E Mullican
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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16
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Khaldoun SA, Emond-Boisjoly MA, Chateau D, Carrière V, Lacasa M, Rousset M, Demignot S, Morel E. Autophagosomes contribute to intracellular lipid distribution in enterocytes. Mol Biol Cell 2013; 25:118-32. [PMID: 24173715 PMCID: PMC3873883 DOI: 10.1091/mbc.e13-06-0324] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Delivery of alimentary lipids induces immediate autophagic response in enterocytes. Forming autophagosomes are recruited to the ER membrane, where they capture nascent lipid droplets and later fuse with lysosomes, illustrating for the first time the role of autophagy in neutral-lipid distribution in enterocytes. Enterocytes, the intestinal absorptive cells, have to deal with massive alimentary lipids upon food consumption. They orchestrate complex lipid-trafficking events that lead to the secretion of triglyceride-rich lipoproteins and/or the intracellular transient storage of lipids as lipid droplets (LDs). LDs originate from the endoplasmic reticulum (ER) membrane and are mainly composed of a triglyceride (TG) and cholesterol-ester core surrounded by a phospholipid and cholesterol monolayer and specific coat proteins. The pivotal role of LDs in cellular lipid homeostasis is clearly established, but processes regulating LD dynamics in enterocytes are poorly understood. Here we show that delivery of alimentary lipid micelles to polarized human enterocytes induces an immediate autophagic response, accompanied by phosphatidylinositol-3-phosphate appearance at the ER membrane. We observe a specific and rapid capture of newly synthesized LD at the ER membrane by nascent autophagosomal structures. By combining pharmacological and genetic approaches, we demonstrate that autophagy is a key player in TG targeting to lysosomes. Our results highlight the yet-unraveled role of autophagy in the regulation of TG distribution, trafficking, and turnover in human enterocytes.
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Affiliation(s)
- Salem Ait Khaldoun
- Centre de Recherche des Cordeliers, UMR S 872, Université Pierre et Marie Curie-Paris 6, Institut National de la Santé et de la Recherche Médicale, U 872 and UMR S 872, Université Paris Descartes-Paris 5, F-75006 Paris, France Laboratoire de Pharmacologie Cellulaire et Moléculaire, Ecole Pratique des Hautes Etudes, F-75006 Paris, France
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Buttet M, Traynard V, Tran TTT, Besnard P, Poirier H, Niot I. From fatty-acid sensing to chylomicron synthesis: role of intestinal lipid-binding proteins. Biochimie 2013; 96:37-47. [PMID: 23958439 DOI: 10.1016/j.biochi.2013.08.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 08/05/2013] [Indexed: 12/31/2022]
Abstract
Today, it is well established that the development of obesity and associated diseases results, in part, from excessive lipid intake associated with a qualitative imbalance. Among the organs involved in lipid homeostasis, the small intestine is the least studied even though it determines lipid bioavailability and largely contributes to the regulation of postprandial hyperlipemia (triacylglycerols (TG) and free fatty acids (FFA)). Several Lipid-Binding Proteins (LBP) are expressed in the small intestine. Their supposed intestinal functions were initially based on what was reported in other tissues, and took no account of the physiological specificity of the small intestine. Progressively, the identification of regulating factors of intestinal LBP and the description of the phenotype of their deletion have provided new insights into cellular and molecular mechanisms involved in fat absorption. This review will discuss the physiological contribution of each LBP in the main steps of intestinal absorption of long-chain fatty acids (LCFA): uptake, trafficking and reassembly into chylomicrons (CM). Moreover, current data indicate that the small intestine is able to adapt its lipid absorption capacity to the fat content of the diet, especially through the coordinated induction of LBP. This adaptation requires the existence of a mechanism of intestinal lipid sensing. Emerging data suggest that the membrane LBP CD36 may operate as a lipid receptor that triggers an intracellular signal leading to the modulation of the expression of LBP involved in CM formation. This event could be the starting point for the optimized synthesis of large CM, which are efficiently degraded in blood. Better understanding of this intestinal lipid sensing might provide new approaches to decrease the prevalence of postprandial hypertriglyceridemia, which is associated with cardiovascular diseases, insulin resistance and obesity.
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Affiliation(s)
- Marjorie Buttet
- Physiologie de la Nutrition et Toxicologie Team (NUTox), UMR U866 INSERM, Université de Bourgogne, AgroSup Dijon, 1 Esplanade Erasme, 21000 Dijon, France
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18
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Pang G, Xie J, Chen Q, Hu Z. How functional foods play critical roles in human health. FOOD SCIENCE AND HUMAN WELLNESS 2012. [DOI: 10.1016/j.fshw.2012.10.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
Hepatocyte nuclear 4 alpha (HNF4α), involved in glucose and lipid metabolism, has been linked to intestinal inflammation and abnormal mucosal permeability. Moreover, in a genome-wide association study, the HNF4A locus has been associated with ulcerative colitis. The objective of our study was to evaluate the association between HNF4α genetic variants and Crohn's disease (CD) in two distinct Canadian pediatric cohorts. The sequencing of the HNF4A gene in 40 French Canadian patients led to the identification of 27 single nucleotide polymorphism (SNP)s with a minor allele frequency >5%. To assess the impact of these SNPs on disease susceptibility, we first conducted a case-control discovery study on 358 subjects with CD and 542 controls. We then carried out a replication study in a separate cohort of 416 cases and 1208 controls. In the discovery cohort, the genotyping of the identified SNPs revealed that six were significantly associated with CD. Among them, rs1884613 was replicated in the second CD cohort (odds ratio (OR): 1.33; P<0.012) and this association remained significant when both cohorts were combined and after correction for multiple testing (OR: 1.39; P<0.004). An 8-marker P2 promoter haplotype containing rs1884613 was also found associated with CD (P<2.09 × 10(-4) for combined cohorts). This is the first report showing that the HNF4A locus may be a common genetic determinant of childhood-onset CD. These findings highlight the importance of the intestinal epithelium and oxidative protection in the pathogenesis of CD.
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