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Luiskari L, Launonen H, Lindén J, Lehto M, Vapaatalo H, Salmenkari H, Korpela R. Ketogenic Diet High in Saturated Fat Promotes Colonic Claudin Expression without Changes in Intestinal Permeability to Iohexol in Healthy Mice. Nutrients 2023; 16:18. [PMID: 38201850 PMCID: PMC10780785 DOI: 10.3390/nu16010018] [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: 10/10/2023] [Revised: 12/11/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
Ketogenic diets (KDs) have been studied in preclinical models of intestinal diseases. However, little is known of how the fat source of these diets influences the intestinal barrier. Herein, we studied the impact of four-week feeding with KD high either in saturated fatty acids (SFA-KD) or polyunsaturated linoleic acid (LA-KD) on paracellular permeability of the intestine to iohexol in healthy male C57BL/6J mice. We investigated jejunal and colonic tight junction protein expression, histological changes, and inflammatory markers (Il1b, Il6, Tnf, and Lcn2), as well as the activity and expression of intestinal alkaline phosphatase (IAP) in feces and jejunal tissue, respectively, and plasma lipopolysaccharide. KDs did not change intestinal permeability to iohexol after two or twenty-six days of feeding regardless of fat quality. SFA-KD, but not LA-KD, upregulated the colonic expression of tight junction proteins claudin-1 and -4, as well as the activity of IAP. Both KDs resulted in increased epithelial vacuolation in jejunum, and this was pronounced in SFA-KD. Jejunal Il1β expression was lower and colonic Il6 expression higher in LA-KD compared to SFA-KD. In colon, Tnf mRNA was increased in LA-KD when compared to controls. Overall, the results suggest that KDs do not influence intestinal permeability to iohexol but elicit changes in colonic tight junction proteins and inflammatory markers in both jejunum and colon. Future research will show whether these changes become of importance upon proinflammatory insults.
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Affiliation(s)
- Lotta Luiskari
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland; (H.L.); (H.V.)
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Hanna Launonen
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland; (H.L.); (H.V.)
| | - Jere Lindén
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, 00014 Helsinki, Finland;
- Finnish Centre for Laboratory Animal Pathology, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Markku Lehto
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00290 Helsinki, Finland; (M.L.); (H.S.)
- Department of Nephrology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Heikki Vapaatalo
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland; (H.L.); (H.V.)
| | - Hanne Salmenkari
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00290 Helsinki, Finland; (M.L.); (H.S.)
- Department of Nephrology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Riitta Korpela
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland; (H.L.); (H.V.)
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
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Syed-Abdul MM, Stahel P, Zembroski A, Tian L, Xiao C, Nahmias A, Bookman I, Buhman KK, Lewis GF. Glucagon-like peptide-2 acutely enhances chylomicron secretion in humans without mobilizing cytoplasmic lipid droplets. J Clin Endocrinol Metab 2022; 108:1084-1092. [PMID: 36458872 DOI: 10.1210/clinem/dgac690] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022]
Abstract
CONTEXT A portion of ingested fats are retained in the intestine for many hours before they are mobilized and secreted in chylomicron (CM) particles. Factors like glucagon-like peptide-2 (GLP-2) and glucose can mobilize these stored intestinal lipids and enhance CM secretion. We have recently demonstrated in rodents that GLP-2 acutely enhances CM secretion by mechanisms that do not involve the canonical CM synthetic assembly and secretory pathways. OBJECTIVE To further investigate the mechanism of GLP-2's potent intestinal lipid mobilizing effect, we examined intracellular cytoplasmic lipid droplets (CLDs) in intestinal biopsies of humans administered GLP-2 or placebo. DESIGN, SETTING, PATIENTS, AND INTERVENTIONS A single dose of placebo or GLP-2 was administered subcutaneously five hours after ingesting a high-fat bolus. In one subset of participants, plasma samples were collected to quantify lipid and lipoprotein concentrations for 3 hours post-placebo or GLP-2. In another subset, a duodenal biopsy was obtained one-hour post-placebo or GLP-2 administration for transmission electron microscopy (TEM) and proteomic analysis. RESULTS GLP-2 significantly increased plasma-TG by 46% (P = 0.009), mainly in CM-sized particles (CM-TG) by 133% (P = 0.003), without reducing duodenal CLD size or number. Several proteins of interest were identified that require further investigation to elucidate their potential role in GLP-2-mediated CM secretion. CONCLUSIONS Unlike glucose that mobilizes enterocyte CLDs and enhances CM secretion, GLP-2 acutely increased plasma CMs without significant mobilization of CLDs, supporting our previous findings that GLP-2 does not act directly on enterocytes to enhance CM secretion and most likely mobilizes secreted CMs in the lamina propria and lymphatics.
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Affiliation(s)
- Majid Mufaqam Syed-Abdul
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, CANADA
| | - Priska Stahel
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, CANADA
| | - Alyssa Zembroski
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, USA
| | - Lili Tian
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, CANADA
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, CANADA
| | - Avital Nahmias
- Maccabi Healthcare Services, Endocrinology Division, Tel Aviv, Israel
| | - Ian Bookman
- Kensington Screening Clinic, Department of Medicine, University of Toronto, Toronto, Ontario, CANADA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, USA
| | - Gary F Lewis
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, CANADA
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Tian L, Syed-Abdul MM, Stahel P, Lewis GF. Enteral glucose, absorbed and metabolized, potently enhances mesenteric lymph flow in chow- and high-fat-fed rats. Am J Physiol Gastrointest Liver Physiol 2022; 323:G331-G340. [PMID: 35916412 DOI: 10.1152/ajpgi.00095.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A portion of absorbed dietary triglycerides (TG) is retained in the intestine after the postprandial period, within intracellular and extracellular compartments. This pool of TG can be mobilized in response to several stimuli, including oral glucose. The objective of this study was to determine whether oral glucose must be absorbed and metabolized to mobilize TG in rats and whether high-fat feeding, a model of insulin resistance, alters the lipid mobilization response to glucose. Lymph flow, TG concentration, TG output, and apolipoprotein B48 (apoB48) concentration and output were assessed after an intraduodenal lipid bolus in rats exposed to the following intraduodenal administrations 5 h later: saline (placebo), glucose, 2-deoxyglucose (2-DG, absorbed but not metabolized), or glucose + phlorizin (intestinal glucose absorption inhibitor). Glucose alone, but not 2-DG or glucose + phlorizin treatments, stimulated lymph flow, TG output, and apoB48 output compared with placebo. The effects of glucose in high-fat-fed rats were similar to those in chow-fed rats. In conclusion, glucose must be both absorbed and metabolized to enhance lymph flow and intestinal lipid mobilization. This effect is qualitatively and quantitatively similar in high-fat- and chow-fed rats. The precise signaling mechanism whereby enteral glucose enhances lymph flow and mobilizes enteral lipid remains to be determined.NEW & NOTEWORTHY Glucose potently enhances mesenteric lymph flow in chow- and high-fat-fed rats. The magnitude of glucose effect on lymph flow is no different in chow- and high-fat-fed rats. Glucose must be absorbed and metabolized to enhance lymph flow and mobilize intestinal lipid.
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Affiliation(s)
- Lili Tian
- Division of Endocrinology, Department of Medicine and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Majid Mufaqam Syed-Abdul
- Division of Endocrinology, Department of Medicine and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Priska Stahel
- Division of Endocrinology, Department of Medicine and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Gary F Lewis
- Division of Endocrinology, Department of Medicine and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Cook JR, Kohan AB, Haeusler RA. An Updated Perspective on the Dual-Track Model of Enterocyte Fat Metabolism. J Lipid Res 2022; 63:100278. [PMID: 36100090 PMCID: PMC9593242 DOI: 10.1016/j.jlr.2022.100278] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/08/2022] [Accepted: 08/31/2022] [Indexed: 02/04/2023] Open
Abstract
The small intestinal epithelium has classically been envisioned as a conduit for nutrient absorption, but appreciation is growing for a larger and more dynamic role for enterocytes in lipid metabolism. Considerable gaps remain in our knowledge of this physiology, but it appears that the enterocyte's structural polarization dictates its behavior in fat partitioning, treating fat differently based on its absorption across the apical versus the basolateral membrane. In this review, we synthesize existing data and thought on this dual-track model of enterocyte fat metabolism through the lens of human integrative physiology. The apical track includes the canonical pathway of dietary lipid absorption across the apical brush-border membrane, leading to packaging and secretion of those lipids as chylomicrons. However, this track also reserves a portion of dietary lipid within cytoplasmic lipid droplets for later uses, including the "second-meal effect," which remains poorly understood. At the same time, the enterocyte takes up circulating fats across the basolateral membrane by mechanisms that may include receptor-mediated import of triglyceride-rich lipoproteins or their remnants, local hydrolysis and internalization of free fatty acids, or enterocyte de novo lipogenesis using basolaterally absorbed substrates. The ultimate destinations of basolateral-track fat may include fatty acid oxidation, structural lipid synthesis, storage in cytoplasmic lipid droplets, or ultimate resecretion, although the regulation and purposes of this basolateral track remain mysterious. We propose that the enterocyte integrates lipid flux along both of these tracks in order to calibrate its overall program of lipid metabolism.
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Affiliation(s)
- Joshua R. Cook
- Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA,Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Alison B. Kohan
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rebecca A. Haeusler
- Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA,Department of Pathology and Cell Biology; Columbia University College of Physicians and Surgeons, New York, NY, USA,For correspondence: Rebecca A. Haeusler
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Adaptation to short-term extreme fat consumption alters intestinal lipid handling in male and female mice. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159208. [PMID: 35926775 DOI: 10.1016/j.bbalip.2022.159208] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/07/2022] [Accepted: 07/18/2022] [Indexed: 11/21/2022]
Abstract
The small intestine is a highly adaptable organ serving as both a barrier to the external environment and a conduit for nutrient absorption. Enterocytes package dietary triglycerides (TG) into chylomicrons for transport into circulation; the remaining TGs are stored in cytosolic lipid droplets (CLDs). The current study aimed to characterize the impact of diet composition on intestinal lipid handling in male and female wild-type mice. Mice were continued on their grain-based diet (GBD) and switched to a high-fat, high cholesterol Western-style diet (WD) or a ketogenic diet (KD) for 3 or 5 weeks. KD-fed mice displayed significantly higher plasma TG levels in response to an olive oil gavage than WD- and GBD-fed mice; TG levels were ~2-fold higher in male KD-fed mice than female KD-fed mice. Poloxamer-407 experiments revealed enhanced intestinal-TG secretion rates in male mice fed a KD upon olive oil gavage, whereas secretion rates were unchanged in female mice. Surprisingly, jejunal CLD size and TG mass after oil gavage were similar among the groups. At fasting, TG mass was significantly higher in the jejunum of male KD-fed mice and the duodenum of female KD-fed mice, providing increased substrate for chylomicron formation. In addition to greater fasting intestinal TG stores, KD-fed male mice displayed longer small intestinal lengths, while female mice displayed markedly longer jejunal villi lengths. After 5 week of diet, 12 h fasting-2 h refeeding experiments revealed jejunal TG levels were similar between diet groups in male mice; however, in female mice, jejunal TG mass was significantly higher in KD-fed mice compared to GBD- and WD-fed mice. These experiments reveal that KD feeding promotes distinct morphological and functional changes to the small intestine compared to the WD diet. Moreover, changes to intestinal lipid handling in response to carbohydrate and protein restriction manifest differently in male and female mice.
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Ghanem M, Lewis GF, Xiao C. Recent advances in cytoplasmic lipid droplet metabolism in intestinal enterocyte. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159197. [PMID: 35820577 DOI: 10.1016/j.bbalip.2022.159197] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/03/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
Processing of dietary fats in the intestine is a highly regulated process that influences whole-body energy homeostasis and multiple physiological functions. Dysregulated lipid handling in the intestine leads to dyslipidemia and atherosclerotic cardiovascular disease. In intestinal enterocytes, lipids are incorporated into lipoproteins and cytoplasmic lipid droplets (CLDs). Lipoprotein synthesis and CLD metabolism are inter-connected pathways with multiple points of regulation. This review aims to highlight recent advances in the regulatory mechanisms of lipid processing in the enterocyte, with particular focus on CLDs. In-depth understanding of the regulation of lipid metabolism in the enterocyte may help identify therapeutic targets for the treatment and prevention of metabolic disorders.
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Affiliation(s)
- Murooj Ghanem
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology, University of Toronto, and University Health Network, Toronto, ON, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
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Guerbette T, Boudry G, Lan A. Mitochondrial function in intestinal epithelium homeostasis and modulation in diet-induced obesity. Mol Metab 2022; 63:101546. [PMID: 35817394 PMCID: PMC9305624 DOI: 10.1016/j.molmet.2022.101546] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/27/2022] [Accepted: 07/06/2022] [Indexed: 11/30/2022] Open
Abstract
Background Systemic low-grade inflammation observed in diet-induced obesity has been associated with dysbiosis and disturbance of intestinal homeostasis. This latter relies on an efficient epithelial barrier and coordinated intestinal epithelial cell (IEC) renewal that are supported by their mitochondrial function. However, IEC mitochondrial function might be impaired by high fat diet (HFD) consumption, notably through gut-derived metabolite production and fatty acids, that may act as metabolic perturbators of IEC. Scope of review This review presents the current general knowledge on mitochondria, before focusing on IEC mitochondrial function and its role in the control of intestinal homeostasis, and featuring the known effects of nutrients and metabolites, originating from the diet or gut bacterial metabolism, on IEC mitochondrial function. It then summarizes the impact of HFD on mitochondrial function in IEC of both small intestine and colon and discusses the possible link between mitochondrial dysfunction and altered intestinal homeostasis in diet-induced obesity. Major conclusions HFD consumption provokes a metabolic shift toward fatty acid β-oxidation in the small intestine epithelial cells and impairs colonocyte mitochondrial function, possibly through downstream consequences of excessive fatty acid β-oxidation and/or the presence of deleterious metabolites produced by the gut microbiota. Decreased levels of ATP and concomitant O2 leaks into the intestinal lumen could explain the alterations of intestinal epithelium dynamics, barrier disruption and dysbiosis that contribute to the loss of epithelial homeostasis in diet-induced obesity. However, the effect of HFD on IEC mitochondrial function in the small intestine remains unknown and the precise mechanisms by which HFD induces mitochondrial dysfunction in the colon have not been elucidated so far.
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Affiliation(s)
| | - Gaëlle Boudry
- Institut Numecan, INSERM, INRAE, Univ Rennes, Rennes, France.
| | - Annaïg Lan
- Institut Numecan, INSERM, INRAE, Univ Rennes, Rennes, France; Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
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8
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Grande EM, Raka F, Hoffman S, Adeli K. GLP-2 Regulation of Dietary Fat Absorption and Intestinal Chylomicron Production via Neuronal Nitric Oxide Synthase (nNOS) Signaling. Diabetes 2022; 71:1388-1399. [PMID: 35476805 DOI: 10.2337/db21-1053] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/17/2022] [Indexed: 11/13/2022]
Abstract
Postprandial dyslipidemia is a metabolic condition commonly associated with insulin-resistant states, such as obesity and type 2 diabetes. It is characterized by the overproduction of intestinal chylomicron particles and excess atherogenic chylomicron remnants in circulation. We have previously shown that glucagon-like peptide 2 (GLP-2) augments dietary fat uptake and chylomicron production in insulin-resistant states; however, the underlying mechanisms remain unclear. Previous studies have implicated nitric oxide (NO) in the absorptive actions of GLP-2. In this study, we report a novel role for neuronal NO synthase (nNOS)-mediated NO generation in lipid uptake and chylomicron formation based on studies in C57BL/6J mice, nNOS-/- mice, and Syrian golden hamsters after intraduodenal and oral fat administration. GLP-2 treatment in wild-type (WT) mice significantly increased postprandial lipid accumulation and circulating apolipoprotein B48 protein levels, while these effects were abolished in nNOS-/- mice. nNOS inhibition in Syrian golden hamsters and protein kinase G (PKG) inhibition in WT mice also abrogated the effect of GLP-2 on postprandial lipid accumulation. These studies demonstrate a novel mechanism in which nNOS-generated NO is crucial for GLP-2-mediated lipid absorption and chylomicron production in both mouse and hamster models. Overall, our data implicate an nNOS-PKG-mediated pathway in GLP-2-mediated stimulation of dietary fat absorption and intestinal chylomicron production.
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Affiliation(s)
- Elisabeth M Grande
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Fitore Raka
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Simon Hoffman
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Khosrow Adeli
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Abstract
PURPOSE OF REVIEW Lymphatics are known to have active, regulated pumping by smooth muscle cells that enhance lymph flow, but whether active regulation of lymphatic pumping contributes significantly to the rate of appearance of chylomicrons (CMs) in the blood circulation (i.e., CM production rate) is not currently known. In this review, we highlight some of the potential mechanisms by which lymphatics may regulate CM production. RECENT FINDINGS Recent data from our lab and others are beginning to provide clues that suggest a more active role of lymphatics in regulating CM appearance in the circulation through various mechanisms. Potential contributors include apolipoproteins, glucose, glucagon-like peptide-2, and vascular endothelial growth factor-C, but there are likely to be many more. SUMMARY The digested products of dietary fats absorbed by the small intestine are re-esterified and packaged by enterocytes into large, triglyceride-rich CM particles or stored temporarily in intracellular cytoplasmic lipid droplets. Secreted CMs traverse the lamina propria and are transported via lymphatics and then the blood circulation to liver and extrahepatic tissues, where they are stored or metabolized as a rich energy source. Although indirect data suggest a relationship between lymphatic pumping and CM production, this concept requires more experimental evidence before we can be sure that lymphatic pumping contributes significantly to the rate of CM appearance in the blood circulation.
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Affiliation(s)
- Majid M Syed-Abdul
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Lili Tian
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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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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Wit M, Trujillo-Viera J, Strohmeyer A, Klingenspor M, Hankir M, Sumara G. When fat meets the gut-focus on intestinal lipid handling in metabolic health and disease. EMBO Mol Med 2022; 14:e14742. [PMID: 35437952 PMCID: PMC9081902 DOI: 10.15252/emmm.202114742] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
The regular overconsumption of energy‐dense foods (rich in lipids and sugars) results in elevated intestinal nutrient absorption and consequently excessive accumulation of lipids in the liver, adipose tissue, skeletal muscles, and other organs. This can eventually lead to obesity and obesity‐associated diseases such as type 2 diabetes (T2D), non‐alcoholic fatty liver disease (NAFLD), cardiovascular disease, and certain types of cancer, as well as aggravate inflammatory bowel disease (IBD). Therefore, targeting the pathways that regulate intestinal nutrient absorption holds significant therapeutic potential. In this review, we discuss the molecular and cellular mechanisms controlling intestinal lipid handling, their relevance to the development of metabolic diseases, and emerging therapeutic strategies.
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Affiliation(s)
- Magdalena Wit
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
| | - Jonathan Trujillo-Viera
- Rudolf-Virchow-Zentrum, Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Akim Strohmeyer
- Chair for Molecular Nutritional Medicine, Technical University of Munich, TUM School of Life Sciences Weihenstephan, Freising, Germany.,EKFZ - Else Kröner-Fresenius-Center for Nutritional Medicine, Technical University of Munich, Munich, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Martin Klingenspor
- Chair for Molecular Nutritional Medicine, Technical University of Munich, TUM School of Life Sciences Weihenstephan, Freising, Germany.,EKFZ - Else Kröner-Fresenius-Center for Nutritional Medicine, Technical University of Munich, Munich, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Mohammed Hankir
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Grzegorz Sumara
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
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Enterocyte-specific ATGL overexpression affects intestinal and systemic cholesterol homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159121. [PMID: 35150895 DOI: 10.1016/j.bbalip.2022.159121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/19/2022] [Accepted: 02/01/2022] [Indexed: 11/24/2022]
Abstract
Enterocytes of the small intestine (SI) play an important role in maintaining systemic lipid levels by regulating dietary lipid absorption and postprandial lipoprotein secretion. An excessive amount of dietary-derived triglycerides (TGs) taken up by the apical side of enterocytes or basolaterally internalized lipoprotein remnants can be transiently stored in cytosolic lipid droplets (cLDs). As mice lacking adipose TG lipase (ATGL) in the SI display massive accumulation of cLDs but also delayed cholesterol absorption, we hypothesized that SI-specific overexpression of ATGL (Atgl iTg) might have beneficial effects on lipid homeostasis in the gut and possibly throughout the body. Here, we demonstrate that Atgl iTg mice had only modestly increased enzymatic activity despite drastically elevated Atgl mRNA levels (up to 120-fold) on chow diet, and was highly induced upon high-fat/high-cholesterol diet (HF/HCD) feeding. Atgl iTg mice showed markedly reduced intestinal TG concentrations after acute and chronic lipid challenge without affecting chylomicron TG secretion. Circulating plasma cholesterol levels were significantly lower in Atgl iTg mice under different feeding conditions, contrasting the accelerated uptake of dietary cholesterol into the circulation after HF/HCD feeding. In the fasted state, gene expression analysis revealed modulation of PPARα and liver X receptor (LXR) target genes by an increased fatty acid release, whereas the decreased plasma cholesterol concentrations in refed mice were more likely due to changes in HDL synthesis and secretion. We conclude that ATGL, in addition to its role in TG catabolism, plays a critical role in whole-body cholesterol homeostasis by modulating PPARα and LXR signaling in intestinal enterocytes.
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Morrow NM, Trzaskalski NA, Hanson AA, Fadzeyeva E, Telford DE, Chhoker SS, Sutherland BG, Edwards JY, Huff MW, Mulvihill EE. Nobiletin Prevents High-Fat Diet-Induced Dysregulation of Intestinal Lipid Metabolism and Attenuates Postprandial Lipemia. Arterioscler Thromb Vasc Biol 2022; 42:127-144. [PMID: 34911361 DOI: 10.1161/atvbaha.121.316896] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Nobiletin is a dietary flavonoid that improves insulin resistance and atherosclerosis in mice with metabolic dysfunction. Dysregulation of intestinal lipoprotein metabolism contributes to atherogenesis. The objective of the study was to determine if nobiletin targets the intestine to improve metabolic dysregulation in both male and female mice. Approach and Results: Triglyceride-rich lipoprotein (TRL) secretion, intracellular triglyceride kinetics, and intestinal morphology were determined in male and female LDL (low-density lipoprotein) receptor knockout (Ldlr-/-), and male wild-type mice fed a standard laboratory diet or high-fat, high-cholesterol (HFHC) diet ± nobiletin using an olive oil gavage, radiotracers, and electron microscopy. Nobiletin attenuated postprandial TRL levels in plasma and enhanced TRL clearance. Nobiletin reduced fasting jejunal triglyceride accumulation through accelerated TRL secretion and lower jejunal fatty acid synthesis with no impact on fatty acid oxidation. Fasting-refeeding experiments revealed that nobiletin led to higher levels of phosphorylated AKT (protein kinase B) and FoxO1 (forkhead box O1) and normal Srebf1c expression indicating increased insulin sensitivity. Intestinal length and weight were diminished by HFHC feeding and restored by nobiletin. Both fasting and postprandial plasma GLP-1 (glucagon-like peptide-1; and likely GLP-2) were elevated in response to nobiletin. Treatment with a GLP-2 receptor antagonist, GLP-2(3-33), reduced villus length in HFHC-fed mice but did not impact TRL secretion in any diet group. In contrast to males, nobiletin did not improve postprandial lipid parameters in female mice. CONCLUSIONS Nobiletin opposed the effects of the HFHC diet by normalizing intestinal de novo lipogenesis through improved insulin sensitivity. Nobiletin prevents postprandial lipemia because the enhanced TRL clearance more than compensates for increased TRL secretion.
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Affiliation(s)
- Nadya M Morrow
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Biochemistry (N.M.M., S.S.C., M.W.H.), The University of Western Ontario, London, Canada
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Natasha A Trzaskalski
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Antonio A Hanson
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Evgenia Fadzeyeva
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Dawn E Telford
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Medicine (D.E.T., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Sanjiv S Chhoker
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Biochemistry (N.M.M., S.S.C., M.W.H.), The University of Western Ontario, London, Canada
| | - Brian G Sutherland
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Jane Y Edwards
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Medicine (D.E.T., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Murray W Huff
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Biochemistry (N.M.M., S.S.C., M.W.H.), The University of Western Ontario, London, Canada
- Department of Medicine (D.E.T., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Erin E Mulvihill
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Centre for Infection, Immunity and Inflammation, Ottawa, Ontario, Canada (E.E.M)
- Montreal Diabetes Research Group, Montreal, Quebec, Canada (E.E.M)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
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14
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Zhu Q, Yang Q, Shen L, Qu J, Xu M, Wang DQH, Tso P, Liu M. Impact of Sequential Lipid Meals on Lymphatic Lipid Absorption and Transport in Rats. Genes (Basel) 2022; 13:277. [PMID: 35205322 PMCID: PMC8871868 DOI: 10.3390/genes13020277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 01/05/2023] Open
Abstract
The sequential meal pattern has recently received more attention because it reflects a phycological diet style for human beings. The present study investigated the effects of the second lipid meal on lymphatic lipid absorption and transport in adult rats following a previous lipid meal. Using the well-established lymph fistula model, we found that the second lipid meal significantly increased the lymphatic output of triglycerides, cholesterol, phospholipids, and non-esterified fatty acids compared with a single lipid meal. Besides that, the time reaching the peak of each lipid output was significantly faster compared with the first lipid meal. Additionally, the second lipid meal significantly increased the lymphatic output of apolipoprotein A-IV (ApoA-IV), but not apolipoprotein B-48 (ApoB-48) or apolipoprotein A-I (ApoA-I). Interestingly, the triglyceride/apoB-48 ratio was significantly increased after the second lipid meal, indicating the increased chylomicron size in the lymph. Finally, the second lipid meal increased the lymphatic output of rat mucosal mast cell protease II (RMCPII). No change was found in the expression of genes related to the permeability of lymphatic lacteals, including vascular endothelial growth factor-A (Vegfa), vascular endothelial growth factor receptor 1 (Flt1), and Neuropilin1 (Nrp1). Collectively, the second lipid meal led to the rapid appearance of bigger-sized chylomicrons in the lymph. It also increased the lymphatic output of various lipids and apoA-IV, and mucosal mast cell activity in the intestine.
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Affiliation(s)
- Qi Zhu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
| | - Qing Yang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
| | - Ling Shen
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
| | - Jie Qu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
| | - Meifeng Xu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
| | - David Q.-H. Wang
- Department of Medicine and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (Q.Z.); (Q.Y.); (L.S.); (J.Q.); (M.X.); (P.T.)
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15
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Acevedo-Fani A, Singh H. Biophysical insights into modulating lipid digestion in food emulsions. Prog Lipid Res 2021; 85:101129. [PMID: 34710489 DOI: 10.1016/j.plipres.2021.101129] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/14/2021] [Accepted: 10/21/2021] [Indexed: 10/20/2022]
Abstract
During the last decade, major scientific advances on understanding the mechanisms of lipid digestion and metabolism have been made, with a view to addressing health issues (such as obesity) associated with overconsumption of lipid-rich and sucrose-rich foods. As lipids in common foods exist in the form of emulsions, the structuring of emulsions has been one the main strategies for controlling the rate of lipid digestion and absorption, at least from a colloid science viewpoint. Modulating the kinetics of lipid digestion and absorption offers interesting possibilities for developing foods that can provide control of postprandial lipaemia and control the release of lipophilic compounds. Food emulsions can be designed to achieve considerable differences in the kinetics of lipid digestion but most research has been applied to relatively simple model systems and in in vitro digestion models. Further research to translate this knowledge into more complex food systems and to validate the results in human studies is required. One promising approach to delay/control lipid digestion is to alter the stomach emptying rate of lipids, which is largely affected by interactions of emulsion droplets with the food matrices. Food matrices with different responses to the gastric environment and with different interactions between oil droplets and the food matrix can be designed to influence lipid digestion. This review focuses on key scientific advances made during the last decade on understanding the physicochemical and structural modifications of emulsified lipids, mainly from a biophysical science perspective. The review specifically explores different approaches by which the structure and stability of emulsions may be altered to achieve specific lipid digestion kinetics.
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Affiliation(s)
- Alejandra Acevedo-Fani
- Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Harjinder Singh
- Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
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16
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Wilson MH, Ekker SC, Farber SA. Imaging cytoplasmic lipid droplets in vivo with fluorescent perilipin 2 and perilipin 3 knock-in zebrafish. eLife 2021; 10:e66393. [PMID: 34387191 PMCID: PMC8460263 DOI: 10.7554/elife.66393] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 08/10/2021] [Indexed: 12/26/2022] Open
Abstract
Cytoplasmic lipid droplets are highly dynamic storage organelles that are critical for cellular lipid homeostasis. While the molecular details of lipid droplet dynamics are a very active area of investigation, this work has been primarily performed in cultured cells. Taking advantage of the powerful transgenic and in vivo imaging opportunities available in zebrafish, we built a suite of tools to study lipid droplets in real time from the subcellular to the whole organism level. Fluorescently tagging the lipid droplet-associated proteins, perilipin 2 and perilipin 3, in the endogenous loci permits visualization of lipid droplets in the intestine, liver, and adipose tissue. Using these tools, we found that perilipin 3 is rapidly loaded on intestinal lipid droplets following a high-fat meal and later replaced by perilipin 2. These powerful new tools will facilitate studies on the role of lipid droplets in different tissues, under different genetic and physiological manipulations, and in a variety of human disease models.
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Affiliation(s)
- Meredith H Wilson
- Carnegie Institution for Science Department of EmbryologyBaltimoreUnited States
| | - Stephen C Ekker
- Department of Biochemistry and Molecular Biology, Mayo ClinicRochesterUnited States
| | - Steven A Farber
- Carnegie Institution for Science Department of EmbryologyBaltimoreUnited States
- Johns Hopkins University Department of BiologyBaltimoreUnited States
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17
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Zembroski AS, Xiao C, Buhman KK. The Roles of Cytoplasmic Lipid Droplets in Modulating Intestinal Uptake of Dietary Fat. Annu Rev Nutr 2021; 41:79-104. [PMID: 34283920 DOI: 10.1146/annurev-nutr-110320-013657] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dietary fat absorption is required for health but also contributes to hyperlipidemia and metabolic disease when dysregulated. One step in the process of dietary fat absorption is the formation of cytoplasmic lipid droplets (CLDs) in small intestinal enterocytes; these CLDs serve as dynamic triacylglycerol storage organelles that influence the rate at which dietary fat is absorbed. Recent studies have uncovered novel factors regulating enterocyte CLD metabolism that in turn influence the absorption of dietary fat. These include peroxisome proliferator-activated receptor α activation, compartmentalization of different lipid pools, the gut microbiome, liver X receptor and farnesoid X receptor activation, obesity, and physiological factors stimulating CLD mobilization. Understanding how enterocyte CLD metabolism is regulated is key in modulating the absorption of dietary fat in the prevention of hyperlipidemia and its associated metabolic disorders. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Alyssa S Zembroski
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana 47907, USA;
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18
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Zembroski AS, D’Aquila T, Buhman KK. Characterization of cytoplasmic lipid droplets in each region of the small intestine of lean and diet-induced obese mice in response to dietary fat. Am J Physiol Gastrointest Liver Physiol 2021; 321:G75-G86. [PMID: 34009042 PMCID: PMC8321799 DOI: 10.1152/ajpgi.00084.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The absorptive cells of the small intestine, namely, enterocytes, contribute to postprandial blood lipid levels by secreting dietary triacylglycerol in chylomicrons. The rate and amount of dietary triacylglycerol absorbed vary along the length of the small intestine. Excess dietary triacylglycerol not immediately secreted in chylomicrons can be temporarily stored in cytoplasmic lipid droplets (CLDs) and repackaged in chylomicrons at later times. The characteristics of CLDs, including their size, number per cell, and associated proteins, may influence CLD metabolism and reflect differences in lipid processing or storage in each intestinal region. However, it is unknown whether the characteristics or proteomes of CLDs differ in enterocytes of each intestine region in response to dietary fat. Furthermore, it is unclear if obesity influences the characteristics or proteomes of CLDs in each intestine region. To address this, we used transmission electron microscopy and shotgun liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis to assess the characteristics and proteome of CLDs in the proximal, middle, and distal regions of the small intestine of lean and diet-induced obese (DIO) mice 2 h after an oil gavage. We identified differences in lipid storage along the length of the small intestine and between lean and DIO mice, as well as distinct CLD proteomes reflecting potentially unique roles of CLDs in each region. This study reveals differences in lipid processing along the length of the small intestine in response to dietary fat in lean and DIO mice and reflects distinct features of the proximal, middle, distal region of the small intestine.NEW & NOTEWORTHY This study reflects the dynamics of fat absorption along the length of the small intestine in lean and obese mice in the physiological response to dietary fat. We identified unique features of cytoplasmic lipid droplets (CLDs) in the proximal, middle, and distal regions of the small intestine of lean and obese mice that may contribute to regional differences in dietary fat processing, absorption, or CLD metabolism.
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Affiliation(s)
| | - Theresa D’Aquila
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Kimberly K. Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
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19
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Guendel F, Kofoed-Branzk M, Gronke K, Tizian C, Witkowski M, Cheng HW, Heinz GA, Heinrich F, Durek P, Norris PS, Ware CF, Ruedl C, Herold S, Pfeffer K, Hehlgans T, Waisman A, Becher B, Giannou AD, Brachs S, Ebert K, Tanriver Y, Ludewig B, Mashreghi MF, Kruglov AA, Diefenbach A. Group 3 Innate Lymphoid Cells Program a Distinct Subset of IL-22BP-Producing Dendritic Cells Demarcating Solitary Intestinal Lymphoid Tissues. Immunity 2021; 53:1015-1032.e8. [PMID: 33207209 DOI: 10.1016/j.immuni.2020.10.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/20/2020] [Accepted: 10/16/2020] [Indexed: 12/23/2022]
Abstract
Solitary intestinal lymphoid tissues such as cryptopatches (CPs) and isolated lymphoid follicles (ILFs) constitute steady-state activation hubs containing group 3 innate lymphoid cells (ILC3) that continuously produce interleukin (IL)-22. The outer surface of CPs and ILFs is demarcated by a poorly characterized population of CD11c+ cells. Using genome-wide single-cell transcriptional profiling of intestinal mononuclear phagocytes and multidimensional flow cytometry, we found that CP- and ILF-associated CD11c+ cells were a transcriptionally distinct subset of intestinal cDCs, which we term CIA-DCs. CIA-DCs required programming by CP- and ILF-resident CCR6+ ILC3 via lymphotoxin-β receptor signaling in cDCs. CIA-DCs differentially expressed genes associated with immunoregulation and were the major cellular source of IL-22 binding protein (IL-22BP) at steady state. Mice lacking CIA-DC-derived IL-22BP exhibited diminished expression of epithelial lipid transporters, reduced lipid resorption, and changes in body fat homeostasis. Our findings provide insight into the design principles of an immunoregulatory checkpoint controlling nutrient absorption.
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Affiliation(s)
- Fabian Guendel
- Laboratory of Innate Immunity, Department of Microbiology, Infectious Diseases and Immunology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10117 Berlin, Germany; Mucosal and Developmental Immunology, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Michael Kofoed-Branzk
- Laboratory of Innate Immunity, Department of Microbiology, Infectious Diseases and Immunology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10117 Berlin, Germany; Mucosal and Developmental Immunology, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Konrad Gronke
- Laboratory of Innate Immunity, Department of Microbiology, Infectious Diseases and Immunology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10117 Berlin, Germany; Mucosal and Developmental Immunology, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Caroline Tizian
- Laboratory of Innate Immunity, Department of Microbiology, Infectious Diseases and Immunology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10117 Berlin, Germany; Mucosal and Developmental Immunology, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Mario Witkowski
- Laboratory of Innate Immunity, Department of Microbiology, Infectious Diseases and Immunology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10117 Berlin, Germany; Mucosal and Developmental Immunology, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Hung-Wei Cheng
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Gitta Anne Heinz
- Therapeutic Gene Regulation, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Frederik Heinrich
- Therapeutic Gene Regulation, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Pawel Durek
- Therapeutic Gene Regulation, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany
| | - Paula S Norris
- Laboratory of Molecular Immunology, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Carl F Ware
- Laboratory of Molecular Immunology, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Christiane Ruedl
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore
| | - Susanne Herold
- Department of Internal Medicine II, Universities of Giessen and Marburg Lung Center, member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Klaus Pfeffer
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Thomas Hehlgans
- Regensburg Center for Interventional Immunology (RCI), Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany; Chair for Immunology, Regensburg University, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Ari Waisman
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Burkhard Becher
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Anastasios D Giannou
- Section of Molecular Immunology und Gastroenterology, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Sebastian Brachs
- Department of Endocrinology and Metabolism, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany; Center for Cardiovascular Research (CCR), Charité-Universitätsmedizin Berlin, Hessische Strasse 3-4, 10115 Berlin, Germany
| | - Karolina Ebert
- Institute of Medical Microbiology and Hygiene, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Yakup Tanriver
- Institute of Medical Microbiology and Hygiene, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Department of Internal Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Burkhard Ludewig
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland; Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Mir-Farzin Mashreghi
- Therapeutic Gene Regulation, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany; BIH Center for Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Andrey A Kruglov
- Microbiota and Chronic Inflammation, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany; Belozersky Institute of Physico-Chemical Biology and Biological Faculty, M.V. Lomonosov Moscow State University, Moscow 119234, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Andreas Diefenbach
- Laboratory of Innate Immunity, Department of Microbiology, Infectious Diseases and Immunology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10117 Berlin, Germany; Mucosal and Developmental Immunology, Deutsches Rheuma-Forschungszentrum (DRFZ), an institute of the Leibniz Association, 10117 Berlin, Germany.
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20
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Schittmayer M, Vujic N, Darnhofer B, Korbelius M, Honeder S, Kratky D, Birner-Gruenberger R. Spatially Resolved Activity-based Proteomic Profiles of the Murine Small Intestinal Lipases. Mol Cell Proteomics 2020; 19:2104-2115. [PMID: 33023980 PMCID: PMC7710144 DOI: 10.1074/mcp.ra120.002171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/28/2020] [Indexed: 01/05/2023] Open
Abstract
Despite the crucial function of the small intestine in nutrient uptake our understanding of the molecular events underlying the digestive function is still rudimentary. Recent studies demonstrated that enterocytes do not direct the entire dietary triacylglycerol toward immediate chylomicron synthesis. Especially after high-fat challenges, parts of the resynthesized triacylglycerol are packaged into cytosolic lipid droplets for transient storage in the endothelial layer of the small intestine. The reason for this temporary storage of triacylglycerol is not completely understood. To utilize lipids from cytosolic lipid droplets for chylomicron synthesis in the endoplasmic reticulum, stored triacylglycerol has to be hydrolyzed either by cytosolic lipolysis or lipophagy. Interestingly, triacylglycerol storage and chylomicron secretion rates are unevenly distributed along the small intestine, with the proximal jejunum exhibiting the highest intermittent storage capacity. We hypothesize that correlating hydrolytic enzyme activities with the reported distribution of triacylglycerol storage and chylomicron secretion in different sections of the small intestine is a promising strategy to determine key enzymes in triacylglycerol remobilization. We employed a serine hydrolase specific activity-based labeling approach in combination with quantitative proteomics to identify and rank hydrolases based on their relative activity in 11 sections of the small intestine. Moreover, we identified several clusters of enzymes showing similar activity distribution along the small intestine. Merging our activity-based results with substrate specificity and subcellular localization known from previous studies, carboxylesterase 2e and arylacetamide deacetylase emerge as promising candidates for triacylglycerol mobilization from cytosolic lipid droplets in enterocytes.
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Affiliation(s)
- Matthias Schittmayer
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna, Austria; Diagnostic and Research Institute of Pathology, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
| | - Nemanja Vujic
- Gottfried Schatz Research Center, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Barbara Darnhofer
- Diagnostic and Research Institute of Pathology, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Melanie Korbelius
- Gottfried Schatz Research Center, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Sophie Honeder
- Diagnostic and Research Institute of Pathology, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
| | - Ruth Birner-Gruenberger
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna, Austria; Diagnostic and Research Institute of Pathology, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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21
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Korbelius M, Vujic N, Sachdev V, Obrowsky S, Rainer S, Gottschalk B, Graier WF, Kratky D. ATGL/CGI-58-Dependent Hydrolysis of a Lipid Storage Pool in Murine Enterocytes. Cell Rep 2020; 28:1923-1934.e4. [PMID: 31412256 PMCID: PMC6713565 DOI: 10.1016/j.celrep.2019.07.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 03/29/2019] [Accepted: 07/11/2019] [Indexed: 12/22/2022] Open
Abstract
As circulating lipid levels are balanced by the rate of lipoprotein release and clearance from the plasma, lipid absorption in the small intestine critically contributes to the maintenance of whole-body lipid homeostasis. Within enterocytes, excessive triglycerides are transiently stored as cytosolic lipid droplets (cLDs), and their mobilization sustains lipid supply during interprandial periods. Using mice lacking adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58) exclusively in the intestine (intestine-specific double KO [iDKO]), we show that ATGL/CGI-58 are not involved in providing substrates for chylomicron synthesis. Massive intestinal cLD accumulation in iDKO mice independent of dietary lipids together with inefficient lipid incorporation into cLDs in the early absorption phase demonstrate the existence of a secretion/re-uptake cycle, corroborating the availability of two diverse cLD pools. This study identified ATGL/CGI-58 as critical players in the catabolism of basolaterally (blood) derived lipids and highlights the necessity to modify the current model of intestinal lipid metabolism.
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Affiliation(s)
- Melanie Korbelius
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Nemanja Vujic
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Vinay Sachdev
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Sascha Obrowsky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Silvia Rainer
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Benjamin Gottschalk
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria; BioTechMed-Graz, 8010 Graz, Styria, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria; BioTechMed-Graz, 8010 Graz, Styria, Austria.
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22
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Markovic MA, Srikrishnaraj A, Tsang D, Brubaker PL. Requirement for the intestinal epithelial insulin-like growth factor-1 receptor in the intestinal responses to glucagon-like peptide-2 and dietary fat. FASEB J 2020; 34:6628-6640. [PMID: 32212202 DOI: 10.1096/fj.202000169r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/28/2020] [Accepted: 03/10/2020] [Indexed: 12/13/2022]
Abstract
The intestinal hormone, glucagon-like peptide-2 (GLP-2), enhances the enterocyte chylomicron production. However, GLP-2 is known to require the intestinal-epithelial insulin-like growth factor-1 receptor (IE-IGF-1R) for its other actions to increase intestinal growth and barrier function. The role of the IE-IGF-1R in enterocyte lipid handling was thus tested in the GLP-2 signaling pathway, as well as in response to a Western diet (WD). IE-IGF-1R knockout (KO) and control mice were treated for 11 days with h(GLY2 )GLP-2 or fed a WD for 18 weeks followed by a duodenal fat tolerance test with C14 -labeled triolein. Human Caco-2BBE cells were treated with an IGF-1R antagonist or signaling inhibitors to determine triglyceride-associated protein expression. The IE-IGF-1R was required for GLP-2-induced increases in CD36 and FATP-4 in chow-fed mice, and for expression in vitro; FATP-4 also required PI3K/Akt. Although WD-fed IE-IGF-1R KO mice demonstrated normal CD36 expression, the protein was incorrectly localized 2h post-duodenal fat administration. IE-IGF-1R KO also prevented the WD-induced increase in MTP and decrease in APOC3, increased jejunal mucosal C14 -fat accumulation, and elevated plasma triglyceride and C14 -fat levels. Collectively, these studies elucidate new roles for the IE-IGF-1R in enterocyte lipid handling, under basal conditions and in response to GLP-2 and WD-feeding.
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Affiliation(s)
| | | | - Derek Tsang
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Patricia L Brubaker
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Department of Medicine, University of Toronto, Toronto, ON, Canada
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23
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Trehalose itself plays a critical role on lipid metabolism: Trehalose increases jejunum cytoplasmic lipid droplets which negatively correlated with mesenteric adipocyte size in both HFD-fed trehalase KO and WT mice. Nutr Metab (Lond) 2020; 17:22. [PMID: 32206077 PMCID: PMC7081596 DOI: 10.1186/s12986-020-00443-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/12/2020] [Indexed: 12/19/2022] Open
Abstract
Background Trehalose is a functional disaccharide that has anti-metabolic activities such as suppression of adipocyte hypertrophy in mice and alleviation of impaired glucose tolerance in humans. Trehalase hydrolyzes trehalose in the small intestine into two glucose molecules. In this study, we investigated whether trehalose can suppress adipocyte hypertrophy in mice in the presence or absence of trehalase. Methods Trehalase knockout (KO) mice and wild-type (WT) mice were fed a high fat diet (HFD) and administered water with 0.3% (w/v) or without trehalose for 8 weeks. At the end of the experimental period, mesenteric adipose tissues and the small intestine were collected and the adipocyte size and proportion of cytoplasmic lipid droplets (CLDs, %) in jejunum epithelium were measured by image analysis. Results Trehalose treatment was associated with suppressed adipocyte hypertrophy in both trehalase KO and WT mice. The rate of CLDs in the jejunal epithelium was increased in both trehalase KO and WT mice given water containing trehalose relative to untreated control mice. There was a negative correlation between jejunal epithelial lipid droplet volume and mesenteric adipocyte size. Chylomicron-TG tended to be decreased in both trehalose-treated trehalase KO and WT mice. Addition of trehalose to differentiated Caco-2 cells in vitro increased intracytoplasmic lipid droplets and decreased secretion of the chylomicron marker ApoB-48. Moreover, the jejunal epithelium containing lipid droplets falled into the intestinal lumen, and triglyceride (TG) levels in feces tended to be higher in the KO/HFD/Tre group than in the KO/HFD/Water group. Since then, the accumulation of CLDs has been reported to suppress CM secretion, and along with our results, the effect of trehalose to increase jejunum CLDs may induce adipocyte hypertrophy. Conclusions The suppression of adipocyte hypertrophy in the presence and absence of trehalase indicates that trehalose mediates effects prior to being hydrolyzed into glucose. In both trehalase KO and WT mice, trehalose treatment increased the rate of CLDs in jejunal epithelium, reduced chylomicron migration from the intestinal epithelium to the periphery, and suppressed adipocyte hypertrophy. Thus, trehalose ingestion could prevent metabolic syndrome by trapping fat droplets in the intestinal epithelium and suppressing rapid increases in chylomicrons.
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24
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Lundåsen T, Pedrelli M, Bjørndal B, Rozell B, Kuiper RV, Burri L, Pavanello C, Turri M, Skorve J, Berge RK, Alexson SEH, Tillander V. The PPAR pan-agonist tetradecylthioacetic acid promotes redistribution of plasma cholesterol towards large HDL. PLoS One 2020; 15:e0229322. [PMID: 32176696 PMCID: PMC7075573 DOI: 10.1371/journal.pone.0229322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 02/04/2020] [Indexed: 12/16/2022] Open
Abstract
Tetradecylthioacetic acid (TTA) is a synthetic fatty acid with a sulfur substitution in the β-position. This modification renders TTA unable to undergo complete β-oxidation and increases its biological activity, including activation of peroxisome proliferator activated receptors (PPARs) with preference for PPARα. This study investigated the effects of TTA on lipid and lipoprotein metabolism in the intestine and liver of mice fed a high fat diet (HFD). Mice receiving HFD supplemented with 0.75% (w/w) TTA had significantly lower body weights compared to mice fed the diet without TTA. Plasma triacylglycerol (TAG) was reduced 3-fold with TTA treatment, concurrent with increase in liver TAG. Total cholesterol was unchanged in plasma and liver. However, TTA promoted a shift in the plasma lipoprotein fractions with an increase in larger HDL particles. Histological analysis of the small intestine revealed a reduced size of lipid droplets in enterocytes of TTA treated mice, accompanied by increased mRNA expression of fatty acid transporter genes. Expression of the cholesterol efflux pump Abca1 was induced in the small intestine, but not in the liver. Scd1 displayed markedly increased mRNA and protein expression in the intestine of the TTA group. It is concluded that TTA treatment of HFD fed mice leads to increased expression of genes involved in uptake and transport of fatty acids and HDL cholesterol in the small intestine with concomitant changes in the plasma profile of smaller lipoproteins.
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Affiliation(s)
- Thomas Lundåsen
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Matteo Pedrelli
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
- Translational Science and Experimental Medicine, Research and Early Development, Cardiovascular Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Bodil Bjørndal
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Sports, Physical activity and Food, Faculty of Education, Arts and Sports, Western Norway University of Applied Sciences, Bergen, Norway
- * E-mail: (BB); (VT)
| | - Björn Rozell
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Raoul V. Kuiper
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Lena Burri
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Chiara Pavanello
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro Enrica Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Marta Turri
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro Enrica Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Jon Skorve
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Rolf K. Berge
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
| | | | - Veronika Tillander
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
- * E-mail: (BB); (VT)
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25
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Bittel AJ, Bittel DC, Mittendorfer B, Patterson BW, Okunade AL, Yoshino J, Porter LC, Abumrad NA, Reeds DN, Cade WT. A single bout of resistance exercise improves postprandial lipid metabolism in overweight/obese men with prediabetes. Diabetologia 2020; 63:611-623. [PMID: 31873788 PMCID: PMC7002271 DOI: 10.1007/s00125-019-05070-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 11/06/2019] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Prediabetes is associated with postprandial hypertriacylglycerolaemia. Resistance exercise acutely lowers postprandial plasma triacylglycerol (TG); however, the changes in lipid metabolism that mediate this reduction are poorly understood. The aim of this study was to identify the constitutive metabolic mechanisms underlying the changes in postprandial lipid metabolism after resistance exercise in obese men with prediabetes. METHODS We evaluated the effect of a single bout of whole-body resistance exercise (seven exercises, three sets, 10-12 repetitions at 80% of one-repetition maximum) on postprandial lipid metabolism in ten middle-aged (50 ± 9 years), overweight/obese (BMI: 33 ± 3 kg/m2), sedentary men with prediabetes (HbA1c >38 but <48 mmol/mol [>5.7% but <6.5%]), or fasting plasma glucose >5.6 mmol/l but <7.0 mmol/l or 2 h OGTT glucose >7.8 mmol/l but <11.1 mmol/l). We used a randomised, crossover design with a triple-tracer mixed meal test (ingested [(13C4)3]tripalmitin, i.v. [U-13C16]palmitate and [2H5]glycerol) to evaluate chylomicron-TG and total triacylglycerol-rich lipoprotein (TRL)-TG kinetics. We used adipose tissue and skeletal muscle biopsies to evaluate the expression of genes regulating lipolysis and lipid oxidation, skeletal muscle respirometry to evaluate oxidative capacity, and indirect calorimetry to assess whole-body lipid oxidation. RESULTS The single bout of resistance exercise reduced the lipaemic response to a mixed meal in obese men with prediabetes without changing chylomicron-TG or TRL-TG fractional clearance rates. However, resistance exercise reduced endogenous and meal-derived fatty acid incorporation into chylomicron-TG and TRL-TG. Resistance exercise also increased whole-body lipid oxidation, skeletal muscle mitochondrial respiration, oxidative gene expression in skeletal muscle, and the expression of key lipolysis genes in adipose tissue. CONCLUSIONS/INTERPRETATION A single bout of resistance exercise improves postprandial lipid metabolism in obese men with prediabetes, which may mitigate the risk for cardiovascular disease and type 2 diabetes.
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Affiliation(s)
- Adam J Bittel
- Program in Physical Therapy, Washington University, St Louis, Campus Box 8502, 4444 Forest Park Ave., St Louis, MO, 63110, USA.
| | - Daniel C Bittel
- Program in Physical Therapy, Washington University, St Louis, Campus Box 8502, 4444 Forest Park Ave., St Louis, MO, 63110, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Bruce W Patterson
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Adewole L Okunade
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Jun Yoshino
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Lane C Porter
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Nada A Abumrad
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Dominic N Reeds
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - W Todd Cade
- Program in Physical Therapy, Washington University, St Louis, Campus Box 8502, 4444 Forest Park Ave., St Louis, MO, 63110, USA
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26
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Regulation of intestinal lipid metabolism: current concepts and relevance to disease. Nat Rev Gastroenterol Hepatol 2020; 17:169-183. [PMID: 32015520 DOI: 10.1038/s41575-019-0250-7] [Citation(s) in RCA: 232] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/02/2019] [Indexed: 12/21/2022]
Abstract
Lipids entering the gastrointestinal tract include dietary lipids (triacylglycerols, cholesteryl esters and phospholipids) and endogenous lipids from bile (phospholipids and cholesterol) and from shed intestinal epithelial cells (enterocytes). Here, we comprehensively review the digestion, uptake and intracellular re-synthesis of intestinal lipids as well as their packaging into pre-chylomicrons in the endoplasmic reticulum, their modification in the Golgi apparatus and the exocytosis of the chylomicrons into the lamina propria and subsequently to lymph. We also discuss other fates of intestinal lipids, including intestinal HDL and VLDL secretion, cytosolic lipid droplets and fatty acid oxidation. In addition, we highlight the applicability of these findings to human disease and the development of therapeutics targeting lipid metabolism. Finally, we explore the emerging role of the gut microbiota in modulating intestinal lipid metabolism and outline key questions for future research.
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27
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Yu L, Li Y, Grisé A, Wang H. CGI-58: Versatile Regulator of Intracellular Lipid Droplet Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:197-222. [PMID: 32705602 PMCID: PMC8063591 DOI: 10.1007/978-981-15-6082-8_13] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Comparative gene identification-58 (CGI-58), also known as α/β-hydrolase domain-containing 5 (ABHD5), is a member of a large family of proteins containing an α/β-hydrolase-fold. CGI-58 is well-known as the co-activator of adipose triglyceride lipase (ATGL), which is a key enzyme initiating cytosolic lipid droplet lipolysis. Mutations in either the human CGI-58 or ATGL gene cause an autosomal recessive neutral lipid storage disease, characterized by the excessive accumulation of triglyceride (TAG)-rich lipid droplets in the cytoplasm of almost all cell types. CGI-58, however, has ATGL-independent functions. Distinct phenotypes associated with CGI-58 deficiency commonly include ichthyosis (scaly dry skin), nonalcoholic steatohepatitis, and hepatic fibrosis. Through regulated interactions with multiple protein families, CGI-58 controls many metabolic and signaling pathways, such as lipid and glucose metabolism, energy balance, insulin signaling, inflammatory responses, and thermogenesis. Recent studies have shown that CGI-58 regulates the pathogenesis of common metabolic diseases in a tissue-specific manner. Future studies are needed to molecularly define ATGL-independent functions of CGI-58, including the newly identified serine protease activity of CGI-58. Elucidation of these versatile functions of CGI-58 may uncover fundamental cellular processes governing lipid and energy homeostasis, which may help develop novel approaches that counter against obesity and its associated metabolic sequelae.
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Affiliation(s)
- Liqing Yu
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Yi Li
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alison Grisé
- College of Computer, Math, and Natural Sciences, College of Behavioral and Social Sciences, University of Maryland, College Park, MD, USA
| | - Huan Wang
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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28
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Stahel P, Xiao C, Davis X, Tso P, Lewis GF. Glucose and GLP-2 (Glucagon-Like Peptide-2) Mobilize Intestinal Triglyceride by Distinct Mechanisms. Arterioscler Thromb Vasc Biol 2019; 39:1565-1573. [PMID: 31294621 DOI: 10.1161/atvbaha.119.313011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Dietary triglycerides are partially retained in the intestine within intracellular or extracellular compartments, which can be rapidly mobilized in response to several stimuli, including glucose and GLP-2 (glucagon-like peptide-2). To elucidate the mechanism of intestinal lipid mobilization, this study examined the patterns and time course of lymph flow and triglycerides after glucose and GLP-2 treatment in rats. Approach and Results: Lymph flow, triglyceride concentration, and triglyceride output were assessed in mesenteric lymph duct-cannulated rats in response to an intraduodenal (i.d.) lipid bolus followed 5 hours later by either (1) i.d. saline+intraperitoneal (i.p.) saline (placebo), (2) i.d. glucose plus i.p. saline, (3) i.d. saline+i.p. GLP-2, or (4) i.d. glucose+i.p. GLP-2. GLP-2 and glucose administered alone or in combination stimulated total triglyceride output to a similar extent, but the timing and pattern of stimulation differed markedly. Whereas GLP-2 rapidly increased lymph flow with no effect on lymph triglyceride concentration or triglyceride:apoB48 (apolipoprotein B48) ratio (a surrogate marker of chylomicron size) compared with placebo, glucose transiently decreased lymph flow followed by delayed stimulation of lymph flow and increased lymph triglyceride concentration and triglyceride:apoB48 ratio. CONCLUSIONS Glucose and GLP-2 robustly enhanced intestinal triglyceride output in rats but with different effects on lymph flow, lymph triglyceride concentration, and chylomicron size. GLP-2 stimulated triglyceride output primarily by enhancing lymph flow with no effect on chylomicron size, whereas glucose mobilized intestinal triglycerides, stimulating secretion of larger chylomicrons. This suggests that these 2 stimuli mobilize intestinal lipid by different mechanisms.
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Affiliation(s)
- Priska Stahel
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, ON, Canada (P.S., C.X., G.F.L.)
| | - Changting Xiao
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, ON, Canada (P.S., C.X., G.F.L.)
| | - Xenia Davis
- Department of Pathology and Laboratory Medicine, University of Cincinnati, OH (X.D., P.T.)
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, OH (X.D., P.T.)
| | - Gary F Lewis
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, ON, Canada (P.S., C.X., G.F.L.)
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29
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Shokry E, Raab R, Kirchberg FF, Hellmuth C, Klingler M, Demmelmair H, Koletzko B, Uhl O. Prolonged monitoring of postprandial lipid metabolism after a western meal rich in linoleic acid and carbohydrates. Appl Physiol Nutr Metab 2019; 44:1189-1198. [PMID: 30893569 DOI: 10.1139/apnm-2018-0798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Today, awareness has been raised regarding high consumption of n-6 polyunsaturated fatty acids (PUFA) in western diets. A comprehensive analysis of total and individual postprandial fatty acids profiles would provide insights into metabolic turnover and related health effects. After an overnight fast, 9 healthy adults consumed a mixed meal comprising 97 g carbohydrate and 45 g fat, of which 26.4 g was linoleic acid (LA). Nonesterified fatty acids (NEFA), phospholipid fatty acids (PL-FA) and triacylglycerol fatty acids (TG-FA) were monitored in plasma samples, at baseline and hourly over a 7-h postprandial period. Total TG-FA concentration peaked at 2 h after the meal and steadily decreased thereafter. LA from TG18:2n-6 and behenic acid from TG22:0 showed the highest response among TG-FA, with a biphasic response detected for the former. PL-FA exhibited no change. Total NEFA initially decreased to nadir at 1 h, then increased to peak at 7 h. The individual NEFA showed the same response curve except LA and some very-long-chain saturated fatty acids (VLCSFA, ≥20 carbon chain length) that markedly increased shortly after the meal intake. The similarities and dissimilarities in lipid profiles between study subjects at different time points were visualized using nonmetric multi-dimensional scaling. Overall, the results indicate that postprandial levels of LA and VLCSFA, either as NEFA or TG, were most affected by the test meal, which might provide an explanation for the health effects of this dietary lifestyle characterized by high intake of mixed meals rich in n-6 PUFA.
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Affiliation(s)
- Engy Shokry
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Roxana Raab
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Franca F Kirchberg
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Christian Hellmuth
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Mario Klingler
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Hans Demmelmair
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Berthold Koletzko
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
| | - Olaf Uhl
- Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.,Ludwig-Maximilians-Universität (LMU) München, Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany
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30
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Maresch LK, Benedikt P, Feiler U, Eder S, Zierler KA, Taschler U, Kolleritsch S, Eichmann TO, Schoiswohl G, Leopold C, Wieser BI, Lackner C, Rülicke T, van Klinken J, Kratky D, Moustafa T, Hoefler G, Haemmerle G. Intestine-Specific Overexpression of Carboxylesterase 2c Protects Mice From Diet-Induced Liver Steatosis and Obesity. Hepatol Commun 2018; 3:227-245. [PMID: 30766961 PMCID: PMC6357831 DOI: 10.1002/hep4.1292] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/29/2018] [Indexed: 12/27/2022] Open
Abstract
Murine hepatic carboxylesterase 2c (Ces2c) and the presumed human ortholog carboxylesterase 2 (CES2) have been implicated in the development of nonalcoholic fatty liver disease (NAFLD) in mice and obese humans. These studies demonstrated that Ces2c hydrolyzes triglycerides (TGs) in hepatocytes. Interestingly, Ces2c/CES2 is most abundantly expressed in the intestine, indicating a role of Ces2c/CES2 in intestinal TG metabolism. Here we show that Ces2c is an important enzyme in intestinal lipid metabolism in mice. Intestine-specific Ces2c overexpression (Ces2cint) provoked increased fatty acid oxidation (FAO) in the small intestine accompanied by enhanced chylomicron clearance from the circulation. As a consequence, high-fat diet-fed Ces2cint mice were resistant to excessive diet-induced weight gain and adipose tissue expansion. Notably, intestinal Ces2c overexpression increased hepatic insulin sensitivity and protected mice from NAFLD development. Although lipid absorption was not affected in Ces2cint mice, fecal energy content was significantly increased. Mechanistically, we demonstrate that Ces2c is a potent neutral lipase, which efficiently hydrolyzes TGs and diglycerides (DGs) in the small intestine, thereby generating fatty acids (FAs) for FAO and monoglycerides (MGs) and DGs for potential re-esterification. Consequently, the increased availability of MGs and DGs for re-esterification and primordial apolipoprotein B48 particle lipidation may increase chylomicron size, ultimately mediating more efficient chylomicron clearance from the circulation. Conclusion: This study suggests a critical role for Ces2c in intestinal lipid metabolism and highlights the importance of intestinal lipolysis to protect mice from the development of hepatic insulin resistance, NAFLD, and excessive diet-induced weight gain during metabolic stress.
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Affiliation(s)
| | - Pia Benedikt
- Institute of Molecular Biosciences University of Graz Graz Austria
| | - Ursula Feiler
- Institute of Molecular Biosciences University of Graz Graz Austria
| | - Sandra Eder
- Institute of Molecular Biosciences University of Graz Graz Austria
| | | | - Ulrike Taschler
- Institute of Molecular Biosciences University of Graz Graz Austria
| | | | | | | | - Christina Leopold
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry Medical University of Graz Graz Austria
| | - Beatrix I Wieser
- Diagnostic & Research Center for Molecular BioMedicine Institute of Pathology Medical University of Graz Graz Austria
| | - Caroline Lackner
- Diagnostic & Research Center for Molecular BioMedicine Institute of Pathology Medical University of Graz Graz Austria
| | - Thomas Rülicke
- Institute of Laboratory Animal Science University of Veterinary Medicine Wien Austria
| | - Jan van Klinken
- Department of Human Genetics Leiden University Medical Centre Leiden the Netherlands
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry Medical University of Graz Graz Austria
| | - Tarek Moustafa
- Division of Gastroenterology and Hepatology Medical University Graz Graz Austria
| | - Gerald Hoefler
- Diagnostic & Research Center for Molecular BioMedicine Institute of Pathology Medical University of Graz Graz Austria
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Weinrauch AM, Glover CN, Goss GG. Lipid acquisition and tissue storage in hagfish: new insights from an ancient vertebrate. J Comp Physiol B 2018; 189:37-45. [DOI: 10.1007/s00360-018-1196-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/15/2018] [Accepted: 11/22/2018] [Indexed: 11/29/2022]
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Xiao C, Stahel P, Lewis GF. Regulation of Chylomicron Secretion: Focus on Post-Assembly Mechanisms. Cell Mol Gastroenterol Hepatol 2018; 7:487-501. [PMID: 30819663 PMCID: PMC6396431 DOI: 10.1016/j.jcmgh.2018.10.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/23/2018] [Accepted: 10/25/2018] [Indexed: 02/06/2023]
Abstract
Rapid and efficient digestion and absorption of dietary triglycerides and other lipids by the intestine, the packaging of those lipids into lipoprotein chylomicron (CM) particles, and their secretion via the lymphatic duct into the blood circulation are essential in maintaining whole-body lipid and energy homeostasis. Biosynthesis and assembly of CMs in enterocytes is a complex multistep process that is subject to regulation by intracellular signaling pathways as well as by hormones, nutrients, and neural factors extrinsic to the enterocyte. Dysregulation of this process has implications for health and disease, contributing to dyslipidemia and a potentially increased risk of atherosclerotic cardiovascular disease. There is increasing recognition that, besides intracellular regulation of CM assembly and secretion, regulation of postassembly pathways also plays important roles in CM secretion. This review examines recent advances in our understanding of the regulation of CM secretion in relation to mobilization of intestinal lipid stores, drawing particular attention to post-assembly regulatory mechanisms, including intracellular trafficking of triglycerides in enterocytes, CM mobilization from the lamina propria, and regulated transport of CM by intestinal lymphatics.
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Affiliation(s)
- Changting Xiao
- Changting Xiao, PhD, Princess Margaret Cancer Research Tower 10-203, Medical and Related Science Centre, 101 College Street, Toronto, Ontario M5G 1L7, Canada. fax: (416) 581-7487.
| | | | - Gary F. Lewis
- Correspondence Address correspondence to: Gary F. Lewis, MD, FRCPC, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada. fax: (416) 340-3314.
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Hung YH, Buhman KK. DGAT1 deficiency disrupts lysosome function in enterocytes during dietary fat absorption. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:587-595. [PMID: 30342099 DOI: 10.1016/j.bbalip.2018.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/27/2018] [Accepted: 10/13/2018] [Indexed: 11/25/2022]
Abstract
Enterocytes, the absorptive cells of the small intestine, mediate the process of dietary fat absorption by secreting triacylglycerol (TAG) into circulation. When levels of dietary fat are high, TAG is stored in cytoplasmic lipid droplets (CLDs) and sequentially hydrolyzed for ultimate secretion. Mice with deficiency in acyl CoA: diacylglycerol acyltransferase 1 (Dgat1-/- mice) were previously reported to have a reduced rate of intestinal TAG secretion and abnormal TAG accumulation in enterocyte CLDs. This unique intestinal phenotype is critical to their resistance to diet-induced obesity; however, the underlying mechanism remains unclear. Emerging evidence shows that lysosomal TAG hydrolysis contributes to autophagy-mediated CLD mobilization termed lipophagy, and when disrupted results in CLD accumulation. In order to study how lipophagy contributes to the unique intestinal phenotype of Dgat1-/- mice, enterocytes from wild-type (WT) and Dgat1-/- mice were examined at 2 and 6 h after oral oil gavage. Through ultrastructural analysis we observed TAG present within autophagic vesicles (AVs) in mouse enterocytes, suggesting the role of lipophagy in intestinal CLD mobilization during dietary fat absorption. Furthermore, we found that Dgat1-/- mice had abnormal TAG accumulation within AVs and less acidic lysosomes compared to WT mice. Together these findings suggest that the delayed dietary fat absorption seen in Dgat1-/- mice is, in part, due to the dysregulated flux of autophagy-mediated CLD mobilization and impairment of lysosomal acidification in enterocytes. The present study highlights the critical role of lysosome in enterocyte CLD mobilization for proper dietary fat absorption.
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Affiliation(s)
- Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States of America
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States of America.
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Xiao C, Stahel P, Carreiro AL, Hung YH, Dash S, Bookman I, Buhman KK, Lewis GF. Oral Glucose Mobilizes Triglyceride Stores From the Human Intestine. Cell Mol Gastroenterol Hepatol 2018; 7:313-337. [PMID: 30704982 PMCID: PMC6357697 DOI: 10.1016/j.jcmgh.2018.10.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 10/05/2018] [Accepted: 10/05/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS The small intestine regulates plasma triglyceride (TG) concentration. Within enterocytes, dietary TGs are packaged into chylomicrons (CMs) for secretion or stored temporarily in cytoplasmic lipid droplets (CLDs) until further mobilization. We and others have shown that oral and intravenous glucose enhances CM particle secretion in human beings, however, the mechanisms through which this occurs are incompletely understood. METHODS Two separate cohorts of participants ingested a high-fat liquid meal and, 5 hours later, were assigned randomly to ingest either a glucose solution or an equivalent volume of water. In 1 group (N = 6), plasma and lipoprotein TG responses were assessed in a randomized cross-over study. In a separate group (N = 24), duodenal biopsy specimens were obtained 1 hour after ingestion of glucose or water. Ultrastructural and proteomic analyses were performed on duodenal biopsy specimens. RESULTS Compared with water, glucose ingestion increased circulating TGs within 30 minutes, mainly in the CM fraction. It decreased the total number of CLDs and the proportion of large-sized CLDs within enterocytes. We identified 2919 proteins in human duodenal tissue, 270 of which are related to lipid metabolism and 134 of which were differentially present in response to glucose compared with water ingestion. CONCLUSIONS Oral glucose mobilizes TGs stored within enterocyte CLDs to provide substrate for CM synthesis and secretion. Future studies elucidating the underlying signaling pathways may provide mechanistic insights that lead to the development of novel therapeutics for the treatment of hypertriglyceridemia.
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Affiliation(s)
- Changting Xiao
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Alicia L. Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Satya Dash
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Ian Bookman
- Kensington Screening Clinic, Toronto, Ontario, Canada
| | - Kimberly K. Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Gary F. Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada,Correspondence Address correspondence to: Gary F. Lewis, MD, FRCPC, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario, M5G 2C4 Canada. fax: (416) 340-3314.
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Lee J, Ridgway ND. Phosphatidylcholine synthesis regulates triglyceride storage and chylomicron secretion by Caco2 cells. J Lipid Res 2018; 59:1940-1950. [PMID: 30115754 DOI: 10.1194/jlr.m087635] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/09/2018] [Indexed: 11/20/2022] Open
Abstract
Intracellular lipid droplets (LDs) supply fatty acids for energy, membrane biogenesis, and lipoprotein secretion. The surface monolayer of LDs is composed of phospholipids, primarily phosphatidylcholine (PC), that stabilize the neutral lipid core of triglyceride (TG). To determine the relationship between PC synthesis and TG storage and secretion in chylomicrons, we used a model of intestinal-derived human epithelial colorectal adenocarcinoma (Caco2) cells with knockout of PCYT1A, which encodes the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT)α in the CDP-choline pathway, that were treated with the fatty acid oleate. CRISPR/Cas9 knockout of CCTα in Caco2 cells (Caco2-KO cells) reduced PC synthesis by 50%. Compared with Caco2 cells, Caco2-KO cells exposed to oleate had fewer and larger LDs and greater TG accumulation as a result. The addition of exogenous lysophosphatidylcholine to Caco2-KO cells reversed the LD morphology defect. Caco2-KO cells, differentiated into epithelial monolayers, accumulated intracellular TG and had deficient TG and chylomicron-associated apoB48 secretion; apoB100 secretion was unaffected by CCTα knockout or oleate. Metabolic-labeling and LD imaging of Caco2-KO cells indicated preferential shuttling of de novo synthesized TG into larger LDs rather than into chylomicrons. Thus, reduced de novo PC synthesis in Caco2 cells enhances TG storage in large LDs and inhibits apoB48 chylomicron secretion.
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Affiliation(s)
- Jonghwa Lee
- Atlantic Research Center, Departments of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Neale D Ridgway
- Atlantic Research Center, Departments of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
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36
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Xiao C, Stahel P, Carreiro AL, Buhman KK, Lewis GF. Recent Advances in Triacylglycerol Mobilization by the Gut. Trends Endocrinol Metab 2018; 29:151-163. [PMID: 29306629 DOI: 10.1016/j.tem.2017.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/26/2022]
Abstract
Dietary lipid absorption and lipoprotein secretion by the gut are important in maintaining whole-body energy homeostasis and have significant implications for health and disease. The processing of dietary lipids, including storage within and subsequent mobilization and transport from enterocyte cytoplasmic lipid droplets or other intestinal lipid storage pools (including the secretary pathway, lamina propria and lymphatics) and secretion of chylomicrons, involves coordinated steps that are subject to various controls. This review summarizes recent advances in our understanding of the mechanisms that underlie lipid storage and mobilization by small intestinal enterocytes and the intestinal lymphatic vasculature. Therapeutic targeting of lipid processing by the gut may provide opportunities for the treatment and prevention of dyslipidemia, and for improving health status.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Priska Stahel
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Alicia L 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
| | - Gary F Lewis
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
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Abstract
PURPOSE OF REVIEW Dyslipidemia is a major risk factor for atherosclerotic cardiovascular disease (CVD). Lipoproteins secreted by the intestine can contribute to dyslipidemia and may increase risk for CVD. This review focuses on how dietary carbohydrates can impact the production of chylomicrons, thereby influencing plasma concentrations of triglycerides and lipoproteins. RECENT FINDINGS Hypercaloric diets high in monosaccharides can exacerbate postprandial triglyceride concentration. In contrast, isocaloric substitution of monosaccharides into mixed meals has no clear stimulatory or inhibitory effect on postprandial triglycerides. Mechanistic studies with oral ingestion of carbohydrates or elevation of plasma glucose have demonstrated enhanced secretion of chylomicrons. The mechanisms underlying this modulation remain largely unknown but may include enhanced intestinal de novo lipogenesis and mobilization of intestinally stored lipids. SUMMARY The studies reviewed here have implications for dietary recommendations regarding refined carbohydrate intake and prevention of CVD.
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Affiliation(s)
- Priska Stahel
- Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Jejelava N, Kaufman S, Krieger JP, Terra MM, Langhans W, Arnold M. Intestinal lymph as a readout of meal-induced GLP-1 release in an unrestrained rat model. Am J Physiol Regul Integr Comp Physiol 2018; 314:R724-R733. [PMID: 29341824 DOI: 10.1152/ajpregu.00120.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Intestinal lymph supposedly provides a readout for the secretion of intestinal peptides. We here assessed how mesenteric lymph duct (MLD) lymph levels of glucagon-like peptide (GLP-1), insulin, and metabolites [glucose and triglycerides (TG)] evolve after isocaloric high- and low-fat diet (HFD and LFD) meals and how they compare with hepatic portal vein (HPV) plasma levels. Moreover, we examined the effects of intraperitoneally administered GLP-1 (1 or 10 nmol/kg) on these parameters. At 20 min after the HFD meal onset, GLP-1 levels were higher in MLD lymph than in HPV plasma. No such difference occurred with the LFD meal. Intraperitoneal injections of 10 nmol/kg GLP-1 before meals enhanced the meal-induced increases in MLD lymph and HPV plasma GLP-1 levels except for the MLD lymph levels after the HFD meal. Intraperitoneal injection of 1 nmol/kg GLP-1 only increased HPV plasma GLP-1 levels at 60 min after the HFD meal. GLP-1 injections did not increase the MLD lymph or HPV plasma GLP-1 concentrations beyond the physiological range, suggesting that intraperitoneal GLP-1 injections can recapitulate the short-term effects of endogenous GLP-1. Dipeptidyl peptidase IV (DPP-IV) activity in MLD lymph was lower than in HPV plasma, which presumably contributed to the higher levels of GLP-1 in lymph than in plasma. Insulin and glucose showed similar profiles in MLD lymph and HPV plasma, whereas TG levels were higher in lymph than in plasma. These results indicate that intestinal lymph provides a sensitive readout of intestinal peptide release and potential action, in particular when fat-rich diets are consumed.
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Affiliation(s)
- Nino Jejelava
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, ETH Zurich, Switzerland
| | - Sharon Kaufman
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, ETH Zurich, Switzerland
| | - Jean-Philippe Krieger
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, ETH Zurich, Switzerland
| | | | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, ETH Zurich, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, ETH Zurich, Switzerland
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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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PPARγ Modulates Long Chain Fatty Acid Processing in the Intestinal Epithelium. Int J Mol Sci 2017; 18:ijms18122559. [PMID: 29182565 PMCID: PMC5751162 DOI: 10.3390/ijms18122559] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/26/2022] Open
Abstract
Nuclear receptor PPARγ affects lipid metabolism in several tissues, but its role in intestinal lipid metabolism has not been explored. As alterations have been observed in the plasma lipid profile of ad libitum fed intestinal epithelium-specific PPARγ knockout mice (iePPARγKO), we submitted these mice to lipid gavage challenges. Within hours after gavage with long chain unsaturated fatty acid (FA)-rich canola oil, the iePPARγKO mice had higher plasma free FA levels and lower gastric inhibitory polypeptide levels than their wild-type (WT) littermates, and altered expression of incretin genes and lipid metabolism-associated genes in the intestinal epithelium. Gavage with the medium chain saturated FA-rich coconut oil did not result in differences between the two genotypes. Furthermore, the iePPARγKO mice did not exhibit defective lipid uptake and stomach emptying; however, their intestinal transit was more rapid than in WT mice. When fed a canola oil-rich diet for 4.5 months, iePPARγKO mice had higher body lean mass than the WT mice. We conclude that intestinal epithelium PPARγ is activated preferentially by long chain unsaturated FAs compared to medium chain saturated FAs. Furthermore, we hypothesize that the iePPARγKO phenotype originates from altered lipid metabolism and release in epithelial cells, as well as changes in intestinal motility.
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Critical roles for α/β hydrolase domain 5 (ABHD5)/comparative gene identification-58 (CGI-58) at the lipid droplet interface and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1233-1241. [PMID: 28827091 DOI: 10.1016/j.bbalip.2017.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 07/24/2017] [Accepted: 07/31/2017] [Indexed: 01/04/2023]
Abstract
Mutations in the gene encoding comparative gene identification 58 (CGI-58), also known as α β hydrolase domain-containing 5 (ABHD5), cause neutral lipid storage disorder with ichthyosis (NLSDI). This inborn error in metabolism is characterized by ectopic accumulation of triacylglycerols (TAG) within cytoplasmic lipid droplets in multiple cell types. Studies over the past decade have clearly demonstrated that CGI-58 is a potent regulator of TAG hydrolysis in the disease-relevant cell types. However, despite the reproducible genetic link between CGI-58 mutations and TAG storage, the molecular mechanisms by which CGI-58 regulates TAG hydrolysis are still incompletely understood. It is clear that CGI-58 can regulate TAG hydrolysis by activating the major TAG hydrolase adipose triglyceride lipase (ATGL), yet CGI-58 can also regulate lipid metabolism via mechanisms that do not involve ATGL. This review highlights recent progress made in defining the physiologic and biochemical function of CGI-58, and its broader role in energy homeostasis. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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42
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Parry SA, Woods RM, Hodson L, Hulston CJ. A Single Day of Excessive Dietary Fat Intake Reduces Whole-Body Insulin Sensitivity: The Metabolic Consequence of Binge Eating. Nutrients 2017; 9:nu9080818. [PMID: 28758920 PMCID: PMC5579612 DOI: 10.3390/nu9080818] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/14/2017] [Accepted: 07/26/2017] [Indexed: 01/08/2023] Open
Abstract
Consuming excessive amounts of energy as dietary fat for several days or weeks can impair glycemic control and reduce insulin sensitivity in healthy adults. However, individuals who demonstrate binge eating behavior overconsume for much shorter periods of time; the metabolic consequences of such behavior remain unknown. The aim of this study was to determine the effect of a single day of high-fat overfeeding on whole-body insulin sensitivity. Fifteen young, healthy adults underwent an oral glucose tolerance test before and after consuming a high-fat (68% of total energy), high-energy (78% greater than daily requirements) diet for one day. Fasting and postprandial plasma concentrations of glucose, insulin, non-esterified fatty acids, and triglyceride were measured and the Matsuda insulin sensitivity index was calculated. One day of high-fat overfeeding increased postprandial glucose area under the curve (AUC) by 17.1% (p < 0.0001) and insulin AUC by 16.4% (p = 0.007). Whole-body insulin sensitivity decreased by 28% (p = 0.001). In conclusion, a single day of high-fat, overfeeding impaired whole-body insulin sensitivity in young, healthy adults. This highlights the rapidity with which excessive consumption of calories through high-fat food can impair glucose metabolism, and suggests that acute binge eating may have immediate metabolic health consequences for the individual.
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Affiliation(s)
- Siôn A Parry
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
| | - Rachel M Woods
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK.
| | - Carl J Hulston
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
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Benítez-Santana T, Hugo SE, Schlegel A. Role of Intestinal LXRα in Regulating Post-prandial Lipid Excursion and Diet-Induced Hypercholesterolemia and Hepatic Lipid Accumulation. Front Physiol 2017; 8:280. [PMID: 28536535 PMCID: PMC5422522 DOI: 10.3389/fphys.2017.00280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/18/2017] [Indexed: 12/12/2022] Open
Abstract
Post-prandial hyperlipidemia has emerged as a cardiovascular risk factor with limited therapeutic options. The Liver X receptors (Lxrs) are nuclear hormone receptors that regulate cholesterol elimination. Knowledge of their role in regulating the absorption and handling of dietary fats is incomplete. The purpose of this study was to determine the role of intestinal Lxrα in post-prandial intestinal lipid transport. Using Lxrα knockout (nr1h3−/−) and intestine-limited Lxrα over-expressing [Tg(fabp2a:EGFP-nr1h3)] zebrafish strains, we measured post-prandial lipid excursion with live imaging in larvae and physiological methods in adults. We also conducted a long-term high-cholesterol dietary challenge in adults to examine the chronic effect of modulating nr1h3 gene dose on the development of hypercholesterolemia and hepatic lipid accumulation. Over-expression of Lxrα in the intestine delays the transport of ingested lipids in larvae, while deletion of Lxrα increases the rate of lipid transport. Pre-treating wildtype larvae with the liver-sparing Lxr agonist hyodeoxycholic acid also delayed the rate of intestinal lipid transport in larvae. In adult males, deletion of Lxrα accelerates intestinal transport of ingested lipids. Adult females showed higher plasma Lipoprotein lipase (Lpl) activity compared to males, and lower post-gavage blood triacylglycerol (TAG) excursion. Despite the sexually dimorphic effect on acute intestinal lipid handling, Tg(fabp2a:EGFP-nr1h3) adults of both sexes are protected from high cholesterol diet (HCD)-induced hepatic lipid accumulation, while nr1h3−/− mutants are sensitive to the effects of HCD challenge. These data indicate that intestinal Lxr activity dampens the pace of intestinal lipid transport cell-autonomously. Selective activation of intestinal Lxrα holds therapeutic promise.
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Affiliation(s)
- Tibiábin Benítez-Santana
- University of Utah Molecular Medicine Program, School of Medicine, University of UtahSalt Lake City, UT, USA.,Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, School of Medicine, University of UtahSalt Lake City, UT, USA
| | - Sarah E Hugo
- University of Utah Molecular Medicine Program, School of Medicine, University of UtahSalt Lake City, UT, USA.,Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, School of Medicine, University of UtahSalt Lake City, UT, USA
| | - Amnon Schlegel
- University of Utah Molecular Medicine Program, School of Medicine, University of UtahSalt Lake City, UT, USA.,Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, School of Medicine, University of UtahSalt Lake City, UT, USA.,Department of Biochemistry, School of Medicine, University of UtahSalt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, College of Health, University of UtahSalt Lake City, UT, USA
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44
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Steenson S, Umpleby AM, Lovegrove JA, Jackson KG, Fielding BA. Role of the Enterocyte in Fructose-Induced Hypertriglyceridaemia. Nutrients 2017; 9:nu9040349. [PMID: 28368310 PMCID: PMC5409688 DOI: 10.3390/nu9040349] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/21/2017] [Accepted: 03/31/2017] [Indexed: 01/12/2023] Open
Abstract
Dietary fructose has been linked to an increased post-prandial triglyceride (TG) level; which is an established independent risk factor for cardiovascular disease. Although much research has focused on the effects of fructose consumption on liver-derived very-low density lipoprotein (VLDL); emerging evidence also suggests that fructose may raise post-prandial TG levels by affecting the metabolism of enterocytes of the small intestine. Enterocytes have become well recognised for their ability to transiently store lipids following a meal and to thus control post-prandial TG levels according to the rate of chylomicron (CM) lipoprotein synthesis and secretion. The influence of fructose consumption on several aspects of enterocyte lipid metabolism are discussed; including de novo lipogenesis; apolipoprotein B48 and CM-TG production; based on the findings of animal and human isotopic tracer studies. Methodological issues affecting the interpretation of fructose studies conducted to date are highlighted; including the accurate separation of CM and VLDL. Although the available evidence to date is limited; disruption of enterocyte lipid metabolism may make a meaningful contribution to the hypertriglyceridaemia often associated with fructose consumption.
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Affiliation(s)
- Simon Steenson
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7WG, UK.
- Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading RG6 6AP, UK.
| | - A Margot Umpleby
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7WG, UK.
| | - Julie A Lovegrove
- Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading RG6 6AP, UK.
| | - Kim G Jackson
- Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading RG6 6AP, UK.
| | - Barbara A Fielding
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7WG, UK.
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45
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Khalifeh-Soltani A, Gupta D, Ha A, Iqbal J, Hussain M, Podolsky MJ, Atabai K. Mfge8 regulates enterocyte lipid storage by promoting enterocyte triglyceride hydrolase activity. JCI Insight 2016; 1:e87418. [PMID: 27812539 DOI: 10.1172/jci.insight.87418] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The small intestine has an underappreciated role as a lipid storage organ. Under conditions of high dietary fat intake, enterocytes can minimize the extent of postprandial lipemia by storing newly absorbed dietary fat in cytoplasmic lipid droplets. Lipid droplets can be subsequently mobilized for the production of chylomicrons. The mechanisms that regulate this process are poorly understood. We report here that the milk protein Mfge8 regulates hydrolysis of cytoplasmic lipid droplets in enterocytes after interacting with the αvβ3 and αvβ5 integrins. Mice deficient in Mfge8 or the αvβ3 and αvβ5 integrins accumulate excess cytoplasmic lipid droplets after a fat challenge. Mechanistically, interruption of the Mfge8-integrin axis leads to impaired enterocyte intracellular triglyceride hydrolase activity in vitro and in vivo. Furthermore, Mfge8 increases triglyceride hydrolase activity through a PI3 kinase/mTORC2-dependent signaling pathway. These data identify a key role for Mfge8 and the αvβ3 and αvβ5 integrins in regulating enterocyte lipid processing.
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Affiliation(s)
- Amin Khalifeh-Soltani
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
| | - Deepti Gupta
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
| | - Arnold Ha
- Department of Medicine.,Cardiovascular Research Institute
| | - Jahangir Iqbal
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Mahmood Hussain
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Michael J Podolsky
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
| | - Kamran Atabai
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
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46
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McFie PJ, Izzard S, Vu H, Jin Y, Beauchamp E, Berthiaume LG, Stone SJ. Membrane topology of human monoacylglycerol acyltransferase-2 and identification of regions important for its localization to the endoplasmic reticulum. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1192-1204. [PMID: 27373844 DOI: 10.1016/j.bbalip.2016.06.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 11/16/2022]
Abstract
Acyl CoA:2-monoacylglycerol acyltransferase (MGAT)-2 has an important role in dietary fat absorption in the intestine. MGAT2 resides in the endoplasmic reticulum and catalyzes the synthesis of diacylglycerol which is then utilized as a substrate for triacylglycerol synthesis. This triacylglycerol is then incorporated into chylomicrons which are released into the circulation. In this study, we determined the membrane topology of human MGAT2. Protease protection experiments showed that the C-terminus is exposed to the cytosol, while the N-terminus is partially buried in the ER membrane. MGAT2, like murine DGAT2, was found to have two transmembrane domains. We also identified a region of MGAT2 associated with the ER membrane that contains the histidine-proline-histidine-glycine sequence present in all DGAT2 family members that is thought to comprise the active site. Proteolysis experiments demonstrated that digestion of total cellular membranes from cells expressing MGAT2 with trypsin abolished MGAT activity, indicating that domains that are important for catalysis face the cytosol. We also explored the role that the five cysteines residues present in MGAT2 have in catalysis. MGAT activity was sensitive to two thiol modifiers, N-ethylmaleimide and 5,5'-dithiobis-(2-nitrobenzoic acid). Furthermore, mutation of four cysteines resulted in a reduction in MGAT activity. However, when the C-terminal cysteine (C334) was mutated, MGAT activity was actually higher than that of wild-type FL-MGAT2. Lastly, we determined that both transmembrane domains of MGAT2 are important for its ER localization, and that MGAT2 is present in mitochondrial-associated membranes.
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Affiliation(s)
- Pamela J McFie
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Sabrina Izzard
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Huyen Vu
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Youzhi Jin
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Erwan Beauchamp
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Luc G Berthiaume
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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47
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Yue S, Cheng JX. Deciphering single cell metabolism by coherent Raman scattering microscopy. Curr Opin Chem Biol 2016; 33:46-57. [PMID: 27288951 DOI: 10.1016/j.cbpa.2016.05.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/18/2016] [Indexed: 11/20/2022]
Abstract
Metabolism is highly dynamic and intrinsically heterogeneous at the cellular level. Although fluorescence microscopy has been commonly used for single cell analysis, bulky fluorescent probes often perturb the biological activities of small biomolecules such as metabolites. Such challenge can be overcome by a vibrational imaging technique known as coherent Raman scattering microscopy, which is capable of chemically selective, highly sensitive, and high-speed imaging of biomolecules with submicron resolution. Such capability has enabled quantitative assessments of metabolic activities of biomolecules (e.g. lipids, proteins, nucleic acids) in single live cells in vitro and in vivo. These investigations provide new insights into the role of cell metabolism in maintenance of homeostasis and pathogenesis of diseases.
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Affiliation(s)
- Shuhua Yue
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, PR China.
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Department of Chemistry, Purdue University Center for Cancer Research, Birck Nanotechnology Center, Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA.
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48
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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: 88] [Impact Index Per Article: 11.0] [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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49
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Hepatic insulin resistance both in prediabetic and diabetic patients determines postprandial lipoprotein metabolism: from the CORDIOPREV study. Cardiovasc Diabetol 2016; 15:68. [PMID: 27095446 PMCID: PMC4837552 DOI: 10.1186/s12933-016-0380-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/30/2016] [Indexed: 11/10/2022] Open
Abstract
Background/aims Previous evidences have shown the presence of a prolonged and exaggerated postprandial response in type 2 diabetes mellitus (T2DM) and its relation with an increase of cardiovascular risk. However, the response in prediabetes population has not been established. The objective was to analyze the degree of postprandial lipemia response in the CORDIOPREV clinical trial (NCT00924937) according to the diabetic status. Methods 1002 patients were submitted to an oral fat load test meal (OFTT) with 0.7 g fat/kg body weight [12 % saturated fatty acids (SFA), 10 % polyunsaturated fatty acids (PUFA), 43 % monounsaturated fatty acids (MUFA), 10 % protein and 25 % carbohydrates]. Serial blood test analyzing lipid fractions were drawn at 0, 1, 2, 3 and 4 h during postprandial state. Postprandial triglycerides (TG) concentration at any point >2.5 mmol/L (220 mg/dL) has been established as undesirable response. We explored the dynamic response in 57 non-diabetic, 364 prediabetic and 581 type 2 diabetic patients. Additionally, the postprandial response was evaluated according to basal insulin resistance subgroups in patients non-diabetic and diabetic without pharmacological treatment (N = 642). Results Prevalence of undesirable postprandial TG was 35 % in non-diabetic, 48 % in prediabetic and 59 % in diabetic subgroup, respectively (p < 0.001). Interestingly, prediabetic patients displayed higher plasma TG and large triacylglycerol-rich lipoproteins (TRLs-TG) postprandial response compared with those non-diabetic patients (p < 0.001 and p = 0.003 respectively). Moreover, the area under the curve (AUC) of TG and AUC of TRLs-TG was greater in the prediabetic group compared with non-diabetic patients (p < 0.001 and p < 0.005 respectively). Patients with liver insulin resistance (liver-IR) showed higher postprandial response of TG compared with those patients with muscle-IR or without any insulin-resistance respectively (p < 0.001). Conclusions Our findings demonstrate that prediabetic patients show a lower phenotypic flexibility after external aggression, such as OFTT compared with nondiabetic patients. The postprandial response increases progressively according to non-diabetic, prediabetic and type 2 diabetic state and it is higher in patients with liver insulin-resistance. To identify this subgroup of patients is important to treat more intensively in order to avoid future cardiometabolic complications.
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50
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Briand O, Touche V, Colin S, Brufau G, Davalos A, Schonewille M, Bovenga F, Carrière V, de Boer JF, Dugardin C, Riveau B, Clavey V, Tailleux A, Moschetta A, Lasunción MA, Groen AK, Staels B, Lestavel S. Liver X Receptor Regulates Triglyceride Absorption Through Intestinal Down-regulation of Scavenger Receptor Class B, Type 1. Gastroenterology 2016; 150:650-8. [PMID: 26602218 DOI: 10.1053/j.gastro.2015.11.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 10/30/2015] [Accepted: 11/10/2015] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Reducing postprandial triglyceridemia may be a promising strategy to lower the risk of cardiovascular disorders associated with obesity and type 2 diabetes. In enterocytes, scavenger receptor class B, type 1 (SR-B1, encoded by SCARB1) mediates lipid-micelle sensing to promote assembly and secretion of chylomicrons. The nuclear receptor subfamily 1, group H, members 2 and 3 (also known as liver X receptors [LXRs]) regulate genes involved in cholesterol and fatty acid metabolism. We aimed to determine whether intestinal LXRs regulate triglyceride absorption. METHODS C57BL/6J mice were either fed a cholesterol-enriched diet or given synthetic LXR agonists (GW3965 or T0901317). We measured the production of chylomicrons and localized SR-B1 by immunohistochemistry. Mechanisms of postprandial triglyceridemia and SR-B1 regulation were studied in Caco-2/TC7 cells incubated with LXR agonists. RESULTS In mice and in the Caco-2/TC7 cell line, LXR agonists caused localization of intestinal SR-B1 from apical membranes to intracellular organelles and reduced chylomicron secretion. In Caco-2/TC7 cells, LXR agonists reduced SR-B1-dependent lipidic-micelle-induced Erk phosphorylation. LXR agonists also reduced intracellular trafficking of the apical apolipoprotein B pool toward secretory compartments. LXR reduced levels of SR-B1 in Caco-2/TC7 cells via a post-transcriptional mechanism that involves microRNAs. CONCLUSION In Caco-2/TC7 cells and mice, intestinal activation of LXR reduces the production of chylomicrons by a mechanism dependent on the apical localization of SR-B1.
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Affiliation(s)
- Olivier Briand
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Véronique Touche
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Sophie Colin
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Gemma Brufau
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Alberto Davalos
- Madrid Institute for Advanced Studies (IMDEA) Food Institute, Laboratory of Disorders of Lipid Metabolism and Molecular Nutrition, Campus de Excelencia Internacional (CEI), Universidad Autónoma de Madrid (UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Marleen Schonewille
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Fabiola Bovenga
- National Research Cancer Center, Giovanni Paolo II, and University of Bari, Bari, Italy
| | - Véronique Carrière
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes, Sorbonne Paris Cit, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France; Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigatión Sanitaria (IRYCIS), Madrid, Spain
| | - Jan Freark de Boer
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Camille Dugardin
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Béatrice Riveau
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC), UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France; Institut National de la Santé et de la Recherche Médicale (INSERM), UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes, Sorbonne Paris Cit, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
| | - Véronique Clavey
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Anne Tailleux
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Antonio Moschetta
- National Research Cancer Center, Giovanni Paolo II, and University of Bari, Bari, Italy
| | - Miguel A Lasunción
- Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigatión Sanitaria (IRYCIS), Madrid, Spain; Centro de Investigatión Biomedica en Red (CIBER) de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Spain
| | - Albert K Groen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Bart Staels
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France.
| | - Sophie Lestavel
- University Lille, Inserm, Centre Hospitalier Universitaire (CHU) de Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
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