1
|
Zhang N, Wang H, Ran S, Wang Z, Zhou B, Wang S, Li Z, Liu B, Nie Y, Huang Y, Meng H. Mutations in the leptin-melanocortin pathway and weight loss after bariatric surgery: a systematic review and meta-analysis. Obesity (Silver Spring) 2024; 32:1047-1058. [PMID: 38577709 DOI: 10.1002/oby.24007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/31/2023] [Accepted: 01/03/2024] [Indexed: 04/06/2024]
Abstract
OBJECTIVE The objective of this meta-analysis was to quantify the overall effects of gene mutations in the leptin-melanocortin pathway on short- and long-term weight loss after bariatric surgery. METHODS MEDLINE, PubMed, and Embase were searched, and data were analyzed using ReviewManager (RevMan) version 5.4. The datasets were divided into two subgroups based on postoperative time, and the outcome measure was the percentage of total weight loss. Meta-regression analysis was performed, and the outcome was presented as the weighed mean difference of percentage of total weight loss. RESULTS The results showed that patients with mutations in the leptin-melanocortin pathway experienced 3.03% lower total weight loss after bariatric surgery (mean difference, -3.03; 95% CI: -3.63 to -2.44), mainly reflected in lower long-term postoperative weight loss (mean difference, -3.43; 95% CI: -4.09 to -2.77), whereas mutation carriers exhibited a magnitude of short-term postoperative weight loss that was similar to patients without such mutations (total difference value, -1.13; 95% CI: -2.57 to 0.31). CONCLUSIONS Mutations in leptin-melanocortin pathway genes reduce long-term weight loss after bariatric surgery, whereas this effect may not be reflected during the period of rapid weight loss within 12 months. These genetic variants increase the difficulties in maintaining patients' long-term weight loss.
Collapse
Affiliation(s)
- Nianrong Zhang
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Hao Wang
- Xiangya School of Medicine, Central South University, Changsha, China
| | - Shuman Ran
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Zhe Wang
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Biao Zhou
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Siqi Wang
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Zhengqi Li
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Baoyin Liu
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Yuntao Nie
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Yishan Huang
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| | - Hua Meng
- General Surgery Department & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, China
| |
Collapse
|
2
|
Wei R, Li D, Jia S, Chen Y, Wang J. MC4R in Central and Peripheral Systems. Adv Biol (Weinh) 2023; 7:e2300035. [PMID: 37043700 DOI: 10.1002/adbi.202300035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/25/2023] [Indexed: 04/14/2023]
Abstract
Obesity has emerged as a critical and urgent health burden during the current global pandemic. Among multiple genetic causes, melanocortin receptor-4 (MC4R), involved in food intake and energy metabolism regulation through various signaling pathways, has been reported to be the lead genetic factor in severe and early onset obesity and hyperphagia disorders. Most previous studies have illustrated the roles of MC4R signaling in energy intake versus expenditure in the central system, while some evidence indicates that MC4R is also expressed in peripheral systems, such as the gut and endocrine organs. However, its physiopathological function remains poorly defined. This review aims to depict the central and peripheral roles of MC4R in energy metabolism and endocrine hormone homeostasis, the diversity of phenotypes, biased downstream signaling caused by distinct MC4R mutations, and current drug development targeting the receptor.
Collapse
Affiliation(s)
- Ran Wei
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
- Department of Endocrinology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, 200240, China
| | - Danjie Li
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Sheng Jia
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Yuhong Chen
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Jiqiu Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| |
Collapse
|
3
|
Signaling pathways in obesity: mechanisms and therapeutic interventions. Signal Transduct Target Ther 2022; 7:298. [PMID: 36031641 PMCID: PMC9420733 DOI: 10.1038/s41392-022-01149-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/26/2022] [Accepted: 08/08/2022] [Indexed: 12/19/2022] Open
Abstract
Obesity is a complex, chronic disease and global public health challenge. Characterized by excessive fat accumulation in the body, obesity sharply increases the risk of several diseases, such as type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease, and is linked to lower life expectancy. Although lifestyle intervention (diet and exercise) has remarkable effects on weight management, achieving long-term success at weight loss is extremely challenging, and the prevalence of obesity continues to rise worldwide. Over the past decades, the pathophysiology of obesity has been extensively investigated, and an increasing number of signal transduction pathways have been implicated in obesity, making it possible to fight obesity in a more effective and precise way. In this review, we summarize recent advances in the pathogenesis of obesity from both experimental and clinical studies, focusing on signaling pathways and their roles in the regulation of food intake, glucose homeostasis, adipogenesis, thermogenesis, and chronic inflammation. We also discuss the current anti-obesity drugs, as well as weight loss compounds in clinical trials, that target these signals. The evolving knowledge of signaling transduction may shed light on the future direction of obesity research, as we move into a new era of precision medicine.
Collapse
|
4
|
Stahel P, Xiao C, Nahmias A, Tian L, Lewis GF. Multi-organ Coordination of Lipoprotein Secretion by Hormones, Nutrients and Neural Networks. Endocr Rev 2021; 42:815-838. [PMID: 33743013 PMCID: PMC8599201 DOI: 10.1210/endrev/bnab008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 12/15/2022]
Abstract
Plasma triglyceride-rich lipoproteins (TRL), particularly atherogenic remnant lipoproteins, contribute to atherosclerotic cardiovascular disease. Hypertriglyceridemia may arise in part from hypersecretion of TRLs by the liver and intestine. Here we focus on the complex network of hormonal, nutritional, and neuronal interorgan communication that regulates secretion of TRLs and provide our perspective on the relative importance of these factors. Hormones and peptides originating from the pancreas (insulin, glucagon), gut [glucagon-like peptide 1 (GLP-1) and 2 (GLP-2), ghrelin, cholecystokinin (CCK), peptide YY], adipose tissue (leptin, adiponectin) and brain (GLP-1) modulate TRL secretion by receptor-mediated responses and indirectly via neural networks. In addition, the gut microbiome and bile acids influence lipoprotein secretion in humans and animal models. Several nutritional factors modulate hepatic lipoprotein secretion through effects on the central nervous system. Vagal afferent signaling from the gut to the brain and efferent signals from the brain to the liver and gut are modulated by hormonal and nutritional factors to influence TRL secretion. Some of these factors have been extensively studied and shown to have robust regulatory effects whereas others are "emerging" regulators, whose significance remains to be determined. The quantitative importance of these factors relative to one another and relative to the key regulatory role of lipid availability remains largely unknown. Our understanding of the complex interorgan regulation of TRL secretion is rapidly evolving to appreciate the extensive hormonal, nutritional, and neural signals emanating not only from gut and liver but also from the brain, pancreas, and adipose tissue.
Collapse
Affiliation(s)
- Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & 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
| | - Avital Nahmias
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Lili Tian
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Gary Franklin Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
5
|
Neuro-immune-metabolism: The tripod system of homeostasis. Immunol Lett 2021; 240:77-97. [PMID: 34655659 DOI: 10.1016/j.imlet.2021.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 11/20/2022]
Abstract
Homeostatic regulation of cellular and molecular processes is essential for the efficient physiological functioning of body organs. It requires an intricate balance of several networks throughout the body, most notable being the nervous, immune and metabolic systems. Several studies have reported the interactions between neuro-immune, immune-metabolic and neuro-metabolic pathways. Current review aims to integrate the information and show that neuro, immune and metabolic systems form the triumvirate of homeostasis. It focuses on the cellular and molecular interactions occurring in the extremities and intestine, which are innervated by the peripheral nervous system and for the intestine in particular the enteric nervous system. While the interdependence of neuro-immune-metabolic pathways provides a fallback mechanism in case of disruption of homeostasis, in chronic pathologies of continued disequilibrium, the collapse of one system spreads to the other interacting networks as well. Current review illustrates this domino-effect using diabetes as the main example. Together, this review attempts to provide a holistic picture of the integrated network of neuro-immune-metabolism and attempts to broaden the outlook when devising a scientific study or a treatment strategy.
Collapse
|
6
|
Aravani D, Kassi E, Chatzigeorgiou A, Vakrou S. Cardiometabolic Syndrome: An Update on Available Mouse Models. Thromb Haemost 2020; 121:703-715. [PMID: 33280078 DOI: 10.1055/s-0040-1721388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cardiometabolic syndrome (CMS), a disease entity characterized by abdominal obesity, insulin resistance (IR), hypertension, and hyperlipidemia, is a global epidemic with approximately 25% prevalence in adults globally. CMS is associated with increased risk for cardiovascular disease (CVD) and development of diabetes. Due to its multifactorial etiology, the development of several animal models to simulate CMS has contributed significantly to the elucidation of the disease pathophysiology and the design of therapies. In this review we aimed to present the most common mouse models used in the research of CMS. We found that CMS can be induced either by genetic manipulation, leading to dyslipidemia, lipodystrophy, obesity and IR, or obesity and hypertension, or by administration of specific diets and drugs. In the last decade, the ob/ob and db/db mice were the most common obesity and IR models, whereas Ldlr-/- and Apoe-/- were widely used to induce hyperlipidemia. These mice have been used either as a single transgenic or combined with a different background with or without diet treatment. High-fat diet with modifications is the preferred protocol, generally leading to increased body weight, hyperlipidemia, and IR. A plethora of genetically engineered mouse models, diets, drugs, or synthetic compounds that are available have advanced the understanding of CMS. However, each researcher should carefully select the most appropriate model and validate its consistency. It is important to consider the differences between strains of the same animal species, different animals, and most importantly differences to human when translating results.
Collapse
Affiliation(s)
- Dimitra Aravani
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eva Kassi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Antonios Chatzigeorgiou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,Institute for Clinical Chemistry and Laboratory Medicine, University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Dresden, Germany
| | - Styliani Vakrou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,Department of Cardiology, "Laiko" General Hospital, Athens, Greece
| |
Collapse
|
7
|
Iqbal J, Mascareno E, Chua S, Hussain MM. Leptin-mediated differential regulation of microsomal triglyceride transfer protein in the intestine and liver affects plasma lipids. J Biol Chem 2020; 295:4101-4113. [PMID: 32047110 PMCID: PMC7105304 DOI: 10.1074/jbc.ra119.011881] [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] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/06/2020] [Indexed: 11/06/2022] Open
Abstract
The hormone leptin regulates fat storage and metabolism by signaling through the brain and peripheral tissues. Lipids delivered to peripheral tissues originate mostly from the intestine and liver via synthesis and secretion of apolipoprotein B (apoB)-containing lipoproteins. An intracellular chaperone, microsomal triglyceride transfer protein (MTP), is required for the biosynthesis of these lipoproteins, and its regulation determines fat mobilization to different tissues. Using cell culture and animal models, here we sought to identify the effects of leptin on MTP expression in the intestine and liver. Leptin decreased MTP expression in differentiated intestinal Caco-2 cells, but increased expression in hepatic Huh7 cells. Similarly, acute and chronic leptin treatment of chow diet-fed WT mice decreased MTP expression in the intestine, increased it in the liver, and lowered plasma triglyceride levels. These leptin effects required the presence of leptin receptors (LEPRs). Further experiments also suggested that leptin interacted with long-form LEPR (ObRb), highly expressed in the intestine, to down-regulate MTP. In contrast, in the liver, leptin interacted with short-form LEPR (ObRa) to increase MTP expression. Mechanistic experiments disclosed that leptin activates signal transducer and activator of transcription 3 (STAT3) and mitogen-activated protein kinase (MAPK) signaling pathways in intestinal and hepatic cells, respectively, and thereby regulates divergent MTP expression. Our results also indicated that leptin-mediated MTP regulation in the intestine affects plasma lipid levels. In summary, our findings suggest that leptin regulates MTP expression differentially by engaging with different LEPR types and activating distinct signaling pathways in intestinal and hepatic cells.
Collapse
Affiliation(s)
- Jahangir Iqbal
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203; King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, Eastern Region, Ministry of National Guard Health Affairs, Al Ahsa 31982, Saudi Arabia.
| | - Eduardo Mascareno
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203
| | - Streamson Chua
- Department of Medicine and Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461
| | - M Mahmood Hussain
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203; Department of Foundations of Medicine, NYU Long Island School of Medicine and Diabetes and Obesity Research Center, NYU Winthrop Research Institute, Mineola, New York 11501; Veterans Affairs New York Harbor Healthcare System, Brooklyn, New York 11209.
| |
Collapse
|
8
|
Stahel P, Xiao C, Nahmias A, Lewis GF. Role of the Gut in Diabetic Dyslipidemia. Front Endocrinol (Lausanne) 2020; 11:116. [PMID: 32231641 PMCID: PMC7083132 DOI: 10.3389/fendo.2020.00116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/21/2020] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes (T2D) is associated with increased risk of cardiovascular disease (CVD). In insulin resistant states such as the metabolic syndrome, overproduction and impaired clearance of liver-derived very-low-density lipoproteins and gut-derived chylomicrons (CMs) contribute to hypertriglyceridemia and elevated atherogenic remnant lipoproteins. Although ingested fat is the major stimulus of CM secretion, intestinal lipid handling and ultimately CM secretory rate is determined by numerous additional regulatory inputs including nutrients, hormones and neural signals that fine tune CM secretion during fasted and fed states. Insulin resistance and T2D represent perturbed metabolic states in which intestinal sensitivity to key regulatory hormones such as insulin, leptin and glucagon-like peptide-1 (GLP-1) may be altered, contributing to increased CM secretion. In this review, we describe the evidence from human and animal models demonstrating increased CM secretion in insulin resistance and T2D and discuss the molecular mechanisms underlying these effects. Several novel compounds are in various stages of preclinical and clinical investigation to modulate intestinal CM synthesis and secretion. Their efficacy, safety and therapeutic utility are discussed. Similarly, the effects of currently approved lipid modulating therapies such as statins, ezetimibe, fibrates, and PCSK9 inhibitors on intestinal CM production are discussed. The intricacies of intestinal CM production are an active area of research that may yield novel therapies to prevent atherosclerotic CVD in insulin resistance and T2D.
Collapse
|
9
|
Iqbal J, Jahangir Z, Al-Qarni AA. Microsomal Triglyceride Transfer Protein: From Lipid Metabolism to Metabolic Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:37-52. [DOI: 10.1007/978-981-15-6082-8_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
10
|
Pereira S, O'Dwyer SM, Webber TD, Baker RK, So V, Ellis CE, Yoon JS, Mojibian M, Glavas MM, Karunakaran S, Clee SM, Covey SD, Kieffer TJ. Metabolic effects of leptin receptor knockdown or reconstitution in adipose tissues. Sci Rep 2019; 9:3307. [PMID: 30824713 PMCID: PMC6397253 DOI: 10.1038/s41598-019-39498-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 12/31/2018] [Indexed: 01/26/2023] Open
Abstract
The relative contribution of peripheral and central leptin signalling to the regulation of metabolism and the mechanisms through which leptin affects glucose homeostasis have not been fully elucidated. We generated complementary lines of mice with either leptin receptor (Lepr) knockdown or reconstitution in adipose tissues using Cre-lox methodology. Lepr knockdown mice were modestly lighter and had lower plasma insulin concentrations following an oral glucose challenge compared to controls, despite similar insulin sensitivity. We rendered male mice diabetic using streptozotocin (STZ) and found that upon prolonged leptin therapy, Lepr knockdown mice had an accelerated decrease in blood glucose compared to controls that was associated with higher plasma concentrations of leptin and leptin receptor. Mice with transcriptional blockade of Lepr (LeprloxTB/loxTB) were obese and hyperglycemic and reconstitution of Lepr in adipose tissues of LeprloxTB/loxTB mice resulted in males reaching a higher maximal body weight. Although mice with adipose tissue Lepr reconstitution had lower blood glucose levels at several ages, their plasma insulin concentrations during an oral glucose test were elevated. Thus, attenuation or restoration of Lepr in adipocytes alters the plasma insulin profile following glucose ingestion, modifies the glucose-lowering effect of prolonged leptin therapy in insulin-deficient diabetes, and may modulate weight gain.
Collapse
Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Shannon M O'Dwyer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Travis D Webber
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Robert K Baker
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Victor So
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Cara E Ellis
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Ji Soo Yoon
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Majid Mojibian
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Subashini Karunakaran
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Susanne M Clee
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada. .,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
| |
Collapse
|
11
|
Di Filippo M, Varret M, Boehm V, Rabès JP, Ferkdadji L, Abramowitz L, Dumont S, Lenaerts C, Boileau C, Joly F, Schmitz J, Samson-Bouma ME, Bonnefont-Rousselot D. Postprandial lipid absorption in seven heterozygous carriers of deleterious variants of MTTP in two abetalipoproteinemic families. J Clin Lipidol 2018; 13:201-212. [PMID: 30522860 DOI: 10.1016/j.jacl.2018.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/25/2018] [Accepted: 10/12/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Abetalipoproteinemia, a recessive disease resulting from deleterious variants in MTTP (microsomal triglyceride transfer protein), is characterized by undetectable concentrations of apolipoprotein B, extremely low levels of low-density lipoprotein cholesterol in the plasma, and a total inability to export apolipoprotein B-containing lipoproteins from both the intestine and the liver. OBJECTIVE To study lipid absorption after a fat load and liver function in 7 heterozygous relatives from 2 abetalipoproteinemic families, 1 previously unreported. RESULTS Both patients are compound heterozygotes for p.(Arg540His) and either c.708_709del p.(His236Glnfs*11) or c.1344+3_1344+6del on the MTTP gene. The previously undescribed patient has been followed for 22 years with ultrastructure analyses of both the intestine and the liver. In these 2 families, 5 relatives were heterozygous for p.(Arg540His), 1 for p.(His236Glnfs*11) and 1 for c.1344+3_1344+6del. In 4 heterozygous relatives, the lipid absorption was normal independent of the MTTP variant. In contrast, in 3 of them, the increase in triglyceride levels after fat load was abnormal. These subjects were additionally heterozygous carriers of Asp2213 APOB in-frame deletion, near the cytidine mRNA editing site, which is essential for intestinal apoB48 production. Liver function appeared to be normal in all the heterozygotes except for one who exhibited liver steatosis for unexplained reasons. CONCLUSION Our study suggests that a single copy of the MTTP gene may be sufficient for human normal lipid absorption, except when associated with an additional APOB gene alteration. The hepatic steatosis reported in 1 patient emphasizes the need for liver function tests in all heterozygotes until the level of risk is established.
Collapse
Affiliation(s)
- Mathilde Di Filippo
- UF Dyslipidemies, Service de Biochimie et Biologie moléculaire Grand Est, GHE, Hospices Civils de Lyon, Bron Cedex, France; Univ-Lyon, CarMeN laboratory, Inserm U1060, INRA U1397, Université Claude Bernard Lyon 1, INSA Lyon, Villeurbanne, France.
| | - Mathilde Varret
- INSERM U1148, Université Paris Diderot, Hôpital Bichat-Claude Bernard, Paris Cedex 18, France
| | - Vanessa Boehm
- Service de gastroentérologie, MICI et Assistance Nutritive, Hopital Beaujon, Hopital Beaujon (AP-HP), Université Paris VII, Paris, France. INSERM UMR1149, Centre de Recherche sur l'Inflammation Paris Montmartre (CRI), Paris, France
| | - Jean-Pierre Rabès
- INSERM U1148, Université Paris Diderot, Hôpital Bichat-Claude Bernard, Paris Cedex 18, France; AP-HP, HUPIFO, Hôpital Ambroise Paré, Laboratoire de Biochimie et Génétique Moléculaire & UVSQ, UFR des Sciences de la Santé Simone Veil, Montigny-Le-Bretonneux, France
| | - Latifa Ferkdadji
- Service d'anatomie et de cytologie pathologiques, Hôpital Robert Debré, Université Paris 7, Paris, France
| | - Laurent Abramowitz
- Service d'Hépato-Gastroentérologie, Hôpital Bichat-Claude Bernard, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris Cedex 18, France
| | - Sabrina Dumont
- UF Dyslipidemies, Service de Biochimie et Biologie moléculaire Grand Est, GHE, Hospices Civils de Lyon, Bron Cedex, France
| | | | - Catherine Boileau
- INSERM U1148, Université Paris Diderot, Hôpital Bichat-Claude Bernard, Paris Cedex 18, France
| | - Francisca Joly
- Service de gastroentérologie, MICI et Assistance Nutritive, Hopital Beaujon, Hopital Beaujon (AP-HP), Université Paris VII, Paris, France. INSERM UMR1149, Centre de Recherche sur l'Inflammation Paris Montmartre (CRI), Paris, France
| | - Jacques Schmitz
- Département de Gastroentérologie pédiatrique, Hopital Necker-Enfants Malades, Paris, France
| | | | - Dominique Bonnefont-Rousselot
- Service de Biochimie métabolique, Hôpitaux universitaires Pitié-Salpêtrière-Charles Foix (AP-HP), Paris, France; Faculté de Pharmacie de Paris, Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, U 1022 INSERM, UMR 8258 CNRS, Paris, France
| |
Collapse
|
12
|
System-wide Benefits of Intermeal Fasting by Autophagy. Cell Metab 2017; 26:856-871.e5. [PMID: 29107505 PMCID: PMC5718973 DOI: 10.1016/j.cmet.2017.09.020] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 06/28/2017] [Accepted: 09/25/2017] [Indexed: 12/13/2022]
Abstract
Autophagy failure is associated with metabolic insufficiency. Although caloric restriction (CR) extends healthspan, its adherence in humans is poor. We established an isocaloric twice-a-day (ITAD) feeding model wherein ITAD-fed mice consume the same food amount as ad libitum controls but at two short windows early and late in the diurnal cycle. We hypothesized that ITAD feeding will provide two intervals of intermeal fasting per circadian period and induce autophagy. We show that ITAD feeding modifies circadian autophagy and glucose/lipid metabolism that correlate with feeding-driven changes in circulating insulin. ITAD feeding decreases adiposity and, unlike CR, enhances muscle mass. ITAD feeding drives energy expenditure, lowers lipid levels, suppresses gluconeogenesis, and prevents age/obesity-associated metabolic defects. Using liver-, adipose-, myogenic-, and proopiomelanocortin neuron-specific autophagy-null mice, we mapped the contribution of tissue-specific autophagy to system-wide benefits of ITAD feeding. Our studies suggest that consuming two meals a day without CR could prevent the metabolic syndrome.
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
Hsieh J, Trajcevski KE, Farr SL, Baker CL, Lake EJ, Taher J, Iqbal J, Hussain MM, Adeli K. Glucagon-Like Peptide 2 (GLP-2) Stimulates Postprandial Chylomicron Production and Postabsorptive Release of Intestinal Triglyceride Storage Pools via Induction of Nitric Oxide Signaling in Male Hamsters and Mice. Endocrinology 2015; 156:3538-47. [PMID: 26132919 DOI: 10.1210/en.2015-1110] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The intestinal overproduction of apolipoprotein B48 (apoB48)-containing chylomicron particles is a common feature of diabetic dyslipidemia and contributes to cardiovascular risk in insulin resistant states. We previously reported that glucagon-like peptide-2 (GLP-2) is a key endocrine stimulator of enterocyte fat absorption and chylomicron output in the postprandial state. GLP-2's stimulatory effect on chylomicron production in the postabsorptive state has been confirmed in human studies. The mechanism by which GLP-2 regulates chylomicron production is unclear, because its receptor is not expressed on enterocytes. We provide evidence for a key role of nitric oxide (NO) in mediating the stimulatory effects of GLP-2 during the postprandial and postabsorptive periods. Intestinal chylomicron production was assessed in GLP-2-treated hamsters administered the pan-specific NO synthase (NOS) inhibitor L-N(G)-nitroarginine methyl ester (L-NAME), and in GLP-2-treated endothelial NOS knockout mice. L-NAME blocked GLP-2-stimulated apoB48 secretion and reduced triglycerides (TGs) in the TG-rich lipoprotein (TRL) fraction of the plasma in the postprandial state. Endothelial NOS-deficient mice were resistant to GLP-2 stimulation and secreted fewer large apoB48-particles. When TG storage pools were allowed to accumulate, L-NAME mitigated the GLP-2-mediated increase in TRL-TG, suggesting that NO is required for early mobilization and secretion of stored TG and preformed chylomicrons. Importantly, the NO donor S-nitroso-L-glutathione was able to elicit an increase in TRL-TG in vivo and stimulate chylomicron release in vitro in primary enterocytes. We describe a novel role for GLP-2-mediated NO-signaling as a critical regulator of intestinal lipid handling and a potential contributor to postprandial dyslipidemia.
Collapse
Affiliation(s)
- Joanne Hsieh
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Karin E Trajcevski
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Sarah L Farr
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Christopher L Baker
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Elizabeth J Lake
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Jennifer Taher
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Jahangir Iqbal
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Mahmood M Hussain
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Khosrow Adeli
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| |
Collapse
|
15
|
Iqbal J, Walsh MT, Hammad SM, Cuchel M, Tarugi P, Hegele RA, Davidson NO, Rader DJ, Klein RL, Hussain MM. Microsomal Triglyceride Transfer Protein Transfers and Determines Plasma Concentrations of Ceramide and Sphingomyelin but Not Glycosylceramide. J Biol Chem 2015; 290:25863-75. [PMID: 26350457 DOI: 10.1074/jbc.m115.659110] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Indexed: 11/06/2022] Open
Abstract
Sphingolipids, a large family of bioactive lipids, are implicated in stress responses, differentiation, proliferation, apoptosis, and other physiological processes. Aberrant plasma levels of sphingolipids contribute to metabolic disease, atherosclerosis, and insulin resistance. They are fairly evenly distributed in high density and apoB-containing lipoproteins (B-lps). Mechanisms involved in the transport of sphingolipids to the plasma are unknown. Here, we investigated the role of microsomal triglyceride transfer protein (MTP), required for B-lp assembly and secretion, in sphingolipid transport to the plasma. Abetalipoproteinemia patients with deleterious mutations in MTP and absence of B-lps had significantly lower plasma ceramide and sphingomyelin but normal hexosylceramide, lactosylceramide, and different sphingosines compared with unaffected controls. Furthermore, similar differential effects on plasma sphingolipids were seen in liver- and intestine-specific MTP knock-out (L,I-Mttp(-/-)) mice, suggesting that MTP specifically plays a role in the regulation of plasma ceramide and sphingomyelin. We hypothesized that MTP deficiency may affect either their synthesis or secretion. MTP deficiency had no effect on ceramide and sphingomyelin synthesis but reduced secretion from primary hepatocytes and hepatoma cells. Therefore, MTP is involved in ceramide and sphingomyelin secretion but not in their synthesis. We also found that MTP transferred these lipids between vesicles in vitro. Therefore, we propose that MTP might regulate plasma ceramide and sphingomyelin levels by transferring these lipids to B-lps in the liver and intestine and facilitating their secretion.
Collapse
Affiliation(s)
| | | | - Samar M Hammad
- the Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Marina Cuchel
- the Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Patrizia Tarugi
- the Department of Life Sciences, University of Modena and Reggio Emilia, 41121 Modena, Italy
| | - Robert A Hegele
- the Blackburn Cardiovascular Genetics Laboratory, The Robarts Research Institute, London, Ontario N6A 5B7, Canada
| | - Nicholas O Davidson
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Daniel J Rader
- the Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Richard L Klein
- the Department of Medicine, Division of Endocrinology, Metabolism, and Medical Genetics, Medical University of South Carolina, Charleston, South Carolina 29425, the Research Service, Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, South Carolina 29401, and
| | - M Mahmood Hussain
- From the Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, New York 11203, the Department of Veterans Affairs New York Harbor Healthcare System, Brooklyn, New York 11209
| |
Collapse
|
16
|
Gong Z, Su K, Cui L, Tas E, Zhang T, Dong HH, Yakar S, Muzumdar RH. Central effects of humanin on hepatic triglyceride secretion. Am J Physiol Endocrinol Metab 2015; 309:E283-92. [PMID: 26058861 PMCID: PMC4525112 DOI: 10.1152/ajpendo.00043.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 06/04/2015] [Indexed: 02/06/2023]
Abstract
Humanin (HN) is an endogenous mitochondria-associated peptide that has been shown to protect against various Alzheimer's disease-associated insults, myocardial ischemia-reperfusion injury, and reactive oxygen species-induced cell death. We have shown previously that HN improves whole body glucose homeostasis by improving insulin sensitivity and increasing glucose-stimulated insulin secretion (GSIS) from the β-cells. Here, we report that intraperitoneal treatment with one of HN analogs, HNG, decreases body weight gain, visceral fat, and hepatic triglyceride (TG) accumulation in high-fat diet-fed mice. The decrease in hepatic TG accumulation is due to increased activity of hepatic microsomal triglyceride transfer protein (MTTP) and increased hepatic TG secretion. Both intravenous (iv) and intracerebroventricular (icv) infusion of HNG acutely increase TG secretion from the liver. Vagotomy blocks the effect on both iv and icv HNG on TG secretion, suggesting that the effects of HNG on hepatic TG flux are centrally mediated. Our data suggest that HN is a new player in central regulation of peripheral lipid metabolism.
Collapse
Affiliation(s)
- Zhenwei Gong
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Kai Su
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Lingguang Cui
- Department of Pediatrics, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and
| | - Emir Tas
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Ting Zhang
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - H Henry Dong
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Shoshana Yakar
- David B. Kriser Dental Center, Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, New York
| | - Radhika H Muzumdar
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
| |
Collapse
|
17
|
Fang H, Chen QP. Leptin and maintenance of gastrointestinal function. Shijie Huaren Xiaohua Zazhi 2015; 23:2920-2927. [DOI: 10.11569/wcjd.v23.i18.2920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Leptin is a protein hormone encoded by the obese (Ob) gene, exerting an important biological role in the life. Initially, leptin is believed to play a major role in regulating appetite control and energy metabolism, including adjusting the energy metabolism. However, recent data suggest that leptin also plays an important part in regulating the function of the gastrointestinal tract, immune and inflammation response, injury repair, and tumor angiogenesis. This article reviews the protective effects of leptin on the function of the gastrointestinal tract.
Collapse
|
18
|
Mountjoy KG. Pro-Opiomelanocortin (POMC) Neurones, POMC-Derived Peptides, Melanocortin Receptors and Obesity: How Understanding of this System has Changed Over the Last Decade. J Neuroendocrinol 2015; 27:406-18. [PMID: 25872650 DOI: 10.1111/jne.12285] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/04/2015] [Accepted: 04/07/2015] [Indexed: 12/19/2022]
Abstract
Following the cloning of the melanocortin receptor and agouti protein genes, a model was developed for the central melanocortin system with respect to the regulation of energy and glucose homeostasis. This model comprised leptin regulation of melanocortin peptides and agouti-related peptide (AgRP) produced from central pro-opiomelanocortin (POMC) and AgRP neurones, respectively, as well as AgRP competitive antagonism of melanocortin peptides activating melanocortin 4 receptor (MC4R) to Gαs and the cAMP signalling pathway. In the last decade, there have been paradigm shifts in our understanding of the central melanocortin system as a result of the application of advanced new technologies, including Cre-LoxP transgenic mouse technology, pharmacogenetics and optogenetics. During this period, our understanding of G protein coupled receptor signal transduction has also dramatically changed, such that these receptors are now known to exist in the plasma membrane oscillating between various inactive and active conformational states, and the active states signal through G protein-dependent and G protein-independent pathways. The present review focuses on evidence obtained over the past decade that has changed our understanding of POMC gene expression and regulation in the central nervous system, POMC and AgRP neuronal circuitry, neuroanatomical functions of melanocortin receptors, melanocortin 3 receptor (MC3R) and MC4R, and signal transduction through MC3R and MC4R.
Collapse
Affiliation(s)
- K G Mountjoy
- Departments of Physiology and Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| |
Collapse
|
19
|
Jackson VM, Breen DM, Fortin JP, Liou A, Kuzmiski JB, Loomis AK, Rives ML, Shah B, Carpino PA. Latest approaches for the treatment of obesity. Expert Opin Drug Discov 2015; 10:825-39. [DOI: 10.1517/17460441.2015.1044966] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- V Margaret Jackson
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Danna M Breen
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Jean-Philippe Fortin
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Alice Liou
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - J Brent Kuzmiski
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - A Katrina Loomis
- 2Clinical Research, Pfizer PharmaTherapeutics, Eastern Point Road, Groton, CT 06340, USA
| | - Marie-Laure Rives
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Bhavik Shah
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Philip A Carpino
- 3Cardiovascular and Metabolic Diseases Medicinal Chemistry, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| |
Collapse
|
20
|
Abstract
Plasma levels of triacylglycerols and diacylglycerols, the lipoproteins that transport them, and proteins involved in their absorption from the intestinal lumen fluctuate in a circadian manner. These changes are likely controlled by clock genes expressed in the intestine that are probably synchronized by neuronal and humoral signals from the suprachiasmatic nuclei, which constitute a master clock entrained by light signals from the eyes and from the environment, e.g., food availability. Acute changes in circadian rhythms--e.g., due to nonsynchronous work schedules or a transcontinental flight--may trigger intestinal discomfort. Chronic disruptions in circadian control mechanisms may predispose the individual to irritable bowel syndrome, gastroesophageal reflux disease, and peptic ulcer disease. A more detailed understanding of the molecular mechanisms underlying temporal changes in intestinal activity might allow us to identify novel targets for developing therapeutic approaches to these disorders.
Collapse
Affiliation(s)
- M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York 11203, and Virginia New York Harbor Healthcare System, Brooklyn, New York 11209;
| |
Collapse
|
21
|
Hooper AJ, Burnett JR, Watts GF. Contemporary Aspects of the Biology and Therapeutic Regulation of the Microsomal Triglyceride Transfer Protein. Circ Res 2015; 116:193-205. [DOI: 10.1161/circresaha.116.304637] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Amanda J. Hooper
- Department of Clinical Biochemistry, PathWest Laboratory Medicine WA (A.J.H., J.R.B.), School of Medicine and Pharmacology (A.J.H., J.R.B., G.F.W.), School of Pathology and Laboratory Medicine (A.J.H), and Lipid Disorders Clinic, Cardiovascular Medicine (J.R.B., G.F.W), Royal Perth Hospital, University of Western Australia, Perth, Western Australia, Australia
| | - John R. Burnett
- Department of Clinical Biochemistry, PathWest Laboratory Medicine WA (A.J.H., J.R.B.), School of Medicine and Pharmacology (A.J.H., J.R.B., G.F.W.), School of Pathology and Laboratory Medicine (A.J.H), and Lipid Disorders Clinic, Cardiovascular Medicine (J.R.B., G.F.W), Royal Perth Hospital, University of Western Australia, Perth, Western Australia, Australia
| | - Gerald F. Watts
- Department of Clinical Biochemistry, PathWest Laboratory Medicine WA (A.J.H., J.R.B.), School of Medicine and Pharmacology (A.J.H., J.R.B., G.F.W.), School of Pathology and Laboratory Medicine (A.J.H), and Lipid Disorders Clinic, Cardiovascular Medicine (J.R.B., G.F.W), Royal Perth Hospital, University of Western Australia, Perth, Western Australia, Australia
| |
Collapse
|
22
|
Panaro BL, Tough IR, Engelstoft MS, Matthews RT, Digby GJ, Møller CL, Svendsen B, Gribble F, Reimann F, Holst JJ, Holst B, Schwartz TW, Cox HM, Cone RD. The melanocortin-4 receptor is expressed in enteroendocrine L cells and regulates the release of peptide YY and glucagon-like peptide 1 in vivo. Cell Metab 2014; 20:1018-29. [PMID: 25453189 PMCID: PMC4255280 DOI: 10.1016/j.cmet.2014.10.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 08/15/2014] [Accepted: 10/10/2014] [Indexed: 02/07/2023]
Abstract
The melanocortin-4 receptor (MC4R) is expressed in the brainstem and vagal afferent nerves and regulates a number of aspects of gastrointestinal function. Here we show that the receptor is also diffusely expressed in cells of the gastrointestinal system, from stomach to descending colon. Furthermore, MC4R is the second most highly enriched GPCR in peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) expressing enteroendocrine L cells. When vectorial ion transport is measured across mouse or human intestinal mucosa, administration of α-MSH induces a MC4R-specific PYY-dependent antisecretory response consistent with a role for the MC4R in paracrine inhibition of electrolyte secretion. Finally, MC4R-dependent acute PYY and GLP-1 release from L cells can be stimulated in vivo by intraperitoneal (i.p.) administration of melanocortin peptides to mice. This suggests physiological significance for MC4R in L cells and indicates a previously unrecognized peripheral role for the MC4R, complementing vagal and central receptor functions.
Collapse
Affiliation(s)
- Brandon L Panaro
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Iain R Tough
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus, London SE1 1UL, UK
| | - Maja S Engelstoft
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Danish Diabetes Academy, 5000 Odense, Denmark
| | - Robert T Matthews
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Gregory J Digby
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Cathrine L Møller
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Diabetes and Obesity Biology, Novo Nordisk A/S, 2760 Maaloev, Denmark
| | - Berit Svendsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Denmark
| | - Fiona Gribble
- University of Cambridge, Cambridge Institute for Medical Research (CIMR) & MRC Metabolic Diseases Unit (MDU), Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Frank Reimann
- University of Cambridge, Cambridge Institute for Medical Research (CIMR) & MRC Metabolic Diseases Unit (MDU), Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Danish Diabetes Academy, 5000 Odense, Denmark
| | - Birgitte Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark
| | - Thue W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark; Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Medical and Health Sciences, University of Copenhagen, 2200 Denmark
| | - Helen M Cox
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus, London SE1 1UL, UK
| | - Roger D Cone
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| |
Collapse
|
23
|
Arya N, Kharjul MD, Shishoo CJ, Thakare VN, Jain KS. Some molecular targets for antihyperlipidemic drug research. Eur J Med Chem 2014; 85:535-68. [DOI: 10.1016/j.ejmech.2014.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 12/17/2022]
|
24
|
Mazzoccoli G, Vinciguerra M, Oben J, Tarquini R, De Cosmo S. Non-alcoholic fatty liver disease: the role of nuclear receptors and circadian rhythmicity. Liver Int 2014; 34:1133-52. [PMID: 24649929 DOI: 10.1111/liv.12534] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 03/16/2014] [Indexed: 12/22/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the accumulation of triglycerides in the hepatocytes in the absence of excess alcohol intake, and is caused by an imbalance between hepatic synthesis and breakdown of fats, as well as fatty acid storage and disposal. Liver metabolic pathways are driven by circadian biological clocks, and hepatic health is maintained by proper timing of circadian patterns of metabolic gene expression with the alternation of anabolic processes corresponding to feeding/activity during wake times, and catabolic processes characterizing fasting/resting during sleep. A number of nuclear receptors in the liver are expressed rhythmically, bind hormones and metabolites, sense energy flux and expenditure, and connect the metabolic pathways to the molecular clockwork throughout the 24-h day. In this review, we describe the role played by the nuclear receptors in the genesis of NAFLD in relationship with the circadian clock circuitry.
Collapse
Affiliation(s)
- Gianluigi Mazzoccoli
- Division of Internal Medicine and Chronobiology Unit, Department of Medical Sciences, IRCCS Scientific Institute and Regional General Hospital "Casa Sollievo della Sofferenza", San Giovanni Rotondo (FG), Italy
| | | | | | | | | |
Collapse
|
25
|
Kooijman S, Boon MR, Parlevliet ET, Geerling JJ, van de Pol V, Romijn JA, Havekes LM, Meurs I, Rensen PCN. Inhibition of the central melanocortin system decreases brown adipose tissue activity. J Lipid Res 2014; 55:2022-32. [PMID: 25016380 DOI: 10.1194/jlr.m045989] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The melanocortin system is an important regulator of energy balance, and melanocortin 4 receptor (MC4R) deficiency is the most common monogenic cause of obesity. We investigated whether the relationship between melanocortin system activity and energy expenditure (EE) is mediated by brown adipose tissue (BAT) activity. Therefore, female APOE*3-Leiden.CETP transgenic mice were fed a Western-type diet for 4 weeks and infused intracerebroventricularly with the melanocortin 3/4 receptor (MC3/4R) antagonist SHU9119 or vehicle for 2 weeks. SHU9119 increased food intake (+30%) and body fat (+50%) and decreased EE by reduction in fat oxidation (-42%). In addition, SHU9119 impaired the uptake of VLDL-TG by BAT. In line with this, SHU9119 decreased uncoupling protein-1 levels in BAT (-60%) and induced large intracellular lipid droplets, indicative of severely disturbed BAT activity. Finally, SHU9119-treated mice pair-fed to the vehicle-treated group still exhibited these effects, indicating that MC4R inhibition impairs BAT activity independent of food intake. These effects were not specific to the APOE*3-Leiden.CETP background as SHU9119 also inhibited BAT activity in wild-type mice. We conclude that inhibition of central MC3/4R signaling impairs BAT function, which is accompanied by reduced EE, thereby promoting adiposity. We anticipate that activation of MC4R is a promising strategy to combat obesity by increasing BAT activity.
Collapse
Affiliation(s)
- Sander Kooijman
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mariëtte R Boon
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Edwin T Parlevliet
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands Department of Internal Medicine, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Janine J Geerling
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Vera van de Pol
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Johannes A Romijn
- Department of Internal Medicine, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Louis M Havekes
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands Netherlands Organization for Applied Scientific Research, Gaubius Laboratory, Leiden, The Netherlands
| | - Illiana Meurs
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Patrick C N Rensen
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
26
|
Tavernier A, Cavin JB, Le Gall M, Ducroc R, Denis RGP, Cluzeaud F, Guilmeau S, Sakar Y, Barbot L, Kapel N, Le Beyec J, Joly F, Chua S, Luquet S, Bado A. Intestinal deletion of leptin signaling alters activity of nutrient transporters and delayed the onset of obesity in mice. FASEB J 2014; 28:4100-10. [PMID: 24928195 DOI: 10.1096/fj.14-255158] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/27/2014] [Indexed: 11/11/2022]
Abstract
The importance of B-isoform of leptin receptor (LEPR-B) signaling in the hypothalamus, pancreas, or liver has been well characterized, but in the intestine, a unique site of entry for dietary nutrition into the body, it has been relatively ignored. To address this question, we characterized a mouse model deficient for LEPR-B specifically in intestinal epithelial cells (IECs). (IEC)LEPR-B-knockout (KO) and wild-type (WT) mice were generated by Cre-Lox strategy and fed a normal or high-fat diet (HFD). The analyses of the animals involved histology and immunohistochemistry of intestinal mucosa, indirect calorimetric measurements, whole-body composition, and expression and activities of nutrient transporters. (IEC)LEPR-B-KO mice exhibited a 2-fold increase in length of jejunal villi and have normal growth on a normal diet but were less susceptible (P<0.01) to HFD-induced obesity. No differences occurred in energy intake and expenditure between (IEC)LEPR-B-WT and -KO mice, but (IEC)LEPR-B-KO mice fed an HFD showed increased excreted fats (P<0.05). Activities of the Na(+)/glucose cotransporter SGLT-1 and GLUT2 were unaffected in LEPR-B-KO jejunum, while GLUT5-mediated fructose transport and PepT1-mediated peptide transport were substantially reduced (P<0.01). These data demonstrate that intestinal LEPR-B signaling is important for the onset of diet-induced obesity. They suggest that intestinal LEPR-B could be a potential per os target for prevention against obesity.
Collapse
Affiliation(s)
- Annabelle Tavernier
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Jean-Baptiste Cavin
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Maude Le Gall
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Robert Ducroc
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Raphaël G P Denis
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 8251, Paris, France
| | - Françoise Cluzeaud
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Sandra Guilmeau
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Yassine Sakar
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Laurence Barbot
- Service de Coprologie Fonctionnelle, Hopital La Pitié Salpêtrière, Paris, France
| | - Nathalie Kapel
- Service de Coprologie Fonctionnelle, Hopital La Pitié Salpêtrière, Paris, France
| | - Johanne Le Beyec
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France; Université Pierre et Marie Curie, Paris, France
| | - Francisca Joly
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France; Service de Gastroenterologie et d'Assistance Nutritive, Hopital Beaujon, Clichy, France; and
| | - Streamson Chua
- Department of Medicine and Neuroscience, Albert Einstein College of Medicine, New York, New York, USA
| | - Serge Luquet
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 8251, Paris, France
| | - Andre Bado
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche en Santé (UMRS) 1149, Unité de Formation et de Recherche (UFR) de Médecine Paris Diderot, Sorbonne Paris Cite, Paris, France;
| |
Collapse
|
27
|
Côté CD, Zadeh-Tahmasebi M, Rasmussen BA, Duca FA, Lam TKT. Hormonal signaling in the gut. J Biol Chem 2014; 289:11642-11649. [PMID: 24577102 DOI: 10.1074/jbc.o114.556068] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The gut is anatomically positioned to play a critical role in the regulation of metabolic homeostasis, providing negative feedback via nutrient sensing and local hormonal signaling. Gut hormones, such as cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1), are released following a meal and act on local receptors to regulate glycemia via a neuronal gut-brain axis. Additionally, jejunal nutrient sensing and leptin action are demonstrated to suppress glucose production, and both are required for the rapid antidiabetic effect of duodenal jejunal bypass surgery. Strategies aimed at targeting local gut hormonal signaling pathways may prove to be efficacious therapeutic options to improve glucose control in diabetes.
Collapse
Affiliation(s)
- Clémence D Côté
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7; Departments of Physiology, University of Toronto, Toronto, Ontario M5S 1A8
| | - Melika Zadeh-Tahmasebi
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7; Departments of Physiology, University of Toronto, Toronto, Ontario M5S 1A8
| | - Brittany A Rasmussen
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7; Departments of Physiology, University of Toronto, Toronto, Ontario M5S 1A8
| | - Frank A Duca
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7; Departments of Medicine, University of Toronto, Toronto, Ontario M5S 1A8
| | - Tony K T Lam
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7; Departments of Physiology, University of Toronto, Toronto, Ontario M5S 1A8; Departments of Medicine, University of Toronto, Toronto, Ontario M5S 1A8; Departments of Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario M5G 2C4, Canada.
| |
Collapse
|
28
|
Dikkers A, Annema W, de Boer JF, Iqbal J, Hussain MM, Tietge UJF. Differential impact of hepatic deficiency and total body inhibition of MTP on cholesterol metabolism and RCT in mice. J Lipid Res 2014; 55:816-25. [PMID: 24511105 DOI: 10.1194/jlr.m042986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Because apoB-containing lipoproteins are pro-atherogenic and their secretion by liver and intestine largely depends on microsomal triglyceride transfer protein (MTP) activity, MTP inhibition strategies are actively pursued. How decreasing the secretion of apoB-containing lipoproteins affects intracellular rerouting of cholesterol is unclear. Therefore, the aim of the present study was to determine the effects of reducing either systemic or liver-specific MTP activity on cholesterol metabolism and reverse cholesterol transport (RCT) using a pharmacological MTP inhibitor or a genetic model, respectively. Plasma total cholesterol and triglyceride levels were decreased in both MTP inhibitor-treated and liver-specific MTP knockout (L-Mttp(-/-)) mice (each P < 0.001). With both inhibition approaches, hepatic cholesterol as well as triglyceride content was consistently increased (each P < 0.001), while biliary cholesterol and bile acid secretion remained unchanged. A small but significant decrease in fecal bile acid excretion was observed in inhibitor-treated mice (P < 0.05), whereas fecal neutral sterol excretion was substantially increased by 75% (P < 0.001), conceivably due to decreased intestinal absorption. In contrast, in L-Mttp(-/-) mice both fecal neutral sterol and bile acid excretion remained unchanged. However, while total RCT increased in inhibitor-treated mice (P < 0.01), it surprisingly decreased in L-Mttp(-/-) mice (P < 0.05). These data demonstrate that: i) pharmacological MTP inhibition increases RCT, an effect that might provide additional clinical benefit of MTP inhibitors; and ii) decreasing hepatic MTP decreases RCT, pointing toward a potential contribution of hepatocyte-derived VLDLs to RCT.
Collapse
Affiliation(s)
- Arne Dikkers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | | | | | | | | | | |
Collapse
|
29
|
Rasmussen BA, Breen DM, Duca FA, Côté CD, Zadeh-Tahmasebi M, Filippi BM, Lam TKT. Jejunal leptin-PI3K signaling lowers glucose production. Cell Metab 2014; 19:155-61. [PMID: 24361011 DOI: 10.1016/j.cmet.2013.11.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/08/2013] [Accepted: 11/11/2013] [Indexed: 10/25/2022]
Abstract
The fat-derived hormone leptin binds to its hypothalamic receptors to regulate glucose homeostasis. Leptin is also synthesized in the stomach and subsequently binds to its receptors expressed in the intestine, although the functional relevance of such activation remains largely unknown. We report here that intrajejunal leptin administration activates jejunal leptin receptors and signals through a phosphatidylinositol 3-kinase (PI3K)-dependent and signal transducer and activator of transcription 3 (STAT3)-independent signaling pathway to lower glucose production in healthy rodents. Jejunal leptin action is sufficient to lower glucose production in uncontrolled diabetic and high-fat-fed rodents and contributes to the early antidiabetic effect of duodenal-jejunal bypass surgery. These data unveil a glucoregulatory site of leptin action and suggest that enhancing leptin-PI3K signaling in the jejunum lowers plasma glucose concentrations in diabetes.
Collapse
Affiliation(s)
- Brittany A Rasmussen
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Danna M Breen
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Frank A Duca
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Clémence D Côté
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Melika Zadeh-Tahmasebi
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Beatrice M Filippi
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tony K T Lam
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Banting and Best Diabetes Centre, University of Toronto, Toronto, ON M5G 2C4, Canada.
| |
Collapse
|
30
|
Iqbal J, Parks JS, Hussain MM. Lipid absorption defects in intestine-specific microsomal triglyceride transfer protein and ATP-binding cassette transporter A1-deficient mice. J Biol Chem 2013; 288:30432-30444. [PMID: 24019513 DOI: 10.1074/jbc.m113.501247] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We have previously described apolipoprotein B (apoB)-dependent and -independent cholesterol absorption pathways and the role of microsomal triglyceride transfer protein (MTP) and ATP-binding cassette transporter A1 (ABCA1) in these pathways. To assess the contribution of these pathways to cholesterol absorption and to determine whether there are other pathways, we generated mice that lack MTP and ABCA1, individually and in combination, in the intestine. Intestinal deletions of Mttp and Abca1 decreased plasma cholesterol concentrations by 45 and 24%, respectively, whereas their combined deletion reduced it by 59%. Acute cholesterol absorption was reduced by 28% in the absence of ABCA1, and it was reduced by 92-95% when MTP was deleted in the intestine alone or together with ABCA1. MTP deficiency significantly reduced triglyceride absorption, although ABCA1 deficiency had no effect. ABCA1 deficiency did not affect cellular lipids, but Mttp deficiency significantly increased intestinal levels of triglycerides and free fatty acids. Accumulation of intestinal free fatty acids, but not triglycerides, in Mttp-deficient intestines was prevented when mice were also deficient in intestinal ABCA1. Combined deficiency of these genes increased intestinal fatty acid oxidation as a consequence of increased expression of peroxisome proliferator-activated receptor-γ (PPARγ) and carnitine palmitoyltransferase 1α (CPT1α). These studies show that intestinal MTP and ABCA1 are critical for lipid absorption and are the main determinants of plasma and intestinal lipid levels. Reducing their activities might lower plasma lipid concentrations.
Collapse
Affiliation(s)
- Jahangir Iqbal
- From the Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, New York 11203 and
| | - John S Parks
- the Department of Pathology, Section on Lipid Sciences and Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 25157
| | - M Mahmood Hussain
- From the Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, New York 11203 and.
| |
Collapse
|
31
|
Do DN, Strathe AB, Ostersen T, Jensen J, Mark T, Kadarmideen HN. Genome-wide association study reveals genetic architecture of eating behavior in pigs and its implications for humans obesity by comparative mapping. PLoS One 2013; 8:e71509. [PMID: 23977060 PMCID: PMC3747221 DOI: 10.1371/journal.pone.0071509] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/01/2013] [Indexed: 01/07/2023] Open
Abstract
This study was aimed at identifying genomic regions controlling feeding behavior in Danish Duroc boars and its potential implications for eating behavior in humans. Data regarding individual daily feed intake (DFI), total daily time spent in feeder (TPD), number of daily visits to feeder (NVD), average duration of each visit (TPV), mean feed intake per visit (FPV) and mean feed intake rate (FR) were available for 1130 boars. All boars were genotyped using the Illumina Porcine SNP60 BeadChip. The association analyses were performed using the GenABEL package in the R program. Sixteen SNPs were found to have moderate genome-wide significance (p<5E-05) and 76 SNPs had suggestive (p<5E-04) association with feeding behavior traits. MSI2 gene on chromosome (SSC) 14 was very strongly associated with NVD. Thirty-six SNPs were located in genome regions where QTLs have previously been reported for behavior and/or feed intake traits in pigs. The regions: 64–65 Mb on SSC 1, 124–130 Mb on SSC 8, 63–68 Mb on SSC 11, 32–39 Mb and 59–60 Mb on SSC 12 harbored several signifcant SNPs. Synapse genes (GABRR2, PPP1R9B, SYT1, GABRR1, CADPS2, DLGAP2 and GOPC), dephosphorylation genes (PPM1E, DAPP1, PTPN18, PTPRZ1, PTPN4, MTMR4 and RNGTT) and positive regulation of peptide secretion genes (GHRH, NNAT and TCF7L2) were highly significantly associated with feeding behavior traits. This is the first GWAS to identify genetic variants and biological mechanisms for eating behavior in pigs and these results are important for genetic improvement of pig feed efficiency. We have also conducted pig-human comparative gene mapping to reveal key genomic regions and/or genes on the human genome that may influence eating behavior in human beings and consequently affect the development of obesity and metabolic syndrome. This is the first translational genomics study of its kind to report potential candidate genes for eating behavior in humans.
Collapse
Affiliation(s)
- Duy Ngoc Do
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | | | | | | | | |
Collapse
|
32
|
Girardet C, Butler AA. Neural melanocortin receptors in obesity and related metabolic disorders. Biochim Biophys Acta Mol Basis Dis 2013; 1842:482-94. [PMID: 23680515 DOI: 10.1016/j.bbadis.2013.05.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/16/2013] [Accepted: 05/03/2013] [Indexed: 12/11/2022]
Abstract
Obesity is a global health issue, as it is associated with increased risk of developing chronic conditions associated with disorders of metabolism such as type 2 diabetes and cardiovascular disease. A better understanding of how excessive fat accumulation develops and causes diseases of the metabolic syndrome is urgently needed. The hypothalamic melanocortin system is an important point of convergence connecting signals of metabolic status with the neural circuitry that governs appetite and the autonomic and neuroendocrine system controling metabolism. This system has a critical role in the defense of body weight and maintenance of homeostasis. Two neural melanocortin receptors, melanocortin 3 and 4 receptors (MC3R and MC4R), play crucial roles in the regulation of energy balance. Mutations in the MC4R gene are the most common cause of monogenic obesity in humans, and a large literature indicates a role in regulating both energy intake through the control of satiety and energy expenditure. In contrast, MC3Rs have a more subtle role in energy homeostasis. Results from our lab indicate an important role for MC3Rs in synchronizing rhythms in foraging behavior with caloric cues and maintaining metabolic homeostasis during periods of nutrient scarcity. However, while deletion of the Mc3r gene in mice alters nutrient partitioning to favor accumulation of fat mass no obvious role for MC3R haploinsufficiency in human obesity has been reported. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.
Collapse
MESH Headings
- Animals
- Body Weight/genetics
- Cardiovascular Diseases/complications
- Cardiovascular Diseases/metabolism
- Cardiovascular Diseases/pathology
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Humans
- Metabolic Diseases/genetics
- Metabolic Diseases/metabolism
- Metabolic Diseases/pathology
- Mice
- Obesity/complications
- Obesity/genetics
- Obesity/metabolism
- Obesity/pathology
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
Collapse
Affiliation(s)
- Clemence Girardet
- Department of Metabolism and Aging, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Andrew A Butler
- Department of Metabolism and Aging, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
| |
Collapse
|
33
|
Suazo J, Hodgson MI, Obregón AM, Valladares M, Weisstaub G, Amador P, Santos JL. Prevalence of metabolic syndrome in obese Chilean children and association with gene variants of the leptin-melanocortin system. J Pediatr Endocrinol Metab 2013; 26:1131-9. [PMID: 23817596 DOI: 10.1515/jpem-2013-0084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 05/14/2013] [Indexed: 11/15/2022]
Abstract
Metabolic syndrome (MS) related to adult type 2 diabetes mellitus and cardiovascular disease is prevalent among obese children/adolescents. Genetic variants of the leptin-melanocortin system have been associated with components of MS. The aim of our study is to estimate the prevalence of MS (according to Cook's criteria) in a Chilean cross-sectional sample of 259 obese children (47.1% girls, aged 6-12 years), and to assess the association between common genetic variants of leptin-melanocortin pathway genes (LEP, LEPR, POMC, MC3R and MC4R) with components of the MS using logistic regression. We observed an overall MS prevalence of 26.3% (32.2% in girls and 21.1% in boys) in obese Chilean children. No associations were detected between genetic variants of leptin-melanocortin genes and MS components. MS prevalence among our obese children sample is similar to those previously described in Chile, demonstrating the increased risk of diseases in adulthood that obese children carry.
Collapse
|
34
|
Melanocortin-4 Receptor in Energy Homeostasis and Obesity Pathogenesis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:147-91. [DOI: 10.1016/b978-0-12-386933-3.00005-4] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
35
|
Cheung WW, Mak RH. Melanocortin antagonism ameliorates muscle wasting and inflammation in chronic kidney disease. Am J Physiol Renal Physiol 2012; 303:F1315-24. [PMID: 22914778 DOI: 10.1152/ajprenal.00341.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aberrant melanocortin signaling has been implicated in the pathogenesis of wasting in chronic kidney disease (CKD). Previously, we demonstrated that agouti-related peptide (AgRP), a melenocortin-4 receptor antagonist, reduced CKD-associated cachexia in CKD mice. Our previous studies with AgRP utilized dual energy X-ray (DXA) densitometry to assess the body composition in mice (Cheung W, Kuo HJ, Markison S, Chen C, Foster AC, Marks DL, Mak RH. J Am Soc Nephrol 18: 2517-2524, 2007; Cheung W, Yu PX, Little BM, Cone RD, Marks DL, Mak RH. J Clin Invest 115: 1659-1665, 2005). DXA is unable to differentiate water content in mice, and fluid retention in CKD may lead to an overestimate of lean mass. In this study, we employed quantitative magnetic resonance technique to evaluate body composition change following central administration of AgRP in a CKD mouse model. AgRP treatment improved energy expenditure, total body mass, fat mass, and lean body mass in CKD mouse. We also investigated the effect of CKD-associated cachexia on the signaling pathways leading to wasting in skeletal muscle, as well as whether these changes can be ameliorated by central administration of AgRP. AgRP treatment caused an overall decrease in proinflammatory cytokines, which may be one important mechanism of its effects. Muscle wasting in CKD may be due to the activation of proteolytic pathways as well as inhibition of myogenesis and muscle regeneration processes. Our results suggest that these aberrant pathological pathways leading to muscle wasting in CKD mice were ameliorated by central administration of AgRP.
Collapse
Affiliation(s)
- Wai W Cheung
- Pediatric Nephrology, University of California, San Diego, California, USA
| | | |
Collapse
|
36
|
Mazzoccoli G, Pazienza V, Vinciguerra M. Clock genes and clock-controlled genes in the regulation of metabolic rhythms. Chronobiol Int 2012; 29:227-51. [PMID: 22390237 DOI: 10.3109/07420528.2012.658127] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Daily rotation of the Earth on its axis and yearly revolution around the Sun impose to living organisms adaptation to nyctohemeral and seasonal periodicity. Terrestrial life forms have developed endogenous molecular circadian clocks to synchronize their behavioral, biological, and metabolic rhythms to environmental cues, with the aim to perform at their best over a 24-h span. The coordinated circadian regulation of sleep/wake, rest/activity, fasting/feeding, and catabolic/anabolic cycles is crucial for optimal health. Circadian rhythms in gene expression synchronize biochemical processes and metabolic fluxes with the external environment, allowing the organism to function effectively in response to predictable physiological challenges. In mammals, this daily timekeeping is driven by the biological clocks of the circadian timing system, composed of master molecular oscillators within the suprachiasmatic nuclei of the hypothalamus, pacing self-sustained and cell-autonomous molecular oscillators in peripheral tissues through neural and humoral signals. Nutritional status is sensed by nuclear receptors and coreceptors, transcriptional regulatory proteins, and protein kinases, which synchronize metabolic gene expression and epigenetic modification, as well as energy production and expenditure, with behavioral and light-dark alternance. Physiological rhythmicity characterizes these biological processes and body functions, and multiple rhythms coexist presenting different phases, which may determine different ways of coordination among the circadian patterns, at both the cellular and whole-body levels. A complete loss of rhythmicity or a change of phase may alter the physiological array of rhythms, with the onset of chronodisruption or internal desynchronization, leading to metabolic derangement and disease, i.e., chronopathology.
Collapse
Affiliation(s)
- Gianluigi Mazzoccoli
- Department of Medical Sciences, Division of Internal Medicine and Chronobiology Unit, IRCCS Scientific Institute and Regional General Hospital Casa Sollievo della Sofferenza, Opera di Padre Pio da Pietrelcina, San Giovanni Rotondo (FG), Italy.
| | | | | |
Collapse
|
37
|
Abstract
Intestinal lipid transport plays a central role in fat homeostasis. Here we review the pathways regulating intestinal absorption and delivery of dietary and biliary lipid substrates, principally long-chain fatty acid, cholesterol, and other sterols. We discuss the regulation and functions of CD36 in fatty acid absorption, NPC1L1 in cholesterol absorption, as well as other lipid transporters including FATP4 and SRB1. We discuss the pathways of intestinal sterol efflux via ABCG5/G8 and ABCA1 as well as the role of the small intestine in high-density lipoprotein (HDL) biogenesis and reverse cholesterol transport. We review the pathways and genetic regulation of chylomicron assembly, the role of dominant restriction points such as microsomal triglyceride transfer protein and apolipoprotein B, and the role of CD36, l-FABP, and other proteins in formation of the prechylomicron complex. We will summarize current concepts of regulated lipoprotein secretion (including HDL and chylomicron pathways) and include lessons learned from families with genetic mutations in dominant pathways (i.e., abetalipoproteinemia, chylomicron retention disease, and familial hypobetalipoproteinemia). Finally, we will provide an integrative view of intestinal lipid homeostasis through recent findings on the role of lipid flux and fatty acid signaling via diverse receptor pathways in regulating absorption and production of satiety factors.
Collapse
Affiliation(s)
- Nada A Abumrad
- Center for Human Nutrition and Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | | |
Collapse
|
38
|
Fox EA, Biddinger JE. Early postnatal overnutrition: potential roles of gastrointestinal vagal afferents and brain-derived neurotrophic factor. Physiol Behav 2012; 106:400-12. [PMID: 22712064 PMCID: PMC3517218 DOI: 10.1016/j.physbeh.2012.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abnormal perinatal nutrition (APN) results in a predisposition to develop obesity and the metabolic syndrome and thus may contribute to the prevalence of these disorders. Obesity, including that which develops in organisms exposed to APN, has been associated with increased meal size. Vagal afferents of the gastrointestinal (GI) tract contribute to regulation of meal size by transmitting satiation signals from gut-to-brain. Consequently, APN could increase meal size by altering this signaling, possibly through changes in expression of factors that control vagal afferent development or function. Here two studies that addressed these possibilities are reviewed. First, meal patterns, meal microstructure, and the structure and density of vagal afferents that innervate the intestine were examined in mice that experienced early postnatal overnutrition (EPO). These studies provided little evidence for EPO effects on vagal afferents as it did not alter meal size or vagal afferent density or structure. However, these mice exhibited modest hyperphagia due to a satiety deficit. In parallel, the possibility that brain-derived neurotrophic factor (BDNF) could mediate APN effects on vagal afferent development was investigated. Brain-derived neurotrophic factor was a strong candidate because APN alters BDNF levels in some tissues and BDNF knockout disrupts development of vagal sensory innervation of the GI tract. Surprisingly, smooth muscle-specific BDNF knockout resulted in early-onset obesity and hyperphagia due to increases in meal size and frequency. Microstructure analysis revealed decreased decay of intake rate during a meal in knockouts, suggesting that the loss of vagal negative feedback contributed to their increase in meal size. However, meal-induced c-Fos activation within the dorsal vagal complex suggested this effect could be due to augmentation of vago-vagal reflexes. A model is proposed to explain how high-fat diet consumption produces increased obesity in organisms exposed to APN, and may be required to reveal effects of EPO on vagal function.
Collapse
Affiliation(s)
- Edward A Fox
- Behavioral Neurogenetics Laboratory & Ingestive Behavior Research Center, Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
| | | |
Collapse
|
39
|
Douglass JD, Malik N, Chon SH, Wells K, Zhou YX, Choi AS, Joseph LB, Storch J. Intestinal mucosal triacylglycerol accumulation secondary to decreased lipid secretion in obese and high fat fed mice. Front Physiol 2012; 3:25. [PMID: 22375121 PMCID: PMC3285813 DOI: 10.3389/fphys.2012.00025] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 02/03/2012] [Indexed: 12/20/2022] Open
Abstract
The ectopic deposition of fat in liver and muscle during obesity is well established, however surprisingly little is known about the intestine. We used the ob/ob mouse and C57BL6/J mice fed a high fat (HF) diet to examine the effects of obesity and the effects of HF feeding, respectively, on intestinal mucosal triacylglycerol (TG) accumulation. Male C57BL6/J (wild-type, WT) mice were fed low fat (LF; 10% kcal as fat) or HF (45%) diets, and ob/ob mice were fed the LF diet, for 3 weeks. In this time frame, the WT–HF mice did not become obese, enabling independent examination of effects of the HF diet and effects of obesity. Analysis of intestinal lipid extracts from fed and fasted animals demonstrated that the mucosa, like other tissues, accumulates excess lipid. In the fed state, mucosal triacylglycerol (TG) levels were threefold and fivefold higher in the WT–HF and ob/ob mice, respectively, relative to the WT–LF mice. In the fasted state, mucosa from ob/ob mice had threefold higher TG levels relative to WT–LF mucosa. q-PCR analysis of mucosal mRNA from fed state mice showed alterations in the expression of several genes related to both anabolic and catabolic lipid metabolism pathways in WT–HF and ob/ob mice relative to WT–LF controls. Fewer changes were found in mucosal samples from the fasted state animals. Remarkably, oral fat tolerance tests showed a striking reduction in the plasma appearance of an oral fat load in the ob/ob and WT–HF mice compared to WT–LF. Overall, the results demonstrate that the intestinal mucosa accumulates excess TG during obesity. Changes in the expression of lipid metabolic and transport genes, as well as reduced secretion of dietary lipid from the mucosal cells into the circulation, may contribute to the TG accumulation in intestinal mucosa during obesity. Moreover, even in the absence of frank obesity, HF feeding leads to a large decrease in the rate of intestinal lipid secretion.
Collapse
Affiliation(s)
- John D Douglass
- Department of Nutritional Sciences, School of Environmental and Biological Sciences, Rutgers University New Brunswick, NJ, USA
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Hussain MM, Rava P, Walsh M, Rana M, Iqbal J. Multiple functions of microsomal triglyceride transfer protein. Nutr Metab (Lond) 2012; 9:14. [PMID: 22353470 PMCID: PMC3337244 DOI: 10.1186/1743-7075-9-14] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/21/2012] [Indexed: 02/08/2023] Open
Abstract
Microsomal triglyceride transfer protein (MTP) was first identified as a major cellular protein capable of transferring neutral lipids between membrane vesicles. Its role as an essential chaperone for the biosynthesis of apolipoprotein B (apoB)-containing triglyceride-rich lipoproteins was established after the realization that abetalipoproteinemia patients carry mutations in the MTTP gene resulting in the loss of its lipid transfer activity. Now it is known that it also plays a role in the biosynthesis of CD1, glycolipid presenting molecules, as well as in the regulation of cholesterol ester biosynthesis. In this review, we will provide a historical perspective about the identification, purification and characterization of MTP, describe methods used to measure its lipid transfer activity, and discuss tissue expression and function. Finally, we will review the role MTP plays in the assembly of apoB-lipoprotein, the regulation of cholesterol ester synthesis, biosynthesis of CD1 proteins and propagation of hepatitis C virus. We will also provide a brief overview about the clinical potentials of MTP inhibition.
Collapse
Affiliation(s)
- M Mahmood Hussain
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Paul Rava
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Meghan Walsh
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Muhammad Rana
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Jahangir Iqbal
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| |
Collapse
|
41
|
Alam T, Kenny DA, Sweeney T, Buckley F, Prendiville R, McGee M, Waters SM. Expression of genes involved in energy homeostasis in the duodenum and liver of Holstein-Friesian and Jersey cows and their F1 hybrid. Physiol Genomics 2012; 44:198-209. [DOI: 10.1152/physiolgenomics.00102.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Differences in feed intake and production efficiency in lactating Holstein-Friesian (HF), Jersey (JE), and JE × HF (F1) dairy cows have been reported. The liver-gut axis is important in the regulation of energy homeostasis, appetite behaviour, and production efficiency. The objectives of this study were to determine: 1) the effect of dairy cow genotype on the expression profiles of genes involved in energy homeostasis in duodenal and hepatic tissue, and 2) the association between the expression of these genes across both tissues and with economically important production efficiency traits. The expression of 27 candidate genes involved in energy homeostasis, feed intake, and energy storage was measured by qPCR. Duodenal expression of the pro-opiomelanocortin ( POMC), glucagon-like peptide 1 receptor ( GLP1R), and insulin-like growth factor 1 ( IGF1) genes was highest in HF. In contrast, hepatic expression of the leptin receptor ( LEPR), insulin-like growth factor 1 receptor ( IGF1R), protein kinase, AMP-activated, beta 1 ( AMPKB1), and POMC genes was highest in the F1 cross. In the duodenum, positive correlations were observed between mRNA expression of anorectic peptides ( POMC and GLP1R), whereas a negative correlation was detected between orexigenic (ghrelin) and anorectic (peptide YY) gene expression. A negative correlation was observed between duodenal POMC gene expression and both residual feed intake and milk production efficiency traits, while GLP1R gene expression was negatively correlated with milk production efficiency traits. A heterotic effect was observed in hepatic expression of AMKPB1, IGF1R, LEPR, POMC in the F1 genotype, possibly mediating improved feed efficiency in cross-bred cows. In conclusion, key genes involved in energy homeostasis and appetite behaviour are differentially expressed due to cow genotype in a tissue-dependent fashion. POMC and GLP1R are potential candidate genes for the identification of single nucleotide polymorphisms regulating energetic efficiency in the dairy cow, which may be incorporated into future breeding programmes.
Collapse
Affiliation(s)
- Tanweer Alam
- Cell and Molecular Biology Laboratory, Veterinary Science Centre, University College Dublin, Dublin
- Animal and Bioscience Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath
| | - David A. Kenny
- Animal and Bioscience Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath
| | - Torres Sweeney
- Cell and Molecular Biology Laboratory, Veterinary Science Centre, University College Dublin, Dublin
| | - Frank Buckley
- Teagasc, Moorepark Dairy Production Research Centre, Fermoy, Co. Cork; and
| | - Robert Prendiville
- Teagasc, Moorepark Dairy Production Research Centre, Fermoy, Co. Cork; and
| | - Mark McGee
- Livestock Systems Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - Sinead M. Waters
- Animal and Bioscience Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath
| |
Collapse
|
42
|
Pan X, Hussain MM. Gut triglyceride production. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:727-35. [PMID: 21989069 DOI: 10.1016/j.bbalip.2011.09.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 10/17/2022]
Abstract
Our knowledge of how the body absorbs triacylglycerols (TAG) from the diet and how this process is regulated has increased at a rapid rate in recent years. Dietary TAG are hydrolyzed in the intestinal lumen to free fatty acids (FFA) and monoacylglycerols (MAG), which are taken up by enterocytes from their apical side, transported to the endoplasmic reticulum (ER) and resynthesized into TAG. TAG are assembled into chylomicrons (CM) in the ER, transported to the Golgi via pre-chylomicron transport vesicles and secreted towards the basolateral side. In this review, we mainly focus on the roles of key proteins involved in uptake and intracellular transport of fatty acids, their conversion to TAG and packaging into CM. We will also discuss intracellular transport and secretion of CM. Moreover, we will bring to light few factors that regulate gut triglyceride production. Furthermore, we briefly summarize pathways involved in cholesterol absorption. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
Collapse
Affiliation(s)
- Xiaoyue Pan
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY 11203, USA.
| | | |
Collapse
|
43
|
Xiao C, Hsieh J, Adeli K, Lewis GF. Gut-liver interaction in triglyceride-rich lipoprotein metabolism. Am J Physiol Endocrinol Metab 2011; 301:E429-46. [PMID: 21693689 DOI: 10.1152/ajpendo.00178.2011] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The liver and intestine have complementary and coordinated roles in lipoprotein metabolism. Despite their highly specialized functions, assembly and secretion of triglyceride-rich lipoproteins (TRL; apoB-100-containing VLDL in the liver and apoB-48-containing chylomicrons in the intestine) are regulated by many of the same hormonal, inflammatory, nutritional, and metabolic factors. Furthermore, lipoprotein metabolism in these two organs may be affected in a similar fashion by certain disorders. In insulin resistance, for example, overproduction of TRL by both liver and intestine is a prominent component of and underlies other features of a complex dyslipidemia and increased risk of atherosclerosis. The intestine is gaining increasing recognition for its importance in affecting whole body lipid homeostasis, in part through its interaction with the liver. This review aims to integrate recent advances in our understanding of these processes and attempts to provide insight into the factors that coordinate lipid homeostasis in these two organs in health and disease.
Collapse
|
44
|
Mourad FH, Saadé NE. Neural regulation of intestinal nutrient absorption. Prog Neurobiol 2011; 95:149-62. [PMID: 21854830 DOI: 10.1016/j.pneurobio.2011.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 04/28/2011] [Accepted: 07/20/2011] [Indexed: 12/17/2022]
Abstract
The nervous system and the gastrointestinal (GI) tract share several common features including reciprocal interconnections and several neurotransmitters and peptides known as gut peptides, neuropeptides or hormones. The processes of digestion, secretion of digestive enzymes and then absorption are regulated by the neuro-endocrine system. Luminal glucose enhances its own absorption through a neuronal reflex that involves capsaicin sensitive primary afferent (CSPA) fibres. Absorbed glucose stimulates insulin release that activates hepatoenteric neural pathways leading to an increase in the expression of glucose transporters. Adrenergic innervation increases glucose absorption through α1 and β receptors and decreases absorption through activation of α2 receptors. The vagus nerve plays an important role in the regulation of diurnal variation in transporter expression and in anticipation to food intake. Vagal CSPAs exert tonic inhibitory effects on amino acid absorption. It also plays an important role in the mediation of the inhibitory effect of intestinal amino acids on their own absorption at the level of proximal or distal segment. However, chronic extrinsic denervation leads to a decrease in intestinal amino acid absorption. Conversely, adrenergic agonists as well as activation of CSPA fibres enhance peptides uptake through the peptide transporter PEPT1. Finally, intestinal innervation plays a minimal role in the absorption of fat digestion products. Intestinal absorption of nutrients is a basic vital mechanism that depends essentially on the function of intestinal mucosa. However, intrinsic and extrinsic neural mechanisms that rely on several redundant loops are involved in immediate and long-term control of the outcome of intestinal function.
Collapse
Affiliation(s)
- Fadi H Mourad
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
| | | |
Collapse
|
45
|
Warnakula S, Hsieh J, Adeli K, Hussain MM, Tso P, Proctor SD. New insights into how the intestine can regulate lipid homeostasis and impact vascular disease: frontiers for new pharmaceutical therapies to lower cardiovascular disease risk. Can J Cardiol 2011; 27:183-91. [PMID: 21459267 DOI: 10.1016/j.cjca.2010.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 06/07/2010] [Indexed: 01/27/2023] Open
Abstract
In recent years, evidence has emerged that the intestine is a significant regulator of systemic cholesterol homeostasis and can contribute to raised plasma cholesterol concentration. In this review we provide a context for the role the intestine may have in cardiovascular disease during conditions of chronic disease (insulin resistance, obesity). In particular, we highlight the physiological role of the intestine in lipid absorption, identify novel elements in enterocyte molecular biology, review the concept that chylomicrons and their remnants contribute to atherogenesis during chronic disease, and address new principles of chylomicron overproduction during conditions of insulin resistance including the associated hormonal control of the intestine during these conditions. Finally, we raise the issue of a growing need for novel lipid-lowering pharmaceutical therapies that target intestinal lipid metabolism.
Collapse
|
46
|
Hussain MM, Nijstad N, Franceschini L. Regulation of microsomal triglyceride transfer protein. ACTA ACUST UNITED AC 2011; 6:293-303. [PMID: 21808658 DOI: 10.2217/clp.11.21] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microsomal triglyceride transfer protein (MTP) facilitates the transport of dietary and endogenous fat by the intestine and liver by assisting in the assembly and secretion of triglyceride-rich apolipoprotein B-containing lipoproteins. Higher concentrations of apolipoprotein B lipoproteins predispose individuals to various cardiovascular and metabolic diseases such as atherosclerosis, diabetes, obesity and the metabolic syndrome. These can potentially be avoided by reducing MTP activity. In this article, we discuss regulation of MTP during development, cellular differentiation and diurnal variation. Furthermore, we focus on the regulation of MTP that occurs at transcriptional, post-transcriptional and post-translational levels. Transcriptional regulation of MTP depends on a few highly conserved cis-elements in the promoter. Several transcription factors that bind to these elements and either increase or decrease MTP expression have been identified. Additionally, MTP is regulated by macronutrients, hormones and other factors. This article will address the many ways in which MTP is regulated and advance the idea that reducing MTP levels, rather than its inhibition, might be an option to lower plasma lipids.
Collapse
Affiliation(s)
- M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, The State University of New York, Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA
| | | | | |
Collapse
|
47
|
Guo X, Roberts MR, Becker SM, Podd B, Zhang Y, Chua SC, Myers MG, Duggal P, Houpt ER, Petri WA. Leptin signaling in intestinal epithelium mediates resistance to enteric infection by Entamoeba histolytica. Mucosal Immunol 2011; 4:294-303. [PMID: 21124310 PMCID: PMC3079783 DOI: 10.1038/mi.2010.76] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Leptin is an adipocytokine that links nutrition to immunity. Previous observation that a genetic polymorphism in the leptin receptor affected susceptibility to Entamoeba histolytica infection led to the hypothesis that leptin signaling has a protective role during intestinal amebic infection. In this study we show that mice lacking the functional leptin receptor developed devastating mucosal destruction after E. histolytica infection. Bone marrow chimera experiments demonstrated that leptin receptor expressed on hematopoietic cells was not sufficient to confer resistance. Similarly, peripheral knockout of the leptin receptor rendered animals susceptible, indicating that central expression of the leptin receptor was not sufficient to confer protection. The site of leptin action was localized to the gut via an intestinal epithelium-specific deletion of the leptin receptor, which rendered mice susceptible to infection and mucosal destruction by the parasite. Mutation of tyrosine 985 or 1138 in the intracellular domain of the leptin receptor, which mediates signaling through the SH2-containing tyrosine phosphatase/extracellular signal-regulated kinase (SHP2/ERK) and signal transducer and activator of transcription 3 (STAT3) pathways, respectively, demonstrated that both were important for mucosal protection. We conclude that leptin-mediated resistance to amebiasis is via its actions on intestinal epithelium rather than hematopoietic cells or the brain, and requires leptin receptor signaling through both the STAT3 and SHP2/ERK pathways.
Collapse
Affiliation(s)
- Xiaoti Guo
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Margo R. Roberts
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Stephen M. Becker
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Bradley Podd
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Yiying Zhang
- Department of Pediatrics, Division of Molecular Genetics & Naomi Berrie Diabetes Center Columbia University Medical Center, New York, New York
| | - Streamson C. Chua
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Martin G. Myers
- Departments of Internal Medicine & Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Priya Duggal
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Eric R. Houpt
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia.,Corresponding Authors: William A. Petri, Jr., Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 434 924 5621 (direct), 434 924 0075 (fax) , *Eric R. Houpt, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 434 243 9326 (direct), 434 924 0075 (fax)
| | - William A. Petri
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| |
Collapse
|
48
|
Lyte M, Vulchanova L, Brown DR. Stress at the intestinal surface: catecholamines and mucosa-bacteria interactions. Cell Tissue Res 2010; 343:23-32. [PMID: 20941511 DOI: 10.1007/s00441-010-1050-0] [Citation(s) in RCA: 178] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 09/01/2010] [Indexed: 02/08/2023]
Abstract
Psychological stress has profound effects on gastrointestinal function, and investigations over the past few decades have examined the mechanisms by which neural and hormonal stress mediators act to modulate gut motility, epithelial barrier function and inflammatory states. With its cellular diversity and large commensal bacterial population, the intestinal mucosa and its overlying mucous environment constitute a highly interactive environment for eukaryotic host cells and prokaryotic bacteria. The elaboration of stress mediators, particularly norepinephrine, at this interface influences host cells engaged in mucosal protection and the bacteria which populate the mucosal surface and gut lumen. This review will address growing evidence that norepinephrine and, in some cases, other mediators of the adaptation to stress modulate mucosal interactions with enteric bacteria. Stress-mediated changes in this delicate interplay may shift the microbial colonization patterns on the mucosal surface and alter the susceptibility of the host to infection. Moreover, changes in host-microbe interactions in the digestive tract may also influence ongoing neural activity in stress-responsive brain areas.
Collapse
Affiliation(s)
- Mark Lyte
- Department of Pharmacy Practice, Texas Tech University Health Sciences Center, 3601 4th Street, MS 8162, Lubbock, TX 79430-8162, USA.
| | | | | |
Collapse
|
49
|
|