1
|
Modvig IM, Smits MM, Galsgaard KD, Hjørne AP, Drzazga AK, Rosenkilde MM, Holst JJ. L-valine is a powerful stimulator of GLP-1 secretion in rodents and stimulates secretion through ATP-sensitive potassium channels and voltage-gated calcium channels. Nutr Diabetes 2024; 14:43. [PMID: 38862477 PMCID: PMC11166632 DOI: 10.1038/s41387-024-00303-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/13/2024] Open
Abstract
BACKGROUND We previously reported that, among all the naturally occurring amino acids, L-valine is the most powerful luminal stimulator of glucagon-like peptide 1 (GLP-1) release from the upper part of the rat small intestine. This makes L-valine an interesting target for nutritional-based modulation of GLP-1 secretion. However, the molecular mechanism of L-valine-induced secretion remains unknown. METHODS We aimed to investigate the effect of orally given L-valine in mice and to identify the molecular details of L-valine stimulated GLP-1 release using the isolated perfused rat small intestine and GLUTag cells. In addition, the effect of L-valine on hormone secretion from the distal intestine was investigated using a perfused rat colon. RESULTS Orally given L-valine (1 g/kg) increased plasma levels of active GLP-1 comparably to orally given glucose (2 g/kg) in male mice, supporting that L-valine is a powerful stimulator of GLP-1 release in vivo (P > 0.05). Luminal L-valine (50 mM) strongly stimulated GLP-1 release from the perfused rat small intestine (P < 0.0001), and inhibition of voltage-gated Ca2+-channels with nifedipine (10 μM) inhibited the GLP-1 response (P < 0.01). Depletion of luminal Na+ did not affect L-valine-induced GLP-1 secretion (P > 0.05), suggesting that co-transport of L-valine and Na+ is not important for the depolarization necessary to activate the voltage-gated Ca2+-channels. Administration of the KATP-channel opener diazoxide (250 μM) completely blocked the L-valine induced GLP-1 response (P < 0.05), suggesting that L-valine induced depolarization arises from metabolism and opening of KATP-channels. Similar to the perfused rat small intestine, L-valine tended to stimulate peptide tyrosine-tyrosine (PYY) and GLP-1 release from the perfused rat colon. CONCLUSIONS L-valine is a powerful stimulator of GLP-1 release in rodents. We propose that intracellular metabolism of L-valine leading to closure of KATP-channels and opening of voltage-gated Ca2+-channels are involved in L-valine induced GLP-1 secretion.
Collapse
Affiliation(s)
- Ida Marie Modvig
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mark M Smits
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Douglas Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna Pii Hjørne
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna Katarzyna Drzazga
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Łódź, Poland
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
2
|
Ramasamy I. Physiological Appetite Regulation and Bariatric Surgery. J Clin Med 2024; 13:1347. [PMID: 38546831 PMCID: PMC10932430 DOI: 10.3390/jcm13051347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/22/2024] [Accepted: 02/24/2024] [Indexed: 04/10/2024] Open
Abstract
Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.
Collapse
Affiliation(s)
- Indra Ramasamy
- Department of Blood Sciences, Conquest Hospital, Hastings TN37 7RD, UK
| |
Collapse
|
3
|
Zhang M, Zhu L, Wu G, Zhang H, Wang X, Qi X. The impacts and mechanisms of dietary proteins on glucose homeostasis and food intake: a pivotal role of gut hormones. Crit Rev Food Sci Nutr 2023:1-15. [PMID: 37800337 DOI: 10.1080/10408398.2023.2256400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Glucose and energy metabolism disorders are the main reasons induced type 2 diabetes (T2D) and obesity. Besides providing energy, dietary nutrients could regulate glucose homeostasis and food intake via intestinal nutrient sensing induced gut hormone secretion. However, reviews regarding intestinal protein sensing are very limited, and no accurate information is available on their underlying mechanisms. Through intestinal protein sensing, dietary proteins regulate glucose homeostasis and food intake by secreting gut hormones, such as glucagon-like peptide 1 (GLP-1), cholecystokinin (CCK), peptide YY (PYY) and glucose-dependent insulinotropic polypeptide (GIP). After activating the sensory receptors, such as calcium-sensing receptor (CaSR), peptide transporter-1 (PepT1), and taste 1 receptors (T1Rs), protein digests induced Ca2+ influx and thus triggered gut hormone release. Additionally, research models used to study intestinal protein sensing have been emphasized, especially several innovative models with excellent physiological relevance, such as co-culture cell models, intestinal organoids, and gut-on-a-chips. Lastly, protein-based dietary strategies that stimulate gut hormone secretion and inhibit gut hormone degradation are proposed for regulating glucose homeostasis and food intake.
Collapse
Affiliation(s)
- Mingkai Zhang
- National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Ling Zhu
- National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Gangcheng Wu
- National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Hui Zhang
- National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Xingguo Wang
- National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Xiguang Qi
- National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi, China
| |
Collapse
|
4
|
Masse KE, Lu VB. Short-chain fatty acids, secondary bile acids and indoles: gut microbial metabolites with effects on enteroendocrine cell function and their potential as therapies for metabolic disease. Front Endocrinol (Lausanne) 2023; 14:1169624. [PMID: 37560311 PMCID: PMC10407565 DOI: 10.3389/fendo.2023.1169624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 07/05/2023] [Indexed: 08/11/2023] Open
Abstract
The gastrointestinal tract hosts the largest ecosystem of microorganisms in the body. The metabolism of ingested nutrients by gut bacteria produces novel chemical mediators that can influence chemosensory cells lining the gastrointestinal tract. Specifically, hormone-releasing enteroendocrine cells which express a host of receptors activated by these bacterial metabolites. This review will focus on the activation mechanisms of glucagon-like peptide-1 releasing enteroendocrine cells by the three main bacterial metabolites produced in the gut: short-chain fatty acids, secondary bile acids and indoles. Given the importance of enteroendocrine cells in regulating glucose homeostasis and food intake, we will also discuss therapies based on these bacterial metabolites used in the treatment of metabolic diseases such as diabetes and obesity. Elucidating the mechanisms gut bacteria can influence cellular function in the host will advance our understanding of this fundamental symbiotic relationship and unlock the potential of harnessing these pathways to improve human health.
Collapse
Affiliation(s)
| | - Van B. Lu
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| |
Collapse
|
5
|
Taguchi H, Murai K, Hira T. Trp-Tyr is a dipeptide structure that potently stimulates GLP-1 secretion in a murine enteroendocrine cell model, identified by comprehensive analysis. Biochem Biophys Res Commun 2023; 661:28-33. [PMID: 37086571 DOI: 10.1016/j.bbrc.2023.04.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 04/15/2023] [Indexed: 04/24/2023]
Abstract
Dietary peptides potently stimulate glucagon-like peptide-1 (GLP-1) secretion, however, the underlying molecular mechanisms, such as structure-activity relationships and sensing mechanisms are only partly elucidated. In this study, we used a dipeptide library to identify dipeptides that potently stimulate GLP-1 release and to clarify the underlying structure-activity relationship. Murine enteroendocrine GLUTag cells were exposed to 339 dipeptides for 60 min, and the concentration of GLP-1 released into the supernatant was measured. Subsequently, selected dipeptides were examined for their reproducibility and dose responsiveness. In addition, we investigated the role of constituent amino acids in the secretion of GLP-1, and whether tripeptides containing the active dipeptide structures maintained their activity. In a concentration range of 1-5 mg/mL, twelve dipeptides had reproducible and concentration-dependent GLP-1-releasing activity. Among them, nine dipeptides (FY, KF, NI, PM, QL, QY, WF, WN, WY) were novel, with WY exhibiting the most potent activity. The reverse sequences and most free amino acids did not induce GLP-1 secretion, indicating that GLP-1-producing cells recognize the structure of each peptide to induce GLP-1 secretion. However, no apparent similarities were found between the active peptides. A comparison between the six tripeptides composed of F, W, and Y revealed the further potent tripeptides FWY and WYF, than WY. In the present study, a comprehensive analysis revealed nine novel dipeptides with high potential to stimulate GLP-1 secretion. Furthermore, the results indicate that 'WY' is a specific dipeptide sequence that potently stimulates GLP-1 secretion.
Collapse
Affiliation(s)
- Hayate Taguchi
- Graduate School of Agriculture, Hokkaido University, Japan
| | - Kana Murai
- Graduate School of Agriculture, Hokkaido University, Japan
| | - Tohru Hira
- Graduate School of Agriculture, Hokkaido University, Japan; Research Faculty of Agriculture, Hokkaido University, Japan.
| |
Collapse
|
6
|
A review on mechanisms of action of bioactive peptides against glucose intolerance and insulin resistance. FOOD SCIENCE AND HUMAN WELLNESS 2022. [DOI: 10.1016/j.fshw.2022.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
7
|
Brubaker PL. The Molecular Determinants of Glucagon-like Peptide Secretion by the Intestinal L cell. Endocrinology 2022; 163:6717959. [PMID: 36156130 DOI: 10.1210/endocr/bqac159] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Indexed: 11/19/2022]
Abstract
The intestinal L cell secretes a diversity of biologically active hormones, most notably the glucagon-like peptides, GLP-1 and GLP-2. The highly successful introduction of GLP-1-based drugs into the clinic for the treatment of patients with type 2 diabetes and obesity, and of a GLP-2 analog for patients with short bowel syndrome, has led to the suggestion that stimulation of the endogenous secretion of these peptides may serve as a novel therapeutic approach in these conditions. Situated in the intestinal epithelium, the L cell demonstrates complex relationships with not only circulating, paracrine, and neural regulators, but also ingested nutrients and other factors in the lumen, most notably the microbiota. The integrated input from these numerous secretagogues results in a variety of temporal patterns in L cell secretion, ranging from minutes to 24 hours. This review combines the findings of traditional, physiological studies with those using newer molecular approaches to describe what is known and what remains to be elucidated after 5 decades of research on the intestinal L cell and its secreted peptides, GLP-1 and GLP-2.
Collapse
Affiliation(s)
- Patricia L Brubaker
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| |
Collapse
|
8
|
Kamakura R, Raza GS, Sodum N, Lehto V, Kovalainen M, Herzig K. Colonic Delivery of Nutrients for Sustained and Prolonged Release of Gut Peptides: A Novel Strategy for Appetite Management. Mol Nutr Food Res 2022; 66:e2200192. [PMID: 35938221 PMCID: PMC9787473 DOI: 10.1002/mnfr.202200192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/17/2022] [Indexed: 12/30/2022]
Abstract
Obesity is one of the major global threats to human health and risk factors for cardiometabolic diseases and certain cancers. Glucagon-like peptide-1 (GLP-1) plays a major role in appetite and glucose homeostasis and recently the USFDA approved GLP-1 agonists for the treatment of obesity and type 2 diabetes. GLP-1 is secreted from enteroendocrine L-cells in the distal part of the gastrointestinal (GI) tract in response to nutrient ingestion. Endogenously released GLP-1 has a very short half-life of <2 min and most of the nutrients are absorbed before reaching the distal GI tract and colon, which hinders the use of nutritional compounds for appetite regulation. The review article focuses on nutrients that endogenously stimulate GLP-1 and peptide YY (PYY) secretion via their receptors in order to decrease appetite as preventive action. In addition, various delivery technologies such as pH-sensitive, mucoadhesive, time-dependent, and enzyme-sensitive systems for colonic targeting of nutrients delivery are described. Sustained colonic delivery of nutritional compounds could be one of the most promising approaches to prevent obesity and associated metabolic diseases by, e.g., sustained GLP-1 release.
Collapse
Affiliation(s)
- Remi Kamakura
- Research Unit of BiomedicineFaculty of Medicine, and Medical Research CenterUniversity of Oulu and Oulu University HospitalOulu90220Finland
| | - Ghulam Shere Raza
- Research Unit of BiomedicineFaculty of Medicine, and Medical Research CenterUniversity of Oulu and Oulu University HospitalOulu90220Finland
| | - Nalini Sodum
- Research Unit of BiomedicineFaculty of Medicine, and Medical Research CenterUniversity of Oulu and Oulu University HospitalOulu90220Finland
| | - Vesa‐Pekka Lehto
- Department of Applied PhysicsFaculty of Science and ForestryUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Miia Kovalainen
- Research Unit of BiomedicineFaculty of Medicine, and Medical Research CenterUniversity of Oulu and Oulu University HospitalOulu90220Finland
| | - Karl‐Heinz Herzig
- Research Unit of BiomedicineFaculty of Medicine, and Medical Research CenterUniversity of Oulu and Oulu University HospitalOulu90220Finland
- Department of Pediatric Gastroenterology and Metabolic DiseasesPediatric InstitutePoznan University of Medical SciencesPoznań60–572Poland
| |
Collapse
|
9
|
Investigation into Antiepileptic Effect of Ganoderic Acid A and Its Mechanism in Seizure Rats Induced by Pentylenetetrazole. BIOMED RESEARCH INTERNATIONAL 2022; 2022:5940372. [PMID: 36093409 PMCID: PMC9458365 DOI: 10.1155/2022/5940372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/07/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022]
Abstract
Ganoderic acid A (GAA) exhibited neuron protection in in vitro epilepsy study, but no study has been done in vivo. Rats were administered (i.p.) pentylenetetrazole daily for 28 days to induce seizure. Rats with grade II or above of epileptic score were divided into three groups and given placebo, sodium valproate, or GAA treatment, respectively, for 7 days. The electrical signals of brain were monitored with electroencephalography (EGG); epileptic behavior was assessed using the Racine scale; morphological changes and apoptosis rate of cortical neurons were assessed with H&E staining and TUNEL staining, respectively. Protein expression of calcium-sensing receptor, p-ERK, p-JNK, and p-p38 in hippocampal tissue and Bcl-2, cleaved caspase-3, and Bax in cortical tissues was observed by Western blot and immunohistochemistry assay, respectively. After GAA treatment, apparent seizure-like EEG with significant arrhythmic disorder and spike waves was reduced or disappeared, and wave amplitude of EEG was reduced significantly. GAA showed similar effect with sodium valproate treatments on epilepsy. There were an apparent improvement of the epileptic behavior and a significant increase in the epileptic latency and shortening of the epileptic duration in the treatment group compared to control. GAA treatment ameliorated the nuclear pyknosis of neurons which appeared seriously in the epilepsy group. GAA treatment significantly reduced the cortical neuron apoptosis of epilepsy and the expression of calcium-sensing receptor, p-P38, p-JNK, cleaved caspase-3, and Bax but increased the expression of both p-ERK and Bcl-2. In conclusion, GAA treatment showed strong antiepileptic effect by decreasing apoptosis in cortical neuron and the expression of calcium-sensing receptor and stimulating the MAPK pathway.
Collapse
|
10
|
Reboredo C, González-Navarro CJ, Martínez-López AL, Irache JM. Oral administration of zein-based nanoparticles reduces glycemia and improves glucose tolerance in rats. Int J Pharm 2022; 628:122255. [DOI: 10.1016/j.ijpharm.2022.122255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/24/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022]
|
11
|
Villegas-Novoa C, Wang Y, Sims CE, Allbritton NL. Development of a Primary Human Intestinal Epithelium Enriched in L-Cells for Assay of GLP-1 Secretion. Anal Chem 2022; 94:9648-9655. [PMID: 35758929 DOI: 10.1021/acs.analchem.2c00912] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes mellitus is a chronic disease associated with obesity and dysregulated human feeding behavior. The hormone glucagon-like peptide 1 (GLP-1), a critical regulator of body weight, food intake, and blood glucose levels, is secreted by enteroendocrine L-cells. The paucity of L-cells in primary intestinal cell cultures including organoids and monolayers has made assays of GLP-1 secretion from primary human cells challenging. In the current paper, an analytical assay pipeline consisting of an optimized human intestinal tissue construct enriched in L-cells paired with standard antibody-based GLP-1 assays was developed to screen compounds for the development of pharmaceuticals to modulate L-cell signaling. The addition of the serotonin receptor agonist Bimu 8, optimization of R-spondin and Noggin concentrations, and utilization of vasoactive intestinal peptide (VIP) increased the density of L-cells in a primary human colonic epithelial monolayer. Additionally, the incorporation of an air-liquid interface culture format increased the L-cell number so that the signal-to-noise ratio of conventional enzyme-linked immunoassays could be used to monitor GLP-1 secretion in compound screens. To demonstrate the utility of the optimized analytical method, 21 types of beverage sweeteners were screened for their ability to stimulate GLP-1 secretion. Stevioside and cyclamate were found to be the most potent inducers of GLP-1 secretion. This platform enables the quantification of GLP-1 secretion from human primary L-cells and will have broad application in understanding L-cell formation and physiology and will improve the identification of modulators of human feeding behavior.
Collapse
Affiliation(s)
- Cecilia Villegas-Novoa
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, United States
| | - Yuli Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, United States
| | | | - Nancy L Allbritton
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, United States
| |
Collapse
|
12
|
Lok KH, Wareham NJ, Nair RS, How CW, Chuah LH. Revisiting the concept of incretin and enteroendocrine L-cells as type 2 diabetes mellitus treatment. Pharmacol Res 2022; 180:106237. [PMID: 35487405 PMCID: PMC7614293 DOI: 10.1016/j.phrs.2022.106237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/08/2022] [Accepted: 04/22/2022] [Indexed: 12/19/2022]
Abstract
The significant growth in type 2 diabetes mellitus (T2DM) prevalence strikes a common threat to the healthcare and economic systems globally. Despite the availability of several anti-hyperglycaemic agents in the market, none can offer T2DM remission. These agents include the prominent incretin-based therapy such as glucagon-like peptide-1 receptor (GLP-1R) agonists and dipeptidyl peptidase-4 inhibitors that are designed primarily to promote GLP-1R activation. Recent interest in various therapeutically useful gastrointestinal hormones in T2DM and obesity has surged with the realisation that enteroendocrine L-cells modulate the different incretins secretion and glucose homeostasis, reflecting the original incretin definition. Targeting L-cells offers promising opportunities to mimic the benefits of bariatric surgery on glucose homeostasis, bodyweight management, and T2DM remission. Revising the fundamental incretin theory is an essential step for therapeutic development in this area. Therefore, the present review explores enteroendocrine L-cell hormone expression, the associated nutrient-sensing mechanisms, and other physiological characteristics. Subsequently, enteroendocrine L-cell line models and the latest L-cell targeted therapies are reviewed critically in this paper. Bariatric surgery, pharmacotherapy and new paradigm of L-cell targeted pharmaceutical formulation are discussed here, offering both clinician and scientist communities a new common interest to push the scientific boundary in T2DM therapy.
Collapse
Affiliation(s)
- Kok-Hou Lok
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Nicholas J Wareham
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia; MRC Epidemiology Unit, University of Cambridge, Institute of Metabolic Science, Cambridge, UK.
| | - Rajesh Sreedharan Nair
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Chee Wun How
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Lay-Hong Chuah
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| |
Collapse
|
13
|
Jahandideh F, Bourque SL, Wu J. A comprehensive review on the glucoregulatory properties of food-derived bioactive peptides. Food Chem X 2022; 13:100222. [PMID: 35498998 PMCID: PMC9039931 DOI: 10.1016/j.fochx.2022.100222] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/03/2022] [Accepted: 01/18/2022] [Indexed: 02/07/2023] Open
Abstract
Diabetes mellitus, a group of metabolic disorders characterized by persistent hyperglycemia, affects millions of people worldwide and is on the rise. Dietary proteins, from a wide range of food sources, are rich in bioactive peptides with antidiabetic properties. Notable examples include AGFAGDDAPR, a black tea-derived peptide, VRIRLLQRFNKRS, a β-conglycinin-derived peptide, and milk-derived peptide VPP, which have shown antidiabetic effects in diabetic rodent models through variety of pathways including improving beta-cells function, suppression of alpha-cells proliferation, inhibiting food intake, increasing portal cholecystokinin concentration, enhancing insulin signaling and glucose uptake, and ameliorating adipose tissue inflammation. Despite the immense research on glucoregulatory properties of bioactive peptides, incorporation of these bioactive peptides in functional foods or nutraceuticals is widely limited due to the existence of several challenges in the field of peptide research and commercialization. Ongoing research in this field, however, is fundamental to pave the road for this purpose.
Collapse
Key Words
- AMPK, AMP-activated protein kinase
- Akt, Protein kinase B
- Bioactive peptides
- C/EBP-α, CCAAT/ enhancer binding protein alpha
- CCK, Cholecystokinin
- CCK-1R, CCK type 1 receptor
- DPP-IV, Dipeptidyl peptidase IV
- Diabetes mellitus
- ERK1/2, Extracellular signal regulated kinase 1/2
- GIP, Glucose-dependent insulinotropic polypeptide
- GLP-1, Glucagon-like peptide 1
- GLUT, Glucose transporter
- Glucose homeostasis
- IRS-1, Insulin receptor substrate-1
- Insulin resistance
- MAPK, Mitogen activated protein kinase
- PI3K, Phosphatidylinositol 3-kinase
- PPARγ, Peroxisome proliferator associated receptor gamma
- Reproductive dysfunction
- TZD, Thiazolidinedione
- cGMP, cyclic guanosine-monophosphate
Collapse
Affiliation(s)
- Forough Jahandideh
- Department of Anesthesiology & Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2G3, Canada.,Cardiovascular Research Centre, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Stephane L Bourque
- Department of Anesthesiology & Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2G3, Canada.,Cardiovascular Research Centre, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Jianping Wu
- Cardiovascular Research Centre, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada.,Department of Agricultural, Food and Nutritional Science, Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada
| |
Collapse
|
14
|
Petersen N, Greiner TU, Torz L, Bookout A, Gerstenberg MK, Castorena CM, Kuhre RE. Targeting the Gut in Obesity: Signals from the Inner Surface. Metabolites 2022; 12:metabo12010039. [PMID: 35050161 PMCID: PMC8778595 DOI: 10.3390/metabo12010039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/26/2021] [Accepted: 12/31/2021] [Indexed: 12/17/2022] Open
Abstract
Obesity is caused by prolonged energy surplus. Current anti-obesity medications are mostly centralized around the energy input part of the energy balance equation by increasing satiety and reducing appetite. Our gastrointestinal tract is a key organ for regulation of food intake and supplies a tremendous number of circulating signals that modulate the activity of appetite-regulating areas of the brain by either direct interaction or through the vagus nerve. Intestinally derived messengers are manifold and include absorbed nutrients, microbial metabolites, gut hormones and other enterokines, collectively comprising a fine-tuned signalling system to the brain. After a meal, nutrients directly interact with appetite-inhibiting areas of the brain and induce satiety. However, overall feeding behaviour also depends on secretion of gut hormones produced by highly specialized and sensitive enteroendocrine cells. Moreover, circulating microbial metabolites and their interactions with enteroendocrine cells further contribute to the regulation of feeding patterns. Current therapies exploiting the appetite-regulating properties of the gut are based on chemically modified versions of the gut hormone, glucagon-like peptide-1 (GLP-1) or on inhibitors of the primary GLP-1 inactivating enzyme, dipeptidyl peptidase-4 (DPP-4). The effectiveness of these approaches shows that that the gut is a promising target for therapeutic interventions to achieve significant weigh loss. We believe that increasing understanding of the functionality of the intestinal epithelium and new delivery systems will help develop selective and safe gut-based therapeutic strategies for improved obesity treatment in the future. Here, we provide an overview of the major homeostatic appetite-regulating signals generated by the intestinal epithelial cells and how these signals may be harnessed to treat obesity by pharmacological means.
Collapse
Affiliation(s)
- Natalia Petersen
- Global Obesity and Liver Disease Research, Global Drug Discovery, Novo Nordisk A/S, Novo Park 1, 2670 Måløv, Denmark; (L.T.); (M.K.G.); (R.E.K.)
- Correspondence:
| | - Thomas U. Greiner
- The Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, 405 30 Gothenburg, Sweden;
| | - Lola Torz
- Global Obesity and Liver Disease Research, Global Drug Discovery, Novo Nordisk A/S, Novo Park 1, 2670 Måløv, Denmark; (L.T.); (M.K.G.); (R.E.K.)
- Department of Veterinary and Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Angie Bookout
- Global Obesity and Liver Disease Research, Global Drug Discovery, Novo Nordisk Research Center, Seattle, WA 98109, USA; (A.B.); (C.M.C.)
| | - Marina Kjærgaard Gerstenberg
- Global Obesity and Liver Disease Research, Global Drug Discovery, Novo Nordisk A/S, Novo Park 1, 2670 Måløv, Denmark; (L.T.); (M.K.G.); (R.E.K.)
| | - Carlos M. Castorena
- Global Obesity and Liver Disease Research, Global Drug Discovery, Novo Nordisk Research Center, Seattle, WA 98109, USA; (A.B.); (C.M.C.)
| | - Rune Ehrenreich Kuhre
- Global Obesity and Liver Disease Research, Global Drug Discovery, Novo Nordisk A/S, Novo Park 1, 2670 Måløv, Denmark; (L.T.); (M.K.G.); (R.E.K.)
- Department of Veterinary and Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| |
Collapse
|
15
|
Miedzybrodzka EL, Gribble FM, Reimann F. Targeting the Enteroendocrine System for Treatment of Obesity. Handb Exp Pharmacol 2022; 274:487-513. [PMID: 35419620 DOI: 10.1007/164_2022_583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mimetics of the anorexigenic gut hormone glucagon-like peptide 1 (GLP-1) were originally developed as insulinotropic anti-diabetic drugs but also evoke significant weight loss, leading to their recent approval as obesity therapeutics. Co-activation of receptors for GLP-1 and other gut hormones which reduce food intake - peptide YY (PYY3-36), cholecystokinin (CCK) and glucose-dependent insulinotropic peptide (GIP) - is now being explored clinically to enhance efficacy. An alternative approach involves pharmacologically stimulating endogenous secretion of these hormones from enteroendocrine cells (EECs) to recapitulate the metabolic consequences of bariatric surgery, where highly elevated postprandial levels of GLP-1 and PYY3-36 are thought to contribute to improved glycaemia and weight loss.
Collapse
Affiliation(s)
- Emily L Miedzybrodzka
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Fiona M Gribble
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
| | - Frank Reimann
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| |
Collapse
|
16
|
Nauck MA, Quast DR, Wefers J, Pfeiffer AFH. The evolving story of incretins (GIP and GLP-1) in metabolic and cardiovascular disease: A pathophysiological update. Diabetes Obes Metab 2021; 23 Suppl 3:5-29. [PMID: 34310013 DOI: 10.1111/dom.14496] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 11/27/2022]
Abstract
The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) have their main physiological role in augmenting insulin secretion after their nutrient-induced secretion from the gut. A functioning entero-insular (gut-endocrine pancreas) axis is essential for the maintenance of a normal glucose tolerance. This is exemplified by the incretin effect (greater insulin secretory response to oral as compared to "isoglycaemic" intravenous glucose administration due to the secretion and action of incretin hormones). GIP and GLP-1 have additive effects on insulin secretion. Local production of GIP and/or GLP-1 in islet α-cells (instead of enteroendocrine K and L cells) has been observed, and its significance is still unclear. GLP-1 suppresses, and GIP increases glucagon secretion, both in a glucose-dependent manner. GIP plays a greater physiological role as an incretin. In type 2-diabetic patients, the incretin effect is reduced despite more or less normal secretion of GIP and GLP-1. While insulinotropic effects of GLP-1 are only slightly impaired in type 2 diabetes, GIP has lost much of its acute insulinotropic activity in type 2 diabetes, for largely unknown reasons. Besides their role in glucose homoeostasis, the incretin hormones GIP and GLP-1 have additional biological functions: GLP-1 at pharmacological concentrations reduces appetite, food intake, and-in the long run-body weight, and a similar role is evolving for GIP, at least in animal studies. Human studies, however, do not confirm these findings. GIP, but not GLP-1 increases triglyceride storage in white adipose tissue not only through stimulating insulin secretion, but also by interacting with regional blood vessels and GIP receptors. GIP, and to a lesser degree GLP-1, play a role in bone remodelling. GLP-1, but not GIP slows gastric emptying, which reduces post-meal glycaemic increments. For both GIP and GLP-1, beneficial effects on cardiovascular complications and neurodegenerative central nervous system (CNS) disorders have been observed, pointing to therapeutic potential over and above improving diabetes complications. The recent finding that GIP/GLP-1 receptor co-agonists like tirzepatide have superior efficacy compared to selective GLP-1 receptor agonists with respect to glycaemic control as well as body weight has renewed interest in GIP, which previously was thought to be without any therapeutic potential. One focus of this research is into the long-term interaction of GIP and GLP-1 receptor signalling. A GLP-1 receptor antagonist (exendin [9-39]) and, more recently, a GIP receptor agonist (GIP [3-30] NH2 ) and, hopefully, longer-acting GIP receptor agonists for human use will be helpful tools to shed light on the open questions. A detailed knowledge of incretin physiology and pathophysiology will be a prerequisite for designing more effective incretin-based diabetes drugs.
Collapse
Affiliation(s)
- Michael A Nauck
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Daniel R Quast
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Jakob Wefers
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Andreas F H Pfeiffer
- Charité - Universitätsmedizin Berlin, Klinik für Endokrinologie, Stoffwechsel- und Ernährungsmedizin, Berlin, Germany
| |
Collapse
|
17
|
Characteristics of Food Protein-Derived Antidiabetic Bioactive Peptides: A Literature Update. Int J Mol Sci 2021; 22:ijms22179508. [PMID: 34502417 PMCID: PMC8431147 DOI: 10.3390/ijms22179508] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/29/2021] [Accepted: 08/30/2021] [Indexed: 12/25/2022] Open
Abstract
Diabetes, a glucose metabolic disorder, is considered one of the biggest challenges associated with a complex complication of health crises in the modern lifestyle. Inhibition or reduction of the dipeptidyl peptidase IV (DPP-IV), alpha-glucosidase, and protein-tyrosine phosphatase 1B (PTP-1B) enzyme activities or expressions are notably considered as the promising therapeutic strategies for the management of type 2 diabetes (T2D). Various food protein-derived antidiabetic bioactive peptides have been isolated and verified. This review provides an overview of the DPP-IV, PTP-1B, and α-glucosidase inhibitors, and updates on the methods for the discovery of DPP-IV inhibitory peptides released from food-protein hydrolysate. The finding of novel bioactive peptides involves studies about the strategy of separation fractionation, the identification of peptide sequences, and the evaluation of peptide characteristics in vitro, in silico, in situ, and in vivo. The potential of bioactive peptides suggests useful applications in the prevention and management of diabetes. Furthermore, evidence of clinical studies is necessary for the validation of these peptides’ efficiencies before commercial applications.
Collapse
|
18
|
Hira T, Trakooncharoenvit A, Taguchi H, Hara H. Improvement of Glucose Tolerance by Food Factors Having Glucagon-Like Peptide-1 Releasing Activity. Int J Mol Sci 2021; 22:6623. [PMID: 34205659 PMCID: PMC8235588 DOI: 10.3390/ijms22126623] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/17/2021] [Accepted: 06/17/2021] [Indexed: 12/14/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone released from enteroendocrine L cells in response to meal ingestion. GLP-1 receptor agonists and GLP-1 enhancers have been clinically employed to treat diabetes owing to their glucose-dependent insulin-releasing activity. The release of GLP-1 is primarily stimulated by macronutrients such as glucose and fatty acids, which are nutritionally indispensable; however, excessive intake of sugar and fat is responsible for the development of obesity and diabetes. Therefore, GLP-1 releasing food factors, such as dietary peptides and non-nutrients, are deemed desirable for improving glucose tolerance. Human and animal studies have revealed that dietary proteins/peptides have a potent effect on stimulating GLP-1 secretion. Studies in enteroendocrine cell models have shown that dietary peptides, amino acids, and phytochemicals, such as quercetin, can directly stimulate GLP-1 secretion. In our animal experiments, these food factors improved glucose metabolism and increased GLP-1 secretion. Furthermore, some dietary peptides not only stimulated GLP-1 secretion but also reduced plasma peptidase activity, which is responsible for GLP-1 inactivation. Herein, we review the relationship between GLP-1 and food factors, especially dietary peptides and flavonoids. Accordingly, utilization of food factors with GLP-1-releasing/enhancing activity is a promising strategy for preventing and treating obesity and diabetes.
Collapse
Affiliation(s)
- Tohru Hira
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan;
- School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan;
| | | | - Hayate Taguchi
- School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan;
| | - Hiroshi Hara
- Department of Food Science and Human Nutrition, Fuji Women’s University, Ishikari-shi 061-320, Japan;
| |
Collapse
|
19
|
Igarashi A, Ogasawara S, Takagi R, Okada K, Ito YM, Hara H, Hira T. Acute Oral Calcium Suppresses Food Intake Through Enhanced Peptide-YY Secretion Mediated by the Calcium-Sensing Receptor in Rats. J Nutr 2021; 151:1320-1328. [PMID: 33693689 DOI: 10.1093/jn/nxab013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/14/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Dietary calcium has been proposed to reduce appetite in human studies. Postprandial satiety is mainly controlled by gut hormones. However, the effect of calcium on appetite and the role of gut hormones remain unclear. OBJECTIVES We examined whether oral administration of calcium reduces food intake in rats and investigated the underlying mechanism. METHODS Male Sprague Dawley rats (8-12 wk old) were used after an overnight fastifffng. In a series of 2 trials with 1-wk interval between challenges, food intake was measured 0.5-24 h after oral gavage of a vehicle (saline containing 1.5% carboxymethyl cellulose) as the control treatment, or the vehicle containing various calcium compounds [calcium chloride (CaCl2), calcium carbonate, calcium lactate, in a random order] at 150 mg calcium/kg dose. A conditional taste aversion test was conducted. In separate experiments, plasma calcium and gut hormone concentrations were measured 15 or 30 min after oral administration of the calcium compounds. In anesthetized rats, portal peptide-YY (PYY) concentrations were measured after intraluminal administration of a liquid meal with or without additional calcium. RESULTS Oral CaCl2 reduced food intake acutely (30 min, ∼20%, P < 0.05) compared with control rats, without taste aversion. Plasma PYY concentration was higher (100%, P < 0.05) in CaCl2-preloaded rats than in control rats, 15 min after administration. In anesthetized rats, luminal meal + CaCl2 induced a 4-fold higher increase in plasma PYY than the control treatment did. Oral administration of a calcium-sensing receptor (CaSR) agonist suppressed food intake (∼30%, P < 0.05), but CaCl2 and CaSR agonist did not suppress food intake under treatment with a PYY receptor antagonist. Furthermore, the CaSR antagonist attenuated the effect of CaCl2 on food intake. CONCLUSIONS CaCl2 suppresses food intake partly by increasing CaSR-mediated PYY secretion in rats. Our findings could at least partially explain the satiating effect of calcium.
Collapse
Affiliation(s)
- Akiho Igarashi
- School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Shono Ogasawara
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Ryo Takagi
- Biostatistics Division, Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Japan
| | - Kazufumi Okada
- Biostatistics Division, Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Japan
| | - Yoichi M Ito
- Biostatistics Division, Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Japan
| | - Hiroshi Hara
- Faculty of Human Life Science, Fuji Women's University, Ishikari, Japan
| | - Tohru Hira
- School of Agriculture, Hokkaido University, Sapporo, Japan
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| |
Collapse
|
20
|
Novel Homozygous Inactivating Mutation in the PCSK1 Gene in an Infant with Congenital Malabsorptive Diarrhea. Genes (Basel) 2021; 12:genes12050710. [PMID: 34068683 PMCID: PMC8151971 DOI: 10.3390/genes12050710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/02/2021] [Accepted: 05/07/2021] [Indexed: 01/03/2023] Open
Abstract
Proprotein convertase 1/3 (PC1/3), encoded by the PCSK1 gene, is expressed in neuronal and (entero)endocrine cell types, where it cleaves and hence activates a number of protein precursors that play a key role in energy homeostasis. Loss-of-function mutations in PCSK1 cause a recessive complex endocrinopathy characterized by malabsorptive diarrhea and early-onset obesity. Despite the fact that neonatal malabsorptive diarrhea is observed in all patients, it has remained understudied. The aim of this study was to investigate the enteroendocrine pathologies in a male patient with congenital PCSK1 deficiency carrying the novel homozygous c.1034A>C (p.E345A) mutation. This patient developed malabsorptive diarrhea and metabolic acidosis within the first week of life, but rapid weight gain was observed after total parenteral nutrition, and he displayed high proinsulin levels and low adrenocorticotropin. In vitro analysis showed that the p.E345A mutation in PC1/3 resulted in a (near) normal autocatalytic proPC1/3 processing and only partially impaired PC1/3 secretion, but the processing of a substrate in trans was completely blocked. Immunohistochemical staining did not reveal changes in the proGIP/GIP and proglucagon/GLP-1 ratio in colonic tissue. Hence, we report a novel PCSK1 deficient patient who, despite neonatal malabsorptive diarrhea, showed a normal morphology in the small intestine.
Collapse
|
21
|
Modvig IM, Kuhre RE, Jepsen SL, Xu SFS, Engelstoft MS, Egerod KL, Schwartz TW, Ørskov C, Rosenkilde MM, Holst JJ. Amino acids differ in their capacity to stimulate GLP-1 release from the perfused rat small intestine and stimulate secretion by different sensing mechanisms. Am J Physiol Endocrinol Metab 2021; 320:E874-E885. [PMID: 33645250 DOI: 10.1152/ajpendo.00026.2021] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The aim of this study was to explore individual amino acid-stimulated GLP-1 responses and the underlying stimulatory mechanisms, as well as to identify the amino acid-sensing receptors involved in amino acid-stimulated GLP-1 release. Experiments were primarily based on isolated perfused rat small intestines, which have intact epithelial polarization allowing discrimination between luminal and basolateral mechanisms as well as quantitative studies of intestinal absorption and hormone secretion. Expression analysis of amino acid sensors on isolated murine GLP-1 secreting L-cells was assessed by qPCR. We found that l-valine powerfully stimulated GLP-1 secretion but only from the luminal side (2.9-fold increase). When administered from the vascular side, l-arginine and the aromatic amino acids stimulated GLP-1 secretion equally (2.6- to 2.9-fold increases). Expression analysis revealed that Casr expression was enriched in murine GLP-1 secreting L-cells, whereas Gpr35, Gprc6a, Gpr142, Gpr93 (Lpar5), and the umami taste receptor subunits Tas1r3 and Tas1r1 were not. Consistently, activation of GPR35, GPR93, GPR142, and the umami taste receptor with specific agonists or allosteric modulators did not increase GLP-1 secretion (P > 0.05 for all experiments), whereas vascular inhibition of CaSR reduced GLP-1 secretion in response to luminal infusion of mixed amino acids. In conclusion, amino acids differ in their capacity to stimulate GLP-1 secretion. Some amino acids stimulated secretion only from the intestinal lumen, whereas other amino acids exclusively stimulated secretion from the vascular side, indicating that amino acid-stimulated GLP-1 secretion involves both apical and basolateral (postabsorptive) sensing mechanisms. Sensing of absorbed amino acids involves CaSR activation as vascular inhibition of CaSR markedly diminished amino acid stimulated GLP-1 release.NEW & NOTEWORTHY Using isolated perfused rat small intestines, we show that amino acids differ in their mechanisms and capacity of stimulating GLP-1 release. Furthermore, we demonstrate that sensing by GPR142, GPR35, GPR93, and the umami taste receptor (Tas1R1/Tas1R3) are not involved in amino acid stimulated GLP-1 release. In contrast to previous studies, this experimental model allows discrimination between the luminal and the vascular side of the intestine, which is essential when studying mechanisms of amino acid-stimulated GLP-1 secretion.
Collapse
MESH Headings
- Amino Acids/pharmacology
- Animals
- Glucagon-Like Peptide 1/metabolism
- Intestine, Small/drug effects
- Intestine, Small/metabolism
- Intestine, Small/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Perfusion
- Rats
- Rats, Wistar
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Lysophosphatidic Acid/agonists
- Receptors, Lysophosphatidic Acid/metabolism
- Secretory Pathway/drug effects
- Signal Transduction/drug effects
Collapse
Affiliation(s)
- Ida Marie Modvig
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rune Ehrenreich Kuhre
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara Lind Jepsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stella Feng Sheng Xu
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maja Storm Engelstoft
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer Lihme Egerod
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thue Walther Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
22
|
Yang M, Reimann F, Gribble FM. Chemosensing in enteroendocrine cells: mechanisms and therapeutic opportunities. Curr Opin Endocrinol Diabetes Obes 2021; 28:222-231. [PMID: 33449572 DOI: 10.1097/med.0000000000000614] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE OF REVIEW Enteroendocrine cells (EECs) are scattered chemosensory cells in the intestinal epithelium that release hormones with a wide range of actions on intestinal function, food intake and glucose homeostasis. The mechanisms by which gut hormones are secreted postprandially, or altered by antidiabetic agents and surgical interventions are of considerable interest for future therapeutic development. RECENT FINDINGS EECs are electrically excitable and express a repertoire of G-protein coupled receptors that sense nutrient and nonnutrient stimuli, coupled to intracellular Ca2+ and cyclic adenosine monophosphate. Our knowledge of EEC function, previously developed using mouse models, has recently been extended to human cells. Gut hormone release in humans is enhanced by bariatric surgery, as well as by some antidiabetic agents including sodium-coupled glucose transporter inhibitors and metformin. SUMMARY EECs are important potential therapeutic targets. A better understanding of their chemosensory mechanisms will enhance the development of new therapeutic strategies to treat metabolic and gastrointestinal diseases.
Collapse
Affiliation(s)
- Ming Yang
- University of Cambridge, Institute of Metabolic Science and MRC Metabolic Diseases Unit, Addenbrooke's Hospital, Cambridge, UK
| | | | | |
Collapse
|
23
|
Lu VB, Gribble FM, Reimann F. Nutrient-Induced Cellular Mechanisms of Gut Hormone Secretion. Nutrients 2021; 13:nu13030883. [PMID: 33803183 PMCID: PMC8000029 DOI: 10.3390/nu13030883] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/27/2021] [Accepted: 03/05/2021] [Indexed: 02/06/2023] Open
Abstract
The gastrointestinal tract can assess the nutrient composition of ingested food. The nutrient-sensing mechanisms in specialised epithelial cells lining the gastrointestinal tract, the enteroendocrine cells, trigger the release of gut hormones that provide important local and central feedback signals to regulate nutrient utilisation and feeding behaviour. The evidence for nutrient-stimulated secretion of two of the most studied gut hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), along with the known cellular mechanisms in enteroendocrine cells recruited by nutrients, will be the focus of this review. The mechanisms involved range from electrogenic transporters, ion channel modulation and nutrient-activated G-protein coupled receptors that converge on the release machinery controlling hormone secretion. Elucidation of these mechanisms will provide much needed insight into postprandial physiology and identify tractable dietary approaches to potentially manage nutrition and satiety by altering the secreted gut hormone profile.
Collapse
|
24
|
Abstract
Glucagon-Like Peptide-1 (GLP-1) is an important peptide hormone secreted by L-cells in the gastrointestinal tract in response to nutrients. It is produced by the differential cleavage of the proglucagon peptide. GLP-1 elicits a wide variety of physiological responses in many tissues that contribute to metabolic homeostasis. For these reasons, therapies designed to either increase endogenous GLP-1 levels or introduce exogenous peptide mimetics are now widely used in the management of diabetes. In addition to GLP-1 production from L-cells, recent reports suggest that pancreatic islet alpha cells may also synthesize and secrete GLP-1. Intra-islet GLP-1 may therefore play an unappreciated role in islet health and glucose regulation, suggesting a potential functional paracrine role for islet-derived GLP-1. In this review, we assess the current literature from an islet-centric point-of-view to better understand the production, degradation, and actions of GLP-1 within the endocrine pancreas in rodents and humans. The relevance of intra-islet GLP-1 in human physiology is discussed regarding the potential role of intra-islet GLP-1 in islet health and dysfunction.
Collapse
Affiliation(s)
- Scott A. Campbell
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal Diabetes Research Centre CRCHUM, Montréal, Canada
| | - Janyne Johnson
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Peter E. Light
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- CONTACT Peter E. Light Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2E1, Canada
| |
Collapse
|
25
|
Abstract
Glucagon-like peptide-1 (GLP-1) is an enterohormone with a key role in several processes controlling body homeostasis, including glucose homeostasis and food intake regulation. It is secreted by the intestinal cells in response to nutrients, such as glucose, fat and amino acids. In the present review, we analyse the effect of protein on GLP-1 secretion and clearance. We review the literature on the GLP-1 secretory effects of protein and protein hydrolysates, and the mechanisms through which they exert these effects. We also review the studies on protein from different sources that has inhibitory effects on dipeptidyl peptidase-4 (DPP4), the enzyme responsible for GLP-1 inactivation, with particular emphasis on specific sources and treatments, and the gaps there still are in knowledge. There is evidence that the protein source and the hydrolytic processing applied to them can influence the effects on GLP-1 signalling. The gastrointestinal digestion of proteins, for example, significantly changes their effectiveness at modulating this enterohormone secretion in both in vivo and in vitro studies. Nevertheless, little information is available regarding human studies and more research is required to understand their potential as regulators of glucose homeostasis.
Collapse
|
26
|
Kuhre RE, Deacon CF, Holst JJ, Petersen N. What Is an L-Cell and How Do We Study the Secretory Mechanisms of the L-Cell? Front Endocrinol (Lausanne) 2021; 12:694284. [PMID: 34168620 PMCID: PMC8218725 DOI: 10.3389/fendo.2021.694284] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 05/11/2021] [Indexed: 12/14/2022] Open
Abstract
Synthetic glucagon-like peptide-1 (GLP-1) analogues are effective anti-obesity and anti-diabetes drugs. The beneficial actions of GLP-1 go far beyond insulin secretion and appetite, and include cardiovascular benefits and possibly also beneficial effects in neurodegenerative diseases. Considerable reserves of GLP-1 are stored in intestinal endocrine cells that potentially might be mobilized by pharmacological means to improve the body's metabolic state. In recognition of this, the interest in understanding basic L-cell physiology and the mechanisms controlling GLP-1 secretion, has increased considerably. With a view to home in on what an L-cell is, we here present an overview of available data on L-cell development, L-cell peptide expression profiles, peptide production and secretory patterns of L-cells from different parts of the gut. We conclude that L-cells differ markedly depending on their anatomical location, and that the traditional definition of L-cells as a homogeneous population of cells that only produce GLP-1, GLP-2, glicentin and oxyntomodulin is no longer tenable. We suggest to sub-classify L-cells based on their differential peptide contents as well as their differential expression of nutrient sensors, which ultimately determine the secretory responses to different stimuli. A second purpose of this review is to describe and discuss the most frequently used experimental models for functional L-cell studies, highlighting their benefits and limitations. We conclude that no experimental model is perfect and that a comprehensive understanding must be built on results from a combination of models.
Collapse
Affiliation(s)
- Rune E. Kuhre
- Department of Obesity Pharmacology, Novo Nordisk, Måløv, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Rune E. Kuhre, ;
| | - Carolyn F. Deacon
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
- School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
| | - Jens J. Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | | |
Collapse
|
27
|
Chanpaisaeng K, Teerapornpuntakit J, Wongdee K, Charoenphandhu N. Emerging roles of calcium-sensing receptor in the local regulation of intestinal transport of ions and calcium. Am J Physiol Cell Physiol 2020; 320:C270-C278. [PMID: 33356945 DOI: 10.1152/ajpcell.00485.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Whether the intestinal mucosal cells are capable of sensing calcium concentration in the lumen and pericellular interstitium remains enigmatic for decades. Most calcium-regulating organs, such as parathyroid gland, kidney, and bone, are capable of using calcium-sensing receptor (CaSR) to detect plasma calcium and trigger appropriate feedback responses to maintain calcium homeostasis. Although both CaSR transcripts and proteins are abundantly expressed in the crypt and villous enterocytes of the small intestine as well as the surface epithelial cells of the large intestine, the studies of CaSR functions have been limited to amino acid sensing and regulation of epithelial fluid secretion. Interestingly, several lines of recent evidence have indicated that the enterocytes use CaSR to monitor luminal and extracellular calcium levels, thereby reducing the activity of transient receptor potential channel, subfamily V, member 6, and inducing paracrine and endocrine feedback responses to restrict calcium absorption. Recent investigations in zebra fish and rodents have also suggested the role of fibroblast growth factor (FGF)-23 as an endocrine and/or paracrine factor participating in the negative control of intestinal calcium transport. In this review article, besides the CaSR-modulated ion transport, we elaborate the possible roles of CaSR and FGF-23 as well as their crosstalk as parts of a negative feedback loop for counterbalancing the seemingly unopposed calciotropic effect of 1,25-dihydroxyvitamin D3 on the intestinal calcium absorption.
Collapse
Affiliation(s)
- Krittikan Chanpaisaeng
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Kannikar Wongdee
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Faculty of Allied Health Sciences, Burapha University, Chonburi, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.,The Academy of Science, The Royal Society of Thailand, Bangkok, Thailand
| |
Collapse
|
28
|
Nunez-Salces M, Li H, Feinle-Bisset C, Young RL, Page AJ. Nutrient-sensing components of the mouse stomach and the gastric ghrelin cell. Neurogastroenterol Motil 2020; 32:e13944. [PMID: 32666613 DOI: 10.1111/nmo.13944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/22/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND The ability of the gut to detect nutrients is critical to the regulation of gut hormone secretion, food intake, and postprandial blood glucose control. Ingested nutrients are detected by specific gut chemosensors. However, knowledge of these chemosensors has primarily been derived from the intestine, while available information on gastric chemosensors is limited. This study aimed to investigate the nutrient-sensing repertoire of the mouse stomach with particular emphasis on ghrelin cells. METHODS Quantitative RT-PCR was used to determine mRNA levels of nutrient chemosensors (protein: G protein-coupled receptor 93 [GPR93], calcium-sensing receptor [CaSR], metabotropic glutamate receptor type 4 [mGluR4]; fatty acids: CD36, FFAR2&4; sweet/umami taste: T1R3), taste transduction components (TRPM5, GNAT2&3), and ghrelin and ghrelin-processing enzymes (PC1/3, ghrelin O-acyltransferase [GOAT]) in the gastric corpus and antrum of adult male C57BL/6 mice. Immunohistochemistry was performed to assess protein expression of chemosensors (GPR93, T1R3, CD36, and FFAR4) and their co-localization with ghrelin. KEY RESULTS Most nutrient chemosensors had higher mRNA levels in the antrum compared to the corpus, except for CD36, GNAT2, ghrelin, and GOAT. Similar regional distribution was observed at the protein level. At least 60% of ghrelin-positive cells expressed T1R3 and FFAR4, and over 80% expressed GPR93 and CD36. CONCLUSIONS AND INFERENCES The cellular mechanisms for the detection of nutrients are expressed in a region-specific manner in the mouse stomach and gastric ghrelin cells. These gastric nutrient chemosensors may play a role modulating gastrointestinal responses, such as the inhibition of ghrelin secretion following food intake.
Collapse
Affiliation(s)
- Maria Nunez-Salces
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Hui Li
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Christine Feinle-Bisset
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Richard L Young
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia.,Intestinal Nutrient Sensing Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| |
Collapse
|
29
|
Enteroendocrine Hormone Secretion and Metabolic Control: Importance of the Region of the Gut Stimulation. Pharmaceutics 2020; 12:pharmaceutics12090790. [PMID: 32825608 PMCID: PMC7559385 DOI: 10.3390/pharmaceutics12090790] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/19/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022] Open
Abstract
It is now widely appreciated that gastrointestinal function is central to the regulation of metabolic homeostasis. Following meal ingestion, the delivery of nutrients from the stomach into the small intestine (i.e., gastric emptying) is tightly controlled to optimise their subsequent digestion and absorption. The complex interaction of intraluminal nutrients (and other bioactive compounds, such as bile acids) with the small and large intestine induces the release of an array of gastrointestinal hormones from specialised enteroendocrine cells (EECs) distributed in various regions of the gut, which in turn to regulate gastric emptying, appetite and postprandial glucose metabolism. Stimulation of gastrointestinal hormone secretion, therefore, represents a promising strategy for the management of metabolic disorders, particularly obesity and type 2 diabetes mellitus (T2DM). That EECs are distributed distinctively between the proximal and distal gut suggests that the region of the gut exposed to intraluminal stimuli is of major relevance to the secretion profile of gastrointestinal hormones and associated metabolic responses. This review discusses the process of intestinal digestion and absorption and their impacts on the release of gastrointestinal hormones and the regulation of postprandial metabolism, with an emphasis on the differences between the proximal and distal gut, and implications for the management of obesity and T2DM.
Collapse
|
30
|
Leach K, Hannan FM, Josephs TM, Keller AN, Møller TC, Ward DT, Kallay E, Mason RS, Thakker RV, Riccardi D, Conigrave AD, Bräuner-Osborne H. International Union of Basic and Clinical Pharmacology. CVIII. Calcium-Sensing Receptor Nomenclature, Pharmacology, and Function. Pharmacol Rev 2020; 72:558-604. [PMID: 32467152 PMCID: PMC7116503 DOI: 10.1124/pr.119.018531] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.
Collapse
Affiliation(s)
- Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Fadil M Hannan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Thor C Møller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Donald T Ward
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Enikö Kallay
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rebecca S Mason
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rajesh V Thakker
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Daniela Riccardi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Hans Bräuner-Osborne
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| |
Collapse
|
31
|
Kim JH, Lee JO, Moon JW, Kang MJ, Byun WS, Han JA, Kim SJ, Park SH, Kim HS. Laminarin From Salicornia herbacea Stimulates Glucose Uptake Through AMPK-p38 MAPK Pathways in L6 Muscle Cells. Nat Prod Commun 2020. [DOI: 10.1177/1934578x20901409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Laminarin is a component of brown seaweed, especially isolated from Salicornia herbacea. Laminarin was known to have various physiological functions, however, the molecular mechanism is still unclear. In this study, we report that laminarin stimulates an activation of AMP-activated protein kinase (AMPK) and increases glucose uptake in rat L6 myotubes. Laminarin also increases an intracellular calcium release. Inhibition of Ca2+ release, using with CaMKK inhibitor, STO-609, blocked laminarin-induced AMPK activity, indicating that laminarin stimulated AMPK activity via calcium. In addition, laminarin activates p38 mitogen-activated protein kinase (MAPK) signaling pathways depending on AMPK activity. Moreover, the inhibition of either AMPK or p38 MAPK blocked laminarin-induced glucose uptake in rat L6 myotubes. Taken together, these results demonstrate that the hypoglycemic effect of laminarin is caused by its ability to activate AMPK-p38 MAPK pathways in skeletal muscles.
Collapse
Affiliation(s)
- Ji H. Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jung O. Lee
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Ji W. Moon
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Min J. Kang
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Won S. Byun
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jeong A. Han
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Su J. Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Sun H. Park
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Hyeon S. Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
32
|
Reimann F, Diakogiannaki E, Hodge D, Gribble FM. Cellular mechanisms governing glucose-dependent insulinotropic polypeptide secretion. Peptides 2020; 125:170206. [PMID: 31756367 DOI: 10.1016/j.peptides.2019.170206] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 02/01/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone secreted from the upper small intestine, which plays an important physiological role in the control of glucose metabolism through its incretin action to enhance glucose-dependent insulin secretion. GIP has also been implicated in postprandial lipid homeostasis. GIP is secreted from enteroendocrine K-cells residing in the intestinal epithelium. K-cells sense a variety of components found in the gut lumen following food consumption, resulting in an increase in plasma GIP signal dependent on the nature and quantity of ingested nutrients. We review the evidence for an important role of sodium-coupled glucose uptake through SGLT1 for carbohydrate sensing, of free-fatty acid receptors FFAR1/FFAR4 and the monoacyl-glycerol sensing receptor GPR119 for lipid detection, of the calcium-sensing receptor CASR and GPR142 for protein sensing, and additional modulation by neurotransmitters such as somatostatin and galanin. These pathways have been identified through combinations of in vivo, in vitro and molecular approaches.
Collapse
Affiliation(s)
- Frank Reimann
- Wellcome Trust/MRC Institute of Metabolic Science (IMS), University of Cambridge, United Kingdom.
| | - Eleftheria Diakogiannaki
- Wellcome Trust/MRC Institute of Metabolic Science (IMS), University of Cambridge, United Kingdom
| | - Daryl Hodge
- Wellcome Trust/MRC Institute of Metabolic Science (IMS), University of Cambridge, United Kingdom
| | - Fiona M Gribble
- Wellcome Trust/MRC Institute of Metabolic Science (IMS), University of Cambridge, United Kingdom.
| |
Collapse
|
33
|
Wang H, Murthy KS, Grider JR. Expression patterns of L-amino acid receptors in the murine STC-1 enteroendocrine cell line. Cell Tissue Res 2019; 378:471-483. [PMID: 31410629 DOI: 10.1007/s00441-019-03074-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022]
Abstract
Regulation of gut function depends on the detection and response to luminal contents. Luminal L-amino acids (L-AA) are detected by several receptors including metabotropic glutamate receptors 1 and 4 (mGluR1 and mGluR4), calcium-sensing receptor (CaSR), GPRC family C group 6 subtype A receptor (GPRC6A) and umami taste receptor heterodimer T1R1/T1R3. Here, we show that murine mucosal homogenates and STC-1 cells, a murine enteroendocrine cell line, express mRNA for all L-AA receptors. Immunohistochemical analysis demonstrated the presence of all L-AA receptors on STC-1 with CaSR being most commonly expressed and T1R1 least expressed (35% versus 15% of cells); mGluRs and GPRC6a were intermediate (~ 20% of cells). Regarding coexpression of L-AA receptors, the mGluRs and T1R1 were similarly coexpressed with CaSR (10-12% of cells) whereas GPRC6a was coexpressed least (7% of cells). mGluR1 was coexpressed with GPRC6a in 11% of cells whereas coexpression between other receptors was less (2-8% of cells). CaSR and mGluR1 were coexpressed with glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in 20-25% of cells whereas T1R1 and GPRC6a were coexpressed with GLP-1 and PYY less (8-12% of cells). Only mGluR4 showed differential coexpression with GLP-1 (13%) and PYY (21%). L-Phenylalanine (10 mM) caused a 3-fold increase in GLP-1 release, which was strongly inhibited by siRNA to CaSR indicating functional coupling of CaSR to GLP-1 release. The results suggest that not all STC-1 cells express (and coexpress) L-AA receptors to the same extent and that the pattern of response likely depends on the pattern of expression of L-AA receptors.
Collapse
Affiliation(s)
- Hongxia Wang
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA
| | - Karnam S Murthy
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA
| | - John R Grider
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA.
| |
Collapse
|
34
|
Modvig IM, Kuhre RE, Holst JJ. Peptone-mediated glucagon-like peptide-1 secretion depends on intestinal absorption and activation of basolaterally located Calcium-Sensing Receptors. Physiol Rep 2019; 7:e14056. [PMID: 31020803 PMCID: PMC6482282 DOI: 10.14814/phy2.14056] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/15/2019] [Accepted: 03/16/2019] [Indexed: 01/13/2023] Open
Abstract
Protein intake robustly stimulates the secretion of the incretin hormone, glucagon-like peptide-1 (GLP-1) but the molecular mechanisms involved are not well understood. In particular, it is unknown whether proteins stimulate secretion by activation of luminal or basolateral sensors. We characterized the mechanisms using a physiologically relevant model - the isolated perfused proximal rat small intestine. Intraluminal protein hydrolysates derived from meat (peptone; 50 mg/mL) increased GLP-1 secretion 2.3-fold (from a basal secretion of 110 ± 28 fmol/min). The sensory mechanisms underlying the response depended on di/tripeptide uptake through Peptide Transporter 1 (PepT1) and subsequent basolateral activation of the amino acid sensing receptor, Calcium-Sensing Receptor (CaSR), since inhibition of PepT1 as well as CaSR both attenuated the peptone-induced GLP-1 response. Supporting this, intraluminal peptones were absorbed efficiently by the perfused intestine (resulting in increased amino acid concentrations in the venous effluent) and infusion of amino acids robustly stimulated GLP-1 secretion. Inhibitors of voltage-gated L-type Ca2+ channels had no effect on secretion suggesting that peptone-mediated GLP-1 secretion is not mediated by L-cell depolarization with subsequent opening of these channels. Specific targeting of CaSR could serve as a target to stimulate the endogenous secretion of GLP-1.
Collapse
Affiliation(s)
- Ida M. Modvig
- Department of Biomedical SciencesNNF Center for Basic Metabolic ResearchFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Rune E. Kuhre
- Department of Biomedical SciencesNNF Center for Basic Metabolic ResearchFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Jens Juul Holst
- Department of Biomedical SciencesNNF Center for Basic Metabolic ResearchFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| |
Collapse
|
35
|
Abstract
Gut hormones have many key roles in the control of metabolism, as they target diverse tissues involved in the control of intestinal function, insulin secretion, nutrient assimilation and food intake. Produced by scattered cells found along the length of the intestinal epithelium, gut hormones generate signals related to the rate of nutrient absorption, the composition of the luminal milieu and the integrity of the epithelial barrier. Gut hormones already form the basis for existing and developing therapeutics for type 2 diabetes mellitus and obesity, exemplified by the licensed glucagon-like peptide 1 (GLP1) mimetics and dipeptidyl peptidase inhibitors that enhance GLP1 receptor activation. Modulating the release of the endogenous stores of GLP1 and other gut hormones is thought to be a promising strategy to mimic bariatric surgery with its multifaceted beneficial effects on food intake, body weight and blood glucose levels. This Review focuses on the molecular mechanisms underlying the modulation of gut hormone release by food ingestion, obesity and the gut microbiota. Depending on the nature of the stimulus, release of gut hormones involves recruitment of a variety of signalling pathways, including G protein-coupled receptors, nutrient transporters and ion channels, which are targets for future therapeutics for diabetes mellitus and obesity.
Collapse
Affiliation(s)
- Fiona M Gribble
- Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Frank Reimann
- Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| |
Collapse
|
36
|
Komatsu Y, Wada Y, Izumi H, Shimizu T, Takeda Y, Hira T, Hara H. Casein materials show different digestion patterns using an in vitro gastrointestinal model and different release of glucagon-like peptide-1 by enteroendocrine GLUTag cells. Food Chem 2018; 277:423-431. [PMID: 30502166 DOI: 10.1016/j.foodchem.2018.10.123] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 01/22/2023]
Abstract
Physicochemical properties of casein (CN) materials manufactured using different processes are well studied; however, data on their bioaccessibility or bioactivity are limited. We compared the digestion patterns and glucagon-like peptide-1 (GLP-1)-releasing activities of micellar CN concentrate (MCC) and sodium caseinate (SCN). MCC and SCN mixed with whey protein isolate (SCN + WPI) were subjected to in vitro gastrointestinal digestion; the digestibility of MCC was higher than that of SCN + WPI, and both CN materials showed different patterns of peptides released after in vitro digestion. A comparison of GLP-1-releasing activities showed that MCC induced GLP-1 secretion to a greater extent than SCN + WPI. Candidate peptides identified from CN digesta were chemically synthesized to test their GLP-1-releasing activity. GPVRGPFPIIV identified only in the MCC digesta, could stimulate GLP-1 release. In conclusion, the digestion patterns and GLP-1-releasing activity of CN materials depend on the production process.
Collapse
Affiliation(s)
- Yosuke Komatsu
- Wellness & Nutrition Science Institute, Morinaga Milk Industry Co., Ltd., 5-1-83 Higashihara, Zama, Kanagawa 252-8583, Japan; Center for Food and Medical Innovation Promotion, Institute for the Promotion of Business-Regional Collaboration of Hokkaido University, Kita-21, Nishi-11, Kita-ku, Sapporo, Hokkaido 001-0021, Japan.
| | - Yasuaki Wada
- Wellness & Nutrition Science Institute, Morinaga Milk Industry Co., Ltd., 5-1-83 Higashihara, Zama, Kanagawa 252-8583, Japan; Center for Food and Medical Innovation Promotion, Institute for the Promotion of Business-Regional Collaboration of Hokkaido University, Kita-21, Nishi-11, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
| | - Hirohisa Izumi
- Wellness & Nutrition Science Institute, Morinaga Milk Industry Co., Ltd., 5-1-83 Higashihara, Zama, Kanagawa 252-8583, Japan; Center for Food and Medical Innovation Promotion, Institute for the Promotion of Business-Regional Collaboration of Hokkaido University, Kita-21, Nishi-11, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
| | - Takashi Shimizu
- Wellness & Nutrition Science Institute, Morinaga Milk Industry Co., Ltd., 5-1-83 Higashihara, Zama, Kanagawa 252-8583, Japan
| | - Yasuhiro Takeda
- Wellness & Nutrition Science Institute, Morinaga Milk Industry Co., Ltd., 5-1-83 Higashihara, Zama, Kanagawa 252-8583, Japan
| | - Tohru Hira
- Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Hiroshi Hara
- Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| |
Collapse
|
37
|
Acar I, Cetinkaya A, Lay I, Ileri-Gurel E. The role of calcium sensing receptors in GLP-1 and PYY secretion after acute intraduodenal administration of L-Tryptophan in rats. Nutr Neurosci 2018; 23:481-489. [PMID: 30222528 DOI: 10.1080/1028415x.2018.1521906] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Objectives: The calcium-sensing receptor (CaSR), the major sensor of extracellular Ca2+, is expressed in various tissues, including the gastrointestinal tract. Although the essential ligand of CaSR is calcium, its activity can be regulated by aromatic L-amino acids. The expression of CaSR on enteroendocrine cells suggests that CaSR functions as a physiological amino acid sensor for gut hormone release. Here, we investigated the effects of L-tryptophan (L-Trp) on rat glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and insulin secretion, and the role of CaSR in this mechanism in vivo.Methods: The effects of intraduodenal L-Trp on GLP-1, PYY, and insulin secretion were investigated. A CaSR antagonist, NPS 2143, was administered to determine whether CaSR plays a role in L-Trp-mediated gut hormone release. Male Wistar rats were divided into L-Trp, L-Trp+NPS 2143, and L-Trp+vehicle groups. Blood samples were collected, before and after the intraduodenal infusions, for determining plasma glucose, L-Trp, insulin, GLP-1, and PYY levels.Results: Our study showed a significant increase in plasma GLP-1 and insulin levels, but not plasma PYY and glucose levels, following the acute intraduodenal administration of L-Trp. We demonstrated that CaSR plays a role in L-Trp-mediated GLP-1 secretion due to attenuation of GLP-1 release with the CaSR antagonist NPS 2143.Discussion: We demonstrated that GLP-1, but not PYY, secretion following intraduodenal L-Trp administration was mediated through calcium-sensing receptors. This mechanism underlying protein sensing in the gastrointestinal system may be important for the development of new therapeutic strategies without side effects for obesity and diabetes.
Collapse
Affiliation(s)
- Ipek Acar
- Physiology Department, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Alper Cetinkaya
- Laboratory Animals Research and Application Center, Hacettepe University, Ankara, Turkey
| | - Incilay Lay
- Medical Biochemistry Department, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Esin Ileri-Gurel
- Physiology Department, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| |
Collapse
|
38
|
Adriaenssens AE, Reimann F, Gribble FM. Distribution and Stimulus Secretion Coupling of Enteroendocrine Cells along the Intestinal Tract. Compr Physiol 2018; 8:1603-1638. [DOI: 10.1002/cphy.c170047] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
39
|
Billing LJ, Smith CA, Larraufie P, Goldspink DA, Galvin S, Kay RG, Howe JD, Walker R, Pruna M, Glass L, Pais R, Gribble FM, Reimann F. Co-storage and release of insulin-like peptide-5, glucagon-like peptide-1 and peptideYY from murine and human colonic enteroendocrine cells. Mol Metab 2018; 16:65-75. [PMID: 30104166 PMCID: PMC6158034 DOI: 10.1016/j.molmet.2018.07.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/20/2018] [Accepted: 07/24/2018] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE Insulin-like peptide-5 (INSL5) is an orexigenic gut hormone found in a subset of colonic and rectal enteroendocrine L-cells together with the anorexigenic hormones glucagon-like peptide-1 (GLP-1) and peptideYY (PYY). Unlike GLP-1 and PYY, INSL5 levels are elevated by calorie restriction, raising questions about how these hormones respond to different stimuli when they arise from the same cell type. The aim of the current study was to identify whether and how INSL5, GLP-1 and PYY are co-secreted or differentially secreted from colonic L-cells. METHODS An inducible reporter mouse (Insl5-rtTA) was created to enable selective characterisation of Insl5-expressing cells. Expression profiling and Ca2+-dynamics were assessed using TET-reporter mice. Secretion of INSL5, PYY, and GLP-1 from murine and human colonic crypt cultures was quantified by tandem mass spectrometry. Vesicular co-localisation of the three hormones was analysed in 3D-SIM images of immunofluorescently-labelled murine colonic primary cultures and tissue sections. RESULTS INSL5-producing cells expressed a range of G-protein coupled receptors previously identified in GLP-1 expressing L-cells, including Ffar1, Gpbar1, and Agtr1a. Pharmacological or physiological agonists for these receptors triggered Ca2+ transients in INSL5-producing cells and stimulated INSL5 secretion. INSL5 secretory responses strongly correlated with those of PYY and GLP-1 across a range of stimuli. The majority (>80%) of secretory vesicles co-labelled for INSL5, PYY and GLP-1. CONCLUSIONS INSL5 is largely co-stored with PYY and GLP-1 and all three hormones are co-secreted when INSL5-positive cells are stimulated. Opposing hormonal profiles observed in vivo likely reflect differential stimulation of L-cells in the proximal and distal gut.
Collapse
Affiliation(s)
- Lawrence J Billing
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Christopher A Smith
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Pierre Larraufie
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Deborah A Goldspink
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Sam Galvin
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Richard G Kay
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | | | - Ryan Walker
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Mihai Pruna
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Leslie Glass
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Ramona Pais
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK
| | - Fiona M Gribble
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK.
| | - Frank Reimann
- Institute of Metabolic Sciences and MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, CB0 0QQ, UK.
| |
Collapse
|
40
|
Brubaker PL. Glucagon‐like Peptide‐2 and the Regulation of Intestinal Growth and Function. Compr Physiol 2018; 8:1185-1210. [DOI: 10.1002/cphy.c170055] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
41
|
O'Halloran F, Bruen C, McGrath B, Schellekens H, Murray B, Cryan JF, Kelly AL, McSweeney PL, Giblin L. A casein hydrolysate increases GLP-1 secretion and reduces food intake. Food Chem 2018; 252:303-310. [DOI: 10.1016/j.foodchem.2018.01.107] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 12/13/2017] [Accepted: 01/15/2018] [Indexed: 12/21/2022]
|
42
|
Physiological and therapeutic regulation of glucose homeostasis by upper small intestinal PepT1-mediated protein sensing. Nat Commun 2018; 9:1118. [PMID: 29549253 PMCID: PMC5856761 DOI: 10.1038/s41467-018-03490-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 02/16/2018] [Indexed: 02/07/2023] Open
Abstract
High protein feeding improves glucose homeostasis in rodents and humans with diabetes, but the mechanisms that underlie this improvement remain elusive. Here we show that acute administration of casein hydrolysate directly into the upper small intestine increases glucose tolerance and inhibits glucose production in rats, independently of changes in plasma amino acids, insulin levels, and food intake. Inhibition of upper small intestinal peptide transporter 1 (PepT1), the primary oligopeptide transporter in the small intestine, reverses the preabsorptive ability of upper small intestinal casein infusion to increase glucose tolerance and suppress glucose production. The glucoregulatory role of PepT1 in the upper small intestine of healthy rats is further demonstrated by glucose homeostasis disruption following high protein feeding when PepT1 is inhibited. PepT1-mediated protein-sensing mechanisms also improve glucose homeostasis in models of early-onset insulin resistance and obesity. We demonstrate that preabsorptive upper small intestinal protein-sensing mechanisms mediated by PepT1 have beneficial effects on whole-body glucose homeostasis. High protein diets are known to improve metabolic parameters including adiposity and glucose homeostasis. Here the authors demonstrate that preabsorptive upper small intestinal protein-sensing mechanisms mediated by peptide transporter 1 improve glucose homeostasis by inhibiting hepatic glucose production.
Collapse
|
43
|
Abstract
The gastrointestinal tract represents the largest interface between the human body and the external environment. It must continuously monitor and discriminate between nutrients that need to be assimilated and harmful substances that need to be expelled. The different cells of the gut epithelium are therefore equipped with a subtle chemosensory system that communicates the sensory information to several effector systems involved in the regulation of appetite, immune responses, and gastrointestinal motility. Disturbances or adaptations in the communication of this sensory information may contribute to the development or maintenance of disease. This is a new emerging research field in which perception of taste can be considered as a novel key player participating in the regulation of gut function. Specific diets or agonists that target these chemosensory signaling pathways may be considered as new therapeutic targets to tune adequate physiological processes in the gut in health and disease.
Collapse
Affiliation(s)
- S Steensels
- Translational Research Center for Gastrointestinal Disorders, KU Leuven, 3000 Leuven, Belgium;
| | - I Depoortere
- Translational Research Center for Gastrointestinal Disorders, KU Leuven, 3000 Leuven, Belgium;
| |
Collapse
|
44
|
Gribble FM, Meek CL, Reimann F. Targeted intestinal delivery of incretin secretagogues-towards new diabetes and obesity therapies. Peptides 2018; 100:68-74. [PMID: 29412834 PMCID: PMC5805852 DOI: 10.1016/j.peptides.2017.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 12/11/2022]
Abstract
A new strategy under development for the treatment of type 2 diabetes and obesity is to mimic some of the effects of bariatric surgery by delivering food-related stimuli to the distal gastrointestinal tract where they should enhance the release of gut hormones such as glucagon-like peptide-1 (GLP-1) and peptideYY (PYY). Methods include inhibition of food digestion and absorption in the upper GI tract, or oral delivery of stimuli in capsules or pelleted form to protect them against gastric degradation. A variety of agents have been tested in humans using capsules, microcapsules or pellets, delivering nutrients, bile acids, fatty acids and bitter compounds. This review examines the outcomes of these different approaches and supporting evidence from intestinal perfusion studies.
Collapse
Affiliation(s)
- Fiona M Gribble
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom.
| | - Claire L Meek
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Frank Reimann
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom.
| |
Collapse
|
45
|
Boesmans W, Hao MM, Vanden Berghe P. Optogenetic and chemogenetic techniques for neurogastroenterology. Nat Rev Gastroenterol Hepatol 2018; 15:21-38. [PMID: 29184183 DOI: 10.1038/nrgastro.2017.151] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Optogenetics and chemogenetics comprise a wide variety of applications in which genetically encoded actuators and indicators are used to modulate and monitor activity with high cellular specificity. Over the past 10 years, development of these genetically encoded tools has contributed tremendously to our understanding of integrated physiology. In concert with the continued refinement of probes, strategies to target transgene expression to specific cell types have also made much progress in the past 20 years. In addition, the successful implementation of optogenetic and chemogenetic techniques thrives thanks to ongoing advances in live imaging microscopy and optical technology. Although innovation of optogenetic and chemogenetic methods has been primarily driven by researchers studying the central nervous system, these techniques also hold great promise to boost research in neurogastroenterology. In this Review, we describe the different classes of tools that are currently available and give an overview of the strategies to target them to specific cell types in the gut wall. We discuss the possibilities and limitations of optogenetic and chemogenetic technology in the gut and provide an overview of their current use, with a focus on the enteric nervous system. Furthermore, we suggest some experiments that can advance our understanding of how the intrinsic and extrinsic neural networks of the gut control gastrointestinal function.
Collapse
Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium.,Department of Pathology, Maastricht University Medical Center, P. Debeijelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Marlene M Hao
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium
| |
Collapse
|
46
|
Yang L, Wang L, Zhu C, Wu J, Yuan Y, Yu L, Xu Y, Xu J, Wang T, Liao Z, Wang S, Zhu X, Gao P, Zhang Y, Wang X, Jiang Q, Shu G. Laminarin counteracts diet-induced obesity associated with glucagon-like peptide-1 secretion. Oncotarget 2017; 8:99470-99481. [PMID: 29245916 PMCID: PMC5725107 DOI: 10.18632/oncotarget.19957] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/16/2017] [Indexed: 01/13/2023] Open
Abstract
Laminarin, a type of β-glucan isolated from brown seaweeds, exhibits verity of physiological activities, which include immunology modulation and antitumor function. To investigate the effect of laminarin on energy homeostasis, mice were orally administrated with laminarin to test food intake, fat deposition, and glucose homeostasis. Chronically, laminarin treatment significantly decreases high-fat-diet-induced body weight gain and fat deposition and reduces blood glucose level and glucose tolerance. Acutely, laminarin enhances serum glucagon-like peptide-1 (GLP-1) content and the mRNA expression level of proglucagon and prohormone convertase 1 in ileum. Subsequently, laminarin suppresses the food intake of mice, the hypothalamic AgRP neuron activity, and AgRP expression but activates pancreatic function. Furthermore, laminarin-induced appetite reduction was totally blocked by Exendin (9-39), a specific competitive inhibitor of GLP-1 receptor. Then, STC-1 cells were adopted to address the underlying mechanism, by which laminarin promoted GLP-1 secretion in vitro. Results showed that laminarin dose-dependently promoted GLP-1 secretion and c-Fos protein expression in STC-1 cells, which were independent of Dectin-1 and CD18. Interestingly, BAPTA-AM, a calcium-chelating agent, potently attenuated laminarin-induced [Ca2+]i elevation, c-Fos expression, and GLP-1 secretion. In summary, our data support that laminarin counteracts diet-induced obesity and stimulates GLP-1 secretion via [Ca2+]i; this finding provides an experimental basis for laminarin application to treat obesity and maintain glucose homeostasis.
Collapse
Affiliation(s)
- Liusong Yang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Lina Wang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Canjun Zhu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Junguo Wu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Yexian Yuan
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Lulu Yu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Yaqiong Xu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Jingren Xu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Tao Wang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Zhengrui Liao
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Songbo Wang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| | - Xiaotong Zhu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Ping Gao
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Yongliang Zhang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xiuqi Wang
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| | - Qingyan Jiang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| | - Gang Shu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| |
Collapse
|
47
|
Signalling in the gut endocrine axis. Physiol Behav 2017; 176:183-188. [DOI: 10.1016/j.physbeh.2017.02.039] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 02/06/2023]
|
48
|
Psichas A, Tolhurst G, Brighton CA, Gribble FM, Reimann F. Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells. J Vis Exp 2017. [PMID: 28448057 PMCID: PMC5409300 DOI: 10.3791/55687] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The gut is the largest endocrine organ of the body, with hormone-secreting enteroendocrine cells located along the length of the gastrointestinal epithelium. Despite their physiological importance, enteroendocrine cells represent only a small fraction of the epithelial cell population and in the past, their characterization has presented a considerable challenge resulting in a reliance on cell line models. Here, we provide a detailed protocol for the isolation and culture of mixed murine small intestinal cells. These primary cultures have been used to identify the signaling pathways underlying the stimulation and inhibition of gut peptide secretion in response to a number of nutrients and neuropeptides as well as pharmacological agents. Furthermore, in combination with the use of transgenic fluorescent reporter mice, we have demonstrated that these primary cultures become a powerful tool for the examination of fluorescently-tagged enteroendocrine cells at the intracellular level, using methods such as patch clamping and single-cell calcium and cAMP-FRET imaging.
Collapse
Affiliation(s)
- Arianna Psichas
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge
| | - Gwen Tolhurst
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge
| | - Cheryl A Brighton
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge
| | - Fiona M Gribble
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge;
| | - Frank Reimann
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge;
| |
Collapse
|
49
|
Abstract
In addition to their bioenergetic intracellular function, several classical metabolites act as extracellular signaling molecules activating cell-surface G-protein-coupled receptors (GPCRs), similar to hormones and neurotransmitters. "Signaling metabolites" generated from nutrients or by gut microbiota target primarily enteroendocrine, neuronal, and immune cells in the lamina propria of the gut mucosa and the liver and, through these tissues, the rest of the body. In contrast, metabolites from the intermediary metabolism act mainly as metabolic stress-induced autocrine and paracrine signals in adipose tissue, the liver, and the endocrine pancreas. Importantly, distinct metabolite GPCRs act as efficient pro- and anti-inflammatory regulators of key immune cells, and signaling metabolites may thus function as important drivers of the low-grade inflammation associated with insulin resistance and obesity. The concept of key metabolites as ligands for specific GPCRs has broadened our understanding of metabolic signaling significantly and provides a number of novel potential drug targets.
Collapse
Affiliation(s)
- Anna Sofie Husted
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Mette Trauelsen
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Olga Rudenko
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Siv A Hjorth
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark; Laboratory for Molecular Pharmacology, Department for Biomedical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Thue W Schwartz
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark; Laboratory for Molecular Pharmacology, Department for Biomedical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
| |
Collapse
|
50
|
Fatty acid and mineral receptors as drug targets for gastrointestinal disorders. Future Med Chem 2017; 9:315-334. [DOI: 10.4155/fmc-2016-0205] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nutrient-sensing receptors, including fatty acid receptors (FFA1–FFA4), Ca2+-sensing receptors and Zn2+-sensing receptors, are involved in several biological processes. These receptors are abundantly expressed in the GI tract, where they have been shown to play crucial roles in regulating GI function. This review provides an overview of the GI functions of fatty acid and mineral receptors, including the regulation of gastric and enteroendocrine functions, GI motility, ion transport and cell growth. Recently, several lines of evidence have implicated these receptors as promising therapeutic targets for the treatment of GI disorders, for example, inflammatory bowel disease, colorectal cancer, metabolic syndrome and diarrheal diseases. A future perspective on drug discovery research targeting these receptors is discussed.
Collapse
|