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Mizuta K, Zhang Y, Mizuta F, Hoshijima H, Shiga T, Masaki E, Emala CW. Novel identification of the free fatty acid receptor FFAR1 that promotes contraction in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2015; 309:L970-82. [PMID: 26342087 DOI: 10.1152/ajplung.00041.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 08/31/2015] [Indexed: 02/03/2023] Open
Abstract
Obesity is one of the major risk factors for asthma. Previous studies have demonstrated that free fatty acid levels are elevated in the plasma of obese individuals. Medium- and long-chain free fatty acids act as endogenous ligands for the free fatty acid receptors FFAR1/GPR40 and FFAR4/GPR120, which couple to Gq proteins. We investigated whether FFAR1 and FFAR4 are expressed on airway smooth muscle and whether they activate Gq-coupled signaling and modulate airway smooth muscle tone. We detected the protein expression of FFAR1 and FFAR4 in freshly dissected native human and guinea pig airway smooth muscle and cultured human airway smooth muscle (HASM) cells by immunoblotting and immunohistochemistry. The long-chain free fatty acids (oleic acid and linoleic acid) and GW9508 (FFAR1/FFAR4 dual agonist) dose-dependently stimulated transient intracellular Ca(2+) concentration ([Ca(2+)]i) increases and inositol phosphate synthesis in HASM cells. Downregulation of FFAR1 or FFAR4 in HASM cells by small interfering RNA led to a significant inhibition of the long-chain free fatty acids-induced transient [Ca(2+)]i increases. Oleic acid, linoleic acid, or GW9508 stimulated stress fiber formation in HASM cells, potentiated acetylcholine-contracted guinea pig tracheal rings, and attenuated the relaxant effect of isoproterenol after an acetylcholine-induced contraction. In contrast, TUG-891 (FFAR4 agonist) did not induce the stress fiber formation or potentiate acetylcholine-induced contraction. These results suggest that FFAR1 is the functionally dominant free fatty acid receptor in both human and guinea pig airway smooth muscle. The free fatty acid sensors expressed on airway smooth muscle could be an important modulator of airway smooth muscle tone.
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Affiliation(s)
- Kentaro Mizuta
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; Department of Dento-oral Anesthesiology, Tohoku University Graduate School of Dentistry, Sendai, Japan; and
| | - Yi Zhang
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York
| | - Fumiko Mizuta
- Department of Dento-oral Anesthesiology, Tohoku University Graduate School of Dentistry, Sendai, Japan; and
| | - Hiroshi Hoshijima
- Department of Dento-oral Anesthesiology, Tohoku University Graduate School of Dentistry, Sendai, Japan; and
| | - Toshiya Shiga
- Department of Anesthesiology, Chemotherapy Research Institute, Kaken Hospital, International University of Health and Welfare, Chiba, Japan
| | - Eiji Masaki
- Department of Dento-oral Anesthesiology, Tohoku University Graduate School of Dentistry, Sendai, Japan; and
| | - Charles W Emala
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York
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152
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Christensen LW, Kuhre RE, Janus C, Svendsen B, Holst JJ. Vascular, but not luminal, activation of FFAR1 (GPR40) stimulates GLP-1 secretion from isolated perfused rat small intestine. Physiol Rep 2015; 3:e12551. [PMID: 26381015 PMCID: PMC4600392 DOI: 10.14814/phy2.12551] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/25/2015] [Accepted: 08/29/2015] [Indexed: 12/23/2022] Open
Abstract
Glucagon-like peptide 1 (GLP-1) plays a central role in modern treatment of type 2 diabetes (T2DM) in the form of GLP-1 enhancers and GLP-1 mimetics. An alternative treatment strategy is to stimulate endogenous GLP-1 secretion from enteroendocrine L cells using a targeted approach. The G-protein-coupled receptor, FFAR1 (previously GPR40), expressed on L cells and activated by long-chain fatty acids (LCFAs) is a potential target. A link between FFAR1 activation and GLP-1 secretion has been demonstrated in cellular models and small-molecule FFAR1 agonists have been developed. In this study, we examined the effect of FFAR1 activation on GLP-1 secretion using isolated, perfused small intestines from rats, a physiologically relevant model allowing distinction between direct and indirect effects of FFAR1 activation. The endogenous FFAR1 ligand, linoleic acid (LA), and four synthetic FFAR1 agonists (TAK-875, AMG 837, AM-1638, and AM-5262) were administered through intraluminal and intra-arterial routes, respectively, and dynamic changes in GLP-1 secretion were evaluated. Vascular administration of 10 μmol/L TAK-875, 10 μmol/L AMG 837, 1 μmol/L and 0.1 μmol/L AM-1638, 1 μmol/L AM-6252, and 1 mmol/L LA, all significantly increased GLP-1 secretion compared to basal levels (P < 0.05), whereas luminal administration of LA and FFAR1 agonists was ineffective. Thus, both natural and small-molecule agonists of the FFAR1 receptor appear to require absorption prior to stimulating GLP-1 secretion, indicating that therapies based on activation of nutrient sensing may be more complex than hitherto expected.
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Affiliation(s)
- Louise W Christensen
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute University of Copenhagen, Copenhagen, Denmark
| | - Rune E Kuhre
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Janus
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute University of Copenhagen, Copenhagen, Denmark
| | - Berit Svendsen
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute University of Copenhagen, Copenhagen, Denmark
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153
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FFA4 receptor (GPR120): A hot target for the development of anti-diabetic therapies. Eur J Pharmacol 2015; 763:160-8. [DOI: 10.1016/j.ejphar.2015.06.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/14/2015] [Accepted: 06/15/2015] [Indexed: 12/12/2022]
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154
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Ciullo DL, Dotson CD. Using Animal Models to Determine the Role of Gustatory Neural Input in the Control of Ingestive Behavior and the Maintenance of Body Weight. CHEMOSENS PERCEPT 2015; 8:61-77. [PMID: 26557212 PMCID: PMC4636125 DOI: 10.1007/s12078-015-9190-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Decades of research have suggested that nutritional intake contributes to the development of human disease, mainly by influencing the development of obesity and obesity-related conditions. A relatively large body of research indicates that functional variation in human taste perception can influence nutritional intake as well as body mass accumulation. However, there are a considerable number of studies that suggest that no link between these variables actually exists. These discrepancies in the literature likely result from the confounding influence of a variety of other, uncontrolled, factors that can influence ingestive behavior. STRATEGY In this review, the use of controlled animal experimentation to alleviate at least some of these issues related to the lack of control of experimental variables is discussed. Specific examples of the use of some of these techniques are examined. DISCUSSION AND CONCLUSIONS The review will close with some specific suggestions aimed at strengthening the link between gustatory neural input and its putative influence on ingestive behaviors and the maintenance of body weight.
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Affiliation(s)
- Dana L Ciullo
- Departments of Neuroscience and Psychiatry, Division of Addiction Medicine, University of Florida College of Medicine, and Center for Smell and Taste, University of Florida, Gainesville, FL 32611, USA,
| | - Cedrick D Dotson
- Departments of Neuroscience and Psychiatry, Division of Addiction Medicine, University of Florida College of Medicine, and Center for Smell and Taste, University of Florida, Gainesville, FL 32611, USA,
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155
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Biological characteristics and agonists of GPR120 (FFAR4) receptor: the present status of research. Future Med Chem 2015; 7:1457-68. [DOI: 10.4155/fmc.15.75] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
GPR120 receptor functions as a receptor for ω-3 fatty acid, involving regulating the secretion of gastrointestinal peptide hormone, adipogenesis, adipogenic differentiation and anti-inflammatory process and the like in the aspect of biological functions. In view that the dysfunction of GPR120 receptor is closely correlated with metabolic disorders, GPR120 may act as a novel potential therapeutic target for the treatment of obesity, insulin resistance, Type 2 diabetes and so on. Therefore, mounting scientists devote themselves to probing the molecular mechanism of the biological function of GPR120 receptor and their ligands for the treatment of impaired metabolic health. Herein, we summarize the mechanisms of signal transduction through GPR120 receptor, and discovery and development of GPR120 agonists thereof.
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156
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Mancini AD, Poitout V. GPR40 agonists for the treatment of type 2 diabetes: life after 'TAKing' a hit. Diabetes Obes Metab 2015; 17:622-9. [PMID: 25604916 DOI: 10.1111/dom.12442] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/13/2015] [Accepted: 01/17/2015] [Indexed: 12/17/2022]
Abstract
The free fatty acid receptor GPR40 has been proposed as a potential target for type 2 diabetes (T2D) pharmacotherapy. This idea has been validated in both preclinical and clinical studies, in which activation of GPR40 was shown to improve glycaemic control by stimulating glucose-dependent insulin secretion; however, the recent termination of phase III clinical trials using the GPR40 agonist TAK-875 (fasiglifam) has raised important questions regarding the long-term safety and viability of targeting GPR40 and, more specifically, about our understanding of this receptor's basic biology. In the present review, we provide a summary of established and novel concepts related to GPR40's pharmacobiology and discuss the current status and future outlook for GPR40-based drug development for the treatment of T2D.
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Affiliation(s)
- A D Mancini
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
- Department of Medicine, Université de Montréal, Montréal, QC, Canada
| | - V Poitout
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
- Department of Medicine, Université de Montréal, Montréal, QC, Canada
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157
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Cardiac gene expression data and in silico analysis provide novel insights into human and mouse taste receptor gene regulation. Naunyn Schmiedebergs Arch Pharmacol 2015; 388:1009-27. [PMID: 25986534 DOI: 10.1007/s00210-015-1118-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/24/2015] [Indexed: 12/21/2022]
Abstract
G protein-coupled receptors are the principal mediators of the sweet, umami, bitter, and fat taste qualities in mammals. Intriguingly, the taste receptors are also expressed outside of the oral cavity, including in the gut, airways, brain, and heart, where they have additional functions and contribute to disease. However, there is little known about the mechanisms governing the transcriptional regulation of taste receptor genes. Following our recent delineation of taste receptors in the heart, we investigated the genomic loci encoding for taste receptors to gain insight into the regulatory mechanisms that drive their expression in the heart. Gene expression analyses of healthy and diseased human and mouse hearts showed coordinated expression for a subset of chromosomally clustered taste receptors. This chromosomal clustering mirrored the cardiac expression profile, suggesting that a common gene regulatory block may control the taste receptor locus. We identified unique domains with strong regulatory potential in the vicinity of taste receptor genes. We also performed de novo motif enrichment in the proximal promoter regions and found several overrepresented DNA motifs in cardiac taste receptor gene promoters corresponding to ubiquitous and cardiac-specific transcription factor binding sites. Thus, combining cardiac gene expression data with bioinformatic analyses, this study has provided insights into the noncoding regulatory landscape for taste GPCRs. These findings also have broader relevance for the study of taste GPCRs outside of the classical gustatory system, where understanding the mechanisms controlling the expression of these receptors may have implications for future therapeutic development.
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158
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Cloning and characterization of spliced variants of the porcine G protein coupled receptor 120. BIOMED RESEARCH INTERNATIONAL 2015; 2015:813816. [PMID: 26075265 PMCID: PMC4449883 DOI: 10.1155/2015/813816] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/02/2015] [Accepted: 05/02/2015] [Indexed: 11/17/2022]
Abstract
The polyunsaturated fatty acids (PUFAs) receptor GPR120 exerts a significant impact on systemic nutrient homeostasis in human and rodents. However, the porcine GPR120 (pGPR120) has not been well characterized. In the current study, we found that pGPR120 had 3 spliced variants. Transcript 1 encoded 362-amino acids (aa) wild type pGPR120-WT, which shared 88% homology with human short form GPR120. Transcript 1 was the mainly expressed transcript of pGPR120. It was expressed predominantly in ileum, jejunum, duodenum, spleen, and adipose. Transcript 3 (coding 320-aa isoform) was detected in spleen, while the transcript 2 (coding 310-aa isoform) was only slightly expressed in spleen. A selective agonist for human GPR120 (TUG-891) and PUFAs activated SRE-luc and NFAT-luc reporter in HEK293T cells transfected with construct for pGPR120-WT but not pGPR120-V2. However, 320-aa isoform was not a dominant negative isoform. The extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation levels in cells transfected with construct for pGPR120-WT were well activated by PUFAs, especially n-3 PUFA. These results showed that although pGPR120 had 3 transcripts, transcript 1 which encoded pGPR120-WT was the mainly expressed transcript. TUG-891 and PUFAs, especially n-3 PUFA, well activated pGPR120-WT. The current study contributed to dissecting the molecular regulation mechanisms of n-3 PUFA in pigs.
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159
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Camilleri M. Peripheral mechanisms in appetite regulation. Gastroenterology 2015; 148:1219-33. [PMID: 25241326 PMCID: PMC4369188 DOI: 10.1053/j.gastro.2014.09.016] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/09/2014] [Accepted: 09/15/2014] [Indexed: 12/13/2022]
Abstract
Peripheral mechanisms in appetite regulation include the motor functions of the stomach, such as the rate of emptying and accommodation, which convey symptoms of satiation to the brain. The rich repertoire of peripherally released peptides and hormones provides feedback from the arrival of nutrients in different regions of the gut from where they are released to exert effects on satiation, or regulate metabolism through their incretin effects. Ultimately, these peripheral factors provide input to the highly organized hypothalamic circuitry and vagal complex of nuclei to determine cessation of energy intake during meal ingestion, and the return of appetite and hunger after fasting. Understanding these mechanisms is key to the physiological control of feeding and the derangements that occur in obesity and their restoration with treatment (as shown by the effects of bariatric surgery).
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Mayo Clinic College of Medicine, Rochester, Minnesota.
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160
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Cvijanovic N, Feinle-Bisset C, Young RL, Little TJ. Oral and intestinal sweet and fat tasting: impact of receptor polymorphisms and dietary modulation for metabolic disease. Nutr Rev 2015; 73:318-334. [DOI: 10.1093/nutrit/nuu026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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161
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Sclafani A, Touzani K, Ackroff K. Intragastric fat self-administration is impaired in GPR40/120 double knockout mice. Physiol Behav 2015; 147:141-8. [PMID: 25911263 DOI: 10.1016/j.physbeh.2015.04.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/18/2015] [Accepted: 04/14/2015] [Indexed: 11/15/2022]
Abstract
Mice acquire strong preferences for flavors paired with intragastric (IG) fat infusions. This IG fat conditioning is attenuated in double knockout (DoKO) mice missing GPR40 and GPR120 fatty acid receptors. Here we determined if GPR40/120 DoKO mice are also impaired in IG fat self-administration in an operant lick task. In daily 1-h sessions the mice were trained with a sipper spout that contained dry food pellets; licks on the spout triggered infusions of IG fat (Intralipid). The training sessions were followed by test sessions with an empty spout. GPR40/120 DoKO mice self-infused more 20% fat than wild type (WT) C57BL/6 mice in training with a food-baited spout (2.4 vs. 2.0kcal/h) but self-infused less 20% fat than WT mice in empty spout tests (1.2 vs. 1.7kcal/h). The DoKO mice also self-infused less 5% fat than WT mice (0.6 vs. 1.3kcal/h) although both groups emitted more licks for 5% fat than 20% fat. The DoKO and WT mice did not differ, however, in their self-infusion of 12.5% glucose (1.5 vs. 1.6kcal/h), which is isocaloric to 5% fat. A second 5% IL test showed that the DoKO mice reverted to a reduced self-infusion compared to WT mice. When the infusion was shifted to water, WT mice reduced licking in the first extinction session, whereas DoKO mice were less sensitive to the absence of infused fat. Our results indicate that post-oral GPR40/120 signaling is not required to process IG fat infusions in food-baited spout training sessions but contributes to post-oral fat reinforcement in empty spout tests and flavor conditioning tests.
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162
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Abstract
Levels of obesity have reached epidemic proportions on a global scale, which has led to considerable increases in health problems and increased risk of several diseases, including cardiovascular and pulmonary diseases, cancer and diabetes mellitus. People with obesity consume more food than is needed to maintain an ideal body weight, despite the discrimination that accompanies being overweight and the wealth of available information that overconsumption is detrimental to health. The relationship between energy expenditure and energy intake throughout an individual's lifetime is far more complicated than previously thought. An improved comprehension of the relationships between taste, palatability, taste receptors and hedonic responses to food might lead to increased understanding of the biological underpinnings of energy acquisition, as well as why humans sometimes eat more than is needed and more than we know is healthy. This Review discusses the role of taste receptors in the tongue, gut, pancreas and brain and their hormonal involvement in taste perception, as well as the relationship between taste perception, overeating and the development of obesity.
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Affiliation(s)
- Sara Santa-Cruz Calvo
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Biomedical Research Center, Room 09B133, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA
| | - Josephine M Egan
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Biomedical Research Center, Room 09B133, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA
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163
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The A allele of cluster of differentiation 36 (CD36) SNP 1761667 associates with decreased lipid taste perception in obese Tunisian women. Br J Nutr 2015; 113:1330-7. [PMID: 25822988 DOI: 10.1017/s0007114515000343] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent studies have suggested that excessive intake of dietary fat is associated with obesity. Some obese subjects have been reported to exhibit high thresholds for the gustatory detection of lipids via lipid receptors, such as cluster of differentiation 36 (CD36). We studied lingual detection thresholds for emulsions containing oleic acid in obese Tunisian women (n 203) using a three-alternative forced choice (3-AFC) method. Genotyping of the TNF-α (rs1800629), IL-6 (rs1800795) and CD36 (rs1761667) genes was performed to associate with lipid taste perception thresholds. The CD36 genotype distribution was as follows: GG (n 42), AG (n 102) and AA (n 59). Women with the CD36 GG genotype exhibited oral detection thresholds for oleic acid that were more than three times lower than those with the CD36 AA genotype. The present study confirms a high threshold of gustatory fat detection in obese women with the CD36 AA genotype, but there is no significant association with the IL-6 and TNF-α gene polymorphisms.
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164
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Wauquier F, Léotoing L, Philippe C, Spilmont M, Coxam V, Wittrant Y. Pros and cons of fatty acids in bone biology. Prog Lipid Res 2015; 58:121-45. [PMID: 25835096 DOI: 10.1016/j.plipres.2015.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/06/2015] [Accepted: 03/23/2015] [Indexed: 12/12/2022]
Abstract
Despite the growing interest in deciphering the causes and consequences of obesity-related disorders, the mechanisms linking fat intake to bone behaviour remain unclear. Since bone fractures are widely associated with increased morbidity and mortality, most notably in elderly and obese people, bone health has become a major social and economic issue. Consistently, public health system guidelines have encouraged low-fat diets in order to reduce associated complications. However, from a bone point of view, mechanisms linking fat intake to bone alteration remain quite controversial. Thus, after more than a decade of dedicated studies, this timely review offers a comprehensive overview of the relationships between bone and fatty acids. Using clinical evidences as a starting-point to more complex molecular elucidation, this work highlights the complexity of the system and reveals that bone alteration that cannot be solved simply by taking ω-3 pills. Fatty acid effects on bone metabolism can be both direct and indirect and require integrated investigations. Furthermore, even at the level of a single cell, one fatty acid is able to trigger several different independent pathways (receptors, metabolites…) which may all have a say in the final cellular metabolic response.
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Affiliation(s)
- Fabien Wauquier
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Laurent Léotoing
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Claire Philippe
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Mélanie Spilmont
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Véronique Coxam
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Yohann Wittrant
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France.
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165
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Melis M, Sollai G, Muroni P, Crnjar R, Barbarossa IT. Associations between orosensory perception of oleic acid, the common single nucleotide polymorphisms (rs1761667 and rs1527483) in the CD36 gene, and 6-n-propylthiouracil (PROP) tasting. Nutrients 2015; 7:2068-84. [PMID: 25803547 PMCID: PMC4377901 DOI: 10.3390/nu7032068] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/02/2015] [Accepted: 03/12/2015] [Indexed: 12/16/2022] Open
Abstract
Orosensory perception of dietary fat varies in individuals, thus influencing nutritional status. Several studies associated fat detection and preference with CD36 or 6-n-propylthiouracil (PROP) sensitivity. Other studies have not confirmed the latter association. We analyzed the relationship between orosensory perception of oleic acid, two CD36 variants, and PROP tasting. Thresholds of oleic acid perception were assessed in 64 subjects using a modification of the three-alternative forced-choice procedure. Subjects were classified for PROP taster status and genotyped for TAS2R38 and CD36 (SNPs: rs1761667 and rs1527483). Subjects homozygous for GG of the rs1761667 polymorphism showed higher sensitivity to oleic acid than AA subjects. The capability to detect oleic acid was directly associated with TAS2R38 or PROP responsiveness. PROP non-tasters had a lower papilla density than tasters, and those with genotype GG of the rs1761667 polymorphism had lower oleic acid thresholds than PROP non-tasters with genotype AA. In conclusion, results showed a direct association between orosensory perception of oleic acid and PROP tasting or rs1761667 polymorphism of CD36, which play a significant role in PROP non-tasters, given their low number of taste papillae. Characterization of individual capability to detect fatty acids may have important nutritional implications by explaining variations in human fat preferences.
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Affiliation(s)
- Melania Melis
- Department of Biomedical Sciences, University of Cagliari, Monserrato, CA 09042, Italy.
| | - Giorgia Sollai
- Department of Biomedical Sciences, University of Cagliari, Monserrato, CA 09042, Italy.
| | - Patrizia Muroni
- Department of Biomedical Sciences, University of Cagliari, Monserrato, CA 09042, Italy.
| | - Roberto Crnjar
- Department of Biomedical Sciences, University of Cagliari, Monserrato, CA 09042, Italy.
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166
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Konno Y, Ueki S, Takeda M, Kobayashi Y, Tamaki M, Moritoki Y, Oyamada H, Itoga M, Kayaba H, Omokawa A, Hirokawa M. Functional analysis of free fatty acid receptor GPR120 in human eosinophils: implications in metabolic homeostasis. PLoS One 2015; 10:e0120386. [PMID: 25790291 PMCID: PMC4366258 DOI: 10.1371/journal.pone.0120386] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/21/2015] [Indexed: 01/21/2023] Open
Abstract
Recent evidence has shown that eosinophils play an important role in metabolic homeostasis through Th2 cytokine production. GPR120 (FFA4) is a G protein-coupled receptor (GPCR) for long-chain fatty acids that functions as a regulator of physiological energy metabolism. In the present study, we aimed to investigate whether human eosinophils express GPR120 and, if present, whether it possesses a functional capacity on eosinophils. Eosinophils isolated from peripheral venous blood expressed GPR120 at both the mRNA and protein levels. Stimulation with a synthetic GPR120 agonist, GW9508, induced rapid down-regulation of cell surface expression of GPR120, suggesting ligand-dependent receptor internalization. Although GPR120 activation did not induce eosinophil chemotactic response and degranulation, we found that GW9508 inhibited eosinophil spontaneous apoptosis and Fas receptor expression. The anti-apoptotic effect was attenuated by phosphoinositide 3-kinase (PI3K) inhibitors and was associated with inhibition of caspase-3 activity. Eosinophil response investigated using ELISpot assay indicated that stimulation with a GPR120 agonist induced IL-4 secretion. These findings demonstrate the novel functional properties of fatty acid sensor GPR120 on human eosinophils and indicate the previously unrecognized link between nutrient metabolism and the immune system.
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Affiliation(s)
- Yasunori Konno
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Shigeharu Ueki
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
- * E-mail:
| | - Masahide Takeda
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Yoshiki Kobayashi
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
- Department of Otolaryngology, Kansai Medical University, Shin-machi, Hirakata City, Osaka, Japan
| | - Mami Tamaki
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Yuki Moritoki
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Hajime Oyamada
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Masamichi Itoga
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
- Department of Clinical Laboratory Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hiroyuki Kayaba
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
- Department of Clinical Laboratory Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ayumi Omokawa
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Makoto Hirokawa
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
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167
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Abstract
Fat is a vital macronutrient, and its intake is closely monitored by an array of molecular sensors distributed throughout the alimentary canal. In the mouth, dietary fat constituents such as mono- and diunsaturated fatty acids give rise to taste signals that stimulate food intake, in part by enhancing the production of lipid-derived endocannabinoid messengers in the gut. As fat-containing chyme enters the small intestine, it causes the formation of anorexic lipid mediators, such as oleoylethanolamide, which promote satiety. These anatomically and functionally distinct responses may contribute to the homeostatic control and, possibly, the pathological dysregulation of food intake.
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Affiliation(s)
| | - Daniele Piomelli
- Departments of Anatomy and Neurobiology
- Department of Pharmacology, and
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California, USA
- Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
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168
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Sawamura R, Kawabata Y, Kawabata F, Nishimura S, Tabata S. The role of G-protein-coupled receptor 120 in fatty acids sensing in chicken oral tissues. Biochem Biophys Res Commun 2015; 458:387-91. [DOI: 10.1016/j.bbrc.2015.01.125] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 01/25/2015] [Indexed: 10/24/2022]
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169
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Running CA, Mattes RD. Humans are more sensitive to the taste of linoleic and α-linolenic than oleic acid. Am J Physiol Gastrointest Liver Physiol 2015; 308:G442-9. [PMID: 25540234 DOI: 10.1152/ajpgi.00394.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Health concerns have led to recommendations to replace saturated fats with unsaturated fats. However, addition of unsaturated fatty acids may lead to changes in the way foods are perceived in the oral cavity. This study tested the taste sensitivity to and emulsion characteristics of oleic, linoleic, and α-linolenic acids. The hypothesis tested was that oral sensitivity to nonesterified fatty acids would increase with degree of unsaturation but that in vitro viscosities and particle sizes of these emulsions would not differ. Oral taste thresholds were obtained using the three-alternative, forced-choice, ascending method. Each participant was tested on each fat 7 times, for a total of 21 study visits, to account for learning effects. Viscosities were obtained for the blank solutions and all three emulsions. Results indicate lower oral thresholds to linoleic and α-linolenic than oleic acid. At higher shear rates, 5% oleic and linoleic acid were more viscous than other samples. More-dilute emulsions showed no significant differences in viscosity. Particle sizes of the emulsions increased very slightly with increasing unsaturation. Together, the emulsion characteristics and oral sensitivity data support a taste mechanism for nonesterified fatty acid detection.
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Affiliation(s)
- Cordelia A Running
- Department of Food Science, Purdue University, West Lafayette, Indiana; and
| | - Richard D Mattes
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
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170
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Widmayer P, Goldschmid H, Henkel H, Küper M, Königsrainer A, Breer H. High fat feeding affects the number of GPR120 cells and enteroendocrine cells in the mouse stomach. Front Physiol 2015; 6:53. [PMID: 25774135 PMCID: PMC4343009 DOI: 10.3389/fphys.2015.00053] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 02/05/2015] [Indexed: 01/24/2023] Open
Abstract
Long-term intake of dietary fat is supposed to be associated with adaptive reactions of the organism and it is assumptive that this is particularly true for fat responsive epithelial cells in the mucosa of the gastrointestinal tract. Recent studies suggest that epithelial cells expressing the receptor for medium and long chain fatty acids, GPR120 (FFAR4), may operate as fat sensors. Changes in expression level and/or cell density are supposed to be accompanied with a consumption of high fat (HF) diet. To assess whether feeding a HF diet might impact on the expression of fatty acid receptors or the number of lipid sensing cells as well as enteroendocrine cell populations, gastric tissue samples of non-obese and obese mice were compared using a real time PCR and immunohistochemical approach. In this study, we have identified GPR120 cells in the corpus region of the mouse stomach which appeared to be brush cells. Monitoring the effect of HF diet on the expression of GPR120 revealed that after 3 weeks and 6 months the level of mRNA for GPR120 in the tissue was significantly increased which coincided with and probably reflected a significant increase in the number of GPR120 positive cells in the corpus region; in contrast, within the antrum region, the number of GPR120 cells decreased. Furthermore, dietary fat intake also led to changes in the number of enteroendocrine cells producing either ghrelin or gastrin. After 3 weeks and even more pronounced after 6 months the number of ghrelin cells and gastrin cells was significantly increased. These results imply that a HF diet leads to significant changes in the cellular repertoire of the stomach mucosa. Whether these changes are a consequence of the direct exposure to HF in the luminal content or a physiological response to the high level of fat in the body remains elusive.
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Affiliation(s)
| | | | - Helena Henkel
- Institute of Physiology, University of Hohenheim Stuttgart, Germany
| | - Markus Küper
- Visceral and Transplant Surgery, University Hospital for General Tübingen, Germany
| | - Alfred Königsrainer
- Visceral and Transplant Surgery, University Hospital for General Tübingen, Germany
| | - Heinz Breer
- Institute of Physiology, University of Hohenheim Stuttgart, Germany
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171
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172
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Sayed A, Šerý O, Plesnik J, Daoudi H, Rouabah A, Rouabah L, Khan NA. CD36 AA genotype is associated with decreased lipid taste perception in young obese, but not lean, children. Int J Obes (Lond) 2015; 39:920-4. [PMID: 25687220 DOI: 10.1038/ijo.2015.20] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 10/23/2014] [Accepted: 11/02/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND/OBJECTIVE Obesity is an alarming threat for all age groups, including children. Fat overconsumption is one of the factors that directly influences this pathology. Recent studies have suggested that a common variant in the CD36 gene, that is, single-nucleotide polymorphism (SNP) rs1761667-A allele, that reduces CD36 expression, associates with high oral fat detection thresholds in some obese subjects. The objective was to assess fatty acid sensitivity in relation to CD36 SNP in young lean and obese children. SUBJECTS/METHODS We studied lingual detection thresholds for emulsions, containing oleic acid, in Algerian children (n=116, age=8±0.5 years) who were divided into two groups: obese (n=57; body mass index (BMI) z-score=2.513±0.490) and lean children (n=59; BMI z-score=-0.138±0.601) by alternative-forced choice method. To correlate the lipid taste perception thresholds with CD36 SNP, the children were genotyped for A/G SNP rs1761667 in 5'UTR region of CD36 by using PCR and restriction fragment length polymorphism. RESULTS We noticed significantly higher CD36 A-allele frequency (P=0.036) in young obese children compared with leans. CD36 A-allele was associated with higher lipid taste perception thresholds than G-allele in obese children, but not in lean controls. Moreover, waist circumference was positively correlated with reduced fat taste sensitivity in these children. CONCLUSIONS CD36 SNP A-allele, being present both in young lean and in obese children, is associated with high threshold for fatty acid taste sensitivity only in obese children.
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Affiliation(s)
- A Sayed
- Laborartoire de Biologie Cellulaire and Moléculaire, Université de Constantine 1, Constantine, Algérie
| | - O Šerý
- 1] Institute of Animal Physiology and Genetics, Academy of Science, Brno, Czech Republic [2] Laboratory of Neurobiology and Molecular Psychiatry, Laboratory of Molecular Physiology, Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - J Plesnik
- 1] Laboratory of Neurobiology and Molecular Psychiatry, Laboratory of Molecular Physiology, Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic [2] Physiologie de la Nutrition and Toxicologie, UMR U866 INSERM/Université de Bourgogne/Agro-Sup, Dijon, France
| | - H Daoudi
- Laborartoire de Biologie Cellulaire and Moléculaire, Université de Constantine 1, Constantine, Algérie
| | - A Rouabah
- Laborartoire de Biologie Cellulaire and Moléculaire, Université de Constantine 1, Constantine, Algérie
| | - L Rouabah
- Laborartoire de Biologie Cellulaire and Moléculaire, Université de Constantine 1, Constantine, Algérie
| | - N A Khan
- Physiologie de la Nutrition and Toxicologie, UMR U866 INSERM/Université de Bourgogne/Agro-Sup, Dijon, France
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173
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Overexpression of G-protein-coupled receptor 40 enhances the mitogenic response to epoxyeicosatrienoic acids. PLoS One 2015; 10:e0113130. [PMID: 25679385 PMCID: PMC4332471 DOI: 10.1371/journal.pone.0113130] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/20/2014] [Indexed: 11/19/2022] Open
Abstract
The cytochrome P450 epoxygenase-dependent arachidonic acid metabolites, epoxyeicosatrienoic acids (EETs), are potent survival factors and mitogens for renal epithelial cells, but the molecular identity in the cells that initiates the mitogenic signaling of EETs has remained elusive. We screened kidney cell lines for the expression of G-protein-coupled receptor 40 (GPR40) and found that the porcine renal tubular epithelial cell line LLCPKcl4, which has been previously demonstrated to be sensitive to the mitogenic effect of EETs, expresses higher levels of GPR40 mRNA and protein than the human embryonic kidney cell line HEK293. EETs induced only a weak mitogenic EGFR signaling and mild cell proliferation in HEK293 cells. To determine whether GPR40 expression level is what mediates the mitogenic sensitivity of cells to EETs, we created a human GPR40 (hGPR40) cDNA construct and transfected it into HEK293 cells and picked up a number of stable transfectants. We found that GPR40 overexpression in HEK293 cells indeed significantly enhanced EET-induced cell proliferation and markedly augmented EGFR phosphorylation ERK activation, which were inhibited by the EGFR tyrosine kinase inhibitor, AG1478, or the HB-EGF inhibitor, CRM197. EETs significantly enhanced release of soluble HB-EGF, a natural ligand of EGFR, into the culture medium of hGPR40-transfected HEK293 cells, compared to empty vector-transfected cells. In mouse kidneys, markedly higher level of GPR40 protein was found in the cortex and outer stripe of outer medulla compared to the inner stripe of outer medulla and inner medulla. In situ hybridization confirmed that GPR40 mRNA was localized to a subset of renal tubules in the kidney, including the cortical collecting duct. Thus, this study provides the first demonstration that upregulation of GPR40 expression enhances the mitogenic response to EETs and a relatively high expression level of GPR40 is detected in a subset of tubules including cortical collecting ducts in the mammalian kidney.
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174
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Keast RSJ, Costanzo A. Is fat the sixth taste primary? Evidence and implications. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/2044-7248-4-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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175
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Nutrient-sensing mechanisms and pathways. Nature 2015; 517:302-10. [PMID: 25592535 DOI: 10.1038/nature14190] [Citation(s) in RCA: 744] [Impact Index Per Article: 82.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/02/2014] [Indexed: 12/14/2022]
Abstract
The ability to sense and respond to fluctuations in environmental nutrient levels is a requisite for life. Nutrient scarcity is a selective pressure that has shaped the evolution of most cellular processes. Different pathways that detect intracellular and extracellular levels of sugars, amino acids, lipids and surrogate metabolites are integrated and coordinated at the organismal level through hormonal signals. During food abundance, nutrient-sensing pathways engage anabolism and storage, whereas scarcity triggers homeostatic mechanisms, such as the mobilization of internal stores through autophagy. Nutrient-sensing pathways are commonly deregulated in human metabolic diseases.
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176
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Bhatla N, Horvitz HR. Light and hydrogen peroxide inhibit C. elegans Feeding through gustatory receptor orthologs and pharyngeal neurons. Neuron 2015; 85:804-18. [PMID: 25640076 DOI: 10.1016/j.neuron.2014.12.061] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 11/11/2014] [Accepted: 12/22/2014] [Indexed: 11/29/2022]
Abstract
While gustatory sensing of the five primary flavors (sweet, salty, sour, bitter, and savory) has been extensively studied, pathways that detect non-canonical taste stimuli remain relatively unexplored. In particular, while reactive oxygen species cause generalized damage to biological systems, no gustatory mechanism to prevent ingestion of such material has been identified in any organism. We observed that light inhibits C. elegans feeding and used light as a tool to uncover molecular and neural mechanisms for gustation. Light can generate hydrogen peroxide, and we discovered that hydrogen peroxide similarly inhibits feeding. The gustatory receptor family members LITE-1 and GUR-3 are required for the inhibition of feeding by light and hydrogen peroxide. The I2 pharyngeal neurons increase calcium in response to light and hydrogen peroxide, and these responses require GUR-3 and a conserved antioxidant enzyme peroxiredoxin PRDX-2. Our results demonstrate a gustatory mechanism that mediates the detection and blocks ingestion of a non-canonical taste stimulus, hydrogen peroxide.
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Affiliation(s)
- Nikhil Bhatla
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - H Robert Horvitz
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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177
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Sakamoto K, Matsumura S, Okafuji Y, Eguchi A, Yoneda T, Mizushige T, Tsuzuki S, Inoue K, Fushiki T. The opioid system contributes to the acquisition of reinforcement for dietary fat but is not required for its maintenance. Physiol Behav 2015; 138:227-35. [DOI: 10.1016/j.physbeh.2014.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/31/2014] [Accepted: 11/02/2014] [Indexed: 10/24/2022]
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178
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Lee RJ, Cohen NA. Taste receptors in innate immunity. Cell Mol Life Sci 2015; 72:217-36. [PMID: 25323130 PMCID: PMC4286424 DOI: 10.1007/s00018-014-1736-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/11/2014] [Accepted: 09/16/2014] [Indexed: 02/07/2023]
Abstract
Taste receptors were first identified on the tongue, where they initiate a signaling pathway that communicates information to the brain about the nutrient content or potential toxicity of ingested foods. However, recent research has shown that taste receptors are also expressed in a myriad of other tissues, from the airway and gastrointestinal epithelia to the pancreas and brain. The functions of many of these extraoral taste receptors remain unknown, but emerging evidence suggests that bitter and sweet taste receptors in the airway are important sentinels of innate immunity. This review discusses taste receptor signaling, focusing on the G-protein-coupled receptors that detect bitter, sweet, and savory tastes, followed by an overview of extraoral taste receptors and in-depth discussion of studies demonstrating the roles of taste receptors in airway innate immunity. Future research on extraoral taste receptors has significant potential for identification of novel immune mechanisms and insights into host-pathogen interactions.
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Affiliation(s)
- Robert J. Lee
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5th floor, Philadelphia, PA 19104 USA
| | - Noam A. Cohen
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5th floor, Philadelphia, PA 19104 USA
- Philadelphia Veterans Affairs Medical Center Surgical Services, 3900 Woodland Ave, Philadelphia, PA 19104 USA
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179
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Doty RL. Neurotoxic exposure and impairment of the chemical senses of taste and smell. HANDBOOK OF CLINICAL NEUROLOGY 2015; 131:299-324. [PMID: 26563795 DOI: 10.1016/b978-0-444-62627-1.00016-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The chemical senses of taste and smell determine the flavor of foods and beverages, guide appropriate food intake, and warn of such environmental hazards as spoiled or poisonous food, leaking natural gas, smoke, and airborne pollutants. This chapter addresses the influences of neurotoxic exposures on human chemoreception and provides basic information on the adverse influences of such exposures on rodent epithelia. The focus of the chapter is in olfaction, given dearth of empiric research on the effects of neurotoxic chemical exposures on the sense of taste, i.e., sweet, sour, bitter, salty, and savory sensations. As will be apparent from the chapter, numerous neurotoxins--many of which are encountered in industrial workplaces--alter the ability to smell, including solvents, metals, and particulate matter. The olfactory system is particularly vulnerable to such agents since its receptors are more or less directly exposed to the outside environment. Importantly, some such agents can enter the brain via the olfactory nerve or surrounding perineural spaces, bypassing the blood-brain barrier and damaging central nervous system structures and inducing pathologic processes that appear to be similar to those seen in neurodegenerative diseases such as Alzheimer's and Parkinson's.
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Affiliation(s)
- Richard L Doty
- Smell and Taste Center, Department of Otorhinolaryngology; Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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180
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Sakamoto K, Okahashi T, Matsumura S, Okafuji Y, Adachi SI, Tsuzuki S, Inoue K, Fushiki T. The opioid system majorly contributes to preference for fat emulsions but not sucrose solutions in mice. Biosci Biotechnol Biochem 2014; 79:658-63. [PMID: 25516200 DOI: 10.1080/09168451.2014.991688] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Rodents show a stronger preference for fat than sucrose, even if their diet is isocaloric. This implies that the preference mechanisms for fat and sucrose differ. To compare the contribution of the opioid system to the preference of fat and sucrose, we examined the effects of mu-, delta-, kappa-, and non-selective opioid receptor antagonists on the preference of sucrose and fat, assessed by a two-bottle choice test and a licking test, in mice naïve to sucrose and fat ingestion. Administration of non-selective and mu-selective opioid receptor antagonists more strongly inhibited the preference of fat than sucrose. While the preference of fat was reduced to the same level as water by the antagonist administration that of sucrose was still greater than water. Our results suggest that the preference of fat relies strongly on the opioid system, while that of sucrose is regulated by other mechanisms in addition to the opioid system.
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Affiliation(s)
- Kazuhiro Sakamoto
- a Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture , Kyoto University , Kyoto , Japan
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181
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Ancel D, Bernard A, Subramaniam S, Hirasawa A, Tsujimoto G, Hashimoto T, Passilly-Degrace P, Khan NA, Besnard P. The oral lipid sensor GPR120 is not indispensable for the orosensory detection of dietary lipids in mice. J Lipid Res 2014; 56:369-78. [PMID: 25489006 DOI: 10.1194/jlr.m055202] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Implication of the long-chain fatty acid (LCFA) receptor GPR120, also termed free fatty acid receptor 4, in the taste-guided preference for lipids is a matter of debate. To further unravel the role of GPR120 in the "taste of fat", the present study was conducted on GPR120-null mice and their wild-type littermates. Using a combination of morphological [i.e., immunohistochemical staining of circumvallate papillae (CVP)], behavioral (i.e., two-bottle preference tests, licking tests and conditioned taste aversion) and functional studies [i.e., calcium imaging in freshly isolated taste bud cells (TBCs)], we show that absence of GPR120 in the oral cavity was not associated with changes in i) gross anatomy of CVP, ii) LCFA-mediated increases in intracellular calcium levels ([Ca(2+)]i), iii) preference for oily and LCFA solutions and iv) conditioned avoidance of LCFA solutions. In contrast, the rise in [Ca(2+)]i triggered by grifolic acid, a specific GPR120 agonist, was dramatically curtailed when the GPR120 gene was lacking. Taken together, these data demonstrate that activation of lingual GPR120 and preference for fat are not connected, suggesting that GPR120 expressed in TBCs is not absolutely required for oral fat detection in mice.
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Affiliation(s)
- Déborah Ancel
- NUTox, UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F21000 Dijon, France
| | - Arnaud Bernard
- NUTox, UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F21000 Dijon, France
| | | | - Akira Hirasawa
- Department of Pharmacogenomics, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo-ku, Kyoto 606-8501, Japan
| | - Gozoh Tsujimoto
- Department of Pharmacogenomics, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo-ku, Kyoto 606-8501, Japan
| | | | | | - Naim-Akhtar Khan
- NUTox, UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F21000 Dijon, France
| | - Philippe Besnard
- NUTox, UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F21000 Dijon, France
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182
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Abstract
Overconsumption of dietary fat contributes to the development of obesity and metabolic syndrome. Recent evidence suggests that high dietary fat may promote these metabolic states not only by providing calories but also by inducing impaired control of energy balance. In normal metabolic states, fat interacts with various organs or receptors to generate signals for the regulation of energy balance. Many of these interactions are impaired by high-fat diets or in obesity, contributing to the development or maintenance of obesity. These impairments may arise largely from fundamental alterations in the hypothalamus where all peripheral signals are integrated to regulate energy balance. This review focuses on various mechanisms by which fat is sensed at different stages of ingestion, circulation, storage, and utilization to regulate food intake, and how these individual mechanisms are altered by high-fat diets or in obesity.
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Affiliation(s)
- Jang H Youn
- Department of Physiology and Biophysics, University of Southern California Keck School of Medicine, Los Angeles, CA, USA,
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183
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Ancel D, Bernard A, Subramaniam S, Hirasawa A, Tsujimoto G, Passilly-Degrace P, Khan NA, Besnard P. O16: Le senseur lipidique GPR120 n’est pas indispensable pour la préférence aux lipides médiée par le goût chez la souris. NUTR CLIN METAB 2014. [DOI: 10.1016/s0985-0562(14)70592-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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184
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Suzuki A, Zhong H, Lee J, Martini S. Effect of Lipid Content on Saltiness Perception: A Psychophysical Study. J SENS STUD 2014. [DOI: 10.1111/joss.12121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A.H. Suzuki
- Department of Nutrition, Dietetics, and Food Sciences; Utah State University; Logan UT 84322-8700
| | - H. Zhong
- Glanbia R&D Center; Twin Falls ID
| | - J. Lee
- Department of Nutrition, Dietetics, and Food Sciences; Utah State University; Logan UT 84322-8700
| | - S. Martini
- Department of Nutrition, Dietetics, and Food Sciences; Utah State University; Logan UT 84322-8700
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185
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Moran BM, Abdel-Wahab YHA, Flatt PR, McKillop AM. Evaluation of the insulin-releasing and glucose-lowering effects of GPR120 activation in pancreatic β-cells. Diabetes Obes Metab 2014; 16:1128-39. [PMID: 24919766 DOI: 10.1111/dom.12330] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/02/2014] [Accepted: 06/10/2014] [Indexed: 01/17/2023]
Abstract
AIMS To assess the potency and selectivity of various GPR120 agonists and to determine the cellular localization of GPR120 in clonal β-cells and pancreatic islets. METHODS Insulin secretion and alterations in intracellular Ca(2+) and cAMP response to glucose and GPR120 agonists, including endogenous agonists α-linolenic acid (ALA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and a synthetic analogue (GW-9508), were examined using clonal pancreatic BRIN-BD11 cells, mouse pancreatic islets and in vivo studies using NIH Swiss mice. Cytotoxicity was assessed by lactate dehydrogenase release. Cellular localization of GPR120 was explored by double-staining immunohistochemistry. RESULTS The most potent and selective GPR120 agonist tested was ALA (half maximum effective concentration 1.2 × 10(-8) mol/l) with a maximum stimulation of insulin secretion of 53% at 10(-4) mol/l (p < 0.001) in BRIN-BD11 cells. Stimulation of insulin secretion was also observed with GW-9508 (6.4 × 10(-8) mol/l; 47%), EPA (7.9 × 10(-8) mol/l; 36%) and DHA (1.0 × 10(-7) mol/l; 50%). Results were corroborated by islet studies, with no evidence of cytotoxic effects. Dose-dependent insulin secretion by GPR120 agonists was glucose-sensitive and accompanied by significant elevations of intracellular Ca(2+) and cAMP. Immunocytochemistry showed GPR120 expression on BRIN-BD11 cells and was confined to islet β-cells with no distribution on α-cells. Administration of GPR120 agonists (0.1 µmol/kg body weight) in glucose tolerance studies significantly reduced plasma glucose and augmented insulin release in mice. CONCLUSIONS These results indicate that GPR120 is expressed on pancreatic β-cells and that agonists at this receptor are potent insulin secretagogues with therapeutic potential for type 2 diabetes.
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Affiliation(s)
- B M Moran
- Biomedical Sciences Research Institute, SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
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186
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Zhang ZQ, Shu G, Zhu XT, Wang LN, Fu Q, Hou LJ, Wang SB, Gao P, Xi QY, Zhang YL, Yu L, Lv JR, Jiang QY. Isolation and characterization of porcine circumvallate papillae cells. Acta Histochem 2014; 116:1313-22. [PMID: 25183665 DOI: 10.1016/j.acthis.2014.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/08/2014] [Accepted: 08/10/2014] [Indexed: 11/17/2022]
Abstract
Animal food intake is primarily controlled by appetite, which is affected by food quality, environment, and the management and status of animal health. Sensing of taste is mediated by taste receptor cells and is central to appetite. Taste receptor cells possess distinctive physiological characteristics that permit the recognition of various stimuli in foods. Thus, cultures of porcine circumvallate papillae cells provide a model for identification of the molecular and functional characteristics of taste receptor cells. In this study, we described the isolation and culture of porcine circumvallate papillae, using tissue explants and enzymatic digestion, and showed continuous viability and expression of pivotal taste marker proteins for more than 9 passages. In addition, cultured cells showed dramatic rises in intracellular calcium upon stimulation with several taste stimuli (sweet, umami, bitter, and fat). These cultures of porcine taste receptor cells provide a useful model for assessing taste preferences of pigs and may elucidate interactions between various taste stimuli.
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Affiliation(s)
- Zhi-Qi Zhang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Gang Shu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Tong Zhu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Li-Na Wang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Qiang Fu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Lian-Jie Hou
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Song-Bo Wang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Ping Gao
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Qian-Yun Xi
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yong-Liang Zhang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Lin Yu
- DadHank (Chengdu) Biotech. Corp. Wenjiang Cross-strait Technology Industry Development Park, Chengdu 611130, China
| | - Ji-Rong Lv
- DadHank (Chengdu) Biotech. Corp. Wenjiang Cross-strait Technology Industry Development Park, Chengdu 611130, China
| | - Qing-Yan Jiang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
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187
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188
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Moriyama R, Deura C, Imoto S, Nose K, Fukushima N. Expression of the long-chain fatty acid receptor GPR120 in the gonadotropes of the mouse anterior pituitary gland. Histochem Cell Biol 2014; 143:21-7. [PMID: 25112963 DOI: 10.1007/s00418-014-1257-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2014] [Indexed: 11/28/2022]
Abstract
G-protein-coupled receptor 120 (GPR120) has been known to be a receptor of long-chain fatty acids. Here, we investigated GPR120 expression in the mouse pituitary gland via real-time PCR, in situ hybridization, and immunohistochemistry. GPR120 mRNA was abundantly expressed in the pituitary gland of ad-lib fed animals. In situ hybridization and immunohistochemistry revealed GPR120 expression in the gonadotropes of the anterior pituitary gland, but not in thyrotropes, somatotropes, lactotropes, corticotropes, melanotropes, and the posterior pituitary gland. Furthermore, 24 h of fasting induced an increase in GPR120 mRNA expression in the pituitary gland. These results demonstrate that GPR120 in mouse pituitary gonadotropes is upregulated by fasting and that it may play a role in controlling gonadotropin secretion.
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Affiliation(s)
- Ryutaro Moriyama
- Laboratory of Molecular Neurobiology, Department of Life Science, Kinki University, 3-4-1 Kowakae, Higashiosaka, Osaka, 577-8502, Japan,
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189
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Zhang D, Leung PS. Potential roles of GPR120 and its agonists in the management of diabetes. DRUG DESIGN DEVELOPMENT AND THERAPY 2014; 8:1013-27. [PMID: 25114508 PMCID: PMC4122337 DOI: 10.2147/dddt.s53892] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Free fatty acids (FFAs) serve not only as nutrients that provide energy but also as extracellular signaling molecules that manipulate intracellular physiological events through FFA receptors (FFARs) such as FFAR4. FFAR4 is also known as G-protein coupled receptor 120 (GPR120). The main role of GPR120 is to elicit FFA regulation on metabolism homeostasis. GPR120 agonism correlates with prevention of the occurrence and development of metabolic disorders such as obesity and diabetes. GPR120 activation directly or indirectly inhibits inflammation, modulates hormone secretion from the gastrointestinal tract and pancreas, and regulates lipid and/or glucose metabolism in adipose, liver, and muscle tissues, which may help prevent obesity and diabetes. This review summarizes recent advances in physiological roles of GPR120 in preventing insulin resistance and protecting pancreatic islet function, and examines how resident GPR120 in the pancreas may be involved in modulating pancreatic islet function.
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Affiliation(s)
- Dan Zhang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
| | - Po Sing Leung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
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190
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Takahashi H, Rikimaru K, Kiyohara R, Yamaguchi S. Effect of Arachidonic Acid-enriched Oil Diet Supplementation on the Taste of Broiler Meat. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2014; 25:845-51. [PMID: 25049636 PMCID: PMC4093101 DOI: 10.5713/ajas.2011.11517] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/21/2012] [Accepted: 02/07/2012] [Indexed: 11/27/2022]
Abstract
To elucidate the relationship between the arachidonic acid (AA) content and the taste of broiler meat, the effects of AA-enriched oil (AAO) supplements on the fatty acid content and sensory perceptions of thigh meat were evaluated. Four types of oil, including corn oil (CO), a 1:1 mixture of AAO and palm oil (PO) (1/2 AAO), a 1:3 mixture of AAO and PO (1/4 AAO), and a 1:7 mixture of AAO and PO (1/8 AAO) were prepared. Each type of oil was mixed with silicate at a ratio of 7:3, and added to the diet at a final proportion of 5% of fresh matter. Broiler chickens were fed these diets for 1 wk before slaughter. In thigh meat, the AA content of the 1/2 and 1/4 AAO groups was significantly higher than that of the CO group. The AA content in thigh meat (y, mg/g) increased linearly with increasing dietary AAO content (x, g/100 g of diet), according to the equation y = 0.5674+0.4596× (r2 = 0.8454). The content of other fatty acids was not significantly different among the 4 diet groups. Sensory evaluation showed that the flavor intensity, umami (L-glutamate taste), kokumi (continuity, mouthfulness, and thickness), and aftertaste of the 1/2 and 1/4 AAO groups were significantly higher than that of the CO group. There were significant positive correlations between AA content in thigh meat and the flavor intensity, total taste intensity, umami, and aftertaste. These data suggest that the taste of broiler meat can be improved by the amount of dietary AA supplementation.
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Affiliation(s)
- H Takahashi
- Livestock Experiment Station, Akita Prefectural Agriculture Forestry and Fisheries Research Center, Daisen 019-1701, Japan
| | - K Rikimaru
- Livestock Experiment Station, Akita Prefectural Agriculture Forestry and Fisheries Research Center, Daisen 019-1701, Japan
| | - R Kiyohara
- Oils and Fats Fundamental Technology Laboratory, J-Oil Mills, Inc., Yokohama 230-0053, Japan
| | - S Yamaguchi
- Oils and Fats Fundamental Technology Laboratory, J-Oil Mills, Inc., Yokohama 230-0053, Japan
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191
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Cell mechanisms of gustatory lipids perception and modulation of the dietary fat preference. Biochimie 2014; 107 Pt A:11-4. [PMID: 24997404 DOI: 10.1016/j.biochi.2014.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 06/25/2014] [Indexed: 01/11/2023]
Abstract
Dietary lipids are usually responsible of several metabolic disorders. Recent compelling evidences suggest that there is a sixth taste modality, destined for the detection of oro-gustatory fats. The lipid-binding glycoprotein CD36, expressed by circumvallate papillae (CVP) of the mouse tongue, has been shown to be implicated in oro-gustatory perception of dietary lipids. We demonstrate that linoleic acid (LA) by activating sPLA2, cPLA2 and iPLA2 via CD36, produced arachidonic acid (AA) and lyso-phosphatidylcholine (Lyso-PC) which triggered Ca(2+) influx in CD36-positive taste bud cells (TBC), purified from mouse CVP. LA induced the production of Ca(2+) influx factor (CIF). CIF, AA and Lyso-PC exerted different actions on the opening of store-operated Ca2+ (SOC) channels, constituted of Orai proteins and regulated by STIM1, a sensor of Ca(2+) depletion in the endoplasmic reticulum. We observed that CIF and Lyso-PC opened Orai1 channels whereas AA-opened Ca(2+) channels were composed of Orai1/Orai3. STIM1 was found to regulate LA-induced CIF production and opening of both kinds of Ca(2+) channels. Furthermore, Stim1(-/-) mice lost the spontaneous preference for fat, observed in wild-type animals. Our results suggest that fatty acid-induced Ca(2+) signaling, regulated by STIM1 via CD36, might be implicated in oro-gustatory perception of dietary lipids and the spontaneous preference for fat. Other cell types are involved in, and external factors can influence this preference.
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192
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Stone VM, Dhayal S, Brocklehurst KJ, Lenaghan C, Sörhede Winzell M, Hammar M, Xu X, Smith DM, Morgan NG. GPR120 (FFAR4) is preferentially expressed in pancreatic delta cells and regulates somatostatin secretion from murine islets of Langerhans. Diabetologia 2014; 57:1182-91. [PMID: 24663807 PMCID: PMC4018485 DOI: 10.1007/s00125-014-3213-0] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 02/17/2014] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS The NEFA-responsive G-protein coupled receptor 120 (GPR120) has been implicated in the regulation of inflammation, in the control of incretin secretion and as a predisposing factor influencing the development of type 2 diabetes by regulation of islet cell apoptosis. However, there is still considerable controversy about the tissue distribution of GPR120 and, in particular, it remains unclear which islet cell types express this molecule. In the present study, we have addressed this issue by constructing a Gpr120-knockout/β-galactosidase (LacZ) knock-in (KO/KI) mouse to examine the distribution and functional role of GPR120 in the endocrine pancreas. METHODS A KO/KI mouse was generated in which exon 1 of the Gpr120 gene (also known as Ffar4) was replaced in frame by LacZ, thereby allowing for regulated expression of β-galactosidase under the control of the endogenous GPR120 promoter. The distribution of GPR120 was inferred from expression studies detecting β-galactosidase activity and protein production. Islet hormone secretion was measured from isolated mouse islets treated with selective GPR120 agonists. RESULTS β-galactosidase activity was detected as a surrogate for GPR120 expression exclusively in a small population of islet endocrine cells located peripherally within the islet mantle. Immunofluorescence analysis revealed co-localisation with somatostatin suggesting that GPR120 is preferentially produced in islet delta cells. In confirmation of this, glucose-induced somatostatin secretion was inhibited by a range of selective GPR120 agonists. This response was lost in GPR120-knockout mice. CONCLUSIONS/INTERPRETATION The results imply that GPR120 is selectively present within the delta cells of murine islets and that it regulates somatostatin secretion.
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Affiliation(s)
- Virginia M. Stone
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building, Barrack Road, Exeter, EX2 5DW UK
- Centre for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Shalinee Dhayal
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building, Barrack Road, Exeter, EX2 5DW UK
| | | | | | | | - Mårten Hammar
- R&D, Cardiovascular and Metabolic Diseases, AstraZeneca, Mölndal, Sweden
| | - Xiufeng Xu
- R&D, Cardiovascular and Metabolic Diseases, AstraZeneca, Mölndal, Sweden
| | - David M. Smith
- R&D, Cardiovascular and Metabolic Diseases, AstraZeneca, Mölndal, Sweden
| | - Noel G. Morgan
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building, Barrack Road, Exeter, EX2 5DW UK
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193
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Increased Levels of Extracellular Dopamine in the Nucleus Accumbens and Amygdala of Rats by Ingesting a Low Concentration of a Long-Chain Fatty Acid. Biosci Biotechnol Biochem 2014; 77:2175-80. [DOI: 10.1271/bbb.130234] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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194
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Pepino MY, Kuda O, Samovski D, Abumrad NA. Structure-function of CD36 and importance of fatty acid signal transduction in fat metabolism. Annu Rev Nutr 2014; 34:281-303. [PMID: 24850384 DOI: 10.1146/annurev-nutr-071812-161220] [Citation(s) in RCA: 398] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CD36 (cluster of differentiation 36) is a scavenger receptor that functions in high-affinity tissue uptake of long-chain fatty acids (FAs) and contributes under excessive fat supply to lipid accumulation and metabolic dysfunction. This review describes recent evidence regarding the CD36 FA binding site and a potential mechanism for FA transfer. It also presents the view that CD36 and FA signaling coordinate fat utilization, a view that is based on newly identified CD36 actions that involve oral fat perception, intestinal fat absorption, secretion of the peptides cholecystokinin and secretin, regulation of hepatic lipoprotein output, activation of beta oxidation by muscle, and regulation of the production of the FA-derived bioactive eicosanoids. Thus abnormalities of fat metabolism and the associated pathology might involve dysfunction of CD36-mediated signal transduction in addition to the changes in FA uptake.
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195
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Sclafani A, Ackroff K. Maltodextrin and fat preference deficits in "taste-blind" P2X2/P2X3 knockout mice. Chem Senses 2014; 39:507-14. [PMID: 24833134 DOI: 10.1093/chemse/bju019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Adenosine triphosphate is a critical neurotransmitter in the gustatory response to the 5 primary tastes in mice. Genetic deletion of the purinergic P2X2/P2X3 receptor greatly reduces the neural and behavioral response to prototypical primary taste stimuli. In this study, we examined the behavioral response of P2X double knockout mice to maltodextrin and fat stimuli, which appear to activate additional taste channels. P2X double knockout and wild-type mice were given 24-h choice tests (vs. water) with ascending concentrations of Polycose and Intralipid. In Experiment 1, naive double knockout mice, unlike wild-type mice, were indifferent to dilute (0.5-4%) Polycose solutions but preferred concentrated (8-32%) Polycose to water. In a retest, the Polycose-experienced double knockout mice, like wild-type mice, preferred all Polycose concentrations. In Experiment 2, naive double knockout mice, unlike wild-type mice, were indifferent to dilute (0.313-2.5%) Intralipid emulsions but preferred concentrated (5-20%) Intralipid to water. In a retest, the fat-experienced double knockout mice, like wild-type mice, strongly preferred 0.313-5% Intralipid to water. These results indicate that the inherent preferences of mice for maltodextrin and fat are dependent upon adenosine triphosphate taste cell signaling. With experience, however, P2X double knockout mice develop strong preferences for the nontaste flavor qualities of maltodextrin and fat conditioned by the postoral actions of these nutrients.
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Affiliation(s)
- Anthony Sclafani
- Department of Psychology, Brooklyn College of CUNY, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
| | - Karen Ackroff
- Department of Psychology, Brooklyn College of CUNY, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
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196
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Abstract
Five canonical tastes, bitter, sweet, umami (amino acid), salty, and sour (acid), are detected by animals as diverse as fruit flies and humans, consistent with a near-universal drive to consume fundamental nutrients and to avoid toxins or other harmful compounds. Surprisingly, despite this strong conservation of basic taste qualities between vertebrates and invertebrates, the receptors and signaling mechanisms that mediate taste in each are highly divergent. The identification over the last two decades of receptors and other molecules that mediate taste has led to stunning advances in our understanding of the basic mechanisms of transduction and coding of information by the gustatory systems of vertebrates and invertebrates. In this Review, we discuss recent advances in taste research, mainly from the fly and mammalian systems, and we highlight principles that are common across species, despite stark differences in receptor types.
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Affiliation(s)
- Emily R Liman
- Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Yali V Zhang
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Craig Montell
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA; Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
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197
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Tucker RM, Mattes RD, Running CA. Mechanisms and effects of "fat taste" in humans. Biofactors 2014; 40:313-26. [PMID: 24591077 DOI: 10.1002/biof.1162] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 02/18/2014] [Indexed: 12/11/2022]
Abstract
Evidence supporting a "taste" cue from fat in the oral cavity continues to accrue. The proposed stimuli for fat taste, non-esterified fatty acids (NEFA), are released from food through hydrolytic rancidity and lipase activity derived from foods or saliva. NEFA must then be released from the food matrix, negotiate the aqueous environment to reach taste cell surfaces, and interact with receptors such as CD36 and GPR120 or diffuse across cell membranes to initiate a taste signal. Knowledge of these processes in non-gustatory tissues should inform understanding of taste responses to NEFA. Additionally, downstream effects of oral triglyceride exposure have been observed in numerous studies. Data specific to effects of NEFA versus triglyceride are scarce, but modified sham feeding trials with triglyceride document cephalic phase responses including elevations in serum lipids and insulin as well as potential, but debated, effects on gut peptides, appetite, and thermogenesis. In this review, we highlight the mechanisms by which NEFA migrate to and interact with taste cells, and then we examine physiological responses to oral fat exposure.
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Affiliation(s)
- Robin M Tucker
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
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198
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Darling RA, Zhao H, Kinch D, Li AJ, Simasko SM, Ritter S. Mercaptoacetate and fatty acids exert direct and antagonistic effects on nodose neurons via GPR40 fatty acid receptors. Am J Physiol Regul Integr Comp Physiol 2014; 307:R35-43. [PMID: 24760994 DOI: 10.1152/ajpregu.00536.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-mercaptoacetate (MA) is a drug known to block mitochondrial oxidation of medium- and long-chain fatty acids (FAs) and to stimulate feeding. Because MA-induced feeding is vagally dependent, it has been assumed that the feeding response is mediated by MA's antimetabolic action at a peripheral, vagally innervated site. However, MA's site of action has not yet been identified. Therefore, we used fluorescent calcium measurements in isolated neurons from rat nodose ganglia to determine whether MA has direct effects on vagal sensory neurons. We found that MA alone did not alter cytosolic calcium concentrations in nodose neurons. However, MA (60 μM to 6 mM) significantly decreased calcium responses to both linoleic acid (LA; 10 μM) and caprylic acid (C8; 10 μM) in all neurons responsive to LA and C8. GW9508 (40 μM), an agonist of the FA receptor, G protein-coupled receptor 40 (GPR40), also increased calcium levels almost exclusively in FA-responsive neurons. MA significantly inhibited this response to GW9508. MA did not inhibit calcium responses to serotonin, high K(+), or capsaicin, which do not utilize GPRs, or to CCK, which acts on a different GPR. GPR40 was detected in nodose ganglia by RT-PCR. Results suggest that FAs directly activate vagal sensory neurons via GPR40 and that MA antagonizes this effect. Thus, we propose that MA's nonmetabolic actions on GPR40 membrane receptors, expressed by multiple peripheral tissues in addition to the vagus nerve, may contribute to or mediate MA-induced stimulation of feeding.
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Affiliation(s)
- Rebecca A Darling
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Huan Zhao
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Dallas Kinch
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Ai-Jun Li
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Steven M Simasko
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Sue Ritter
- Program in Neuroscience, Washington State University, Pullman, Washington
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199
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Suckow AT, Polidori D, Yan W, Chon S, Ma JY, Leonard J, Briscoe CP. Alteration of the glucagon axis in GPR120 (FFAR4) knockout mice: a role for GPR120 in glucagon secretion. J Biol Chem 2014; 289:15751-63. [PMID: 24742677 DOI: 10.1074/jbc.m114.568683] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
GPR40 (FFAR1) and GPR120 (FFAR4) are G-protein-coupled receptors (GPCRs) that are activated by long chain fatty acids (LCFAs). GPR40 is expressed at high levels in islets and mediates the ability of LCFAs to potentiate glucose-stimulated insulin secretion (GSIS). GPR120 is expressed at high levels in colon, adipose, and pituitary, and at more modest levels in pancreatic islets. The role of GPR120 in islets has not been explored extensively. Here, we confirm that saturated (e.g. palmitic acid) and unsaturated (e.g. docosahexaenoic acid (DHA)) LCFAs engage GPR120 and demonstrate that palmitate- and DHA-potentiated glucagon secretion are greatly reduced in isolated GPR120 KO islets. Remarkably, LCFA potentiated glucagon secretion is similarly reduced in GPR40 KO islets. Compensatory changes in mRNA expression of GPR120 in GPR40 KO islets, and vice versa, do not explain that LCFA potentiated glucagon secretion seemingly involves both receptors. LCFA-potentiated GSIS remains intact in GPR120 KO islets. Consistent with previous reports, GPR120 KO mice are hyperglycemic and glucose intolerant; however, our KO mice display evidence of a hyperactive counter-regulatory response rather than insulin resistance during insulin tolerance tests. An arginine stimulation test and a glucagon challenge confirmed both increases in glucagon secretion and liver glucagon sensitivity in GPR120 KO mice relative to WT mice. Our findings demonstrate that GPR120 is a nutrient sensor that is activated endogenously by both saturated and unsaturated long chain fatty acids and that an altered glucagon axis likely contributes to the impaired glucose homeostasis observed in GPR120 KO mice.
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Affiliation(s)
- Arthur T Suckow
- From Janssen Research & Development, LLC, San Diego, California 92121
| | - David Polidori
- From Janssen Research & Development, LLC, San Diego, California 92121
| | - Wen Yan
- From Janssen Research & Development, LLC, San Diego, California 92121
| | - Suhyoun Chon
- From Janssen Research & Development, LLC, San Diego, California 92121
| | - Jing Ying Ma
- From Janssen Research & Development, LLC, San Diego, California 92121
| | - James Leonard
- From Janssen Research & Development, LLC, San Diego, California 92121
| | - Celia P Briscoe
- From Janssen Research & Development, LLC, San Diego, California 92121
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200
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Massen JJM, Dusch K, Eldakar OT, Gallup AC. A thermal window for yawning in humans: yawning as a brain cooling mechanism. Physiol Behav 2014; 130:145-8. [PMID: 24721675 DOI: 10.1016/j.physbeh.2014.03.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 02/24/2014] [Accepted: 03/31/2014] [Indexed: 12/23/2022]
Abstract
The thermoregulatory theory of yawning posits that yawns function to cool the brain in part due to counter-current heat exchange with the deep inhalation of ambient air. Consequently, yawning should be constrained to an optimal thermal zone or range of temperature, i.e., a thermal window, in which we should expect a lower frequency at extreme temperatures. Previous research shows that yawn frequency diminishes as ambient temperatures rise and approach body temperature, but a lower bound to the thermal window has not been demonstrated. To test this, a total of 120 pedestrians were sampled for susceptibly to self-reported yawn contagion during distinct temperature ranges and seasons (winter: 1.4°C, n=60; summer: 19.4°C, n=60). As predicted, the proportion of pedestrians reporting yawning was significantly lower during winter than in summer (18.3% vs. 41.7%), with temperature being the only significant predictor of these differences across seasons. The underlying mechanism for yawning in humans, both spontaneous and contagious, appears to be involved in brain thermoregulation.
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Affiliation(s)
- Jorg J M Massen
- Department of Cognitive Biology, University of Vienna, Vienna, Austria.
| | - Kim Dusch
- Department of Education, University of Vienna, Vienna, Austria
| | - Omar Tonsi Eldakar
- Farquhar College of Arts and Sciences, Nova Southeastern University, Ft. Lauderdale, USA
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