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Savory Signaling: T1R Umami Receptor Modulates Endoplasmic Reticulum Calcium Store Content and Release Dynamics in Airway Epithelial Cells. Nutrients 2023; 15:nu15030493. [PMID: 36771200 PMCID: PMC9919336 DOI: 10.3390/nu15030493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/10/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
Abstract
T1Rs are expressed in solitary chemosensory cells of the upper airway where they detect apical glucose levels and repress bitter taste receptor Ca2+ signaling pathways. Microbial growth leads to a decrease in apical glucose levels. T1Rs detect this change and liberate bitter taste receptor signaling, initiating an innate immune response to both kill and expel pathogens through releasing antimicrobial peptides and increasing nitric oxide production and ciliary beat frequency. However, chronic inflammation due to disease, smoking, or viral infections causes a remodeling of the epithelial airway. The resulting squamous metaplasia causes a loss of multi-ciliated cells and solitary chemosensory cells, replaced by basal epithelial cells. To understand how T1R function is altered during disease, we used basal epithelial cells as a model to study the function of T1R3 on Ca2+ signaling dynamics. We found that both T1R1 and T1R3 detect amino acids and signal via cAMP, increasing the responsiveness of the cells to Ca2+ signaling stimuli. Either knocking down T1R1/3 or treating wild-type cells with MEM amino acids caused a reduction in ER Ca2+ content through a non-cAMP signaled pathway. Treatment with amino acids led to a reduction in downstream denatonium-induced Ca2+-signaled caspase activity. Thus, amino acids may be used to reduce unwanted apoptosis signaling in treatments containing bitter compounds.
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Ma L, Tian X, Xi F, He Y, Li D, Sun J, Yuan T, Li K, Fan L, Zhang C, Yang G, Yu T. Ablation of Tas1r1 Reduces Lipid Accumulation Through Reducing the de Novo Lipid Synthesis and Improving Lipid Catabolism in Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:10248-10258. [PMID: 35968935 DOI: 10.1021/acs.jafc.2c02077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Amino acid sensing plays an important role in regulating lipid metabolism by sensing amino acid nutrient disturbance. T1R1 (umami taste receptor, type 1, member 1) is a membrane G protein-coupled receptor that senses amino acids. Tas1r1-knockout (KO) mice were used to explore the function of umami receptors in lipid metabolism. Compared with wild-type (WT) mice, Tas1r1-KO mice showed decreased fat mass (P < 0.05) and adipocyte size, lower liver triglyceride (7.835 ± 0.809 vs 12.463 ± 0.916 mg/g WT, P = 0.013) and total cholesterol levels (0.542 ± 0.109 vs 1.472 ± 0.044 mmol/g WT, P < 0.001), and reduced lipogenesis gene expressions in adipose and liver tissues. Targeted liver amino acid metabolomics showed that the amino acid content of Tas1r1-KO mice was significantly decreased, which was consistent with the branched-chain ketoacid dehydrogenase protein levels. Proteomics analysis showed that the upregulated proteins were enriched in lipid and steroid metabolism pathways, and parallel reaction monitoring results illustrated that Tas1r1 ablation promoted lipid catabolism through oxysterol 7 α-hydroxylase and insulin-like growth factor binding protein 2. In summary, Tas1r1 disruption in mice could reduce lipid accumulation by reducing de novo lipid synthesis and improving lipid catabolism.
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Affiliation(s)
- Lu Ma
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Xuekai Tian
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Fengxue Xi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yulin He
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Dong Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jingchun Sun
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Tiantian Yuan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Ke Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Lin Fan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Chunlei Zhang
- Institute of Cellular and Molecular Biology, Collage of Life Sciences, Jiangsu Normal University, Xuzhou 221116, Jiangsu, China
| | - Gongshe Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Taiyong Yu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
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Patt J, Alenfelder J, Pfeil EM, Voss JH, Merten N, Eryilmaz F, Heycke N, Rick U, Inoue A, Kehraus S, Deupi X, Müller CE, König GM, Crüsemann M, Kostenis E. An experimental strategy to probe Gq contribution to signal transduction in living cells. J Biol Chem 2021; 296:100472. [PMID: 33639168 PMCID: PMC8024710 DOI: 10.1016/j.jbc.2021.100472] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
Heterotrimeric G protein subunits Gαq and Gα11 are inhibited by two cyclic depsipeptides, FR900359 (FR) and YM-254890 (YM), both of which are being used widely to implicate Gq/11 proteins in the regulation of diverse biological processes. An emerging major research question therefore is whether the cellular effects of both inhibitors are on-target, that is, mediated via specific inhibition of Gq/11 proteins, or off-target, that is, the result of nonspecific interactions with other proteins. Here we introduce a versatile experimental strategy to discriminate between these possibilities. We developed a Gαq variant with preserved catalytic activity, but refractory to FR/YM inhibition. A minimum of two amino acid changes were required and sufficient to achieve complete inhibitor resistance. We characterized the novel mutant in HEK293 cells depleted by CRISPR–Cas9 of endogenous Gαq and Gα11 to ensure precise control over the Gα-dependent cellular signaling route. Using a battery of cellular outcomes with known and concealed Gq contribution, we found that FR/YM specifically inhibited cellular signals after Gαq introduction via transient transfection. Conversely, both inhibitors were inert across all assays in cells expressing the drug-resistant variant. These findings eliminate the possibility that inhibition of non-Gq proteins contributes to the cellular effects of the two depsipeptides. We conclude that combined application of FR or YM along with the drug-resistant Gαq variant is a powerful in vitro strategy to discern on-target Gq against off-target non-Gq action. Consequently, it should be of high value for uncovering Gq input to complex biological processes with high accuracy and the requisite specificity.
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Affiliation(s)
- Julian Patt
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Judith Alenfelder
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Eva Marie Pfeil
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Jan Hendrik Voss
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical and Medicinal Chemistry, University of Bonn, Bonn, Germany
| | - Nicole Merten
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Funda Eryilmaz
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Nina Heycke
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Uli Rick
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Stefan Kehraus
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Xavier Deupi
- Laboratory of Biomolecular Research and Condensed Matter Theory Group, Paul Scherrer Institute, Villigen, Switzerland
| | - Christa E Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical and Medicinal Chemistry, University of Bonn, Bonn, Germany
| | - Gabriele M König
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Max Crüsemann
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Evi Kostenis
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany.
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Effect of Methionine Restriction on Aging: Its Relationship to Oxidative Stress. Biomedicines 2021; 9:biomedicines9020130. [PMID: 33572965 PMCID: PMC7911310 DOI: 10.3390/biomedicines9020130] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 02/06/2023] Open
Abstract
Enhanced oxidative stress is closely related to aging and impaired metabolic health and is influenced by diet-derived nutrients and energy. Recent studies have shown that methionine restriction (MetR) is related to longevity and metabolic health in organisms from yeast to rodents. The effect of MetR on lifespan extension and metabolic health is mediated partially through a reduction in oxidative stress. Methionine metabolism is involved in the supply of methyl donors such as S-adenosyl-methionine (SAM), glutathione synthesis and polyamine metabolism. SAM, a methionine metabolite, activates mechanistic target of rapamycin complex 1 and suppresses autophagy; therefore, MetR can induce autophagy. In the process of glutathione synthesis in methionine metabolism, hydrogen sulfide (H2S) is produced through cystathionine-β-synthase and cystathionine-γ-lyase; however, MetR can induce increased H2S production through this pathway. Similarly, MetR can increase the production of polyamines such as spermidine, which are involved in autophagy. In addition, MetR decreases oxidative stress by inhibiting reactive oxygen species production in mitochondria. Thus, MetR can attenuate oxidative stress through multiple mechanisms, consequently associating with lifespan extension and metabolic health. In this review, we summarize the current understanding of the effects of MetR on lifespan extension and metabolic health, focusing on the reduction in oxidative stress.
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Kitada M, Xu J, Ogura Y, Monno I, Koya D. Mechanism of Activation of Mechanistic Target of Rapamycin Complex 1 by Methionine. Front Cell Dev Biol 2020; 8:715. [PMID: 32850834 PMCID: PMC7431653 DOI: 10.3389/fcell.2020.00715] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/13/2020] [Indexed: 12/25/2022] Open
Abstract
Nutrients are closely involved in the regulation of lifespan and metabolic health. Cellular activities, such as the regulation of metabolism, growth, and aging, are mediated by a network of nutrients and nutrient-sensing pathways. Among the nutrient-sensing pathways, the mechanistic target of rapamycin complex 1 (mTORC1) acts as the central regulator of cellular functions, which include autophagy. Autophagy plays a significant role in the removal of protein aggregates and damaged or excess organelles, including mitochondria, to maintain intracellular homeostasis, which is involved in lifespan extension and cardiometabolic health. Moreover, dietary methionine restriction may have a beneficial effect on lifespan extension and metabolic health. In contrast, methionine may activate mTORC1 and suppress autophagy. As the mechanism of methionine sensing on mTORC1, SAMTOR was identified as a sensor of S-adenosyl methionine (SAM), a metabolite of methionine, in the cytoplasm. Conversely, methionine may activate the mTORC1 signaling pathway through the activation of phosphatase 2A (PP2A) because of increased methylation in response to intracellular SAM levels. In this review, we summarized the recent findings regarding the mechanism via which methionine activates mTORC1.
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Affiliation(s)
- Munehiro Kitada
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan.,Division of Anticipatory Molecular Food Science and Technology, Medical Research Institute, Kanazawa Medical University, Uchinada, Japan
| | - Jing Xu
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan
| | - Yoshio Ogura
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan
| | - Itaru Monno
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan
| | - Daisuke Koya
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan.,Division of Anticipatory Molecular Food Science and Technology, Medical Research Institute, Kanazawa Medical University, Uchinada, Japan
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Abstract
Heterotrimeric G proteins are the core upstream elements that transduce and amplify the cellular signals from G protein-coupled receptors (GPCRs) to intracellular effectors. GPCRs are the largest family of membrane proteins encoded in the human genome and are the targets of about one-third of prescription medicines. However, to date, no single therapeutic agent exerts its effects via perturbing heterotrimeric G protein function, despite a plethora of evidence linking G protein malfunction to human disease. Several recent studies have brought to light that the Gq family-specific inhibitor FR900359 (FR) is unexpectedly efficacious in silencing the signaling of Gq oncoproteins, mutant Gq variants that mostly exist in the active state. These data not only raise the hope that researchers working in drug discovery may be able to potentially strike Gq oncoproteins from the list of undruggable targets, but also raise questions as to how FR achieves its therapeutic effect. Here, we place emphasis on these recent studies and explain why they expand our pharmacological armamentarium for targeting Gq protein oncogenes as well as broaden our mechanistic understanding of Gq protein oncogene function. We also highlight how this novel insight impacts the significance and utility of using G(q) proteins as targets in drug discovery efforts.
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Affiliation(s)
- Evi Kostenis
- Section of Molecular, Cellular and Pharmacobiology, Institute of Pharmaceutical Biology, Nussallee 6, 53115 Bonn, Germany.
| | - Eva Marie Pfeil
- Section of Molecular, Cellular and Pharmacobiology, Institute of Pharmaceutical Biology, Nussallee 6, 53115 Bonn, Germany
| | - Suvi Annala
- Section of Molecular, Cellular and Pharmacobiology, Institute of Pharmaceutical Biology, Nussallee 6, 53115 Bonn, Germany
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7
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Liu S, Xu M, Zhu C, Zhao Q, Zhou F. Taste receptor T1R1/T1R3 promotes the tumoricidal activity of hepatic CD49a + CD49b - natural killer cells. Eur J Immunol 2018; 48:2031-2041. [PMID: 30259960 DOI: 10.1002/eji.201847688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/05/2018] [Accepted: 09/27/2018] [Indexed: 12/15/2022]
Abstract
Natural Killer (NK) cell-based immunotherapy is a promising approach to treat hepatocellular carcinoma (HCC). The mechanisms underlying the regulation of NK cell activity are not completely understood. In this research, we identified the expression of taste receptor type 1 member 1 (T1R1) and taste receptor type 1 member 3 (T1R3) in a subset of hepatic NK cells in a mouse HCC model. T1R1 and T1R3 were selectively expressed in CD49a+ CD49b- NK cells in livers with HCC. In the in vitro cytotoxicity assay, amino acids promoted the tumoricidal effect of CD49a+ CD49b- NK cells through increasing the production of perforin, granzyme B and IFN-γ. Furthermore, using a lentivirus to induce the expression of exogenous T1R1 and T1R3 in normal hepatic NK cells, we found that amino acids enhanced NK cell-mediated cytotoxicity on tumor cells through the T1R1/T1R3 receptor, as demonstrated by more tumor cell lysis, up-regulation of perforin and granzyme B in comparison with control NK cells. In addition, amino acids activated Akt and mechanistic target of rapamycin complex 1 (mTORC1) signaling in NK cells through T1R1/T1R3 receptor. T-bet expression in NK cells was also increased by amino acid treatment. Therefore, T1R1/T1R3 receptor promotes the tumoricidal activity of hepatic CD49a+ CD49b- NK cells.
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Affiliation(s)
- Shaoping Liu
- Medical Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Min Xu
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chengliang Zhu
- Department of Clinical Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qiu Zhao
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory for Intestinal and Colorectal Diseases, Wuhan, China
| | - Feng Zhou
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory for Intestinal and Colorectal Diseases, Wuhan, China
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Zhou Y, Zhou Z, Peng J, Loor JJ. Methionine and valine activate the mammalian target of rapamycin complex 1 pathway through heterodimeric amino acid taste receptor (TAS1R1/TAS1R3) and intracellular Ca 2+ in bovine mammary epithelial cells. J Dairy Sci 2018; 101:11354-11363. [PMID: 30268610 DOI: 10.3168/jds.2018-14461] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 08/14/2018] [Indexed: 11/19/2022]
Abstract
Amino acids play a key role in regulating milk protein synthesis partly through activation of the mammalian target of rapamycin (mTOR) signaling pathway. However, the involvement of extracellular AA sensing receptors in this process is not well understood. In nonruminants, it is well established that the AA taste 1 receptor member 1/3 (TAS1R1/TAS1R3) heterodimer contributes to the sensing of most l-AA. Whether this receptor is functional in bovine mammary cells is unknown. The objective of this study was to determine essential AA signaling through TAS1R1/TAS1R3 and their roles in regulating mTOR signaling pathway and casein mRNA abundance in primary bovine mammary epithelial cells and the Mac-T cell line. The bovine mammary epithelial cells were stimulated with complete Dulbecco's modified Eagle's medium (+EAA), medium without EAA (-EAA), or medium supplemented with only 1 of the 10 essential AA, respectively. The nonessential AA levels were the same across all treatments. Small interference RNA targeting TAS1R1 were designed and transfected into bovine primary mammary epithelial cells (bPMEC). Supplementation of a complete mixture of essential AA or Arg, Val, Leu, His, Phe, Met, and Ile individually led to greater mTOR phosphorylation. Phosphorylation of ribosomal protein S6 kinase β-1 was greater in the presence of Val, Leu, Trp, Met, and Ile. Valine, Leu, Met, and Ile led to greater eIF4E-binding protein 1 phosphorylation. Although +EAA and a few individual AA tested induced increases in intracellular calcium, Met and Val were the most potent. Knockdown of TAS1R1 decreased intracellular calcium in bPMEC cultured with both Val and Met. Phosphorylation of mTOR, ribosomal protein S6 kinase β-1, and eIF4E-binding protein 1 was lower when TAS1R1 was knocked-down in bPMEC supplemented with Val and Met. In addition, small interference RNA silencing of TAS1R1 resulted in lower β-casein (CSN2) abundance. The TAS1R1/TAS1R3 receptor may sense extracellular AA and activate mTOR signaling in bovine mammary cells, likely by elevating intracellular calcium concentration. This mechanism appears to have a role in Met- and Val-induced changes in CSN2 mRNA abundance. Further in vivo studies will have to be performed to assess the relevance of this mechanism in the mammary gland.
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Affiliation(s)
- Y Zhou
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan, Hubei, China 430070; Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
| | - Z Zhou
- Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634.
| | - J Peng
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan, Hubei, China 430070
| | - J J Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801.
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Zhou L, Huang W, Xu Y, Gao C, Zhang T, Guo M, Liu Y, Ding J, Qin L, Xu Z, Long Y, Xu Y. Sweet Taste Receptors Mediated ROS-NLRP3 Inflammasome Signaling Activation: Implications for Diabetic Nephropathy. J Diabetes Res 2018; 2018:7078214. [PMID: 29675433 PMCID: PMC5838486 DOI: 10.1155/2018/7078214] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 12/07/2017] [Accepted: 12/25/2017] [Indexed: 01/14/2023] Open
Abstract
Previous studies demonstrated that ROS-NLRP3 inflammasome signaling activation was involved in the pathogenesis of diabetic nephropathy (DN). Recent research has shown that sweet taste receptors (STRs) are important sentinels of innate immunity. Whether high glucose primes ROS-NLRP3 inflammasome signaling via STRs is unclear. In this study, diabetic mouse model was induced by streptozotocin (STZ) in vivo; mouse glomerular mesangial cells (GMCs) and human proximal tubular cells were stimulated by high glucose (10, 20, and 30 mmol/L) in vitro; STR inhibitor lactisole was used as an intervention reagent to evaluate the role and mechanism of the STRs in the pathogenesis of DN. Our results showed that the expression of STRs and associated signaling components (Gα-gustducin, PLCβ2, and TRPM5) was obviously downregulated under the condition of diabetes in vivo and in vitro. Furthermore, lactisole significantly mitigated the production of intracellular ROS and reversed the high glucose-induced decrease of Ca2+ and the activation of NLRP3 inflammasome signaling in vitro (p < 0.05). These combined results support the hypothesis that STRs could be involved in the activation of ROS-NLRP3 inflammasome signaling in the pathogenesis of DN, suggesting that STRs may act as new therapeutic targets of DN.
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Affiliation(s)
- Luping Zhou
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- The Graduate School of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Wei Huang
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- Faculty of Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
| | - Youhua Xu
- Faculty of Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
| | - Chenlin Gao
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- Faculty of Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
| | - Ting Zhang
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- The Graduate School of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Man Guo
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- The Graduate School of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Yan Liu
- Faculty of Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, China
| | - Jingya Ding
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- The Graduate School of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Ludan Qin
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- The Graduate School of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Zihao Xu
- The Graduate School of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Yang Long
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Yong Xu
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, China
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Shi J, Wang S, Ke Q, Lin J, Zheng Y, Wu S, Huang Z, Lin W. T1R1/T1R3 Taste Receptor Suppresses Granulocyte-Mediated Neuroinflammation after Spinal Cord Injury. J Neurotrauma 2017; 34:2353-2363. [PMID: 28474538 DOI: 10.1089/neu.2016.4952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
As an active and predominant blood leukocyte population, granulocytes infiltrate into injured spinal cord and produce pro-inflammatory mediators to aggravate neuroinflammation. In the current study, we identify the role of the T1R1/T1R3 receptor in granulocyte-mediated neuroinflammation in a rat spinal cord injury (SCI) model. We found that T1R1 and T1R3 were substantially expressed in both circulating and infiltrating granulocytes. In vitro stimulation of T1R1/T1R3 receptor with L-serine notably reduced production of reactive oxygen species (ROS) and several pro-inflammatory cytokines. To evaluate the role of T1R1/T1R3 receptor in vivo, gurmarin, a selective T1R3 inhibitor, was injected into rats before and after SCI. Gurmarin administration significantly upregulated expression of interleukin (IL)-1β, IL-6, myeloperoxidase, and matrix metallopeptidase 9, as well as production of ROS in infiltrating granulocytes. Signal pathway analysis revealed that gurmarin promoted nuclear factor (NF)-κβ signaling in infiltrating granulocytes. Consistently, cell apoptosis and inflammatory mediator levels at the injury sites were increased by gurmarin, together with higher T lymphocyte recruitment. Our research indicates that the T1R1/T1R3 receptor is an anti-inflammatory receptor for infiltrating granulocytes after SCI. Simulation of T1R1/T1R3 receptor might be a prospective, or at least a supplemental, therapeutic approach to controlling neuroinflammation to promote functional recovery.
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Affiliation(s)
- Jinxing Shi
- 1 Department of Orthopedic Surgery, the Second Affiliated Hospital, Fujian Medical University , Quanzhou, China
| | - Siyuan Wang
- 1 Department of Orthopedic Surgery, the Second Affiliated Hospital, Fujian Medical University , Quanzhou, China
| | - Qingfeng Ke
- 1 Department of Orthopedic Surgery, the Second Affiliated Hospital, Fujian Medical University , Quanzhou, China
| | - Jianhua Lin
- 2 Department of Orthopedic Surgery, the First Affiliated Hospital, Fujian Medical University , Fuzhou, China
| | - Yuhui Zheng
- 1 Department of Orthopedic Surgery, the Second Affiliated Hospital, Fujian Medical University , Quanzhou, China
| | - Shiqiang Wu
- 1 Department of Orthopedic Surgery, the Second Affiliated Hospital, Fujian Medical University , Quanzhou, China
| | - Zida Huang
- 2 Department of Orthopedic Surgery, the First Affiliated Hospital, Fujian Medical University , Fuzhou, China
| | - Wenping Lin
- 1 Department of Orthopedic Surgery, the Second Affiliated Hospital, Fujian Medical University , Quanzhou, China
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11
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Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
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Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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12
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Guerra ML, Kalwat MA, McGlynn K, Cobb MH. Sucralose activates an ERK1/2-ribosomal protein S6 signaling axis. FEBS Open Bio 2017; 7:174-186. [PMID: 28174684 PMCID: PMC5292669 DOI: 10.1002/2211-5463.12172] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/13/2016] [Accepted: 11/28/2016] [Indexed: 12/20/2022] Open
Abstract
The sweetener sucralose can signal through its GPCR receptor to induce insulin secretion from pancreatic β cells, but the downstream signaling pathways involved are not well‐understood. Here we measure responses to sucralose, glucagon‐like peptide 1, and amino acids in MIN6 β cells. Our data suggest a signaling axis, whereby sucralose induces calcium and cAMP, activation of ERK1/2, and site‐specific phosphorylation of ribosomal protein S6. Interestingly, sucralose acted independently of mTORC1 or ribosomal S6 kinase (RSK). These results suggest that sweeteners like sucralose can influence β‐cell responses to secretagogues like glucose through metabolic as well as GPCR‐mediated pathways. Future investigation of novel sweet taste receptor signaling pathways in β cells will have implications for diabetes and other emergent fields involving these receptors.
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Affiliation(s)
- Marcy L Guerra
- Department of Pharmacology UT Southwestern Medical Center Dallas TX USA; Present address: Stem Synergy Therapeutics Nashville TN USA
| | - Michael A Kalwat
- Department of Pharmacology UT Southwestern Medical Center Dallas TX USA
| | - Kathleen McGlynn
- Department of Pharmacology UT Southwestern Medical Center Dallas TX USA
| | - Melanie H Cobb
- Department of Pharmacology UT Southwestern Medical Center Dallas TX USA
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13
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Morris SM. Arginine Metabolism Revisited. J Nutr 2016; 146:2579S-2586S. [PMID: 27934648 DOI: 10.3945/jn.115.226621] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/22/2016] [Accepted: 02/05/2016] [Indexed: 01/20/2023] Open
Abstract
Mammalian arginine metabolism is complex due to the expression of multiple enzymes that utilize arginine as substrate and to interactions or competition between specific enzymes involved in arginine metabolism. Moreover, cells may contain multiple intracellular arginine pools that are not equally accessible to all arginine metabolic enzymes, thus presenting additional challenges to more fully understanding arginine metabolism. At the whole-body level, arginine metabolism ultimately results in the production of a biochemically diverse range of products, including nitric oxide, urea, creatine, polyamines, proline, glutamate, agmatine, and homoarginine. Included in this group of compounds are the methylated arginines (e.g., asymmetric dimethylarginine), which are released upon degradation of proteins containing methylated arginine residues. Changes in arginine concentration also can regulate cellular metabolism and function via a variety of arginine sensors. Although much is known about arginine metabolism, elucidation of the physiologic or pathophysiologic roles for all of the pathways and their metabolites remains an active area of investigation, as exemplified by current findings highlighted in this review.
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Affiliation(s)
- Sidney M Morris
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
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14
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Zhou Y, Ren J, Song T, Peng J, Wei H. Methionine Regulates mTORC1 via the T1R1/T1R3-PLCβ-Ca 2+-ERK1/2 Signal Transduction Process in C2C12 Cells. Int J Mol Sci 2016; 17:ijms17101684. [PMID: 27727170 PMCID: PMC5085716 DOI: 10.3390/ijms17101684] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/20/2016] [Accepted: 09/27/2016] [Indexed: 12/13/2022] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) integrates amino acid (AA) availability to support protein synthesis and cell growth. Taste receptor type 1 member (T1R) is a G protein-coupled receptor that functions as a direct sensor of extracellular AA availability to regulate mTORC1 through Ca2+ stimulation and extracellular signal-regulated kinases 1 and 2 (ERK1/2) activation. However, the roles of specific AAs in T1R1/T1R3-regulated mTORC1 are poorly defined. In this study, T1R1 and T1R3 subunits were expressed in C2C12 myotubes, and l-AA sensing was accomplished by T1R1/T1R3 to activate mTORC1. In response to l-AAs, such as serine (Ser), arginine (Arg), threonine (Thr), alanine (Ala), methionine (Met), glutamine (Gln), and glycine (Gly), Met induced mTORC1 activation and promoted protein synthesis. Met also regulated mTORC1 via T1R1/T1R3-PLCβ-Ca2+-ERK1/2 signal transduction. Results revealed a new role for Met-regulated mTORC1 via an AA receptor. Further studies should be performed to determine the role of T1R1/T1R3 in mediating extracellular AA to regulate mTOR signaling and to reveal its mechanism.
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Affiliation(s)
- Yuanfei Zhou
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan 430070, Hubei, China.
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, Hubei, China.
| | - Jiao Ren
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan 430070, Hubei, China.
| | - Tongxing Song
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan 430070, Hubei, China.
| | - Jian Peng
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan 430070, Hubei, China.
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, Hubei, China.
| | - Hongkui Wei
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agriculture University, Wuhan 430070, Hubei, China.
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, Hubei, China.
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15
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On the selectivity of the Gαq inhibitor UBO-QIC: A comparison with the Gαi inhibitor pertussis toxin. Biochem Pharmacol 2016; 107:59-66. [PMID: 26954502 DOI: 10.1016/j.bcp.2016.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/03/2016] [Indexed: 01/14/2023]
Abstract
Gαq inhibitor UBO-QIC (FR900359) is becoming an important pharmacological tool, but its selectivity against other G proteins and their subunits, especially βγ, has not been well characterized. We examined UBO-QIC's effect on diverse signaling pathways mediated via various G protein-coupled receptors (GPCRs) and G protein subunits by comparison with known Gαi inhibitor pertussis toxin. As expected, UBO-QIC inhibited Gαq signaling in all assay systems examined. However, other non-Gαq-events, e.g. Gβγ-mediated intracellular calcium release and inositol phosphate production, following activation of Gi-coupled A1 adenosine and M2 muscarinic acetylcholine receptors, were also blocked by low concentrations of UBO-QIC, indicating that its effect is not limited to Gαq. Thus, UBO-QIC also inhibits Gβγ-mediated signaling similarly to pertussis toxin, although UBO-QIC does not affect Gαi-mediated inhibition or Gαs-mediated stimulation of adenylyl cyclase activity. However, the blockade by UBO-QIC of GPCR signaling, such as carbachol- or adenosine-mediated calcium or inositol phosphate increases, does not always indicate inhibition of Gαq-mediated events, as the βγ subunits released from Gi proteins following the activation of Gi-coupled receptors, e.g. M2 and A1Rs, may produce similar signaling events. Furthermore, UBO-QIC completely inhibited Akt signaling, but only partially blocked ERK1/2 activity stimulated by the Gq-coupled P2Y1R. Thus, we have revealed new aspects of the pharmacological interactions of UBO-QIC.
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