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Tokmakova A, Kim D, Guthrie B, Kim SK, Goddard WA, Liggett SB. Predicted structure and cell signaling of TAS2R14 reveal receptor hyper-flexibility for detecting diverse bitter tastes. iScience 2023; 26:106422. [PMID: 37096045 PMCID: PMC10121769 DOI: 10.1016/j.isci.2023.106422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 02/24/2023] [Accepted: 03/11/2023] [Indexed: 03/18/2023] Open
Abstract
The 25 human bitter taste receptors (TAS2Rs) are expressed on taste and extra-oral cells representing an integrated chemosensory system. The archetypal TAS2R14 is activated by > 150 topographically diverse agonists, raising the question of how this uncharacteristic accommodation is achieved for these GPCRs. We report the computationally derived structure of TAS2R14 with binding sites and energies for five highly diverse agonists. Remarkably, the binding pocket is the same for all five agonists. The energies derived from molecular dynamics are consistent with experiments determining signal transduction coefficients in live cells. TAS2R14 accommodates agonists through the breaking of a TMD3 H-bond instead of the prototypic strong salt bridge, a TMD1,2,7 interaction different from Class A GPCRs, and agonist-promoted TMD3 salt bridges for high affinity (which we confirmed by receptor mutagenesis). Thus, the broadly tuned TAS2Rs accommodate diverse agonists via a single (vs multiple) binding pocket through unique TM interactions for sensing disparate micro-environments.
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Affiliation(s)
- Alina Tokmakova
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - Donghwa Kim
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA
- Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA
| | - Brian Guthrie
- Cargill Global Food Research Center, Wayzata, MN 55391, USA
| | - Soo-Kyung Kim
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - William A. Goddard
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - Stephen B. Liggett
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA
- Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA
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Woo JAA, Castaño M, Kee TR, Lee J, Koziol-White CJ, An SS, Kim D, Kang DE, Liggett SB. A Par3/LIM Kinase/Cofilin Pathway Mediates Human Airway Smooth Muscle Relaxation by TAS2R14. Am J Respir Cell Mol Biol 2023; 68:417-429. [PMID: 36662576 PMCID: PMC10112429 DOI: 10.1165/rcmb.2022-0303oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/20/2023] [Indexed: 01/21/2023] Open
Abstract
TAS2Rs (bitter taste receptors) are GPCRs (G protein-coupled receptors) expressed on human airway smooth muscle (HASM) cells; when activated by receptor agonists they evoke marked airway relaxation. In both taste and HASM cells, TAS2Rs activate a canonical Gβγ-mediated stimulation of Ca2+ release from intracellular stores by activation of PLCβ (phospholipase Cβ). Alone, this [Ca2+]i signaling does not readily account for relaxation, particularly since bronchoconstrictive agonists acting at Gq-coupled receptors also increase [Ca2+]i. We established that TAS2R14 activation in HASM promotes relaxation through F-actin (filamentous actin) severing. This destabilization of actin was from agonist-promoted activation (dephosphorylation) of cofilin, which was pertussis toxin sensitive. Cofilin dephosphorylation was due to TAS2R-mediated deactivation of LIM domain kinase. The link between early receptor action and the distal cofilin dephosphorylation was found to be the polarity protein partitioning defective 3 (Par3), a known binding partner with PLCβ that inhibits LIM kinase. The physiologic relevance of this pathway was assessed using knock-downs of cofilin and Par3 in HASM cells and in human precision-cut lung slices. Relaxation by TAS2R14 agonists was ablated with knock-down of either protein as assessed by magnetic twisting cytometry in isolated cells or intact airways in the slices. Blocking [Ca2+]i release by TAS2R14 inhibited agonist-promoted cofilin dephosphorylation, confirming a role for [Ca2+]i in actin-modifying pathways. These results further elucidate the mechanistic basis of TAS2R-mediated HASM relaxation and point toward nodal points that may act as asthma or chronic obstructive pulmonary disease response modifiers or additional targets for novel bronchodilators.
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Affiliation(s)
- Jung-A A. Woo
- Department of Pathology, Case Western Reserve University, School of Medicine, Cleveland, Ohio
| | | | - Teresa R. Kee
- Department of Pathology, Case Western Reserve University, School of Medicine, Cleveland, Ohio
- Department of Molecular Medicine
| | - Jordan Lee
- Joint Graduate Program in Toxicology, Department of Pharmacology and Toxicology, Rutgers University Ernest Mario School of Pharmacy, Piscataway, New Jersey
| | - Cynthia J. Koziol-White
- Department of Pharmacology, Robert Wood Johnson Medical School, Piscataway, New Jersey; and
- Rutgers Institute for Translational Medicine and Science, New Brunswick, New Jersey
| | - Steven S. An
- Department of Pharmacology, Robert Wood Johnson Medical School, Piscataway, New Jersey; and
- Rutgers Institute for Translational Medicine and Science, New Brunswick, New Jersey
| | - Donghwa Kim
- Center for Personalized Medicine and Genomics
| | - David E. Kang
- Department of Pathology, Case Western Reserve University, School of Medicine, Cleveland, Ohio
| | - Stephen B. Liggett
- Department of Molecular Pharmacology and Physiology
- Center for Personalized Medicine and Genomics
- Department of Medicine, and
- Department of Medical Engineering, University of South Florida Morsani College of Medicine, Tampa, Florida
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3
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Identification and characterization of an atypical Gαs-biased β 2AR agonist that fails to evoke airway smooth muscle cell tachyphylaxis. Proc Natl Acad Sci U S A 2021; 118:2026668118. [PMID: 34857633 PMCID: PMC8670521 DOI: 10.1073/pnas.2026668118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 12/23/2022] Open
Abstract
We sought β2AR agonists for treating obstructive lung diseases such as asthma, in which this receptor relaxes airway smooth muscle (ASM) cells and opens airways. Agonists favoring Gs coupling (leads to airway relaxation) compared with activating β-arrestin (limits effectiveness due to receptor desensitization) were pursued in a 40-million-compound screening library. Of several agonists identified, one was apparently biased away from β-arrestin. Agonist–receptor–G protein modeling revealed different receptor interactions compared with other agonists. The favorable effects of the apparent biasing with this agonist were demonstrated in a physiologic system (ASM relaxation). These studies point to a different structural class of β-agonists that might be used to treat obstructive lung diseases without the adverse effects associated with tachyphylaxis. G protein–coupled receptors display multifunctional signaling, offering the potential for agonist structures to promote conformational selectivity for biased outputs. For β2-adrenergic receptors (β2AR), unbiased agonists stabilize conformation(s) that evoke coupling to Gαs (cyclic adenosine monophosphate [cAMP] production/human airway smooth muscle [HASM] cell relaxation) and β-arrestin engagement, the latter acting to quench Gαs signaling, contributing to receptor desensitization/tachyphylaxis. We screened a 40-million-compound scaffold ranking library, revealing unanticipated agonists with dihydroimidazolyl-butyl-cyclic urea scaffolds. The S-stereoisomer of compound C1 shows no detectable β-arrestin engagement/signaling by four methods. However, C1-S retained Gαs signaling—a divergence of the outputs favorable for treating asthma. Functional studies with two models confirmed the biasing: β2AR-mediated cAMP signaling underwent desensitization to the unbiased agonist albuterol but not to C1-S, and desensitization of HASM cell relaxation was observed with albuterol but not with C1-S. These HASM results indicate biologically pertinent biasing of C1-S, in the context of the relevant physiologic response, in the human cell type of interest. Thus, C1-S was apparently strongly biased away from β-arrestin, in contrast to albuterol and C5-S. C1-S structural modeling and simulations revealed binding differences compared with unbiased epinephrine at transmembrane (TM) segments 3,5,6,7 and ECL2. C1-S (R2 = cyclohexane) was repositioned in the pocket such that it lost a TM6 interaction and gained a TM7 interaction compared with the analogous unbiased C5-S (R2 = benzene group), which appears to contribute to C1-S biasing away from β-arrestin. Thus, an agnostic large chemical-space library identified agonists with receptor interactions that resulted in relevant signal splitting of β2AR actions favorable for treating obstructive lung disease.
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4
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Kim D, Castaño M, Lujan LK, Woo JA, Liggett SB. The short third intracellular loop and cytoplasmic tail of bitter taste receptors provide functionally relevant GRK phosphorylation sites in TAS2R14. J Biol Chem 2021; 296:100216. [PMID: 33465377 PMCID: PMC7949105 DOI: 10.1074/jbc.ra120.016056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/16/2020] [Accepted: 12/21/2020] [Indexed: 01/12/2023] Open
Abstract
For most G protein–coupled receptors, the third intracellular loop (IL3) and carboxy-terminal tail (CT) are sites for G protein–coupled receptor kinase (GRK)–mediated phosphorylation, leading to β-arrestin binding and agonist-specific desensitization. These regions of bitter taste receptors (TAS2Rs) are extremely short compared with the superfamily, and their function in desensitization is unknown. TAS2R14 expressed on human airway smooth muscle cells relax the cell, suggesting a novel target for bronchodilators. To assess IL3 and CT in agonist-promoted TAS2R14 desensitization (tachyphylaxis), we generated fusion proteins of both the WT sequence and Ala substituted for Ser/Thr in the IL3 and CT sequences. In vitro, activated GRK2 phosphorylated WT IL3 and WT CT proteins but not Ala-substituted forms. TAS2R14s with mutations in IL3 (IL-5A), CT (CT-5A), and in both regions (IL/CT-10A) were expressed in human embryonic kidney 293T cells. IL/CT-10A and CT-5A failed to undergo desensitization of the intracellular calcium response compared with WT, indicating that functional desensitization by GRK phosphorylation is at residues in the CT. Desensitization of TAS2R14 was blocked by GRK2 knockdown in human airway smooth muscle cells. Receptor:β-arrestin binding was absent in IL/CT-10A and CT-5A and reduced in IL-5A, indicating a role for IL3 phosphorylation in the β-arrestin interaction for this function. Agonist-promoted internalization of IL-5A and CT-5A receptors was impaired, and they failed to colocalize with early endosomes. Thus, agonist-promoted functional desensitization of TAS2R14 occurs by GRK phosphorylation of CT residues and β-arrestin binding. However, β-arrestin function in the internalization and trafficking of the receptor also requires GRK phosphorylation of IL3 residues.
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Affiliation(s)
- Donghwa Kim
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Maria Castaño
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Lauren K Lujan
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Jung A Woo
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Stephen B Liggett
- Departments of Medicine and Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA.
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Medapati MR, Bhagirath AY, Singh N, Chelikani P. Pharmacology of T2R Mediated Host-Microbe Interactions. Handb Exp Pharmacol 2021; 275:177-202. [PMID: 33580389 DOI: 10.1007/164_2021_435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bitter taste receptors (T2Rs) belong to the G protein-coupled receptor superfamily. Humans express 25 T2Rs that are known to detect several bitter compounds including bacterial quorum sensing molecules (QSM). Primarily found to be key receptors for bitter sensation T2Rs are known to play an important role in mediating innate immune responses in oral and extraoral tissues. Several studies have led to identification of Gram-negative and Gram-positive bacterial QSMs as agonists for T2Rs in airway epithelial cells and immune cells. However, the pharmacological characterization for many of the QSM-T2R interactions remains poorly defined. In this chapter, we discuss the extraoral roles including localization of T2Rs in extracellular vesicles, molecular pharmacology of QSM-T2R interactions, role of T2Rs in mediating innate immune responses, and some of the challenges in understanding T2R pharmacology.
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Affiliation(s)
- Manoj Reddy Medapati
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Anjali Y Bhagirath
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada.
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada.
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Schroer AB, Branyan KW, Gross JD, Chantler PD, Kimple AJ, Vandenbeuch A, Siderovski DP. The stability of tastant detection by mouse lingual chemosensory tissue requires Regulator of G protein Signaling-21 (RGS21). Chem Senses 2021; 46:6414340. [PMID: 34718440 DOI: 10.1093/chemse/bjab048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The T1R and T2R families of G protein-coupled receptors (GPCRs) initiate tastant perception by signaling via guanine nucleotide exchange and hydrolysis performed by associated heterotrimeric G proteins (Gαβγ). Heterotrimeric G protein signal termination is sped up by Gα-directed GTPase-accelerating proteins (GAPs) known as the Regulators of G protein Signaling (RGS proteins). Of this family, RGS21 is highly expressed in lingual epithelial cells and we have shown it acting in vitro to decrease the potency of bitterants on cultured cells. However, constitutive RGS21 loss in mice reduces organismal response to GPCR-mediated tastants-opposite to expectations arising from observed in vitro activity of RGS21 as a GAP and inhibitor of T2R signaling. Here, we show reduced quinine aversion and reduced sucrose preference by mice lacking RGS21 does not result from post-ingestive effects, as taste-salient brief-access tests confirm the reduced bitterant aversion and reduced sweetener preference seen using two-bottle choice testing. Eliminating Rgs21 expression after chemosensory system development, via tamoxifen-induced Cre recombination in eight week-old mice, led to a reduction in quinine aversive behavior that advanced over time, suggesting that RGS21 functions as a negative regulator to sustain stable bitter tastant reception. Consistent with this notion, we observed downregulation of multiple T2R proteins in the lingual tissue of Rgs21-deficient mice. Reduced tastant-mediated responses exhibited by mice lacking Rgs21 expression either since birth or in adulthood has highlighted the potential requirement for a GPCR GAP to maintain the full character of tastant signaling, likely at the level of mitigating receptor downregulation.
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Affiliation(s)
- Adam B Schroer
- Department of Neuroscience, West Virginia University School of Medicine, 64 Medical Center Drive, Morgantown, WV 26506, USA
| | - Kayla W Branyan
- Division of Exercise Physiology, West Virginia University School of Medicine, 64 Medical Center Drive, Morgantown, WV 26506, USA
| | - Joshua D Gross
- Department of Cell Biology, Duke University Medical Center, 307 Research Drive, Durham, NC 27710, USA
| | - Paul D Chantler
- Division of Exercise Physiology, West Virginia University School of Medicine, 64 Medical Center Drive, Morgantown, WV 26506, USA
| | - Adam J Kimple
- Department of Otolaryngology and Marsico Lung Institute, UNC School of Medicine , 170 Manning Drive, Chapel Hill, NC 27599-7070, USA
| | - Aurelie Vandenbeuch
- Department of Otolaryngology, University of Colorado-Denver, Anschutz Medical Campus, 12700 E. 19th Avenue, Aurora, CO 80045, USA
| | - David P Siderovski
- Department of Pharmacology & Neuroscience, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA
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7
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Grau-Bové C, Miguéns-Gómez A, González-Quilen C, Fernández-López JA, Remesar X, Torres-Fuentes C, Ávila-Román J, Rodríguez-Gallego E, Beltrán-Debón R, Blay MT, Terra X, Ardévol A, Pinent M. Modulation of Food Intake by Differential TAS2R Stimulation in Rat. Nutrients 2020; 12:E3784. [PMID: 33321802 PMCID: PMC7762996 DOI: 10.3390/nu12123784] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022] Open
Abstract
Metabolic surgery modulates the enterohormone profile, which leads, among other effects, to changes in food intake. Bitter taste receptors (TAS2Rs) have been identified in the gastrointestinal tract and specific stimulation of these has been linked to the control of ghrelin secretion. We hypothesize that optimal stimulation of TAS2Rs could help to modulate enteroendocrine secretions and thus regulate food intake. To determine this, we have assayed the response to specific agonists for hTAS2R5, hTAS2R14 and hTAS2R39 on enteroendocrine secretions from intestinal segments and food intake in rats. We found that hTAS2R5 agonists stimulate glucagon-like peptide 1 (GLP-1) and cholecystokinin (CCK), and reduce food intake. hTAS2R14 agonists induce GLP1, while hTASR39 agonists tend to increase peptide YY (PYY) but fail to reduce food intake. The effect of simultaneously activating several receptors is heterogeneous depending on the relative affinity of the agonists for each receptor. Although detailed mechanisms are not clear, bitter compounds can stimulate differentially enteroendocrine secretions that modulate food intake in rats.
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Grants
- AGL2017-83477-R Ministerio de Economía, Industria y Competitividad, Gobierno de España
- R2B2018/03 Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya
- Martí Franqués Universitat Rovira i Virgili
- FI Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya
- Beatriu de Pinós Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya
- Serra Hunter Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya
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Affiliation(s)
- Carme Grau-Bové
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - Alba Miguéns-Gómez
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - Carlos González-Quilen
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - José-Antonio Fernández-López
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; (J.-A.F.-L.); (X.R.)
- CIBER Obesity and Nutrition, Institute of Health Carlos III, Av. Diagonal 643, 08028 Barcelona, Spain
| | - Xavier Remesar
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; (J.-A.F.-L.); (X.R.)
- CIBER Obesity and Nutrition, Institute of Health Carlos III, Av. Diagonal 643, 08028 Barcelona, Spain
| | - Cristina Torres-Fuentes
- Nutrigenomics Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.T.-F.); (J.Á.-R.)
| | - Javier Ávila-Román
- Nutrigenomics Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.T.-F.); (J.Á.-R.)
| | - Esther Rodríguez-Gallego
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - Raúl Beltrán-Debón
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - M Teresa Blay
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - Ximena Terra
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - Anna Ardévol
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
| | - Montserrat Pinent
- MoBioFood Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; (C.G.-B.); (A.M.-G.); (C.G.-Q.); (E.R.-G.); (R.B.-D.); (M.T.B.); (X.T.); (M.P.)
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8
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Kim D, An SS, Lam H, Leahy JW, Liggett SB. Identification and Characterization of Novel Bronchodilator Agonists Acting at Human Airway Smooth Muscle Cell TAS2R5. ACS Pharmacol Transl Sci 2020; 3:1069-1075. [PMID: 33344890 DOI: 10.1021/acsptsci.0c00127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Indexed: 01/25/2023]
Abstract
Bitter taste receptors (TAS2Rs) are recognized as being expressed on multiple cell types and organs, including human airway smooth muscle (HASM) cells, where agonists promote significant relaxation to constrictive stimuli. Thus, the HASM TAS2Rs have been targeted as novel bronchodilators for the treatment of asthma and other obstructive lung diseases. The TAS2R5 subtype, a dominant receptor on HASM, has few known agonists, all with reported low potency and efficacy. We screened multiple compounds by measuring [Ca2+]i release in HASM (a consequence of receptor-G protein coupling) to establish structure-activity relationships and arrive at a potent agonist for TAS2R5. HASM physiological studies using magnetic twisting cytometry confirmed the relaxation effects of lead compounds. 1,10-Phenanthroline-5,6-dione had the greatest potency (EC50 ≈ 120 nM), amounting to a >1000-fold improvement over the other compounds, and displayed maximal efficacy. These studies revealed critical structural requirements for favorable potencies and efficacies for a potential first-in-class bronchodilator targeting TAS2R5 of the airway.
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Affiliation(s)
- Donghwa Kim
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida 33602, United States
| | - Steven S An
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, and Institute for Translational Medicine & Science, The State University of New Jersey, Piscataway, New Jersey 08901, United States
| | - Hong Lam
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, and Institute for Translational Medicine & Science, The State University of New Jersey, Piscataway, New Jersey 08901, United States
| | - James W Leahy
- Department of Chemistry and the Florida Center of Excellence for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States.,Department of Molecular Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida 33613, United States
| | - Stephen B Liggett
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida 33602, United States.,Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida 33620, United States
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9
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Conaway S, Nayak AP, Deshpande DA. Therapeutic potential and challenges of bitter taste receptors on lung cells. Curr Opin Pharmacol 2020; 51:43-49. [PMID: 32810767 PMCID: PMC7530014 DOI: 10.1016/j.coph.2020.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/27/2020] [Accepted: 07/09/2020] [Indexed: 11/26/2022]
Abstract
Airway smooth muscle (ASM) hyperresponsiveness and airway remodeling are pathological drivers of disease progression and mortality in asthma. Importantly, approximately 50% of affected individuals are unable to reliably manage disease symptoms using the current standard of care. Recently, T2Rs have been identified as a novel class of G protein-coupled receptors expressed in the airway that on activation can induce ASM relaxation and reduction in airway tone. Further, agonists of T2Rs may also remedy airway remodeling, which has been difficult to manage with currently available medications. In this review, we will discuss the recent developments in T2R biology and their role in cellular physiology (particularly ASM) and expand on the therapeutic potential of T2R agonists in treatment of asthma.
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Affiliation(s)
- Stanley Conaway
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Ajay P Nayak
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Deepak A Deshpande
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA 19107, United States.
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