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Miller ZA, Mueller A, Kim T, Jolivert JF, Ma RZ, Muthuswami S, Park A, McMahon DB, Nead KT, Carey RM, Lee RJ. Lidocaine induces apoptosis in head and neck squamous cell carcinoma through activation of bitter taste receptor T2R14. Cell Rep 2023; 42:113437. [PMID: 37995679 PMCID: PMC10842818 DOI: 10.1016/j.celrep.2023.113437] [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: 04/14/2023] [Revised: 09/22/2023] [Accepted: 10/29/2023] [Indexed: 11/25/2023] Open
Abstract
Head and neck squamous cell carcinomas (HNSCCs) have high mortality and significant treatment-related morbidity. It is vital to discover effective, minimally invasive therapies that improve survival and quality of life. Bitter taste receptors (T2Rs) are expressed in HNSCCs, and T2R activation can induce apoptosis. Lidocaine is a local anesthetic that also activates bitter taste receptor 14 (T2R14). Lidocaine has some anti-cancer effects, but the mechanisms are unclear. Here, we find that lidocaine causes intracellular Ca2+ mobilization through activation of T2R14 in HNSCC cells. T2R14 activation with lidocaine depolarizes mitochondria, inhibits proliferation, and induces apoptosis. Concomitant with mitochondrial Ca2+ influx, ROS production causes T2R14-dependent accumulation of poly-ubiquitinated proteins, suggesting that proteasome inhibition contributes to T2R14-induced apoptosis. Lidocaine may have therapeutic potential in HNSCCs as a topical gel or intratumor injection. In addition, we find that HPV-associated (HPV+) HNSCCs are associated with increased TAS2R14 expression. Lidocaine treatment may benefit these patients, warranting future clinical studies.
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Affiliation(s)
- Zoey A Miller
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Arielle Mueller
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - TaeBeom Kim
- Department of Epidemiology, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jennifer F Jolivert
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ray Z Ma
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sahil Muthuswami
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - April Park
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Derek B McMahon
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Kevin T Nead
- Department of Epidemiology, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ryan M Carey
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - Robert J Lee
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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Ikhmais BA, Hammad AM, Abusara OH, Hamadneh L, Abumansour H, Abdallah QM, Ibrahim AIM, Elsalem L, Awad M, Alshehada R. Investigating Carvedilol's Repurposing for the Treatment of Non-Small Cell Lung Cancer via Aldehyde Dehydrogenase Activity Modulation in the Presence of β-Adrenergic Agonists. Curr Issues Mol Biol 2023; 45:7996-8012. [PMID: 37886948 PMCID: PMC10605277 DOI: 10.3390/cimb45100505] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
Repurposing existing drugs appears to be a potential solution for addressing the challenges in the treatment of non-small cell lung cancer (NSCLC). β-adrenoceptor antagonist drugs (β-blockers) have tumor-inhibiting effects, making them promising candidates for potential NSCLC treatment. This study investigates the anticancer potential of a subset of β-blockers in NSCLC cell lines; A549 and H1299. Additionally, it investigates the underlying mechanism behind β-blockers' anticancer effect by influencing a potential novel target named aldehyde dehydrogenase (ALDH). The MTT assay assessed β-blockers' cytotoxicity on both cell lines, while Western blot and NADH fluorescence assays evaluated their influence on ALDH protein expression and activity. Carvedilol (CAR) was the most effective blocker in reducing cell survival of A549 and H1299 with IC50 of 18 µM and 13.7 µM, respectively. Significantly, CAR led to a 50% reduction in ALDH expression and 80% decrease in ALDH activity in A549 cells, especially when combined with β-agonists, in comparison to the control. This effect might be attributed to β-agonist blockade or an alternative pathway. This novel finding adds to our understanding of CAR's multifaceted anticancer properties, implying that combining CAR with β-agonists could be a useful strategy for lung cancer treatment.
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Affiliation(s)
- Balqis A. Ikhmais
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
| | - Alaa M. Hammad
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
| | - Osama H. Abusara
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
| | - Lama Hamadneh
- Department of Basic Medical Sciences, Faculty of Medicine, Al-Balqa Applied University, P.O. Box 206, Al-Salt 19117, Jordan;
| | - Hamza Abumansour
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
| | - Qasem M. Abdallah
- Department of Pharmacology and Biomedical Sciences, Faculty of Pharmacy and Medical Sciences, University of Petra, P.O. Box 961343, Amman 11196, Jordan;
| | - Ali I. M. Ibrahim
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
| | - Lina Elsalem
- Department of Pharmacology, Faculty of Medicine, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan;
| | - Mariam Awad
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
| | - Rahaf Alshehada
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman 11733, Jordan; (A.M.H.); (O.H.A.); (H.A.); (A.I.M.I.); (M.A.); (R.A.)
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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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Cilia Stimulatory and Antibacterial Activities of T2R Bitter Taste Receptor Agonist Diphenhydramine: Insights into Repurposing Bitter Drugs for Nasal Infections. Pharmaceuticals (Basel) 2022; 15:ph15040452. [PMID: 35455449 PMCID: PMC9025516 DOI: 10.3390/ph15040452] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 03/29/2022] [Accepted: 04/02/2022] [Indexed: 02/06/2023] Open
Abstract
T2R bitter taste receptors in airway motile cilia increase ciliary beat frequency (CBF) and nitric oxide (NO) production. Polymorphisms in some T2Rs are linked to disease outcomes in chronic rhinosinusitis (CRS) and cystic fibrosis (CF). We examined the expression of cilia T2Rs during the differentiation of human nasal epithelial cells grown at air–liquid interface (ALI). The T2R expression increased with differentiation but did not vary between CF and non-CF cultures. Treatment with Pseudomonas aeruginosa flagellin decreased the expression of diphenhydramine-responsive T2R14 and 40, among others. Diphenhydramine increased both NO production, measured by fluorescent dye DAF-FM, and CBF, measured via high-speed imaging. Increases in CBF were disrupted after flagellin treatment. Diphenhydramine impaired the growth of lab and clinical strains of P. aeruginosa, a major pathogen in CF and CF-related CRS. Diphenhydramine impaired biofilm formation of P. aeruginosa, measured via crystal violet staining, as well as the surface attachment of P. aeruginosa to CF airway epithelial cells, measured using colony-forming unit counting. Because the T2R agonist diphenhydramine increases NO production and CBF while also decreasing bacterial growth and biofilm production, diphenhydramine-derived compounds may have potential clinical usefulness in CF-related CRS as a topical therapy. However, utilizing T2R agonists as therapeutics within the context of P. aeruginosa infection may require co-treatment with anti-inflammatories to enhance T2R expression.
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6
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The Effect of Beta Adrenoreceptor Blockers on Viability and Cell Colony Formation of Non-Small Cell Lung Cancer Cell Lines A549 and H1299. Molecules 2022; 27:molecules27061938. [PMID: 35335303 PMCID: PMC8950283 DOI: 10.3390/molecules27061938] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 03/11/2022] [Accepted: 03/15/2022] [Indexed: 12/24/2022] Open
Abstract
Beta adrenoblockers are a large class of drugs used to treat cardiovascular diseases, migraines, glaucoma and hyperthyroidism. Over the last couple of decades, the anticancer effects of these compounds have been extensively studied. However, the exact mechanism is still not known, and more detailed studies are required. The aim of our study was to evaluate the anticancer activity of beta adrenoblockers in non-small cell lung cancer cell lines A549 and H1299. In order to find the relationship with their selectivity to beta adrenoreceptors, selective (atenolol, betaxolol, esmolol, metoprolol) and non-selective (pindolol, propranolol and timolol) beta blockers were tested. The effect on cell viability was evaluated by MTT assay, and the activity on cell ability to form colonies was tested by clonogenic assay. The type of cell death was evaluated by cell double staining with Hoechst 33342 and Propidium iodide. The most active adrenoblockers against both tested cancer cell lines were propranolol and betaxolol. They completely inhibited lung cancer cell colony formation at 90% of the EC50 (half-maximal effective concentration) value. Most tested compounds induced cell death through apoptosis and necrosis. There was no correlation established between beta adrenoblocker anticancer activity and their selectivity to beta adrenoreceptors.
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McMahon DB, Kuek LE, Johnson ME, Johnson PO, Horn RL, Carey RM, Adappa ND, Palmer JN, Lee RJ. The bitter end: T2R bitter receptor agonists elevate nuclear calcium and induce apoptosis in non-ciliated airway epithelial cells. Cell Calcium 2022; 101:102499. [PMID: 34839223 PMCID: PMC8752513 DOI: 10.1016/j.ceca.2021.102499] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/21/2021] [Accepted: 10/31/2021] [Indexed: 01/03/2023]
Abstract
Bitter taste receptors (T2Rs) localize to airway motile cilia and initiate innate immune responses in retaliation to bacterial quorum sensing molecules. Activation of cilia T2Rs leads to calcium-driven NO production that increases cilia beating and directly kills bacteria. Several diseases, including chronic rhinosinusitis, COPD, and cystic fibrosis, are characterized by loss of motile cilia and/or squamous metaplasia. To understand T2R function within the altered landscape of airway disease, we studied T2Rs in non-ciliated airway cell lines and primary cells. Several T2Rs localize to the nucleus in de-differentiated cells that typically localize to cilia in differentiated cells. As cilia and nuclear import utilize shared proteins, some T2Rs may target to the nucleus in the absence of motile cilia. T2R agonists selectively elevated nuclear and mitochondrial calcium through a G-protein-coupled receptor phospholipase C mechanism. Additionally, T2R agonists decreased nuclear cAMP, increased nitric oxide, and increased cGMP, consistent with T2R signaling. Furthermore, exposure to T2R agonists led to nuclear calcium-induced mitochondrial depolarization and caspase activation. T2R agonists induced apoptosis in primary bronchial and nasal cells differentiated at air-liquid interface but then induced to a squamous phenotype by apical submersion. Air-exposed well-differentiated cells did not die. This may be a last-resort defense against bacterial infection. However, it may also increase susceptibility of de-differentiated or remodeled epithelia to damage by bacterial metabolites. Moreover, the T2R-activated apoptosis pathway occurs in airway cancer cells. T2Rs may thus contribute to microbiome-tumor cell crosstalk in airway cancers. Targeting T2Rs may be useful for activating cancer cell apoptosis while sparing surrounding tissue.
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Affiliation(s)
- Derek B. McMahon
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA,Correspondence: Derek B. McMahon, PhD or Robert J. Lee, PhD, Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA USA, 215-573-9766, (D.B.M.) or (R.J.L)
| | - Li Eon Kuek
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Madeline E. Johnson
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Paige O. Johnson
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Rachel L.J. Horn
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Ryan M. Carey
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Nithin D. Adappa
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - James N. Palmer
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Robert J. Lee
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA,Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA,Correspondence: Derek B. McMahon, PhD or Robert J. Lee, PhD, Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA USA, 215-573-9766, (D.B.M.) or (R.J.L)
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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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Sung WW, Tu JH, Yu JS, Ulfa MZ, Chang JH, Cheng HL. Bacillus amyloliquefaciens exopolysaccharide preparation induces glucagon-like peptide 1 secretion through the activation of bitter taste receptors. Int J Biol Macromol 2021; 185:562-571. [PMID: 34216658 DOI: 10.1016/j.ijbiomac.2021.06.187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 12/23/2022]
Abstract
The exopolysaccharide preparation of Bacillus amyloliquefaciens amy-1 (EPS) regulates glycemic levels and promotes glucagon-like peptide 1 (GLP-1) secretion in vivo and in vitro. This study aimed to identify the molecular mechanism underlying EPS-induced GLP-1 secretion. HEK293T cells stably expressing human Gα-gustducin were used as a heterologous system for expressing the genes of human bitter taste receptor (T2R) 10, 14, 30, 38 (PAV), 38 (AVI), 43, and 46, which were expressed as recombinant proteins with an N-terminal tag composed of a Lucy peptide and a human somatostatin receptor subtype 3 fragment for membrane targeting and a C-terminal red fluorescent protein for expression monitoring. EPS induced a dose-dependent calcium response from the human NCI-H716 enteroendocrine cell line revealed by fluorescent calcium imaging, but inhibitors of the G protein-coupled receptor pathway suppressed the response. EPS activated heterologously expressed T2R14 and T2R38 (PAV). shRNAs of T2R14 effectively inhibited EPS-induced calcium response and GLP-1 secretion in NCI-H716 cells, suggesting the involvement of T2R14 in these effects. The involvement of T2R38 was not characterized because NCI-H716 cells express T2R38 (AVI). In conclusion, the activation of T2Rs mediates EPS-induced GLP-1 secretion from enteroendocrine cells, and T2R14 is a critical target activated by EPS in these cells.
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Affiliation(s)
- Wei-Wen Sung
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, No. 1, Shuehfu Rd., Neipu Township, Pingtung 912301, Taiwan
| | - Jing-Hong Tu
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, No. 1, Shuehfu Rd., Neipu Township, Pingtung 912301, Taiwan
| | - Jyun-Sian Yu
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, No. 1, Shuehfu Rd., Neipu Township, Pingtung 912301, Taiwan
| | - Marisa Zakiya Ulfa
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, No. 1, Shuehfu Rd., Neipu Township, Pingtung 912301, Taiwan; Department of Agroindustrial Biotechnology, Brawijaya University, Jalan Veteran, Malang 65145, Indonesia
| | - Jia-Hong Chang
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, No. 1, Shuehfu Rd., Neipu Township, Pingtung 912301, Taiwan
| | - Hsueh-Ling Cheng
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, No. 1, Shuehfu Rd., Neipu Township, Pingtung 912301, Taiwan.
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10
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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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11
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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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12
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Duroux R, Mandeau A, Guiraudie-Capraz G, Quesnel Y, Loing E. A Rose Extract Protects the Skin against Stress Mediators: A Potential Role of Olfactory Receptors. Molecules 2020; 25:molecules25204743. [PMID: 33081083 PMCID: PMC7587601 DOI: 10.3390/molecules25204743] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/12/2022] Open
Abstract
Olfactory receptors (ORs) are expressed and active in various human tissues, including the skin. Although the sense of smell plays an important physiological role in the regulation of mood and stress, a link between olfactive compounds, ORs, and skin stress has yet to be established. This study aims to investigate the role of newly identified skin ORs and agonists in the modulation of skin stress. Screening for odorant molecules was done with cAMP functional assay to identify OR agonists. RT-qPCR and immunofluorescence microscopy were conducted to identify and quantify ORs in epidermal keratinocytes (NHEKs) and human skin explants, as well as to evaluate specific markers (G6PDH, loricrin, and γH2AX) of stress-induced skin alterations. A randomized double-blinded, split-face clinical study was performed on a panel of stressed women to measure the benefits of OR agonist treatment for skin. Three new ORs (OR10A6, OR2AG2, and OR11H4) were identified in skin. A specific Rose extract and its major constituent (phenylethyl alcohol) were found to activate these ORs. The extract composition was revealed by both GC/FID and GC/MS analyses simultaneously and showed the presence of 34 volatiles molecules. Moreover, epinephrine induces a skin stress response characterized by increased expression of G6PD, loricrin, and γH2AX biomarkers, and a decrease of OR expression. These effects were prevented in the presence of rose extract and its benefits were confirmed clinically by a decrease in the appearance of under-eye dark circles. Altogether, our findings suggest that ORs may represent a new, promising way to treat stress-associated skin disorders.
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Affiliation(s)
- Romain Duroux
- Department of Research and Development, International Flavors and Fragrances-Lucas Meyer Cosmetics, 31036 Toulouse CEDEX, France;
- Correspondence:
| | - Anne Mandeau
- Department of Research and Development, International Flavors and Fragrances-Lucas Meyer Cosmetics, 31036 Toulouse CEDEX, France;
| | - Gaelle Guiraudie-Capraz
- Institute of Neurophysiopathology, CNRS, Aix-Marseille University, UMR 7051, CEDEX 15, F-13344 Marseille, France;
| | | | - Estelle Loing
- Department of Research and Development, International Flavors and Fragrances-Lucas Meyer Cosmetics, Quebec, QC G1V 4M6, Canada;
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13
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Bloxham CJ, Foster SR, Thomas WG. A Bitter Taste in Your Heart. Front Physiol 2020; 11:431. [PMID: 32457649 PMCID: PMC7225360 DOI: 10.3389/fphys.2020.00431] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 04/08/2020] [Indexed: 12/11/2022] Open
Abstract
The human genome contains ∼29 bitter taste receptors (T2Rs), which are responsible for detecting thousands of bitter ligands, including toxic and aversive compounds. This sentinel function varies between individuals and is underpinned by naturally occurring T2R polymorphisms, which have also been associated with disease. Recent studies have reported the expression of T2Rs and their downstream signaling components within non-gustatory tissues, including the heart. Though the precise role of T2Rs in the heart remains unclear, evidence points toward a role in cardiac contractility and overall vascular tone. In this review, we summarize the extra-oral expression of T2Rs, focusing on evidence for expression in heart; we speculate on the range of potential ligands that may activate them; we define the possible signaling pathways they activate; and we argue that their discovery in heart predicts an, as yet, unappreciated cardiac physiology.
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Affiliation(s)
- Conor J Bloxham
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Simon R Foster
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Walter G Thomas
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
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14
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Woo JA, Castaño M, Goss A, Kim D, Lewandowski EM, Chen Y, Liggett SB. Differential long-term regulation of TAS2R14 by structurally distinct agonists. FASEB J 2019; 33:12213-12225. [PMID: 31430434 DOI: 10.1096/fj.201802627rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Bitter taste receptor-14 (TAS2R14) is a GPCR also expressed on human airway smooth muscle cells, which signals to intracellular [Ca2+], resulting in relaxation of the airway, and is a novel target for bronchodilators. Here, we examine long-term, agonist-promoted down-regulation of TAS2R14 expression because tachyphylaxis would be an undesirable therapeutic characteristic. Five TAS2R structurally distinct full agonists were studied to ascertain biasing away from down-regulation. Agonist exposure for 18 h caused minimal desensitization by diphenhydramine (DPD) compared with ∼50% desensitization with all other agonists. Agonists evoked β-arrestin recruitment to TAS2R14, which was not seen with a phosphoacceptor-deficient mutant, TAS2R14-10A. All agonists except for DPD also caused subsequent TAS2R14 internalization and trafficking via early and late endosomes to down-regulation. TAS2R14-10A failed to undergo these events with any agonist. Molecular docking showed that DPD has specific interactions deep within a binding pocket that are not observed with the other agonists, which may lock the receptor in a conformation that does not internalize and therefore does not undergo down-regulation. Thus, TAS2R14 is subject to β-arrestin-mediated internalization and subsequent down-regulation with chronic exposure to most agonists. However, by manipulating the agonist structure, biasing toward G-protein coupling but away from long-term down-regulation can be achieved.-Woo, J. A., Castaño, M., Goss, A., Kim, D., Lewandowski, E. M., Chen, Y., Liggett, S. B. Differential long-term regulation of TAS2R14 by structurally distinct agonists.
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Affiliation(s)
- Jung A Woo
- Department of Molecular Pharmacology and Physiology, 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
| | - Ashley Goss
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Donghwa Kim
- Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Eric M Lewandowski
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Stephen B Liggett
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA.,Department of Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
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15
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Taher S, Borja Y, Cabanela L, Costers VJ, Carson-Marino M, Bailes JC, Dhar B, Beckworth MT, Rabaglino MB, Post Uiterweer ED, Conrad KP. Cholecystokinin, gastrin, cholecystokinin/gastrin receptors, and bitter taste receptor TAS2R14: trophoblast expression and signaling. Am J Physiol Regul Integr Comp Physiol 2019; 316:R628-R639. [PMID: 30892908 PMCID: PMC6589605 DOI: 10.1152/ajpregu.00153.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 02/07/2023]
Abstract
We investigated expression of cholecystokinin (CCK) in humans and mice, and the bitter taste receptor TAS2R14 in the human placenta. Because CCK and gastrin activate the CCKBR receptor, we also explored placental gastrin expression. Finally, we investigated calcium signaling by CCK and TAS2R14. By RT-PCR, we found CCK/Cck and GAST/Gast mRNA expression in both normal human and mouse placentas, as well as in human trophoblast cell lines (TCL). Although both Cckar and -br mRNA were expressed in the mouse placenta, only CCKBR mRNA was detected in the human placenta and TCL. mRNA expression for TAS2R14 was also observed in the human placenta and TCL. Using immunohistochemistry, CCK protein was localized to the syncytiotrophoblast (ST) and extravillous trophoblast (EVT) in the human term placenta, and to trophoblast glycogen cells in mouse and human placentas. Gastrin and TAS2R14 proteins were also observed in ST and EVT of the human placenta. Both sulfated and nonsulfated CCK elicited a comparable rise in intracellular calcium in TCL, consistent with CCKBR expression. Three TAS2R14 agonists, flufenamic acid, chlorhexidine, and diphenhydramine, also evoked rises in intracellular calcium in TCL. These results establish CCK, gastrin, and their receptor(s) in both human and mouse placentas, and TAS2R14 in the human placenta. Both CCK and TAS2R14 agonists increased intracellular calcium in human TCL. Although the roles of these ligands and receptors, and their potential cross talk in normal and pathological placentas, are currently unknown, this study opens new avenues for placental research.
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MESH Headings
- Animals
- Calcium Signaling
- Cell Line
- Cholecystokinin/genetics
- Cholecystokinin/metabolism
- Cholecystokinin/pharmacology
- Female
- Gastrins/genetics
- Gastrins/metabolism
- Gene Expression Regulation, Developmental
- Humans
- Ligands
- Mice
- Mice, Inbred C57BL
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Cholecystokinin B/genetics
- Receptor, Cholecystokinin B/metabolism
- Receptors, Cholecystokinin/agonists
- Receptors, Cholecystokinin/genetics
- Receptors, Cholecystokinin/metabolism
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- Trophoblasts/drug effects
- Trophoblasts/metabolism
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Affiliation(s)
- Shèdy Taher
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Yamilette Borja
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Lucía Cabanela
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Vincent J Costers
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Morgan Carson-Marino
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Julie C Bailes
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Biswadeep Dhar
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Mark T Beckworth
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
| | - Maria B Rabaglino
- Instituto de Investigaciones en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Técnicas, Pabellón de Biología Celular, Córdoba , Argentina
| | - Emiel D Post Uiterweer
- Department of Obstetrics and Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht , Utrecht , The Netherlands
| | - Kirk P Conrad
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, and D. H. Barron Reproductive and Perinatal Biology Research Program, Gainesville, Florida
- Department of Obstetrics and Gynecology, University of Florida College of Medicine , Gainesville, Florida
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16
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Freund JR, Mansfield CJ, Doghramji LJ, Adappa ND, Palmer JN, Kennedy DW, Reed DR, Jiang P, Lee RJ. Activation of airway epithelial bitter taste receptors by Pseudomonas aeruginosa quinolones modulates calcium, cyclic-AMP, and nitric oxide signaling. J Biol Chem 2018; 293:9824-9840. [PMID: 29748385 DOI: 10.1074/jbc.ra117.001005] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 04/17/2018] [Indexed: 12/12/2022] Open
Abstract
Bitter taste receptors (taste family 2 bitter receptor proteins; T2Rs), discovered in many tissues outside the tongue, have recently become potential therapeutic targets. We have shown previously that airway epithelial cells express several T2Rs that activate innate immune responses that may be important for treatment of airway diseases such as chronic rhinosinusitis. It is imperative to more clearly understand what compounds activate airway T2Rs as well as their full range of functions. T2R isoforms in airway motile cilia (T2R4, -14, -16, and -38) produce bactericidal levels of nitric oxide (NO) that also increase ciliary beating, promoting clearance of mucus and trapped pathogens. Bacterial quorum-sensing acyl-homoserine lactones activate T2Rs and stimulate these responses in primary airway cells. Quinolones are another type of quorum-sensing molecule used by Pseudomonas aeruginosa To elucidate whether bacterial quinolones activate airway T2Rs, we analyzed calcium, cAMP, and NO dynamics using a combination of fluorescent indicator dyes and FRET-based protein biosensors. T2R-transfected HEK293T cells, several lung epithelial cell lines, and primary sinonasal cells grown and differentiated at the air-liquid interface were tested with 2-heptyl-3-hydroxy-4-quinolone (known as Pseudomonas quinolone signal; PQS), 2,4-dihydroxyquinolone, and 4-hydroxy-2-heptylquinolone (HHQ). In HEK293T cells, PQS activated T2R4, -16, and -38, whereas HHQ activated T2R14. 2,4-Dihydroxyquinolone had no effect. PQS and HHQ increased calcium and decreased both baseline and stimulated cAMP levels in cultured and primary airway cells. In primary cells, PQS and HHQ activated levels of NO synthesis previously shown to be bactericidal. This study suggests that airway T2R-mediated immune responses are activated by bacterial quinolones as well as acyl-homoserine lactones.
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Affiliation(s)
- Jenna R Freund
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | | | | | - Nithin D Adappa
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | - James N Palmer
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | - David W Kennedy
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | - Danielle R Reed
- the Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Peihua Jiang
- the Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Robert J Lee
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and .,Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104 and
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17
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Kim D, Cho S, Woo JA, Liggett SB. A CREB-mediated increase in miRNA let-7f during prolonged β-agonist exposure: a novel mechanism of β 2-adrenergic receptor down-regulation in airway smooth muscle. FASEB J 2018; 32:3680-3688. [PMID: 29455573 DOI: 10.1096/fj.201701278r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
β2-Adrenergic receptors (β2ARs) desensitize during continuous agonist activation, which manifests clinically as tachyphylaxis. β-Agonist desensitization of β2ARs in human airway smooth muscle (HASM) cells is recognized in the treatment of asthma and may be related to poor outcomes. Rapid events in desensitization include receptor phosphorylation and internalization, but mechanisms responsible for the decrease in receptor protein after prolonged agonist exposure (down-regulation) are ill defined. The microRNA (miRNA) let-7f regulates β2AR expression by translational repression. In cultured HASM cells from nonasthmatic and asthmatic lungs, 18 h of β-agonist exposure increased let-7f by 2-3-fold, concomitant with a ∼90% decrease in β2ARs. Inhibition of let-7f attenuated this down-regulation response by ∼50%. The let-7f increase was found to be cAMP/PKA-dependent. The mechanism of the let-7f increase was found by chromatin immunoprecipitation to be from activated cAMP response element-binding protein (CREB) binding to the let-7f promoter, thereby increasing let-7f expression. Knockdown of CREB attenuated agonist-promoted β2AR down-regulation by ∼50%. Thus, β2AR down-regulation occurs as a result of not only internalized receptor degradation but also a novel cAMP/PKA/CREB-mediated increase in let-7f, which causes enhanced repression of the β2AR gene, adrenoreceptor β2 ( ADRB2) translation and represents ∼50% of the net loss of receptors observed after prolonged agonist exposure. This mechanism is apparent in asthmatic HASM cells, indicating relevance in a disease model.-Kim, D., Cho, S., Woo, J. A., Liggett, S. B. A CREB-mediated increase in miRNA let-7f during prolonged β-agonist exposure: a novel mechanism of β2-adrenergic receptor down-regulation in airway smooth muscle.
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Affiliation(s)
- Donghwa Kim
- Center for Personalized Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Soomin Cho
- Center for Personalized 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; and
| | - Stephen B Liggett
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA; and.,Department of Internal Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
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18
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Kim D, Woo JA, Geffken E, An SS, Liggett SB. Coupling of Airway Smooth Muscle Bitter Taste Receptors to Intracellular Signaling and Relaxation Is via G αi1,2,3. Am J Respir Cell Mol Biol 2017; 56:762-771. [PMID: 28145731 DOI: 10.1165/rcmb.2016-0373oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bitter taste receptors (TAS2Rs) are expressed on human airway smooth muscle (HASM) and evoke marked relaxation. Agonist interaction with TAS2Rs activates phospholipase C and increases compartmentalized intracellular Ca2+ ([Ca2+]i) via inositol 1,4,5 triphosphate. In taste cells, the G protein gustducin couples TAS2R to phospholipase C; however, we find very low levels of Gαgust mRNA or protein in HASM. We hypothesized that another G protein in HASM transmits TAS2R function. TAS2R signaling to [Ca2+]i, extracellular signal-regulated kinase (ERK) 1/2, and physiologic relaxation was sensitive to pertussis toxin, confirming a role for a member of the Gi family. α subunit expression in HASM was Gαi2 > Gαi1 = Gαi3 > Gαtrans1 ≈ Gαtrans2, with Gαgust and Gαo at the limits of detection (>100-fold lower than Gαi2). Small interfering RNA knockdowns in HASM showed losses of [Ca2+]i and ERK1/2 signaling when Gαi1, Gαi2, or Gαi3 were reduced. Gαtrans1 and Gαtrans2 knockdowns had no effect on [Ca2+]i and a minimal, transient effect on ERK1/2 phosphorylation. Furthermore, Gαgust and Gαo knockdowns did not affect any TAS2R signaling. In overexpression experiments in human embryonic kidney-293T cells, we confirmed an agonist-dependent physical interaction between TAS2R14 and Gαi2. ASM cells from transgenic mice expressing a peptide inhibitor of Gαi2 had attenuated relaxation to TAS2R agonist. These data indicate that, unlike in taste cells, TAS2Rs couple to the prevalent G proteins, Gαi1, Gαi2, and Gαi3, with no evidence for functional coupling to Gαgust. This absence of function for the "canonical" TAS2R G protein in HASM may be due to the very low expression of Gαgust, indicating that TAS2Rs can optionally couple to several G proteins in a cell type-dependent manner contingent upon G protein expression.
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Affiliation(s)
- Donghwa Kim
- 1 Department of Medicine and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, Florida
| | - Jung A Woo
- 1 Department of Medicine and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, Florida
| | - Ezekiel Geffken
- 2 Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; and
| | - Steven S An
- 2 Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; and
| | - Stephen B Liggett
- 3 Departments of Internal Medicine and Molecular Pharmacology and Physiology, and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, Florida
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19
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Carey RM, Workman AD, Hatten KM, Siebert AP, Brooks SG, Chen B, Adappa ND, Palmer JN, Kennedy DW, Lee RJ, Cohen NA. Denatonium-induced sinonasal bacterial killing may play a role in chronic rhinosinusitis outcomes. Int Forum Allergy Rhinol 2017; 7:699-704. [PMID: 28544530 DOI: 10.1002/alr.21949] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 04/05/2017] [Accepted: 04/10/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND Sinonasal bitter taste receptors (T2Rs) contribute to upper airway innate immunity and correlate with chronic rhinosinusitis (CRS) clinical outcomes. A subset of T2Rs expressed on sinonasal solitary chemosensory cells (SCCs) are activated by denatonium, resulting in a calcium-mediated secretion of bactericidal antimicrobial peptides (AMPs) in neighboring ciliated epithelial cells. We hypothesized that there is patient variability in the amount of bacterial killing induced by different concentrations of denatonium and that the differences correlate with CRS clinical outcomes. METHODS Bacterial growth inhibition was quantified after mixing bacteria with airway surface liquid (ASL) collected from denatonium-stimulated sinonasal air-liquid interface (ALI) cultures. Patient ASL bacterial killing at 0.1 mM denatonium and baseline characteristics and sinus surgery outcomes were compared between these populations. RESULTS There is variability in the degree of denatonium-induced bacterial killing between patients. In CRS with nasal polyps (CRSwNP), patients with increased bacterial killing after stimulation with low levels of denatonium undergo significantly more functional endoscopic sinus surgeries (FESSs) (p = 0.037) and have worse 6-month post-FESS 22-item Sino-Nasal Outcome Test (SNOT-22) scores (p = 0.012). CONCLUSION Bacterial killing after stimulation with low levels of denatonium correlates with number of prior FESS and postoperative SNOT-22 scores in CRSwNP. Some symptoms of CRS in patients with hyperresponsiveness to low levels of denatonium may be due to increased airway immune activity or inherent disease severity.
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Affiliation(s)
- Ryan M Carey
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Alan D Workman
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Kyle M Hatten
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Adam P Siebert
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Steven G Brooks
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Bei Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Nithin D Adappa
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - James N Palmer
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - David W Kennedy
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Robert J Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Noam A Cohen
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA.,Philadelphia Veterans Administration Medical Center Surgical Services, Philadelphia, PA.,Monell Chemical Senses Center, Philadelphia, PA
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20
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Hariri BM, McMahon DB, Chen B, Freund JR, Mansfield CJ, Doghramji LJ, Adappa ND, Palmer JN, Kennedy DW, Reed DR, Jiang P, Lee RJ. Flavones modulate respiratory epithelial innate immunity: Anti-inflammatory effects and activation of the T2R14 receptor. J Biol Chem 2017; 292:8484-8497. [PMID: 28373278 DOI: 10.1074/jbc.m116.771949] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/21/2017] [Indexed: 12/18/2022] Open
Abstract
Chronic rhinosinusitis has a significant impact on patient quality of life, creates billions of dollars of annual healthcare costs, and accounts for ∼20% of adult antibiotic prescriptions in the United States. Because of the rise of resistant microorganisms, there is a critical need to better understand how to stimulate and/or enhance innate immune responses as a therapeutic modality to treat respiratory infections. We recently identified bitter taste receptors (taste family type 2 receptors, or T2Rs) as important regulators of sinonasal immune responses and potentially important therapeutic targets. Here, we examined the immunomodulatory potential of flavones, a class of flavonoids previously demonstrated to have antibacterial and anti-inflammatory effects. Some flavones are also T2R agonists. We found that several flavones inhibit Muc5AC and inducible NOS up-regulation as well as cytokine release in primary and cultured airway cells in response to several inflammatory stimuli. This occurs at least partly through inhibition of protein kinase C and receptor tyrosine kinase activity. We also demonstrate that sinonasal ciliated epithelial cells express T2R14, which closely co-localizes (<7 nm) with the T2R38 isoform. Heterologously expressed T2R14 responds to multiple flavones. These flavones also activate T2R14-driven calcium signals in primary cells that activate nitric oxide production to increase ciliary beating and mucociliary clearance. TAS2R38 polymorphisms encode functional (PAV: proline, alanine, and valine at positions 49, 262, and 296, respectively) or non-functional (AVI: alanine, valine, isoleucine at positions 49, 262, and 296, respectively) T2R38. Our data demonstrate that T2R14 in sinonasal cilia is a potential therapeutic target for upper respiratory infections and that flavones may have clinical potential as topical therapeutics, particularly in T2R38 AVI/AVI individuals.
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Affiliation(s)
| | | | - Bei Chen
- Department of Otorhinolaryngology-Head and Neck Surgery
| | | | | | | | | | | | | | - Danielle R Reed
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Robert J Lee
- Department of Otorhinolaryngology-Head and Neck Surgery; Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia.
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21
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An SS, Liggett SB. Taste and smell GPCRs in the lung: Evidence for a previously unrecognized widespread chemosensory system. Cell Signal 2017; 41:82-88. [PMID: 28167233 DOI: 10.1016/j.cellsig.2017.02.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/02/2017] [Indexed: 12/13/2022]
Abstract
Taste and smell receptor expression has been traditionally limited to the tongue and nose. We have identified bitter taste receptors (TAS2Rs) and olfactory receptors (ORs) on human airway smooth muscle (HASM) cells. TAS2Rs signal to PLCβ evoking an increase in [Ca2+]i causing membrane hyperpolarization and marked HASM relaxation ascertained by single cell, ex vivo, and in vivo methods. The presence of TAS2Rs in the lung was unexpected, as was the bronchodilatory function which has been shown to be due to signaling within specific microdomains of the cell. Unlike β2-adrenergic receptor-mediated bronchodilation, TAS2R function is not impaired in asthma and shows little tachyphylaxis. HASM ORs do not bronchodilate, but rather modulate cytoskeletal remodeling and hyperplasia, two cardinal features of asthma. We have shown that short chain fatty acids, byproducts of fermentation of polysaccharides by the gut microbiome, activate HASM ORs. This establishes a non-immune gut-lung mechanism that ties observations on gut microbial communities to asthma phenotypes. Subsequent studies by multiple investigators have revealed expression and specialized functions of TAS2Rs and ORs in multiple cell-types and organs throughout the body. Collectively, the data point towards a previously unrecognized chemosensory system which recognizes endogenous and exogenous agonists. These receptors and their ligands play roles in normal homeostatic functions, predisposition or adaptation to disease, and represent drug targets for novel therapeutics.
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Affiliation(s)
- Steven S An
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street, Baltimore, MD 21205, United States.
| | - Stephen B Liggett
- Department of Internal Medicine, Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., MDC 2, Tampa, FL 33612, United States; Department of Pharmacology and Physiology, Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., MDC 2, Tampa, FL 33612, United States.
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22
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Prakash YS. Emerging concepts in smooth muscle contributions to airway structure and function: implications for health and disease. Am J Physiol Lung Cell Mol Physiol 2016; 311:L1113-L1140. [PMID: 27742732 DOI: 10.1152/ajplung.00370.2016] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/06/2016] [Indexed: 12/15/2022] Open
Abstract
Airway structure and function are key aspects of normal lung development, growth, and aging, as well as of lung responses to the environment and the pathophysiology of important diseases such as asthma, chronic obstructive pulmonary disease, and fibrosis. In this regard, the contributions of airway smooth muscle (ASM) are both functional, in the context of airway contractility and relaxation, as well as synthetic, involving production and modulation of extracellular components, modulation of the local immune environment, cellular contribution to airway structure, and, finally, interactions with other airway cell types such as epithelium, fibroblasts, and nerves. These ASM contributions are now found to be critical in airway hyperresponsiveness and remodeling that occur in lung diseases. This review emphasizes established and recent discoveries that underline the central role of ASM and sets the stage for future research toward understanding how ASM plays a central role by being both upstream and downstream in the many interactive processes that determine airway structure and function in health and disease.
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Affiliation(s)
- Y S Prakash
- Departments of Anesthesiology, and Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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