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Abstract
Although tuft cells were discovered over 60 years ago, their functions have long been enigmatic, especially in human health. Nonetheless, tuft cells have recently emerged as key orchestrators of the host response to diverse microbial infections in the gut and airway. While tuft cells are epithelial in origin, they exhibit functions akin to immune cells and mediate important interkingdom interactions between the host and helminths, protists, viruses, and bacteria. With broad intra- and intertissue heterogeneity, tuft cells sense and respond to microbes with exquisite specificity. Tuft cells can recognize helminth and protist infection, driving a type 2 immune response to promote parasite expulsion. Tuft cells also serve as the primary physiologic target of persistent murine norovirus (MNV) and promote immune evasion. Recently, tuft cells were also shown to be infected by rotavirus. Other viral infections, such as influenza A virus, can induce tuft cell–dependent tissue repair. In the context of coinfection, tuft cells promote neurotropic flavivirus replication by dampening antiviral adaptive immune responses. Commensal and pathogenic bacteria can regulate tuft cell abundance and function and, in turn, tuft cells are implicated in modulating bacterial infiltration and mucosal barrier integrity. However, the contribution of tuft cells to microbial sensing in humans and their resulting effector responses are poorly characterized. Herein, we aim to provide a comprehensive overview of microbial activation of tuft cells with an emphasis on tuft cell heterogeneity and differences between mouse and human tuft cell biology as it pertains to human health and disease.
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Affiliation(s)
- Madison S. Strine
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Craig B. Wilen
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut, United States of America
- Yale Cancer Center, Yale School of Medicine, New Haven, Connecticut, United States of America
- * E-mail: ,
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2
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Development of epithelial cholinergic chemosensory cells of the urethra and trachea of mice. Cell Tissue Res 2021; 385:21-35. [PMID: 33616728 PMCID: PMC8270884 DOI: 10.1007/s00441-021-03424-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 01/24/2021] [Indexed: 12/24/2022]
Abstract
Cholinergic chemosensory cells (CCC) are infrequent epithelial cells with immunosensor function, positioned in mucosal epithelia preferentially near body entry sites in mammals including man. Given their adaptive capacity in response to infection and their role in combatting pathogens, we here addressed the time points of their initial emergence as well as their postnatal development from first exposure to environmental microbiota (i.e., birth) to adulthood in urethra and trachea, utilizing choline acetyltransferase (ChAT)-eGFP reporter mice, mice with genetic deletion of MyD88, toll-like receptor-2 (TLR2), TLR4, TLR2/TLR4, and germ-free mice. Appearance of CCC differs between the investigated organs. CCC of the trachea emerge during embryonic development at E18 and expand further after birth. Urethral CCC show gender diversity and appear first at P6-P10 in male and at P11-P20 in female mice. Urethrae and tracheae of MyD88- and TLR-deficient mice showed significantly fewer CCC in all four investigated deficient strains, with the effect being most prominent in the urethra. In germ-free mice, however, CCC numbers were not reduced, indicating that TLR2/4-MyD88 signaling, but not vita-PAMPs, governs CCC development. Collectively, our data show a marked postnatal expansion of CCC populations with distinct organ-specific features, including the relative impact of TLR2/4-MyD88 signaling. Strong dependency on this pathway (urethra) correlates with absence of CCC at birth and gender-specific initial development and expansion dynamics, whereas moderate dependency (trachea) coincides with presence of first CCC at E18 and sex-independent further development.
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3
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Abstract
G protein-coupled receptors (GPCRs) play a central role in regulating the functions of a diverse range of cell types in the airway. Taste 2 receptor (T2R) family of GPCRs is responsible for the transduction of bitter taste; however, recent studies have demonstrated that different subtypes of T2Rs and key components of T2R signaling are expressed in several extra-oral tissues including airways with many physiological roles. In the lung, expression of T2Rs has been confirmed in multiple airway cell types including airway smooth muscle (ASM) cells, various epithelial cell subtypes, and on both resident and migratory immune cells. Most importantly, activation of T2Rs with a variety of putative agonists elicits unique signaling in ASM and specialized airway epithelial cells resulting in the inhibition of ASM contraction and proliferation, promotion of ciliary motility, and innate immune response in chemosensory airway epithelial cells. Here we discuss the expression of T2Rs and the mechanistic basis of their function in the structural cells of the airways with some useful insights on immune cells in the context of allergic asthma and other upper airway inflammatory disorders. Emphasis on T2R biology and pharmacology in airway cells has an ulterior goal of exploiting T2Rs for therapeutic benefit in obstructive airway diseases.
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Kim D, Cho S, Castaño MA, Panettieri RA, Woo JA, Liggett SB. Biased TAS2R Bronchodilators Inhibit Airway Smooth Muscle Growth by Downregulating Phosphorylated Extracellular Signal-regulated Kinase 1/2. Am J Respir Cell Mol Biol 2019; 60:532-540. [PMID: 30365340 DOI: 10.1165/rcmb.2018-0189oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Bitter taste receptor (TAS2R) agonists dilate airways by receptor-dependent smooth muscle relaxation. Besides their coupling to relaxation, we have found that human airway smooth muscle (HASM) cell TAS2Rs activate (phosphorylate) extracellular signal-related kinase 1/2 (ERK1/2), but the cellular effects are not known. In the present study, we show in HASM cells that TAS2R agonists initially stimulate phosphorylated ERK1/2 (pERK1/2) but by 24 hours cause a marked (50-70%) downregulation of pERK1/2 without a change in total ERK1/2. It was hypothesized that TAS2R agonists suppress cell growth through this pERK1/2 downregulation. Agonist-dependent inhibition of cell proliferation was indeed found in HASM cells derived from normal and asthmatic human lungs, as well as in an immortalized HASM cell line. pERK1/2 downregulation was linked to downregulation of the upstream kinase MEK1/2 (mitogen-activated protein kinase/extracellular signal-regulated kinase). Various structurally diverse TAS2R agonists evoked a range of inhibition of HASM proliferation, the magnitude of which directly correlated with the downregulation of pERK1/2 (R2 = 0.86). Some TAS2R agonists were as effective as pharmacological inhibitors of Raf1 and MEK1/2 in suppressing growth. siRNA silencing of TAS2Rs (subtypes 10, 14, and 31) ablated the pERK1/2 and growth-inhibitory effects of TAS2R agonists. These phenotypes were attenuated by inhibiting the TAS2R G protein Gαi and by knocking down β-arrestin 1/2, indicating a dual pathway, although there may be additional mechanisms involved in this HASM TAS2R multidimensional signaling. Thus, TAS2R agonist structure can be manipulated to maintain the relaxation response and can be biased toward suppression of HASM growth. The latter response is of potential therapeutic benefit in asthma, in which an increase in smooth muscle mass contributes to airway obstruction.
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Affiliation(s)
| | - Soomin Cho
- 2 Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California; and
| | | | - Reynold A Panettieri
- 3 Rutgers Institute for Translational Medicine and Science, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
| | - Jung A Woo
- 4 Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida
| | - Stephen B Liggett
- 1 Department of Medicine and.,4 Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida
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Ting HA, von Moltke J. The Immune Function of Tuft Cells at Gut Mucosal Surfaces and Beyond. THE JOURNAL OF IMMUNOLOGY 2019; 202:1321-1329. [PMID: 30782851 DOI: 10.4049/jimmunol.1801069] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/21/2018] [Indexed: 12/25/2022]
Abstract
Tuft cells were first discovered in epithelial barriers decades ago, but their function remained unclear until recently. In the last 2 years, a series of studies has provided important advances that link tuft cells to infectious diseases and the host immune responses. Broadly, a model has emerged in which tuft cells use chemosensing to monitor their surroundings and translate environmental signals into effector functions that regulate immune responses in the underlying tissue. In this article, we review the current understanding of tuft cell immune function in the intestines, airways, and thymus. In particular, we discuss the role of tuft cells in type 2 immunity, norovirus infection, and thymocyte development. Despite recent advances, many fundamental questions about the function of tuft cells in immunity remain to be answered.
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Affiliation(s)
- Hung-An Ting
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98109
| | - Jakob von Moltke
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98109
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Emerging Concepts in Brain Glucose Metabolic Functions: From Glucose Sensing to How the Sweet Taste of Glucose Regulates Its Own Metabolism in Astrocytes and Neurons. Neuromolecular Med 2018; 20:281-300. [DOI: 10.1007/s12017-018-8503-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/13/2018] [Indexed: 12/16/2022]
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Verbeurgt C, Veithen A, Carlot S, Tarabichi M, Dumont JE, Hassid S, Chatelain P. The human bitter taste receptor T2R38 is broadly tuned for bacterial compounds. PLoS One 2017; 12:e0181302. [PMID: 28902853 PMCID: PMC5597121 DOI: 10.1371/journal.pone.0181302] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 06/24/2017] [Indexed: 11/18/2022] Open
Abstract
T2R38 has been shown to be a specific bacterial detector implicated in innate immune defense mechanism of human upper airway. Several clinical studies have demonstrated that this receptor is associated with the development of chronic rhinosinusitis (CRS). T2R38 was previously reported to bind to homoserine lactones (HSL), quorum sensing molecules specific of Pseudomonas Aeruginosa and other gram negative species. Nevertheless, these bacteria are not the major pathogens found in CRS. Here we report on the identification of bacterial metabolites acting as new agonists of T2R38 based on a single cell calcium imaging study. Two quorum sensing molecules (Agr D1 thiolactone from Staphylococcus Aureus and CSP-1 from Streptococcus Pneumoniae) and a list of 32 bacterial metabolites from pathogens frequently implicated in CRS were tested. First, we observed that HSL failed to activate T2R38 in our experimental system, but that the dimethylsulfoxide (DMSO), used as a solvent for these lactones may, by itself, account for the agonistic effect previously described. Secondly, we showed that both Agr D1 thiolactone and CSP-1 are inactive but that at least 7 bacterial metabolites (acetone, 2-butanone, 2-pentanone, 2-methylpropanal, dimethyl disulfide, methylmercaptan, γ-butyrolactone) are able to specifically trigger this receptor. T2R38 is thus much more broadly tuned for bacterial compounds than previously thought.
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Affiliation(s)
- Christophe Verbeurgt
- Department of Otorhinolaryngology, Erasme University Hospital, Free University of Brussels, Brussels, Belgium
- * E-mail:
| | | | - Sébastien Carlot
- Department of Otorhinolaryngology, Erasme University Hospital, Free University of Brussels, Brussels, Belgium
| | - Maxime Tarabichi
- Institute of Interdisciplinary Research in human and molecular Biology, Free University of Brussels, Brussels, Belgium
| | - Jacques E. Dumont
- Institute of Interdisciplinary Research in human and molecular Biology, Free University of Brussels, Brussels, Belgium
| | - Sergio Hassid
- Department of Otorhinolaryngology, Erasme University Hospital, Free University of Brussels, Brussels, Belgium
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Lossow K, Hübner S, Roudnitzky N, Slack JP, Pollastro F, Behrens M, Meyerhof W. Comprehensive Analysis of Mouse Bitter Taste Receptors Reveals Different Molecular Receptive Ranges for Orthologous Receptors in Mice and Humans. J Biol Chem 2016; 291:15358-77. [PMID: 27226572 DOI: 10.1074/jbc.m116.718544] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Indexed: 11/06/2022] Open
Abstract
One key to animal survival is the detection and avoidance of potentially harmful compounds by their bitter taste. Variable numbers of taste 2 receptor genes expressed in the gustatory end organs enable bony vertebrates (Euteleostomi) to recognize numerous bitter chemicals. It is believed that the receptive ranges of bitter taste receptor repertoires match the profiles of bitter chemicals that the species encounter in their diets. Human and mouse genomes contain pairs of orthologous bitter receptor genes that have been conserved throughout evolution. Moreover, expansions in both lineages generated species-specific sets of bitter taste receptor genes. It is assumed that the orthologous bitter taste receptor genes mediate the recognition of bitter toxins relevant for both species, whereas the lineage-specific receptors enable the detection of substances differently encountered by mice and humans. By challenging 34 mouse bitter taste receptors with 128 prototypical bitter substances in a heterologous expression system, we identified cognate compounds for 21 receptors, 19 of which were previously orphan receptors. We have demonstrated that mouse taste 2 receptors, like their human counterparts, vary greatly in their breadth of tuning, ranging from very broadly to extremely narrowly tuned receptors. However, when compared with humans, mice possess fewer broadly tuned receptors and an elevated number of narrowly tuned receptors, supporting the idea that a large receptor repertoire is the basis for the evolution of specialized receptors. Moreover, we have demonstrated that sequence-orthologous bitter taste receptors have distinct agonist profiles. Species-specific gene expansions have enabled further diversification of bitter substance recognition spectra.
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Affiliation(s)
- Kristina Lossow
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Sandra Hübner
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Natacha Roudnitzky
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Jay P Slack
- the Givaudan Flavors Corporation, Cincinnati, Ohio 45216, and
| | - Federica Pollastro
- the Department of Drug Sciences, University of Eastern Piemonte, 28100 Novara, Italy
| | - Maik Behrens
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany,
| | - Wolfgang Meyerhof
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
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Merigo F, Boschi F, Lasconi C, Benati D, Sbarbati A. Molecules implicated in glucose homeostasis are differentially expressed in the trachea of lean and obese Zucker rats. Eur J Histochem 2016; 60:2557. [PMID: 26972710 PMCID: PMC4800246 DOI: 10.4081/ejh.2016.2557] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 11/18/2015] [Accepted: 11/30/2015] [Indexed: 01/16/2023] Open
Abstract
Recent studies indicate that the processes mediated by the (T1R2/T1R3) glucose/sugar receptor of gustatory cells in the tongue, and hormones like leptin and ghrelin contribute to the regulation of glucose homeostasis. Altered plasma levels of leptin and ghrelin are associated with obesity both in humans and rodents. In the present study, we evaluated the ultrastructure of the mucosa, and the expression of molecules implicated in the regulation of glucose homeostasis (GLUT2, SGLT1, T1R3, ghrelin and its receptor) in the trachea of an animal model of obesity (Zucker rats). We found that the tracheal epithelium of obese animals was characterized by the presence of poorly differentiated cells. Ciliated and secretory cells were the cell lineages with greatest loss of differentiation. Severe epithelial alterations were associated with marked deposit of extracellular matrix in the lamina propria. The expression pattern of GLUT2 and SGLT1 glucose transporters was similar in the trachea of both the Zucker rat genotypes, whereas that of T1R3 was reduced in ciliated cells of obese rats. A different immunolocalization for ghrelin was also found in the trachea of obese rats. In conclusion, the tracheal morphological alterations in obese animals seem to compromise the expression of molecules involved in the homeostasis of glucose.
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Balloy V, Varet H, Dillies MA, Proux C, Jagla B, Coppée JY, Tabary O, Corvol H, Chignard M, Guillot L. Normal and Cystic Fibrosis Human Bronchial Epithelial Cells Infected with Pseudomonas aeruginosa Exhibit Distinct Gene Activation Patterns. PLoS One 2015; 10:e0140979. [PMID: 26485688 PMCID: PMC4618526 DOI: 10.1371/journal.pone.0140979] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/25/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND AIMS In cystic fibrosis (CF), Pseudomonas aeruginosa is not eradicated from the lower respiratory tract and is associated with epithelial inflammation that eventually causes tissue damage. To identify the molecular determinants of an effective response to P. aeruginosa infection, we performed a transcriptomic analysis of primary human bronchial epithelial cells from healthy donors (CTRL) 2, 4, and 6 h after induced P. aeruginosa infection. Compared to noninfected cells, infected cells showed changes in gene activity, which were most marked 6 h postinfection and usually consisted in upregulation. RESULTS By comparing for each time point of infection, the transcriptomic response of epithelial cells from CF patients and healthy donors, we identified 851, 638, 667, and 980 differentially expressed genes 0, 2, 4, and 6 h postinfection, respectively. Gene selection followed by bioinformatic analysis showed that most of the differentially expressed genes, either up- or downregulated, were in the protein-binding and catalytic gene-ontology categories. Finally, we established that the protein products of the genes exhibiting the greatest differential upregulation (CSF2, CCL2, TNF, CSF3, MMP1, and MMP10) between CF patients and CTRL were produced in higher amounts by infected cells from CF patients versus CTRL. CONCLUSIONS The differentially expressed genes in CF patients may constitute a signature for a detrimental inflammatory response and for an inefficient P. aeruginosa host-cell response.
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Affiliation(s)
- Viviane Balloy
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
| | - Hugo Varet
- Institut Pasteur, Plate-forme Transcriptome Epigenome, Centre Innovation et Recherche Technologiques, Paris, France
| | - Marie-Agnès Dillies
- Institut Pasteur, Plate-forme Transcriptome Epigenome, Centre Innovation et Recherche Technologiques, Paris, France
| | - Caroline Proux
- Institut Pasteur, Plate-forme Transcriptome Epigenome, Centre Innovation et Recherche Technologiques, Paris, France
| | - Bernd Jagla
- Institut Pasteur, Plate-forme Transcriptome Epigenome, Centre Innovation et Recherche Technologiques, Paris, France
| | - Jean-Yves Coppée
- Institut Pasteur, Plate-forme Transcriptome Epigenome, Centre Innovation et Recherche Technologiques, Paris, France
| | - Olivier Tabary
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
| | - Harriet Corvol
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
- Pneumologie pédiatrique, AP-HP, Hôpital Trousseau, Paris, France
| | - Michel Chignard
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
| | - Loïc Guillot
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
- * E-mail:
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Losa D, Köhler T, Bacchetta M, Saab JB, Frieden M, van Delden C, Chanson M. Airway Epithelial Cell Integrity Protects from Cytotoxicity of Pseudomonas aeruginosa Quorum-Sensing Signals. Am J Respir Cell Mol Biol 2015; 53:265-75. [PMID: 25562674 DOI: 10.1165/rcmb.2014-0405oc] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cell-to-cell communication via gap junctions regulates airway epithelial cell homeostasis and maintains the epithelium host defense. Quorum-sensing molecules produced by Pseudomonas aeruginosa coordinate the expression of virulence factors by this respiratory pathogen. These bacterial signals may also incidentally modulate mammalian airway epithelial cell responses to the pathogen, a process called interkingdom signaling. We investigated the interactions between the P. aeruginosa N-3-oxo-dodecanoyl-L-homoserine lactone (C12) quorum-sensing molecule and human airway epithelial cell gap junctional intercellular communication (GJIC). C12 degradation and its effects on cells were monitored in various airway epithelial cell models grown under nonpolarized and polarized conditions. Its concentration was further monitored in daily tracheal aspirates of colonized intubated patients. C12 rapidly altered epithelial integrity and decreased GJIC in nonpolarized airway epithelial cells, whereas other quorum-sensing molecules had no effect. The effects of C12 were dependent on [Ca(2+)]i and could be prevented by inhibitors of Src tyrosine family and Rho-associated protein kinases. In contrast, polarized airway cells grown on Transwell filters were protected from C12 except when undergoing repair after wounding. In vivo during colonization of intubated patients, C12 did not accumulate, but it paralleled bacterial densities. In vitro C12 degradation, a reaction catalyzed by intracellular paraoxonase 2 (PON2), was impaired in nonpolarized cells, whereas PON2 expression was increased during epithelial polarization. The cytotoxicity of C12 on nonpolarized epithelial cells, combined with its impaired degradation allowing its accumulation, provides an additional pathogenic mechanism for P. aeruginosa infections.
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Affiliation(s)
| | - Thilo Köhler
- 2 Service of Infectious Diseases and Department of Microbiology and Molecular Genetics, and
| | - Marc Bacchetta
- 1 Laboratory of Clinical Investigation III.,3 Department of Cell Physiology and Metabolism, Geneva University Hospitals and Medical School of the University of Geneva, Geneva, Switzerland
| | - Joanna Bou Saab
- 1 Laboratory of Clinical Investigation III.,3 Department of Cell Physiology and Metabolism, Geneva University Hospitals and Medical School of the University of Geneva, Geneva, Switzerland
| | - Maud Frieden
- 3 Department of Cell Physiology and Metabolism, Geneva University Hospitals and Medical School of the University of Geneva, Geneva, Switzerland
| | - Christian van Delden
- 2 Service of Infectious Diseases and Department of Microbiology and Molecular Genetics, and
| | - Marc Chanson
- 1 Laboratory of Clinical Investigation III.,3 Department of Cell Physiology and Metabolism, Geneva University Hospitals and Medical School of the University of Geneva, Geneva, Switzerland
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Camoretti-Mercado B, Pauer SH, Yong HM, Smith DC, Deshpande DA, An SS, Liggett SB. Pleiotropic Effects of Bitter Taste Receptors on [Ca2+]i Mobilization, Hyperpolarization, and Relaxation of Human Airway Smooth Muscle Cells. PLoS One 2015; 10:e0131582. [PMID: 26121686 PMCID: PMC4485472 DOI: 10.1371/journal.pone.0131582] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/03/2015] [Indexed: 01/25/2023] Open
Abstract
Asthma is characterized by airway inflammation and airflow obstruction from human airway smooth muscle (HASM) constriction due to increased local bronchoconstrictive substances. We have recently found bitter taste receptors (TAS2Rs) on HASM, which increase [Ca2+]i and relax the muscle. We report here that some, but not all, TAS2R agonists decrease [Ca2+]i and relax HASM contracted by G-protein coupled receptors (GPCRs) that stimulate [Ca2+]i. This suggests both a second pathway by which TAS2Rs relax, and, a heterogeneity of the response phenotype. We utilized eight TAS2R agonists and five procontractile GPCR agonists in cultured HASM cells. We find that heterogeneity in the inhibitory response hinges on which procontractile GPCR is activated. For example, chloroquine inhibits [Ca2+]i increases from histamine, but failed to inhibit [Ca2+]i increases from endothelin-1. Conversely, aristolochic acid inhibited [Ca2+]i increases from endothelin-1 but not histamine. Other dichotomous responses were found when [Ca2+]i was stimulated by bradykinin, angiotensin, and acetylcholine. There was no association between [Ca2+]i inhibition and TAS2R subtype, nor whether [Ca2+]i was increased by Gq- or Gi-coupled GPCRs. Selected studies revealed a correlation between [Ca2+]i inhibition and HASM cell-membrane hyperpolarization. To demonstrate physiologic correlates, ferromagnetic beads were attached to HASM cells and cell stiffness measured by magnetic twisting cytometry. Consistent with the [Ca2+]i inhibition results, chloroquine abolished the cell stiffening response (contraction) evoked by histamine but not by endothelin-1, while aristolochic acid inhibited cell stiffening from endothelin-1, but not from histamine. In studies using intact human bronchi, these same differential responses were found. Those TAS2R agonists that decreased [Ca2+]i, promoted hyperpolarization, and decreased HASM stiffness, caused relaxation of human airways. Thus TAS2Rs relax HASM in two ways: a low-efficiency de novo [Ca2+]i stimulation, and, a high-efficiency inhibition of GPCR-stimulated [Ca2+]i. Furthermore, there is an interaction between TAS2Rs and some GPCRs that facilitates this [Ca2+]i inhibition limb.
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Affiliation(s)
- Blanca Camoretti-Mercado
- Department of Medicine and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL, United States of America
| | - Susan H. Pauer
- Department of Medicine and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL, United States of America
| | - Hwan Mee Yong
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Dan’elle C. Smith
- Department of Medicine and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL, United States of America
| | - Deepak A. Deshpande
- Department of Medicine and Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA, United States of America
| | - Steven S. An
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Stephen B. Liggett
- Department of Medicine and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL, United States of America
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, FL, United States of America
- * E-mail:
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Welcome MO, Mastorakis NE, Pereverzev VA. Sweet taste receptor signaling network: possible implication for cognitive functioning. Neurol Res Int 2015; 2015:606479. [PMID: 25653876 PMCID: PMC4306214 DOI: 10.1155/2015/606479] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/20/2014] [Indexed: 01/01/2023] Open
Abstract
Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special "sweet" molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose) regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.
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Affiliation(s)
- Menizibeya O. Welcome
- World Scientific and Engineering Academy and Society, Ag. Ioannou Theologou 17-23, Zografou, 15773 Athens, Greece
| | - Nikos E. Mastorakis
- World Scientific and Engineering Academy and Society, Ag. Ioannou Theologou 17-23, Zografou, 15773 Athens, Greece
- Department of Industrial Engineering, Technical University of Sofia, 8 Kl. Ohridski Boulevard, 1000 Sofia, Bulgaria
| | - Vladimir A. Pereverzev
- Department of Normal Physiology, Belarusian State Medical University, Dzerzhinsky Avenue 83, 220116 Minsk, Belarus
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Xiong G, Redding K, Chen B, Cohen AS, Cohen NA. Non-specific immunostaining by a rabbit antibody against gustducin α subunit in mouse brain. J Histochem Cytochem 2014; 63:79-87. [PMID: 25411190 DOI: 10.1369/0022155414562838] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gustducin is a guanosine nucleotide-binding protein functionally coupled with taste receptors and thus originally identified in taste cells of the tongue. Recently, bitter taste receptors and gustducin have been detected in the airways, digestive tracts and brain. The existing studies showing taste receptors and gustducin in the brain were carried out exclusively on frozen sections. In order to avoid the technical shortcomings associated with frozen sectioning, we performed immunofluorescence staining using vibratome-cut sections from mouse brains. Using a rabbit gustducin antibody, we could not detect neurons or astrocytes as reported previously. Rather, we found dense fibers in the nucleus accumbens and periventricular areas. We assumed these staining patterns to be specific after confirmation with conventional negative control staining. For the verification of this finding, we stained gustducin knockout mouse brain and tongue sections with the same rabbit gustducin antibody. Whereas negative staining was confirmed in the tongue, intensive fibers were constantly stained in the brain. Moreover, immunostaining with a goat gustducin antibody could not demonstrate the fibers in the brain tissue. The present study implies a cross immunoreaction that occurs with the rabbit gustducin antibody in mouse brain samples, suggesting that the conventional negative controls may not be sufficient when an immunostaining pattern is to be verified.
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Affiliation(s)
- Guoxiang Xiong
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania (GX, ASC)
| | - Kevin Redding
- Monell Chemical Senses Center, Philadelphia, Pennsylvania (KR)
| | - Bei Chen
- Departments of Otorhinolaryngology - Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania (BC, NAC)
| | - Akiva S Cohen
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania (GX, ASC),Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (ASC)
| | - Noam A Cohen
- Departments of Otorhinolaryngology - Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania (BC, NAC)
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Taste Receptor Gene Expression Outside the Gustatory System. TOPICS IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1007/7355_2014_79] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Abstract
INTRODUCTION There is an unmet need for a new class of direct bronchodilators for the treatment of asthma and chronic obstructive lung disease. Unexpectedly, bitter taste receptors (TAS2Rs) have been localized on airway smooth muscle and when activated cause marked smooth muscle relaxation through a mechanism that is distinct from β2-adrenegic receptors. Thus TAS2R agonists have emerged as a novel class of bronchodilator. AREAS COVERED A synopsis of the TAS2R family and its biology for bitter taste perception on the tongue is provided, followed by a review of the identification and molecular and physiological characterization of TAS2R subtypes on human and mouse airway smooth muscle. The proposed molecular mechanisms leading to the relaxation response are provided, along with gaps in our understanding at certain points in the signaling cascade. Unresolved issues that may need to be considered for drug development are discussed. EXPERT OPINION TAS2R agonists show promise as a new class of highly efficacious bronchodilators for treatment of obstructive lung disease. With tens of thousands of known natural and synthetic bitter compounds, there is substantial diversity within the known agonists, and, a ready source of agents for screening and further development of an inhaled TAS2R agonist for therapeutic purposes.
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Affiliation(s)
- Stephen B Liggett
- University of South Florida Morsani College of Medicine, Departments of Internal Medicine and Molecular Pharmacology and Physiology , 12901 Bruce B. Downs Blvd, MDC02 Tampa, FL 33612 , USA.
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Lee RJ, Xiong G, Kofonow JM, Chen B, Lysenko A, Jiang P, Abraham V, Doghramji L, Adappa ND, Palmer JN, Kennedy DW, Beauchamp GK, Doulias PT, Ischiropoulos H, Kreindler JL, Reed DR, Cohen NA. T2R38 taste receptor polymorphisms underlie susceptibility to upper respiratory infection. J Clin Invest 2012; 122:4145-59. [PMID: 23041624 PMCID: PMC3484455 DOI: 10.1172/jci64240] [Citation(s) in RCA: 408] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 08/02/2012] [Indexed: 12/13/2022] Open
Abstract
Innate and adaptive defense mechanisms protect the respiratory system from attack by microbes. Here, we present evidence that the bitter taste receptor T2R38 regulates the mucosal innate defense of the human upper airway. Utilizing immunofluorescent and live cell imaging techniques in polarized primary human sinonasal cells, we demonstrate that T2R38 is expressed in human upper respiratory epithelium and is activated in response to acyl-homoserine lactone quorum-sensing molecules secreted by Pseudomonas aeruginosa and other gram-negative bacteria. Receptor activation regulates calcium-dependent NO production, resulting in stimulation of mucociliary clearance and direct antibacterial effects. Moreover, common polymorphisms of the TAS2R38 gene were linked to significant differences in the ability of upper respiratory cells to clear and kill bacteria. Lastly, TAS2R38 genotype correlated with human sinonasal gram-negative bacterial infection. These data suggest that T2R38 is an upper airway sentinel in innate defense and that genetic variation contributes to individual differences in susceptibility to respiratory infection.
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Affiliation(s)
- Robert J. Lee
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Guoxiang Xiong
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Jennifer M. Kofonow
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Bei Chen
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Anna Lysenko
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Peihua Jiang
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Valsamma Abraham
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Laurel Doghramji
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Nithin D. Adappa
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - James N. Palmer
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - David W. Kennedy
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Gary K. Beauchamp
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Paschalis-Thomas Doulias
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Harry Ischiropoulos
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - James L. Kreindler
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Danielle R. Reed
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
| | - Noam A. Cohen
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Division of Neurology, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Children’s Hospital of Philadelphia, Pennsylvania, USA.
Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Philadelphia Veterans Affairs Medical Center, Surgical Services, Philadelphia, Pennsylvania, USA
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Green BG. Chemesthesis and the chemical senses as components of a "chemofensor complex". Chem Senses 2011; 37:201-6. [PMID: 22210122 DOI: 10.1093/chemse/bjr119] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An important function of the chemical senses is to warn against dangerous biological and chemical agents in the environment. The discovery in recent years of "taste" receptor cells outside the oral cavity that appear to have protective functions has raised new questions about the nature and scope of the chemical senses in general and of chemesthesis in particular. The present paper briefly reviews these findings within the context of what is currently known about the body's chemically sensitive protective mechanisms, including nonsensory processes that help to expel or neutralize threatening agents once they have been encountered. It is proposed that this array of defense mechanisms constitutes a "chemofensor complex" in which chemesthesis is the most ubiquitous, functionally diverse, and interactive chemosensory component.
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Affiliation(s)
- Barry G Green
- The John B. Pierce Laboratory, New Haven, CT 06519, USA.
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20
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Zaborina O, Zaborin A, Romanowski K, Babrowski T, Alverdy J. Host stress and virulence expression in intestinal pathogens: development of therapeutic strategies using mice and C. elegans. Curr Pharm Des 2011; 17:1254-60. [PMID: 21470113 DOI: 10.2174/138161211795703771] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 03/18/2011] [Indexed: 12/29/2022]
Abstract
The intestinal tract of a host exposed to extreme physiologic stress and modern medical intervention represents a relatively unexplored yet important area of infection research, given the frequency with which this site becomes colonized by highly pathogenic microorganisms that cause subsequent sepsis. Our laboratory has focused on the host tissue derived environmental cues that are released into the intestinal tract during extreme physiologic stress that induce the expression of virulence in colonizing pathogens with the goal of developing novel gut directed therapies that maintain host pathogen neutrality through the course of host stress. Here we demonstrate that maintenance of phosphate sufficiency/ abundance within the intestinal microenvironment may be considered as a universal strategy to prevent virulence activation across a broad range of pathogens that colonize the gut and cause sepsis, given that phosphate depletion occurs following stress and is a universal cue that activates the virulence of a wide variety of organisms. Using small animal models (Caenorhabditis elegans and mice) to create local phosphate depletion at sites of colonization of Pseudomonas aeruginosa, a common cause of lethal gut-derived sepsis, we demonstrate the importance of maintaining phosphate sufficiency to suppress the expression of a lethal phenotype during extreme physiologic stress. The molecular details and potential therapeutic implications are reviewed.
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Affiliation(s)
- Olga Zaborina
- Department of Surgery, University of Chicago, Chicago, IL 60637, USA
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21
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Mayer ML, Sheridan JA, Blohmke CJ, Turvey SE, Hancock REW. The Pseudomonas aeruginosa autoinducer 3O-C12 homoserine lactone provokes hyperinflammatory responses from cystic fibrosis airway epithelial cells. PLoS One 2011; 6:e16246. [PMID: 21305014 PMCID: PMC3031552 DOI: 10.1371/journal.pone.0016246] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 12/07/2010] [Indexed: 12/02/2022] Open
Abstract
The discovery of novel antiinflammatory targets to treat inflammation in the cystic fibrosis (CF) lung stands to benefit patient populations suffering with this disease. The Pseudomonas aeruginosa quorum sensing autoinducer N-3-oxododecanoyl homoserine lactone (3O-C12) is an important bacterial virulence factor that has been reported to induce proinflammatory cytokine production from a variety of cell types. The goal of this study was to examine the ability of 3O-C12 to induce proinflammatory cytokine production in normal and CF bronchial epithelial cells, and better understand the cellular mechanisms by which this cytokine induction occurs. 3O-C12 was found to induce higher levels of IL-6 production in the CF cell lines IB3-1 and CuFi, compared to their corresponding control cell lines C38 and NuLi. Systems biology and network analysis revealed a high predominance of over-represented innate immune pathways bridged together by calcium-dependant transcription factors governing the transcriptional responses of A549 airway cells to stimulation with 3O-C12. Using calcium-flux assays, 3O-C12 was found to induce larger and more sustained increases in intracellular calcium in IB3-1 cells compared to C38, and blocking this calcium flux with BAPTA-AM reduced the production of IL-6 by IB3-1 to the levels produced by C38. These data suggest that 3O-C12 induces proinflammatory cytokine production in airway epithelial cells in a calcium-dependent manner, and that dysregulated calcium storage or signalling in CF cells results in an increased production of proinflammatory cytokines.
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Affiliation(s)
- Matthew L. Mayer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Jared A. Sheridan
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Christoph J. Blohmke
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- Child and Family Research Institute, BC Children's Hospital, Vancouver, Canada
| | - Stuart E. Turvey
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- Child and Family Research Institute, BC Children's Hospital, Vancouver, Canada
| | - Robert E. W. Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
- * E-mail:
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Tizzano M, Cristofoletti M, Sbarbati A, Finger TE. Expression of taste receptors in solitary chemosensory cells of rodent airways. BMC Pulm Med 2011; 11:3. [PMID: 21232137 PMCID: PMC3031280 DOI: 10.1186/1471-2466-11-3] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 01/13/2011] [Indexed: 02/05/2023] Open
Abstract
Background Chemical irritation of airway mucosa elicits a variety of reflex responses such as coughing, apnea, and laryngeal closure. Inhaled irritants can activate either chemosensitive free nerve endings, laryngeal taste buds or solitary chemosensory cells (SCCs). The SCC population lies in the nasal respiratory epithelium, vomeronasal organ, and larynx, as well as deeper in the airway. The objective of this study is to map the distribution of SCCs within the airways and to determine the elements of the chemosensory transduction cascade expressed in these SCCs. Methods We utilized a combination of immunohistochemistry and molecular techniques (rtPCR and in situ hybridization) on rats and transgenic mice where the Tas1R3 or TRPM5 promoter drives expression of green fluorescent protein (GFP). Results Epithelial SCCs specialized for chemoreception are distributed throughout much of the respiratory tree of rodents. These cells express elements of the taste transduction cascade, including Tas1R and Tas2R receptor molecules, α-gustducin, PLCβ2 and TrpM5. The Tas2R bitter taste receptors are present throughout the entire respiratory tract. In contrast, the Tas1R sweet/umami taste receptors are expressed by numerous SCCs in the nasal cavity, but decrease in prevalence in the trachea, and are absent in the lower airways. Conclusions Elements of the taste transduction cascade including taste receptors are expressed by SCCs distributed throughout the airways. In the nasal cavity, SCCs, expressing Tas1R and Tas2R taste receptors, mediate detection of irritants and foreign substances which trigger trigeminally-mediated protective airway reflexes. Lower in the respiratory tract, similar chemosensory cells are not related to the trigeminal nerve but may still trigger local epithelial responses to irritants. In total, SCCs should be considered chemoreceptor cells that help in preventing damage to the respiratory tract caused by inhaled irritants and pathogens.
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Affiliation(s)
- Marco Tizzano
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University of Colorado at Denver & Health Sciences Center, Aurora, CO, USA.
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Bitter taste receptors on airway smooth muscle bronchodilate by localized calcium signaling and reverse obstruction. Nat Med 2010; 16:1299-304. [PMID: 20972434 PMCID: PMC3066567 DOI: 10.1038/nm.2237] [Citation(s) in RCA: 459] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 09/09/2010] [Indexed: 12/14/2022]
Abstract
Bitter taste receptors (TAS2Rs) on the tongue probably evolved to evoke signals for avoiding ingestion of plant toxins. We found expression of TAS2Rs on human airway smooth muscle (ASM) and considered these to be avoidance receptors for inhalants that, when activated, lead to ASM contraction and bronchospasm. TAS2R agonists such as saccharin, chloroquine and denatonium evoked increased intracellular calcium ([Ca²(+)](i)) in ASM in a Gβγ-, phospholipase Cβ (PLCβ)- and inositol trisphosphate (IP₃) receptor-dependent manner, which would be expected to evoke contraction. Paradoxically, bitter tastants caused relaxation of isolated ASM and dilation of airways that was threefold greater than that elicited by β-adrenergic receptor agonists. The relaxation induced by TAS2Rs is associated with a localized [Ca²(+)](i) response at the cell membrane, which opens large-conductance Ca²(+)-activated K(+) (BK(Ca)) channels, leading to ASM membrane hyperpolarization. Inhaled bitter tastants decreased airway obstruction in a mouse model of asthma. Given the need for efficacious bronchodilators for treating obstructive lung diseases, this pathway can be exploited for therapy with the thousands of known synthetic and naturally occurring bitter tastants.
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Sbarbati A, Bramanti P, Benati D, Merigo F. The diffuse chemosensory system: exploring the iceberg toward the definition of functional roles. Prog Neurobiol 2010; 91:77-89. [PMID: 20138111 DOI: 10.1016/j.pneurobio.2010.01.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 12/11/2009] [Accepted: 01/27/2010] [Indexed: 01/18/2023]
Abstract
The diffuse chemosensory system (DCS) is an anatomical structure composed of solitary chemosensory cells (SCCs, also called solitary chemoreceptor cells), which have analogies with taste cells but are not aggregated in buds. The concept of DCS has been advanced, after the discovery that cells similar to gustatory elements are present in several organs. The elements forming the DCS share common morphological and biochemical characteristics with the taste cells located in taste buds of the oro-pharyngeal cavity but they are localized in internal organs. In particular, they may express molecules of the chemoreceptorial cascade (e.g. trans-membrane taste receptors, the G-protein alpha-gustducin, PLCbeta2, TRPM5). This article will focus on the mammalian DCS in apparatuses of endodermic origin (i.e. digestive and respiratory systems), which is composed of an enormous number of sensory elements and presents a multiplicity of morphological aspects. Recent research has provided an adequate description of these elements, but the functional role for the DCS in these apparatuses is unknown. The initial findings led to the definition of a DCS structured like an iceberg, with a mysterious "submerged" portion localized in the distal part of endodermic apparatuses. Recent work has focussed on the discovery of this submerged portion, which now appears less puzzling. However, the functional roles of the different cytotypes belonging to the DCS are not well known. Recent studies linked chemosensation of the intraluminal content to local control of absorptive and secretory (exocrine and endocrine) processes. Control of the microbial population and detection of irritants seem to be other possible functions of the DCS. In the light of these new findings, the DCS might be thought to be involved in a wide range of diseases of both the respiratory (e.g. asthma, chronic obstructive pulmonary disease, cystic fibrosis) and digestive apparatuses (absorptive or secretive diseases, dysmicrobism), as well as in systemic diseases (e.g. obesity, diabetes). A description of the functional roles of the DCS might be a first step toward the discovery of therapeutic approaches which target chemosensory mechanisms.
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Affiliation(s)
- Andrea Sbarbati
- Human Anatomy and Histology Section, University of Verona, Medical Faculty, Verona, Italy.
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Nasal chemosensory cells use bitter taste signaling to detect irritants and bacterial signals. Proc Natl Acad Sci U S A 2010; 107:3210-5. [PMID: 20133764 DOI: 10.1073/pnas.0911934107] [Citation(s) in RCA: 308] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The upper respiratory tract is continually assaulted with harmful dusts and xenobiotics carried on the incoming airstream. Detection of such irritants by the trigeminal nerve evokes protective reflexes, including sneezing, apnea, and local neurogenic inflammation of the mucosa. Although free intra-epithelial nerve endings can detect certain lipophilic irritants (e.g., mints, ammonia), the epithelium also houses a population of trigeminally innervated solitary chemosensory cells (SCCs) that express T2R bitter taste receptors along with their downstream signaling components. These SCCs have been postulated to enhance the chemoresponsive capabilities of the trigeminal irritant-detection system. Here we show that transduction by the intranasal solitary chemosensory cells is necessary to evoke trigeminally mediated reflex reactions to some irritants including acyl-homoserine lactone bacterial quorum-sensing molecules, which activate the downstream signaling effectors associated with bitter taste transduction. Isolated nasal chemosensory cells respond to the classic bitter ligand denatonium as well as to the bacterial signals by increasing intracellular Ca(2+). Furthermore, these same substances evoke changes in respiration indicative of trigeminal activation. Genetic ablation of either G alpha-gustducin or TrpM5, essential elements of the T2R transduction cascade, eliminates the trigeminal response. Because acyl-homoserine lactones serve as quorum-sensing molecules for gram-negative pathogenic bacteria, detection of these substances by airway chemoreceptors offers a means by which the airway epithelium may trigger an epithelial inflammatory response before the bacteria reach population densities capable of forming destructive biofilms.
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Ahumedo M, Díaz A, Vivas-Reyes R. Theoretical and structural analysis of the active site of the transcriptional regulators LasR and TraR, using molecular docking methodology for identifying potential analogues of acyl homoserine lactones (AHLs) with anti-quorum sensing activity. Eur J Med Chem 2009; 45:608-15. [PMID: 19945196 DOI: 10.1016/j.ejmech.2009.11.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 11/02/2009] [Indexed: 12/01/2022]
Abstract
In the present study the homology of transcriptional receptors LuxR type were evaluated using as point of reference the receptors TraR and LasR of the bacterial types Agrobacterium tumefaciens and Pseudomonas aureginosa respectively. A series of alignments were performed in order to demonstrate that the active site of the protein is conserved in wide range of gram negative bacteria. Moreover, some docking calculations were carried out for analogs of the acyl homoserin lactones (AHLs) and regulatory proteins LasR and TraR, to understand the complex microenvironment in which the ligands are exposed. The molecular alignments show clearly that there are preserved motifs in the residues (Y53, Y61, W57, D70, W85 to TraR, Y56, Y64, W60, D73, W88 to LasR) analyzed, which may serve as site-specific targets for the development of potential antagonists. In this study was found that the anti-quorum sensing activity of the AHLs molecular analogs appears to depend on; the structure of the lactone ring and on appropriate combination of absolute and relative stereochemistry of the carbonyl (C=O) and amide (NH(2)) groups of the side chain of these AHLs molecular analogs, in combination with the interactions with the conserved amino acids (D73, W60, Y56, S129 to LasR and D70, W57, Y53 to TraR) of the LuxR type protein family.
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Affiliation(s)
- Maicol Ahumedo
- Grupo de Química Cuántica y Teórica, Universidad de Cartagena-Facultad de Ciencias Exactas y, Naturales-Programa de Química, Campus de Zaragocilla-Cartagena, Colombia
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Sbarbati A, Merigo F, Osculati F. Eukaryotic vs. prokaryotic chemosensory systems. Biomed Pharmacother 2009; 64:233-9. [PMID: 20347567 DOI: 10.1016/j.biopha.2009.06.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 06/07/2009] [Indexed: 01/10/2023] Open
Abstract
In the last decades, microbiologists demonstrated that microorganisms possess chemosensory capabilities and communicate with each other via chemical signals. In parallel, it was demonstrated that solitary eukaryotic chemosensory cells are diffusely located on the mucosae of digestive and respiratory apparatuses. It is now evident that on the mucosal surfaces of vertebrates, two chemoreceptorial systems (i.e. eukaryotic and prokaryotic) coexist in a common microenvironment. To date, it is not known if the two chemosensory systems reciprocally interact and compete for detection of chemical cues. This appears to be a fruitful field of study and future researches must consider that the mucosal epithelia possess more chemosensory capabilities than previously supposed.
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Affiliation(s)
- Andrea Sbarbati
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Anatomia ed Istologia, Università di Verona, Strada Le Grazie 8, 37134, Verona, Italy.
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