Publications by authors named "Deepak A Deshpande"

68 Publications

Diacylglycerol Kinase Inhibition Reduces Airway Contraction by Negative Feedback Regulation of Gq-signaling.

Am J Respir Cell Mol Biol 2021 Jul 22. Epub 2021 Jul 22.

Thomas Jefferson University, 6559, Center for Translational Medicine, Philadelphia, Pennsylvania, United States;

Exaggerated airway smooth muscle (ASM) contraction regulated by the Gq family of G protein-coupled receptors (GPCRs) causes airway hyperresponsiveness (AHR) in asthma. Activation of Gq-coupled GPCRs leads to phospholipase C (PLC)-mediated generation of inositol triphosphate (IP3) and diacylglycerol (DAG). DAG signaling is terminated by the action of DAG kinase (DGK) that converts DAG into phosphatidic acid (PA). Our previous study demonstrated that DGKα and ζ isoform knockout mice are protected from the development of allergen-induced AHR. Here we aimed at determining the mechanism by which DGK regulates ASM contraction. Activity of DGK isoforms was inhibited in human ASM cells by siRNA-mediated knockdown of DGKα and ζwhile pharmacological inhibition was achieved by pan DGK inhibitor I (R59022). Effects of DGK inhibition on contractile agonist-induced activation of PLC and myosin light chain (MLC) kinase, elevation of IP3, and calcium levels were assessed. Further, we employed human precision-cut lung slices and assessed the role of DGK in agonist-induced bronchoconstriction. DGK inhibitor I attenuated histamine- and methacholine-induced bronchoconstriction. DGKα and ζ knockdown or pre-treatment with DGK inhibitor I resulted in attenuated agonist-induced phosphorylation of MLC and myosin light chain phosphatase in ASM cells. Further, DGK inhibition decreased Gq agonist-induced calcium elevation, generation of IP3, and increased histamine-induced production of PA. Finally, DGK inhibition or treatment with DAG analog resulted in attenuation of activation of PLC in human ASM cells. Our findings suggest that DGK inhibition perturbed the DAG:PA ratio resulting in inhibition of Gq-PLC activation in a negative feedback manner, resulting in protection against ASM contraction.
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http://dx.doi.org/10.1165/rcmb.2021-0106OCDOI Listing
July 2021

Autocrine regulation of airway smooth muscle contraction by diacylglycerol kinase.

J Cell Physiol 2021 Jul 18. Epub 2021 Jul 18.

Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

Diacylglycerol kinase (DGK), a lipid kinase, catalyzes the conversion of diacylglycerol (DAG) to phosphatidic acid, thereby terminating DAG-mediated signaling by Gq-coupled receptors that regulate contraction of airway smooth muscle (ASM). A previous study from our laboratory demonstrated that DGK inhibition or genetic ablation leads to reduced ASM contraction and provides protection for allergen-induced airway hyperresponsiveness. However, the mechanism by which DGK regulates contractile signaling in ASM is not well established. Herein, we investigated the role of prorelaxant cAMP-protein kinase A (PKA) signaling in DGK-mediated regulation of ASM contraction. Pretreatment of human ASM cells with DGK inhibitor I activated PKA as demonstrated by the phosphorylation of PKA substrates, VASP, Hsp20, and CREB, which was abrogated when PKA was inhibited pharmacologically or molecularly using overexpression of the PKA inhibitor peptide, PKI. Furthermore, inhibition of DGK resulted in induction of cyclooxygenase (COX) and generation of prostaglandin E (PGE ) with concomitant activation of Gs-cAMP-PKA signaling in ASM cells in an autocrine/paracrine fashion. Inhibition of protein kinase C (PKC) or extracellular-signal-regulated kinase (ERK) attenuated DGK-mediated production of PGE and activation of cAMP-PKA signaling in human ASM cells, suggesting that inhibition of DGK activates the COX-PGE pathway in a PKC-ERK-dependent manner. Finally, DGK inhibition-mediated attenuation of contractile agonist-induced phosphorylation of myosin light chain 20 (MLC-20), a marker of ASM contraction, involves COX-mediated cAMP production and PKA activation in ASM cells. Collectively these findings establish a novel mechanism by which DGK regulates ASM contraction and further advances DGK as a potential therapeutic target to provide effective bronchoprotection in asthma.
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http://dx.doi.org/10.1002/jcp.30528DOI Listing
July 2021

Nur77 Attenuates Inflammasome Activation by Inhibiting Caspase-1 Expression in Pulmonary Vascular Endothelial Cells.

Am J Respir Cell Mol Biol 2021 09;65(3):288-299

Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania; and.

Inflammasomes are intracellular multiprotein complexes that help trigger and maintain the inflammatory response as part of the innate immune system. Recently, it has been increasingly recognized that aberrant inflammasome activation is critically involved in endothelial dysfunction in a variety of human diseases, such as atherosclerosis, acute lung injury (ALI), and type 2 diabetes. The molecular mechanisms underlying endothelial inflammasome activation, however, have not been completely elucidated. In the present study, we identified orphan nuclear receptor Nur77 as a novel regulator in controlling inflammasome activation in vascular endothelial cells (ECs). We demonstrated that LPS-induced inflammasome activation was significantly inhibited by ectopic overexpression of Nur77, predominantly through transcriptional suppression of caspase-1 expression in vascular ECs. Consistent with this observation, we found that LPS-induced inflammasome activation was significantly augmented in lung ECs isolated from Nur77-knockout mice. Mechanistically, we showed that Nur77-induced inhibition of caspase-1 expression was due to an inhibition of IRF1 (IFN regulatory factor 1) expression and its subsequent binding to the caspase-1 promoter. Importantly, in a mouse model of LPS-induced ALI, Nur77 knockout led to a marked activation of caspase-1 in the lung, increased alveolar and circulating IL-1β levels, and exacerbated ALI, all of which were substantially inhibited by administration of caspase-1 inhibitor. Together, our results support the presence of an important role for Nur77 in controlling inflammasome activation in vascular ECs and suggest that Nur77 could be a novel therapeutic target for the treatment of human diseases associated with aberrant inflammasome activation, such as ALI and atherosclerosis.
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http://dx.doi.org/10.1165/rcmb.2020-0524OCDOI Listing
September 2021

Chloroquine: Autophagy inhibitor, antimalarial, bitter taste receptor agonist in fight against COVID-19, a reality check?

Eur J Pharmacol 2021 Apr 3;897:173928. Epub 2021 Feb 3.

Center for Translational Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA.

The recent SARS-CoV-2 pandemic poses one of the greatest challenges to modern medicine. Therefore, identification of new therapeutic strategies seems essential either based on novel vaccines or drugs or simply repurposing existing drugs. Notably, due to their known safety profile, repurposing of existing drugs is the fastest and highly efficient approach to bring a therapeutic to a clinic for any new indication. One such drug that has been used extensively for decades is chloroquine (CQ, with its derivatives) either for malaria, lupus and rheumatoid arthritis. Accumulating body of evidence from experimental pharmacology suggests that CQ and related analogues also activate certain pathways that can potentially be exploited for therapeutic gain. For example, in the airways, this has opened an attractive avenue for developing novel bitter taste ligands as a new class of bronchodilators for asthma. While CQ and its derivatives have been proposed as a therapy in COVID-19, it remains to be seen whether it really work in the clinic? To this end, our perspective aims to provide a timely yet brief insights on the existing literature on CQ and the controversies surrounding its use in COVID-19. Further, we also highlight some of cell-based mechanism(s) that CQ and its derivatives affect in mediating variety of physiological responses in the cell. We believe, data emanating from the clinical studies and continual understanding of the fundamental mechanisms may potentially help in designing effective therapeutic strategies that meets both efficacy and safety criteria for COVID-19.
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http://dx.doi.org/10.1016/j.ejphar.2021.173928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857018PMC
April 2021

The odorant receptor OR2W3 on airway smooth muscle evokes bronchodilation via a cooperative chemosensory tradeoff between TMEM16A and CFTR.

Proc Natl Acad Sci U S A 2020 11 23;117(45):28485-28495. Epub 2020 Oct 23.

Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, The State University of New Jersey, Piscataway, NJ 08854;

The recent discovery of sensory (tastant and odorant) G protein-coupled receptors on the smooth muscle of human bronchi suggests unappreciated therapeutic targets in the management of obstructive lung diseases. Here we have characterized the effects of a wide range of volatile odorants on the contractile state of airway smooth muscle (ASM) and uncovered a complex mechanism of odorant-evoked signaling properties that regulate excitation-contraction (E-C) coupling in human ASM cells. Initial studies established multiple odorous molecules capable of increasing intracellular calcium ([Ca]) in ASM cells, some of which were (paradoxically) associated with ASM relaxation. Subsequent studies showed a terpenoid molecule (nerol)-stimulated OR2W3 caused increases in [Ca] and relaxation of ASM cells. Of note, OR2W3-evoked [Ca] mobilization and ASM relaxation required Ca flux through the store-operated calcium entry (SOCE) pathway and accompanied plasma membrane depolarization. This chemosensory odorant receptor response was not mediated by adenylyl cyclase (AC)/cyclic nucleotide-gated (CNG) channels or by protein kinase A (PKA) activity. Instead, ASM olfactory responses to the monoterpene nerol were predominated by the activity of Ca-activated chloride channels (TMEM16A), including the cystic fibrosis transmembrane conductance regulator (CFTR) expressed on endo(sarco)plasmic reticulum. These findings demonstrate compartmentalization of Ca signals dictates the odorant receptor OR2W3-induced ASM relaxation and identify a previously unrecognized E-C coupling mechanism that could be exploited in the development of therapeutics to treat obstructive lung diseases.
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http://dx.doi.org/10.1073/pnas.2003111117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7668088PMC
November 2020

Editorial overview: Pulmonary 2020 - advances in the pharmacology of obstructive lung diseases.

Curr Opin Pharmacol 2020 04;51:iii-vii

Center for Translational Medicine, Department of Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA 19107, USA. Electronic address:

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http://dx.doi.org/10.1016/j.coph.2020.08.016DOI Listing
April 2020

The role of diacylglycerol kinases in allergic airway disease.

Curr Opin Pharmacol 2020 04 21;51:50-58. Epub 2020 Aug 21.

Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA, USA. Electronic address:

Asthma is an obstructive inflammatory airway disease. Airway obstruction is mediated by hyperresponsive airway smooth muscle cell contraction, which is induced and compounded by inflammation caused by T lymphocytes. One important signal transduction pathway that is involved in the activation of these cell types involves the generation of a lipid second messenger known as diacylglycerol (DAG). DAG levels are controlled in cells by a negative regulator known as DAG kinase (DGK). In this review, we discuss how the DAG signaling pathway attenuates the pathological function of immune cells and airway smooth muscle cells in allergic airway disease and asthma. Furthermore, we discuss how the enhancement of the DAG signaling pathway through the inhibition of DGK may represent a novel therapeutic strategy for these diseases.
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http://dx.doi.org/10.1016/j.coph.2020.07.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530135PMC
April 2020

Therapeutic potential and challenges of bitter taste receptors on lung cells.

Curr Opin Pharmacol 2020 04 15;51:43-49. Epub 2020 Aug 15.

Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA 19107, United States. Electronic address:

Airway smooth muscle (ASM) hyperresponsiveness and airway remodeling are pathological drivers of disease progression and mortality in asthma. Importantly, approximately 50% of affected individuals are unable to reliably manage disease symptoms using the current standard of care. Recently, T2Rs have been identified as a novel class of G protein-coupled receptors expressed in the airway that on activation can induce ASM relaxation and reduction in airway tone. Further, agonists of T2Rs may also remedy airway remodeling, which has been difficult to manage with currently available medications. In this review, we will discuss the recent developments in T2R biology and their role in cellular physiology (particularly ASM) and expand on the therapeutic potential of T2R agonists in treatment of asthma.
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http://dx.doi.org/10.1016/j.coph.2020.07.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530014PMC
April 2020

Role of CD38/cADPR signaling in obstructive pulmonary diseases.

Curr Opin Pharmacol 2020 04 29;51:29-33. Epub 2020 May 29.

Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States.

The worldwide socioeconomical burden associated with chronic respiratory diseases is substantial. Enzymes involved in the metabolism of nicotinamide adenine dinucleotide (NAD) are increasingly being implicated in chronic airway diseases. One such enzyme, CD38, utilizes NAD to produce several metabolites, including cyclic ADP ribose (cADPR), which is involved in calcium signaling in airway smooth muscle (ASM). Upregulation of CD38 in ASM caused by exposure to cytokines or allergens leads to enhanced calcium mobilization by agonists and the development of airway hyperresponsiveness (AHR) to contractile agonists. Glucocorticoids and microRNAs can suppress CD38 expression in ASM, whereas cADPR antagonists such as 8Br-cADPR can directly antagonize intracellular calcium mobilization. Bronchodilators act via CD38-independent mechanisms. CD38-dependent mechanisms could be developed for chronic airway diseases therapy.
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http://dx.doi.org/10.1016/j.coph.2020.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7529733PMC
April 2020

A tripartite cooperative mechanism confers resistance of the protein kinase A catalytic subunit to dephosphorylation.

J Biol Chem 2020 03 21;295(10):3316-3329. Epub 2020 Jan 21.

Center for Translational Medicine and Korman Respiratory Institute, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.

Phosphorylation of specific residues in the activation loops of AGC kinase group (protein kinase A, G, and C families) is required for activity of most of these kinases, including the catalytic subunit of PKA (PKAc). Although many phosphorylated AGC kinases are sensitive to phosphatase-mediated dephosphorylation, the PKAc activation loop uniquely resists dephosphorylation, rendering it "constitutively" phosphorylated in cells. Previous biophysical experiments and structural modeling have suggested that the N-terminal myristoylation signal and the C-terminal FF motif in PKAc regulate its thermal stability and catalysis. Here, using site-directed mutagenesis, molecular modeling, and in cell-free and cell-based systems, we demonstrate that substitutions of either the PKAc myristoylation signal or the FF motif only modestly reduce phosphorylation and fail to affect PKAc function in cells. However, we observed that these two sites cooperate with an N-terminal FW motif to cooperatively establish phosphatase resistance of PKAc while not affecting kinase-dependent phosphorylation of the activation loop. We noted that this tripartite cooperative mechanism of phosphatase resistance is functionally relevant, as demonstrated by changes in morphology, adhesion, and migration of human airway smooth muscle cells transfected with PKAc variants containing amino acid substitutions in these three sites. These findings establish that three allosteric sites located at the PKAc N and C termini coordinately regulate the phosphatase sensitivity of this enzyme. This cooperative mechanism of phosphatase resistance of AGC kinase opens new perspectives toward therapeutic manipulation of kinase signaling in disease.
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http://dx.doi.org/10.1074/jbc.RA119.010004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062156PMC
March 2020

Reply to Letter to the Editor: "Bnip3 as a potential target to treat airway smooth muscle remodeling in asthma?"

Am J Physiol Lung Cell Mol Physiol 2020 01;318(1):L213-L214

Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania.

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http://dx.doi.org/10.1152/ajplung.00470.2019DOI Listing
January 2020

Increased expression of desmin and vimentin reduces bladder smooth muscle contractility via JNK2.

FASEB J 2020 02 16;34(2):2126-2146. Epub 2019 Dec 16.

Department of Medicine, Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA, USA.

Bladder dysfunction is associated with the overexpression of the intermediate filament (IF) proteins desmin and vimentin in obstructed bladder smooth muscle (BSM). However, the mechanisms by which these proteins contribute to BSM dysfunction are not known. Previous studies have shown that desmin and vimentin directly participate in signal transduction. In this study, we hypothesized that BSM dysfunction associated with overexpression of desmin or vimentin is mediated via c-Jun N-terminal kinase (JNK). We employed a model of murine BSM tissue in which increased expression of desmin or vimentin was induced by adenoviral transduction to examine the sufficiency of increased IF protein expression to reduce BSM contraction. Murine BSM strips overexpressing desmin or vimentin generated less force in response to KCl and carbachol relative to the levels in control murine BSM strips, an effect associated with increased JNK2 phosphorylation and reduced myosin light chain (MLC ) phosphorylation. Furthermore, desmin and vimentin overexpressions did not alter BSM contractility and MLC phosphorylation in strips isolated from JNK2 knockout mice. Pharmacological JNK2 inhibition produced results qualitatively similar to those caused by JNK2 knockout. These findings suggest that inhibition of JNK2 may improve diminished BSM contractility associated with obstructive bladder disease.
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http://dx.doi.org/10.1096/fj.201901301RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7018560PMC
February 2020

Bnip3 regulates airway smooth muscle cell focal adhesion and proliferation.

Am J Physiol Lung Cell Mol Physiol 2019 12 11;317(6):L758-L767. Epub 2019 Sep 11.

Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania.

Increased airway smooth muscle (ASM) mass is a key contributor to airway narrowing and airway hyperresponsiveness in asthma. Besides conventional pathways and regulators of ASM proliferation, recent studies suggest that changes in mitochondrial morphology and function play a role in airway remodeling in asthma. In this study, we aimed at determining the role of mitochondrial Bcl-2 adenovirus E1B 19 kDa-interacting protein, Bnip3, in the regulation of ASM proliferation. Bnip3 is a member of the Bcl-2 family of proteins critical for mitochondrial health, mitophagy, and cell survival/death. We found that Bnip3 expression is upregulated in ASM cells from asthmatic donors compared with that in ASM cells from healthy donors and transient downregulation of Bnip3 expression in primary human ASM cells using an siRNA approach decreased cell adhesion, migration, and proliferation. Furthermore, Bnip3 downregulation altered the structure (electron density) and function (cellular ATP levels, membrane potential, and reacitve oxygen species generation) of mitochondria and decreased expression of cytoskeleton proteins vinculin, paxillin, and actinin. These findings suggest that Bnip3 via regulation of mitochondria functions and expression of adhesion proteins regulates ASM adhesion, migration, and proliferation. This study reveals a novel role for Bnip3 in ASM functions and establishes Bnip3 as a potential target in mitigating ASM remodeling in asthma.
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http://dx.doi.org/10.1152/ajplung.00224.2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957365PMC
December 2019

Bitter Taste Receptors: an Answer to Comprehensive Asthma Control?

Curr Allergy Asthma Rep 2019 09 5;19(10):48. Epub 2019 Sep 5.

Department of Medicine, Center for Translational Medicine and Division of Pulmonary, Allergy and Critical Care Medicine; and Jane & Leonard Korman Respiratory Institute, Thomas Jefferson University, Jefferson Alumni Hall, Room 543, 1020 Locust Street, Philadelphia, PA, 19107, USA.

Purpose Of Review: Asthma is marked by peculiar pathological features involving airway contraction, an impinging inflammation in the lungs, and an inexorably progressive remodeling of pulmonary architecture. Current medications for management of asthma exacerbations fail to optimally mitigate these pathologies, which is partly due to the intrinsic heterogeneity in the development and progression of asthma within different populations. In recent years, the discovery of the ectopic expression of TAS2Rs in extraoral tissues and different cell types, combined with significant strides in gaining mechanistic understanding into receptor signaling and function, has revealed the potential to target TAS2Rs for asthma relief.

Recent Findings: TAS2R activation leads to relaxation of airway smooth muscle cells and bronchodilation. In addition, findings from preclinical studies in murine model of asthma suggest that TAS2R agonists inhibit allergen-induced airway inflammation, remodeling, and hyperresponsiveness. In this review, we expand on the opportunity presented by TAS2Rs in the development of a comprehensive asthma treatment that overcomes the limitations set forth by current asthma therapeutics.
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http://dx.doi.org/10.1007/s11882-019-0876-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6765386PMC
September 2019

Diacylglycerol kinase ζ promotes allergic airway inflammation and airway hyperresponsiveness through distinct mechanisms.

Sci Signal 2019 09 3;12(597). Epub 2019 Sep 3.

Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.

Asthma is a chronic allergic inflammatory airway disease caused by aberrant immune responses to inhaled allergens, which leads to airway hyperresponsiveness (AHR) to contractile stimuli and airway obstruction. Blocking T helper 2 (T2) differentiation represents a viable therapeutic strategy for allergic asthma, and strong TCR-mediated ERK activation blocks T2 differentiation. Here, we report that targeting diacylglycerol (DAG) kinase zeta (DGKζ), a negative regulator of DAG-mediated cell signaling, protected against allergic asthma by simultaneously reducing airway inflammation and AHR though independent mechanisms. Targeted deletion of DGKζ in T cells decreased type 2 inflammation without reducing AHR. In contrast, loss of DGKζ in airway smooth muscle cells decreased AHR but not airway inflammation. T cell-specific enhancement of ERK signaling was only sufficient to limit type 2 airway inflammation, not AHR. Pharmacological inhibition of DGK diminished both airway inflammation and AHR in mice and also reduced bronchoconstriction of human airway samples in vitro. These data suggest that DGK is a previously unrecognized therapeutic target for asthma and reveal that the inflammatory and AHR components of asthma are not as interdependent as generally believed.
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http://dx.doi.org/10.1126/scisignal.aax3332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6996596PMC
September 2019

Bitter Taste Receptors for Asthma Therapeutics.

Front Physiol 2019 16;10:884. Epub 2019 Jul 16.

Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Medicine, Department of Medicine, Jane and Leonard Korman Respiratory Institute, Thomas Jefferson University, Philadelphia, PA, United States.

Clinical management of asthma and chronic obstructive pulmonary disease (COPD) has primarily relied on the use of beta 2 adrenergic receptor agonists (bronchodilators) and corticosteroids, and more recently, monoclonal antibody therapies (biologics) targeting specific cytokines and their functions. Although these approaches provide relief from exacerbations, questions remain on their long-term efficacy and safety. Furthermore, current therapeutics do not address progressive airway remodeling (AR), a key pathological feature of severe obstructive lung disease. Strikingly, agonists of the bitter taste receptors (TAS2Rs) deliver robust bronchodilation, curtail allergen-induced inflammatory responses in the airways and regulate airway smooth muscle (ASM) cell proliferation and mitigate features of AR and in animal models. The scope of this review is to provide a comprehensive and systematic insight into our current understanding of TAS2Rs with an emphasis on the molecular events that ensue TAS2R activation in distinct airway cell types and expand on the pleiotropic effects of TAS2R targeting in mitigating various pathological features of obstructive lung diseases. Finally, we will discuss specific opportunities that could help the development of selective agonists for specific TAS2R subtypes in the treatment of asthma.
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http://dx.doi.org/10.3389/fphys.2019.00884DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6647873PMC
July 2019

Effects of ATP-competitive and function-selective ERK inhibitors on airway smooth muscle cell proliferation.

FASEB J 2019 10 26;33(10):10833-10843. Epub 2019 Jul 26.

Department of Medicine, Jefferson University, Philadelphia, Pennsylvania, USA.

Increased airway smooth muscle (ASM) cell mass and secretory functions are characteristics of airway inflammatory diseases, such as asthma. To date, there are no effective therapies to combat ASM cell proliferation, which contributes to bronchoconstriction and airway obstruction. Growth factors such as platelet-derived growth factor (PDGF) and the activation of the ERK1/2 are major regulators of ASM cell proliferation and airway remodeling in asthma. However, given the ubiquitous expression and multiple functions of ERK1/2, complete inhibition of ERK1/2 using ATP-competitive inhibitors may lead to unwanted off-target effects. Alternatively, we have identified compounds that are designed to target substrate docking sites and act as function-selective inhibitors of ERK1/2 signaling. Here, we show that both function-selective and ATP-competitive ERK1/2 inhibitors are effective at inhibiting PDGF-mediated proliferation, collagen production, and IL-6 secretion in ASM cells. Proteomic analysis revealed that both types of inhibitors had similar effects on reducing proteins related to TGF-β and IL-6 signaling that are relevant to airway remodeling. However, function-selective ERK1/2 inhibitors caused fewer changes in protein expression compared with ATP-competitive inhibitors. These studies provide a molecular basis for the development of function-selective ERK1/2 inhibitors to mitigate airway remodeling in asthma with defined regulation of ERK1/2 signaling.-Defnet, A. E., Huang, W., Polischak, S., Yadav, S. K., Kane, M. A., Shapiro, P., Deshpande, D. A. Effects of ATP-competitive and function-selective ERK inhibitors on airway smooth muscle cell proliferation.
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http://dx.doi.org/10.1096/fj.201900680RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766654PMC
October 2019

Specificity of NHERF1 regulation of GPCR signaling and function in human airway smooth muscle.

FASEB J 2019 08 1;33(8):9008-9016. Epub 2019 May 1.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Center for Translational Medicine, The Jane and Leonard Korman Respiratory Institute, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

Na/H exchanger regulatory factor 1 (NHERF1; also known as ezrin-radixin-moesin-binding phosphoprotein 50) is a PSD-95, disc large, zona occludens-1 adapter that acts as a scaffold for signaling complexes and cytoskeletal-plasma membrane interactions. NHERF1 is crucial to β-2-adrenoceptor (βAR)-mediated activation of cystic fibrosis transmembrane conductance regulator (CFTR) in epithelial cells, and NHERF1 has been proposed to mediate the recycling of internalized βAR back to the cell membrane. In the current study, we assessed the role of NHERF1 in regulating cAMP-mediated signaling and immunomodulatory functions in airway smooth muscle (ASM). NHERF1 knockdown attenuated the induction of (protein kinase A) phospho-vasodilator-stimulated phosphoprotein (p-VASP) by isoproterenol (ISO), prostaglandin E (PGE), or forskolin (FSK) as well as the induction of p-heat shock protein 20 after 4 h of stimulation with ISO and FSK. NHERF1 knockdown fully abrogated the ISO-, PGE-, and FSK-induced IL-6 gene expression and cytokine production without affecting cAMP-mediated phosphodiesterase 4D (PDE4D) gene expression, phospho-cAMP response element-binding protein (p-CREB), and cAMP response element (CRE)-Luc, or PDGF-induced cyclin D1 expression. Interestingly, NHERF1 knockdown prevented ISO-induced chromatin-binding of the transcription factor CCAAT-enhancer-binding protein-β (c/EBPβ). c/EBPβ knockdown almost completely abrogated the cAMP-mediated IL-6 but not PDE4D gene expression. The differential regulation of cAMP-induced signaling and gene expression in our study indicates a role for NHERF1 in the compartmentalization of cAMP signaling in ASM.-Pera, T., Tompkins, E., Katz, M., Wang, B., Deshpande, D. A., Weinman, E. J., Penn, R. B. Specificity of NHERF1 regulation of GPCR signaling and function in human airway smooth muscle.
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http://dx.doi.org/10.1096/fj.201900323RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6662985PMC
August 2019

Regulation of ovarian cancer G protein-coupled receptor-1 expression and signaling.

Am J Physiol Lung Cell Mol Physiol 2019 05 6;316(5):L894-L902. Epub 2019 Feb 6.

Department of Medicine, Center for Translational Medicine and Division of Pulmonary, Allergy and Critical Care Medicine; and Jane & Leonard Korman Respiratory Institute, Thomas Jefferson University, Philadelphia, Pennsylvania.

Ovarian cancer G protein-coupled receptor 1 (OGR1) is a recently deorphanized G protein-coupled receptor shown to signal in response to low extracellular pH (↓pH) or certain benzodiazepines. The pleiotropic nature of OGR1 signaling in human airway smooth muscle (HASM) cells suggests that OGR1 is a potential therapeutic target for the management of obstructive lung diseases. However, the basic pharmacological and regulatory features of OGR1 remain poorly understood. We employed model systems of heterologously expressed [human embryonic kidney 293 (HEK293) cells] or endogenous (HASM) OGR1 to assess changes in expression, subcellular localization, and signaling capabilities following acute or chronic treatment with ↓pH or the benzodiazepines lorazepam and sulazepam. In HEK293 cells expressing OGR1, treatment with ↓pH and/or lorazepam, but not sulazepam, caused rapid OGR1 internalization. In HASM cells, acute treatment with ↓pH or benzodiazepines did not alter abundance of OGR1 mRNA; however, significant downregulation was observed following chronic treatment. Acute and chronic pretreatment of HASM cells with sulazepam or lorazepam resulted in receptor desensitization as demonstrated by reduced phosphorylation of vasodilator-stimulated phosphoprotein (VASP) or p42/p44 upon rechallenge. Acid (acute but not chronic) pretreatment of HASM cells induced desensitization of OGR1-mediated VASP (but not p42/p44) phosphorylation. In contrast to a recent study reporting OGR1 upregulation and sensitization in cardiac tissue subject to ischemic/acidic insult, chronic OGR1 activation in multiple model systems did not increase OGR1 expression or signaling capacity. The ability to induce OGR1 internalization and desensitization was activator dependent, reflecting the ability of different activators to induce specific receptor confirmations and engagement of specific heterotrimeric G proteins.
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http://dx.doi.org/10.1152/ajplung.00426.2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6589584PMC
May 2019

NF-κB and GATA-Binding Factor 6 Repress Transcription of Caveolins in Bladder Smooth Muscle Hypertrophy.

Am J Pathol 2019 04 30;189(4):847-867. Epub 2019 Jan 30.

Department of Medicine, Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania; Division of Urology, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Caveolins (CAVs) are structural proteins of caveolae that function as signaling platforms to regulate smooth muscle contraction. Loss of CAV protein expression is associated with impaired contraction in obstruction-induced bladder smooth muscle (BSM) hypertrophy. In this study, microarray analysis of bladder RNA revealed down-regulation of CAV1, CAV2, and CAV3 gene transcription in BSM from models of obstructive bladder disease in mice and humans. We identified and characterized regulatory regions responsible for CAV1, CAV2, and CAV3 gene expression in mice with obstruction-induced BSM hypertrophy, and in men with benign prostatic hyperplasia. DNA affinity chromatography and chromatin immunoprecipitation assays revealed a greater increase in binding of GATA-binding factor 6 (GATA-6) and NF-κB to their cognate binding motifs on CAV1, CAV2, and CAV3 promoters in obstructed BSM relative to that observed in control BSM. Knockout of NF-κB subunits, shRNA-mediated knockdown of GATA-6, or pharmacologic inhibition of GATA-6 and NF-κB in BSM increased CAV1, CAV2, and CAV3 transcription and promoter activity. Conversely, overexpression of GATA-6 decreased CAV2 and CAV3 transcription and promoter activity. Collectively, these data provide new insight into the mechanisms by which CAV gene expression is repressed in hypertrophied BSM in obstructive bladder disease.
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http://dx.doi.org/10.1016/j.ajpath.2018.12.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6458544PMC
April 2019

Mitochondrial regulation of airway smooth muscle functions in health and pulmonary diseases.

Arch Biochem Biophys 2019 03 8;663:109-119. Epub 2019 Jan 8.

Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA. Electronic address:

Mitochondria are important for airway smooth muscle physiology due to their diverse yet interconnected roles in calcium handling, redox regulation, and cellular bioenergetics. Increasing evidence indicates that mitochondria dysfunction is intimately associated with airway diseases such as asthma, IPF and COPD. In these pathological conditions, increased mitochondrial ROS, altered bioenergetics profiles, and calcium mishandling contribute collectively to changes in cellular signaling, gene expression, and ultimately changes in airway smooth muscle contractile/proliferative properties. Therefore, understanding the basic features of airway smooth muscle mitochondria and their functional contribution to airway biology and pathology are key to developing novel therapeutics for airway diseases. This review summarizes the recent findings of airway smooth muscle mitochondria focusing on calcium homeostasis and redox regulation, two key determinants of physiological and pathological functions of airway smooth muscle.
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http://dx.doi.org/10.1016/j.abb.2019.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377851PMC
March 2019

Cooperativity of E-prostanoid receptor subtypes in regulating signaling and growth inhibition in human airway smooth muscle.

FASEB J 2019 04 2;33(4):4780-4789. Epub 2019 Jan 2.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

Prostaglandin E2 (PGE) is produced in the airway during allergic lung inflammation and both promotes and inhibits features of asthma pathology. These mixed effects relate to 4 E-prostanoid (EP) receptor subtypes (EP1, 2, 3 and 4) expressed at different levels on different resident and infiltrating airway cells. Although studies have asserted both EP2 and EP4 expression in human airway smooth muscle (HASM), a recent study asserted EP4 to be the functionally dominant EP subtype in HASM. Herein, we employ recently-developed subtype-selective ligands to investigate singular or combined EP2 and EP4 receptor activation in regulating HASM signaling and proliferation. The subtype specificity of ONO-AE1-259-01 (EP2 agonist) and ONO-AE1-329 (EP4 agonist) was first demonstrated in human embryonic kidney 293 cells stably expressing different EP receptor subtypes. EP receptor knockdown and subtype-selective antagonists demonstrated EP2 and EP4 receptor responsiveness in HASM cells to the specific ONO compounds, whereas PGE appeared to preferentially signal via the EP4 receptor. Both singular EP2 and EP4 receptor agonists inhibited HASM proliferation, and combined EP2 and EP4 receptor agonism exhibited positive cooperativity in both chronic G-mediated signaling and inhibiting HASM proliferation. These findings suggest both EP2 and EP4 are functionally important in HASM, and their combined targeting optimally inhibits airway smooth muscle proliferation.-Michael, J. V. Gavrila, A., Nayak, A. P., Pera, T., Liberato, J. R., Polischak, S. R., Shah, S. D., Deshpande, D. A., Penn, R. B. Cooperativity of E-prostanoid receptor subtypes in regulating signaling and growth inhibition in human airway smooth muscle.
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http://dx.doi.org/10.1096/fj.201801959RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6436661PMC
April 2019

Autophagy Activation in Asthma Airways Remodeling.

Am J Respir Cell Mol Biol 2019 05;60(5):541-553

3 School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia.

Current asthma therapies fail to target airway remodeling that correlates with asthma severity driving disease progression that ultimately leads to loss of lung function. Macroautophagy (hereinafter "autophagy") is a fundamental cell-recycling mechanism in all eukaryotic cells; emerging evidence suggests that it is dysregulated in asthma. We investigated the interrelationship between autophagy and airway remodeling and assessed preclinical efficacy of a known autophagy inhibitor in murine models of asthma. Human asthmatic and nonasthmatic lung tissues were histologically evaluated and were immunostained for key autophagy markers. The percentage area of positive staining was quantified in the epithelium and airway smooth muscle bundles using ImageJ software. Furthermore, the autophagy inhibitor chloroquine was tested intranasally in prophylactic (3 wk) and treatment (5 wk) models of allergic asthma in mice. Human asthmatic tissues showed greater tissue inflammation and demonstrated hallmark features of airway remodeling, displaying thickened epithelium ( < 0.001) and reticular basement membrane ( < 0.0001), greater lamina propria depth ( < 0.005), and increased airway smooth muscle bundles ( < 0.001) with higher expression of Beclin-1 ( < 0.01) and ATG5 (autophagy-related gene 5) ( < 0.05) together with reduced p62 ( < 0.05) compared with nonasthmatic control tissues. Beclin-1 expression was significantly higher in asthmatic epithelium and ciliated cells ( < 0.05), suggesting a potential role of ciliophagy in asthma. Murine asthma models demonstrated effective preclinical efficacy (reduced key features of allergic asthma: airway inflammation, airway hyperresponsiveness, and airway remodeling) of the autophagy inhibitor chloroquine. Our data demonstrate cell context-dependent and selective activation of autophagy in structural cells in asthma. Furthermore, this pathway can be effectively targeted to ameliorate airway remodeling in asthma.
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http://dx.doi.org/10.1165/rcmb.2018-0169OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503620PMC
May 2019

Apoptosis signal-regulating kinase 1 inhibition attenuates human airway smooth muscle growth and migration in chronic obstructive pulmonary disease.

Clin Sci (Lond) 2018 07 31;132(14):1615-1627. Epub 2018 Jul 31.

Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW 2037, Australia

Increased airway smooth muscle (ASM) mass is observed in chronic obstructive pulmonary disease (COPD), which is correlated with disease severity and negatively affects lung function in these patients. Thus, there is clear unmet clinical need for finding new therapies which can target airway remodeling and disease progression in COPD. Apoptosis signal-regulating kinase 1 (ASK1) is a ubiquitously expressed mitogen-activated protein kinase (MAPK) kinase kinase (MAP3K) activated by various stress stimuli, including reactive oxygen species (ROS), tumor necrosis factor (TNF)-α, and lipopolysaccharide (LPS) and is known to regulate cell proliferation. ASM cells from COPD patients are hyperproliferative to mitogens However, the role of ASK1 in ASM growth is not established. Here, we aim to determine the effects of ASK1 inhibition on ASM growth and pro-mitogenic signaling using ASM cells from COPD patients. We found greater expression of ASK1 in ASM bundles of COPD lung when compared with non-COPD. Pre-treatment of ASM cells with highly selective ASK1 inhibitor, TC ASK 10 resulted in a dose-dependent reduction in mitogen (FBS, PDGF, and EGF; 72 h)-induced ASM growth as measured by CyQUANT assay. Further, molecular targetting of ASK1 using siRNA in ASM cells prevented mitogen-induced cell growth. In addition, to anti-mitogenic potential, ASK1 inhibitor also prevented TGFβ1-induced migration of ASM cells Immunoblotting revealed that anti-mitogenic effects are mediated by C-Jun N-terminal kinase (JNK) and p38MAP kinase-signaling pathways as evident by reduced phosphorylation of downstream effectors JNK1/2 and p38MAP kinases, respectively, with no effect on extracellular signal-regulated kinase (ERK) 1/2 (ERK1/2). Collectively, these findings establish the anti-mitogenic effect of ASK1 inhibition and identify a novel pathway that can be targetted to reduce or prevent excessive ASM mass in COPD.
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http://dx.doi.org/10.1042/CS20180398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6218165PMC
July 2018

New targets for resolution of airway remodeling in obstructive lung diseases.

F1000Res 2018 30;7. Epub 2018 May 30.

Center for Translational Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, USA.

Airway remodeling (AR) is a progressive pathological feature of the obstructive lung diseases, including asthma and chronic obstructive pulmonary disease (COPD). The pathology manifests itself in the form of significant, progressive, and (to date) seemingly irreversible changes to distinct respiratory structural compartments. Consequently, AR correlates with disease severity and the gradual decline in pulmonary function associated with asthma and COPD. Although current asthma/COPD drugs manage airway contraction and inflammation, none of these effectively prevent or reverse features of AR. In this review, we provide a brief overview of the features and putative mechanisms affecting AR. We further discuss recently proposed strategies with promise for deterring or treating AR.
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http://dx.doi.org/10.12688/f1000research.14581.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981194PMC
May 2018

Improvement in Therapeutic Efficacy and Reduction in Cellular Toxicity: Introduction of a Novel Anti-PSMA-Conjugated Hybrid Antiandrogen Nanoparticle.

Mol Pharm 2018 05 4;15(5):1778-1790. Epub 2018 Apr 4.

Second generation antiandrogens have improved overall survival for men with metastatic castrate resistant prostate cancer; however, the antiandrogens result in suppression of androgen receptor (AR) activity in all tissues resulting in dose limiting toxicity. We sought to overcome this limitation through encapsulation in a prostate specific membrane antigen (PSMA)-conjugated nanoparticle. We designed and characterized a novel nanoparticle containing an antiandrogen, enzalutamide. Selectivity and enhanced efficacy was achieved through coating the particle with PSMA. The PSMA-conjugated nanoparticle was internalized selectively in AR expressing prostate cancer cells. It did not elicit an inflammatory effect. The efficacy of enzalutamide was not compromised through insertion into the nanoparticle; in fact, lower systemic drug concentrations of enzalutamide resulted in comparable clinical activity. Normal muscle cells were not impacted by the PSMA-conjugated containing antiandrogen. This approach represents a novel strategy to increase the specificity and effectiveness of antiandrogen treatment for men with castrate resistant prostate cancer. The ability to deliver higher drug concentrations in prostate cancer cells may translate into improved clinical end points including overall survival.
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http://dx.doi.org/10.1021/acs.molpharmaceut.7b01024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6526938PMC
May 2018

CD38/cADPR Signaling Pathway in Airway Disease: Regulatory Mechanisms.

Mediators Inflamm 2018 7;2018:8942042. Epub 2018 Feb 7.

Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA.

Asthma is an inflammatory disease in which proinflammatory cytokines have a role in inducing abnormalities of airway smooth muscle function and in the development of airway hyperresponsiveness. Inflammatory cytokines alter calcium (Ca) signaling and contractility of airway smooth muscle, which results in nonspecific airway hyperresponsiveness to agonists. In this context, Ca regulatory mechanisms in airway smooth muscle and changes in these regulatory mechanisms encompass a major component of airway hyperresponsiveness. Although dynamic Ca regulation is complex, phospholipase C/inositol tris-phosphate (PLC/IP3) and CD38-cyclic ADP-ribose (CD38/cADPR) are two major pathways mediating agonist-induced Ca regulation in airway smooth muscle. Altered CD38 expression or enhanced cyclic ADP-ribosyl cyclase activity associated with CD38 contributes to human pathologies such as asthma, neoplasia, and neuroimmune diseases. This review is focused on investigations on the role of CD38-cyclic ADP-ribose signaling in airway smooth muscle in the context of transcriptional and posttranscriptional regulation of CD38 expression. The specific roles of transcription factors NF-kB and AP-1 in the transcriptional regulation of CD38 expression and of miRNAs miR-140-3p and miR-708 in the posttranscriptional regulation and the underlying mechanisms of such regulation are discussed.
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http://dx.doi.org/10.1155/2018/8942042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821947PMC
September 2018

Biased signaling of the proton-sensing receptor OGR1 by benzodiazepines.

FASEB J 2018 02 4;32(2):862-874. Epub 2018 Jan 4.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

GPCRs have diverse signaling capabilities, based on their ability to assume various conformations. Moreover, it is now appreciated that certain ligands can promote distinct receptor conformations and thereby bias signaling toward a specific pathway to differentially affect cell function. The recently deorphanized G protein-coupled receptor OGR1 [ovarian cancer G protein-coupled receptor 1 ( GPR68)] exhibits diverse signaling events when stimulated by reductions in extracellular pH. We recently demonstrated airway smooth muscle cells transduce multiple signaling events, reflecting a diverse capacity to couple to multiple G proteins. Moreover, we recently discovered that the benzodiazepine lorazepam, more commonly recognized as an agonist of the γ-aminobutyric acid A (GABA) receptor, can function as an allosteric modulator of OGR1 and, similarly, can promote multiple signaling events. In this study, we demonstrated that different benzodiazepines exhibit a range of biases for OGR1, with sulazepam selectively activating the canonical Gs of the G protein signaling pathway, in heterologous expression systems, as well as in several primary cell types. These findings highlight the potential power of biased ligand pharmacology for manipulating receptor signaling qualitatively, to preferentially activate pathways that are therapeutically beneficial.-Pera, T., Deshpande, D. A., Ippolito, M., Wang, B., Gavrila, A., Michael, J. V., Nayak, A. P., Tompkins, E., Farrell, E., Kroeze, W. K., Roth, B. L., Panettieri, R. A. Jr Benovic, J. L., An, S. S., Dulin, N. O., Penn, R. B. Biased signaling of the proton-sensing receptor OGR1 by benzodiazepines.
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http://dx.doi.org/10.1096/fj.201700555RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5888400PMC
February 2018

Bitter taste receptor agonists alter mitochondrial function and induce autophagy in airway smooth muscle cells.

Am J Physiol Lung Cell Mol Physiol 2017 07 27;313(1):L154-L165. Epub 2017 Apr 27.

Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania

Airway remodeling, including increased airway smooth muscle (ASM) mass, is a hallmark feature of asthma and COPD. We previously identified the expression of bitter taste receptors (TAS2Rs) on human ASM cells and demonstrated that known TAS2R agonists could promote ASM relaxation and bronchodilation and inhibit mitogen-induced ASM growth. In this study, we explored cellular mechanisms mediating the antimitogenic effect of TAS2R agonists on human ASM cells. Pretreatment of ASM cells with TAS2R agonists chloroquine and quinine resulted in inhibition of cell survival, which was largely reversed by bafilomycin A1, an autophagy inhibitor. Transmission electron microscope studies demonstrated the presence of double-membrane autophagosomes and deformed mitochondria. In ASM cells, TAS2R agonists decreased mitochondrial membrane potential and increased mitochondrial ROS and mitochondrial fragmentation. Inhibiting dynamin-like protein 1 (DLP1) reversed TAS2R agonist-induced mitochondrial membrane potential change and attenuated mitochondrial fragmentation and cell death. Furthermore, the expression of mitochondrial protein BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) and mitochondrial localization of DLP1 were significantly upregulated by TAS2R agonists. More importantly, inhibiting Bnip3 mitochondrial localization by dominant-negative Bnip3 significantly attenuated cell death induced by TAS2R agonist. Collectively the TAS2R agonists chloroquine and quinine modulate mitochondrial structure and function, resulting in ASM cell death. Furthermore, Bnip3 plays a central role in TAS2R agonist-induced ASM functional changes via a mitochondrial pathway. These findings further establish the cellular mechanisms of antimitogenic effects of TAS2R agonists and identify a novel class of receptors and pathways that can be targeted to mitigate airway remodeling as well as bronchoconstriction in obstructive airway diseases.
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http://dx.doi.org/10.1152/ajplung.00106.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538869PMC
July 2017

Bitter Taste Receptor Agonists Mitigate Features of Allergic Asthma in Mice.

Sci Rep 2017 04 11;7:46166. Epub 2017 Apr 11.

Department of Medicine, Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA.

Asthma is characterized by airway inflammation, mucus secretion, remodeling and hyperresponsiveness (AHR). Recent research has established the bronchodilatory effect of bitter taste receptor (TAS2R) agonists in various models. Comprehensive pre-clinical studies aimed at establishing effectiveness of TAS2R agonists in disease models are lacking. Here we aimed to determine the effect of TAS2R agonists on features of asthma. Further, we elucidated a mechanism by which TAS2R agonists mitigate features of asthma. Asthma was induced in mice using intranasal house dust mite or aerosol ova-albumin challenge, and chloroquine or quinine were tested in both prophylactic and treatment models. Allergen challenge resulted in airway inflammation as evidenced by increased immune cells infiltration and release of cytokines and chemokines in the lungs, which were significantly attenuated in TAS2R agonists treated mice. TAS2R agonists attenuated features of airway remodeling including smooth muscle mass, extracellular matrix deposition and pro-fibrotic signaling, and also prevented mucus accumulation and development of AHR in mice. Mechanistic studies using human neutrophils demonstrated that inhibition of immune cell chemotaxis is a key mechanism by which TAS2R agonists blocked allergic airway inflammation and exerted anti-asthma effects. Our comprehensive studies establish the effectiveness of TAS2R agonists in mitigating multiple features of allergic asthma.
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http://dx.doi.org/10.1038/srep46166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5387415PMC
April 2017
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