TAS2R Agonists Research Articles

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

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.

Bitter Taste Receptor Agonists Mitigate Features of Allergic Asthma in Mice

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.

The expression of bitter taste receptors in mesenteric, cerebral and omental arteries

AimBitter taste is sensed by the bitter taste receptor (TAS2R), which is mainly expressed in the tongue as well as in extra-oral organs, such as the gastrointestinal tract, respiratory tract, brain, heart and testis. This study aimed to investigate whether TAS2R is expressed in the mesenteric, cerebral and omental arteries. Main methodsThe expression levels of TAS2R mRNA and protein were determined by reverse-transcription polymerase chain reaction and Western blotting, respectively. The location of TAS2R was determined by immunofluorescence imaging. TAS2R agonists were used in a sensitive myograph to study the function of TAS2R in arteries. Key findingsThe mRNA of rat TAS2Rs, including rTAS2R39, rTAS2R40, rTAS2R108, rTAS2R114, rTAS2R130, rTAS2R137, and rTAS2R140, was expressed in rat mesenteric and cerebral arteries, but rTAS2R114 was not expressed in the cerebral arteries. The mRNA of human TAS2Rs, including hTAS2R3, hTAS2R4, hTAS2R7, hTAS2R10, hTAS2R14, hTAS2R39 and hTAS2R40, was expressed in human omental arteries. The TAS2R7 protein was expressed in rat mesenteric and cerebral arteries, as well as in human omental arteries. Immunofluorescence imaging confirmed that TAS2R7 was located in vascular smooth muscle cells and endothelial cells. The TAS2R agonists, chloroquine and quinine relaxed rat mesenteric arteries and cerebral arteries and human omental arteries in a concentration-dependent manner. SignificanceTAS2R is expressed in the arteries of systemic circulation, including rat mesenteric and cerebral arteries and human omental arteries. This study provides evidence that TAS2R do exist in the arteries and may be involved in the mediation of vessel functions.

Antimitogenic effect of bitter taste receptor agonists on airway smooth muscle cells

Airway remodeling is a hallmark feature of asthma and chronic obstructive pulmonary disease. Clinical studies and animal models have demonstrated increased airway smooth muscle (ASM) mass, and ASM thickness is correlated with severity of the disease. Current medications control inflammation and reverse airway obstruction effectively but have limited effect on remodeling. Recently we identified the expression of bitter taste receptors (TAS2R) on ASM cells, and activation with known TAS2R agonists resulted in ASM relaxation and bronchodilation. These studies suggest that TAS2R can be used as new therapeutic targets in the treatment of obstructive lung diseases. To further establish their effectiveness, in this study we aimed to determine the effects of TAS2R agonists on ASM growth and promitogenic signaling. Pretreatment of healthy and asthmatic human ASM cells with TAS2R agonists resulted in a dose-dependent inhibition of ASM proliferation. The antimitogenic effect of TAS2R ligands was not dependent on activation of protein kinase A, protein kinase C, or high/intermediate-conductance calcium-activated K(+) channels. Immunoblot analyses revealed that TAS2R agonists inhibit growth factor-activated protein kinase B phosphorylation without affecting the availability of phosphatidylinositol 3,4,5-trisphosphate, suggesting TAS2R agonists block signaling downstream of phosphatidylinositol 3-kinase. Furthermore, the antimitogenic effect of TAS2R agonists involved inhibition of induced transcription factors (activator protein-1, signal transducer and activator of transcription-3, E2 factor, nuclear factor of activated T cells) and inhibition of expression of multiple cell cycle regulatory genes, suggesting a direct inhibition of cell cycle progression. Collectively, these findings establish the antimitogenic effect of TAS2R agonists and identify a novel class of receptors and signaling pathways that can be targeted to reduce or prevent airway remodeling as well as bronchoconstriction in obstructive airway disease.

Targeting extra-oral bitter taste receptors modulates gastrointestinal motility with effects on satiation.

Bitter taste receptors (TAS2Rs) are present in extra-oral tissues, including gut endocrine cells. This study explored the presence and mechanism of action of TAS2R agonists on gut smooth muscle in vitro and investigated functional effects of intra-gastric administration of TAS2R agonists on gastric motility and satiation. TAS2Rs and taste signalling elements were expressed in smooth muscle tissue along the mouse gut and in human gastric smooth muscle cells (hGSMC). Bitter tastants induced concentration and region-dependent contractility changes in mouse intestinal muscle strips. Contractions induced by denatonium benzoate (DB) in gastric fundus were mediated via increases in intracellular Ca2+ release and extracellular Ca2+-influx, partially masked by a hyperpolarizing K+-efflux. Intra-gastric administration of DB in mice induced a TAS2R-dependent delay in gastric emptying. In hGSMC, bitter compounds evoked Ca2+-rises and increased ERK-phosphorylation. Healthy volunteers showed an impaired fundic relaxation in response to nutrient infusion and a decreased nutrient volume tolerance and increased satiation during an oral nutrient challenge test after intra-gastric DB administration. These findings suggest a potential role for intestinal TAS2Rs as therapeutic targets to alter gastrointestinal motility and hence to interfere with hunger signalling.

Pleiotropic Effects of Bitter Taste Receptors on [Ca2+]i Mobilization, Hyperpolarization, and Relaxation of Human Airway Smooth Muscle Cells.

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.

TAS2R bitter taste receptors regulate thyroid function.

Dysregulation of thyroid hormones triiodothyronine and thyroxine (T3/T4) can impact metabolism, body composition, and development. Thus, it is critical to identify novel mechanisms that impact T3/T4 production. We found that type 2 taste receptors (TAS2Rs), which are activated by bitter-tasting compounds such as those found in many foods and pharmaceuticals, negatively regulate thyroid-stimulating hormone (TSH)-dependent Ca(2+) increases and TSH-dependent iodide efflux in thyrocytes. Immunohistochemical Tas2r-dependent reporter expression and real-time PCR analyses reveal that human and mouse thyrocytes and the Nthy-Ori 3-1 human thyrocyte line express several TAS2Rs. Five different agonists for thyrocyte-expressed TAS2Rs reduced TSH-dependent Ca(2+) release in Nthy-Ori 3-1 cells, but not basal Ca(2+) levels, in a dose-dependent manner. Ca(2+) responses were unaffected by 6-n-propylthiouracil, consistent with the expression of an unresponsive variant of its cognate receptor, TAS2R38, in these cells. TAS2R agonists also inhibited basal and TSH-dependent iodide efflux. Furthermore, a common TAS2R42 polymorphism is associated with increased serum T4 levels in a human cohort. Our findings indicate that TAS2Rs couple the detection of bitter-tasting compounds to changes in thyrocyte function and T3/T4 production. Thus, TAS2Rs may mediate a protective response to overingestion of toxic materials and could serve as new druggable targets for therapeutic treatment of hypo- or hyperthyroidism.

Bitter taste receptor agonists elicit G-protein-dependent negative inotropy in the murine heart.

G-protein-coupled receptors (GPCRs) are key mediators in cardiovascular physiology, yet frontline therapies for heart disease target only a small fraction of the cardiac GPCR repertoire. Moreover, there is emerging evidence that GPCRs implicated in taste (Tas1r and Tas2rs) have specific functions beyond the oral cavity. Our recent description of these receptors in heart tissue foreshadows a potential novel role in cardiac cells. In this study, we identified novel agonist ligands for cardiac-Tas2rs to enable the functional investigation of these receptors in heart tissue. Five Tas2rs cloned from heart tissue were screened against a panel of 102 natural or synthetic bitter compounds in a heterologous expression system. We identified agonists for Tas2r108, Tas2r137, and Tas2r143 that were then tested in Langendorff-perfused mouse hearts (from 8-wk-old male C57BL/6 mice). All Tas2r agonists tested exhibited concentration-dependent effects, with agonists for Tas2r108 and Tas2r137, leading to a ∼40% decrease in left ventricular developed pressure and an increase in aortic pressure, respectively. These responses were abrogated in the presence of Gαi and Gβγ inhibitors (pertussis toxin and gallein). This study represents the first demonstration of profound Tas2r agonist-induced, G protein-dependent effects on mouse heart function.

Bitter taste receptor (TAS2R) agonists inhibit IgE-dependent mast cell activation

Bitter taste receptor (TAS2R) agonists inhibit IgE-dependent mast cell activation

Bitter tasting compounds dilate airways by inhibiting airway smooth muscle calcium oscillations and calcium sensitivity

While selective, bitter tasting, TAS2R agonists can relax agonist-contracted airway smooth muscle (ASM), their mechanism of action is unclear. However, ASM contraction is regulated by Ca²⁺ signalling and Ca²⁺ sensitivity. We have therefore investigated how the TAS2R10 agonists chloroquine, quinine and denotonium regulate contractile agonist-induced Ca²⁺ signalling and sensitivity. Airways in mouse lung slices were contracted with either methacholine (MCh) or 5HT and bronchodilation assessed using phase-contrast microscopy. Ca²⁺ signalling was measured with 2-photon fluorescence microscopy of ASM cells loaded with Oregon Green, a Ca²⁺-sensitive indicator (with or without caged-IP₃). Effects on Ca²⁺ sensitivity were assessed on lung slices treated with caffeine and ryanodine to permeabilize ASM cells to Ca²⁺ . The TAS2R10 agonists dilated airways constricted by either MCh or 5HT, accompanied by inhibition of agonist-induced Ca²⁺ oscillations. However, in non-contracted airways, TAS2R10 agonists, at concentrations that maximally dilated constricted airways, did not evoke Ca²⁺ signals in ASM cells. Ca²⁺ increases mediated by the photolysis of caged-IP₃ were also attenuated by chloroquine, quinine and denotonium. In Ca²⁺-permeabilized ASM cells, the TAS2R10 agonists dilated MCh- and 5HT-constricted airways. TAS2R10 agonists reversed bronchoconstriction by inhibiting agonist-induced Ca²⁺ oscillations while simultaneously reducing the Ca²⁺ sensitivity of ASM cells. Reduction of Ca²⁺ oscillations may be due to inhibition of Ca²⁺ release through IP₃ receptors. Further characterization of bronchodilatory TAS2R agonists may lead to the development of novel therapies for the treatment of bronchoconstrictive conditions.

The expression and relaxant effect of bitter taste receptors in human bronchi

BackgroundBitter-taste receptors (TAS2Rs) have recently been involved in the relaxation of mouse and guinea pig airways, and increased expression of TAS2Rs was shown in blood leucocytes from asthmatic children. We sought to identify and characterize the TAS2Rs expressed in isolated human bronchi and the subtypes involved in relaxation.MethodsHuman bronchi were isolated from resected lungs and TAS2R transcripts were assessed with RT-qPCR. Relaxation to TAS2R agonists was tested in organ bath in the presence or absence of pharmacological modulators of the signalling pathways involved in bronchial relaxation.ResultsWe detected the expression of TAS2R transcripts in human bronchi. The non-selective agonists chloroquine, quinine, caffeine, strychnine and diphenidol produced a bronchial relaxation as effective and potent as theophylline but much less potent than formoterol and isoproterenol. Denatonium, saccharin and colchicine did not produce relaxation. Receptor expression analysis together with the use of selective agonists suggest a predominant role for TAS2R5, 10 and 14 in bitter taste agonist-induced relaxation. The mechanism of relaxation was independent of the signalling pathways modulated by conventional bronchodilators and may be partly explained by the inhibition of phosphatidylinositol-3-kinases.ConclusionsThe TAS2Rs may constitute a new therapeutic target in chronic obstructive lung diseases such as asthma.

The bitter taste receptor (TAS2R) agonists denatonium and chloroquine display distinct patterns of relaxation of the guinea pig trachea

Activation of taste receptors (TAS2Rs) by bitter taste agonists has been reported to cause bronchodilation. The aim of this study was to extend the information on the effects of bitter taste agonists on responses induced by different contractile mediators in a standard airway physiology preparation. Isometric responses were assessed in guinea pig trachea (GPT). TAS2R agonists were administered either to segments precontracted with different agonists for contraction or given before challenge with the different contractile stimuli, including antigen in tissues from ovalbumin-sensitized animals. TAS2R mRNA expression on GPT epithelium and smooth muscle was measured with real-time PCR. Denatonium, chloroquine, thiamine, and noscapine induced concentration-dependent relaxations (R(max): 98.3 ± 1.6, 100.0 ± 0.0, 100.0 ± 0.0, and 52.3 ± 1.1% of maximum, respectively, in the presence of indomethacin) in segments precontracted with carbachol. The receptors for denatonium (TAS2R4, TAS2R10) and chloroquine (TAS2R3, TAS2R10) were expressed in GPT. Whereas denatonium selectively inhibited contractions induced by carbachol, chloroquine uniformly inhibited contractions evoked by prostaglandin E(2), the thromboxane receptor agonist U-46619, leukotriene D(4), histamine, and antigen. The effects of denatonium, but not those of chloroquine, were partly inhibited by blockers of the large Ca(2+)-activated K(+) channels and decreased by an increase of the level of precontraction. In conclusion, TAS2R agonists mediated strong relaxations and substantial inhibition of contractions in GPT. Chloroquine and denatonium had distinct patterns of activity, indicating different signaling mechanisms. The findings reinforce the hypothesis that TAS2Rs are potential targets for the development of a new class of more efficacious agonists for bronchodilation.

TAS2R activation promotes airway smooth muscle relaxation despite β2-adrenergic receptor tachyphylaxis

Recently, bitter taste receptors (TAS2Rs) were found in the lung and act to relax airway smooth muscle (ASM) via intracellular Ca(2+) concentration signaling generated from restricted phospholipase C activation. As potential therapy, TAS2R agonists could be add-on treatment when patients fail to achieve adequate bronchodilation with chronic β-agonists. The β(2)-adrenergic receptor (β(2)AR) of ASM undergoes extensive functional desensitization. It remains unknown whether this desensitization affects TAS2R function, by cross talk at the receptors or distal common components in the relaxation machinery. We studied intracellular signaling and cell mechanics using isolated human ASM, mouse tracheal responses, and human bronchial responses to characterize TAS2R relaxation in the context of β(2)AR desensitization. In isolated human ASM, magnetic twisting cytometry revealed >90% loss of isoproterenol-promoted decrease in cell stiffness after 18-h exposure to albuterol. Under these same conditions of β(2)AR desensitization, the TAS2R agonist chloroquine relaxation response was unaffected. TAS2R-mediated stimulation of intracellular Ca(2+) concentration in human ASM was unaltered by albuterol pretreatment, in contrast to cAMP signaling, which was desensitized by >90%. In mouse trachea, β(2)AR desensitization by β-agonist amounted to 92 ± 6.0% (P < 0.001), while, under these same conditions, TAS2R desensitization was not significant (11 ± 3.5%). In human lung slices, chronic β-agonist exposure culminated in 64 ± 5.7% (P < 0.001) desensitization of β(2)AR-mediated dilation of carbachol-constricted airways that was reversed by chloroquine. We conclude that there is no evidence for physiologically relevant cross-desensitization of TAS2R-mediated ASM relaxation from chronic β-agonist treatment. These findings portend a favorable therapeutic profile for TAS2R agonists for the treatment of bronchospasm in asthma or chronic obstructive lung disease.

Bronchodilator activity of bitter tastants in human tissue

Bronchodilator activity of bitter tastants in human tissue

Bronchodilator activity of bitter tastants in human tissue

776 volume 17 | number 7 | july 2011 nature medicine To the Editor: We read with interest the article by Deshpande et al.1 on bitter taste receptors (TAS2Rs) in the lungs and the expression of TAS2Rs on human airway smooth muscle (ASM). The authors describe experiments in which TAS2R agonists, such as chloroquine, evoked relaxation of mouse tracheal rings that was threefold greater in magnitude than that elicited by b-adrenergic receptor agonists1 (the current gold-standard bronchodilator therapy for asthma and chronic obstructive pulmonary disease2). We sought to investigate the uncharacteristically weak bronchodilator activity of isoproterenol in human tissue. After repeating key experiments from the paper by Deshpande et al.1 in our laboratories in the UK and in the laboratories of our collaborator in the US (B.J.C.), we obtained data that is consistent with a body of literature3 and clinical practice that suggests that isoproterenol is a potent and efficacious relaxant of human airway smooth muscle, eliciting a relaxation 4 log fold (10,000×) more potent than chloroquine, although both agents had similar efficacy (Fig. 1a,b). This difference in potency was apparent when we precontracted the human airway smooth muscle to 60–80% of the maximum attainable contraction with either 10 μM histamine (Fig. 1a) or 1 μM carbachol (Fig. 1b). We obtained comparable results in studies using airway smooth muscle preparations from guinea pigs, a species in which relaxation to b-agonists is elicited through the b2-adrenergic receptor (M.G.B., N.D., M.A.B. and B.J.C., unpublished observations). Several explanations could be proffered as to why there is a discrepancy between our results and those obtained by Deshpande et al.1 When performing in vitro tissue bath experiments to investigate the relaxant properties of agonists on ASM, standard practice is to precontract the tissue to establish a baseline level of bronchoconstrictor tone. The tone induced would normally be submaximal to avoid functional antagonism of the potential relaxant response4. However, the concentration of acetylcholine used by Deshpande et al.1 (0.1 mM) is supramaximal, which could functionally antagonize the relaxant response to isoproterenol, thereby making it appear smaller than expected. When we repeated these experiments under conditions of supramaximal tension (0.1 mM ACh), we also found that the relaxation to isoproterenol was compromised (60% of the maximal relaxation evoked by papaverine instead of 100%; Fig. 1c,d). We should emphasize that we do not question the author’s conclusions that airway smooth muscle from humans and mice express bitter taste receptors. This is potentially a physiologically important observation. We would respectfully suggest, however, that our data and the published literature cast doubt on the claim that TAS2R agonists are more effective bronchodilators than currently prescribed b2-adrenergic receptor agonists. Note: Supplementary information is available on the Nature Medicine website.

Bitter taste receptors on airway smooth muscle bronchodilate by localized calcium signaling and reverse obstruction

Bitter taste receptors (TAS2Rs) of the tongue likely 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, leading to ASM contraction and bronchospasm. TAS2R agonists such as saccharin, chloroquine and denatonium evoked increased ASM [Ca2+]i in a Gβγ, PLCβ and IP3-receptor dependent manner which would be expected (like acetylcholine) to evoke contraction. Paradoxically, bitter tastants caused relaxation of isolated ASM, and dilation of airways that was 3-fold greater than β-agonists. Relaxation by TAS2Rs is from a localized [Ca2+]i response at the cell membrane which opens BKCa channels leading to ASM membrane hyperpolarization. Inhaled bitter tastants decreased airway obstruction in an asthma mouse model. 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.

Expression of Bitter Taste Receptors in Human Bronchial airways Smooth Muscle Cells by using Immunofluorescence Staining

Asthma and chronic obstructive pulmonary diseases (COPDs) have been identified as one of the serious, public health concerns in the world, which results due to the host as well as the environmental factors. Based on the WHO, this disease will be the 3rdkiller disease worldwide by the year of 2020 following the cancer and heart disease. Concerning the asthma, there have been 389,000,000 individuals worldwide, afflicted by COPD and Asthma. Moreover, there has been a noticeable increase in the asthmatic incidences in the young adults and children by 4% to 5% yearly worldwide. Those two illnesses are fundamental global morbidity and mortality reasons, particularly in the patients that respond poorly to the current treatments. Which is why, there are unmet needs to come up with innovative therapies for the COPD as well as the asthma patients. Bitter taste receptors (TAS2R) are part of the family of the G-protein coupled receptors (GPCR). It was theorized previously that the TAS2R only expression on the tongue’s taste buds. The family of the TAS2R includes over 25 different subtypes of the receptors in the humans. Lately, a number of the researches showed that the TAS2R could be representing a new treatment target of the lung diseases. The TAS2R has been expressed in the human air-way smooth muscles (ASMs). It should be noted that TAS2Ractivation by the saccharin and chloroquine results in the induction of air-way relaxation. More significantly, bronchodilatory effects that result from the TAS2R agonists has been found greater compared to the β2 adrenergic receptor agonists, the basic bronchodilator medications in treating asthma. the bronchial airway smooth muscle (BASM) cells have been cultured from COPD (n=3), asthmatic (n=3), and healthy (n=3) individuals. The Immuno-fluorescence staining (with and with no permeabilize cells) have been conducted on 3 groups with the use of the poly-clonal anti-bodies against the (TAS2R10 as well as the TAS2R14) receptors. The immuno-fluorescence assays had shown that the TAS2R10 and TAR2R14 had shown a positive staining of the two receptors in the human ASM cells. It has been discovered as well that those two receptors have been expressed as well in nucleus.