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Objective To investigate the inhibitory effect of limonin on airway inflammation and mucus hypersecre-tion. Methods The experiment was divided into three groups(n=10),namely blank control group,PM2.5 group (the rat models of chronic airway inflammation were established by aerosolized PM2.5 suspension) and PM2.5+limonin group(intervening with the extract from tangerine peel). mRNA,protein of inflammatory cytokines,mucin (MUC) and TAS2Rs were measured by ELISA,RT-PCR and Western blot respectively. Results The mRNA and protein expression of IL-1β, CINC-1 and MUC5AC and MUC5B in PM2.5 group were significantly higher than those in control group(P<0.05),and the expression of MUC5AC protein in broncho alveolar lavage fluid(BALF) was increased. Compared with PM2.5 stimulated group,mRNA and protein of TAS2R14 in PM2.5+limonin inter-vented group were significantly higher (P<0.05). Moreover, the expression of IL-1β, CINC-1 and MUC5AC, MUC5B was lower than PM2.5 group (P<0.05).While the expression of MUC5B was mainly increased in BALF.Conclusions The production of mucin can be inhibited by aerosolized limonin, meanwhile the secretion of mucin also can be promoted.This effect is achieved by activating the expression of TAS2Rs in the lungs, which enhances the anti-inflammatory effect of airway inflammation.
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Recent findings indicate that Type 2 taste receptors (T2Rs) are expressed outside the gustatory system, including in the gastrointestinal tracts and the exocrine glands, such as the submandibular (SM), parotid (P), lacrimal (L) glands and pancreas (PC). Specifically, T2Rs are found in some of the gastrointestinal endocrine cells, and these cells secreted peptide hormones in response to stimulation by bitter-tasting compounds. The results show that T2Rs may have significant physiological roles besides bitter taste reception. The functions of the T2Rs in the exocrine glands remain poorly understood. An expression levels analysis of T2Rs will help to determine those functions in the exocrine glands. The expression levels of the T2Rs in the exocrine glands were discovered via the qPCR. C57BL/6J mice of 42~60-day-old were used. Messenger RNAs were extracted from S, P, L and PC. Cloned DNAs were synthesized by reverse transcription. Quantitative PCRs were performed using the SYBR Green method. The expression levels of the T2Rs were calculated as relative expression levels to that of the GAPDH. The statistical significance among the observed exocrine glands was tested using the variance analysis (ANOVA test). Tas2r108, out of murine 35 T2Rs, was the most highly expressed in every observed exocrine gland. This finding was similar to previous results from tongue papillae, but the expression levels were lower than those of the tongue papillae. Tas2r137 of SM, P, L and PC were expressed a little lower than that of tongue papillae. The T2Rs in the exocrine glands may play slightly different roles from those in the tongue. We suggest that physiological studies such as a patch clamp and functional Ca²⁺ imaging of acinar cells are necessary for understanding the Tas2r108 functions.
Subject(s)
Animals , Mice , Acinar Cells , Clone Cells , DNA , Enteroendocrine Cells , Exocrine Glands , Gastrointestinal Tract , Methods , Pancreas , Peptide Hormones , Polymerase Chain Reaction , Reverse Transcription , RNA, Messenger , TongueABSTRACT
Objective:To investigate the anti-inflammatory effects of bitter taste receptor (TAS2Rs) in the treatment of chronic airway inflammation by bitter Chinese medicine.Methods: The experiment was divided into three groups (n=8),namely blank control group,PM2.5 group (the rat models of chronic airway inflammation were established by aerosolized PM2.5 suspension) and PM2.5+limonin group (intervening with the extract from Tangerine peel).The expression of mRNA and protein of inflammatory cytokines and TAS2Rs in bronchial/pulmonary tissue were detected by ELISA,RT-PCR and Western blot respectively.Results: The mRNA and protein expression levels of TNF-α and IL-13 in PM2.5 stimulated group were significantly higher than those in control group,while the TAS2R14 were not significantly changed.The mRNA and protein expression levels of TNF-α and IL-13 in the limonin intervention group was lower than that in the PM2.5 group,and the TAS2R14 were significantly increased.Conclusion: The production and release of inflammatory cytokines in the chronic inflammatory airway can be curbed by inhaling the components of bitter Chinese herbal medicine.And then,the TAS2Rs in the lungs can be activated by the bitter components to increase its expression.Therefore,it is considered that bitter Chinese herbal medicine to play the airway anti-inflammatory effect is achieved through the activation of the airway TAS2Rs.
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Objective To evaluate the effect of denatonium benzoaten on α-smooth muscle actin (α-SMA),subepithelial collagen and airway inflammation in asthmu mice.Methods Forty-five BALB/c mice were divided into 3 groups,normal control group (A group),asthma model group (B group),asthma model+ denatonium benzoaten group(C group);α-SMA detected by using immunohistochemistry,lung sections were stained with Masson to detect subepithelial collagen,HE stain method was used to observe the airway inflammation the images were analyzed with semi-quantitative computer.Results The deposition of α-SMA、subepithelial collagen and inflammation degree in C group was significantly reduced compared with B group,the difference were statistically significant(P＜0.05).Conclusion Denatonium benzoaten can improve airway remodeling in asthmatic mice.
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number of goblet cells, mucus secretion and mucin MUC5AC content in lung tissues. Results S100A9 in BALF of group B was (11.89±0.77) ng/mL, S100A9 integrated optical density (IOD) value in airway epithelial cells was 13.96±1.62, PAS stain area /epithelial cell area was (12.53±1.21)%, relative value of MUC5AC / NADPH was 173.91±4.29, all of the above were higher than those of group A [(6.19±0.61) ng/mL, 4.97±0.30, (1.94±0.18)%, 1];S100A9 levels, IOD of S100A9 in airway epithelial cells, PAS stain area / epithelial cell area (%), relative value of MUC5AC / NADPH in group C [(10.69±0.79) ng / ml, 11.80±0.72, (10.61±0.61)%, 94.65±1.59], group D[(9.49±0.99) ng/mL, 10.39±0.59, (8.63±0.62)%, 82.08±1.12], group E [(7.54± 0.42) ng/mL, 5.63±0.84, (4.59±0.87)%, 26.30±1.94] were lower than group B, which showed a dose-dependent reduction and the difference was statistically significant (P<0.05 or P<0.01). Conclusion DB downregulates the expression level of Ca2+-binding protein S100A9 and the mucus secretion amount of the airway goblet cells in rats.
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Objective: To construct high-throughput screening cell model targeting TAS2R14 receptor and lay the foundation for the search of effective, novel natural anti-asthma drugs with low toxicity. Methods: The pLVX-AcGFP1-N1-TAS2R14 lentivirus vector carrying green fluorescent protein (GFP) was constructed. The lentiviral vector was transfected into HEK HEK293T cells, collected high titer lentiviral concentration liquid and infected HEK293T cells, established cell model highly specific expressed TAS2R14 receptor gene. The TAS2R14 cell model was used to screen 120 kinds of Chinese herb extracts and chemical monomers. Results: The calculated Z' values of the cell model were 0.69 and 0.66, and Citri Reticulatae Pericarpium extract and its efficacy material limonin, Ginkgo Semen extract and its efficacy material rutin and quinine agitated TAS2R14 cell model. Conclusion: The constructed TAS2R14 cell model is stable and sensitive for screening anti-asthma drugs, and three kinds of Chinese materia medica monomers have the potential agonist the activity on TAS2R14 receptor.
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The nasal cavity encounters various irritants during inhalation such as dust and pathogens. To detect and remove these irritants, it has been postulated that the nasal mucosa epithelium has a specialized sensing system. The oral cavity, on the other hand, is known to have bitter taste receptors (T2Rs) that can detect harmful substances to prevent ingestion. Recently, solitary chemosensory cells expressing T2R subtypes have been found in the respiratory epithelium of rodents. In addition, T2Rs have been identified in the human airway epithelia. However, it is not clear which T2Rs are expressed in the human nasal mucosa epithelium and whether they mediate the removal of foreign materials through increased cilia movement. In our current study, we show that human T2R receptors indeed function also in the nasal mucosa epithelium. Our RT-PCR data indicate that the T2R subtypes (T2R3, T2R4, T2R5, T2R10, T2R13, T2R14, T2R39, T2R43, T2R44, T2R 45, T2R46, T2R47, T2R48, T2R49, and T2R50) are expressed in human nasal mucosa. Furthermore, we have found that T2R receptor activators such as bitter chemicals augments the ciliary beating frequency. Our results thus demonstrate that T2Rs are likely to function in the cleanup of inhaled dust and pathogens by increasing ciliary movement. This would suggest that T2Rs are feasible molecular targets for the development of novel treatment strategies for nasal infection and inflammation.