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Pawin Pongkorpsakol,1,* Chantapol Yimnual,2,* Wilasinee Satianrapapong,3 Nichakorn Worakajit,4 Suchada Kaewin,2 Praphatsorn Saetang,5 Vatcharin Rukachaisirikul,5 Chatchai Muanprasat2 1Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand; 2Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand; 3Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 4Program in Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 5Division of Physical Science and Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Songkhla, Thailand*These authors contributed equally to this workCorrespondence: Chatchai Muanprasat, Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand, Tel +66-85-2949658, Email chatchai.mua@mahidol.ac.thIntroduction: Inhibition of Ca2+-activated transmembrane protein 16A (TMEM16A) Cl− channels has been proposed to alleviate mucus secretion in asthma. In this study, we identified a novel class of TMEM16A inhibitors from natural sources in airway epithelial Calu-3 cells and determine anti-asthmatic efficacy of the most potent candidate in a mouse model of asthma.Methods: For electrophysiological analyses, IL-4-primed Calu-3 cell monolayers were mounted in Ussing chamber and treated with various fungus-derived depsidones prior to the addition of UTP, ionomycin, thapsigargin, or Eact to stimulate TMEM16A Cl− current. Ca2+-induced mucus secretion in Calu-3 cell monolayers was assessed by determining MUC5AC protein remaining in the cells using immunofluorescence staining. OVA-induced female BALB/c mice was used as an animal model of asthma. After the course of induction, cellular and mucus components in bronchoalveolar lavage were analyzed. Lungs were fixed and undergone with H&E and PAS staining for the evaluation of airway inflammation and mucus production, respectively.Results: The screening of fungus-derived depsidones revealed that nornidulin completely abolished the UTP-activated TMEM16A current in Calu-3 cell monolayers with the IC50 and a maximal effect being at ~0.8 μM and 10 μM, respectively. Neither cell viability nor barrier function was affected by nornidulin. Mechanistically, nornidulin (10 μM) suppressed Cl− currents induced by ionomycin (a Ca2+-specific ionophore), thapsigargin (an inhibitor of the endoplasmic reticulum Ca2+ ATPase), and Eact (a putative TMEM16A activator) without interfering with intracellular Ca2+ ([Ca2+]i) levels. These results suggest that nornidulin exerts its effect without changing [Ca2+]i, possibly through direct effect on TMEM16A. Interestingly, nornidulin (at 10 μM) reduced Ca2+-dependent mucus release in the Calu-3 cell monolayers. In addition, nornidulin (20 mg/kg) inhibited bronchoalveolar mucus secretion without impeding airway inflammation in ovalbumin-induced asthmatic mice.Discussion and Conclusion: Our study revealed that nornidulin is a novel TMEM16A inhibitor that suppresses mucus secretion without compromising immunologic activity. Further development of nornidulin may provide a new remedy for asthma or other diseases associated with allergic mucus hypersecretion without causing opportunistic infections.Keywords: TMEM16a, nornidulin, asthma, mucus secretion, airway epithelium

Background: Article 5.3 of the WHO Framework Convention on Tobacco Control (FCTC) was developed to protect public health policies from tobacco industry interference. The guiding principles of Article 5.3 emphasise a fundamental conflict between the tobacco industry's interests and public health interests (principle 1) and recommend that the government be accountable and transparent (principle 2), demand accountability and transparency from the industry (principle 3), and refrain from providing incentives to the industry (principle 4). This study quantitatively explored attitudes towards Article 5.3's guiding principles and recommendations among Thai tobacco control stakeholders and whether they were associated with awareness of tobacco industry tactics., Methods: We conducted an online survey of 703 individuals involved in tobacco control in Thailand . We employed multivariable ordinal logistic regression analysis to explore factors associated with attitudes towards Article 5.3's guiding principles and recommendations., Results: 441 participants responded to the survey (response rate 62.7%). Among the Article 5.3 guiding principles, principle 1 received the lowest agreement (83%), whereas the other three principles had an average of 93% agreement. In multivariable ordinal logistic regression, we found awareness of tobacco industry tactics was associated with Article 5.3's guiding principles: principle 1 (adjusted OR (AOR) 1.11; 95% CI 1.07 to 1.15; p<0.001), principle 2 (AOR 1.07; 95% CI 1.02 to 1.12; p=0.002), principle 3 (AOR 1.11; 95% CI 1.06 to 1.15; p<0.001) and principle 4 (AOR 1.14; 95% CI 1.09 to 1.19; p<0.001). In addition to awareness of tobacco industry tactics, age, years of experience in tobacco control, role in tobacco control and smoking by family members and friends were associated with perspectives towards Article 5.3's guidelines., Conclusions: This study provides quantitative evidence of the association between attitudes towards WHO FCTC Article 5.3 and awareness of tobacco industry tactics in Thailand. Denormalisation of the tobacco industry is thus a vital component of successfully implementing and enforcing Article 5.3., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Airway remodeling is associated with severity and treatment insensitivity in asthma. This study aimed to investigate the effects of G protein-coupled receptor 120 (GPR120) stimulation on alleviating allergic inflammation and remodeling of airway epithelium., Research Design and Methods: Ovalbumin (OVA)-challenged BALB/c mice and type-2-cytokine (IL-4 and IL-13)-exposed 16HBE human bronchial epithelial cells were treated with GSK137647A, a selective GPR120 agonist. Markers of allergic inflammation and airway remodeling were determined., Results: GSK137647A attenuated inflammation and mucus secretion in airway epithelium of OVA-challenged mice. Stimulation of GPR120 in 16HBE suppressed expression of asthma-associated cytokines and cytokine-induced expression of pathogenic mucin-MUC5AC. These effects were abolished by co-treatment with AH7614, a GPR120 antagonist. Moreover, GPR120 stimulation in 16HBE cells reduced expression of fibrotic markers including fibronectin protein and ACTA2 mRNA and inhibited epithelial barrier leakage induced by type-2 inflammation via rescuing expression of zonula occludens-1 protein. Furthermore, GPR120 stimulation prevented the cytokine-induced airway epithelial remodeling via suppression of STAT6 and Akt phosphorylation., Conclusions: Our findings suggest that GPR120 activation alleviates allergic inflammation and remodeling of airway epithelium partly through inhibition of STAT6 and Akt. GPR120 may represent a novel therapeutic target for diseases associated with remodeling of airway epithelium, including asthma., Competing Interests: Declaration of Competing Interest There are none., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

TMEM16A is a Ca 2+ -activated Cl - channel involved in mucus secretion in inflamed airways and proposed as a drug target for diseases associated with mucus hypersecretion including asthma. This study aimed to identify novel inhibitors of TMEM16A-mediated Cl - secretion in airway epithelial cells from a collection of compounds isolated from fungi indigenous in Thailand and examine its potential utility in mitigating airway mucus secretion using Calu-3 cells as a study model. Screening of > 400 fungal metabolites revealed purpactin A isolated from a soil-derived fungus Penicillium aculeatum PSU-RSPG105 as an inhibitor of TMEM16A-mediated Cl - transport with an IC 50 value of ~2 µM. A consistent inhibitory effect of purpactin A on TMEM16A were observed regardless of TMEM16A activators or in the presence of an inhibitor of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII), a negative regulator of TMEM16A. In addition, purpactin A did not affect cell viability, epithelial barrier integrity and activities of membrane transport proteins essential for maintaining airway hydration including CFTR Cl - channels and apical BK K + channels. Intriguingly, purpactin A prevented a Ca 2+ -induced mucin release in cytokine-treated airway cells. Taken together, purpactin A represents the first class of TMEM16A inhibitor derived from fungus, which may be beneficial for the treatment of diseases associated with mucus hypersecretion., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Intestinal Cl - secretion is involved in the pathogenesis of secretory diarrheas including cholera. We recently demonstrated that flufenamic acid (FFA) suppressed Vibrio cholerae El Tor variant-induced intestinal fluid secretion via mechanisms involving AMPK activation and NF-κB-suppression. The present study aimed to investigate the effect of FFA on transepithelial Cl - secretion in human intestinal epithelial (T84) cells. FFA inhibited cAMP-dependent Cl - secretion in T84 cell monolayers with IC 50 of ∼8 μM. Other fenamate drugs including tolfenamic acid, meclofenamic acid and mefenamic acid exhibited the same effect albeit with lower potency. FFA also inhibited activities of CFTR, a cAMP-activated apical Cl - channel, and KCNQ1/KCNE3, a cAMP-activated basolateral K + channel. Mechanisms of CFTR inhibition by FFA did not involve activation of its negative regulators. Interestingly, FFA inhibited Ca 2+ -dependent Cl - secretion with IC 50 of ∼10 μM. FFA inhibited activities of Ca 2+ -activated Cl - channels and K Ca 3.1, a Ca 2+ -activated basolateral K + channels, but had no effect on activities of Na + -K + -Cl - cotransporters and Na + -K + ATPases. These results indicate that FFA inhibits both cAMP and Ca 2+ -dependent Cl - secretion by suppressing activities of both apical Cl - channels and basolateral K + channels. FFA and other fenamate drugs may be useful in the treatment of secretory diarrheas., (Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)