In a healthy human, the airway mucus forms a thin, protective liquid layer covering the surface of the respiratory tract. It comprises a complex blend of mucin, multiple antibacterial proteins, metabolic substances, water, and electrolytes. This mucus plays a pivotal role in the lungs' innate immune system by maintaining airway hydration and capturing airborne particles and pathogens. However, heightened mucus secretion in the airway can compromise ciliary clearance, obstruct the respiratory tract, and increase the risk of pathogen colonization and recurrent infections. Consequently, a thorough exploration of the mechanisms driving excessive airway mucus secretion is crucial for establishing a theoretical foundation for the eventual development of targeted drugs designed to reduce mucus production. Across a range of lung diseases, excessive airway mucus secretion manifests with unique characteristics and regulatory mechanisms, all intricately linked to mucin. This article provides a comprehensive overview of the characteristics and regulatory mechanisms associated with excessive airway mucus secretion in several prevalent lung diseases.
Humans ; Mucus/metabolism* ; Mucins/physiology* ; Lung Diseases/metabolism* ; Respiratory Mucosa/metabolism* ; Pulmonary Disease, Chronic Obstructive/physiopathology* ; Asthma/physiopathology* ; Cystic Fibrosis/physiopathology* ; Mucociliary Clearance/physiology*

One of the main pathological features of airway inflammatory diseases is hypersecretion of airway mucus, which is manifested by goblet cell hyperplasia and mucociliary clearance dysfunction. In recent years, it has been found that the molecular structure of calcium activated chloride ion channels, transmenbrane protein 16A（TMEM16A）, is closely related to airway mucus hypersecretion.TMEM16A not only mediates ion transepithelial transport and hydration, but also participates in the regulation of mucin secretion. TMEM16A is highly expressed in airway epithelium of a variety of inflammatory diseases of upper and lower airway, such as asthma, cystic fibrosis, allergic rhinitis, chronic sinusitis and so on. Understanding the expression level and regulation mechanism of TMEM16A in different airway diseases and revealing its physiological function and pathological mechanism is critical for targeted disease treatment. This paper summarizes the research status of the discovery process, structural characteristics and regulatory mechanism of TMEM16A, and then summarizes the expression level of TMEM16A in asthma, cystic fibrosis, allergic rhinitis and chronic sinusitis ant related pathological mechanisms, clarifies the potential value of TMEM16A as a therapeutic target for the above four diseases, in order to guide treatment of airway inflammatory diseases.
Humans ; Asthma/metabolism* ; Anoctamin-1 ; Cystic Fibrosis/metabolism* ; Neoplasm Proteins/metabolism* ; Sinusitis/metabolism* ; Chloride Channels/metabolism* ; Rhinitis, Allergic/metabolism* ; Inflammation

ObjectiveAcute respiratory distress syndrome (ARDS) is an acute and lethal clinical syndrome that is characterized by the injury of alveolar epithelium, which impairs active fluid transport in the lung, and impedes the reabsorption of edema fluid from the alveolar space. This review aimed to discuss the role of pro-resolving mediators on the regulation of alveolar fluid clearance (AFC) in ARDS.

Data SourcesArticles published up to September 2017 were selected from the PubMed, with the keywords of "alveolar fluid clearance" or "lung edema" or "acute lung injury" or "acute respiratory distress syndrome", and "specialized pro-resolving mediators" or "lipoxin" or "resolvin" or "protectin" or "maresin" or "alveolar epithelial cells" or "aspirin-triggered lipid mediators" or "carbon monoxide and heme oxygenase" or "annexin A1".

Study SelectionWe included all relevant articles published up to September 2017, with no limitation of study design.

ResultsSpecialized pro-resolving mediators (SPMs), as the proinflammatory mediators, not only upregulated epithelial sodium channel, Na,K-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR), and aquaporins levels, but also improved Na,K-ATPase activity to promote AFC in ARDS. In addition to the direct effects on ion channels and pumps of the alveolar epithelium, the SPMs also inhibited the inflammatory cytokine expression and improved the alveolar epithelial cell repair to enhance the AFC in ARDS.

ConclusionsThe present review discusses a novel mechanism for pulmonary edema fluid reabsorption. SPMs might provide new opportunities to design "reabsorption-targeted" therapies with high degrees of precision in controlling ALI/ARDS.

Acute Lung Injury ; metabolism ; Animals ; Cystic Fibrosis Transmembrane Conductance Regulator ; metabolism ; Humans ; Respiratory Distress Syndrome, Adult ; metabolism

BACKGROUND: The incidence of lung cancer is gradually increased, and the cystic fibrosis transmembrane conductance regulator (CFTR) has recently demonstrated to have an implication in the deoncogenesis and malignant transformation of many types of cancers. The aim of this study is to investigate impacts of CFTR on the malignant features of lung adenocarcinoma A549 cells. METHODS: The capacity of cell proliferation, migration, invasion and clonogenicity of non-small cell lung cancer A549 cells were detected by CCK8 cell proliferation assay, cell scratch assay, Transwell cell invasion assay and clone formation assay, respectively. Meanwhile, the effect of CFTR gene on the expression of cancer stem cell related transcriptional factors was also detected by immunoblotting (Western blot) assay. RESULTS: An overexpression of CFTR gene in A549 cells significantly inhibited the malignant capacity of A549 cells, including potencies of cell proliferation, migration, invasion and colony formation; while knockdown of CFTR gene expression by RNA interference in A549 cells resulted in an opposite effect seen in above cells overexpressing CFTR gene. Mechanistically, immunoblotting assay further revealed that the ectopic expression of CFTR gene led an inhibitory expression of stem cell-related transcriptional factors SOX2 and OCT3/4, and cancer stem cell surface marker CD133 in A549 cells, while a knockdown of CFTR expression yielded a moderately increased expression of these gene. However, an alteration of CFTR gene expression had neither effect on the expression of putative lung cancer stem cell marker aldehyde dehydrogenase1 (ALDH1), nor the frequency of ALDH1A-positive cells in A549 cells, as ascertained by the immunoblotting assay and cytometry analysis, respectively. CONCLUSIONS The CFTR exhibited an inhibitory role in the malignancy of lung adenocarcinoma A549 cells, suggesting that it may be a novel potential target for lung cancer treatment. However, its functions in other lung adenocarcinoma cell lines and its underlying molecular mechanisms require further investigation.
A549 Cells ; Adenocarcinoma ; pathology ; Adenocarcinoma of Lung ; Cell Movement ; genetics ; Cell Proliferation ; genetics ; Cystic Fibrosis Transmembrane Conductance Regulator ; metabolism ; Humans ; Lung Neoplasms ; pathology ; Mutation ; Neoplasm Invasiveness ; Neoplastic Stem Cells ; pathology ; Proto-Oncogene Proteins p21(ras) ; genetics

OBJECTIVETo study the impact of the chloride channel dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) on the cytoskeleton of Sertoli cells in the mouse.

METHODSTM4 Sertoli cells were cultured and treated with CFTR(inh)-172 at the concentrations of 1, 5, 10 and 20 μmol/L for 48 hours. Then the cytotoxicity of CFT(inh)-172 was assessed by CCK-8 assay, the expressions of F-actin and Ac-tub in the TM4 Sertoli cells detected by immunofluorescence assay, and those of N-cadherin, vimentin and vinculin determined by qPCR.

RESULTSCFTR(inh)-172 produced cytotoxicity to the TM4 Sertoli cells at the concentration of 20 μmol/L. The expressions of F-actin and Ac-tub were decreased gradually in the TM4 Sertoli cells with the prolonging of treatment time and increasing concentration of CFTR(inh)-172 (P < 0.05). The results of qPCR showed that different concentrations of CFTR(inh)-172 worked no significant influence on the mRNA expressions of N-cadherin, vimentin and vinculin in the Sertoli cells.

CONCLUSIONThe CFTR chloride channel plays an important role in maintaining the normal cytoskeleton of Sertoli cells. The reduced function and expression of the CFTR chloride channel may affect the function of Sertoli cells and consequently spermatogenesis of the testis.

Actins ; metabolism ; Animals ; Benzoates ; pharmacology ; Chloride Channels ; physiology ; Cystic Fibrosis Transmembrane Conductance Regulator ; antagonists & inhibitors ; Cytoskeleton ; drug effects ; Male ; Mice ; Sertoli Cells ; drug effects ; metabolism ; Spermatogenesis ; Thiazolidines ; pharmacology ; Time Factors

Cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent chloride channel, plays key roles in fluid secretion in serous epithelial cells. Previously, we identified two polymethoxylated flavonoids, 3',4',5,5',6,7-hexamethoxyflavone (HMF) and 5-hydroxy-6,7,3',4'-tetramethoxyflavone (HTF) which could potentiate CFTR chloride channel activities. The present study was aimed to investigate the potentiation effects of HMF and HTF on CFTR Cl(-) channel activities by using a cell-based fluorescence assay and the short circuit Ussing chamber assay. The results of cell-based fluorescence assay showed that both HMF and HTF could dose-dependently potentiate CFTR Cl(-) channel activities in rapid and reversible ways, and the activations could be reversed by the CFTR blocker CFTRinh-172. Notably, HMF showed the highest affinity (EC50 = 2 μmol/L) to CFTR protein among the flavonoid CFTR activators identified so far. The activation of CFTR by HMF or HTF was forskolin (FSK) dependent. Both compounds showed additive effect with FSK and 3-Isobutyl-1-methylx (IBMX) in the activation of CFTR, while had no additive effect with genistein (GEN). In ex vivo studies, HMF and HTF could stimulate transepithelial Cl(-) secretion in rat colonic mucosa and enhance fluid secretion in mouse trachea submucosal glands. These results suggest that HMF and HTF may potentiate CFTR Cl(-) channel activities through both elevation of cAMP level and binding to CFTR protein pathways. The results provide new clues in elucidating structure and activity relationship of flavonoid CFTR activators. HMF might be developed as a new drug in the therapy of CFTR-related diseases such as bronchiectasis and habitual constipation.
Animals ; Colforsin ; Colon ; metabolism ; Cystic Fibrosis Transmembrane Conductance Regulator ; drug effects ; Flavones ; physiology ; Flavonoids ; pharmacology ; Genistein ; Intestinal Mucosa ; metabolism ; Mice ; Rats

OBJECTIVETo determine the expression pattern of Slc26a3 gene in reproductive tract of male rodents to clarify whether the expression pattern is related to the subfertility observed in congenital chloride diarrhea (CLD) disease.

METHODSThe expression of Slc26a3 in mouse and rat epididymis has been studied with immunohistochemistry and Western blotting. Its developmental expression pattern in rat testis was detected by Western blotting, while both of immunofluorescence and Western blotting were used to localize the expression of Slc26a3 in mouse sperms. The potential change of Slc26a3 expression in CFTR (cystic fibrosis transmembrane conductance regulator) knockout mice and CFTR mutant mice was also detected with Western blotting.

RESULTSThe expression level of Slc26a3 gradually decreased along epididymis from its caput to corpus, then to its cauda part. This gradually decreasing expression pattern was also found in rat testis during development. Slc26a3 was localized mainly on the trunk of mouse sperm tail. In the testis and epididymis of CFTR knockout mice and CFTR mutant mice, no significant change of Slc26a3 expression was found.

CONCLUSIONSlc26a3 is expressed in male reproductive tract, and its expression pattern is related to the function. Thus, the subfertility observed in CLD disease may be related to the important role of SLC26A3 in acid-base regulation of epididymis.

Animals ; Antiporters ; genetics ; metabolism ; Blotting, Western ; Cystic Fibrosis Transmembrane Conductance Regulator ; genetics ; metabolism ; Diarrhea ; congenital ; genetics ; metabolism ; Epididymis ; growth & development ; metabolism ; Immunohistochemistry ; Male ; Metabolism, Inborn Errors ; genetics ; metabolism ; Mice, Inbred CFTR ; Mice, Inbred ICR ; Mice, Knockout ; Rats, Sprague-Dawley ; Spermatozoa ; metabolism ; Testis ; growth & development ; metabolism

OBJECTIVE: To observe the effect of tympanic injection of dexamethasone in the guinea pig endolymphatic hydrops and the change CFTR expression, to explore the effect of glucocorticoid treatment endolymphatic and its possible mechanism. METHOD: Thirty guinea pigs were divided into three groups: hormone group, water group, control group. The animals(hormone group, water group) in study were injected DDAVP 4 μg/kg in the first 7 d, and will increase to 6 μg/kg in the second 3 d. The control group was given normal saline, continuous 10 d. After twelfth days, the hormone group transtympanic injection of dexamethasone (5 mg/ml, 0.5 ml), and water group, control group transtympanic given normal saline (0.5 ml), continuous injection 5 d. Using immuno- histochemistry and Western blot to detect the cystic fibrosis transmembrane conductance regulator cochlear factor (CFTR) expression. RESULT: The water group ABR thresholds was significantly higher than that before the experiment (P < 0.01), and the water group was significantly higher than the rest of the groups (P < 0.01); Hormone group compared with the control group increased threshold value (P < 0.05). The control group had no endolym- phatic hydrops, the water group showed varying degrees of endolymphatic hydrops, cochlear duct and vestibular plus cochlear duct area ratio compared with the control group, hormone group was significantly higher (P < 0.01). hormone group area ratio was higher than the control group (P < 0.05). CFTR was primarily expressed in the stria vascularis, Corti's, spiral ligament, basilar membrane, cochlear ganglion,etc . The expression of CFTR in the water group was increased than that in the control group, and the hormone group (P < 0.01); the expression of hormone group increased compared with the control group (P < 0.05). CONCLUSION Tympanic injection of dexa- methasone can alleviate the desmopressin acetatein guinea pigs caused by membranous labyrinth, and the improve- ment of the hearing; Tympanic injection of dexamethasone can make the endolymphatic hydrops cochlea of guinea pigs decreased CFTR expression, indicating that the expression and possible mechanisms of CFTR intratympanic steroids reduce endolymphatic hydrops changes.
Animals ; Cochlea ; Cystic Fibrosis Transmembrane Conductance Regulator ; biosynthesis ; Dexamethasone ; pharmacology ; Ear, Inner ; Endolymphatic Hydrops ; drug therapy ; metabolism ; Glucocorticoids ; pharmacology ; Guinea Pigs ; Stria Vascularis

OBJECTIVETo investigate the effects of Weile Powder (WLP) on bicarbonate transporters in rats with gastric ulcers, and to probe its functional mechanisms.

METHODSThe 48 SD rats were randomly divided into the normal control group, the model group, the low dose WLP group (at the daily dose of 0.075 g/mL), the middle dose WLP group (at the daily dose of 0.150 g/mL), the high dose WLP group (at the daily dose of 0.030 g/mL), and the ranitidine group (at the daily dose of 0.030 g/mL), 8 in each group. The gastric ulcer rat model was prepared by the glacial acetic acid cauterization method. Rats in each medication group were administered from the 2nd day of modeling. Rats were sacrificed after 14-day successive medication. The protein was extracted from the ulcer tissue. The protein expressions of solute carrier26A3 (SLC26A3)and solute carrier26A6 (SLC26A6) were detected using Western blot. The gastric ulcer and its peripheral tissue were sectioned. The changes of cystic fibrosis transmembrane conductance regulator (CFTR) were measured by immunofluorescence.

RESULTSCompared with the model control group, the expression levels of SLC26A3 increased in the high dose WLP group and the ranitidine group with statistical difference (P < 0.05). The expression levels of SLC26A6 increased in the high and middle dose WLP groups and the ranitidine group with statistical difference (P < 0.05). The expression level of CFTR also obviously increased in the high and middle dose WLP groups (P < 0.01).

CONCLUSIONWLP could elevate the expression levels of SLC26A6, SLC26A3, and CFTR, increase the secretion of bicarbonate, thus protecting the gastric mucosa.

Animals ; Antiporters ; metabolism ; Bicarbonates ; metabolism ; Cystic Fibrosis Transmembrane Conductance Regulator ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Female ; Gastric Mucosa ; drug effects ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Stomach Ulcer ; metabolism

Aim of the present study is to investigate activation effect of nobiletin on cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel activity. CFTR-mediated iodide influx assay and patch-clamp tests were done on FRT cells stably co-transfected with human CFTR and EYFP/H148Q. Nobiletin potently activated CFTR chloride channel activity in a dose- and time-dependent manner. The CFTR blocker CFTR(inh)-172 could completely reverse the effect. Preliminary mechanism study indicated that nobiletin activated CFTR chloride channel through a direct binding way. In addition, ex vivo tests done on mice trachea showed that nobiletin time-dependently stimulated submucosal gland fluid secretion. Nobiletin may be a therapeutic lead compound in treating CFTR-related diseases including disseminated bronchiectasis.
Animals ; Benzoates ; pharmacology ; Cystic Fibrosis Transmembrane Conductance Regulator ; antagonists & inhibitors ; drug effects ; metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells ; metabolism ; Exocrine Glands ; secretion ; Flavones ; administration & dosage ; pharmacology ; Humans ; Mice ; Patch-Clamp Techniques ; Rats ; Rats, Inbred F344 ; Thiazolidines ; pharmacology ; Thyroid Gland ; cytology ; Time Factors ; Trachea ; secretion