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*

Individuals with congenital absence of the vas deferens (CAVD) may transmit cystic fibrosis (CF)-causing variants of the cystic fibrosis transmembrane conductance regulator ( CFTR ) gene to their offspring through assisted reproductive technology (ART). We aimed to delineate the spectrum and estimate the prevalence of CF-causing variants in Chinese individuals with CAVD through a cohort analysis and meta-analysis. CFTR was sequenced in 145 Chinese individuals with CAVD. CFTR variants were classified as CF-causing or non-CF-causing variants regarding clinical significance. A comprehensive genotype analysis was performed in Chinese individuals with CAVD, incorporating previous studies and our study cohort. The prevalence of CF-causing variants was estimated through meta-analysis. In our cohort, 56 different CFTR variants were identified in 108 (74.5%) patients. Twenty variants were categorized as CF-causing and were detected in 28 (19.3%) patients. A comprehensive genotype analysis of 867 patients identified 174 different CFTR variants. Sixty-four were classified as CF-causing variants, 56.3% of which had not been previously reported in Chinese patients with CF. Meta-analysis showed that 14.8% (95% confidence interval [CI]: 11.0%-18.9%) CAVD cases harbored one CF-causing variant, and 68.6% (95% CI: 65.1%-72.0%) CAVD cases carried at least one CFTR variant. Our study underscores the urgent need for extensive CFTR screening, including sequencing of whole exons and flanking regions and detection of large rearrangements and deep intronic CF-causing variants, in Chinese individuals with CAVD before undergoing ART. The established CF-causing variants spectrum may aid in the development of genetic counseling strategies and preimplantation diagnosis to prevent the birth of a child with CF.
Adult ; Humans ; Male ; China ; Cohort Studies ; Cystic Fibrosis/genetics* ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Genotype ; Male Urogenital Diseases/genetics* ; Mutation ; Vas Deferens/abnormalities* ; East Asian People/genetics*

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

Cytoskeletal network dysregulation is a pivotal determinant in various immunodeficiencies and autoinflammatory conditions. This report reviews the significance of actin remodeling in disease pathogenesis, focusing on the Arp2/3 complex and its regulatory subunit actin related protein 2/3 complex subunit 1B (ARPC1B). A spectrum of cellular dysfunctions associated with ARPC1B deficiency, impacting diverse immune cell types, is elucidated. The study presents a patient featuring recurrent and persistent eosinophilia attributed to homozygous ARPC1B mutation alongside concomitant compound heterozygous cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. We used ARPC1B antibody to stain the patient's peripheral blood lymphocytes and those of the control. The defect in the ARPC1B gene in the present patient caused absent/low expression by immunofluorescence microscopy. The intricate interplay between cytoskeletal defects and immunological manifestations underscores the complexity of disease phenotypes, warranting further exploration for targeted therapeutic strategies.
Humans ; Actin-Related Protein 2-3 Complex/genetics* ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Eosinophilia/genetics* ; Homozygote ; Mutation ; Recurrence

Cystic Fibrosis (CF) is a rare condition among Asians and has not been reported in the Philippines as of this time. The inclusion of this disease in the Philippines’ Expanded Newborn Screening Program (ENBS) has provided this Filipino family the opportunity of early detection and appropriate management of this condition that could ensure the survival of the proband and his other surviving siblings. Here we present a case of a 24-month-old male who had a positive Expanded Newborn Screening (ENBS) test for cystic fibrosis and eventually underwent further tests to confirm a homozygous deletion of exons 1 - 2 of the CFTR gene. He subsequently had recurrent pneumonia but is being managed by a team consisting of a pulmonologist, gastroenterologist, and a metabolic dietitian. The proband had an older sibling whose Newborn Screening (NBS) test was normal and who eventually expired from recurrent bouts of pneumonia. This sibling was never managed as a case of cystic fibrosis. Implications on the diagnosis and management of CF in the local setting is also discussed. The importance of an appropriate CF panel customized to the local population should be reiterated and carrier testing should be encouraged to help with proper family counseling for future pregnancies for the family involved.
Cystic Fibrosis ; Neonatal Screening ; Philippines

Objective: To evaluate the value of nasal nitric oxide (nNO) measurement as a diagnostic tool for Chinese patients with primary ciliary dyskinesia (PCD). Methods: This study is a retrospective study. The patients were recruited from those who were admitted to the respiratory Department of Respiratory Medicine, Children's Hospital of Fudan University from March 2018 to September 2022. Children with PCD were included as the PCD group, and children with situs inversus or ambiguus, cystic fibrosis (CF), bronchiectasis, chronic suppurative lung disease and asthma were included as the PCD symptom-similar group. Children who visited the Department of Child health Care and urology in the same hospital from December 2022 to January 2023 were selected as nNO normal control group. nNO was measured during plateau exhalation against resistance in three groups. Mann-Whitney U test was used to analyze the nNO data. The receiver operating characteristic of nNO value for the diagnosis of PCD was plotted and, the area under the curve and Youden index was calculated to find the best cut-off value. Results: nNO was measured in 40 patients with PCD group, 75 PCD symptom-similar group (including 23 cases of situs inversus or ambiguus, 8 cases of CF, 26 cases of bronchiectasis or chronic suppurative lung disease, 18 cases of asthma), and 55 nNO normal controls group. The age of the three groups was respectively 9.7 (6.7,13.4), 9.3 (7.0,13.0) and 9.9 (7.3,13.0) years old. nNO values were significantly lower in children with PCD than in PCD symptom-similar group and nNO normal controls (12 (9,19) vs. 182 (121,222), 209 (165,261) nl/min, U=143.00, 2.00, both P<0.001). In the PCD symptom-similar group, situs inversus or ambiguus, CF, bronchiectasis or chronic suppurative lung disease and asthma were significantly higher than children with PCD (185 (123,218), 97 (52, 132), 154 (31, 202), 266 (202,414) vs. 12 (9,19) nl/min,U=1.00, 9.00, 133.00, 0, all P<0.001). A cut-off value of 84 nl/min could provide the best sensitivity (0.98) and specificity (0.92) with an area under the curve of 0.97 (95%CI 0.95-1.00, P<0.001). Conclusions: nNO value can draw a distinction between patients with PCD and others. A cut-off value of 84 nl/min is recommended for children with PCD.
Humans ; Child ; Adolescent ; Nitric Oxide ; Retrospective Studies ; Cystic Fibrosis ; Bronchiectasis/diagnosis* ; Asthma/diagnosis* ; Hospitals, Pediatric ; Ciliary Motility Disorders/diagnosis*

Congenital bilateral absence of the vas deferens (CBAVD) is observed in 1%-2% of males presenting with infertility and is clearly associated with cystic fibrosis transmembrane conductance regulator (CFTR) mutations. CFTR is one of the most well-known genes related to male fertility. The frequency of CFTR mutations or impaired CFTR expression is increased in men with nonobstructive azoospermia (NOA). CFTR mutations are highly polymorphic and have established ethnic specificity. Compared with F508Del in Caucasians, the p.G970D mutation is reported to be the most frequent CFTR mutation in Chinese patients with cystic fibrosis. However, whether p.G970D participates in male infertility remains unknown. Herein, a loss-of-function CFTR p.G970D missense mutation was identified in a patient with CBAVD and NOA. Subsequent retrospective analysis of 122 Chinese patients with CBAVD showed that the mutation is a common pathogenic mutation (4.1%, 5/122), excluding polymorphic sites. Furthermore, we generated model cell lines derived from mouse testes harboring the homozygous Cftr p.G965D mutation equivalent to the CFTR variant in patients. The Cftr p.G965D mutation may be lethal in spermatogonial stem cells and spermatogonia and affect the proliferation of spermatocytes and Sertoli cells. In spermatocyte GC-2(spd)ts (GC2) Cftr p.G965D cells, RNA splicing variants were detected and CFTR expression decreased, which may contribute to the phenotypes associated with impaired spermatogenesis. Thus, this study indicated that the CFTR p.G970D missense mutation might be a pathogenic mutation for CBAVD in Chinese males and associated with impaired spermatogenesis by affecting the proliferation of germ cells.
Humans ; Animals ; Mice ; Male ; Mutation, Missense ; Retrospective Studies ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Infertility, Male/genetics* ; Mutation ; Vas Deferens/abnormalities* ; Spermatogenesis/genetics*

Male ; Humans ; Mutation, Missense ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Infertility, Male/genetics* ; Genetic Testing ; Mutation ; Vas Deferens

Objective: To establish a detection method based on Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) that can sensitively detect the second messenger cyclic AMP (cAMP) in the cytoplasm. Methods: The eukaryotic expression vectors of CFTR and YFP-H148Q / I152L were constructed respectively. FRT cells co-expressing CFTR and YFP-H148Q / I152L were obtained by liposome transfection. The expression of CFTR and YFP-H148Q / I152L in FRT cells was observed by an inverted fluorescence microscopy, and flow cytometry was used to detect the purity of cells; The cell model was identified by the fluorescence quenching kinetics test. The validation of the cell model which could screen CFTR modulators was verified by the fluorescence quenching kinetics experiments. The radioimmunoassay was used to detect the cAMP concentration in cytoplasm after adding CFTR activator. Results: The results of the inverted fluorescence microscope showed that CFTR was expressed in the cell membrane and YFP-H148Q / I152L was expressed in the cytoplasm of FRT cells. The FRT cell model stably co-expressing ANO1 and YFP-H148Q / I152L was successfully constructed. The model could screen CFTR modulators, and the slope of fluorescence change and the concentration of CFTR modulators were in a dose-dependent manner. The slope of the fluorescence could reflect the cAMP concentration in the cytoplasm. The cell model could sensitively detect the intracellular cAMP concentration. Conclusion: The cell model could efficiently and sensitively detect the second messenger cAMP concentration in the cytoplasm, and it provided a simple and efficient method for the study of other targets associated cAMP signal.
Cyclic AMP ; Cystic Fibrosis Transmembrane Conductance Regulator ; Cytoplasm ; Second Messenger Systems

Cystic fibrosis (CF) is a rare autosomal recessive disease with only one pathogenic gene cystic fibrosis transmembrane conductance regulator (CFTR). To identify the potential pathogenic mutations in a Chinese patient with CF, we conducted Sanger sequencing on the genomic DNA of the patient and his parents and detected all 27 coding exons of CFTR and their flanking intronic regions. The patient is a compound heterozygote of c.2909G > A, p.Gly970Asp in exon 18 and c.1210-3C > G in cis with a poly-T of 5T (T5) sequence, 3 bp upstream in intron 9. The splicing effect of c.1210-3C > G was verified via minigene assay in vitro, indicating that wild-type plasmid containing c.1210-3C together with T7 sequence produced a normal transcript and partial exon 10-skipping-transcript, whereas mutant plasmid containing c.1210-3G in cis with T5 sequence caused almost all mRNA to skip exon 10. Overall, c.1210-3C > G, the newly identified pathogenic mutation in our patient, in combination with T5 sequence in cis, affects the CFTR gene splicing and produces nearly no normal transcript in vitro. Moreover, this patient carries a p.Gly970Asp mutation, thus confirming the high-frequency of this mutation in Chinese patients with CF.
China ; Cystic Fibrosis/genetics* ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Humans ; Mutation ; Poly T ; RNA, Messenger/genetics*