Cardiopulmonary crisis caused by bronchial blocker malposition in a patient with aberrant tracheal anatomy: a case report.

BACKGROUND: Double-lumen tubes (DLTs) and bronchial blockers (BBs) can be used to establish one-lung ventilation (OLV) for thoracic surgery. BBs are a good alternative when DLTs are not suitable or patients have difficult airways. However, BBs are more prone to malposition, leading to adverse events. CASE PRESENTATION: We present a 68-year-old male patient who was scheduled for thoracoscopic left lower lobectomy. The patient was not expected to have airway malformation preoperatively. When the DLT could not be inserted into the bronchus after general anesthesia induction, we used a BB to perform OLV. During surgery, malposition of the BB resulted in the development of an "incomplete balloon valve", leading to a cardiopulmonary crisis. CONCLUSIONS: Previewing chest computed tomography scans to assess the airway anatomy before thoracic surgery is essential. Three-dimensional reconstruction of the airway can provide a more intuitive assessment of airway anatomy. During OLV with BBs, we should pay attention to balloon malposition to prevent cardiopulmonary crises.

p27 specifically decreases in squamous carcinoma, and mediates NNK-induced transformation of human bronchial epithelial cells.

Lung cancer remains the leading cause of cancer-related deaths, with cigarette smoking being the most critical factor, linked to nearly 90% of lung cancer cases. NNK, a highly carcinogenic nitrosamine found in tobacco, is implicated in the lung cancer-causing effects of cigarette smoke. Although NNK is known to mutate or activate certain oncogenes, its potential interaction with p27 in modulating these carcinogenic effects is currently unexplored. Recent studies have identified specific downregulation of p27 in human squamous cell carcinoma, in contrast to adenocarcinoma. Additionally, exposure to NNK significantly suppresses p27 expression in human bronchial epithelial cells. Subsequent studies indicates that the downregulation of p27 is pivotal in NNK-induced cell transformation. Mechanistic investigations have shown that reduced p27 expression leads to increased level of ITCH, which facilitates the degradation of Jun B protein. This degradation in turn, augments miR-494 expression and its direct regulation of JAK1 mRNA stability and protein expression, ultimately activating STAT3 and driving cell transformation. In summary, our findings reveal that: (1) the downregulation of p27 increases Jun B expression by upregulating Jun B E3 ligase ITCH, which then boosts miR-494 transcription; (2) Elevated miR-494 directly binds to 3'-UTR of JAK1 mRNA, enhancing its stability and protein expression; and (3) The JAK1/STAT3 pathway is a downstream effector of p27, mediating the oncogenic effect of NNK in lung cancer. These findings provide significant insight into understanding the participation of mechanisms underlying p27 inhibition of NNK induced lung squamous cell carcinogenic effect.

An alternative bronchoscopic transparenchymal nodule access by "invisible tunnel" technique under electromagnetic navigation without the transbronchial access tool.

BACKGROUND: The diagnosis of peripheral pulmonary lesions (PPL) is still challenging. We describe a novel method for sampling PPL without bronchial signs by creating invisible tunnel under electromagnetic navigation without the transbronchial access tool (TABT). METHODS: During electromagnetic navigation, we adjust the angle of the edge extended working channel catheter based on the real-time position of the lesion in relation to the locating guide rather than preset route. A biopsy brush or biopsy forceps is used to punch a hole in the bronchial wall. A locating guide is then re-inserted to real-time navigate through the lung parenchyma to the lesion. Safety and feasibility of this method was analyzed. RESULTS: A total of 32 patients who underwent electromagnetic navigation bronchoscopy were retrieved. The mean size of the lesion is 23.1 mm. The mean operative time of all patients was 12.4 min. Ten of the patients did not have a direct airway to the lesion, thus creating an invisible tunnel. For them, the length of the tunnel from the bronchial wall POE to the lesion was 11-30 mm, with a mean length of 16.9 mm and a mean operation time of 14.1 min. Adequate samples were obtained from 32 patients (100%), and the diagnostic yield was 87.5% (28/32). Diagnostic yield of with create the invisible tunnel TBAT was 90% (9/10), and one patient undergone pneumothorax after operation. CONCLUSIONS: This method is feasible and safe as a novel approach sampling pulmonary lesions without bronchial signs, and it further improves current tunnel technique.

[Role of reactive oxygen species/silent information regulator 1 in hyperoxia-induced bronchial epithelial cell injury]. / 活性氧簇/æ²‰é»˜ä¿¡æ¯è°ƒèŠ‚å› å­1在高氧致支气管上皮细胞损伤中的作用.

OBJECTIVES: To investigate the effect of reactive oxygen species (ROS)/silent information regulator 1 (SIRT1) on hyperoxia-induced mitochondrial injury in BEAS-2B cells. METHODS: The experiment was divided into three parts. In the first part, cells were divided into H0, H6, H12, H24, and H48 groups. In the second part, cells were divided into control group, H48 group, H48 hyperoxia+SIRT1 inhibitor group (H48+EX 527 group), and H48 hyperoxia+SIRT1 agonist group (H48+SRT1720 group). In the third part, cells were divided into control group, 48-hour hyperoxia+N-acetylcysteine group (H48+NAC group), and H48 group. The ROS kit was used to measure the level of ROS. Western blot and immunofluorescent staining were used to measure the expression levels of SIRT1 and mitochondria-related proteins. Transmission electron microscopy was used to observe the morphology of mitochondria. RESULTS: Compared with the H0 group, the H6, H12, H24, and H48 groups had a significantly increased fluorescence intensity of ROS (P<0.05), the H48 group had significant reductions in the expression levels of SIRT1 protein and mitochondria-related proteins (P<0.05), and the H24 and H48 groups had a significant reduction in the fluorescence intensity of mitochondria-related proteins (P<0.05). Compared with the H48 group, the H48+SRT1720 group had significant increases in the expression levels of mitochondria-related proteins and the mitochondrial aspect ratio (P<0.05), and the H48+EX 527 group had a significant reduction in the mitochondrial area (P<0.05). Compared with the H48 group, the H48+NAC group had a significantly decreased fluorescence intensity of ROS (P<0.05) and significantly increased levels of SIRT1 protein, mitochondria-related proteins, mitochondrial area, and mitochondrial aspect ratio (P<0.05). CONCLUSIONS: The ROS/SIRT1 axis is involved in hyperoxia-induced mitochondrial injury in BEAS-2B cells.

Distinctive field effects of smoking and lung cancer case-control status on bronchial basal cell growth and signaling.

RATIONAL: Basal cells (BCs) are bronchial progenitor/stem cells that can regenerate injured airway that, in smokers, may undergo malignant transformation. As a model for early stages of lung carcinogenesis, we set out to characterize cytologically normal BC outgrowths from never-smokers and ever-smokers without cancers (controls), as well as from the normal epithelial "field" of ever-smokers with anatomically remote cancers, including lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) (cases). METHODS: Primary BCs were cultured and expanded from endobronchial brushings taken remote from the site of clinical or visible lesions/tumors. Donor subgroups were tested for growth, morphology, and underlying molecular features by qRT-PCR, RNAseq, flow cytometry, immunofluorescence, and immunoblot. RESULTS: (a) the BC population includes epithelial cell adhesion molecule (EpCAM) positive and negative cell subsets; (b) smoking reduced overall BC proliferation corresponding with a 2.6-fold reduction in the EpCAMpos/ITGA6 pos/CD24pos stem cell fraction; (c) LUSC donor cells demonstrated up to 2.8-fold increase in dysmorphic BCs; and (d) cells procured from LUAD patients displayed increased proliferation and S-phase cell cycle fractions. These differences corresponded with: (i) disparate NOTCH1/NOTCH2 transcript expression and altered expression of potential downstream (ii) E-cadherin (CDH1), tumor protein-63 (TP63), secretoglobin family 1a member 1 (SCGB1A1), and Hairy/enhancer-of-split related with YRPW motif 1 (HEY1); and (iii) reduced EPCAM and increased NK2 homeobox-1 (NKX2-1) mRNA expression in LUAD donor BCs. CONCLUSIONS: These and other findings demonstrate impacts of donor age, smoking, and lung cancer case-control status on BC phenotypic and molecular traits and may suggest Notch signaling pathway deregulation during early human lung cancer pathogenesis.

Cotton Ball Aspiration Leading to Pulmonary Complications in a Child.

BACKGROUND Foreign body aspiration (FBA) is a common and serious problem in childhood that requires early recognition and treatment. Common complications include asphyxia, hemorrhage, infection, and pneumothorax. In severe cases of foreign body obstruction, death can result from asphyxia. We report an interesting case in which a forgotten cotton ball was inhaled into the lungs. CASE REPORT A 5-year-old boy presented to the local hospital with coughing for 6 days and fever for 4 days, without any information of foreign body aspiration upon admission. Laboratory findings indicated an elevated white blood cell; therefore, cefprozil was given as anti-infective treatment. However, the child's condition did not improve. A computed tomography scan showed left pulmonary atelectasis. Considering that the child's condition was serious, he was referred to our hospital for diagnosis and treatment. After referral, auscultation revealed decreased breath sounds over the left lung. After multidisciplinary discussion, combined with the results of auxiliary examination, the possibility of a foreign body was considered. He underwent rigid bronchoscopy, which confirmed a yellow-white foreign body in the left main bronchus that was later verified as a cotton ball. The operation was very successful. Eventually, his condition improved and he was discharged, without additional complications. CONCLUSIONS For children with unclear history of foreign body aspiration, bronchoscopy is recommended if there is recurrent pulmonary infection, low auscultation breath sounds, or abnormal imaging. The choice of surgical method depends on the location and type of foreign body and the experience of the surgeon, which is also very important.

Vitamin D ameliorates particulate matter induced mitochondrial damages and calcium dyshomeostasis in BEAS-2B human bronchial epithelial cells.

BACKGROUND: Mitochondria is prone to oxidative damage by endogenous and exogenous sources of free radicals, including particulate matter (PM). Given the role of mitochondria in inflammatory disorders, such as asthma and chronic obstructive pulmonary disease, we hypothesized that supplementation of vitamin D may play a protective role in PM-induced mitochondrial oxidative damages of human bronchial epithelial BEAS-2B cells. METHODS: BEAS-2B cells were pretreated with 1,25(OH)2D3, an active form of vitamin D, for 1 h prior to 24-hour exposure to PM (SRM-1648a). Oxidative stress was measured by flow cytometry. Mitochondrial functions including mitochondrial membrane potential, ATP levels, and mitochondrial DNA copy number were analyzed. Additionally, mitochondrial ultrastructure was examined using transmission electron microscopy. Intracellular and mitochondrial calcium concentration changes were assessed using flow cytometry based on the expression of Fluo-4 AM and Rhod-2 AM, respectively. Pro-inflammatory cytokines, including IL-6 and MCP-1, were quantified using ELISA. The expression levels of antioxidants, including SOD1, SOD2, CAT, GSH, and NADPH, were determined. RESULTS: Our findings first showed that 24-hour exposure to PM led to the overproduction of reactive oxygen species (ROS) derived from mitochondria. PM-induced mitochondrial oxidation resulted in intracellular calcium accumulation, particularly within mitochondria, and alterations in mitochondrial morphology and functions. These changes included loss of mitochondrial membrane integrity, disarrayed cristae, mitochondrial membrane depolarization, reduced ATP production, and increased mitochondrial DNA copy number. Consequently, PM-induced mitochondrial damage triggered the release of certain inflammatory cytokines, such as IL-6 and MCP-1. Similar to the actions of mitochondrial ROS inhibitor MitoTEMPO, 1,25(OH)2D3 conferred protective effects on mtDNA alterations, mitochondrial damages, calcium dyshomeostasis, thereby decreasing the release of certain inflammatory cytokines. We found that greater cellular level of 1,25(OH)2D3 upregulated the expression of enzymatic (SOD1, SOD2, and CAT) and non-enzymatic (GSH and NADPH) antioxidants to modulate cellular redox homeostasis. CONCLUSION: Our study provides new evidence that 1,25(OH)2D3 acts as an antioxidant, enhancing BEAS-2B antioxidant responses to regulate mitochondrial ROS homeostasis and mitochondrial function, thereby enhancing epithelial defense against air pollution exposure.

[Left Upper Lobectomy for Lung Cancer Arising in a Displaced Anomalous Bronchus:Report of a Case].

A 69-year-old man was diagnosed with an abnormal shadow on a chest X-ray during a routine check-up. Computed tomography (CT) showed a 36 mm solid nodule at left S1+2, and 3 dimentional (3D)-CT showed the left B1+2 branching from the left main bronchus. Bronchoscopy showed branching of B1+2, B3~5, and inferior lobar bronchus from the left main bronchus, and a biopsy from the peripheral area of B1+2 confirmed the diagnosis of lung adenocarcinoma. Subsequently, video-assisted thoracoscopic surgery was performed for the lung adenocarcinoma (cT2aN0M0, ⅠB). The dorsal pleura was incised and B1+2, which branches from the left main bronchus dorsal to the pulmonary artery, was identified. After dissecting B1+2, the fissure between the upper division and lower lobes was separated, followed by left upper lobectomy with ND2a-1. The preoperative understanding of the anatomical abnormalities obtained using 3D-CT allowed the surgery to be performed safely.

A case report of high-grade intraepithelial neoplasia of the bronchial mucosa.

BACKGROUND: Lung cancer is the most common cause of cancer death worldwide and poses an immediate health threat. Despite decades of basic and clinical research, the 5-year survival rate for lung cancer patients is less than 10%.The most important drawbacks in efficient treatment of lung cancer are delayed diagnosis and absence of effective screening. Detection and study of precancerous lesions of the bronchial mucosa might be one of the turning points in understanding of neoplastic transformation. Therefore, it would be the most effective prevention and early treatment modality. We report a case of high-grade intraepithelial neoplasia of the bronchial mucosa in which a neoplastic growth in the lumen of intrinsic segment in the upper lobe of the left lung was detected on electronic bronchoscopy, and biopsy confirmed squamous papillary hyperplasia with high-grade intraepithelial neoplasia. CASE PRESENTATION: A 74-year-old male was admitted to the hospital due to a mass lesion in his left lung. After admission, computed tomography scan of the chest showed an intraluminal mass in the intrinsic segment of the upper lobe of the left lung and an enlarged left hilum. CONCLUSIONS: High-grade intraepithelial neoplasia of the bronchial mucosa is rare in the respiratory system. We report a case that can provide useful information for early diagnosis and treatment of the disease.

Esophageal Bronchus-the Hidden Link. A Case Report.

An esophageal bronchus is a subtype of congenital bronchopulmonary foregut malformations in which a lobar bronchus arises directly from the esophagus, creating a communication between the esophagus and lung tissue. Early diagnosis is crucial to prevent worsening pulmonary sequelae but is challenging due to the rarity of the anomaly and nonspecific respiratory symptoms. We present a child whose esophageal bronchus was identified incidentally during preanesthetic assessment for craniosynostosis repair and discuss the role an anesthesiologist can play in identifying and managing this diagnosis.

Extracellular Vesicles Induce Nuclear Factor-κB Activation and Interleukin-8 Synthesis through miRNA-191-5p Contributing to Inflammatory Processes: Potential Implications in the Pathogenesis of Chronic Obstructive Pulmonary Disease.

Extracellular vesicles (EVs) play a pivotal role in a variety of physiologically relevant processes, including lung inflammation. Recent attention has been directed toward EV-derived microRNAs (miRNAs), such as miR-191-5p, particularly in the context of inflammation. Here, we investigated the impact of miR-191-5p-enriched EVs on the activation of NF-κB and the expression of molecules associated with inflammation such as interleukin-8 (IL-8). To this aim, cells of bronchial epithelial origin, 16HBE, were transfected with miR-191-5p mimic and inhibitor and subsequently subjected to stimulations to generate EVs. Then, bronchial epithelial cells were exposed to the obtained EVs to evaluate the activation of NF-κB and IL-8 levels. Additionally, we conducted a preliminary investigation to analyze the expression profiles of miR-191-5p in EVs isolated from the plasma of patients diagnosed with chronic obstructive pulmonary disease (COPD). Our initial findings revealed two significant observations. First, the exposure of bronchial epithelial cells to miR-191-5p-enriched EVs activated the NF-kB signaling and increased the synthesis of IL-8. Second, we discovered the presence of miR-191-5p in peripheral blood-derived EVs from COPD patients and noted a correlation between miR-191-5p levels and inflammatory and functional parameters. Collectively, these data corroborate and further expand the proinflammatory role of EVs, with a specific emphasis on miR-191-5p as a key cargo involved in this process. Consequently, we propose a model in which miR-191-5p, carried by EVs, plays a role in airway inflammation and may contribute to the pathogenesis of COPD.

18F-DCFPyL PSMA PET/CT Tracheobronchial Uptake in Patients with Prostate Cancer: Incidence and Etiology.

We evaluated the incidence and potential etiology of tracheobronchial uptake in patients being evaluated by 18F-DCFPyL PET/CT for prostate cancer (PCa). Methods: The study included a consecutive 100 PCa patients referred for 18F-DCFPyL PET/CT. The PET/CT scans were retrospectively reviewed. The presence or absence of physiologic tracheobronchial uptake on PET/CT was recorded. To further evaluate tracheal prostate-specific membrane antigen (PSMA) expression, immunohistochemistry was performed on tracheal samples taken from 2 men who had surgical resection of lung cancer. Results: Tracheal uptake was present in 31 of 100 patients (31%). When tracheal uptake was present, the SUVmax was significantly higher in the left main bronchus (mean, 2.7) than in the right (mean, 2.3) (P < 0.001). Histopathologic testing of tracheobronchial samples showed PSMA expression in bronchial submucosal glands. Conclusion: In PCa patients undergoing 18F-DCFPyL PET/CT, tracheobronchial uptake occurred in 31% of patients. This is attributed to normal physiologic PSMA expression in bronchial submucosal glands.

Right uniportal video-assisted thoracoscopic surgery lung-sparing sleeve resection of the bronchus intermedius

Complete surgical resection has been the main treatment modality for pulmonary neoplasms without locoregional or distant spread of the disease. Sleeve resections were developed to minimize unnecessary loss of pulmonary parenchyma mainly in the case of centrally located tumours. Experience with sleeve resections and recent technological advancements made minimally invasive resection possible for selected patients. We present a case report of the totally thoracoscopic uniportal sleeve resection of the bronchus intermedius without any resection of pulmonary parenchyma. The operation was performed successfully, and the patient did not experience any postoperative complications. In this case report, we describe our surgical approach and short-term results.

Analysis of Methylome of Different Forms of Basal Cell Hyperplasia and Squamous Cell Metaplasia of Bronchial Epithelium.

Squamous cell lung cancer (SCLC) occurs as a result of dysregenerative changes in the bronchial epithelium: basal cell hyperplasia (BCH), squamous cell metaplasia (SM), and dysplasia. We previously suggested that combinations of precancerous changes detected in the small bronchi of patients with SCLC may reflect various "scenarios" of the precancerous process: isolated BCH→stopping at the stage of hyperplasia, BCH+SM→progression of hyperplasia into metaplasia, SM+dysplasia→progression of metaplasia into dysplasia. In this study, DNA methylome of various forms of precancerous changes in the bronchial epithelium of SCLC patients was analyzed using the genome-wide bisulfite sequencing. In BCH combined with SM, in contrast to isolated BCH, differentially methylated regions were identified in genes of the pathogenetically significant MET signaling pathway (RNMT, HPN). Differentially methylated regions affecting genes involved in inflammation regulation (IL-23, IL-23R, IL12B, IL12RB1, and FIS1) were detected in SM combined with dysplasia in comparison with SM combined with BCH. The revealed changes in DNA methylation may underlie various "scenarios" of the precancerous process in the bronchial epithelium.

Modulation of Bronchial Epithelial Barrier Integrity by Low Molecular Weight Components from Birch Pollen.

Pollen, in addition to allergens, comprise low molecular weight components (LMC) smaller than 3 kDa. Emerging evidence indicates the relevance of LMC in allergic immune responses. However, the interaction of birch pollen (BP)-derived LMC and epithelial cells has not been extensively studied. We investigated epithelial barrier modifications induced by exposure to BP LMC, using the human bronchial epithelial cell line 16HBE14o-. Epithelial cell monolayers were apically exposed to the major BP allergen Bet v 1, aqueous BP extract or BP-derived LMC. Barrier integrity after the treatments was monitored by measuring transepithelial electrical resistance at regular intervals and by using the xCELLigence Real-Time Cell Analysis system. The polarized release of cytokines 24 h following treatment was measured using a multiplex immunoassay. Epithelial barrier integrity was significantly enhanced upon exposure to BP LMC. Moreover, BP LMC induced the repair of papain-mediated epithelial barrier damage. The apical release of CCL5 and TNF-α was significantly reduced after exposure to BP LMC, while the basolateral release of IL-6 significantly increased. In conclusion, the results of our study demonstrate that BP-derived LMC modify the physical and immunological properties of bronchial epithelial cells and thus regulate airway epithelial barrier responses.

The feasibility and accuracy of the method for selecting the optimal size of double-lumen tube in thoracic surgery: a prospective, randomized controlled trial.

Double-lumen tubes (DLTs) are commonly used for one-lung ventilation (OLV) in thoracic surgery and the selection of an optimal size of DLTs is still a humongous task. The purpose of this study was to assess the feasibility and accuracy of the method for selecting an optimal size of DLTs in thoracic surgery. Sixty adult patients requiring a left side double-lumen tube (LDLT) for elective thoracoscopic surgery were included in this study. All patients were randomly allocated to the following two groups: Cuffs Collapsed group (CC group, n = 30) and Cuffs Inflated group (CI group, n = 30). In the Cuffs Collapsed group, the outer diameter of LDLT (the outer diameter of the tracheal and bronchial cuffs when they were collapsed as the outer diameter of the LDLT) matched with the inner diameter of the trachea and bronchus measured by the anesthesiologist on the chest CT slice; In the Cuffs Inflated group, the outer diameter of LDLT (the outer diameter of the tracheal and bronchial cuffs when they were inflated as the outer diameter of the LDLT) matched with the inner diameter of the trachea and bronchus measured by the anesthesiologist on the chest CT slice. The primary outcomes were the incidences of airway complications postoperative such as hoarseness and sore throat. The time of intubation and alignment, the incidences of LDLT displacement and adjustment, the peak airway pressure, the plateau airway pressure and the end-tidal carbon dioxide were also recorded. The incidences of airway complications postoperative such as sore throat and hoarseness were lower in the CI group than the CC group (P < 0.05), the intubation times was shorter in the CI group than the CC group (P < 0.05), while the peak airway pressure, the plateau airway pressure and the end-tidal carbon dioxide during two-lung ventilation and one-lung ventilation were no significant difference between two groups (P > 0.05). The method which matched the inner diameter of the trachea and bronchus measured on chest CT slice with the outer diameter of the tracheal and bronchial cuffs when they were inflated to select an appropriate size of LDLT can reduce the incidence of airway complications.Trials registration: Clinical Trials: gov. no. NCT05739318. Registered at https://classic.clinicaltrials.gov 22/02/2023.

Dynamics for High-Sensitivity Detection of Free Radicals in Primary Bronchial Epithelial Cells upon Stimulation with Cigarette Smoke Extract.

Chronic obstructive pulmonary disease (COPD), the third leading cause of death worldwide, is caused by chronic exposure to toxic particles and gases, such as cigarette smoke. Free radicals, which are produced during a stress response to toxic particles, play a crucial role in disease progression. Measuring these radicals is difficult since the complex mixture of chemicals within cigarette smoke interferes with radical detection. We used a new quantum sensing technique called relaxometry to measure free radicals with nanoscale resolution on cells from COPD patients and healthy controls exposed to cigarette smoke extract (CSE) or control medium. Epithelial cells from COPD patients display a higher free radical load than those from healthy donors and are more vulnerable to CSE. We show that epithelial cells of COPD patients are more susceptible to the damaging effects of cigarette smoke, leading to increased release of free radicals.

Reduced sialylation of airway mucin impairs mucus transport by altering the biophysical properties of mucin.

Mucus stasis is a pathologic hallmark of muco-obstructive diseases, including cystic fibrosis (CF). Mucins, the principal component of mucus, are extensively modified with hydroxyl (O)-linked glycans, which are largely terminated by sialic acid. Sialic acid is a negatively charged monosaccharide and contributes to the biochemical/biophysical properties of mucins. Reports suggest that mucin sialylation may be altered in CF; however, the consequences of reduced sialylation on mucus clearance have not been fully determined. Here, we investigated the consequences of reduced sialylation on the charge state and conformation of the most prominent airway mucin, MUC5B, and defined the functional consequences of reduced sialylation on mucociliary transport (MCT). Reduced sialylation contributed to a lower charged MUC5B form and decreased polymer expansion. The inhibition of total mucin sialylation de novo impaired MCT in primary human bronchial epithelial cells and rat airways, and specific α-2,3 sialylation blockade was sufficient to recapitulate these findings. Finally, we show that ST3 beta-galactoside alpha-2,3-sialyltransferase (ST3Gal1) expression is downregulated in CF and partially restored by correcting CFTR via Elexacaftor/Tezacaftor/Ivacaftor treatment. Overall, this study demonstrates the importance of mucin sialylation in mucus clearance and identifies decreased sialylation by ST3Gal1 as a possible therapeutic target in CF and potentially other muco-obstructive diseases.

ETS1 and RBPJ transcriptionally regulate METTL14 to suppress TGF-ß1-induced epithelial-mesenchymal transition in human bronchial epithelial cells.

Asthma is a chronic respiratory disease characterized by airway inflammation and remodeling. Epithelial-mesenchymal transition (EMT) of bronchial epithelial cells is considered to be a crucial player in asthma. Methyltransferase-like 14 (METTL14), an RNA methyltransferase, is implicated in multiple pathological processes, including EMT, cell proliferation and migration. However, the role of METTL14 in asthma remains uncertain. This research aimed to explore the biological functions of METTL14 in asthma and its underlying upstream mechanisms. METTL14 expression was down-regulated in asthmatic from three GEO datasets (GSE104468, GSE165934, and GSE74986). Consistent with this trend, METTL14 was decreased in the lung tissues of OVA-induced asthmatic mice and transforming growth factor-ß1 (TGF-ß1)-stimulated human bronchial epithelial cells (Beas-2B) in this study. Overexpression of METTL14 caused reduction in mesenchymal markers (FN1, N-cad, Col-1 and α-SMA) in TGF-ß1-treated cells, but caused increase in epithelial markers (E-cad), thus inhibiting EMT. Also, METTL14 suppressed the proliferation and migration ability of TGF-ß1-treated Beas-2B cells. Two transcription factors, ETS1 and RBPJ, could both bind to the promoter region of METTL14 and drive its expression. Elevating METTL14 expression could reversed EMT, cell proliferation and migration promoted by ETS1 or RBPJ deficiency. These results indicate that the ETS1/METTL14 and RBPJ/METTL14 transcription axes exhibit anti-EMT, anti-proliferation and anti-migration functions in TGF-ß1-induced bronchial epithelial cells, implying that METTL14 may be considered an alternative candidate target for the treatment of asthma.

Exosomal miR-196b secreted from bronchial epithelial cells chronically exposed to low-dose PM2.5 promotes invasiveness of adjacent and lung cancer cells.

Fine particulate matter (PM2.5) is a risk factor for pulmonary diseases and lung cancer, and inhaled PM2.5 is mainly deposited in the bronchial epithelium. In this study, we investigated the effect of long-term exposure to low-dose PM2.5 on BEAS-2B cells derived from the normal bronchial epithelium. BEAS-2B cells chronically exposed to a concentration of 5 µg/ml PM2.5 for 30 passages displayed the phenotype promoting epithelial-mesenchymal transition (EMT) and cell invasion. Cellular internalization of exosomes (designated PM2.5 Exo) extracted from BEAS-2B cells chronically exposed to low-dose PM2.5 promoted cell invasion in vitro and metastatic potential in vivo. Hence, to identify the key players driving phenotypic alterations, we analyzed microRNA (miRNA) expression profiles in PM2.5 Exo. Five miRNAs with altered expression were selected: miRNA-196b-5p, miR-135a-2-5p, miR-3117-3p, miR-218-5p, and miR-497-5p. miR-196b-5p was the most upregulated in both BEAS-2B cells and isolated exosomes after PM2.5 exposure. In a functional validation study, genetically modified exosomes overexpressing a miR-196b-5p mimic induced an enhanced invasive phenotype in BEAS-2B cells. Conversely, miR-196b-5p inhibition diminished the PM2.5-enhanced EMT and cell invasion. These findings indicate that exosomal miR-196b-5p may be a candidate biomarker for predicting the malignant behavior of the bronchial epithelium and a therapeutic target for inhibiting PM2.5-triggered pathogenesis.