Cultures Of Bronchial Epithelial Cells Research Articles

Influenza A and Respiratory Syncytial Virus Trigger a Cellular Response That Blocks Severe Acute Respiratory Syndrome Virus 2 Infection in the Respiratory Tract.

Multiple viruses cocirculate and contribute to the burden of respiratory disease. Virus-virus interactions can decrease susceptibility to infection and this interference can have an epidemiological impact. As humans are normally exposed to a community of cocirculating respiratory viruses, experimental coinfection studies are necessary to understand the disease mechanisms of multipathogen systems. We aimed to characterize interactions within the respiratory tract between severe acute respiratory syndrome virus 2 (SARS-CoV-2) and 2 major respiratory viruses: influenza A virus (IAV), and respiratory syncytial virus (RSV). We performed single infections and coinfections with SARS-CoV-2 combined with IAV or RSV in cultures of human bronchial epithelial cells. We combined microscopy with quantification of viral replication in the presence or absence of an innate immune inhibitor to determine changes in virus-induced pathology, virus spread, and virus replication. SARS-CoV-2 replication is inhibited by both IAV and RSV. This inhibition is dependent on a functional antiviral response and the level of inhibition is proportional to the timing of secondary viral infection. Infections with other respiratory viruses might provide transient resistance to SARS-CoV-2. It would therefore be expected that the incidence of coronavirus disease 2019 (COVID-19) may decrease during periods of high circulation of IAV and RSV.

Abstract A010: Chemopreventive effects of carvedilol and nebivolol in benzo(a)pyrene-induced transformation of non-tumorous human bronchial epithelial cell

Abstract Lung cancer is among the most common cancers worldwide. The primary risk factor for the development of lung cancer is cigarette smoking and there are a large amount of studies has confirmed the association between smoking and lung cancer. Chemopreventive drug would be beneficial among patients who are in high risk due to chronic exposure to carcinogens. In the previous study of chemopreventive activity of carvedilol, it significantly delayed and reduced skin squamous cell carcinoma development. The aim of the present study was to explore the role of carvedilol and nebivolol in benzo(a)pyrene induced transformation of the non-tumorous human bronchial epithelial cells. To evaluate the effects of carvedilol and nebivolol on chemopreventive activity against BPDE-induced lung carcinogenesis, anchorage-independent growth assay in soft agar was used to determine the degree of malignant transformation of BEAS-2b cells. Before the investigation of carvedilol and nebivolol, the appropriate drug concentration aiming minimum cytotoxicity on normal BEAS-2b cells were determined by MTT assay. The MTT assay was used to measure cellular metabolic activity as an indicator of cytotoxicity. Carvedilol at 10 μM or lower and Nebivolol at 1 μM or lower did not cause significant cytotoxicity. In non-tumorigenic human bronchial epithelial cell culture BEAS-2B vitro assays, carvedilol and nebivolol exert a protective effect against BPDE-indued transformation at non-toxic concentrations in a dose dependent manner. As shown in the figure below, Nebivolol (1 μM and 0.5 μM) and Carvedilol (1 μM and 0.5 μM) both significantly attenuated colony formation compared with BPDE control. However, the anti-transformation mechanism is unknown, further studies of carvedilol and nebivolol are needed to investigate their chemoprevention activity. Citation Format: Carol Lin. Chemopreventive effects of carvedilol and nebivolol in benzo(a)pyrene-induced transformation of non-tumorous human bronchial epithelial cell [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr A010.

Abstract A017: Lung cancer chemoprevention with the β-blocker carvedilol

Abstract Chronic exposure to carcinogens that are present in tobacco smoke is a causative factor for lung carcinogenesis. Although smoking cessation successfully reduced the prevalence of cigarette use in the US, lung cancer risk for current and former smokers remains high, for whom no effective chemopreventive agent currently exists. In the present study, carvedilol, an FDA-approved β-blocker was examined on lung carcinogenesis induced by the tobacco carcinogen benzo(a)pyrene [B(a)P] in vitro and in vivo. In non-tumorigenic human bronchial epithelial cell culture BEAS-2B, carvedilol inhibited benzo(a)pyrene diol epoxide (BPDE)-induced malignant transformation at non-toxic concentrations in a dose-dependent manner. Although β-adrenergic receptors (β-ARs) are expressed in BEAS-2B cells, the anticancer activity of carvedilol is independent of β-blockade since the non-β-blocking R-carvedilol enantiomer also blocked transformation while the β-blockers atenolol (β1-AR selective blocker), ICI-118,551 (β2-AR selective blocker), and propranolol (nonselective blocker) had no effect. Carvedilol’s anti-transformation activity is possibly mediated by aryl hydrocarbon receptor signaling because carvedilol, R- and S-carvedilol all inhibited B(a)P-activated xenobiotic responsive element (XRE) promoter and CYP1A1 mRNA expression. In a B(a)P-induced acute lung toxicity model in CD-1 mice, pretreatment with carvedilol, R- or S-carvedilol (20 mg/kg/day) for 7 days significantly attenuated increased plasma levels of lactate dehydrogenase and malondialdehyde, inflammatory cell infiltration, histopathologic changes, and overexpression of COX-2 in the lung. In a B(a)P-induced lung carcinogenesis model in A/J mice, carvedilol at 3.2 and 20 mg/kg significantly attenuated tumor multiplicity and burden, to a similar degree as the EGFR inhibitor gefitinib. Our study reveals a previously unexplored role for the FDA approved cardiovascular drug carvedilol in the prevention of tobacco carcinogen-associated lung cancer. Citation Format: Ayaz Shahid, Mengbing Chen, Carol Lin, Bradley T. Andresen, Cyrus Parsa, Robert Orlando, Ying Huang. Lung cancer chemoprevention with the β-blocker carvedilol [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr A017.

Capsaicin suppresses ciliary function, while inducing permeability in bronchial epithelial cell cultures of COPD patients.

Take Home Message: Capsaicin modified inflammatory response and caused toxicity in bronchial epithelial cultures from patients with COPD. More importantly, capsaicin decreased ciliary beat frequency and induced epithelial permeability and these effects were partially prevented by formoterol and roflumilast.Tear gas is widely used to halt mass demonstrations. Studies have reported its adverse effects on multiple organ systems; however, its effect on individuals with chronic respiratory diseases and the underlying mechanisms of these effects are unclear. For the first time in the literature, we investigated the effects of capsaicin, the active ingredient of tear gas, on bronchial epithelial cell (BEC) cultures obtained from well-characterized groups of nonsmokers, smokers, and patients with chronic obstructive pulmonary disease (COPD). BEC cultures were incubated with 50-500 μM capsaicin in the absence and presence of formoterol (1μM) and roflumilast (0.1 μM) for 24 h. Ciliary beat frequency (CBF) and transepithelial electrical resistance (TEER) were assessed at T1/4, T1/2, T1, T2, T4, T6, and T24 h, whereas the release of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-8, and lactate dehydrogenase (LDH) was measured at T24 h. Capsaicin (250 µM) significantly decreased CBF of all BEC cultures from T1/4 h to T24 h (p<0.05). Formoterol significantly prevented decreases in CBF induced by capsaicin. Higher concentrations of capsaicin (250-500 μM) significantly reduced TEER of BECs from nonsmokers (T2-T24 h), smokers (T24 h) and COPD patients (T2 and T24 h), which was partially prevented by roflumilast. Capsaicin (500 μM) decreased release of IL-8 (p<0.0001) and GM-CSF (p<0.05) while inducing release of LDH in BECs (p<0.05), and this was more prominent in BEC from patients with COPD. In conclusion, our findings demonstrate that capsaicin can suppress ciliary activity and cytokine release from BECs, induce BEC culture permeability and cellular toxicity and that these effects can be partially prevented by formoterol and roflumilast.

Vegetable glycerin e-cigarette aerosols cause airway inflammation and ion channel dysfunction.

Vegetable glycerin (VG) and propylene glycol (PG) serve as delivery vehicles for nicotine and flavorings in most e-cigarette (e-cig) liquids. Here, we investigated whether VG e-cig aerosols, in the absence of nicotine and flavors, impact parameters of mucociliary function in human volunteers, a large animal model (sheep), and air-liquid interface (ALI) cultures of primary human bronchial epithelial cells (HBECs). We found that VG-containing (VG or PG/VG), but not sole PG-containing, e-cig aerosols reduced the activity of nasal cystic fibrosis transmembrane conductance regulator (CFTR) in human volunteers who vaped for seven days. Markers of inflammation, including interleukin-6 (IL6), interleukin-8 (IL8) and matrix metalloproteinase-9 (MMP9) mRNAs, as well as MMP-9 activity and mucin 5AC (MUC5AC) expression levels, were also elevated in nasal samples from volunteers who vaped VG-containing e-liquids. In sheep, exposures to VG e-cig aerosols for five days increased mucus concentrations and MMP-9 activity in tracheal secretions and plasma levels of transforming growth factor-beta 1 (TGF-β1). In vitro exposure of HBECs to VG e-cig aerosols for five days decreased ciliary beating and increased mucus concentrations. VG e-cig aerosols also reduced CFTR function in HBECs, mechanistically by reducing membrane fluidity. Although VG e-cig aerosols did not increase MMP9 mRNA expression, expression levels of IL6, IL8, TGFB1, and MUC5AC mRNAs were significantly increased in HBECs after seven days of exposure. Thus, VG e-cig aerosols can potentially cause harm in the airway by inducing inflammation and ion channel dysfunction with consequent mucus hyperconcentration.

Nearly Complete Genome Sequences of 12 Types of Human Rhinoviruses Isolated from Pediatric Inpatients in Fukushima, Japan.

ABSTRACTWe reported nearly complete genomic sequences of 12 serotypes of human rhinoviruses (HRVs) isolated from pediatric inpatients in Fukushima, Japan using an air-liquid interface culture of human bronchial tracheal epithelial cells. We found that various serotypes of HRV circulated locally and simultaneously from 2018 to 2021.

Ten Nearly Complete Genome Sequences of Human Orthorubulavirus 4 Isolated from Pediatric Inpatients in Fukushima, Japan.

ABSTRACTWe report 10 nearly complete genomic sequences of human orthorubulavirus 4, also called human parainfluenza virus 4 (HPIV4), isolated from pediatric inpatients with respiratory infections in Fukushima, Japan, by using an air-liquid interface culture of human bronchial and tracheal epithelial cells.

Designing Self-floating Anisotropic Macroporous Hydrogel by Step Emulsification and Buoyancy-assisted Microfluidics

Macroporous hydrogel with self-floating properties shows promising applications in gastric drug delivery, water purification and air–liquid interface cell culture. Microfluidic bubble templating is an emerging routine to produce macroporous hydrogel. However, current methods are in lack of the control over the anisotropy and porosity. Here, we describe new developments for the buoyancy-assisted microfluidic fabrication of anisotropic hydrogel products by templating from bubbles formed using step emulsification. The step emulsification method generates bubbles with exceptional precision which enables convenient tailoring the internal porosity of the hydrogel particles. Further design over the device structure and the buoyancy during the drop formation produces irregular hydrogel products such as macroporous fibers and core/shell beads. The anisotropic hydrogel beads provide pressure-responsive swimming behaviors and controllable release of the carried cargos. They are proved to be competent as carriers for culture of bronchial epithelial cells on air–liquid interfaces.

Allergic inflammation in lungs and nasal epithelium of rat model is regulated by tissue-specific miRNA expression

IntroductionAtopic asthma and allergic rhinitis are common chronic inflammatory diseases affecting lower airways and nasal mucosa, respectively. Several reports demonstrated frequent co-occurrence of these two diseases, however, the exact molecular mechanism has not been described. The present study aimed to investigate if small non-coding RNA might be responsible for the co-occurrence of asthma and allergic rhinitis in an animal model of allergic airway inflammation. Materials and methodsAs an in vivo model of allergic airway inflammation, we used Brown Norway rats exposed intranasally to house dust mite (HDM). Histological analysis, total IgE concentration, eosinophil counts and iNOS gene expression were determined to confirm inflammatory changes. Small RNA sequencing in the lung tissue and nasal epithelium was performed with TruSeq Small RNA Library Preparation Kit and analyzed using the BaseSpace tool. Validation of sequencing results was performed using qPCR. To assess the functional role of hsa-miR-223–3p, we transfected normal human bronchial epithelial (NHBE) cells with specific LNA-inhibitor and measured phosphorylated protein level of NF-kB with ELISA. Expression analysis of NF-kB pathway-related genes was performed using qPCR with SYBR Green and analyzed in DataAssist v3.01. Statistical analysis were done with STATISTICA version 13. ResultsWe found 9 miRNA genes differentially expressed in the lungs of allergic rats. In nasal epithelium, only rno-miR-184 was upregulated in animals exposed to HDM. Validation with qPCR confirmed increased expression only for rno-miR-223–3p in the lungs from allergic rats. The expression of this miRNA was also increased in normal bronchial epithelial ALI cell culture stimulated with IL-13, but not in cells cultured in monolayer due to the low mRNA level of IL13RA1 and IL13RA2. Transfecting NHBE cells with hsa-miR-223–3p inhibitor increased the amount of phosphorylated NF-kB protein level and expression of MUC5AC, CCL24 and TSLP genes. ConclusionsThese findings suggest that miRNAs that regulate allergic inflammation in the lungs and nasal epithelium are specific for upper and lower airways. Furthermore, our study provides new insight on the role of hsa-miR-223–3p, that via targeting NF-kB signaling pathway, regulates the expression of MUC5AC, CCL24 and TSLP. Taken together, our study suggests that miR-223–3p is a regulator of allergic inflammation and could potentially be used to develop novel and targeted therapy for asthma.

Epithelial 3D-spheroids as a tool to study air pollutant-induced lung pathology.

Cigarette smoke (CS) and air pollutants (AP) activate pathological processes in bronchial epithelial cells resulting in lung function decline which severely impacts human health. Knowledge about the molecular mechanism(s) by which CS and AP induce pathology is limited. Our previous studies in 2D cultures of human bronchial epithelial (BEAS-2B) cells showed that CS exposure activates transforming growth factor-β1 (TGF-β1) release and signaling. Furthermore, CS exposure reduced the expression of E-cadherin, which was prevented by applying a TGF-β1 neutralizing antibody. Exposure of BEAS-2B cells cultured in 2D to diesel exhaust particles (DEP) increased TGF-β1 protein expression and reduced the expression of epithelial cell markers, whereas mesenchymal markers are upregulated. Conventional 2D cell culture may, however, not fully reflect the physiology of bronchial epithelial cells in vivo. To simulate the in vivo situation more closely we cultured the bronchial epithelial cells in a 3D environment in the current study. Treatment of epithelial spheroids with TGF-β resulted in reduced E-cadherin and increased collagen I expression, indicating the activation of epithelial-to-mesenchymal transition (EMT). Similarly, exposure of spheroids to DEP induced and EMT-like phenotype. Collectively, our data indicate AP induces an EMT-like phenotype of BEAS-2B cells in 3D spheroid cultures. This opens new avenues for drug development for the treatment of lung diseases induced by AP. The 3D spheroid cell culture is a novel, innovative and physiologically relevant model for culturing a variety of cells. It is a versatile tool for both high-throughput studies and for identifying molecular mechanisms involved in bronchial epithelial cell (patho)physiology.

Influence of culture expansion medium on human bronchial epithelium composition and function

Primary culture of human bronchial epithelial cells in air/liquid interface (ALI) is a validated in vitro model, which provides fully differentiated and pseudostratified bronchial epithelium and allows to analyze its functions in different respiratory diseases. However, the potential impact of the culture medium on the structure and the metabolism of this reconstituted epithelium is currently underestimated. Epithelial cells were grown either in PneumaCult Ex (PC Ex) or PneumaCult Ex+ (PC Ex + ) medium (StemCell, Vancouver, Canada). After the expansion phase, cells were differentiated in PneumaCult ALI medium. Analyses were performed during the expansion phase, and at day 0 (D0), D7, D14, D21 and D28 of the differentiation process. Pictures of the cell morphology were taken, immunostaining were carried out on cytocentrifuged cells, and culture supernatants were stored for subsequent analyses. At D28 of differentiation, bronchial epithelium was challenged with Poly I:C or TNF-α. The cytokine secretion in culture media or apical lavages, and the expression of mRNA and intra-cellular protein were assessed. PC Ex+ medium provided a higher cell yield than PC Ex. Morphology was found to be different, as PC Ex + -cultured cells formed clusters. At early and differentiated stage, cells cultured in PC Ex medium expressed specific epithelial and mesenchymal markers (pan-cytokeratin and vimentin, respectively), while cells in PC Ex+ mainly expressed the epithelial marker. Our preliminary results showed differences in terms of cellular yield and epithelial-mesenchymal cell features, depending on the culture medium used for cellular expansion. The influence of the expansion medium on cell subtypes during the differentiation steps is under investigation. In the near future, we will compare the release of cell mediators at steady state and after stimulation to better understand the effect of culture medium on the functional responses of epithelial cells.

Thirteen Nearly Complete Genome Sequences of Human Bocavirus 1 Isolated from Pediatric Inpatients in Fukushima, Japan.

ABSTRACTWe report 13 genomic sequences of human bocavirus 1 isolated from pediatric inpatients in Fukushima, Japan, using an air-liquid interface culture of human bronchial tracheal epithelial cells. This work suggests the endemic circulation of a human bocavirus variant with a unique amino acid signature in Fukushima.

Human Bronchial Epithelial Cell Culture Models for Cigarette Smoke and Vaping Studies.

Despite the continuing public health efforts to stop or reduce smoking, cigarette smoke use remains popular in the youth and adult population. A recent surge in the use of electronic cigarette and vaping products has created another major health challenge in public health. There is an urgent need to use physiologically relevant models to study the health effect of smoking or vaping in human subjects. Airway diseases such as bronchitis (Landman et al., CMAJ 191:E1321-E1331, 2019; Goniewicz, et al. Harm Reduct J 17:91, 2020; Xie et al., JAMA Netw Open 3:e2020816, 2020) have been described in people who smoke, vape, or both. Here, we will describe methods to collect, expand, and culture human airway epithelial cells from endobronchial brushings and expose these cells cultured at the air-liquid interface to cigarette smoke or electronic cigarette vapor.

Interferon-Lambda Intranasal Protection and Differential Sex Pathology in a Murine Model of SARS-CoV-2 Infection.

ABSTRACTOutbreaks of emerging viral pathogens like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are a major medical challenge. There is a pressing need for antivirals that can be rapidly deployed to curb infection and dissemination. We determined the efficacy of interferon lambda-1 (IFN-λ) as a broad-spectrum antiviral agent to inhibit SARS-CoV-2 infection and reduce pathology in a mouse model of disease. IFN-λ significantly limited SARS-CoV-2 production in primary human bronchial epithelial cells in culture. Pretreatment of human lung cells with IFN-λ completely blocked infectious virus production, and treatment with IFN-λ at the time of infection inhibited virus production more than 10-fold. To interrogate the protective effects of IFN-λ in response to SARS-CoV-2 infection, transgenic mice expressing the human angiotensin-converting enzyme 2 (ACE-2) were tested. One dose of IFN-λ administered intranasally was found to reduce animal morbidity and mortality. Our study with SARS-CoV-2 also revealed a sex differential in disease outcome. Male mice had higher mortality, reflecting the more severe symptoms and mortality found in male patients infected with SARS-CoV-2. The results indicate that IFN-λ potentially can treat early stages of SARS-CoV-2 infection and decrease pathology, and this murine model can be used to investigate the sex differential documented in COVID-19.

Inhaled gene therapy of preclinical muco-obstructive lung diseases by nanoparticles capable of breaching the airway mucus barrier

IntroductionInhaled gene therapy of muco-obstructive lung diseases requires a strategy to achieve therapeutically relevant gene transfer to airway epithelium covered by particularly dehydrated and condensed mucus gel layer. Here, we...

Kallikrein-related peptidase 5 contributes to the remodeling and repair of bronchial epithelium.

Inflammation, oxidative stress, and protease/protease inhibitor imbalance with excessive production of proteases are factors associated with pathogenesis of the chronic obstructive pulmonary disease (COPD). In this study, we report that kallikrein-related peptidase 5 (KLK5) is a crucial protease involved in extracellular matrix (ECM) remodeling and bronchial epithelial repair after injury. First, we showed that KLK5 degrades the basal layer formed by culture of primary bronchial epithelial cells from COPD or non-COPD patients. Also, exogenous KLK5 acted differently on BEAS-2B cells already engaged in epithelial-to-mesenchymal transition (EMT) or on 16HBE 14o- cells harboring epithelial characteristics. Indeed, by inducing EMT, KLK5 reduced BEAS-2B cell adherence to the ECM. This effect, neutralized by tissue factor pathway inhibitor 2, a kunitz-type serine protease inhibitor, was due to a direct proteolytic activity of KLK5 on E-cadherin, β-catenin, fibronectin, and α5β1 integrin. Thus, KLK5 may strengthen EMT mechanisms and promote the migration of cells by activating the mitogen-activated protein kinase signaling pathway required for this function. In contrast, knockdown of endogenous KLK5 in 16HBE14o- cells, accelerated wound healing repair after injury, and exogenous KLK5 addition delayed the closure repair. These data suggest that among proteases, KLK5 could play a critical role in airway remodeling events associated with COPD during exposure of the pulmonary epithelium to inhaled irritants or smoking and the inflammation process.

A Potential Role of the CD47/SIRPalpha Axis in COVID-19 Pathogenesis.

The coronavirus SARS-CoV-2 is the cause of the ongoing COVID-19 pandemic. Most SARS-CoV-2 infections are mild or even asymptomatic. However, a small fraction of infected individuals develops severe, life-threatening disease, which is caused by an uncontrolled immune response resulting in hyperinflammation. However, the factors predisposing individuals to severe disease remain poorly understood. Here, we show that levels of CD47, which is known to mediate immune escape in cancer and virus-infected cells, are elevated in SARS-CoV-2-infected Caco-2 cells, Calu-3 cells, and air−liquid interface cultures of primary human bronchial epithelial cells. Moreover, SARS-CoV-2 infection increases SIRPalpha levels, the binding partner of CD47, on primary human monocytes. Systematic literature searches further indicated that known risk factors such as older age and diabetes are associated with increased CD47 levels. High CD47 levels contribute to vascular disease, vasoconstriction, and hypertension, conditions that may predispose SARS-CoV-2-infected individuals to COVID-19-related complications such as pulmonary hypertension, lung fibrosis, myocardial injury, stroke, and acute kidney injury. Hence, age-related and virus-induced CD47 expression is a candidate mechanism potentially contributing to severe COVID-19, as well as a therapeutic target, which may be addressed by antibodies and small molecules. Further research will be needed to investigate the potential involvement of CD47 and SIRPalpha in COVID-19 pathology. Our data should encourage other research groups to consider the potential relevance of the CD47/ SIRPalpha axis in their COVID-19 research.

Impaired Ciliary Beat Frequency and Ciliogenesis Alteration during Airway Epithelial Cell Differentiation in COPD.

Chronic obstructive pulmonary disease (COPD) is a frequent respiratory disease. However, its pathophysiology remains partially elucidated. Epithelial remodeling including alteration of the cilium is a major hallmark of COPD, but specific assessments of the cilium have been rarely investigated as a diagnostic tool in COPD. Here we explore the dysregulation of the ciliary function (ciliary beat frequency (CBF)) and differentiation (multiciliated cells formation in air-liquid interface cultures) of bronchial epithelial cells from COPD (n = 17) and non-COPD patients (n = 15). CBF was decreased by 30% in COPD (11.15 +/− 3.37 Hz vs. 7.89 +/− 3.39 Hz, p = 0.037). Ciliary differentiation was altered during airway epithelial cell differentiation from COPD patients. While the number of multiciliated cells decreased (p < 0.005), the number of primary ciliated cells increased (p < 0.05) and primary cilia were shorter (p < 0.05). Altogether, we demonstrate that COPD can be considered as a ciliopathy through both primary non-motile cilia modifications (related to airway epithelial cell repair and remodeling) and motile cilia function impairment (associated with decrease sputum clearance and clinical respiratory symptoms). These observations encourage considering cilia-associated features in the complex COPD physiopathology and highlight the potential of cilia-derived biomarkers for diagnosis.

Epithelial–stromal cell interactions and extracellular matrix mechanics drive the formation of airway-mimetic tubular morphology in lung organoids

SummaryComplex human airway cellular organization where extracellular matrix (ECM) and epithelial and stromal lineages interact present challenges for organ study in vitro. Current in vitro lung models that focus on the lung epithelium do not represent complex airway morphology and cell-ECM interactions seen in vivo. Models including stromal populations often separate them via a semipermeable barrier precluding cell–cell interaction or the effect of ECM mechanics. We investigated the effect of stromal cells on basal epithelial cell-derived bronchosphere structure and function through a triple culture of human bronchial epithelial, lung fibroblast, and airway smooth muscle cells. Epithelial–stromal cross-talk resulted in epithelial cell-driven branching tubules with stromal cells surrounding epithelial cells termed bronchotubules. Agarose– Matrigel scaffold (Agrigel) formed a mechanically tuneable ECM, with adjustable viscoelasticity and stiffness enabling long-term tubule survival. Bronchotubule models may enable research into how epithelial–stromal cell and cell–ECM communication drive tissue patterning, repair, and development of disease.

Long-term modulation of airway remodelling in severe asthma following bronchial thermoplasty.

Bronchial thermoplasty is a mechanical therapeutic intervention that has been advocated as an effective treatment option for severe asthma. The mechanism is promoted as being related to the attenuation of airway smooth muscle which has been shown to occur in the short-term. However, long-term studies of the effects of bronchial thermoplasty on airway remodeling are few with only limited assessment of airway remodeling indices. To evaluate the effect of bronchial thermoplasty on (a) airway epithelial and smooth muscle cells in culture, and (b), airway remodeling in patients with severe asthma who have been prescribed bronchial thermoplasty up to 12-months post-treatment. The distribution of heat within the airway by bronchial thermoplasty was assessed in a porcine model. Culture of human airway smooth muscle cells and bronchial epithelial cells evaluated the impact of thermal injury. Histological evaluation and morphometric assessment were performed on bronchial biopsies obtained from severe asthma patients at baseline, 6-weeks, and 12-months following bronchial thermoplasty. Bronchial thermoplasty resulted in heterogenous heating of the airway wall. Airway smooth muscle cell cultures sustained thermal injury, whilst bronchial epithelial cells were relatively resistant to heat. Airway smooth muscle and neural bundles were significantly reduced at 6-weeks and 12-months post-treatment. At 6-weeks post treatment, submucosal collagen was reduced, and vessel density increased, with both indices returning to baseline at 12-months. Goblet cell numbers, submucosal gland area and subbasement membrane thickness, were not significantly altered at any timepoint examined. Bronchial thermoplasty primarily affects airway smooth muscle and nerves with the effects still present at 12-months post-treatment.