Impact of e-cigarette aerosol on primary human alveolar epithelial type 2 cells.

Electronic cigarettes (e-cigarettes) are designed to simulate combustible cigarette smoking and to aid in smoking cessation. Although the number of e-cigarette users has been increasing, the potential health impacts and biological effects of e-cigarettes are still not fully understood. Previous research has focused on the biological effects of e-cigarettes on lung cancer cell lines and distal airway epithelial cells; however, there have been few published studies on the effect of e-cigarettes on primary lung alveolar epithelial cells. The primary purpose of this study was to investigate the direct effect of e-cigarette aerosol on primary human lung alveolar epithelial type 2 (AT2) cells, both alone and in the presence of viral infection. The Melo-3 atomizer caused direct AT2 cell toxicity, whereas the more popular Juul pod's aerosol did not have a detectable cytotoxic effect on AT2 cells. Juul nicotine aerosol also did not increase short-term susceptibility to viral infection. However, 3 days of exposure upregulated genes central to the generation of reactive oxygen species, lipid peroxidation, and carcinogen metabolism and downregulated key innate immune system genes related to cytokine and chemokine signaling. These findings have implications for the potentially injurious impact of long-term use of popular low-power e-cigarette pods on the human alveolar epithelium. Gene expression data might be an important endpoint for evaluating the potential harmful effects of vaping devices that do not cause overt toxicity.

Chronic lung allograft dysfunction small airways reveal a lymphocytic inflammation gene signature.

Chronic lung allograft dysfunction (CLAD) is the major barrier to long-term survival following lung transplantation, and new mechanistic biomarkers are needed. Lymphocytic bronchitis (LB) precedes CLAD and has a defined molecular signature. We hypothesized that this LB molecular signature would be associated with CLAD in small airway brushings independent of infection. We quantified RNA expression from small airway brushings and transbronchial biopsies, using RNAseq and digital RNA counting, respectively, for 22 CLAD cases and 27 matched controls. LB metagene scores were compared across CLAD strata by Wilcoxon rank sum test. We performed unbiased host transcriptome pathway and microbial metagenome analysis in airway brushes and compared machine-learning classifiers between the two tissue types. This LB metagene score was increased in CLAD airway brushes (p = .002) and improved prediction of graft failure (p = .02). Gene expression classifiers based on airway brushes outperformed those using transbronchial biopsies. While infection was associated with decreased microbial alpha-diversity (p ≤ .04), neither infection nor alpha-diversity was associated with LB gene expression. In summary, CLAD was associated with small airway gene expression changes not apparent in transbronchial biopsies in this cohort. Molecular analysis of airway brushings for diagnosing CLAD merits further examination in multicenter cohorts.

The ex vivo perfused human lung is resistant to injury by high-dose S. pneumoniae bacteremia.

Few patients with bacteremia from a nonpulmonary source develop acute respiratory distress syndrome (ARDS). However, the mechanisms that protect the lung from injury in bacteremia have not been identified. We simulated bacteremia by adding Streptococcus pneumoniae to the perfusate of the ex vivo perfused human lung model. In contrast to a pneumonia model in which bacteria were instilled into the distal air spaces of one lobe, injection of high doses of S. pneumoniae into the perfusate was not associated with alveolar epithelial injury as demonstrated by low protein permeability of the alveolar epithelium, intact alveolar fluid clearance, and the absence of alveolar edema. Unexpectedly, the ex vivo human lung rapidly cleared large quantities of S. pneumoniae even though the perfusate had very few intravascular phagocytes and lacked immunoglobulins or complement. The bacteria were cleared in part by the small number of neutrophils in the perfusate, alveolar macrophages in the airspaces, and probably by interstitial pathways. Together, these findings identify one mechanism by which the lung and the alveolar epithelium are protected from injury in bacteremia.

Lung Microbiota Is Related to Smoking Status and to Development of Acute Respiratory Distress Syndrome in Critically Ill Trauma Patients.

RATIONALE: Cigarette smoking is associated with increased risk of acute respiratory distress syndrome (ARDS) in patients after severe trauma; however, the mechanisms underlying this association are unknown. OBJECTIVES: To determine whether cigarette smoking contributes to ARDS development after trauma by altering community composition of the lung microbiota. METHODS: We studied the lung microbiota of mechanically ventilated patients admitted to the ICU after severe blunt trauma. To do so, we used 16S ribosomal RNA gene amplicon sequencing of endotracheal aspirate samples obtained on ICU admission (n = 74) and at 48 hours after admission (n = 30). Cigarette smoke exposure (quantified using plasma cotinine), ARDS development, and other clinical parameters were correlated with lung microbiota composition. MEASUREMENTS AND MAIN RESULTS: Smoking status was significantly associated with lung bacterial community composition at ICU admission (P = 0.007 by permutational multivariate ANOVA [PERMANOVA]) and at 48 hours (P = 0.03 by PERMANOVA), as well as with significant enrichment of potential pathogens, including Streptococcus, Fusobacterium, Prevotella, Haemophilus, and Treponema. ARDS development was associated with lung community composition at 48 hours (P = 0.04 by PERMANOVA) and was characterized by relative enrichment of Enterobacteriaceae and of specific taxa enriched at baseline in smokers, including Prevotella and Fusobacterium. CONCLUSIONS: After severe blunt trauma, a history of smoking is related to lung microbiota composition, both at the time of ICU admission and at 48 hours. ARDS development is also correlated with respiratory microbial community structure at 48 hours and with taxa that are relatively enriched in smokers at ICU admission. The data derived from this pilot study suggest that smoking-related changes in the lung microbiota could be related to ARDS development after severe trauma.

Workshop-based learning and networking: a scalable model for research capacity strengthening in low- and middle-income countries.

Science education and research have the potential to drive profound change in low- and middle-income countries (LMICs) through encouraging innovation, attracting industry, and creating job opportunities. However, in LMICs, research capacity is often limited, and acquisition of funding and access to state-of-the-art technologies is challenging. The Alliance for Global Health and Science (the Alliance) was founded as a partnership between the University of California, Berkeley (USA) and Makerere University (Uganda), with the goal of strengthening Makerere University's capacity for bioscience research. The flagship program of the Alliance partnership is the MU/UCB Biosciences Training Program, an in-country, hands-on workshop model that trains a large number of students from Makerere University in infectious disease and molecular biology research. This approach nucleates training of larger and more diverse groups of students, development of mentoring and bi-directional research partnerships, and support of the local economy. Here, we describe the project, its conception, implementation, challenges, and outcomes of bioscience research workshops. We aim to provide a blueprint for workshop implementation, and create a valuable resource for bioscience research capacity strengthening in LMICs.

The sputum transcriptome better predicts COPD exacerbations after the withdrawal of inhaled corticosteroids than sputum eosinophils.

INTRODUCTION: Continuing inhaled corticosteroid (ICS) use does not benefit all patients with COPD, yet it is difficult to determine which patients may safely sustain ICS withdrawal. Although eosinophil levels can facilitate this decision, better biomarkers could improve personalised treatment decisions. METHODS: We performed transcriptional profiling of sputum to explore the molecular biology and compared the predictive value of an unbiased gene signature versus sputum eosinophils for exacerbations after ICS withdrawal in COPD patients. RNA-sequencing data of induced sputum samples from 43 COPD patients were associated with the time to exacerbation after ICS withdrawal. Expression profiles of differentially expressed genes were summarised to create gene signatures. In addition, we built a Bayesian network model to determine coregulatory networks related to the onset of COPD exacerbations after ICS withdrawal. RESULTS: In multivariate analyses, we identified a gene signature (LGALS12, ALOX15, CLC, IL1RL1, CD24, EMR4P) associated with the time to first exacerbation after ICS withdrawal. The addition of this gene signature to a multiple Cox regression model explained more variance of time to exacerbations compared to a model using sputum eosinophils. The gene signature correlated with sputum eosinophil as well as macrophage cell counts. The Bayesian network model identified three coregulatory gene networks as well as sex to be related to an early versus late/nonexacerbation phenotype. CONCLUSION: We identified a sputum gene expression signature that exhibited a higher predictive value for predicting COPD exacerbations after ICS withdrawal than sputum eosinophilia. Future studies should investigate the utility of this signature, which might enhance personalised ICS treatment in COPD patients.

Cystic Fibrosis Lung Transplant Recipients Have Suppressed Airway Interferon Responses during Pseudomonas Infection.

Lung transplantation can be lifesaving in end-stage cystic fibrosis (CF), but long-term survival is limited by chronic lung allograft dysfunction (CLAD). Persistent upper airway Pseudomonas aeruginosa (PsA) colonization can seed the allograft. While de novo PsA infection is associated with CLAD in non-CF recipients, this association is less clear for CF recipients experiencing PsA recolonization. Here, we evaluate host and pathogen contributions to this phenomenon. In the context of PsA infection, brushings from the airways of CF recipients demonstrate type 1 interferon gene suppression. Airway epithelial cell (AEC) cultures demonstrate similar findings in the absence of pathogens or immune cells, contrasting with the pre-transplant CF AEC phenotype. Type 1 interferon promoters are relatively hypermethylated in CF AECs. CF subjects in this cohort have more mucoid PsA, while non-CF PsA subjects have decreased microbiome α diversity. Peri-transplant protocols may benefit from consideration of this host and microbiome equilibrium.

Clinical, genomic, and metagenomic characterization of oral tongue squamous cell carcinoma in patients who do not smoke.

BACKGROUND: Evidence suggests the incidence of oral tongue squamous cell carcinoma is increasing in young patients, many who have no history of tobacco use. METHODS: We clinically reviewed 89 patients with oral tongue cancer. Exomic sequencing of tumor DNA from 6 nonsmokers was performed and compared to previously sequenced cases. RNA from 20 tumors was evaluated by massively parallel sequencing to search for potentially oncogenic viruses. RESULTS: Non-smokers (53 of 89) were younger than smokers (36 of 89; mean, 50.4 vs 61.9 years; p < .001), and seemed more likely to be women (58.5% vs 38.9%; p = .069). Nonsmokers had fewer TP53 mutations (p = .02) than smokers. No tumor-associated viruses were detected. CONCLUSION: The young age of nonsmoking patients with oral tongue cancer and fewer TP53 mutations suggest a viral role in this disease. Our efforts to identify such a virus were unsuccessful. Further studies are warranted to elucidate the drivers of carcinogenesis in these patients.