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E-cigarettes are proposed as an alternative to smoking and as nicotine replacement therapy. There is confusion around their safety stemming from contradictory findings across multiple studies. Patients with COPD find it difficult to quit smoking and as such e-cigarettes are an attractive option. The aim of this study was to determine the inflammatory response to e-cigarettes in cells from people with and without COPD under realistic physiological conditions. Primary human airway smooth muscle cells were isolated from explanted and resected lung tissue from COPD patients and smokers without COPD. Cells were stimulated with increasing concentrations of 18mg/ml nicotine and 0mg/ml nicotine (tobacco and menthol flavoured, Vaper Empire) E-vapour extract for 24 hours. An MTT assay was performed to determine cytotoxicity and ELISA was used to assess IL-6 and CXCL8 production. Tobacco and Menthol (18mg/ml nicotine, 0mg/ml nicotine) E-vapour extracts were cytotoxic to cells (n=9-14, p≤0.0001), cytotoxicity of E-vapour was increased in aerosols created at higher temperatures. All 4 E-vapour extracts stimulated CXCL8 production compared to unstimulated controls (n=14, p E-cigarettes have the potential to contribute to the pathology of COPD. Cytotoxicity can cause cell death and ineffective repair, as seen in both the airways and parenchyma in COPD. Our data suggests that COPD patients should not use them as a smoking cessation aid or cigarette replacement.

Airway remodeling is a hallmark feature of individuals with COPD. Increased airway smooth muscle (ASM) mass, and ASM thickness is correlated with severity of the disease and has been described to negatively impact lung function in COPD. Current medications control inflammation and reverse airway obstruction effectively yet have limited effect on remodeling. Apoptosis signal-regulating kinase 1 (ASK1) is a ubiquitously expressed MAPK kinase kinase (MAP3K), activated by various stress stimuli, including ROS, TNF-α, and LPS. ASK1 affects multiple cellular functions, including survival, differentiation, and the innate immune response and has been reported to be involved in the pathogenesis of various human diseases. However, no reported study has demonstrated a role for ASK1 in airway remodeling. In this study we aimed to determine the effects of ASK1 inhibition on ASM growth and pro-mitogenic signaling. We found expression of ASK1 on human lung tissue and primary human ASM cells. Pre-treatment of human ASM cells with potent and orally available ASK1 inhibitor, TCASK10 resulted in a dose-dependent reduction in mitogen (FBS, PDGF and EGF)-induced ASM growth as measured by CyQuant assay. Furthermore, the effectiveness of this pharmacological inhibition was established and replicated in gene silencing experiments where ASK1 siRNA inhibited mitogen-induced human ASM cell growth. Immunoblotting revealed that the anti-mitogenic effect of ASK1 inhibition or silencing is mediated by JNK-signaling pathway. Collectively, these findings establish the anti-mitogenic effect of ASK1 inhibition and identify a novel pathway that can be targeted to reduce or prevent excessive ASM mass in COPD.

Introduction: Obesity is an important risk factor for developing severe asthma. Dietary fatty acids, increased in the serum of obese people, activate systemic innate immune responses. Furthermore, we have shown that a single high fat meal increases airway inflammation and impairs bronchodilator recovery in asthma. Aims: To investigate whether dietary fatty acids directly cause inflammation and/or synergise with obesity induced cytokines. Methods: Primary human pulmonary fibroblasts were incubated with BSA-conjugated fatty acids for 24hr, before stimulation with TNFα for another 24hr. IL6 and CXCL8 release was measured using ELISA. IL6 acts as a general marker for inflammation and CXCL8 is a potent neutrophilic chemoattractant. The following ω-6 and 3 polyunsaturated fatty acids were used: arachidonic acid (AA) and docosahexaenoic acid (DHA) (1, 10, 100µM). Results: AA induced substantial IL6 (n=11, P Conclusion: These findings suggest that dietary fatty acids are important modulators of inflammatory responses and that there is an interaction between fatty acids and TNFα, resulting in a synergetic inflammatory response in pulmonary fibroblasts. This could indicate that obese asthmatics compared to lean individuals, are more prone to airway inflammation after a high fat meal.