E-cigarette vapour induces cellular senescence in primary lung fibroblasts and may contribute to lung pathology

Cellular senescence has been recognized to play a role in COPD pathophysiology. Non-aerosolized E-liquid treatment of a lung fibroblast foetal cell line resulted in cellular senescence induction, but this has not been assessed using E-vapour exposure and using primary lung fibroblasts. Therefore, we investigated whether E-vapour exposure induces cellular senescence in primary human lung fibroblasts and whether this affects their tissue repair function. Primary human lung fibroblasts were stimulated with E-cigarette vapour extracts, and cigarette smoke extract (CSE) and Paraquat (PQ) as positive controls. IL-8 secretion was measured to confirm a stimulatory response. Multiple senescence markers (p16, p21, SA-{beta}-gal, and proliferation) were assessed and the tissue repair function was assessed using a scratch assay. Finally, we tried to validate our findings in an E-cigarette-exposed mouse model. Upon stimulation with CSE, PQ, and E-vapour extracts, cellular senescence was induced, which seemed dose-dependent and nicotine-independent. E-vapour-induced senescence resulted in an impaired tissue repair function. No significant difference was observed in the E-cigarette-exposed mouse model. In this study, we identify E-cigarette vapours potential to induce cellular senescence in primary human lung fibroblasts and that this affects their tissue repair function, which further adds to the identified risks of E-cigarette use.