Caspase-11 and AIM2 inflammasome are involved in smoking-induced COPD and lung adenocarcinoma

Abstract

Cigarette smoking is the leading risk factor for COPD and lung cancer establishment. Epidemiologically, COPD patients are 6.35 times more likely to develop lung cancer.

To mimic COPD, we exposed mice to nose-only cigarette smoke and used human samples of lung adenocarcinoma patients according to the smoking and COPD status.

Smoking C57Bl/6N mice had higher enlargement of alveoli, deposition of collagen and mucus production, associated to the release of IL-1-like cytokines, such as IL-1α and IL-1β at early time points and IL-18 at later time points. AIM2 expression was higher in lung recruited dendritic cells and macrophages in smoking mice, associated to the activation of caspase-11, rather than caspase-1. In support,129Sv mice, which are dysfunctional for caspase-11, had lower collagen deposition and mucus production, associated to lower release of IL-1-like and fibrotic TGFβ. Interestingly, higher expression of AIM2 in non-cancerous tissue of smoking COPD adenocarcinoma patients was correlated to a higher hazard ratio of poor survival rate than in patients who presented lower levels of AIM2.

We found that AIM2 inflammasome is at the crossroad between COPD and lung cancer in that its higher presence is correlated to lower survival rate of smoking COPD adenocarcinoma patients.