Resveratrol Blocks Cigarette Smoke Cell Death via miR-200a/Nrf2 Pathway

Chronic obstructive pulmonary disease (COPD) is the third leading cause of disease-related death globally, with cigarette smoke (CS) as its primary driver. CS triggers oxidative stress and pyroptosis—an inflammatory programmed cell death—in bronchial epithelial cells via NLRP3 inflammasome activation. Despite growing interest in natural compounds, the precise mechanism by which resveratrol might counter these effects remained unclear. This study set out to fill that gap by mapping the molecular pathway connecting resveratrol to pyroptosis suppression in COPD-relevant models.

The research team exposed three human bronchial epithelial cell lines (BEAS-2B, 16HBE, and A549) to 5% cigarette smoke extract (CSE) for 24 hours, with or without 20 µM resveratrol pretreatment. They measured reactive oxygen species (ROS) using DCFH-DA fluorescence, quantified oxidative stress markers (SOD, MDA, GSH/GSSG), assessed pyroptosis proteins (NLRP3, caspase-1, GSDMD, TXNIP) by Western blot and qRT-PCR, and measured inflammatory cytokines (IL-1β) by ELISA. Mechanistic experiments included siRNA knockdown of Nrf2, Keap1, and TXNIP, as well as dual-luciferase reporter assays to confirm miR-200a binding to the Keap1 3′-UTR. Molecular docking with the GOLD program visualized resveratrol's interaction with Keap1. In vivo, male C57BL/6J mice were exposed to 20 cigarettes/day, 5 days/week for 6 months, with resveratrol delivered intratracheally (20 mg/kg) before each exposure. Lung function was assessed by whole-body plethysmography.

CSE robustly induced ROS accumulation, elevated MDA, reduced SOD and GSH, and activated the TXNIP/NLRP3/caspase-1/GSDMD pyroptotic axis alongside IL-1β secretion. Resveratrol pretreatment significantly reversed all these effects. Crucially, resveratrol upregulated miR-200a expression; miR-200a directly targeted the 3′-UTR of Keap1 mRNA, reducing Keap1 protein levels and thereby freeing Nrf2 to translocate to the nucleus and drive expression of antioxidant enzymes HO-1 and NQO1. siRNA knockdown of Nrf2 abolished resveratrol's protective effects, confirming pathway dependence. Keap1 knockdown phenocopied resveratrol treatment, further validating the axis. In the mouse model, resveratrol partially restored pulmonary function parameters (including tidal volume, peak expiratory flow, and enhanced pause) and improved bronchoalveolar lavage fluid redox markers compared to CS-only animals.

These findings establish a coherent mechanistic chain: resveratrol → miR-200a upregulation → Keap1 suppression → Nrf2 activation → antioxidant enzyme induction → reduced ROS → TXNIP/NLRP3 inflammasome inhibition → decreased pyroptosis and IL-1β release. The miR-200a/Keap1/Nrf2 axis represents a previously underexplored regulatory node in COPD pathobiology, and this study is among the first to link miR-200a specifically to CS-induced pyroptosis.

While promising, the study has notable limitations. The in vivo model uses whole-body plethysmography rather than invasive spirometry, limiting direct translation to human FEV1/FVC metrics. Resveratrol's poor oral bioavailability and rapid metabolism were not addressed, and intratracheal delivery in mice may not reflect clinically feasible administration routes. No human clinical data are presented, and the durability of miR-200a induction by resveratrol over chronic exposure remains untested.