Modulation of AMPK/NLRP3 Signaling Mitigates Radiation-Induced Lung Inflammation by a Synthetic Lipoxin A4 Analogue

Radiation-induced lung inflammation (RILI) is a major complication of thoracic radiotherapy, characterized by excessive inflammation and subsequent fibrosis that compromise pulmonary function and treatment outcomes. This study explores the pharmacological properties of a newly synthesized Lipoxin A4 analogue (CYNC-2) to mitigate RILI by modulating the AMP-activated protein kinase (AMPK)/NOD-like receptor family pyrin domain containing 3(NLRP3) inflammasome pathway. A murine RILI model was established in mice by delivering a single high-dose (ablative) X-ray irradiation to the left lung. Mice in the treatment group received CYNC-2 via tail-vein injection three times per week for 2 weeks. The effects of CYNC-2 on RILI were evaluated histological, immunohistochemical analysis of lung tissues, cytokine profiling, lung function testing using a FlexiVent system, and micro-computed tomography (micro-CT) imaging of lung damage. In parallel, two human lung cell lines-L132 (normal bronchial epithelial cells) and A549 (lung carcinoma cells)-were irradiated with 6 Gy X-rays and treated with CYNC-2 to assess cell viability and changes in AMPK/NLRP3 pathway markers via qPCR and immunofluorescence. Lung tissue sample from patients who underwent thoracic radiotherapy were also examined to validate key findings. CYNC-2 activated AMPK and inhibited mTOR signaling, which suppressed NLRP3 inflammasome activation and led to reduced secretion of pro-inflammatory cytokines (IL-1β, IL-6, and TGF-β1). In vitro, CYNC-2 mitigated radiation-induced inflammatory responses and preserved cellular viability. Overall, CYNC-2 effectively dampened acute pulmonary in the RILI model. These findings suggest that targeting the AMPK/NLRP3 inflammasome pathway via a stable LXA4 analogue such as CYNC-2 is a promising therapeutic strategy to improve clinical outcomes for patients receiving thoracic radiation therapy.