CLDN4 promotes ferroptosis and inflammation involving JAK2/STAT3 pathway in acute pancreatitis.

Acute pancreatitis (AP) is a severe inflammatory disease characterized by pancreatic acinar cell injury and oxidative stress. Ferroptosis, an iron-dependent form of cell death driven by lipid peroxidation, has been implicated in AP pathogenesis. However, the molecular mechanisms linking ferroptosis to AP remain unclear. Using a cerulein-induced AP mouse model and cerulein-stimulated 266-6 pancreatic acinar cells, we performed RNA sequencing to identify differentially expressed genes (DEGs). Claudin-4 (CLDN4) was selected for further investigation. We evaluated the effects of CLDN4 knockdown on cell viability, apoptosis, inflammatory cytokine production, ferroptosis markers, and janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway utilizing quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blot, enzyme-linked immunosorbent assays (ELISA), immunofluorescence, flow cytometry, and histopathological analyses, respectively. We found that CLDN4 expression was significantly upregulated in AP pancreatic tissues and cells. CLDN4 knockdown enhanced cell viability, reduced apoptosis, and decreased reactive oxygen species (ROS), iron accumulation, and inflammatory cytokines (TNF-α, IL-6, IL-17). It also restored glutathione peroxidase 4 (GPX4) levels and reduced acyl-CoA synthetase long-chain family member 4 (ACSL4) expression, indicating suppression of ferroptosis. In vivo, CLDN4 knockdown ameliorated pancreatic injury and oxidative stress. Mechanistically, CLDN4 knockdown correlated with decreased activation of the JAK2/STAT3 pathway, and combined inhibition with AG490 provided additive protective effects. Our study identifies CLDN4 as a novel regulator of ferroptosis and inflammation in AP that may be linked to the JAK2/STAT3 pathway. Targeting CLDN4 may offer a promising therapeutic strategy for mitigating pancreatic injury in acute pancreatitis.