Knockdown of Nr4a3 mitigates acute pancreatitis-induced injury by modulating Btg2 to reduce oxidative stress, mitochondrial damage, and apoptosis

Acute pancreatitis (AP) has a high mortality, involving oxidative stress and mitochondrial damage. Nuclear receptor subfamily 4 group A member 3 (Nr4a3) and BTG anti-proliferation factor 2 (Btg2) have a close connection with mitochondrial damage. Here, we found that Nr4a3 expression was upregulated in pancreatic tissues of AP mice induced by cerulein. To elucidate Nr4a3's role, we injected adeno-associated virus 9 (AAV9) carrying Nr4a3-targeting short hairpin RNA into the pancreatic duct. This intervention reduced pancreatic edema, inflammatory infiltration, and acinar cell necrosis by suppressing pancreatic enzyme activation. Moreover, Nr4a3 knockdown improved mitochondrial function in pancreatic acinar cells, evidenced by increased mitochondrial membrane potential, enhanced ATP production, and decreased superoxide levels. It also inhibited cell apoptosis by suppressing the activation of the caspase pathway. In vitro, Nr4a3 knockdown in CCK-treated pancreatic acinar cells decreased oxidative stress, mitigated mitochondrial damage, and suppressed apoptosis, while Nr4a3 overexpression exacerbated cell injury. Further investigation identified Btg2 as a downstream target of Nr4a3. Btg2 expression was elevated in pancreatic acinar cells of AP mice, and siRNA-mediated Btg2 knockdown alleviated CCK-induced cell injury. Mechanistically, Nr4a3 promoted Btg2 transcription, thereby promoting mitochondrial damage in pancreatic acinar cells and leading to cell apoptosis. Btg2 overexpression reversed the protective effects of Nr4a3 knockdown. Overall, our findings demonstrate that downregulation of Nr4a3 exerts anti-AP effects by regulating Btg2, providing potential therapeutic targets for AP.