Flufenamic acid inhibits pyroptosis in ischemic flaps via the AMPK-TRPML1-Calcineurin signaling pathway

Background Ischemic injury is a primary cause of distal flap necrosis. Previous studies have shown that Flufenamic acid (FFA) can reduce inflammation, decrease oxidative stress (OS), and promote angiogenesis, suggesting its potential role in protecting flaps from ischemic damage. This study investigated the effects and mechanisms of FFA in enhancing the survival of ischemic flaps. Methods The viability of ischemic flaps was evaluated using laser doppler blood flow (LDBF) and survival rates. We examined levels of pyroptosis, OS, transcription factor E3 (TFE3)-induced autophagy, and elements of the AMPK-TRPML1-Calcineurin pathway through western blotting (WB), immunofluorescence (IF), molecular docking (MD), cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR). Results The findings suggest that FFA significantly enhances the viability of ischemic flaps. The improvement in flap survival associated with FFA can be attributed to increased autophagy, diminished OS, and the suppression of pyroptosis. Notably, the promotion of autophagy flux and an augmented resistance to OS are instrumental in curbing pyroptosis in these flaps. Activation of TFE3 by FFA promoted autophagy and diminished oxidative damage. The therapeutic effects of FFA were negated when TFE3 levels were decreased using adeno-associated virus (AAV)-TFE3shRNA. Additionally, FFA modified TFE3 activity through the AMPK-TRPML1-Calcineurin pathway. Conclusions FFA promotes ischemic flap survival via induction of autophagy and suppression of oxidative stress by activation of the AMPK-TRPML1-Calcineurin-TFE3 signaling pathway. These findings could have therapeutic implications.