Betulinic Acid Alleviates Acute Pancreatitis by Promoting SIRT1-PINK1-Mediated Mitophagy in Acinar Cells

Betulinic acid (BA) has the potential to ameliorate acute pancreatitis (AP); however, the mechanisms have not been fully elucidated. This study aimed to identify the effect of BA on mitophagy and its mediated acetylation. Rat pancreatic acinar AR42J cells were treated with cerulein to simulate AP-induced injury, and then inflammation and mitophagy were evaluated after BA treatment. The molecular mechanisms were analyzed using molecular docking, immunoprecipitation, immunoblotting, and cycloheximide chase assay. The roles of BA and SIRT1 in vivo were assessed by HE staining and enzyme-linked immunosorbent assay. The results showed that BA inhibited inflammation and promoted mitophagy in cerulein-induced AR42J cells. BA combined with SIRT1 and reduced SIRT1-mediated acetylation. Knockdown of SIRT1 counteracted the inflammation and mitophagy caused by BA. Moreover, interference with SIRT1 promoted acetylation of PINK1 to degrade PINK1 protein, which knockdown reversed the inhibition of inflammation and the promotion of mitophagy induced by SIRT1. Additionally, BA inhibited pancreatic tissue injury and inflammation levels in the pancreas in AP mice by regulating SIRT1. In conclusion, BA decelerates the progression of AP by promoting mitophagy and inhibiting inflammation in pancreatic acinar cells. Mechanically, BA increased SIRT1 expression, which knockdown degraded PINK1 protein by inducing acetylation of PINK1.