Genetic and pharmacological targeting of HINT2 promotes OXPHOS to alleviate inflammatory responses and cell necrosis in acute pancreatitis

Abstract

The necrosis of pancreatic acinar cells is a key molecular event in the progression of acute pancreatitis (AP), with disturbances in mitochondrial energy metabolism considered to be a direct causative factor of acinar cell necrosis. Histidine triad nucleotide-binding protein 2 (HINT2) has been implicated in the development of various diseases, whereas its involvement in the progression of AP remains unclear. This study aims to investigate the role of HINT2 in AP. HINT2 expression in pancreatic tissues was significantly downregulated after AP. The results of glutathione-S-transferase (GST) pull-down and proteomics analyses revealed the involvement of HINT2 in regulating mitochondrial oxidative phosphorylation (OXPHOS) in AP mice. Moreover, lentivirus-mediated HINT2 overexpression not only alleviated AP-induced ATP depletion, but also relieved inflammatory responses and cell necrosis. Mechanistically, HINT2 interacted with cytochrome C oxidase II (MTCO2) to promote mitochondrial OXPHOS, thereby reducing ROS accumulation and inhibiting the activation of inflammatory signaling pathway. Besides, HINT2 act as a direct pharmacological target of Emo to elicit protective effects on AP. Importantly, Emo upregulates the expression of HINT2 and OXPHOS complex proteins and enhances the interaction between HINT2 and MTCO2. Furthermore, CRISPR/Cas9-mediated HINT2 knockout significantly impaired the protective effects of Emo against AP-induced mitochondrial energy metabolism disorders, inflammatory responses, and acinar cell necrosis. Overall, these results uncover a previously unexplored role for HINT2 in maintaining mitochondrial energy metabolism in pancreatic acinar cells and reveals novel mechanism and target for Emo-mediated AP remission.