Activation of AMPK/mTOR-driven autophagy and inhibition of NLRP3 inflammasome by saxagliptin ameliorate ethanol-induced gastric mucosal damage

Abstract

AimsSaxagliptin, a selective/potent dipeptidyl peptidase-4 inhibitor, has revealed remarkable anti-inflammatory features in murine models of nephrotoxicity, hepatic injury, and neuroinflammation. However, its potential effect on ethanol-induced gastric mucosal injury has not been examined. Hence, the present work investigated the prospect of saxagliptin to attenuate ethanol-evoked gastric injury, with emphasis on the AMPK/mTOR-driven autophagy and NLRP3/ASC/caspase-1 pathway. Materials and methodsIn ethanol-induced gastropathy, the gastric tissues were examined by immunohistochemistry, immunoblotting, histopathology, and ELISA. Key findingsThe results demonstrated that saxagliptin (10 mg/kg; by gavage) suppressed the gastric pathological signs (area of gastric ulcer and ulcer index scores), histopathologic aberrations/damage scores, without provoking hypoglycemia in rats. These protective features were attributed to the enhancement of gastric mucosal autophagy flux, as proven with increased expression of LC3-II and Beclin 1, decreased accumulation of p62 SQSTM1, and activation of the autophagy-linked AMPK/mTOR pathway by increasing the expression of p-AMPK/AMPK and decreasing the expression of the autophagy suppressor p-mTOR/mTOR signal. In tandem, saxagliptin counteracted the ethanol-induced pro-apoptotic events by downregulating Bax, upregulating Bcl2 protein, and lowering the Bax/Bcl2 ratio. Equally important, saxagliptin suppressed the NLRP3 inflammasome in the gastric tissue by lowering the expression of NLRP3, ASC, and nuclear NF-κBp65, decreasing the activity of caspase-1, and diminishing the IL-1β levels. In the same regard, saxagliptin suppressed the mucosal oxidative stress by lowering lipid peroxide levels, increasing GSH and GPx antioxidants, and activating Nrf2/HO-1 pathway. SignificanceSaxagliptin may be a promising intervention against ethanol-evoked gastropathy by activating AMPK/mTOR-driven autophagy and inhibiting NLRP3 inflammasome.