Teneligliptin enhances the beneficial effects of GLP-1 in endothelial cells exposed to hyperglycemic conditions

High-glucose-induced oxidative stress contributes to cardiovascular endothelial damage in diabetes. Glucagon-like peptide 1 (GLP-1) is beneficial to endothelial cells, but its effects are diminished when cells are continuously exposed to high glucose. Teneligliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that prevents oxidative stress, apoptosis and the metabolic memory effect. We explored the potential additive effects of Teneligliptin and GLP-1 in hyperglycemia-damaged endothelial cells. Human umbilical vein endothelial cells (HUVECs) were exposed to normal-glucose (5 mmol/L) or high-glucose (HG, 25 mmol/L) for 21 days, or to HG for 14 days followed by normal-glucose for 7 days (HM). These cells were continually treated with Teneligliptin 3.0 μmol/L, alone or in combination with an acute dose of GLP-1 50 nmol/L. DPP-4 was upregulated under hyperglycemic conditions, but Teneligliptin reduced DPP-4 expression and activity. Simultaneous Teneligliptin and GLP-1 synergistically increased the antioxidant response and reduced ROS levels in HG- and HM-exposed HUVECs. Concurrent treatment also enhanced cell proliferation, reduced apoptotic gene expression and ameliorated endoplasmic reticulum stress in HG- and HM-exposed HUVECs. Thus, long-term Teneligliptin treatment reduced DPP-4 levels and activity in HUVECs exposed to chronic hyperglycemia. Moreover, Teneligliptin enhanced the beneficial effects of GLP-1 on oxidative stress, proliferation, apoptosis and endoplasmic reticulum homeostasis.