| Popis: |
Background: Oxidative stress is an imbalance between the production of reactive oxygen species (ROS) and the detoxification ability of reactive intermediates. It will lead to mitochondrial damage and dysfunction, resulting in the dysfunction of bioenergetic control and loss of ATP production, which is contributed to the pathogenesis of cardiac diseases. Dipeptidyl peptidase-4 (DPP4) is a transmembrane glycoprotein ubiquitously expressed and has multifunctional properties. DPP4 inhibitors are a class of oral diabetes drugs that inhibit the enzyme activity. In addition to its enzymatic property, considerably less is known regarding the nonenzymatic function of DPP4.Methods: We knocked down DPP4 gene expression in cultured cardiomyocytes to exclude any external and enzymatic substrate effects and compared the response between DPP4 knockdown and wild-type cardiomyocytes in response to oxidative stress.Results: H2O2-induced oxidative stress-stimulated intracellular and mitochondrial ROS concentration led to the loss of mitochondrial function, ATP production, and increased Bax and cleaved PARP expression, resulting in the loss of cell viability in cardiomyocytes. Oxidative stress induced DPP4 expression. Knocking down DPP4 ameliorated H2O2-induced loss of cell viability by preserving mitochondrial bioenergy, reducing intracellular ROS production, alleviating apoptosis-associated protein expression. Knocking down DPP4 increased its capability against oxidative stress by enhancing Nrf2 and PGC-1α signaling, which is associated with preserving mitochondrial function.Conclusions: DPP4 is a mediator of oxidative stress. Knocking down DPP4 without any external substrate mediators increased the capability of cardiomyocytes against oxidative stress, which indicated that DPP4 mediated more than the enzymatic-dependent pathway. |
