The Mitochondrial-Derived Peptide MOTS-c Attenuates Oxidative Stress Injury and the Inflammatory Response of H9c2 Cells Through the Nrf2/ARE and NF-κB Pathways

Oxidative stress and the inflammatory response contribute to the progression of cardiovascular disease. The present study aimed to investigate whether the mitochondrial-derived peptide MOTS-c could alleviate H2O2-induced oxidative stress and inflammatory status in H9c2 cells through activation of nuclear factor erythroid 2-related Factor 2 (Nrf2)/antioxidative response element (ARE) and inhibition of the NF-κB pathway. Rat H9c2 cardiomyocytes were obtained, and 10, 20 or 50 μM MOTS-c was pretreated for 24 h before treatment with H2O2. Then, the cell was treated with 100 μM H2O2 for 1 h to induce oxidative stress. An inhibition model of sh-Nrf2 was constructed via a lentivirus expression system, and an activation model of NF-κB was achieved using phorbol 12-myristate-13-acetate (PMA). Cell viability was determined using a Cell Counting kit-8 assay. Relative measurement of relative protein and mRNA expression used western blotting and qRT-PCR, respectively. Intracellular reactive oxygen species (ROS) levels were detected using dichlorodihydrofluorescein diacetate, and malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined via commercial kits. The protein expression and distribution in the cells were visualized by immunofluorescence analysis. Enzyme-linked immunosorbent assay was used to detect the levels of inflammatory cytokines, including TNF-α, IL-6 and IL-1β. We found that H2O2 treatment significantly decreased cell viability and the level of SOD, increased the levels of ROS and MDA, and upregulated the expression of inflammatory cytokines, including TNF-α, IL-6 and IL-1β, in H9c2 cells. The expression levels of Nrf2, HO-1 and NQO-1 were significantly downregulated in the H2O2, while the phosphorylation of NF-κBp65 was promoted by H2O2. However, pretreatment with MOTS-c significantly reversed H2O2-induced damage in H9c2 cells. Moreover, both inhibition of the Nrf2/ARE pathway and activation of the NF-κB pathway significantly decreased the effects of MOTS-c, suggesting that MOTS-c might play a role in alleviating oxidative damage via the Nrf2/ARE and NF-κB pathways. Our investigation indicated that MOTS-c could protect against H2O2-induced inflammation and oxidative stress in H9c2 cells by inhibiting NF-κB and activating the Nrf2/ARE pathways.