PEDF and PEDF-derived peptide 44mer inhibit oxygen–glucose deprivation-induced oxidative stress through upregulating PPARγ via PEDF-R in H9c2 cells

Pigment epithelial-derived factor (PEDF) is a glycoprotein with broad biological activities including inhibiting oxygen–glucose deprivation(OGD)-induced cardiomyocytes apoptosis through its anti-oxidative properties. PEDF derived peptide-44mer shows similar cytoprotective effect to PEDF. However, the molecular mechanisms mediating cardiomyocytes apoptosis have not been fully established. Here we found that PEDF and 44mer decreased the content of ROS. This content was abolished by either PEDF-R small interfering RNA (siRNA) or PPARγ antagonist. The level of Lysophosphatidic acid (LPA) and phospholipase A2 (PLA2) was observed as drawn from the ELISA assays. PEDF and 44mer sequentially induced PPARγ expression was observed both in qPCR and Western blot assays. The level of LPA and PLA2 and PPARγ expression increased by PEDF and 44mer was significantly attenuated by PEDF-R siRNA. However, PEDF and 44mer inhibited the H9c2 cells and cultured neonatal rat myocardial cells apoptosis rate. On the other hand, TUNEL assay and cleavage of procaspase-3 showed that PEDF-R siRNA or PPARγ antagonist increased the apoptosis again. We conclude that under OGD condition, PEDF and 44mer reduce H9c2 cells apoptosis and inhibit OGD-induced oxidative stress via its receptor PEDF-R and the PPARγ signaling pathway.