Oleuropein attenuates hydrogen peroxide-induced autophagic cell death in human adipose-derived stem cells

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with self-renewing properties; thus, transplanting functionally enhanced MSCs might be a promising strategy for cell therapy against ischemic diseases. However, extensive oxidative damage in ischemic tissue affects the cell fate of transplanted MSCs, eventually resulting in cell damage and autophagic cell death. Oleuropein (OLP) is a bioactive compound isolated from olives and olive oil that harbors antioxidant properties. This study aimed to investigate the potential cytoprotective effects of OLP against oxidative stress and autophagic cell death in MSCs. We found that short-term priming with OLP attenuated H2O2-induced apoptosis by regulating the pro-apoptotic marker Bax and the anti-apoptotic markers Bcl-2 and Mcl-1. Notably, OLP inhibits H2O2 -induced autophagic cell death by modulating autophagy-related death signals, including mTOR (mammalian target of rapamycin), ULK1 (unc-51 like autophagy activating kinase 1), Beclin-1, AMPK (AMP-activated protein kinase), and LC3 (microtubule-associated protein 1a/1b-light chain 3). Our data suggest that OLP might reduce H2O2-induced autophagy and cell apoptosis in MSCs by regulating both the AMPK-ULK axis and the Bcl-2-Mcl-1 axis. Consequently, short-term cell priming with OLP might enhance the therapeutic effect of MSCs against ischemic vascular diseases, which provides an important potential improvement for emerging therapeutic strategies.