Melatonin pretreatment of human adipose tissue-derived mesenchymal stromal cells enhances their prosurvival and protective effects on human kidney cells

The efficacy of cell therapy for many diseases can be limited by the poor survival of implanted cells in an environment of tissue injury. Melatonin has been reported to have antioxidative and antiapoptotic effects. Adipose tissue-derived mesenchymal stromal cells (ASCs), cells easily obtained in high amounts and with minimal discomfort, have shown great promise in cell therapy applications, such as in acute kidney injury. We hypothesized that melatonin pretreatment of human ASCs (hASCs) would improve their renoprotective and prosurvival effects. We therefore investigated the action of melatonin on hASCs, as well as the effect of the resulting hASCs-conditioned media (CM) on human kidney cells exposed to oxidative and apoptotic injury-provoking doses of cisplatin. Our results demonstrated that pretreatment of hASCs with melatonin, 100 mu M for 3 h, significantly increased their proliferation and their expression of prosurvival P-Erk1/2 and P-Akt, and of antioxidative enzymes catalase and heme oxygenase (HO)-1. In addition, the CM from hASCs pretreated with melatonin provoked a significantly higher proliferation and migration of HK-2 human kidney epithelial cells. Furthermore, this CM exerted significantly higher prosurvival and antiapoptotic actions on HK-2 cells exposed to cisplatin in vitro. Western blot analysis showed higher expression of P-Erk1/2, Bcl-2, SOD-1, and HO-1 in the HK-2 cells exposed to cisplatin in the presence of CM from melatonin-pretreated hASCs. In sum, our study revealed that in vitro pretreatment of hASCs with melatonin may significantly enhance their survival and their therapeutic effectiveness on injured tissue.