Renal scattered tubular-like cells confer protective effects in the stenotic murine kidney mediated by release of extracellular vesicles

To test the hypothesis that intrinsic renal scattered tubular cells (STC-like cells) contribute to repairing injured tubular epithelial cells (TEC) by releasing extracellular vesicle (EV). EV released from primary cultured pig STC-like cells were confirmed by electron microscopy. Antimycin-A (AMA)-induced injured proximal TEC (PK1 cells) were co-cultured with STC-like cells, STC-like cells-derived EV, or EV-free conditioned-medium for 3 days. Cellular injury, oxidative stress and mitochondrial function were assessed. Transfer of mitochondria from STC-like cells to TEC was assessed using Mito-trackers, and their viability by mitochondrial membrane potential assays. STC-like cells-derived EV were intra-arterially injected into mice 2 weeks after induction of unilateral renal artery stenosis. Two weeks later, renal hemodynamics were studied using magnetic-resonance-imaging, and renal fibrosis assessed ex-vivo. Cultured STC-like cells released EV that were uptaken by TEC. A protective effect conferred by STC-like cells in AMA-induced TEC injury was partly mimicked by their EV. Furthermore, STC-like cells-EV carried and transferred mitochondrial material to injured TEC, which partly restored mitochondrial function. In vivo, STC-like cells-derived EV engrafted in the stenotic kidney, and improved its perfusion and oxygenation. STC-like cells-EV exert protective effects on injured tubular cells in vitro and in vivo, partly by transferring STC-like cells mitochondria, which remain at least partly functional in recipient TEC.