Abstract: TH-PO333

Urinary Extracellular Vesicles in Tubular Cell Repair

Session Information

Category: Acute Kidney Injury

  • 002 AKI: Repair and Regeneration

Authors

  • Bussolati, Benedetta, University of Torino , Torino, Italy
  • Dimuccio, Veronica, Univerity of Turin, Turin, Italy
  • Grange, Cristina, University of Turin, Turin, Italy
  • Papadimitriou, Elli, University of Turin Italy, Turin, Italy
Background

Extracellular vesicles (EVs) are emerging as an integral component of the cell-to-cell communication network. EVs may actively transfer to target cells various molecules including proteins, mRNAs and microRNA, with stable epigenetic changes. Urinary EVs in particular, released by cells lining the nephron, are abundantly present in urine and may be involved in intra-nephron communication among cells. We here evaluate the possible role of urinary EVs in repair of renal tissue after AKI.

Methods

EVs were isolated by urine of normal subjects by ultracentrifugation and gradient sedimentation. CD133+ and CD133neg EVs were separated by magnetic sorting. EV populations were subjected to nanoparticle tracking analysis to define their dimension and profile and measure EV mean, distribution and concentration. EVs were characterized by marker expression using Western Blot and FACS analysis. MicroRNA content was assessed by qRT-PCR using a MicroRNA Assay Human Panel Early Access kit to profile 754 human mature miRNAs. EVs from mesenchymal stem cells were used as control. Urinary EVs were injected in mice undergoing AKI (day 1) by intramuscle injection of glycerol.

Results

CD133+ and CD133neg vesicles obtained from urine showed similar expression of exosomal markers. CD133+ and CD133neg EVs showed selective expression of a panel of microRNAs. Functional Enrichment analysis tool showed enrichment in pathways related to matrix-receptor interaction, adhesion as well as pathways regulating pluripotency in CD133+ EVs, where pathways involved in TGF-beta signalling, cell cycle and mTor signalling in CD133 negative EVs. EV administration to AKI mice showed a selective improvement of renal function and histology. In particular, CD133neg EVs promoted repair in a comparable level to MSC-EVs. CD133+ EVs did not show repairing effect. This was confirmed by administration of CD133+ EVs isolated by CD133+ cells in culture. Bioimaging of injected CD133neg EVs showed their rapid localization and internalization within tubules in AKI mice.

Conclusion

These data indicate that EVs within urine may support repair of tubular cells, indicating a possible paracrine action of EVs released within urine to damaged cells in lower tubular compartments. This was not obtained by CD133+ EVs suggesting selective effects of cells within tubules in its repair.

Funding

  • Government Support - Non-U.S.