Isolation, characterization and potential role in beta cell-endothelium cross-talk of extracellular vesicles released from human pancreatic islets

PLoS One. 2014 Jul 16;9(7):e102521. doi: 10.1371/journal.pone.0102521. eCollection 2014.

Abstract

The cross-talk between beta cells and endothelium plays a key role in islet physiopathology and in the revascularization process after islet transplantation. However, the molecular mechanisms involved in this cross-talk are not fully elucidated. Extracellular vesicles (EVs) are secreted membrane nanoparticles involved in inter-cellular communication through the transfer of proteins and nucleic acids. The aims of this study were: 1) isolation and characterization of EVs from human islets; 2) evaluation of the pro-angiogenic effect of islet-derived EVs on human islet endothelial cells (IECs). EVs were isolated by ultracentrifugation from conditioned medium of human islets and characterized by nanotrack analysis (Nanosight), FACS, western blot, bioanalyzer, mRNA/microRNA RT-PCR array. On IECs, we evaluated EV-induced insulin mRNA transfer, proliferation, resistance to apoptosis, in vitro angiogenesis, migration, gene and protein profiling. EVs sized 236±54 nm, expressed different surface molecules and islet-specific proteins (insulin, C-peptide, GLP1R) and carried several mRNAs (VEGFa, eNOS) and microRNAs (miR-27b, miR-126, miR-130 and miR-296) involved in beta cell function, insulin secretion and angiogenesis. Purified EVs were internalized into IECs inducing insulin mRNA expression, protection from apoptosis and enhancement of angiogenesis. Human islets release biologically active EVs able to shuttle specific mRNAs and microRNAs (miRNAs) into target endothelial cells. These results suggest a putative role for islet-derived EVs in beta cell-endothelium cross-talk and in the neoangiogenesis process which is critical for engraftment of transplanted islets.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inducing Agents / metabolism*
  • Blotting, Western
  • Cell Communication / physiology*
  • Endothelial Cells / cytology
  • Endothelial Cells / physiology*
  • Flow Cytometry
  • Humans
  • Insulin-Secreting Cells / physiology*
  • MicroRNAs / metabolism
  • RNA, Messenger / metabolism
  • Receptor Cross-Talk / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transport Vesicles / metabolism*

Substances

  • Angiogenesis Inducing Agents
  • MicroRNAs
  • RNA, Messenger

Grants and funding

This work was supported by Regione Piemonte, Piattaforme Biotecnologiche PiSTEM project (GC) and Local University Grants (VC, LB and GC). The sponsors did not contribute to the design, data collection and analysis, decision to publish, and preparation of the manuscript.