Journal de recherche et de thérapie sur les cellules souches

Abstrait

The Angiogenic Potential of Adipose Mesenchymal Stem Cell-derived Extracellular Vesicles is modulated by Basic Fibroblast Growth Factor

Tatiana Lopatina, Aurora Mazzeo, Stefania Bruno, Ciro Tetta, Natalia Kalinina, Renato Romagnoli, Mauro Salizzoni, Massimo Porta and Giovanni Camussi

Objective: The aim of the present study was to investigate the effects of basic fibroblast growth factor (bFGF) on the angiogenic properties of extracellular vesicles (EVs) secreted by adipose-derived mesenchymal stem cells (ASCs) in culture.
Methods: We isolated EVs from ASC (ASC-EVs) cultured with bFGF (FGF-EVs) or without bFGF (b-EVs). We compared the EV angiogenic action on human microvascular endothelial cells (HMEC) in vitro by capillarylike structure formation assay and in vivo by subcutaneous injection of HMEC-containing Matrigel in SCID mice. We analysed micro-RNA composition of EVs by PCR array and we selected two mi-RNAs changed after bFGF stimulation: miR-223 and miR-21. We transfected HMEC with short antisense anti-miR-223 or with mimic miR- 21 to compensate the action of EVs.
Results: In vitro, the total length and the number of branches of vessel-like structures formed by FGF-EVstimulated HMEC were significantly reduced in respect to b-EV stimulation and the structures were significantly larger than after b-EV stimulation. In vivo, vessels formed by FGF-EV-stimulated HMEC were significantly lower in number in respect to those formed by b-EV-stimulated HMEC, but they were significantly larger in size and contained cells positive for mouse smooth muscle actin. We found that bFGF led to molecular changes in ASCEVs characterized by decreased expression of angiogenic factors. Moreover, bFGF stimulation up-regulated the expression of the anti-angiogenic miR-223 and decreased the level of pro-angiogenic miR-21. The effects of FGFEVs were antagonized by the inhibition of miR-233 and by the miR-21 mimic
Conclusions: The results indicate that culture conditions may modify the pro-angiogenic activity of ASCderived EVs, changing their protein and RNA contents. In particular, bFGF induces production of EVs that stimulate vessel stabilization rather than an increase in vessel number.