This study was aimed to explore the immunoregulatory function and capability supporting the
angiogenesis of
exosomes secreted by
bone marrow mesenchymal stem cells (BMMSC) from healthy
persons. Supernatant of BMMSC (P4-P6) was collected for exosome purification.
Transmission electron microscopy (TEM) and
Western blot were used to identify the quality of isolated
exosomes. The amount of
exosomes was quantified through bicinchoninic
acid (BCA)
protein assay.
Human peripheral blood mononuclear cells (PBMNC) were isolated from healthy
donor and added with isolating
exosomes. After co-cultured for 72 h, IFN-γ from the
co-culture system was detected by
ELISA. The expression of
miRNA-associated with
immunity were detected by real-
time reverse transcription polymerase chain reaction (Real-
time RT-PCR). The interactions between
exosomes and
human umbilical vein endothelial cells (HUVEC) were observed with
confocal microscopy. Subconfluent HUVEC were harvested and treated with the indicated concentration of
exosomes.
Nude mice were injected subcutaneously with
exosomes or PBS as control to verify the
ability of
angiogenesis. The results showed that diameter range of
exosomes was range from 40 to 160 nm. The isolated
exosomes expressed the CD9. There was approximately linear relation between the
secretion of
exosomes and
cell density. The
exosomes suppressed the
production of IFN-γ from PBMNC, and contained
miRNA associated with immune
regulation such as miR301, miR22 and miR-
let-7a.
Exosomes induced vascular tube formation
in vitro and vascularization of Matrigel plugs in vivo. It is concluded that the BMMSC-derived
exosomes can regulate
immunity and support vascularization.