Exosomes Derived from Senescent Endothelial Cells Contain Distinct Pro‑angiogenic miRNAs and Proteins

Exosomes from senescence cells play pivotal roles in endothelium dysfunction. We investigated the exosomal angiogenic
cargo of endothelial cells (ECs) in a model of senescence in vitro. After inducing aging by H 2 O 2 , the expression of P53,
P21, and P16 was investigated by western blotting, while the expression of FMR1, miR-21, and miR-126 were measured by
real-time PCR (q-PCR). Oil Red O dye was used to stain cells. Acetylcholinesterase (AChE) assay, transmission electron
microscopy (TEM), and western blotting characterized Exosomes. Exosomal miR-21, miR-126, matrix metallopeptidase-9
(MMP-9), and tumor necrosis factor- ɑ (TNF-ɑ) proteins were measured by Q-PCR and western blotting. A wound-healing
assay was used to explore the effect of exosomes on ECs migration rate. The results showed that the expression of P53, P21,
P16, FMR1, and miR-21 was increased in treated cells as compared with control cells (P < 0.05). In addition, the expression
of miR-126 was decreased in treated cells (P < 0.05). The number of Oil Red O-positive-treated cells increased (P < 0.05).
The AChE activity of exosomes from treated cells was increased (P < 0.05). In comparison with control cells, an increase
in the expression levels of exosomal miR-21 and TNF-ɑ of treated cells coincided with a decrease in the expression levels
of miR-126 and MMP-9 levels (P < 0.05). We found that the migration rate of ECs co-cultured with exosomes from treated
cells was decreased (P < 0.05). The data indicate ECs under H 2 O 2 condition produce exosomes with distinct cargo that may
be useful as a biomarker of age-related vascular disease