In this study, researchers from Johns Hopkins University School of Medicine examined properties and functions of EVs from human induced pluripotent stem cells (iPSCs) that can be cultured infinitely under a chemically defined medium free of any exogenous EVs. The researchers collected and purified EVs secreted by human iPSCs and MSCs. Purified EVs produced by both stem cell types have similar sizes (~150 nm in diameter), but human iPSCs produced 16-fold more EVs than MSCs. When highly purified iPSC-EVs were applied in culture to senescent MSCs that have elevated reactive oxygen species (ROS), they reduced cellular ROS levels and alleviated aging phenotypes of senescent MSCs. This discovery reveals that EVs from human stem cells can alleviate cellular aging in culture, at least in part by delivering intracellular peroxiredoxin antioxidant enzymes.
Uptake of W5 and effects on the growth of recipient cells
(A) Time—course analysis of uptake of PKH26 red fluorescent dye‐labelled iPSC‐EVs and MSC‐EVs by MSCs. Scale bar, 50 p.m. (b) Representative images of BC1—EV and BC1‐MSC—EV uptake by MSCS after PKH26 red fluorescent dye labeling. Scale bar, 50 μm. (C) Quantification of PKH26 staining on MSCs. (D) Quantification of DAPI staining in MSCS. (E) Measurements of labeling efficiency of iPSC‐Evs and MSC‐EVs by PKH26 red fluorescent dye. (F) AlamarBlue assay to assess the cell growth of early‐passage MSCs (p3‐p5) after incubation with iPSC‐EVs or MSC‐EVs. (G) AlamarBlue assay to assess the cell growth of early‐passage HUVECs (p4‐p7) after incubation with iPSC‐EVs or MSC‐EVs. All data reflect mean ± SD from 3 independent experiments. ns, not significant; **p < .01.