Fig. 2
Characteristics of EVs derived from iPSCs cultured under different oxygen conditions: normoxia — 21% O2 (EV-N), hypoxia 5% O2 (EV-H5), and hypoxia 3% O2 (EV-H3). EVs from human dermal fibroblasts (DF-EVs) were used as control. A Images of EVs by transmission electron microscopy. B Representative histograms of EV size and concentration measured with the NanoSight device. C Size analysis of EVs by NanoSight (n = 4 for DF-EVs; n = 6 for hiPS-EVs). D Analysis of EV particle number per ml of conditioned medium (CM) (n = 4–6). E Analysis of the EV protein yield calculated per ml of CM (n = 4–6). F Ratio of EV particle number to protein concentration (n = 4–6). G Western blot analysis of proteins typical for EVs: syntenin, flotillin1, CD9, CD81, a protein present in the cell culture medium (transferrin), pluripotency markers (OCT4, CD133, E-cadherin), endoplasmic reticulum protein (calnexin; a negative marker), and control — β-tubulin. H Densitometric analysis of CD81 protein level in EV preps derived from different oxygen conditions (n = 3). I Confocal microscopy images of DiD-labeled EVs (red) uptake by human cardiac fibroblasts (hCF; stained in green with DiO). Representative images of different cell depths are shown. All data are presented as the mean ± SD. Statistical significance was tested using Welch ANOVA and the Dunnett post hoc test (C–E) and with the one-way ANOVA and the Tukey post hoc test (F, H). *p < 0.05, **p < 0.01