Biogenerated oxygen-related environmental stressed apoptotic body targets endothelial cells

he dynamic balance of hypoxia and oxidative stress constitutes the oxygen-related microenvironment in injured tissues. Oxygen homeostasis is highly variable; therefore, it is not a therapeutic target for injured tissue repair. We found an enrichment and extensive apoptosis of mesenchymal stem cells (MSCs) infused intravenously in the wound microenvironment with co-existing hypoxia and oxidative stress. Apoptotic bodies (ABs), generated from in situ apoptosis, significantly promotes angiogenesis. We improved the derivation pathway of ABs by simulating oxygen homeostasis in injured tissues, with cobalt chloride-induced hypoxia or hydrogen peroxide-induced oxidative stress in MSCs. Oxygen-related environmental stressed ABs, derived from environments of hypoxic and oxidative stress, were identified and loaded onto hydrogel microspheres for accurate regulation of endothelial cells (ECs) vascularization. These ABs directly targeted ECs; oxidative stress ABs (Oxi-ABs) have a 2.5- and 4-fold higher tube-forming ability than hypoxic and normoxic ABs, respectively. miRNA microarray analysis revealed that different oxygen-stressed ABs deliver similar miRNAs, which leads to the broad upregulation of EC phosphokinase activity. Finally, local delivery of Oxi-ABs-loaded hydrogel microspheres promotes wound healing. Oxi-ABs-loaded hydrogel microspheres achieved controlled AB release, targeting EC by reducing the consumption of early inflammatory cells and adapting to the proliferative phase of wound healing. Thus, the biogenerated apoptotic bodies responding to oxygen-related environmental stress can target ECs to promote vascularization. After co-culturing with PBS or 100 μM CoCl2 or 50 μM H2O2 for 24 h, MSC were induced to apoptosis and miRNA expression was measured in the harvested apoptotic vesicles. Three independent experiments were performed for each individual culture condition, using a different batch of cells for each experiment.