Exosomes from adipose mesenchymal stem cells overexpressing Stanniocalcin-1 promote reendothelialization after carotid endarterium mechanical injury

Stanniocalcin-1 (STC-1) is a secreted glycoprotein that participates in the regulation of inflammation, apoptosis, and necrosis. We investigated the reendothelialization effect of exosomes from adipose stem cells (ADSC) overexpressing STC-1 on injured carotid endarterium. ADSCs were transfected with lentivirus vectors containing pre-STC-1. PHK-26 as molecular probe was used to track the exosomes engulfed by mice arterial endothelial cells (MAEC). The role of STC-1-ADSC-Exosome (S-ADSC-Exo) in MAECs was verified through scratch test and tube forming. Expressions of STC-1 and NLRP3 inflammasome were detected by western blot and quantitative reverse transcription polymerase chain reaction. Reendothelialization effect was inhibited by the antagonist of siRNA targeting STC-1. Carotid endarterium mechanical injury was induced by insertion with a guidewire into the common carotid artery lumen. Carotid arteries were harvested for histological examination, immunofluorescence staining, and Evan’s blue staining. Transfection of STC-1 significantly enhanced STC-1 levels in ADSCs, their exosomes, and MAECs. Compared with the control group and the ADSC-Exo group, STC-1 enriched exosomes markedly inhibited the expressions of NLRP3, Caspase-1, and IL-1β in MAECs, exhibited good lateral migration capacity, and promoted angiogenesis. Administration of siRNA targeting STC-1 completely abolished down-regulation of NLRP3, Caspase-1, and IL-1β by STC-1 and inhibited effects of S-ADSC-Exo on lateral migration and angiogenesis. In vivo administration of S-ADSC-Exo had reendothelialization effect on post-injury carotid endarterium as evidenced by thinner arterial wall, low-expressed NLRP3 inflammasome, and more living endothelial cells. The reendothelialization effect of exosomes from ADSCs on post-injury carotid endarterium could be enhanced by genetic modification of the exosomes to contain elevated STC-1, possibly through suppression of NLRP3 inflammasome-mediated inflammation.