Abstract 11725: Exosomes Secreted from TSG6-Rich Adipose-Derived Stem Cells Induce Neovascularization in Ischemic Limb

Abstract

Introduction: Therapeutic angiogenesis is attractive for tackling cardiovascular disease. Exosomes, which contain growth factors and micro RNAs, might be useful to develop cell-free therapeutic angiogenesis. Previously we have reported that CD271+ADRCs have excellent angiogenic activity. In this study, we investigated the in vivo angiogenic effects and mechanisms of CD271+ ADSC-derived exosomes (CD271+ Exo) using a mouse model of limb ischemia. Methods: We analyzed single-cell RNA-sequencing data of human stromal vascular fraction (SVF) cells. After normalization and clustering, CD271+ and CD271- cells were analyzed in DESeq2. Next, we established CD271+/- ADSCs from human SVF using FACS. After 48 hours of serum deprivation, conditioned media was collected. Exosomes were purified by magnetic isolation using phosphatidylserine/Tim4 interaction and confirmed by ELISA of exosomal markers. We labeled exosomes by PKH26 membrane dye and injected them into a mice model of limb ischemia. After 2 weeks, lectin perfused limb was harvested and analyzed by immunohistochemistry (Fig.A). Results: In single-cell transcriptome of human SVF, TSG6 was predominantly expressed in Lineage-CD34+ stromal cells. Furthermore, TSG6 was significantly upregulated in CD271+ SVF cells compared to CD271- SVF cells and other cluster cells (Fig.B). Consistently, TSG6 mRNA expression was upregulated in CD271+ ADSCs (Fig.C). We confirmed exosomal marker expression (CD63, CD9, and CD81) of isolated Exo (Fig.D). In exosome therapy, CD271+ Exo promotes neovascularization compared to CD271- Exo or PBS. Notably, there were more cells containing PKH labeling in the CD271+ Exo-treated group (Fig.E). Conclusions: This study reveals a novel mechanism by which CD271+ Exo promotes angiogenesis via TSG6. CD271+ Exo would be useful for cell-free therapeutic angiogenesis.