Abstract 177: Exosomal Micrornas From Ischemic Cerebral Endothelial Cells and Neural Stem Cells Regulate Coupling of Neurogenesis and Angiogenesis

• Published in: Stroke (1970) Vol. 49; no. Suppl_1
• Main Authors: Liu, Xianshuang, Pan, Wanlong, Li, Chao, Zhang, Ruilan, Fan, Baoyan, Wang, Xinli, Zhang, Xiaoming, Hu, Jia Ni, Chopp, Michael, Zhang, Zheng Gang
• Format: Journal Article
• Language: English
• Published: 22.01.2018
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/str.49.suppl_1.177

Abstract only Introduction: Molecular mechanisms underlying coupling of angiogenesis and neurogenesis remain unknown. We tested the hypothesis that exosomes mediate coupling of stroke-induced angiogenesis and neurogenesis by transferring exosomal cargo miRNAs between ischemic cerebral endothelial cells (CECs) and neural stem cells (NSCs). Methods and Results: Cell-type specific e xosomes were purified from conditional media of cultured CECs and NSCs harvested from non-ischemic and ischemic rats, respectively. Exosome markers and size distribution were verified with Western blot and transmission electron microscopy, respectively. Using an advanced Cre-Loxp system, we found CEC-exosomes carrying Cre recombinase were taken up by recipient NSCs to induce genome recombination. We then tested if exosomal miRNAs mediated cell-to-cell interplay. First, using miRNA array, we identified that miR-146a and miR-125a were the most upregulated miRNAs in ischemic CECs-exosomes. Incubation of non-ischemic NSCs with ischemic CECs-exosomes substantially increased these two miRNA levels in recipient NSCs, which led to downregulation of their target genes, IRAK1, TRAF6 as well as BAK1 and KLF13, consequently leading to an increase in Tuj1 + and NG2 + cells (p<0.05). These data suggest that CEC-exosomes transfer miRNAs to NSCs and thereby promote neuronal differentiation. Moreover, stroke increased miR-106b and miR-125b in NSCs-exosomes. Incubation of non-ischemic CECs with ischemic NSC-exosomes elevated both miRNAs in CECs, which resulted in a significant increase in capillary tube formation, suggesting that ischemic NSC-exosomes promote angiogenesis. The effect of ischemic CEC-exosomes and ischemic NSC-exosomes on differentiation of NCSs and CECs, respectively, is specific, because ischemic CEC- and NSC-exosomes derived from cells with knockdown of Rab27, a protein that regulates miRNA sorting into exosomes, completely abolished elevation of listed miRNAs in recipient cells. Conclusion: Our data demonstrate that exosomes derived from ischemic CECs and NSCs mediate NSC and CEC function, respectively, by transferring their cargo miRNAs, suggesting that these exosomes can be used as a therapy for amplifying angiogenesis and neurogenesis in ischemic brain.