LAUSR

BACKGROUND Endothelial progenitor cells (EPCs) play a pivotal role in endothelial repair following artery injury, however, the molecular mechanism of late outgrowth EPCs (LEPCs) in endothelial repair remained to be studied. Bone morphogenetic protein 4 (BMP4) is involved in vascular injury-mediated mobilization and homing of LEPCs. Here, we investigated the influence of BMP4-modified signaling pathway in LEPC-related endothelial repair of human and underlying molecular mechanism. METHODS AND RESULTS In vitro, after a 28day culture, human LEPCs were pretreated with different concentrations of recombinant BMP4 (0, 10, 50, or 100ng/mL), which markedly augmented the migration and adhesion in vitro and demonstrated a significantly accelerated in vivo endothelial repair capacity of human LEPCs after transplantation into nude mice with carotid artery denudation injury. Moreover, the main Id gene (Id2), a well-characterized down-streaming target of BMP4, upregulated in LEPCs incubated with recombinant BMP4. The BMP4-induced enhancement in in vitro functional activities and in vivo endothelial repair capacity of human LEPCs were abolished by pretreatment with BMP antagonist Noggin or shRNA-mediated knockdown of BMP4 expression. Furthermore, BMP4 gene transfer remarkably activated BMP4-mediated signaling pathway and facilitated therapeutic endothelial repair capacity of LEPCs, and the improved functional activities of human LEPCs could be inhibited by Noggin. CONCLUSION Thus, the present study demonstrates for the first time that BMP4-related signaling pathway is essential with endothelial repair capacity of LEPCs in human. The upregulation of BMP4-modified signaling pathway in human LEPCs may be a novel therapeutic strategy for endothelial repair after injury.