Shear stress-induced activation of Tie2-dependent signaling pathway enhances reendothelialization capacity of early endothelial progenitor cells.
Although endothelial progenitor cells (EPCs) play a pivotal role in the endothelial repair following arterial injury and shear stress has a beneficial effect on EPCs, however, the molecular mechanism underlying the influence of EPCs on the endothelial integrity and the regulation of shear stress on the EPC signaling remained to be studied. Here, we investigated the effects of laminar shear stress on the tyrosine kinase with immunoglobulin and epidermal growth factor homology domain-2 (Tie2)-dependent signaling and its relation to in vivo reendothelialization capacity of human early EPCs. The human early EPCs were treated with shear stress. Shear stress in a dose-dependent manner increased angiopoietin-2 (Ang2)-induced migratory, adhesive and proliferatory activities of EPCs. Transplantation of EPCs treated by shear stress facilitated in vivo reendothelialization in nude mouse model of carotid artery injury. In parallel, the phosphorylation of Tie2 and Akt of EPCs in response to shear stress was significantly enhanced. With treatment of Tie2 knockdown or Akt inhibition, shear stress-induced phosphorylation of Akt and endothelial nitric oxide synthase (eNOS) of EPCs was markedly suppressed. After Tie2/PI3K/Akt/eNOS signaling was blocked, the effects of shear stress on in vitro function and in vivo reendothelialization capacity of EPCs were significantly inhibited. The present findings demonstrate for the first time that Tie2/PI3k/Akt/eNOS signaling pathway is, at least in part, involved in the EPCs-mediated reendothelialization after arterial injury. The upregulation of shear stress-induced Tie2-dependent signaling contributes to enhanced in vivo reendothelialization capacity of human EPCs.
Department of Hypertension and Vascular Disease, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China.
Zhen
Z
Yang
Wen-Hao
WH
Xia
Yuan-Yuan
YY
Zhang
Shi-Yue
SY
Xu
Xing
X
Liu
Xiao-Yu
XY
Zhang
Bing-Bo
BB
Yu
Yan-Xia
YX
Qiu
Jun
J
Tao
D000818:Animals; D001773:Blood Cells / Q000201:enzymology / Q000502:physiology; D020212:Carotid Artery Injuries / Q000473:pathology / Q000628:therapy; D002342:Carotid Artery, External / Q000473:pathology / Q000502:physiology*; D002468:Cell Physiological Phenomena; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology / Q000502:physiology; D004730:Endothelium, Vascular / Q000473:pathology / Q000503:physiopathology*; D004789:Enzyme Activation; D015870:Gene Expression; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D042787:Receptor, TIE-2 / Q000235:genetics / Q000378:metabolism*; D012038:Regeneration; D015398:Signal Transduction; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000201:enzymology / Q000502:physiology*; D013312:Stress, Physiological
C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D042787:Receptor, TIE-2; D051057:Proto-Oncogene Proteins c-akt