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1668086 
Journal Article 
Regulation of Vascular Smooth Muscle Cell Turnover by Endothelial Cell-Secreted MicroRNA-126: Role of Shear Stress 
Zhou, J; Li, YS; Nguyen, P; Wang, KC; Weiss, A; Kuo, YC; Chiu, JJ; Shyy, JY; Chien, S 
2013 
Yes 
Circulation Research
ISSN: 0009-7330
EISSN: 1524-4571 
113 
1 
40-51 
English 
23603512 
WOS:000320985200013 
Rationale: Endothelial microRNA-126 (miR-126) modulates vascular development and angiogenesis. However, its role in the regulation of smooth muscle cell (SMC) function is unknown. Objective: To elucidate the role of miR-126 secreted by endothelial cells (ECs) in regulating SMC turnover in vitro and in vivo, as well as the effects of shear stress on the regulation. Methods and Results: Coculture of SMCs with ECs or treatment of SMCs with conditioned media from static EC monoculture (EC-CM) increased SMC miR-126 level and SMC turnover; these effects were abolished by inhibition of endothelial miR-126 and by the application of laminar shear stress to ECs. SMC miR-126 did not increase when treated with EC-CM from ECs subjected to inhibition of miR biogenesis, or with CM from sheared ECs. Depletion of extracellular/secreted vesicles in EC-CM did not affect the increase of SMC miR-126 by EC-CM. Biotinylated miR-126 or FLAG (DYKDDDDK epitope)-tagged Argonaute2 transfected into ECs was detected in the cocultured or EC-CM-treated SMCs, indicating a direct EC-to-SMC transmission of miR-126 and Argonaute2. Endothelial miR-126 represses forkhead box O3, B-cell lymphoma 2, and insulin receptor substrate 1 mRNAs in the cocultured SMCs, suggesting the functional roles of the transmitted miR-126. Systemic depletion of miR-126 in mice inhibited neointimal lesion formation of carotid arteries induced by cessation of blood flow. Administration of EC-CM or miR-126 mitigated the inhibitory effect. Conclusions: Endothelial miR-126 acts as a key intercellular mediator to increase SMC turnover, and its release is reduced by atheroprotective laminar shear stress. 
atherosclerosis; endothelial cell; extracellular miR-126; shear stress; smooth muscle cell