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MicroRNA-23b regulates cyclin-dependent kinase-activating kinase complex through cyclin H repression to modulate endothelial transcription and growth under flow.

  • Author(s): Wang, Kuei-Chun;
  • Nguyen, Phu;
  • Weiss, Anna;
  • Yeh, Yi-Ting;
  • Chien, Hou Su;
  • Lee, Alicia;
  • Teng, Dayu;
  • Subramaniam, Shankar;
  • Li, Yi-Shuan;
  • Chien, Shu
  • et al.
Abstract

Objective

The site-specificity of endothelial phenotype is attributable to the local hemodynamic forces. The flow regulation of microRNAs in endothelial cells (ECs) plays a significant role in vascular homeostasis and diseases. The objective of this study was to elucidate the molecular mechanism by which the pulsatile shear flow-induced microRNA-23b (miR-23b) exerts antiproliferative effects on ECs.

Approach and results

We used a combination of a cell perfusion system and experimental animals to examine the flow regulation of miR-23b in modulating EC proliferation. Our results demonstrated that pulsatile shear flow induces the transcription factor Krüppel-like factor 2 to promote miR-23b biosynthesis; the increase in miR-23b then represses cyclin H to impair the activity and integrity of cyclin-dependent kinase-activating kinase (CAK) complex. The inhibitory effect of miR-23b on CAK exerts dual actions to suppress cell cycle progression, and reduce basal transcription by deactivating RNA polymerase II. Whereas pulsatile shear flow regulates the miR-23b/CAK pathway to exert antiproliferative effects on ECs, oscillatory shear flow has little effect on the miR-23b/CAK pathway and hence does not cause EC growth arrest. Such flow pattern-dependent phenomena are validated with an in vivo model on rat carotid artery: the flow disturbance induced by partial carotid ligation led to a lower expression of miR-23b and a higher EC proliferation in comparison with the pulsatile flow regions of the unligated vessels. Local delivery of miR-23b mitigated the proliferative EC phenotype in partially ligated vessels.

Conclusions

Our findings unveil a novel mechanism by which hemodynamic forces modulate EC proliferative phenotype through the miR-23b/CAK pathway.

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