MicroRNA-21 targets peroxisome proliferators-activated receptor-alpha in an autoregulatory loop to modulate flow-induced endothelial inflammation.

Abstract

Adhesion of circulating monocytes to vascular endothelial cells (ECs) is a critical event leading to vascular inflammation and, hence, development of atherosclerosis. MicroRNAs (miRs) are a class of endogenous, highly conserved, noncoding small RNAs that play important roles in regulating gene expression and cellular function, as well as pathogenesis of atherosclerosis. Here, we showed that oscillatory shear stress (OSS) induces the expression of miR-21 at the transcriptional level in cultured human umbilical vein ECs via an increased binding of c-Jun, which is a component of transcription factor activator protein-1 (AP-1), to the promoter region of miR-21. OSS induction of miR-21 inhibited the translation, but not transcription, of peroxisome proliferators-activated receptor-α (PPARα) by 3'-UTR targeting. Overexpression of miR-21 up-regulated AP-1 activation, which was attenuated by exogenous expression of PPARα. OSS and overexpression of miR-21 enhanced the expression of adhesion molecules vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 and the consequential adhesion of monocytes to ECs. Overexpression of PPARα significantly attenuated the AP-1-mediated miR-21 expression. These results demonstrate a unique mechanism by which OSS induces AP-1-dependent miR-21 expression, which directly targets PPARα to inhibit its expression, thereby allowing activation of AP-1 and the promotion of monocyte adhesion. Our findings suggest the presence of a positive feedback loop that enables the sustained induction of miR-21, thus contributing to the proinflammatory responses of vascular endothelium under OSS.

• Authors: Jing Zhou, Kuei-Chun Wang, Wei Wu, Shankar Subramaniam, John Y-J Shyy, Jeng-Jiann Chiu, Julie Y-S Li, Shu Chien
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 108 Issue 25 Pg. 10355-60 (Jun 21 2011) ISSN: 1091-6490 [Electronic] United States
• PMID: 21636785 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• MIRN21 microRNA, human
• MicroRNAs
• PPAR alpha
• Transcription Factor AP-1

Topics

• Endothelium, Vascular (metabolism, pathology)
• Feedback, Physiological (physiology)
• Gene Expression Regulation
• HeLa Cells
• Humans
• Inflammation (metabolism, pathology)
• MicroRNAs (genetics, metabolism)
• PPAR alpha (genetics, metabolism)
• Stress, Mechanical
• Transcription Factor AP-1 (metabolism)
• Transcriptional Activation