MicroRNA-181b regulates NF-κB–mediated vascular inflammation
Xinghui Sun, … , Rebecca M. Baron, Mark W. Feinberg
Xinghui Sun, … , Rebecca M. Baron, Mark W. Feinberg
Published May 24, 2012
Citation Information: J Clin Invest. 2012;122(6):1973-1990. https://doi.org/10.1172/JCI61495.
View: Text | PDF
Research Article

MicroRNA-181b regulates NF-κB–mediated vascular inflammation

Abstract

EC activation and dysfunction have been linked to a variety of vascular inflammatory disease states. The function of microRNAs (miRNAs) in vascular EC activation and inflammation remains poorly understood. Herein, we report that microRNA-181b (miR-181b) serves as a potent regulator of downstream NF-κB signaling in the vascular endothelium by targeting importin-α3, a protein that is required for nuclear translocation of NF-κB. Overexpression of miR-181b inhibited importin-α3 expression and an enriched set of NF-κB–responsive genes such as adhesion molecules VCAM-1 and E-selectin in ECs in vitro and in vivo. In addition, treatment of mice with proinflammatory stimuli reduced miR-181b expression. Rescue of miR-181b levels by systemic administration of miR-181b “mimics” reduced downstream NF-κB signaling and leukocyte influx in the vascular endothelium and decreased lung injury and mortality in endotoxemic mice. In contrast, miR-181b inhibition exacerbated endotoxin-induced NF-κB activity, leukocyte influx, and lung injury. Finally, we observed that critically ill patients with sepsis had reduced levels of miR-181b compared with control intensive care unit (ICU) subjects. Collectively, these findings demonstrate that miR-181b regulates NF-κB–mediated EC activation and vascular inflammation in response to proinflammatory stimuli and that rescue of miR-181b expression could provide a new target for antiinflammatory therapy and critical illness.

Authors

Xinghui Sun, Basak Icli, Akm Khyrul Wara, Nathan Belkin, Shaolin He, Lester Kobzik, Gary M. Hunninghake, Miguel Pinilla Vera, Timothy S. Blackwell, Rebecca M. Baron, Mark W. Feinberg

×

Figure 2

miR-181b represses TNF-α–induced proinflammatory gene expression in vivo.

Options: View larger image (or click on image) Download as PowerPoint
miR-181b represses TNF-α–induced proinflammatory gene expression in vivo...
(A) Mice were i.v. injected with vehicle, miRNA negative control, or miR-181b mimics (50 μg/mouse). Twenty-four hours later, mice were treated with or without TNF-α for 4 hours, and lungs were harvested for Western blot analysis of VCAM-1 protein levels. Densitometry was performed and fold change of protein expression was quantified. (B) Experiments were carried out as described in A, and real-time qPCR analysis of VCAM-1 mRNA level in indicated tissues was performed. (C) VCAM-1 staining of lung and aorta sections. Mice were treated as in A. Scale bars: 25 μm (insets, 10 μm). (D and E) Quantification of VCAM-1 staining in lung and aortic endothelium, respectively. (A–E) Vehicle group (n = 3 mice), miRNA negative control group (n = 5 mice), miR-181b mimics group (n = 5 mice). Data represent mean ± SEM. (F) Ultrasound image shows region of interest (innominate artery) for in vivo VCAM-1 imaging using microbubble contrast. (G–I) Mice were injected with vehicle, miRNA negative control (n = 7), or miR-181b mimics (n = 6). Representative images show the differential targeted enhancement values for VCAM-1 expression detected by ultrasound before and after microbubble burst. (J) Quantification of differential targeted enhancement values for VCAM-1 expression in mice injected with miRNA negative control or miR-181b mimics. Data represent mean ± SEM. *P < 0.05.