Systemic Delivery of MicroRNA-181b Inhibits Nuclear Factor-κB Activation, Vascular Inflammation, and Atherosclerosis in Apolipoprotein E–Deficient Mice

Abstract

Rationale Activated nuclear factor (NF)-κB signaling in the vascular endothelium promotes the initiation and progression of atherosclerosis. Targeting endothelial NF-κB may provide a novel strategy to limit chronic inflammation. Objective To examine the role of microRNA-181b (miR-181b) in endothelial NF-κB signaling and effects on atherosclerosis. Methods and Results MiR-181b expression was reduced in the aortic intima and plasma in apolipoprotein E–deficient mice fed a high-fat diet. Correspondingly, circulating miR-181b in the plasma was markedly reduced in human subjects with coronary artery disease. Systemic delivery of miR-181b resulted in a 2.3-fold overexpression of miR-181b in the aortic intima of apolipoprotein E–deficient mice and suppressed NF-κB signaling revealed by bioluminescence imaging and reduced target gene expression in the aortic arch in apolipoprotein E–deficient/NF-κB-luciferase transgenic mice. MiR-181b significantly inhibited atherosclerotic lesion formation, proinflammatory gene expression and the influx of lesional macrophages and CD4+ T cells in the vessel wall. Mechanistically, miR-181b inhibited the expression of the target gene importin-α3, an effect that reduced NF-κB nuclear translocation specifically in the vascular endothelium of lesions, whereas surprisingly leukocyte NF-κB signaling was unaffected despite a 7-fold overexpression of miR-181b. Our findings uncover that NF-κB nuclear translocation in leukocytes does not involve importin-α3, but rather importin-α5, which miR-181b does not target, highlighting that inhibition of NF-κB signaling in the endothelium is sufficient to mediate miR-181b's protective effects. Conclusions Systemic delivery of miR-181b inhibits the activation of NF-κB and atherosclerosis through cell-specific mechanisms in the vascular endothelium. These findings support the rationale that delivery of miR-181b may provide a novel therapeutic approach to treat chronic inflammatory diseases such as atherosclerosis.

miRNAs and lncRNAs in vascular injury and remodeling

“…Over-expression of miR-181b inhibits the expression of NF-κB responsive genes in endothelial cells, such as VCAM-1 and E-selectin, by directly suppressing importin-α3, a protein required for nuclear translocation of NF-κB [47]. These findings suggest that systemic delivery of miR-181b in vivo can suppress the progression of atherosclerosis [48]. These observations suggest that regulation of miRNAs might provide a novel therapeutic approach for atherosclerosis.…”

The interplay of LncRNA ANRIL and miR‐181b on the inflammation‐relevant coronary artery disease through mediating NF‐κB signalling pathway

“…Moreover, after intravenous injection of miR‐181b mimic into atherosclerosis mice, the convergence of macrophages, CD 4+ T cells and other inflammatory cells were held up, along with decreased expressions of inflammatory markers 11. Similar to this, our study verified that miR‐181b could induce inflammatory reactions both in vivo and in vitro, which was specifically manifested as that the expressions of IL‐6, IL‐8, TNF‐α, iNOS, ICAM‐1, VCAM‐1, COX‐2 were down‐regulated (Figures 5 and 8).…”

“…In addition, the function of lncRNAs was often mediated through the regulation of microRNAs (miRNAs), which post‐transcriptionally regulate gene expression by binding to the 3′ untranslated region (UTR) of mRNAs 10. For instance, it was documented that ANRIL modifying miR‐181b could boost a series of vicious transformations that were relevant to human vascular inflammation 11. However, whether ANRIL would impact on miR‐181b to regulate the onset or progression of CAD remained unanswered.…”

MicroRNA‐181b inhibits thrombin‐mediated endothelial activation and arterial thrombosis by targeting caspase recruitment domain family member 10

“…Tail-vein injection of lipofectamine-encapsulated miRNA or siRNA into mice Mice were injected with microRNA mimics or siRNAs 3 times by tail vein injection on 3 consecutive days as previously described (20).…”

“…We have previously uncovered an important role of microRNA181b (miR-181b) in regulation of both acute and chronic vascular inflammation (20,21) by reducing downstream NF-kB signaling. miR-181b has no effect on upstream NFkB signaling, such as IKK-b and IkBa phosphorylation in response to TNF-a in ECs.…”