| First Author | Li K | Year | 2015 |
| Journal | Circ Res | Volume | 117 |
| Issue | 1 | Pages | e1-e11 |
| PubMed ID | 25904598 | Mgi Jnum | J:248917 |
| Mgi Id | MGI:6098868 | Doi | 10.1161/CIRCRESAHA.117.305844 |
| Citation | Li K, et al. (2015) Apolipoprotein E enhances microRNA-146a in monocytes and macrophages to suppress nuclear factor-kappaB-driven inflammation and atherosclerosis. Circ Res 117(1):e1-e11 |
| abstractText | RATIONALE: Apolipoprotein E (apoE) exerts anti-inflammatory properties that protect against atherosclerosis and other inflammatory diseases. However, mechanisms by which apoE suppresses the cellular activation of leukocytes commonly associated with atherosclerosis remain incompletely understood. OBJECTIVE: To test the hypothesis that apoE suppresses inflammation and atherosclerosis by regulating cellular microRNA levels in these leukocytes. METHODS AND RESULTS: An assessment of apoE expression among such leukocyte subsets in wild-type mice revealed that only macrophages and monocytes express apoE abundantly. An absence of apoE expression in macrophages and monocytes resulted in enhanced nuclear factor-kappaB signaling and an exaggerated inflammatory response on stimulation with lipopolysaccharide. This correlated with reduced levels of microRNA-146a, a critical negative regulator of nuclear factor-kappaB signaling. Ectopic apoE expression in Apoe(-/-) macrophages and monocytes raised miR-146a levels, whereas its silencing in wild-type cells had an opposite effect. Mechanistically, apoE increased the expression of transcription factor purine-rich PU-box-binding protein 1, which raised levels of pri-miR-146 transcripts, demonstrating that apoE exerts transcriptional control over miR-146a. In vivo, even a small amount of apoE expression in macrophages and monocytes of hypomorphic apoE mice led to increased miR-146a levels, and inhibited macrophage proinflammatory responses, Ly-6C(high) monocytosis, and atherosclerosis in the settings of hyperlipidemia. Accordingly, cellular enrichment of miR-146a through the systemic delivery of miR-146a mimetics in Apoe(-/-)Ldlr(-/-) and Ldlr(-/-) mice attenuated monocyte/macrophage activation and atherosclerosis in the absence of plasma lipid reduction. CONCLUSIONS: Our data demonstrate that cellular apoE expression suppresses nuclear factor-kappaB-mediated inflammation and atherosclerosis by enhancing miR-146a levels in monocytes and macrophages. |
