Kruppel-Like Factor 2-Mediated Suppression of MicroRNA-155 Reduces the Proinflammatory Activation of Macrophages

• Published in: PloS one 2015-09, Vol.10 (9), p.e0139060-e0139060
• Main Authors: He, Shaolin, Yang, Liyuan, Li, Dazhu, Li, Ming
• Format: Article
• Language: English
• Subjects: Animals; Aorta; Aortic arch; Apolipoprotein E; Arteriosclerosis; Atherosclerosis; Binding sites; Bone marrow; Cardiology; Cell activation; Cells, Cultured; Chemokine CCL2 - genetics; Chemokine CCL2 - metabolism; Copper; Development and progression; Endothelial cells; Gene expression; Genetic aspects; Hospitals; Humans; Inflammation; Inflammatory response; Interleukin 10; Interleukins - genetics; Interleukins - metabolism; Krueppel-like factor; Kruppel-Like Transcription Factors - genetics; Kruppel-Like Transcription Factors - metabolism; Lesions; Lipoproteins; Low density lipoprotein; Macrophage Activation; Macrophages; Macrophages - immunology; Macrophages - metabolism; Mice; Mice, Inbred C57BL; MicroRNA; MicroRNAs; MicroRNAs - genetics; miRNA; Monocyte chemoattractant protein; Monocyte chemoattractant protein 1; Monocytes; Overexpression; Oxidation; Pathogenesis; Peritoneum; Physiological aspects; Plaque, Atherosclerotic - metabolism; Polymerase chain reaction; Prevention; Proteins; Ribonucleic acid; RNA; siRNA
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0139060

Recent evidence indicates that significant interactions exist between Kruppel-like factor 2 (KLF2) and microRNAs (miRNAs) in endothelial cells. Because KLF2 is known to exert anti-inflammatory effects and inhibit the pro-inflammatory activation of monocytes, we sought to identify how inflammation-associated miR-155 is regulated by KLF2 in macrophages. Peritoneal macrophages from wild-type (WT) C57Bl/6 mice were transfected with either recombinant adenovirus vector expressing KLF2 (Ad-KLF2) or siRNA targeting KLF2 (KLF2-siRNA) for 24 h-48 h, then stimulated with oxidized low-density lipoproteins (ox-LDL, 50 μg/mL) for 24 h. Quantitative real-time polymerase chain reaction showed that KLF2 markedly reduced the expression of miR-155 in quiescent/ox-LDL-stimulated macrophages. We also found that the increased expression of miR-155, monocyte chemoattractant protein (MCP-1) and interleukin (IL)-6 and the decreased expression of the suppressor of cytokine signaling (SOCS)-1 and IL-10 in ox-LDL-treated macrophages were significantly suppressed by KLF2. Most importantly, over-expression of miR-155 could partly reverse the suppressive effects of KLF2 on the inflammatory response of macrophages. Conversely, the suppression of miR-155 in KLF2 knockdown macrophages significantly overcame the pro-inflammatory properties associated with KLF2 knockdown. Finally, Ad-KLF2 significantly attenuated the diet-induced formation of atherosclerotic lesions in apolipoprotein E-deficient (apoE(-/-)) mice, which was associated with a significantly reduced expression of miR-155 and its relative inflammatory cytokine genes in the aortic arch and in macrophages. KLF2-mediated suppression of miR-155 reduced the inflammatory response of macrophages.