Regulation of microRNA-126 on the polarization of human macrophages stimulated by Porphyromonas gingivalis lipopolysaccharide / 中华口腔医学杂志

ABSTRACT

Objective: To study the effect of microRNA-126 (miR-126) on the polarization of human monocyte-derived macrophages stimulated by Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS). Methods: Macrophages derived from human myeloid leukemia mononuclear cells were stimulated by Pg-LPS (5 mg/L) and by Pg-LPS (5 mg/L) after 24 h-transfection of miR-126 mimic or negative control RNA for 48 h, respectively. Real-time quantitative-PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) and Western blotting were conducted to detect the changes in miR-126, pro-inflammatory factor tumor necrosis factor-α (TNF-α), anti-inflammatory factors interleukin-10 (IL-10), inducible nitric oxide synthase (iNOS), arginase-1 (Arg-1) and M1 polarization-related pathways such as nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Results: Compared with non-LPS stimulation group (TNF-α 1.000±0.020, iNOS 1.125±0.064, miR-126 1.004±0.113, IL-10 1.003±0.053, Arg-1 1.130±0.061), the mRNA levels of TNF-α (3.105±0.278) and iNOS (4.296±0.003) increased significantly (t=6.53, P=0.003; t=42.63, P<0.001, respectively), while miR-126, IL-10 and Arg-1 expressions (0.451±0.038, 0.545±0.004 and 0.253±0.017) decreased significantly (t=7.95, P=0.001; t=7.36, P=0.002; t=11.94, P<0.001, respectively) after Pg-LPS stimulated by human-derived macrophages for 48 h. The protein expression of iNOS, TNF-α, Arg-1 and IL-10 were consistent at mRNA levels. Meanwhile, the expressions of phospho-NF-κB p65 (p-p65), phospho-extracellular signal-regulated kinase (p-ERK) and phospho-p38 MAPK (p-p38) increased significantly, while the expression of Arg-1 decreased significantly. Compared with the negative controls (scramble RNA) (TNF-α 1.141±0.197, iNOS 1.173±0.115, IL-10 1.032±0.138, Arg-1 0.933±0.044), the mRNA levels of TNF-α (0.342±0.022) and iNOS (0.588±0.085) expressions significantly decreased (t=5.35, P=0.006; t=5.05, P=0.007), while IL-10 (1.786±0.221) and Arg-1 expressions (2.152±0.229) significantly increased (t=3.71, P=0.021; t=6.21, P=0.003) after Pg-LPS stimulation with miR-126 mimic transfection. The relative protein expressions of iNOS, p-p65, p-ERK and p-p38 significantly decreased (t=13.00, P<0.001; t=6.98, P=0.002; t=10.86, P<0.001; t=8.32, P=0.001), while the protein level of Arg-1 significantly increased (t=12.08, P<0.001). Conclusions: Pg-LPS could promote M1 polarization of macrophages. miR-126 might inhibit the effect of Pg-LPS on the M1 polarization of macrophages through down-regulating NF-κB and MAPK signaling pathways.