IL-10 negatively regulates oxLDL-P38 pathway inhibited macrophage emigration

The effect of IL-10 on macrophage migration was investigated, including the analysis of protein expression, cytokine secretion and activation of the MAPKs and NF-kB pathway. The expression of endogenic IL-10 was down-regulated in macrophage stimulated with oxLDL for indicated time. Exogenous IL-10 reversed oxLDL-inhibited chemotactic macrophage numbers by 48.18 ± 4.93% (3h), 64.8 ± 5.61% (6h) and 63.66 ± 3.05% (12h), and pretreated with SB203580 (P38 signaling inhibitor) in macrophage, oxLDL could not inhibit macrophage emigration. IL-10 significantly decreased oxLDL-mediated increase of SR-A expression, and pretreatment with β-arrestin2 RNAi in macrophage could not change oxLDL-induced SR-A expression. IL-10 also significantly decreased oxLDL-mediated increase of β-arrestin2 expression, and pre-treated with SR-A RNAi in macrophage, oxLDL could not induce the increase of β-arrestin2 expression. However, IL-10 significantly reversed oxLDL-mediated inhibition of CCR7 expression about 95.7 8 ± 0.99% (mRNA) and 80.06 ± 19.46% (protein), and pretreated with P38 inhibitor SB203580 in macrophage, oxLDL could not decrease CCR7 expression. IL-10 inhibited oxLDL-mediated inhibition of MMP9 secretion about 74.02 ± 22.35%, and pretreated with P38 inhibitor SB203580 in macrophage, oxLDL could not decrease MMP9 secretion. Treatment with oxLDL increased P38-phosphorylation by 31.88 ± 2.79%, 40.24 ± 5.69% and 30.93 ± 4.66% at 15, 30 and 60 min, respectively, whereas the effect of IL-10 on the expression of phosphorylated P38 was reversed by 49.49 ± 12.12%, 70.93 ± 16.14% and 47.62 ± 6.00% in up-indicated time-points, respectively. From these data, we speculated oxLDL-SR-A-β-arrestin2-P38-MMP9/CCR7 could play a critical role in the macrophages migration, which was blocked by IL-10 through inhibiting oxLDL uptake.