Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China.
Department of Endocrinology, The Second Affiliated Hospital, Xi'an Jiaotong University, 157 Fifth West Road, Xi'an 710004, Shaanxi, China.
Exp Cell Res. 2018 Aug 15;369(2):208-217. doi: 10.1016/j.yexcr.2018.05.020. Epub 2018 May 21.
Monocyte migration into diseased tissues contributes to the pathogenesis of diseases. Intermediate-conductance Ca-activated K (K3.1) channels play an important role in cell migration. However, the role of K3.1 channels in mediating monocyte migration induced by palmitic acid (PA) is still unclear. Using cultured THP-1 cells and peripheral blood mononuclear cells from healthy subjects, we investigated the role and signaling mechanisms of K3.1 channels in mediating the migration induced by PA. Using methods of Western blotting analysis, RNA interference, cell migration assay and ELISA, we found that PA-treated monocytes exhibited increment of the protein levels of K3.1 channel and monocyte chemoattractant protein-1 (MCP-1), and the effects were reversed by co-incubation of PA with anti-TLR2/4 antibodies or by specific inhibitors of p38-MAPK, or NF-κB. In addition, PA increased monocyte migration, which was abolished by a specific K3.1 channel blocker, TRAM-34, or K3.1 small interfering RNA (siRNA). The expression and secretion of MCP-1 induced by PA was also similarly prevented by TRAM-34 and K3.1 siRNA. These results demonstrate for the first time that PA upregulates K3.1 channels through TLR2/4, p38-MAPK and NF-κB pathway to promote the expression of MCP-1, and then induce the trans-endothelial migration of monocytes.
单核细胞迁移到病变组织中有助于疾病的发病机制。中等电导钙激活钾 (K3.1) 通道在细胞迁移中起重要作用。然而，K3.1 通道在介导棕榈酸 (PA) 诱导的单核细胞迁移中的作用尚不清楚。使用培养的 THP-1 细胞和来自健康受试者的外周血单核细胞，我们研究了 K3.1 通道在介导 PA 诱导的迁移中的作用和信号机制。通过 Western blot 分析、RNA 干扰、细胞迁移测定和 ELISA，我们发现 PA 处理的单核细胞表现出 K3.1 通道和单核细胞趋化蛋白-1 (MCP-1) 的蛋白水平增加，并且这些作用通过与 PA 共孵育抗 TLR2/4 抗体或 p38-MAPK 或 NF-κB 的特异性抑制剂来逆转。此外，PA 增加单核细胞迁移，这被特异性 K3.1 通道阻滞剂 TRAM-34 或 K3.1 小干扰 RNA (siRNA) 所消除。PA 诱导的 MCP-1 的表达和分泌也被 TRAM-34 和 K3.1 siRNA 类似地阻止。这些结果首次表明，PA 通过 TLR2/4、p38-MAPK 和 NF-κB 通路上调 K3.1 通道，促进 MCP-1 的表达，从而诱导单核细胞的跨内皮迁移。
