Cysteinyl leukotrienes induce monocyte chemoattractant protein 1 in human monocytes/macrophages

BACKGROUND: Monocytes/macrophages have a cysteinyl leukotriene 1 (CysLT1) receptor, but its function is poorly understood. Objective To elucidate the biological function of the CysLT1 receptor of human monocytes/macrophages. METHODS: We examined the production of TNF-alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, monocyte chemoattractant protein 1 (MCP-1), macrophage colony-stimulating factor (M-CSF), and eotaxin induced by CysLTs (leukotriene (LT)C4, -D4, and -E4) in THP-1 cells, a human monocytic leukaemia cell line, and peripheral blood CD14+ monocytes/macrophages. Moreover, we examined the effect of CysLTs on the expression of beta-chemokine receptor 2B (CCR2B) as the receptor of MCP-1 by Western blot analysis. RESULTS: ELISA revealed that CysLTs induced MCP-1 in THP-1 cells and peripheral blood CD14+ monocytes/macrophages, but not other cytokines. PCR demonstrated that CysLTs increased MCP-1 mRNA expression in THP-1 cells, and Western blotting showed that CysLTs increased the expression of CCR2B in THP-1 cells. Moreover, we demonstrated that pranlukast, a CysLT1 receptor antagonist, blocked MCP-1 production by CysLTs in THP-1 cells almost completely, and partially inhibited MCP-1 release by CysLTs in peripheral blood CD14+ monocytes/macrophages and CCR2B expression by CysLTs in THP-1 cells. CONCLUSION: CysLTs induce MCP-1 and increase CCR2B expression in human monocytes/macrophages.