Histamine induces chemotaxis and phagocytosis in murine bone marrow-derived macrophages and RAW 264.7 macrophage-like cells via histamine H4-receptor

Expression and function of histamine H4-receptor, an immunomodulatory receptor involved in inflammatory diseases, on murine macrophages, which are vital for immunity, were investigated. The expression pattern of histamine receptors on bone marrow-derived macrophages of BALB/c mice and on RAW 264.7 cells was studied at the mRNA level by reverse transcription polymerase chain reaction. The functional relevance of histamine receptors was investigated by analyzing histamine-induced chemotaxis and phagocytosis in the presence of histamine receptor antagonists mepyramine (histamine H1-receptor), famotidine (histamine H2-receptor), thioperamide (histamine H3/4-receptors) and JNJ7777120 (histamine H4-receptor). Both bone marrow-derived macrophages and RAW 264.7 cells express mRNA for histamine H1-receptor and histamine H4-receptor. Residual amounts of histamine H2-receptor mRNA are found in bone marrow-derived macrophages only. In both cellular models, histamine induced chemotaxis and phagocytic activity, which was reduced by thioperamide as well as by JNJ 7777120, but not by mepyramine or famotidine. In murine bone marrow-derived macrophages and RAW 264.7 macrophage-like cells histamine H4-receptor mediates chemotaxis and phagocytic activity.