title: Inhibition of macrophage functions by the C-terminus of murine S100A9 is dependent on B-1 cells.
abstract: The protein S100A9 plays a key role in the control of inflammatory response. The C-terminus of the murine S100A9 protein (mS100A9p) downregulates the spreading and phagocytic activity of adherent peritoneal cells. Murine peritoneal cells are constituted by macrophages and B-1 cells, and the latter exert an inhibitory effect on macrophage functions by secreting interleukin- (IL-) 10. Here, we investigated the influence of B-1 cells on the inhibitory effect evoked by mS100A9p on macrophages. mS100A9p did not alter spreading and phagocytosis either by peritoneal macrophages obtained from mice deprived of B-1 cells or by bone marrow-derived macrophages (BMDMϕ). Nevertheless, when BMDMϕ were cocultivated by direct or indirect contact with B-1 cells treated with mS100A9p, the phagocytosis by BMDMϕ was decreased, showing that the effect of mS100A9p on macrophages was modulated by B-1 cells and/or their secretory compounds. Furthermore, the inhibitory action of mS100A9p on phagocytosis by adherent peritoneal cells was abolished in cells obtained from IL-10 knockout mice. Taken together, the results show that mS100A9p has no direct inhibitory effect on macrophages; however, mS100A9p modulates B-1 cells, which in turn downregulates macrophages, at least in part, via IL-10. These data contribute to the characterization of S100A9 functions involving B-1 cells in the regulation of the inflammatory process.
authors.affiliation: Laboratory of Pathophysiology, Butantan Institute, Avenida Vital Brazil 1500, Butantã, 05503-000 São Paulo, SP, Brazil ; Laboratory of Neuromodulation and Experimental Pain, Hospital Sírio-Libanês, Rua Coronel Nicolau dos Santos 69, Bela Vista, 01308-060 São Paulo, SP, Brazil.
authors.forename: Rosana Lima
authors.initials: RL
authors.lastname: Pagano
authors.affiliation: Laboratory of Pathophysiology, Butantan Institute, Avenida Vital Brazil 1500, Butantã, 05503-000 São Paulo, SP, Brazil.
authors.forename: Natassja Foizer
authors.initials: NF
authors.lastname: Moraes
authors.affiliation: Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, Vila Clementino, 04023-900 São Paulo, SP, Brazil ; Discipline of Immunology, Centro Universitário São Camilo, Ipiranga, 04263-200 São Paulo, SP, Brazil.
authors.forename: Beatriz Helena
authors.initials: BH
authors.lastname: De Lorenzo
authors.affiliation: Laboratory of Pathophysiology, Butantan Institute, Avenida Vital Brazil 1500, Butantã, 05503-000 São Paulo, SP, Brazil.
authors.forename: Sandra
authors.initials: S
authors.lastname: Coccuzzo Sampaio
authors.affiliation: Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, Vila Clementino, 04023-900 São Paulo, SP, Brazil ; Discipline of Immunology, Universidade Paulista, Vila Clementino, 04026-002 São Paulo, SP, Brazil.
authors.forename: Mario
authors.initials: M
authors.lastname: Mariano
authors.affiliation: Laboratory of Pathophysiology, Butantan Institute, Avenida Vital Brazil 1500, Butantã, 05503-000 São Paulo, SP, Brazil.
authors.forename: Renata
authors.identifier: 0000-0001-6610-0838
authors.initials: R
authors.lastname: Giorgi
mesh_terms: D000818:Animals; D016175:B-Lymphocyte Subsets / Q000187:drug effects / Q000378:metabolism; D040502:Calgranulin B / Q000737:chemistry*; D002460:Cell Line; D002478:Cells, Cultured; D016753:Interleukin-10 / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D010587:Phagocytosis / Q000187:drug effects
chemical_list: D040502:Calgranulin B; D010455:Peptides; D016753:Interleukin-10