title: Heme Oxygenase-1 expression in M-CSF-polarized M2 macrophages contributes to LPS-induced IL-10 release.
abstract: The shift between pro-inflammatory (M1) and anti-inflammatory (M2) states of macrophage polarization allows the resolution of inflammatory processes as well as the maintenance of a basal anti-inflammatory environment in tissues continuously exposed to harmless antigens (e.g., lung and gut). To identify markers for the anti-inflammatory state of macrophages, expression profiling was performed on human macrophages polarized by either GM-CSF or M-CSF, which lead to the generation of TNF-alpha and IL-12p40-producing pro-inflammatory macrophages [M1 (GM-CSF)] or IL-10-producing anti-inflammatory macrophages [M2 (M-CSF)] upon exposure to LPS, respectively. A different iron metabolism gene signature was detected in both macrophage types, with the heme regulatory molecules CD163 and Heme Oxygenase-1 (HO-1) being preferentially expressed by M2 (M-CSF) macrophages. M1-polarizing cytokines (GM-CSF, IFNgamma) inhibited, while IL-4 enhanced, the M-CSF-driven HO-1 expression. In agreement with this in vitro data, HO-1 expression in metastatic melanoma was primarily detected in CD163(+) tumor-associated macrophages, which are known to exhibit an M2-skewed polarization phenotype. In contrast to the HO-1 inhibitor tin protoporphyrin (SnPP), the administration of cobalt protoporphyrin (CoPP), a potent inducer of HO-1 resulted in increased LPS-triggered IL-10 release from M2 (M-CSF) macrophages. The data suggests that HO-1 is important for the anti-inflammatory activities of M-CSF-polarized M2 macrophages. Moreover, since M2 (M-CSF) macrophages also express higher levels of the CD163 scavenger receptor, the CD163/HO-1/IL-10 axis appears to contribute to the generation of an immunosuppressive environment within the tumor stroma.
authors.affiliation: Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Sierra-Filardi
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Vega
authors.forename: Paloma
authors.initials: P
authors.lastname: Sánchez-Mateos
authors.forename: Angel L
authors.initials: AL
authors.lastname: Corbí
authors.forename: Amaya
authors.initials: A
authors.lastname: Puig-Kröger
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D015214:Antigens, Differentiation, Myelomonocytic / Q000096:biosynthesis / Q000235:genetics; D015415:Biomarkers / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D053762:Interleukin-12 Subunit p40 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D008665:Metalloporphyrins / Q000494:pharmacology; D009362:Neoplasm Metastasis; D011524:Protoporphyrins / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D000098902:CD163 Antigen; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides; D008665:Metalloporphyrins; D011524:Protoporphyrins; D011956:Receptors, Cell Surface; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; C007095:cobaltiprotoporphyrin; D016173:Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; C032628:tin protoporphyrin IX; D051547:Heme Oxygenase-1