title: 7-Oxo-cholesterol potentiates pro-inflammatory signaling in human M1 and M2 macrophages.
abstract: Macrophages, the major cellular components of atherosclerotic plaques, consist of two main subsets: the pro-inflammatory, M1 or classically activated macrophages, and the anti-inflammatory, M2 or alternatively activated macrophages. The molecular and cellular mechanisms that orchestrate the macrophage polarization and activation that may play a role in plaque progression and stability are poorly understood. Recent studies suggest that oxysterols, oxidative stress-mediated cholesterol oxidation products that are abundant in atherosclerotic lesions, may affect macrophage biology. We investigated whether 7-oxo-cholesterol (7oxo-C) affected polarized human M1 and M2 macrophage phenotypes and functions. Monocyte-derived M1 and M2 macrophages were challenged with 7oxo-C and their phenotype analyzed using flow cytometric analysis, and their function via secretome profiling, the presence of endocytosis and matrix metalloproteinase-9 (MMP-9) release. 7oxo-C increased the expression of HLA-DR in M1 macrophages, and CD14 on M2 macrophages. The oxysterol also reduced CD16 expression on M1 macrophages, while reducing their endocytotic capability and increasing MMP-9 secretion in M2 macrophages. Secretome profiling from cultured cell supernatants showed that 7oxo-C stimulated the production of key pro-atherogenic mediators involved in pro-inflammatory, pro-invasive and pro-angiogenic mechanisms both in M1 and M2 cells. Hypoxic conditions potentiated the effects of 7oxo-C on M1 and M2 cells. The ability of 7oxo-C to polarize macrophages toward a pro-inflammatory state represents a potentially novel mechanism by which oxidative stress can contribute to atherosclerotic lesion progression.
authors.affiliation: Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Brigitta
authors.initials: B
authors.lastname: Buttari
authors.forename: Luca
authors.initials: L
authors.lastname: Segoni
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Profumo
authors.forename: Daniela
authors.initials: D
authors.lastname: D'Arcangelo
authors.forename: Stefania
authors.initials: S
authors.lastname: Rossi
authors.forename: Francesco
authors.initials: F
authors.lastname: Facchiano
authors.forename: Rita
authors.initials: R
authors.lastname: Businaro
authors.forename: Luigi
authors.initials: L
authors.lastname: Iuliano
authors.forename: Rachele
authors.initials: R
authors.lastname: Riganò
mesh_terms: D015687:Cell Hypoxia; D016764:Cell Polarity; D002470:Cell Survival; D016207:Cytokines / Q000378:metabolism; D004705:Endocytosis; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D007653:Ketocholesterols / Q000378:metabolism* / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D016207:Cytokines; D007653:Ketocholesterols; D042461:Vascular Endothelial Growth Factor A; D016179:Granulocyte Colony-Stimulating Factor; D020780:Matrix Metalloproteinase 9; C003001:7-ketocholesterol