title: Moderate Increase of Indoxyl Sulfate Promotes Monocyte Transition into Profibrotic Macrophages.
abstract: OBJECTIVE
  The uremic toxin Indoxyl-3-sulphate (IS), a ligand of Aryl hydrocarbon Receptor (AhR), raises in blood during early renal dysfunction as a consequence of tubular damage, which may be present even when eGFR is normal or only moderately reduced, and promotes cardiovascular damage and monocyte-macrophage activation. We previously found that patients with abdominal aortic aneurysms (AAAs) have higher CD14+CD16+ monocyte frequency and prevalence of moderate chronic kidney disease (CKD) than age-matched control subjects. Here we aimed to evaluate the IS levels in plasma from AAA patients and to investigate in vitro the effects of IS concentrations corresponding to mild-to-moderate CKD on monocyte polarization and macrophage differentiation.
  
  
  METHODS
  Free IS plasma levels, monocyte subsets and laboratory parameters were evaluated on blood from AAA patients and eGFR-matched controls. THP-1 monocytes, treated with IS 1, 10, 20 μM were evaluated for CD163 expression, AhR signaling and then induced to differentiate into macrophages by PMA. Their phenotype was evaluated both at the stage of semi-differentiated and fully differentiated macrophages. AAA and control sera were similarly used to treat THP-1 monocytes and the resulting macrophage phenotype was analyzed.
  
  
  RESULTS
  IS plasma concentration correlated positively with CD14+CD16+ monocytes and was increased in AAA patients. In THP-1 cells, IS promoted CD163 expression and transition to macrophages with hallmarks of classical (IL-6, CCL2, COX2) and alternative phenotype (IL-10, PPARγ, TGF-β, TIMP-1), via AhR/Nrf2 activation. Analogously, AAA sera induced differentiation of macrophages with enhanced IL-6, MCP1, TGF-β, PPARγ and TIMP-1 expression.
  
  
  CONCLUSIONS
  IS skews monocyte differentiation toward low-inflammatory, profibrotic macrophages and may contribute to sustain chronic inflammation and maladaptive vascular remodeling.
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Barisione
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Silvano
authors.initials: S
authors.lastname: Garibaldi
authors.affiliation: Giannina Gaslini Institute, Genova, Italy.
authors.forename: Anna Lisa
authors.initials: AL
authors.lastname: Furfaro
authors.affiliation: Department of Experimental Medicine, University of Genova, Genova, Italy.
authors.forename: Mariapaola
authors.initials: M
authors.lastname: Nitti
authors.affiliation: Unit of Vascular and Endovascular Surgery, University of Genova, Genova, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Palmieri
authors.affiliation: Department of Experimental Medicine, University of Genova, Genova, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Passalacqua
authors.affiliation: Department of Internal Medicine, IRCCS University Hospital San Martino, University of Genova, Genova, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Garuti
authors.affiliation: Nephrology Division, Department of Internal Medicine, IRCCS University Hospital San Martino, University of Genova, Genova, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Verzola
authors.affiliation: Centre of Excellence for Biomedical Research (CEBR), University of Genova, Genova, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Parodi
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Ameri
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Altieri
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Fabbi
authors.affiliation: Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy.
authors.forename: Pier Francesco
authors.initials: PF
authors.lastname: Ferrar
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Brunelli
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, The Ohio State University, Columbus, OH, United States of America.
authors.forename: Violeta
authors.initials: V
authors.lastname: Arsenescu
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Manrico
authors.initials: M
authors.lastname: Balbi
authors.affiliation: Unit of Vascular and Endovascular Surgery, University of Genova, Genova, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Palombo
authors.affiliation: Division of Cardiology, IRCCS University Hospital San Martino, Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Ghigliotti
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D017544:Aortic Aneurysm, Abdominal / Q000097:blood / Q000378:metabolism; D017209:Apoptosis; D015415:Biomarkers; D016022:Case-Control Studies; D002460:Cell Line; D049109:Cell Proliferation; D054338:Cell Transdifferentiation / Q000235:genetics; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D015870:Gene Expression; D005919:Glomerular Filtration Rate; D006801:Humans; D016130:Immunophenotyping; D007200:Indican / Q000097:blood / Q000378:metabolism* / Q000652:urine; D008264:Macrophages / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*; D010641:Phenotype; D017382:Reactive Oxygen Species / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D000098902:CD163 Antigen; D017382:Reactive Oxygen Species; D018336:Receptors, Aryl Hydrocarbon; D011956:Receptors, Cell Surface; D007200:Indican