title: 1,25-dihydroxyvitamin D3 downregulates aromatase expression and inflammatory cytokines in human macrophages.
abstract: OBJECTIVE
  Vitamin D deficiency seems to be involved in the development and severity of autoimmune/inflammatory diseases such as rheumatoid arthritis (RA). To evaluate the influence of calcitriol (1,25-dihydroxyvitamin D3, 1,25(OH)2D3) on aromatase expression in cultures of human macrophages, as a new target for vitamin D cell modulation and pro-inflammatory cytokine production.
  
  
  METHODS
  Cultures of human monocytic THP-1 cells were activated to macrophages and treated for 24 hours with 1,25(OH)2D3 (10-8M), 17β-estradiol (E2, 10-8M) both alone and in combination, in order to evaluate the effects on the intracrine estrogen metabolism. Untreated human macrophages were used as controls (basal). P450-aromatase synthesis was evaluated by immunocytochemistry (ICC) and western blot analysis (WB). The expression of P450-aromatase gene (CYP19A1) was investigated by real-time PCR (RT-PCR). Macrophage pro-inflammatory cytokines IL1-β, IL-6 and TNF-α were evaluated by ELISA and WB.
  
  
  RESULTS
  In E2 untreated condition, 1,25(OH)2D3 reduced P450-aromatase synthesis and CYP19A1 gene expression in cultured cells. Moreover, pro-inflammatory cytokine production (IL1-β, IL-6 and TNF-α) was significantly reduced by 1,25(OH)2D3 treatment (p<0.001 vs. basal for all cytokines). However, 1,25(OH)2D3 was found to significantly downregulate the E2-mediated increase in P450-aromatase synthesis and gene expression (p<0.001 for both vs. E2-treated macrophages), as well as the production of all pro-inflammatory cytokines (p<0.001 vs. E2-treated cells).
  
  
  CONCLUSIONS
  Our data suggest that 1,25(OH)2D3 may downregulate the pro-inflammatory cytokine production in human activated macrophages by significantly decreasing the aromatase activity, especially in presence of an estrogenic milieu such as in the RA synovial tissue.
authors.affiliation: Research Laboratory of Nephrology, Department of Internal Medicine, University of Genova, Genova, Italy. villaggiob@unige.it
authors.forename: Barbara
authors.initials: B
authors.lastname: Villaggio
authors.forename: Stefano
authors.initials: S
authors.lastname: Soldano
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cutolo
mesh_terms: D001141:Aromatase / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002117:Calcitriol / Q000494:pharmacology*; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism*; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry; D018836:Inflammation Mediators / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; C508600:IL6 protein, human; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D004958:Estradiol; D001141:Aromatase; C561410:CYP19A1 protein, human; D002117:Calcitriol