title: Secretory phospholipases A2 induce cytokine release from blood and synovial fluid monocytes.
abstract: Secretory phospholipases A2 (sPLA2) are released in the blood of patients with various inflammatory diseases and exert proinflammatory activities by releasing arachidonic acid (AA), the precursor of eicosanoids. We examined the ability of four sPLA2 to activate blood and synovial fluid monocytes in vitro. Monocytes were purified from blood of healthy donors or from synovial fluid of patients with rheumatoid arthritis by negative immunoselection and by adherence to plastic dishes, respectively. The cells were incubated with group IA, IB, IIA and III sPLA2 and the release of TNF-alpha, IL-6 and IL-12 was determined by ELISA. Group IA, IB and IIA sPLA2 induced a concentration-dependent release of TNF-alpha and IL-6 from blood monocytes. These sPLA2 activated IL-12 production only in monocytes preincubated with IFN-gamma. Group IA and IIA sPLA2 also induced TNF-alpha and IL-6 release from synovial fluid monocytes. TNF-alpha and IL-6 release paralleled an increase in their mRNA expression and was independent from the capacity of sPLA2 to mobilize AA. These results indicate that sPLA2 stimulate cytokine release from blood and synovial fluid monocytes by a mechanism at least partially unrelated to their enzymatic activity. This effect may concur with the generation of AA in the proinflammatory activity of sPLA2 released during inflammatory diseases.
authors.affiliation: Division of Clinical Immunology and Allergy, University of Naples Federico II, Naples, Italy. triggian@unina.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Triggiani
authors.forename: Francescopaolo
authors.initials: F
authors.lastname: Granata
authors.forename: Alfonso
authors.initials: A
authors.lastname: Oriente
authors.forename: Marco
authors.initials: M
authors.lastname: Gentile
authors.forename: Angelica
authors.initials: A
authors.lastname: Petraroli
authors.forename: Barbara
authors.initials: B
authors.lastname: Balestrieri
authors.forename: Gianni
authors.initials: G
authors.lastname: Marone
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D002478:Cells, Cultured; D054501:Group II Phospholipases A2; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis*; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D009000:Monocytes / Q000166:cytology / Q000187:drug effects*; D010741:Phospholipases A / Q000378:metabolism / Q000494:pharmacology*; D012333:RNA, Messenger; D013582:Synovial Fluid / Q000166:cytology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D016718:Arachidonic Acid; D010741:Phospholipases A; D054501:Group II Phospholipases A2