Chenevier-Gobeaux Camille, Simonneau Catherine, Therond Patrice, Bonnefont-Rousselot Dominique, Poiraudeau Serge, Ekindjian Ohvanesse G, Borderie Didier
Laboratoire de Biochimie A, Hôpital Cochin, Assistance Publique - Hôpitaux de Paris (AP-HP), 27 rue du Faubourg Saint-Jacques, 75679 Paris cedex 14, France.
Life Sci. 2007 Sep 8;81(13):1050-8. doi: 10.1016/j.lfs.2007.08.018. Epub 2007 Aug 25.
NADPH oxidase Nox2 is involved in the production of superoxide by rheumatoid synovial cells, constitutively and after pro-inflammatory cytokine treatment. The aims of the study were to evaluate the capacity of these cells to produce the superoxide anion in response to arachidonic acid (AA), and to study the involvement of cytosolic phospholipase A(2) (cPLA(2)) in the cytokine regulation of Nox2. Superoxide production was quantified in synovial cells obtained from six patients with rheumatoid arthritis (RA) and six with osteoarthritis (OA), stimulated with (i) AA, and (ii) PLA(2) inhibitors prior to IL-1beta or TNF-alpha treatment. Total cellular AA concentrations and PLA(2) activity were measured; effects of cytokines and NADPH oxidase inhibitors on the AA-activatable proton channel opening were also studied. Our results demonstrated that AA enhanced superoxide production in RA and OA cells; this production was significantly inhibited by iodonium diphenyl and apocynin. cPLA(2) inhibitors inhibited both IL-1beta and TNF-alpha-induced superoxide production in RA and OA cells. Basal PLA(2) activity was significantly more important in RA cells than in OA cells; PLA(2) activity was increased in IL-1beta and TNF-alpha pre-treated RA cells, and cPLA(2) inhibitors inhibited this activity. Opening of the AA-activatable proton channel was amplified when RA cells were pre-treated with both IL-1beta and TNF-alpha, and iodonium diphenyl and apocynin inhibited these cytokine effects. We concluded that AA is an important cofactor for synovial NADPH oxidase activity. Despite their direct effects on p47-phox phosphorylation, cytokines can also regulate the Nox2 activity though the AA-activatable associated H(+) channel.
NADPH氧化酶Nox2参与类风湿性滑膜细胞组成性以及促炎细胞因子处理后超氧化物的产生。本研究的目的是评估这些细胞对花生四烯酸（AA）产生超氧阴离子的能力，并研究胞质磷脂酶A2（cPLA2）在细胞因子对Nox2的调节中的作用。对从6例类风湿性关节炎（RA）患者和6例骨关节炎（OA）患者获取的滑膜细胞进行超氧化物产生的定量分析，这些细胞用（i）AA，以及（ii）在IL-1β或TNF-α处理之前用PLA2抑制剂进行刺激。测量细胞总的AA浓度和PLA2活性；还研究了细胞因子和NADPH氧化酶抑制剂对AA可激活的质子通道开放的影响。我们的结果表明，AA增强了RA和OA细胞中超氧化物的产生；这种产生被二苯基碘鎓和夹竹桃麻素显著抑制。cPLA2抑制剂抑制RA和OA细胞中IL-1β和TNF-α诱导的超氧化物产生。基础PLA2活性在RA细胞中比在OA细胞中显著更重要；在IL-1β和TNF-α预处理的RA细胞中PLA2活性增加，并且cPLA2抑制剂抑制这种活性。当RA细胞用IL-1β和TNF-α两者预处理时，AA可激活的质子通道的开放被放大，并且二苯基碘鎓和夹竹桃麻素抑制这些细胞因子的作用。我们得出结论，AA是滑膜NADPH氧化酶活性的重要辅助因子。尽管细胞因子对p47-吞噬细胞氧化酶磷酸化有直接作用，但它们也可以通过AA可激活的相关H+通道调节Nox2活性。
