Shiner Maayan, Fuhrman Bianca, Aviram Michael
Lipid Research Laboratory, Technion Faculty of Medicine, The Rappaport Family Institute for Research in the Medical Sciences and Rambam Medical Center, Haifa 31096, Israel.
Free Radic Biol Med. 2004 Dec 15;37(12):2052-63. doi: 10.1016/j.freeradbiomed.2004.09.003.
Paraoxonase 2 (PON2) is a member of the paraoxonases gene family. PON2 is ubiquitously present in cells, including macrophages, and it was shown to protect against cellular oxidative stress. The aim of the present study was to analyze mechanisms involved in PON2 expression during monocyte/macrophage differentiation. PON2 expression was analyzed in vitro in THP-1 cells differentiated with 1alpha,25-dihydroxyvitamin D3 and in vivo in mouse peritoneal macrophages (MPM) isolated at increasing time intervals after intraperitoneal thioglycollate injection. PON2 expression (mRNA and protein) and activity gradually increased during monocyte/macrophage differentiation, up to five fold and eight fold in vitro and in vivo, respectively. This effect was associated with a gradual increase in cellular superoxide anion production. Supplementation of vitamin E to Balb/C mice inhibited the reduced nicotinamide adenine dinuleotide phosphate (NADPH)-oxidase-dependent increase in cellular superoxide anion production by 50% and down-regulated PON2 mRNA expression and activity by 30 and 60%, respectively. Furthermore, PON2 expression was lower by nine fold in MPM isolated from P47(phox-/-) (inactive NADPH oxidase) mice, in comparison to MPM from control mice. PON2 expression was found to be regulated, at least in part, by the transcription factor AP-1, as suggested by decreased JDP2 (AP-1 repressor) protein expression in the nucleus and by decreased PON2 expression in the presence of a Jun N-terminal kinase inhibitor (SP600125). The present study demonstrates, for the first time, that PON2 expression increases in monocytes during their maturation into macrophage as a result of NADPH-oxidase activation, and this process is partly regulated by the transcription factor AP-1. PON2 stimulation may represent a compensatory mechanism against the increase in cellular superoxide anion production and atherogenesis.
对氧磷酶2（PON2）是对氧磷酶基因家族的成员之一。PON2普遍存在于包括巨噬细胞在内的细胞中，并且已证明它能抵御细胞氧化应激。本研究的目的是分析单核细胞/巨噬细胞分化过程中参与PON2表达的机制。在体外，用1α,25 - 二羟基维生素D3诱导分化的THP - 1细胞中分析PON2表达；在体内，分析腹腔注射巯基乙酸盐后不同时间间隔分离得到的小鼠腹腔巨噬细胞（MPM）中的PON2表达。在单核细胞/巨噬细胞分化过程中，PON2表达（mRNA和蛋白质）及活性逐渐增加，在体外和体内分别增加至五倍和八倍。这种效应与细胞超氧阴离子生成的逐渐增加相关。给Balb/C小鼠补充维生素E可使还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶依赖性的细胞超氧阴离子生成增加抑制50%，并分别使PON2 mRNA表达和活性下调30%和60%。此外，与对照小鼠的MPM相比，从P47(phox-/-)（无活性NADPH氧化酶）小鼠分离得到的MPM中PON2表达低九倍。如细胞核中JDP2（AP - 1阻遏物）蛋白表达降低以及在存在Jun N末端激酶抑制剂（SP600125）时PON2表达降低所表明的，发现PON2表达至少部分受转录因子AP - 1调控。本研究首次证明，由于NADPH氧化酶激活，单核细胞在成熟为巨噬细胞的过程中PON2表达增加，并且这一过程部分受转录因子AP - 1调控。PON2刺激可能代表一种针对细胞超氧阴离子生成增加和动脉粥样硬化的代偿机制。
