Wen Yeshao, Gu Jiali, Vandenhoff George E, Liu Xiaoping, Nadler Jerry L
Diabetes and Hormone Center, University of Virginia, Charlottesville, Virginia, USA.
Am J Physiol Heart Circ Physiol. 2008 Apr;294(4):H1933-8. doi: 10.1152/ajpheart.00260.2007. Epub 2008 Feb 22.
Monocyte chemoattractant protein (MCP)-1 plays a key role in atherosclerosis and inflammation associated with visceral adiposity by inducing mononuclear cell migration. Evidence shows that mouse peritoneal macrophages (MPM) express a 12-lipoxygenase (12/15-LO) that has been clearly linked to accelerated atherosclerosis in mouse models and increased monocyte endothelial interactions in both rodent and human cells. However, the role of 12/15-LO products in regulating MCP-1 expression in macrophages has not been clarified. In this study, we tested the role of 12/15-LO products using MPM and the mouse macrophage cell line, J774A.1 cells. We found that 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] increased MCP-1 mRNA and protein expression in J774A.1 cells and MPM. In contrast, 12(R)-HETE, a lipid not derived from 12/15-LO, did not affect MCP-1 expression. 15(S)-HETE also increased MCP-1 mRNA expression, but the effect was less compared with 12(S)-HETE. MCP-1 mRNA expression was upregulated in a macrophage cell line stably overexpressing 12/15-LO (Plox-86 cells) and in MPM isolated from a 12/15-LO transgenic mouse. In addition, the expression of MCP-1 was downregulated in MPM isolated from 12/15-LO knockout mice. 12(S)-HETE-induced MCP-1 mRNA expression was attenuated by specific inhibitors of protein kinase C (PKC) and p38 mitogen-activated protein kinase (p38). 12(S)-HETE also directly activated NADPH oxidase activity. Two NADPH oxidase inhibitors, apocynin and diphenyleneiodonium chloride, blocked 12(S)-HETE-induced MCP-1 mRNA. Apocynin attenuated 12(S)-HETE-induced MCP-1 protein secretion. These data show that 12(S)-HETE increases MCP-1 expression by inducing PKC, p38, and NADPH oxidase activity. These results suggest a potentially important mechanism linking 12/15-LO activation to MCP-1 expression that induces inflammatory cell infiltration.
单核细胞趋化蛋白（MCP）-1通过诱导单核细胞迁移，在与内脏肥胖相关的动脉粥样硬化和炎症中起关键作用。有证据表明，小鼠腹腔巨噬细胞（MPM）表达一种12-脂氧合酶（12/15-LO），在小鼠模型中该酶与动脉粥样硬化加速以及啮齿动物和人类细胞中单核细胞与内皮细胞的相互作用增加明显相关。然而，12/15-LO产物在调节巨噬细胞中MCP-1表达方面的作用尚未阐明。在本研究中，我们使用MPM和小鼠巨噬细胞系J774A.1细胞测试了12/15-LO产物的作用。我们发现12(S)-羟基二十碳四烯酸[12(S)-HETE]可增加J774A.1细胞和MPM中MCP-1的mRNA和蛋白表达。相比之下，12(R)-HETE（一种并非源自12/15-LO的脂质）不影响MCP-1表达。15(S)-HETE也可增加MCP-1的mRNA表达，但与12(S)-HETE相比作用较弱。在稳定过表达12/15-LO的巨噬细胞系（Plox-86细胞）以及从12/15-LO转基因小鼠分离的MPM中，MCP-1的mRNA表达上调。此外，从12/15-LO基因敲除小鼠分离的MPM中，MCP-1的表达下调。12(S)-HETE诱导的MCP-1 mRNA表达被蛋白激酶C（PKC）和p38丝裂原活化蛋白激酶（p38）的特异性抑制剂减弱。12(S)-HETE还直接激活NADPH氧化酶活性。两种NADPH氧化酶抑制剂，夹竹桃麻素和二苯基碘鎓氯化物，可阻断12(S)-HETE诱导的MCP-1 mRNA表达。夹竹桃麻素减弱了12(S)-HETE诱导的MCP-1蛋白分泌。这些数据表明，12(S)-HETE通过诱导PKC、p38和NADPH氧化酶活性增加MCP-1表达。这些结果提示了一种将12/15-LO激活与诱导炎症细胞浸润的MCP-1表达相联系的潜在重要机制。
