Selective inhibition of cytosolic phospholipase A(2) in activated human monocytes - Regulation of superoxide anion production and low density lipoprotein oxidation
Selective inhibition of cytosolic phospholipase A(2) in activated human monocytes - Regulation of superoxide anion production and low density lipoprotein oxidation
复制标题
DOI：
10.1074/jbc.272.4.2404
复制
发表时间：
1997-01-24
影响因子：
4.8
通讯作者：
Cathcart, MK
中科院分区：
文献类型：
--
作者：
Li, Q;Cathcart, MK
我们以前的研究表明，单核细胞介导的低密度脂蛋白(LDL)脂质氧化需要单核细胞激活和释放O-2(自由基阴离子)。我们还发现，在这个潜在的致病过程中，细胞内钙水平和蛋白激酶C活性是必不可少的参与者。在这些研究中，我们进一步研究了激活的人单核细胞氧化低密度脂蛋白的机制，特别是胞浆磷脂酶A(2)(CPLA(2))信号通路的潜在作用。研究最充分的CPLA(2)，其分子质量为85 kDa，已报道受钙离子和磷酸化的调节。我们发现，CPLA(2)的蛋白水平和CPLA(2)的酶活性仅在酵母多糖激活人单核细胞时被诱导，而被报道为CPLA(2)的特异性抑制剂AA-COOF3对CPLA(2)活性的药理抑制作用，导致激活的人单核细胞对CPLA(2)酶活性和低密度脂蛋白氧化的抑制作用呈剂量依赖关系，而SLA(2)活性不受影响。为了证实这些发现，我们使用了特定的反义寡核苷酸来抑制CPLA(2)。我们观察到，反义寡核苷酸处理导致CPLA(2)蛋白表达和酶活性的抑制，以及单核细胞介导的低密度脂蛋白氧化。此外，反义寡核苷酸处理可显著抑制激活的人单核细胞产生O-2(自由基阴离子)。在平行实验组中，CPLA(2)正义寡核苷酸不影响CPLA(2)蛋白表达、CPLA(2)酶活性、O-2(自由基)的产生，也不影响单辛基介导的低密度脂蛋白(LDL)氧化。这些研究支持CPLA(2)活性是激活的单核细胞氧化低密度脂蛋白所必需的。
Our previous studies have shown that monocyte activation and release of O-2(radical anion) are required for monocyte-mediated low density lipoprotein (LDL) lipid oxidation. We have also found that intracellular Ca2+ levels and protein kinase C activity are requisite participants in this potentially pathogenic process. In these studies, we further investigated the mechanisms involved in the oxidation of LDL lipids by activated human monocytes, particularly the potential contributions of the cytosolic phospholipase A(2) (cPLA(2)) signaling pathway. The most well-studied cPLA(2), has a molecular mass of 85 kDa and has been reported to be regulated by both Ca2+ and phosphorylation. We found that cPLA(2) protein levels and cPLA(2) enzymatic activity mere induced upon activation of human monocytes by opsonized zymosan, Pharmacologic inhibition of cPLA(2) activity by AA-COOF3, which has been reported to be a specific inhibitor of cPLA(2) as compared with sPLA(2), caused a dose-dependent inhibition of cPLA(2) enzymatic activity and LDL lipid oxidation by activated human monocytes, whereas sPLA(2) activity was not affected. To corroborate these findings, we used specific antisense oligonucleotides to inhibit cPLA(2). We observed that treatment with antisense oligonucleotides caused suppression of both cPLA(2) protein expression and enzymatic activity as well as monocyte-mediated LDL lipid oxidation. Furthermore, antisense oligonucleotide treatment caused a substantial inhibition of O-2(radicl anion) production by activated human monocytes. In parallel experimental groups, cPLA(2) sense oligonucleotides did not affect cPLA(2) protein expression, cPLA(2) enzymatic activity, O-2(radical anion) production, or monoctye-mediated LDL Lipid oxidation. These studies support the proposal that cPLA(2) activity is required for activated monocytes to oxidize LDL Lipids.