Nakao J, Koshihara Y, Ito H, Murota S, Chang W C
Life Sci. 1985 Oct 14;37(15):1435-42. doi: 10.1016/0024-3205(85)90083-9.
Platelet-derived growth factor (PDGF) has a chemotactic effect on smooth muscle cells, which is inhibited by lipoxygenase inhibitor caffeic acid. In order to study the role of endogenous lipoxygenase products of arachidonic acid on the chemotactic action of PDGF, effects of PDGF on the lipoxygenase pathway in smooth muscle cells were examined. Lipoxygenase products were analyzed by high-performance liquid chromatography. 15-, 5- and 12-lipoxygenase activities, in order of magnitude, were found in smooth muscle cell homogenate. However, when the lipoxygenase products were analyzed using intact cells prelabelled with [14C]arachidonic acid, only 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid (HETE) was found to be produced endogenously. In addition, 12-HETE was not released into the medium. Treatment of the cells with PDGF increased the endogenous production of 12-HETE. The amounts of intracellular 12-HETE in PDGF-treated cells were 126, 132 and 146% at 1, 3, and 10 hr's after the initiation of PDGF treatment, respectively, when control value at each time point was considered as 100%. Caffeic acid (10(-4) M) completely inhibited the PDGF effect on 12-HETE production. However, PDGF treatment did not significantly alter the 12-lipoxygenase activity. These results suggest that the stimulatory effect of PDGF on 12-HETE production was not mediated by the activation of 12-lipoxygenase activity. Since 12-HETE itself is a potent chemoattractant for smooth muscle cells, the present dat strongly suggest that 12-HETE could be an important intracellular mediator of the chemotactic action of PDGF on aortic smooth muscle cells.
血小板衍生生长因子（PDGF）对平滑肌细胞具有趋化作用，而脂氧合酶抑制剂咖啡酸可抑制这种作用。为了研究花生四烯酸的内源性脂氧合酶产物在PDGF趋化作用中的作用，研究了PDGF对平滑肌细胞脂氧合酶途径的影响。通过高效液相色谱分析脂氧合酶产物。在平滑肌细胞匀浆中发现了15-、5-和12-脂氧合酶活性，活性大小依次排列。然而，当使用预先用[14C]花生四烯酸标记的完整细胞分析脂氧合酶产物时，发现仅内源性产生12-L-羟基-5,8,10,14-二十碳四烯酸（HETE）。此外，12-HETE未释放到培养基中。用PDGF处理细胞可增加12-HETE的内源性产生。当将每个时间点的对照值视为100%时，在PDGF处理开始后1、3和10小时，PDGF处理细胞中细胞内12-HETE的量分别为126%、132%和146%。咖啡酸（10^(-4) M）完全抑制了PDGF对12-HETE产生的作用。然而，PDGF处理并未显著改变12-脂氧合酶活性。这些结果表明，PDGF对12-HETE产生的刺激作用不是由12-脂氧合酶活性的激活介导的。由于12-HETE本身是平滑肌细胞的一种有效的趋化剂，目前的数据强烈表明，12-HETE可能是PDGF对主动脉平滑肌细胞趋化作用的重要细胞内介质。
