Weston M C, Collins M E, Cunningham F M
Department of Veterinary Basic Sciences and Pathology and Infectious Diseases, The Royal Veterinary College, Hertfordshire, UK.
J Vet Pharmacol Ther. 2008 Feb;31(1):31-8. doi: 10.1111/j.1365-2885.2007.00922.x.
Inappropriately activated eosinophils can contribute to disease pathogenesis and intracellular signalling pathways that regulate functional responses may represent a therapeutic target. Little is known about intracellular signalling in equine eosinophils and this study examined the role of phospholipase C (PLC) and a range of protein kinases on responses to histamine and CCL11. Histamine (10(-4) M) or CCL11 (5.6 x 10(-9) M)-induced actin polymerization, migration and superoxide production by eosinophils from healthy horses were compared in the presence and absence of selective kinase inhibitors. Inhibition of phosphatidylinositol-3 kinase (PI3K) significantly reduced the response in each assay. In contrast, whilst inhibition of PLC decreased actin polymerization and superoxide production, an increase in migration was observed; the latter effect was also seen when protein kinase C (PKC) was inhibited. With the exception of histamine-induced migration, which was significantly reduced by blocking extracellular regulated kinase (ERK)1/2, activation of ERK1/2, p38 MAPK and tyrosine kinase did not appear to play an important role in the responses studied. These results suggest that equine eosinophil activation by histamine and CCL11 is mediated through PI3K. Whilst PLC activation is required for actin polymerization and superoxide production, migration may be negatively regulated by PLC and PKC. These kinases represent potential targets for modulating eosinophil activation by multiple stimuli.
异常激活的嗜酸性粒细胞可促进疾病发病机制，而调节功能反应的细胞内信号通路可能是一个治疗靶点。关于马嗜酸性粒细胞的细胞内信号传导知之甚少，本研究探讨了磷脂酶C（PLC）和一系列蛋白激酶在对组胺和CCL11反应中的作用。在存在和不存在选择性激酶抑制剂的情况下，比较了组胺（10⁻⁴ M）或CCL11（5.6×10⁻⁹ M）诱导的健康马嗜酸性粒细胞的肌动蛋白聚合、迁移和超氧化物产生。磷脂酰肌醇-3激酶（PI3K）的抑制在每种检测中均显著降低反应。相比之下，虽然PLC的抑制降低了肌动蛋白聚合和超氧化物产生，但观察到迁移增加；当蛋白激酶C（PKC）被抑制时也出现了后一种效应。除了组胺诱导的迁移被细胞外调节激酶（ERK）1/2阻断而显著降低外，ERK1/2、p38丝裂原活化蛋白激酶（MAPK）和酪氨酸激酶的激活在研究的反应中似乎没有发挥重要作用。这些结果表明，组胺和CCL11对马嗜酸性粒细胞的激活是通过PI3K介导的。虽然肌动蛋白聚合和超氧化物产生需要PLC激活，但迁移可能受到PLC和PKC的负调节。这些激酶是调节多种刺激引起的嗜酸性粒细胞激活的潜在靶点。
