Bokhari Sirosh M, Zhou Lisa, Karasek Marvin A, Paturi Sarita G, Chaudhuri Vaishali
Program in Epithelial Biology, Department of Dermatology, Stanford University School of Medicine, Stanford, California 94305, USA.
J Invest Dermatol. 2006 Feb;126(2):460-7. doi: 10.1038/sj.jid.5700071.
Activation of protein kinase C (PKC) induces phenotypic changes in the morphology of microvascular endothelial cells that affect major functions of the microvasculature. These functions include the first stages of sprouting in angiogenesis, cell migration following wounding, and vascular permeability. The specific isoform(s) of PKC responsible for each of these changes has not been previously identified. In this study, we used two inflammatory agents, IL-1beta and phorbol myristic acetate, to activate PKC isozymes and specific inhibitors of PKCalpha (Gö6976) and PKCbeta (hispidin) to distinguish how each of these isoform(s) controls angiogenesis, wound healing, and permeability. In all cases, only inhibition of PKCalpha inhibited each of these functions when compared to the inhibition of PKCbeta. Additional analysis of the mechanism of action of Gö6976 (RT-PCR, Western blots, and immunohistochemistry) of the changes in the phosphorylated and nonphosphorylated forms of PKCalpha in the cell membrane and cytoplasm confirmed the specificity of PKCalpha inhibition by Gö6976. These studies therefore indicate a specific and a regulatory role of the PKCalpha isoform in three major endothelial cell functions that are important in the maintenance of microvascular homeostasis.
蛋白激酶C（PKC）的激活会诱导微血管内皮细胞形态发生表型变化，从而影响微血管的主要功能。这些功能包括血管生成中萌芽的初始阶段、伤口愈合后的细胞迁移以及血管通透性。此前尚未确定负责这些变化的PKC的具体同工型。在本研究中，我们使用两种炎症因子白细胞介素-1β（IL-1β）和佛波醇肉豆蔻酸酯来激活PKC同工酶，并使用PKCα特异性抑制剂（Gö6976）和PKCβ特异性抑制剂（组蛋白）来区分这些同工型如何控制血管生成、伤口愈合和通透性。在所有情况下，与抑制PKCβ相比，只有抑制PKCα才能抑制所有这些功能。对Gö6976作用机制的进一步分析（逆转录聚合酶链反应、蛋白质免疫印迹和免疫组织化学），针对细胞膜和细胞质中PKCα磷酸化和非磷酸化形式的变化，证实了Gö6976对PKCα抑制的特异性。因此，这些研究表明PKCα同工型在维持微血管稳态至关重要的三种主要内皮细胞功能中具有特定的调节作用。
