Pieper Galen M, Olds Cara L, Bub Jeffrey D, Lindholm Paul F
Division of Transplant Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee 53226, USA.
Am J Physiol Heart Circ Physiol. 2002 Dec;283(6):H2315-21. doi: 10.1152/ajpheart.00469.2002.
Human immunodeficiency virus (HIV)-1 Tat released from HIV-1-infected monocytes is believed to enter other cells via an integrin-facilitated pathway, resulting in altered gene expression. Indeed, exogenous Tat protein can increase cell adhesion molecule gene expression in human endothelial cells. Signaling pathways initiated by Tat in endothelial cells are not known. We evaluated the ability of endogenous tat to stimulate monocyte adhesion via activation of nuclear factor-kappaB (NF-kappaB) within human umbilical vein endothelial cells. Transfection with pcTat, but not control vector DNA, increased NF-kappaB binding activity, NF-kappaB luciferase reporter activity, and monocyte adhesion. pcTat also increased kappaB-dependent HIV-1-LTR-CAT reporter activity 28-fold compared with a 3-fold increase produced by transfection with an equivalent amount of pcTax (from human leukemia virus). The pcTat-induced increase in pNF-kappaB-Luc activity and monocyte adhesion to endothelial cells was blocked by cotransfection with dominant-negative mutant IkappaBalpha and by incubation with 10 mM aspirin. We conclude that monocyte adhesion to human endothelial cells stimulated by pcTat is mediated via an NF-kappaB-dependent mechanism. Furthermore, inhibition studies using aspirin suggest that pcTat-stimulated NF-kappaB activation and monocyte adhesion occur via a redox-sensitive mechanism.
据信，从感染了人类免疫缺陷病毒1型（HIV-1）的单核细胞释放出的HIV-1反式激活因子（Tat），会通过整合素介导的途径进入其他细胞，从而导致基因表达改变。实际上，外源性Tat蛋白可增加人内皮细胞中细胞黏附分子的基因表达。Tat在内皮细胞中启动的信号通路尚不清楚。我们评估了内源性tat通过激活人脐静脉内皮细胞中的核因子-κB（NF-κB）来刺激单核细胞黏附的能力。用pcTat转染而非对照载体DNA转染，可增加NF-κB结合活性、NF-κB荧光素酶报告基因活性以及单核细胞黏附。与等量pcTax（来自人类白血病病毒）转染产生的3倍增加相比，pcTat还使κB依赖性HIV-1长末端重复序列-氯霉素乙酰转移酶（HIV-1-LTR-CAT）报告基因活性增加了28倍。pcTat诱导的pNF-κB-Luc活性增加以及单核细胞与内皮细胞的黏附，被与显性负性突变体IκBα共转染以及与10 mM阿司匹林孵育所阻断。我们得出结论，pcTat刺激的单核细胞与人类内皮细胞的黏附是通过NF-κB依赖性机制介导的。此外，使用阿司匹林的抑制研究表明，pcTat刺激的NF-κB激活和单核细胞黏附是通过氧化还原敏感机制发生的。
