Kaur Jaswinder, Woodman Richard C, Kubes Paul
Immunology Research Group, Department of Physiology, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
Am J Physiol Heart Circ Physiol. 2003 Apr;284(4):H1095-103. doi: 10.1152/ajpheart.00016.2002. Epub 2002 Dec 27.
Thrombin-stimulated endothelium synthesizes numerous adhesion molecules to recruit leukocytes; however, it is unknown which intracellular pathways are responsible for this event. A recent report from our laboratory has shown that thrombin induces E-selectin expression and that blocking nuclear factor-kappa B (NF-kappa B) activity partially blocked both E-selectin expression (60%) and leukocyte recruitment. In this study, we systematically assessed the importance of p38 MAPK in thrombin-induced NF-kappa B activation and E-selectin-dependent leukocyte recruitment. Thrombin caused phosphorylation of p38 MAPK, its substrate ATF-2, and JNK MAPK, but not ERK MAPK. The p38 MAPK inhibitors, SKF86002 and SB-203580 only reduced ATF-2 activity. We treated human umbilical vein endothelial cells with SKF86002, 1 h before thrombin stimulation, and noted inhibition of NF-kappa B mobilization and complete inhibition of leukocyte rolling and adhesion in a laminar flow chamber. Significant inhibition of leukocyte recruitment and E-selectin expression was also observed with SB-203580. SKF86002 did not affect other systems, including tumor necrosis factor-alpha-induced E-selectin-dependent leukocyte recruitment. Moreover, thrombin-induced rapid mobilization of P-selectin from Weibel Palade bodies was not p38 MAPK dependent. These data suggest that thrombin induces p38 MAPK activation, which leads to NF-kappa B mobilization to the nucleus and causes the upregulation of E-selectin and subsequent leukocyte recruitment.
凝血酶刺激的内皮细胞合成多种黏附分子以募集白细胞;然而,尚不清楚哪些细胞内途径参与了这一过程。我们实验室最近的一份报告显示,凝血酶可诱导E-选择素表达,而阻断核因子-κB(NF-κB)活性可部分阻断E-选择素表达(60%)和白细胞募集。在本研究中,我们系统评估了p38丝裂原活化蛋白激酶(p38 MAPK)在凝血酶诱导的NF-κB激活及E-选择素依赖的白细胞募集中的重要性。凝血酶可导致p38 MAPK、其底物活化转录因子2(ATF-2)及应激活化蛋白激酶(JNK MAPK)磷酸化,但不会使细胞外信号调节激酶(ERK MAPK)磷酸化。p38 MAPK抑制剂SKF86002和SB-203580仅降低了ATF-2活性。我们在凝血酶刺激前1小时用SKF86002处理人脐静脉内皮细胞,并观察到在层流室中NF-κB动员受到抑制,白细胞滚动和黏附完全被抑制。使用SB-203580也观察到白细胞募集和E-选择素表达受到显著抑制。SKF86002不影响其他系统,包括肿瘤坏死因子-α诱导的E-选择素依赖的白细胞募集。此外,凝血酶诱导的P-选择素从魏尔-帕拉德小体的快速动员不依赖于p38 MAPK。这些数据表明,凝血酶诱导p38 MAPK激活,进而导致NF-κB向细胞核动员,引起E-选择素上调及随后的白细胞募集。