Kacimi R, Karliner J S, Koudssi F, Long C S
Veterans Affairs Medical Center, the Cardiovascular Research Institute, and the Department of Medicine, University of California, San Francisco 94121, USA.
Circ Res. 1998 Mar 23;82(5):576-86. doi: 10.1161/01.res.82.5.576.
Adhesion molecules mediate inflammatory myocardial injury after ischemia/reperfusion. Cytokine release and hypoxia are features of acute ischemia that may influence expression of these molecules. Accordingly, we studied intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) responses to cytokines and acute hypoxia in cultured myocardial cells. Northern blot analysis and immunoassay showed that the proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha stimulated concentration-dependent increases in ICAM and VCAM mRNA and protein. In both cardiac myocytes and fibroblasts, pretreatment with a specific inhibitor of nuclear transcription factor-kappaB (NF-kappaB) prevented cytokine induction of both molecules. We also found that inhibition of tyrosine kinase and p38/RK (stress-activated protein kinase) pathways prevented IL-1beta-induced ICAM and VCAM protein synthesis, whereas extracellular signal-regulated protein kinase (ERK1/ERK2) inhibition did not. Neither hypoxia (0% O2 for 6 hours) alone nor hypoxia/reoxygenation had any significant effect on ICAM and VCAM mRNA. However, hypoxia did enhance IL-1beta-induced ICAM mRNA expression in myocytes. As a possible mechanism of this synergistic action on CAM expression, hypoxia induced a time-dependent increase in the DNA binding activity of both NF-kappaB and activator protein-1 (AP-1), two transcription factors important for cell adhesion molecule expression. In contrast to the enhanced ICAM mRNA induced by IL-1beta during hypoxia, however, protein levels for this adhesion molecule were unchanged beyond IL-1beta-stimulated levels, suggesting posttranscriptional and/or posttranslational control mechanisms. We conclude that cytokines regulate ICAM and VCAM mRNA and protein in both cardiac myocytes and fibroblasts. Furthermore, adhesion molecule induction requires translocation of at least two transcription factors, NF-kappaB and AP-1.
黏附分子介导缺血/再灌注后的炎症性心肌损伤。细胞因子释放和缺氧是急性缺血的特征，可能影响这些分子的表达。因此，我们研究了培养心肌细胞中细胞间黏附分子（ICAM）和血管细胞黏附分子（VCAM）对细胞因子和急性缺氧的反应。Northern印迹分析和免疫测定表明，促炎细胞因子白细胞介素-1β（IL-1β）和肿瘤坏死因子-α刺激ICAM和VCAM mRNA及蛋白浓度依赖性增加。在心肌细胞和成纤维细胞中，用核转录因子-κB（NF-κB）的特异性抑制剂预处理可阻止细胞因子对这两种分子的诱导。我们还发现，抑制酪氨酸激酶和p38/RK（应激激活蛋白激酶）途径可阻止IL-1β诱导的ICAM和VCAM蛋白合成，而抑制细胞外信号调节蛋白激酶（ERK1/ERK2）则无此作用。单独缺氧（6小时0%氧气）或缺氧/复氧对ICAM和VCAM mRNA均无显著影响。然而，缺氧确实增强了IL-1β诱导的心肌细胞中ICAM mRNA表达。作为这种对细胞黏附分子（CAM）表达协同作用的一种可能机制，缺氧诱导了NF-κB和激活蛋白-1（AP-1）这两种对细胞黏附分子表达重要的转录因子的DNA结合活性随时间依赖性增加。然而，与缺氧期间IL-1β诱导的ICAM mRNA增强相反，该黏附分子的蛋白水平在超过IL-1β刺激水平后并未改变，提示存在转录后和/或翻译后控制机制。我们得出结论，细胞因子调节心肌细胞和成纤维细胞中ICAM和VCAM的mRNA及蛋白。此外，黏附分子的诱导需要至少两种转录因子NF-κB和AP-1的易位。
