Zerfaoui Mourad, Suzuki Yasuhiro, Naura Amarjit S, Hans Chetan P, Nichols Charles, Boulares A Hamid
Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA, USA.
Cell Signal. 2008 Jan;20(1):186-94. doi: 10.1016/j.cellsig.2007.10.007. Epub 2007 Oct 12.
Although nuclear translocation of NF-kappaB and subsequent binding to promoters of ICAM-1 and VCAM-1 have been shown to be decisive for their expression, a number of discrepancies in the expression patterns of these adhesion molecules have been reported in both cell culture systems and disease settings, including atherosclerosis, asthma, and autoimmune diseases. Here we show that while p65 NF-kappaB nuclear translocation in TNF-treated smooth muscle cells (SMCs) was sufficient for the expression of VCAM-1, expression of ICAM-1 showed a critical requirement for PARP-1. I-kappaBalpha phosphorylation and subsequent degradation were virtually identical in both TNF-treated wild-type and PARP-1-/- SMCs. VCAM-1 expression in TNF-treated PARP-1-/- SMCs was completely inhibited by the NF-kappaB inhibitor, pyrrolidine dithiocarbamate, confirming that VCAM-1 expression was indeed NF-kappaB-dependent. The expression of both VCAM-1 and ICAM-1 was associated with a transient interaction between PARP-1 and p65 NF-kappaB when examined in the fibroblastic cell line, COS-7, and in the airway epithelial cell line, A549. Such interactions were confirmed using florescence resonance energy transfer analysis. Protein acetylation activity, mediated by p300/CBP, was required for both VCAM-1 and ICAM-1 expression in TNF-treated SMCs; however, the interaction of PARP-1 with p300/CBP was dispensable for VCAM-1 expression. These findings indicate that p65 NF-kappaB nuclear translocation may be sufficient for certain genes (e.g., VCAM-1) while insufficient for others (e.g., ICAM-1), thus providing a novel insight into the role of NF-kappaB in driving target gene expression. Furthermore, the data suggest a differential requirement for PARP-1 expression in inflammatory processes.
尽管已表明NF-κB的核转位以及随后与细胞间黏附分子-1（ICAM-1）和血管细胞黏附分子-1（VCAM-1）启动子的结合对它们的表达起决定性作用，但在细胞培养系统和疾病环境（包括动脉粥样硬化、哮喘和自身免疫性疾病）中，均报道了这些黏附分子表达模式存在一些差异。在此我们表明，虽然在肿瘤坏死因子（TNF）处理的平滑肌细胞（SMC）中p65 NF-κB核转位足以使VCAM-1表达，但ICAM-1的表达对聚（ADP-核糖）聚合酶-1（PARP-1）有严格需求。在TNF处理的野生型和PARP-1基因敲除的SMC中，I-κBα磷酸化及随后的降解实际上是相同的。TNF处理的PARP-1基因敲除的SMC中VCAM-1的表达被NF-κB抑制剂吡咯烷二硫代氨基甲酸盐完全抑制，证实VCAM-1的表达确实依赖于NF-κB。当在成纤维细胞系COS-7和气道上皮细胞系A549中检测时，VCAM-1和ICAM-1的表达均与PARP-1和p65 NF-κB之间的瞬时相互作用有关。使用荧光共振能量转移分析证实了这种相互作用。在TNF处理的SMC中，由p300/CBP介导的蛋白质乙酰化活性是VCAM-1和ICAM-1表达所必需的；然而，PARP-1与p300/CBP的相互作用对VCAM-1的表达并非必需。这些发现表明，p65 NF-κB核转位对某些基因（如VCAM-1）可能足够，但对其他基因（如ICAM-1）则不足，从而为NF-κB在驱动靶基因表达中的作用提供了新的见解。此外，数据表明在炎症过程中对PARP-1表达有不同需求。
