Zhu P, Xiong W, Rodgers G, Qwarnstrom E E
Department of Pathology, University of Washington, Seattle, WA 98195-7470, USA.
Biochem J. 1998 Mar 1;330 ( Pt 2)(Pt 2):975-81. doi: 10.1042/bj3300975.
Interleukin 1 (IL-1)-mediated gene regulation is dependent on cell-matrix interactions. Both IL-1-activated pathways, nuclear factor kappaB (NF-kappaB) and the stress-activated protein kinase (SAPK), can be regulated by cell adhesion and changes in the cytoskeleton, suggesting that cell-matrix effects on IL-1 responses are initiated in part though effects on signal transduction. Here we show that IL-1-induced transient alterations in cell shape and in the cytoskeleton in fibronectin attached cells are correlated with effects on peak activity of NF-kappaB and SAPK. Cells on fibronectin showed a 1.5-2-fold enhancement in IL-1-induced NF-kappaB activity compared with levels in cells on poly(l-lysine) or bare tissue culture plates. The effect was increased with increasing concentrations of fibronectin and was most prominent at lower concentrations of IL-1. In contrast, fibronectin attachment caused an approx. 50% decrease in the IL-1 activation of SAPK, eliminating the peak activity after 15 min of stimulation with IL-1. IL-1-induced NF-kappaB activity showed a successive, substratum-independent increase during 4 h of attachment and spreading, whereas the inhibitory effect of fibronectin on the SAPK pathway was induced at the initial stages of attachment. Further, the addition of a peptide containing the motif RGD resulted in a 40% decrease in NF-kappaB activity in cells on fibronectin, largely accounted for by an effect on the p50/p65 heterodimer. Similarly, blocking of integrin aggregation by RGD-containing peptide resulted in a total abrogation of the fibronectin effect on IL-1-induced SAPK activity. The results demonstrate disparate effects of cell adhesion on the activation by IL-1 of the NF-kappaB and SAPK pathways. Thus fibronectin attachment causes an up-regulation of NF-kappaB activity in the presence of IL-1, whereas in contrast it results in a pronounced decrease in IL-1-induced SAPK activity.
白细胞介素1（IL-1）介导的基因调控依赖于细胞与基质的相互作用。IL-1激活的两条途径，即核因子κB（NF-κB）和应激激活蛋白激酶（SAPK），均可受到细胞黏附及细胞骨架变化的调节，这表明细胞与基质对IL-1反应的影响部分是通过对信号转导的作用而起始的。在此我们表明，IL-1诱导的纤连蛋白附着细胞的细胞形状及细胞骨架的瞬时改变与对NF-κB和SAPK峰值活性的影响相关。与聚（L-赖氨酸）包被的细胞或裸组织培养板上的细胞相比，纤连蛋白上的细胞在IL-1诱导的NF-κB活性方面表现出1.5至2倍的增强。随着纤连蛋白浓度的增加，这种效应增强，且在较低浓度的IL-1时最为显著。相反，纤连蛋白附着导致SAPK的IL-1激活降低约50%，在用IL-1刺激15分钟后消除了峰值活性。IL-1诱导的NF-κB活性在附着和铺展的4小时内呈现出连续的、不依赖于基质的增加，而纤连蛋白对SAPK途径的抑制作用在附着的初始阶段就被诱导。此外，添加含有基序RGD的肽导致纤连蛋白上细胞的NF-κB活性降低40%，这在很大程度上是由对p50/p65异二聚体的作用所致。同样，用含RGD的肽阻断整合素聚集导致纤连蛋白对IL-1诱导的SAPK活性的作用完全消除。结果表明细胞黏附对IL-1激活NF-κB和SAPK途径具有不同的影响。因此，在存在IL-1的情况下，纤连蛋白附着导致NF-κB活性上调，而相反，它导致IL-1诱导的SAPK活性显著降低。
