Helenius M, Kyrylenko S, Vehviläinen P, Salminen A
Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FIN-40351 Jyväskylä, Finland.
Antioxid Redox Signal. 2001 Feb;3(1):147-56. doi: 10.1089/152308601750100669.
Changes occur in gene expression during aging in vivo and in replicative senescence in vitro, suggesting that aging can affect gene regulation. We have recently observed age-related changes in ubiquitously expressed, oxidative stress-responsive nuclear factor-kappa B (NF-kappa B) pathway during aging. Here we report a significant age-related increase in nuclear NF-kappa B binding activity together with increased protein levels of p52 and p65 components in rat liver. An additional, higher molecular weight protein band seen in their western blots suggests that their post-translational modification (but not phosphorylation) occurs in liver, which might affect their nuclear localization and binding activity during aging. However, aging did not affect the protein levels of the main I kappa B inhibitors (I kappa B alpha and I kappa B beta) or I kappa B kinase (IKK)-complex subunits (IKK alpha, -beta, and -gamma) involved in NF-kappa B activation. In addition, the level of Ser32-phosphorylated I kappa B alpha was unaffected by age, suggesting that neither the IKK complex nor altered level of the main inhibitors is involved in the observed up-regulation of NF-kappa B binding activity. Furthermore, the expression of NF-kappa B mRNAs (p50, p52, p65, and c-rel) and the mRNAs of their inhibitors (I kappa B alpha and I kappa B beta) did not show any statistically significant age-related changes. These results indicate that the expression level of NF-kappa B genes is not significantly affected by aging. The up-regulation of constitutive nuclear NF-kappa B binding activity and increased levels of nuclear p52 and p65 proteins might affect the expression of some NF-kappa B target genes in the aging liver.
在体内衰老过程以及体外复制性衰老过程中，基因表达都会发生变化，这表明衰老会影响基因调控。我们最近观察到，在衰老过程中，普遍表达的、对氧化应激有反应的核因子κB（NF-κB）信号通路出现了与年龄相关的变化。在此，我们报告大鼠肝脏中核NF-κB结合活性随年龄显著增加，同时p52和p65成分的蛋白质水平也有所升高。在它们的蛋白质印迹中看到的另一条分子量更高的蛋白带表明，它们的翻译后修饰（而非磷酸化）发生在肝脏中，这可能会影响它们在衰老过程中的核定位和结合活性。然而，衰老并未影响参与NF-κB激活的主要IκB抑制剂（IκBα和IκBβ）或IκB激酶（IKK）复合物亚基（IKKα、-β和-γ）的蛋白质水平。此外，Ser32磷酸化的IκBα水平不受年龄影响，这表明IKK复合物以及主要抑制剂水平的改变均未参与观察到的NF-κB结合活性上调。此外，NF-κB mRNA（p50、p52、p65和c-rel）及其抑制剂（IκBα和IκBβ）的mRNA表达未显示出任何与年龄相关的统计学显著变化。这些结果表明，NF-κB基因的表达水平不受衰老的显著影响。组成型核NF-κB结合活性的上调以及核p52和p65蛋白水平的增加可能会影响衰老肝脏中一些NF-κB靶基因的表达。
