Kaul N, Gopalakrishna R, Gundimeda U, Choi J, Forman H J
Department of Molecular Pharmacology & Toxicology, University of Southern California, Los Angeles 90033, USA.
Arch Biochem Biophys. 1998 Feb 1;350(1):79-86. doi: 10.1006/abbi.1997.0487.
In macrophages, hydrogen peroxide appears to be a physiological activator of the transcription factor, nuclear factor kappa B (NF-kappa B); however, the molecular basis of H2O2-stimulated NF-kappa B activation is not well defined. The observations that NF-kappa B can be activated in cells by phorbol 12-myristate 13-acetate and in vitro by addition of protein kinase C (PKC) are suggestive of a role of PKC in NF-kappa B activation, which was investigated in the J774A.1 murine macrophage cell line. Basal NF-kappa B DNA-binding activity and nuclear localization were decreased by PKC inhibitors. Although PKC activity was modified by H2O2 with a similar time course as H2O2 activation of NF-kappa B, the H2O2-stimulated increase in NF-kappa B DNA binding and translocation to the nucleus was unaffected by PKC inhibitors. Furthermore, PKC down-regulation (through preincubation with phorbol esters) also affected only baseline NF-kappa B DNA binding but not H2O2-stimulated NF-kappa B activation. Buffering of changes in intracellular free calcium concentration also had no effect upon H2O2-stimulated NF-kappa B activation. Thus, classical PKC activity may modulate basal NF-kappa B activity but does not participate in H2O2-stimulated NF-kappa B activation.
在巨噬细胞中，过氧化氢似乎是转录因子核因子κB（NF-κB）的生理激活剂；然而，过氧化氢刺激NF-κB激活的分子基础尚未明确界定。有观察表明，佛波醇12-肉豆蔻酸酯13-乙酸酯可在细胞中激活NF-κB，体外添加蛋白激酶C（PKC）也可激活NF-κB，这提示PKC在NF-κB激活中发挥作用，本研究在J774A.1小鼠巨噬细胞系中对此进行了探究。PKC抑制剂可降低基础NF-κB DNA结合活性和核定位。尽管过氧化氢对PKC活性的修饰与过氧化氢激活NF-κB的时间进程相似，但PKC抑制剂并未影响过氧化氢刺激的NF-κB DNA结合增加以及向细胞核的转位。此外，PKC下调（通过与佛波醇酯预孵育）也仅影响基础NF-κB DNA结合，而不影响过氧化氢刺激的NF-κB激活。缓冲细胞内游离钙浓度的变化对过氧化氢刺激的NF-κB激活也没有影响。因此，经典PKC活性可能调节基础NF-κB活性，但不参与过氧化氢刺激的NF-κB激活。
