Laboratorio de Bioquímica, División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México, Ciudad de México, D.F., Mexico.
Toxicol In Vitro. 2010 Feb;24(1):319-26. doi: 10.1016/j.tiv.2009.08.007. Epub 2009 Aug 21.
Hydrogen peroxide (H(2)O(2)) increases protein tyrosine phosphorylation of numerous proteins in human gingival fibroblasts (HGFs). Two main proteins, with an apparent molecular weight of 44 and 42kDa, were phosphorylated after hydrogen peroxide stimulation of the human gingival fibroblasts. Further analysis identified these two proteins as ERK1/2. Maximum phosphorylation was detected at 10min post-H(2)O(2) treatment. Pretreatment with an MEK inhibitor, PD98059, inhibited H(2)O(2)-stimulated ERK1/2 phosphorylation in a dose-dependent manner. Treatment with H(2)O(2) also induced phosphorylation of protein kinase C-alpha (PKCalpha). Staurosporine, a PKC inhibitor, blocked ERK1/2 phosphorylation induced by H(2)O(2). In addition, H(2)O(2)-induced cell death was prevented by PD98059, SB203580, and calphostin C, which are MEK, p38 and PKC inhibitors, respectively. These results suggest that H(2)O(2) leads to the phosphorylation and activation of ERK1/2 in a PKC-dependent manner. These findings demonstrate that the MAPK signaling pathway plays an active role in mediating the H(2)O(2)-induced decrease in HGF cell viability and ATP depletion.
过氧化氢（H2O2）可增加人牙龈成纤维细胞（HGFs）中许多蛋白质的酪氨酸磷酸化。过氧化氢刺激人牙龈成纤维细胞后，有两种主要蛋白质（分子量分别为 44 和 42kDa）发生磷酸化。进一步分析鉴定这两种蛋白质为 ERK1/2。H2O2 处理后 10min 时可检测到最大磷酸化。用 MEK 抑制剂 PD98059 预处理可呈剂量依赖性抑制 H2O2 刺激的 ERK1/2 磷酸化。过氧化氢处理还诱导蛋白激酶 C-α（PKCalpha）磷酸化。PKC 抑制剂 staurosporine 可阻断 H2O2 诱导的 ERK1/2 磷酸化。此外，PD98059、SB203580 和 calphostin C（分别为 MEK、p38 和 PKC 抑制剂）可阻止 H2O2 诱导的细胞死亡。这些结果表明，H2O2 通过 PKC 依赖性方式导致 ERK1/2 的磷酸化和激活。这些发现表明 MAPK 信号通路在介导 H2O2 诱导的 HGF 细胞活力降低和 ATP 耗竭中发挥积极作用。
