Upadhyay Daya, Bundesmann Michael, Panduri Vijayalakshmi, Correa-Meyer Eduardo, Kamp David W
Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Veterans Administration Chicago Health Care System, Chicago, IL 60611, USA.
Am J Respir Cell Mol Biol. 2004 Jul;31(1):107-13. doi: 10.1165/rcmb.2003-0064OC. Epub 2004 Feb 19.
Fibroblast growth factor-10 (FGF-10), an alveolar epithelial cell (AEC) mitogen that is critical for lung development, may promote AEC repair. We determined whether FGF-10 attenuates H2O2-induced, A549 and rat alveolar type II cell DNA damage. We show that FGF-10 prevents H2O2-induced DNA damage assessed by an alkaline elution, ethidium bromide fluorescence as well as by a comet assay. Mitogen-activated protein kinase inhibitors abolished the protective effect of FGF-10 against H2O2-induced DNA damage yet had no effect on H2O2-induced DNA damage. A Grb2-SOS inhibitor (SH3 binding peptide), an Ras inhibitor (farnesyl transferase inhibitor 277), and an Raf-1 inhibitor (forskolin) each prevented FGF-10- and H2O2-induced A549 cell ERK1/2 phosphorylation. Also, FGF-10 and H2O2 each induced negligible ERK1/2 phosphorylation in Ras dominant-negative (N17) cells. Inhibitors of Ras and Raf-1 blocked the protective effect of FGF-10 against H2O2-induced DNA damage but had no effect on H2O2-induced DNA damage. Furthermore, cold conditions and aphidicolin, an inhibitor of DNA polymerase-alpha, -delta, and -epsilon, each blocked the protective effects of FGF-10, suggesting a role for DNA repair. We conclude that FGF-10 attenuates H2O2-induced AEC DNA damage by mechanisms that involve activation of Grb2-SOS/Ras/RAF-1/ERK1/2 pathway and DNA repair.
成纤维细胞生长因子10（FGF - 10）是一种对肺发育至关重要的肺泡上皮细胞（AEC）促分裂原，可能促进AEC修复。我们确定了FGF - 10是否能减轻过氧化氢（H2O2）诱导的A549细胞和大鼠肺泡II型细胞的DNA损伤。我们发现，通过碱性洗脱、溴化乙锭荧光以及彗星试验评估，FGF - 10可预防H2O2诱导的DNA损伤。丝裂原活化蛋白激酶抑制剂消除了FGF - 10对H2O2诱导的DNA损伤的保护作用，但对H2O2诱导的DNA损伤没有影响。一种Grb2 - SOS抑制剂（SH3结合肽）、一种Ras抑制剂（法尼基转移酶抑制剂277）和一种Raf - 1抑制剂（福斯高林）均可阻止FGF - 10和H2O2诱导的A549细胞ERK1/2磷酸化。此外，FGF - 10和H2O2在Ras显性阴性（N17）细胞中各自诱导的ERK1/2磷酸化可忽略不计。Ras和Raf - 1抑制剂阻断了FGF - 10对H2O2诱导的DNA损伤的保护作用，但对H2O2诱导的DNA损伤没有影响。此外，低温条件和DNA聚合酶α、δ和ε的抑制剂阿非科林均可阻断FGF - 10的保护作用，提示DNA修复发挥了作用。我们得出结论，FGF - 10通过涉及激活Grb2 - SOS/Ras/RAF - 1/ERK1/2途径和DNA修复的机制减轻H2O2诱导的AEC DNA损伤。
