Huashan Hospital, Institute of Nephrology, Fudan University, Shanghai, China.
Am J Nephrol. 2010;31(6):490-500. doi: 10.1159/000304289. Epub 2010 May 6.
The vasculature plays a key role in the progression of renal damage in aging, with reduction in glomerular and peritubular capillary density and decreased endothelial proliferative response. In this study, we examined the role of angiopoietin-1 (Ang1) in H(2)O(2)-induced senescence in mouse glomerular endothelial cells (MGECs) and the signaling pathway involved.
MGECs were subjected to H(2)O(2)-induced senescence, which was evaluated by senescence-associated beta-galactosidase (SA-beta-Gal) staining, cell cycle analysis and expression of p16. Endothelial cell function was assessed by nitric oxide, von Willebrand factor secretion and capillary-like structure formation. Signal transduction was examined by Western blot with or without a specific inhibitor.
Ang1 significantly inhibited H(2)O(2)-induced senescence in MGECs, attenuated SA-beta-Gal activity, resumed growth, and downregulated p16(INK4a) levels. Moreover, Ang1 regulated the secretion and capillary-like structure formation of endothelial cells with aging. However, these changes were markedly blocked by treatment with Ang2, sTie2-Fc and PD98059. Ang1 treatment markedly increased elevated Tie2 and ERK1/2 phosphorylation levels which were reduced by Ang2 and sTie2-Fc. PD98059 substantially reduced senescence while not altering Ang1-stimulated phosphor-Tie2 stimulation.
The present studies suggest that Ang1 inhibits H(2)O(2)-induced senescence in MGECs via the Ang1-Tie2-ERK1/2 signaling pathway.
血管系统在衰老导致的肾脏损害进展中起着关键作用，肾小球和肾小管周围毛细血管密度降低，内皮细胞增殖反应减弱。在这项研究中，我们研究了血管生成素-1（Ang1）在 H2O2 诱导的小鼠肾小球内皮细胞（MGEC）衰老中的作用及其相关信号通路。
将 MGEC 暴露于 H2O2 诱导的衰老中，通过衰老相关β-半乳糖苷酶（SA-β-Gal）染色、细胞周期分析和 p16 表达评估衰老。通过一氧化氮、血管性血友病因子分泌和毛细血管样结构形成评估内皮细胞功能。用或不用特定抑制剂进行 Western blot 检测信号转导。
Ang1 显著抑制 H2O2 诱导的 MGEC 衰老，减弱 SA-β-Gal 活性，恢复生长，并下调 p16（INK4a）水平。此外，Ang1 调节衰老内皮细胞的分泌和毛细血管样结构形成。然而，这些变化被 Ang2、sTie2-Fc 和 PD98059 明显阻断。Ang1 处理显著增加 Tie2 和 ERK1/2 磷酸化水平，而 Ang2 和 sTie2-Fc 降低了这些水平。PD98059 显著减少衰老，而不改变 Ang1 刺激的 Tie2 磷酸化刺激。
本研究表明，Ang1 通过 Ang1-Tie2-ERK1/2 信号通路抑制 H2O2 诱导的 MGEC 衰老。
