US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA.
Acta Pharmacol Sin. 2010 Feb;31(2):175-83. doi: 10.1038/aps.2009.190.
To test the hypothesis that PI3K/Akt/eNOS signaling has a protective role in a murine model of ventilation associated lung injury (VALI) through down-regulation of p38 MAPK signaling.
Male C57BL/J6 (wild-type, WT) or eNOS knockout mice (eNOS(-/-)) were exposed to mechanical ventilation (MV) with low (LV(T), 7 mL/kg) and high tidal volume (HV(T), 20 mL/kg) for 0-4 h. A subset of WT mice was administered the specific inhibitors of PI3K (100 nmol/L Wortmannin [Wort], ip) or of p38 MAPK (SB203580, 2 mg/kg, ip) 1 h before MV. Cultured type II alveolar epithelial cells C10 were exposed to 18% cyclic stretch for 2 h with or without 20 nmol/L Wort pretreatment. At the end of the experiment, the capillary leakage in vivo was assessed by extravasation of Evans blue dye (EBD), wet/dry weight ratio and lung lavage protein concentration. The lung tissue and cell lysate were also collected for protein and histological review.
MV decreased PI3K/Akt phosphorylation and eNOS expression but increased phospho-p38 MAPK expression along with a lung leakage of EBD. Inhibitions of phospho-Akt by Wort worsen the lung edema, whereas inhibition of p38 MAPK kinase restored activation of Akt together with alleviated capillary leakage. eNOS(-/-) mice showed an exacerbated lung edema and injury. The stretched C10 cells demonstrated that Wort diminished the activation of Akt, but potentiated phosphorylation of MAPK p38.
Our results indicate that PI-3K/Akt/eNOS pathway has significant protective effects in VALI by preventing capillary leakage, and that there is a cross-talk between PI3K/Akt and p38 MAPK pathways in vascular barrier dysfunction resulting from VALI.
通过下调 p38MAPK 信号通路，检验磷脂酰肌醇 3-激酶（PI3K）/蛋白激酶 B（Akt）/内皮型一氧化氮合酶（eNOS）信号通路在机械通气相关性肺损伤（VALI）的小鼠模型中具有保护作用这一假说。
雄性 C57BL/J6（野生型，WT）或 eNOS 敲除（eNOS(-/-)）小鼠分别接受低（LV(T)，7ml/kg）和高（HV(T)，20ml/kg）潮气量的机械通气（MV）0-4 小时。一部分 WT 小鼠在 MV 前 1 小时接受 PI3K 特异性抑制剂（100nmol/L Wortmannin[Wort]，腹腔内注射）或 p38MAPK 特异性抑制剂（SB203580，2mg/kg，腹腔内注射）预处理。2 小时内对培养的 II 型肺泡上皮细胞 C10 进行 18%周期性拉伸，部分细胞用 20nmol/L Wort 预处理。实验结束时，通过 Evans 蓝染料（EBD）外渗评估体内毛细血管渗漏，检测湿/干重比和肺灌洗蛋白浓度。还收集肺组织和细胞裂解物进行蛋白和组织学评价。
MV 降低了 PI3K/Akt 磷酸化和 eNOS 表达，但增加了磷酸化 p38MAPK 表达，同时伴有 EBD 肺漏。Wort 抑制磷酸化 Akt 会加重肺水肿，而抑制 p38MAPK 激酶则恢复 Akt 激活并减轻毛细血管渗漏。eNOS(-/-)小鼠表现出更严重的肺水肿和损伤。拉伸的 C10 细胞表明 Wort 降低了 Akt 的激活，但增强了 MAPK p38 的磷酸化。
我们的结果表明，PI-3K/Akt/eNOS 通路通过防止毛细血管渗漏在 VALI 中具有显著的保护作用，并且在 VALI 导致的血管屏障功能障碍中，PI3K/Akt 和 p38MAPK 通路之间存在交叉对话。
