Department of Neurobiology, College of Basic Medicine, China Medical University, Shengyang, Liaoning Province 110001, China.
Respirology. 2010 Jan;15(1):80-7. doi: 10.1111/j.1440-1843.2009.01648.x. Epub 2009 Nov 23.
Nerve growth factor (NGF) contributes to airway inflammation and bronchoconstriction in allergic asthma. The Src homology 2beta/serine/threonine kinase (SH2-Bbeta/Akt) pathway is one of the avenues through which NGF regulates the biological activity of pheochromocytoma (PC)12 cells. It has also been reported that NGF upregulates the expression of SH2-Bbeta in the lung tissue of asthmatic mice. The present study investigated the effects of NGF and SH2-Bbeta on Akt activation during allergic airway challenge.
BALB/c mice were sensitized and challenged with ovalbumin. The effects of NGF and SH2-Bbeta on Akt in allergic airway challenge were assessed by intravenously administering anti-NGF antibody or a mutant of SH2-Bbeta (R555E) to these mice. Pulmonary histological changes were then assessed and the inflammatory cells in the BAL fluid (BALF) were counted. Additionally, phosphorylated Akt (p-Akt) expression was determined by fluorescence microscopy, western blotting and quantitative RT-PCR. Airway resistance was also measured using closed-type body plethysmography.
We observed p-Akt overexpression in the lungs after allergen challenge by fluorescence microscopy, Western blotting and RT-PCR, as compared with the control. However, after treatment with anti-NGF or R555E, p-Akt levels and allergen-induced airway inflammation were reduced in comparison with those of allergen-challenged mice. Anti-NGF and R555E also decreased airway hyperresponsiveness caused by allergen challenge in response to methacholine (MCH).
These results suggest that SH2-Bbeta regulation of Akt partly participates in the NGF-mediated development of allergic airway challenge.
神经生长因子（NGF）参与变应性哮喘的气道炎症和支气管收缩。Src 同源 2β/丝氨酸/苏氨酸激酶（SH2-Bβ/Akt）途径是 NGF 调节嗜铬细胞瘤（PC）12 细胞生物学活性的途径之一。据报道，NGF 上调哮喘小鼠肺组织中 SH2-Bβ 的表达。本研究探讨了 NGF 和 SH2-Bβ 在变应原性气道挑战期间对 Akt 激活的影响。
用卵清蛋白对 BALB/c 小鼠进行致敏和激发。通过向这些小鼠静脉内给予抗 NGF 抗体或 SH2-Bβ 突变体（R555E），评估 NGF 和 SH2-Bβ 在变应原性气道挑战中对 Akt 的影响。然后评估肺组织学变化，并计数 BAL 液（BALF）中的炎症细胞。此外，通过荧光显微镜、Western blot 和定量 RT-PCR 测定磷酸化 Akt（p-Akt）的表达。还使用闭式体描仪测量气道阻力。
与对照组相比，我们通过荧光显微镜、Western blot 和 RT-PCR 观察到过敏原攻击后肺内 p-Akt 过度表达。然而，用抗 NGF 或 R555E 处理后，与过敏原激发的小鼠相比，p-Akt 水平和过敏原诱导的气道炎症降低。抗 NGF 和 R555E 还降低了 MCH 引起的过敏原激发导致的气道高反应性。
这些结果表明，SH2-Bβ 对 Akt 的调节部分参与了 NGF 介导的变应原性气道挑战的发生。
