Irving E A, Barone F C, Reith A D, Hadingham S J, Parsons A A
Department of Neuroscience Research, SmithKline Beecham Pharmaceuticals, New Frontiers Science Park, (N) H25/121, Harlow, UK.
Brain Res Mol Brain Res. 2000 Apr 14;77(1):65-75. doi: 10.1016/s0169-328x(00)00043-7.
Two relatively well characterised kinase signalling pathways are those involving MAPK/ERK and p38/SAPK2, that are known to be activated in vitro by various factors known to increase following stroke, such as glutamate, IL-1 and TNF. The present study was designed to investigate the activation and cellular distribution of phosphorylated-ERK1/2, -p38 and the transcription factor CREB following focal cerebral ischaemia using phosphospecific antibodies. Up to 24 h following transient MCAO (90 min) and 6 h following permanent MCAO, phospho-ERK1/2 staining was markedly increased within the cytoplasm of neuronal perikarya in 'penumbral-like' regions. In contrast, phospho-p38 immunostaining was markedly increased in cells with astrocyte-like morphology in both 'core' and 'penumbral-like' regions. Phospho-p38 staining was also detected in some neurones within 'penumbral-like' regions up to 24 h following transient MCAO. CREB activation was confined to neurones in 'penumbral-like' regions. Increased phospho-p38 immunoreactivity was detected in astrocyte-like cells present in the subcortical white matter ipsilateral to the occluded MCAO, while phospho-CREB and -ERK1/2 staining was localised to cells with the morphological appearance of oligodendrocytes. This study demonstrates phosphorylation, indicative of activation, of both the MAPK and p38 pathways following transient and permanent MCAO. However, each pathway shows a distinct cellular and spatial distribution within ischaemic tissue. Together these data indicate that neuroprotection offered by agents directed towards the ERK1/2 pathway may act directly through protection of neurones and oligodendrocytes, while those directed towards the p38 pathway kinase signalling pathways may be indirectly via inhibition of cytokines and other mediators involved in the brains response to injury.
两条相对特征明确的激酶信号通路是涉及MAPK/ERK和p38/SAPK2的通路，已知这些通路在体外可被中风后增加的各种因素激活，如谷氨酸、白细胞介素-1和肿瘤坏死因子。本研究旨在使用磷酸特异性抗体研究局灶性脑缺血后磷酸化-ERK1/2、-p38和转录因子CREB的激活及细胞分布。短暂性大脑中动脉闭塞（90分钟）后长达24小时以及永久性大脑中动脉闭塞后6小时，在“半暗带样”区域神经元胞体的细胞质内，磷酸化-ERK1/2染色显著增加。相比之下，在“核心区”和“半暗带样”区域，具有星形胶质细胞样形态的细胞中磷酸化-p38免疫染色显著增加。短暂性大脑中动脉闭塞后长达24小时，在“半暗带样”区域的一些神经元中也检测到磷酸化-p38染色。CREB激活局限于“半暗带样”区域的神经元。在闭塞大脑中动脉同侧的皮质下白质中存在的星形胶质细胞样细胞中检测到磷酸化-p38免疫反应性增加，而磷酸化-CREB和-ERK1/2染色定位于具有少突胶质细胞形态外观的细胞。本研究表明，短暂性和永久性大脑中动脉闭塞后，MAPK和p38通路均发生了指示激活的磷酸化。然而，每条通路在缺血组织内显示出独特细胞和空间分布。这些数据共同表明，针对ERK1/2通路的药物提供的神经保护作用可能直接通过保护神经元和少突胶质细胞发挥作用，而针对p38通路激酶信号通路的药物可能间接通过抑制参与大脑对损伤反应的细胞因子和其他介质发挥作用。
