Vikman Petter, Ansar Saema, Henriksson Marie, Stenman Emelie, Edvinsson Lars
Department of Clinical Sciences, Experimental Vascular Research, BMC A13, 221 84, Lund, Sweden.
Exp Brain Res. 2007 Dec;183(4):499-510. doi: 10.1007/s00221-007-1062-5. Epub 2007 Sep 8.
Cerebral ischemia results in a local inflammatory response that contributes to the size of the lesion, however, the involvement of the cerebral vasculature is unknown. We hypothesise that the expression of inflammatory genes (Il6, iNOS, cxcl2, TNF-alpha and Il-1beta) and extracellular-matrix-related genes (MMP9, MMP13) is induced in cerebral arteries following cerebral ischemia via activation of mitogen activated kinases (MAPKs). This hypothesis was tested in vivo by experimental subarachnoid haemorrhage (SAH) and temporal middle cerebral artery occlusion (MCAO), and by organ culture of isolated cerebral arteries with quantitative real time PCR (mRNA expression) and immunohistochemistry (localization of protein expression). The gene promoters were investigated in silica with computer analysis. The mRNA analysis revealed that the ischemic models, SAH and MCAO, as well as organ culture of isolated cerebral arteries resulted in transcriptional upregulation of the abovementioned genes. The protein expression involved phosphorylation of three different MAPKs signalling pathways (p38, ERK 1/2 and SAPK/JNK) and the downstream transcription factors (ATF-2, Elk-1, c-Jun) shown by immunohistochemistry and quantified by image analysis. All three models revealed the same pattern of activation in the cerebrovascular smooth muscle cells. The in silica analysis demonstrated binding sites for said transcription factors. The results suggest that cerebral ischemia and organ culture induce activation of p38, ERK 1/2 and SAPK/JNK in cerebral arteries which in turn activate the transcription factors ATF-2, Elk-1 and c-Jun and the expression of inflammatory and extracellular-matrix-related genes in the wall of cerebral arteries.
脑缺血会引发局部炎症反应，这种反应会影响损伤的大小，然而，脑脉管系统在其中所起的作用尚不清楚。我们推测，脑缺血后，有丝分裂原激活的蛋白激酶（MAPK）被激活，从而诱导脑动脉中炎症基因（Il6、iNOS、cxcl2、TNF-α和Il-1β）以及细胞外基质相关基因（MMP9、MMP13）的表达。我们通过实验性蛛网膜下腔出血（SAH）和颞中动脉闭塞（MCAO）在体内验证了这一推测，并通过定量实时聚合酶链反应（mRNA表达）和免疫组织化学（蛋白表达定位）对分离的脑动脉进行器官培养来验证。利用计算机分析在硅中对基因启动子进行了研究。mRNA分析显示，缺血模型SAH和MCAO以及分离的脑动脉器官培养均导致上述基因的转录上调。免疫组织化学显示并通过图像分析定量，蛋白表达涉及三种不同的MAPK信号通路（p38、ERK 1/2和SAPK/JNK）以及下游转录因子（ATF-2、Elk-1、c-Jun）的磷酸化。所有三种模型在脑血管平滑肌细胞中均显示出相同的激活模式。在硅中的分析表明存在所述转录因子的结合位点。结果表明，脑缺血和器官培养可诱导脑动脉中p38、ERK 1/2和SAPK/JNK的激活，进而激活转录因子ATF-2、Elk-1和c-Jun，并诱导脑动脉壁中炎症和细胞外基质相关基因的表达。
