Gross J, Moller R, Amarjargal N, Machulik A, Fuchs J, Ungethüm U, Kuban R J, Henke W, Haupt H, Mazurek B
Department of Otorhinolaryngology, Molecular Biology Research Laboratory, Charité - Universitätsmedizin Berlin, Berlin, Germany.
Prague Med Rep. 2009;110(4):310-31.
Recently we have demonstrated that recombinant human erythropoietin (EPO) protects neurosensory hair cells in the organotypic culture of the organ of Corti by reducing apoptosis and necrosis. In the present study, we tested the hypothesis that EPO may be involved in reparative angiogenesis. We analyzed in parallel the endogenous erythropoietin (Epo) mRNA expression and that of Epo receptor (Epor) and of genes associated with angiogenesis in the organ of Corti, the modiolus and the stria vascularis using real time reverse transcription polymerase chain reaction and microarray. We compared the expression levels of freshly prepared tissue (control) and tissue cultured for 24 h under normoxia or hypoxia. The basal expression of Epo- and Epor mRNA in controls of all regions was very low. However, after 24 h in culture, a 20-100 fold increase of these two transcripts was measured. In culture, the vascular endothelial growth factor and the Cxcr4 (the receptor for the stromal cell-derived factor-1, Sdf-1) mRNA levels, were found to be increased and the Sdf-1 mRNA level to be decreased. Changes in mRNA expression occurred in all pathways activated in non-erythroid cells by the application of EPO (phosphoinositide 3-kinase/serine-threonine protein kinase B, Janus-type protein tyrosine kinase 2/signal transducer and activator of transcription 3, and the mitogen activated protein kinase). These data suggest that the neuroprotective effect of EPO may include at least two molecular events, the decrease of hair cell death rate and the induction of angiogenic genes.
最近我们已经证明，重组人促红细胞生成素（EPO）通过减少凋亡和坏死，在柯蒂氏器的器官型培养物中保护神经感觉毛细胞。在本研究中，我们测试了EPO可能参与修复性血管生成的假设。我们使用实时逆转录聚合酶链反应和微阵列，并行分析了柯蒂氏器、蜗轴和血管纹中内源性促红细胞生成素（Epo）mRNA表达、Epo受体（Epor）以及与血管生成相关基因的表达。我们比较了新鲜制备的组织（对照）以及在常氧或缺氧条件下培养24小时的组织的表达水平。所有区域对照中Epo和Epor mRNA的基础表达都非常低。然而，培养24小时后，这两种转录本的水平增加了20 - 100倍。在培养过程中，发现血管内皮生长因子和Cxcr4（基质细胞衍生因子-1即Sdf-1的受体）的mRNA水平升高，而Sdf-1的mRNA水平降低。EPO应用于非红细胞系细胞时激活的所有途径中均发生了mRNA表达变化（磷酸肌醇3激酶/丝氨酸-苏氨酸蛋白激酶B、Janus型蛋白酪氨酸激酶2/信号转导子和转录激活子3以及丝裂原活化蛋白激酶）。这些数据表明，EPO的神经保护作用可能至少包括两个分子事件，即毛细胞死亡率的降低和血管生成基因的诱导。
