Studies on specific genes in the brain induced by DOPA and their function.

为了阐明左旋多巴抗帕金森药物治疗帕金森病的脑内分子事件，我们对左旋多巴特异性诱导的帕金森模型动物黑质纹状体通路基因进行了研究，并分析了其功能，具体如下：1。左旋多巴治疗后帕金森模型脑内表达基因的筛选采用差异显示法筛选左旋多巴治疗后半帕金森模型大鼠纹状体中表达的特异性基因。一个促凋亡基因p53-活化基因608（PAG608）被鉴定为多巴胺诱导的帕金森病脑基因2。PAG608在氧化应激诱导的多巴胺能神经元细胞凋亡中的作用在儿茶酚胺能细胞中，转染反义PAG608 cDNA抑制PAG608表达可阻断6-羟多巴胺或过氧化氢诱导的细胞死亡，p53和Bax表达增加，线粒体膜电位降低，caspase-3活化和DNA断裂。虽然PAG608可以被p53激活，但转染PAG608基因后过表达PAG608会使p53的表达呈负向增加。此外，我们明确了PAG608易位到细胞核和核核是诱导细胞凋亡的必要条件。PAG608参与多巴胺或甲基苯丙胺诱导的神经毒性转染反义PAG608 cDNA抑制PAG608的表达也阻断过量多巴胺或甲基苯丙胺诱导的多巴胺能细胞死亡和凋亡形态学改变。左旋多巴处理的帕金森模型大鼠脑内PAG608的表达，PAG608在脑桥核、三叉神经运动核和面神经中组成性表达。在左旋多巴处理组的内囊中，PAG608在帕金森侧强烈表达。这些实验结果表明，PAG608普遍参与左旋多巴或甲基苯丙胺治疗导致多巴胺能神经元死亡的共同通路，是帕金森模型基底神经节中过量多巴胺特异性诱导的分子。少

To clarify the molecular events in the brain of parkinsonian who treated with levodopa of anti-parkinsonian drugs, we investigated the genes in the nigrostriatal pathway of parkinsonian model animals specifically induced by levodopa treatment, and also analyzed their function, as follows :1.Screening of expressed genes in the brain of parkinsonian models after levodopa treatmentWe screened the specific genes which expressed in the striatum of hemi-parkinsonian model rats after levodopa treatment by using differential display method. A proapoptotic gene, p53-activated gene 608(PAG608) was identified as a DOPA-induced gene in parkinsonian brain.2.Role of PAG608 in oxidative stress-induced apoptosis in dopaminergic neuronal cellsIn the catecholaminergic cells, inhibition of PAG608 expression by the transfection with antisense PAG608 cDNA blocked 6-hydroxydopamine-or hydrogen peroxide-induced cell death, increases in p53 and Bax expression, reduction of mitochondrial membrane potential, ac … More tivation of caspase-3 and DNA fragmentation. Although PAG608 is activated by p53, overexpression of PAG608 by the transfection of PAG608 gene inversely increased p53 expression. Furthermore, we clarified that the translocation of PAG608 to the nucleus and nucleolus is necessary for induction of apoptosis.3.Involvement of PAG608 in_dopamine-or methamphetamine-induced neurotoxicityThe inhibition of PAG608 expression by the transfection with antisense PAG608 cDNA also blocked excess dopamine-or methamphetamine-induced dopaminergic cell death and their apoptotic morphological changes.4.Expression of PAG608 in the brain of levodopa-treated parkinsonian model ratsPAG608 constitutively expressed in the pontine nucleus, motor nuclei of trigeminal nerve and facial nerve. In the internal capsule, PAG608 expression was strongly induced in the parkinsonian side of levodopa-treated group.These experimental results suggest that PAG608 is generally involved in the common pathway of dopaminergic neuronal death induced by the treatment of levodopa or methamphetamine and that it is a molecule specifically induced by excess amount of dopamine in the basal ganglia of parkinsonian models. Less