Investigation of fragility factors related to cognitive dysfunction and neurodegeneration in animal models of schizophrenia

本研究试图从谷氨酸能系统功能障碍假说和神经发育假说出发，探讨精神分裂症样动物模型中情绪和认知障碍的分子机制。接受苯环利定(PCP：一种非竞争性NMDA受体拮抗剂)治疗的小鼠反复表现出情绪和认知障碍。重复PCP处理导致前额叶皮质(PFC)NMDA-CaMKII信号转导受损，细胞外自发谷氨酸水平降低。我们发现，通过宫内基因转移实现了额叶皮质锥体神经元DISC1基因的选择性敲除的小鼠，在青春期后出现了与青春期精神分裂症相关的中皮层多巴胺能投射和相关行为变化的成熟依赖性缺陷。这一策略允许以时间和空间特定的方式同时操纵发育过程中的多个因素，可以普遍应用于探索具有发育起源的重大精神疾病的发病途径。为了检测重复PCP处理后小鼠PFC中蛋白质表达的变化，我们利用荧光二维差示凝胶电泳法(2D-DGE)进行了蛋白质组分析。与生理盐水对照组相比，PCP处理组小鼠的9个蛋白点的相对丰度发生了变化。与生理盐水处理的小鼠相比，PCP处理的小鼠有7个蛋白质斑点增加，但有2个蛋白质斑点减少。经液-质联用鉴定的7个斑点分为3个功能类：细胞信号(5个斑点)、蛋白质降解(1个斑点)和能量代谢(1个斑点)。这些结果表明，PFC中蛋白表达的改变可能参与了重复服用五氯苯酚的小鼠精神分裂症样症状的分子机制。

We attempted to investigate the molecular mechanisms of emotional and cognitive deficits in schizophrenia-like animal models based on dysfunction hypothesis of glutamatergic systems and neurodevelopment. The mice treated with phencyclidine (PCP: a non-competitive NMDA receptor antagonist) repeatedly exhibited emotional and cognitive deficits. The repeated PCP treatment induced an impaired NMDA-CaMKII signaling and decreased spontaneous extracellular glutamate levels in the prefrontal cortex(PFC).We have found that the mice which via in utero gene transfer achieved selective knockdown of DISC1 in pyramidal neurons of the frontal cortex only during the development, showed maturation-dependent deficits in the mesocortical dopaminergic projections and associated behavioral changes relevant to schizophrenia after puberty. This strategy allows simultaneous manipulation of multiple factors during development in a temporally and spatially specific manner and could be applied generally to exploring disease pathways for major mental illnesses with developmental origins.To examine the changes in protein expression after repeated PCP treatment in PFC of mice, we performed proteomic analysis by using fluorescence two-dimensional difference gel electrophoresis (2D-DIGE). Changes in the relative abundance of 9 protein spots were observed in the PCP-treated mice compared to the saline-treated control mice. Seven spots exhibited an increase, but, 2 protein spots were decreased in the PCP-treated mice when compared to the saline-treated mice. Seven spots identified by liquid chromatographyttandem mass spectrometry were grouped into three functional classes; cell signaling (5 spots), protein degradation (1 spot) and energy metabolism (1 spot). These results suggest that altered protein expressions in the PFC may involve in the molecular mechanisms underlying the schizophrenia-like symptoms in repeated PCP-treated mice.