Generation and Characterization of GAD67-ErbB4 Transgenic Mice

描述(申请人提供)：精神分裂症是一种复杂的精神障碍，由于人脑和鼠脑的结构差异，缺乏明确的病理特征，以及小鼠无法表现出人类的精神表型，如妄想、幻觉或抑郁，因此在啮齿动物身上建立模型极其困难。这主张建立模型，在行为、生理和分子分析中创建具有离散终点的精神分裂症不同成分的零碎。事实证明，这种方法在建立和分析精神分裂症啮齿动物模型方面很有用。神经调节蛋白-1(NRG1)及其受体ErbB4都是精神分裂症的易感基因。最近的证据表明，精神分裂症患者前额叶皮质(PFC)中NRG1信号的功能增强。精神分裂症患者的PFC中I型NRG1和细胞色素T-1/JMA ErbB4的表达增加。此外，精神分裂症患者死后大脑同一区域的NRG1信号也被发现增强。尽管有临床证据表明NRG1/ErbB4在精神分裂症中功能获得，但还没有这样的啮齿动物模型。这似乎是进一步在体内研究NRG1和ErbB4突变的细胞、分子和行为缺陷以及病理机制的瓶颈。在初步研究中，我们证明了NRG1通过ErbB4调节PFC中活性依赖的GABA释放。因此，我们建议建立并鉴定过表达人细胞色素T-1/JMA ErbB4的GAD67-ErbB4转基因小鼠。R21阶段有三个特定的目的：1)GAD67-ErbB4转基因小鼠的产生；2)确定GAD67-ErbB4转基因小鼠的NRG1信号和诱导的活性依赖的GABA释放是否增加；以及3)NRG1对GAD67-ErbB4转基因小鼠GABA传递的调节是否增加。R33阶段有两个具体目标：1)确定NRG1抑制锥体神经元活动在GAD67-ErbB4小鼠中是否上调；2)确定GAD67-ErbB4转基因小鼠是否可以模拟精神分裂症的工作记忆缺陷、阳性和阴性症状以及注意缺陷。我们希望ErbB4信号的功能获得模型能够对NRG1和ErbB4这两个重要的易感基因的致病机制和致病途径提供重要的帮助。转基因小鼠可能对测试化学物质和生物试剂有用，这些化学物质和生物试剂可能有助于开发新的精神分裂症治疗干预措施。此外，GAD67-ErbB4转基因小鼠的成功制备和鉴定将为其他脑不同区域的NRG1功能获得模型提供原理证明。这是一项关于建立高表达人细胞色素T-1/JMA ErbB4的GAD67-ErbB4转基因小鼠的建议，以模拟精神分裂症的神经传递和行为障碍。ErbB4信号的功能获得模型将为了解精神分裂症的两个重要易感基因NRG1和ErbB4的致病机制和途径提供重要的信息。

DESCRIPTION (provided by applicant): Schizophrenia is a complex psychiatric disorder that is extremely difficult to model in rodents because of structural difference between human and mouse brains, lack of clear pathological hallmarks of the disorder, and inability of mice to demonstrate human psychiatric phenotypes such as delusion, hallucination, or depression. This argues for models to create a piecemeal of different components in schizophrenia with discrete endpoints in behavioral, physiological, and molecular analyses. Such an approach has proved useful in generating and analyzing schizophrenic rodent models. Both neuregulin-1 (NRG1) and its receptor ErbB4 are susceptibility genes of schizophrenia. Recent evidence suggests a gain-of-function of NRG1 signaling in the prefrontal cortex (PFC) in schizophrenic patients. Increased expression of type I NRG1 and CYT-1/JMa ErbB4 have been reported in the PFC of patients with schizophrenia. Moreover, NRG1 signaling was found to be enhanced in the same area of postmortem brains from schizophrenic patients. Despite of the clinic evidence for NRG1/ErbB4 gain-of-function in schizophrenia, there has not been such a rodent model. This appears to be a bottle neck for further in vivo studies of cellular, molecular as well as behavioral deficits and pathological mechanisms of NRG1 and ErbB4 mutations. In preliminary studies, we demonstrated that NRG1, via ErbB4, regulates activity-dependent GABA release in the PFC. Therefore, we propose to generate and characterize GAD67-ErbB4 transgenic mice overexpressing human CYT-1/JMa ErbB4. The R21 Phase has three Specific Aims: 1) Generation of GAD67-ErbB4 transgenic mice; 2) Determine whether NRG1 signaling and induced activity-dependent GABA release are increased in GAD67-ErbB4 transgenic mice; and 3) Determine whether NRG1 regulation of GABA transmission is increased in GAD67-ErbB4 transgenic mice. The R33 Phase has two Specific Aims: 1) Determine whether NRG1 suppression of pyramidal neuron activity is up-regulated in GAD67-ErbB4 mice and 2) Determine whether GAD67-ErbB4 transgenic mice can model working memory deficits, positive and negative symptoms and attentional deficits in schizophrenia. It is our hope that the gain-of- function model of ErbB4 signaling will provide critical insight into pathogenic mechanisms and pathways of NRG1 and ErbB4, two important susceptibility genes. The transgenic mice might be useful for testing chemicals and biological reagents that could facilitate the development of novel therapeutic interventions of schizophrenia. Moreover, successful generation and characterization of GAD67-ErbB4 transgenic mice will offer a proof of principle for other NRG1 gain-of-function models in different regions of the brain. This is a proposal to generate GAD67-ErbB4 transgenic mice over-expressing human CYT-1/JMa ErbB4 to model neurotransmission and behavioral deficits in schizophrenia. The gain-of-function model of ErbB4 signaling will provide critical insight into pathogenic mechanisms and pathways of NRG1 and ErbB4, two important susceptibility genes of schizophrenia.