Sp4 Pathway in the Modulation of Sensorimotor Gating and Memory

描述（由申请人提供）：基于遗传操作的动物模型可以极大地促进我们对大脑疾病的理解。Sp 4转录因子表达减少的突变小鼠在感觉运动门控和背景学习方面表现出缺陷，类似于精神分裂症的假定内表型。Sp 4基因与精神分裂症和双相情感障碍显著相关。在小鼠研究中，Sp 4基因表达减少损害海马CA 1区的长时程增强（LTP），损害空间学习能力，并显著降低NMDA谷氨酸受体核心亚基NMDAR 1的表达。NMDA功能受损在精神分裂症的病理生理学中起着核心作用。这种新的Sp 4-NMDAR 1通路的鉴定为与人类精神疾病相关的跨物种研究提供了基础。这个更新的应用程序研究如何Sp 4调节NMDAR 1蛋白的表达，以调节参与感觉运动门控和认知功能的神经通路。核心假设是Sp 4转录后调节NMDAR 1的表达，并且在特定脑区域中恢复Sp 4-NMDAR 1表达将逆转Sp 4亚型小鼠的感觉运动门控和认知缺陷。四个具体的目的将测试这些假设：目的1：阐明野生型和Sp 4亚纯型小鼠之间的NMDAR 1蛋白的差异表达的分子机制。通过原位杂交检测NMDAR 1 mRNA的定位。将使用TimeSTAMP 2.2-Venus标签检查NMDAR 1蛋白的差异翻译和转换。目的2：通过恢复兴奋性和抑制性神经元中Sp 4-NMDAR 1的表达来逆转感觉运动门控缺陷。Sp 4-NMDAR 1的表达将在新皮层和海马的兴奋性和抑制性神经元中恢复，以逆转Sp 4低形态小鼠中的前脉冲抑制门控缺陷。分子和药理学研究将进一步表征条件性获救小鼠。目标3：确定Sp 4亚纯型小鼠是否表现出由额叶皮质调节的认知缺陷，以及额叶皮质中Sp 4-NR 1表达的恢复是否会逆转这些缺陷。注意力转移任务和气味范围任务都将用于检查Sp 4亚纯型和条件性获救小鼠的认知功能。目标4：测试海马CA 1区Sp 4表达的恢复是否足以逆转Sp 4亚型的LTP和空间学习缺陷。通过将CamK 2a-Cre和Sp 4亚纯型小鼠杂交，将在CA 1中恢复Sp 4-NMDAR 1表达。将在携带CamK 2a-Cre的Sp 4亚型小鼠中检查空间和背景记忆的形成和巩固。这些研究将有助于阐明感觉运动门控和学习调节的分子机制，并有助于临床干预措施的发展，以防止Sp 4-NMDAR 1通路在人类精神疾病中的下调。 公共卫生相关性：Sp 4基因最近被认为与精神分裂症和双相情感障碍有关，它编码脑细胞中一种重要的转录因子，调节与精神障碍中的认知障碍有关的多巴胺能受体的功能。该项目旨在使用动物模型来阐明与精神分裂症中特定认知异常相关的分子机制，以帮助开发临床干预措施，以预防人类精神疾病中Sp 4-谷氨酸途径的失调。

DESCRIPTION (provided by applicant): Animal models based on genetic manipulations can contribute enormously to our understanding of diseases of the brain. Mutant mice with reduced expression of the Sp4 transcription factor display deficits in sensorimotor gating and contextual learning that resemble putative endophenotypes for schizophrenia. The Sp4 gene is significantly associated with schizophrenia and bipolar disorder. In mouse studies, reduced expression of the Sp4 gene impaired long-term potentiation (LTP) in hippocampal CA1, impaired spatial learning, and markedly decreased the expression of NMDAR1, the core subunit for NMDA glutamate receptors. Impaired NMDA function plays a central role in the pathophysiology of schizophrenia. This identification of a novel Sp4-NMDAR1 pathway provides a basis for cross-species studies related to human psychiatric disorders. This renewal application investigates how Sp4 regulates expression of NMDAR1 proteins to modulate neural pathways involved in sensorimotor gating and cognitive functions. The central hypotheses are that Sp4 post-transcriptionally regulates the expression of NMDAR1 and that restoration of Sp4-NMDAR1 expression in specific brain regions will reverse both sensorimotor gating and cognitive deficits in Sp4 hypomorphic mice. Four Specific Aims will test these hypotheses: Aim 1: To elucidate molecular mechanisms for differential expression of NMDAR1 proteins between wildtype and Sp4 hypomorphic mice. The localization of NMDAR1 mRNA will be examined by in situ hybridization. The differential translation and turnover of NMDAR1 proteins will be examined using TimeSTAMP2.2-Venus tag. Aim 2: To reverse deficient sensorimotor gating by restoring Sp4-NMDAR1 expression in excitatory and inhibitory neurons respectively. The expression of Sp4-NMDAR1 will be restored in excitatory and inhibitory neurons of both neocortex and hippocampus, to reverse prepulse inhibition gating deficits in Sp4 hypomorphic mice. Molecular and pharmacological studies will further characterize the conditional rescued mice. Aim 3: To determine whether Sp4 hypomorphic mice exhibit cognitive deficits modulated by the frontal cortex, and whether restoration of Sp4-NR1 expression in frontal cortex will reverse these deficits. Both the Attentional-Set-Shifting Task and the Odor Span Task will be used to examine cognitive functions in Sp4 hypomorphic and conditional rescued mice. Aim 4: To test whether restoration of Sp4 expression in hippocampal CA1 is sufficient to reverse the LTP and spatial learning deficits in Sp4 hypomorphs. Sp4- NMDAR1 expression will be restored in CA1 by crossing CamK2a-Cre and Sp4 hypomorphic mice. The formation and consolidation of spatial and contextual memories will be examined in the Sp4 hypomorphic mice harboring CamK2a-Cre. The proposed studies will help elucidate molecular mechanisms underlying the modulation of sensorimotor gating and learning, and aid the development of clinical interventions to prevent the down-regulation of Sp4-NMDAR1 pathway in human psychiatric disorders. PUBLIC HEALTH RELEVANCE: The Sp4 gene, which has recently been associated with both schizophrenia and bipolar disorder, codes for an important transcription factor in brain cells that regulates the function of glutamatergic receptors involved in the cognitive impairments in psychiatric disorders. This project seeks to use animal models to elucidate molecular mechanisms related to specific cognitive abnormalities in schizophrenia, in order to aid the development of clinical interventions to prevent the dysregulation of the Sp4-glutamate pathway in human psychiatric disorders.