Genetic Models of Serotonin Transporter Regulation Linked to Mental Disorders

描述（由申请人提供）：5-羟色胺能传递和突触前5-羟色胺（5-羟色胺，5-HT）转运蛋白（SERT）表达的改变长期以来与精神疾病有关，包括抑郁症，自杀，自闭症，强迫症，冲动暴力。事实上，阻断SERT的药物，如三环抗抑郁药和SSRIs，已经成功地用于治疗精神障碍。PI的研究小组、合作者和同事已经确定了激酶/磷酸酶调控SERT的信号机制。值得注意的是，人类SERT编码变体Gly56Ala、Ile425Val突变与强迫症、自闭症和其他精神疾病的关联，以及这些突变改变PKG/p38 MAPK对SERT活性的调节的发现表明，这种形式的调节在SERT的正常生理中很重要，SERT的失调可能会影响5-HT信号受损导致的疾病风险。目前还没有转基因动物模型来测试SERT磷酸化的改变是否会导致自闭症、强迫症和其他精神疾病的行为改变。在这项R21提案中，认识到风险与回报的任务，我们提出验证这样的假设，即模拟组成性SERT pkg -磷酸化的转基因小鼠模型显示出5-HT转运表型的增加，pkg介导的上调和磷酸化挽救行为表型的丧失，这些行为表型与强迫症和阿斯伯格综合征中发现的Ile425Val突变相似。在Specific Aim 1中，我们提出构建携带Thr276Asp突变的靶向载体，模拟与强迫症和阿斯伯格综合征相关的pkg磷酸化和Ile425Val突变，将该突变插入小鼠SERT基因组序列中，产生SERT转基因小鼠。Specific Aim 2将验证Thr276Asp和Ile425Val SERT小鼠的SERT调控和磷酸化，并阐明敲入小鼠中拯救的重要5-HT相关行为表型。然而，超出本提案范围的未来研究将利用Thr276Asp和/或Ile425Val敲入SERT小鼠来分析神经化学、行为和基因表达谱，并测量体内急性和慢性SSRI治疗和其他治疗药物的反应。因此，这些独特小鼠模型的产生为探索激酶介导的SERT调控途径提供了创新工具，这些途径是在疾病相关的人类SERT变异中发现的破坏正常SERT功能的设定点。此外，这些SERT转基因小鼠将有助于未来的研究探索可能与精神障碍有关的血清素相关基因调控网络，并有助于开发治疗精神障碍的有效药物。

DESCRIPTION (provided by applicant): Altered serotonergic transmission and presynaptic serotonin (5-hydroxytryptamine, 5-HT) transporter (SERT) expression have long been associated with psychiatric disorders including depression, suicide, autism, OCD, impulsive violence. Indeed, the drugs that block SERT such as tricyclic antidepressants and SSRIs are successfully used for the treatment of mental disorders. Studies from PI's group, collaborators and colleagues have identified signaling mechanisms of SERT regulation by kinases/phosphatases. Remarkably, the association of human SERT coding variants Gly56Ala, Ile425Val mutation with OCD, autism and other psychiatric disorders, and the discovery that these mutations alter PKG/p38 MAPK regulation of SERT activity suggest that this form of regulation is important in the normal physiology of SERT and dysregulation of SERT may influence risk for disorders attributed to compromised 5-HT signaling. Currently no transgenic animal models are available to test whether altered SERT phosphorylation is causative for altered behavior found in autism, OCD and other psychiatric disorders. In this R21 proposal, recognizing the risk versus reward mission, we propose to test the hypothesis that transgenic mouse models mimicking constitutive SERT PKG-phosphorylation show gain of 5-HT transport phenotype with loss of PKG-mediated upregulation and phosphorylation rescuing behavioral phenotypes that parallel Ile425Val mutant identified in OCD and Asperger syndrome. In Specific Aim 1, we propose to construct targeting vectors carrying Thr276Asp mutation that mimic PKG-phosphorylation and Ile425Val mutation associated with OCD and Asperger syndrome by inserting the mutations into mouse SERT genomic sequences to generate SERT transgenic SERT mice. Specific Aim 2 will validate SERT regulation and phosphorylation in Thr276Asp and Ile425Val SERT mice, and elucidate important 5-HT related behavioral phenotypes rescued in the knock-in mice. However, future studies that are beyond the scope of this proposal, will utilize Thr276Asp and/or Ile425Val knock-in SERT mice to analyze neurochemical, behavioral and gene expression profiles, and to measure responses to acute and chronic in vivo SSRI administrations and other therapeutic agents. Thus, generation of these unique mouse models provide innovative tools for exploring the kinase mediated SERT regulatory pathways that are set points in disrupting normal SERT function found in disease-linked human SERT variants. In addition, these SERT transgenic mice will aid future studies exploring serotonin-related gene regulatory network that may be linked to mental disorders and in the development of effective pharmacological agents for the treatment of mental disorders. PUBLIC HEALTH RELEVANCE: The association of human SERT coding variants Gly56Ala, Ile425Val mutation with OCD, autism and other psychiatric disorders, and the discovery that these mutants alter PKG/p38 MAPK regulation of SERT activity suggest that this form of regulation is important in the normal physiology of SERT. The proposed research to generate a knock-in mouse model will enable to identify the neuronal network linked to mental disorders and aid in the development of effective pharmacological agents for the treatment of mental disorders and other disease states resulting from aberrant monoamine transmission.