Mechanism of 5HT2AR regulation by Egr3

描述(申请人提供)：即刻早期基因早期生长反应3(EGR3)与精神分裂症有关，在死后患者的大脑中表达水平降低。我们之前已经报道过Egr3缺陷(-/-)小鼠表现出许多精神分裂症样的行为异常。此外，与野生型(WT)相比，他们对氯氮平镇静作用的敏感度降低，这与不明原因的临床观察相平行，即精神分裂症患者与健康对照组相比，对抗精神病药物副作用的耐受性显著增强。我们的初步研究表明，在Egr3-/-小鼠的前额叶皮质(PFC)中，近70%的5-羟色胺2A受体(5HT2AR)结合似乎是这种效应的机制。由于精神分裂症患者也表现出皮质5HT2ARs表达减少，这表明5HT2ARs的调节可能是Egr3影响精神分裂症风险的机制之一。本研究的目的是全面研究Egr3对5HT2AR调控的解剖学定位和分子机制，并确定哪些Egr3/-精神分裂症样行为异常与5HT2AR缺乏有关。在目标1中，我们将使用免疫组织化学和原位杂交从解剖学上确定5HT2AR在Egr3-/-小鼠中的表达。在目标2中，我们将使用定量RT-PCR来确定环境应激对Egr3调节Htr2a的能力。我们将通过染色质免疫沉淀和荧光素酶报告实验来验证Egr3通过启动子结合来调节Htr2a表达的假设。目的3提出利用病毒介导的5HT2AR过表达来“拯救”Egr3-/-小鼠的精神分裂症样表型，验证5HT2AR缺乏介导这些异常的假设。识别Egr3调节另一个精神分裂症易感基因的机制将增强我们对众多候选基因如何在生物途径中发挥作用以影响精神分裂症风险的理解。对这种途径的验证应该有助于阐明开发治疗这种破坏性疾病的新疗法的目标。 公共卫生相关性：拟议的研究旨在揭示参与精神分裂症易感性和治疗的两种不同蛋白质如何相互作用，以调节环境对这种严重精神疾病风险的影响。这项研究有可能阐明精神分裂症的病因，并揭示早期环境干预可以降低患精神分裂症的几率，精神分裂症是一种折磨1%的衰弱精神疾病。 占世界人口总数的一半。

DESCRIPTION (provided by applicant): The immediate early gene early growth response 3 (EGR3) is associated with schizophrenia and expressed at reduced levels in postmortem patients' brains. We have previously reported that Egr3-deficient (-/-) mice display numerous schizophrenia-like behavioral abnormalities. Moreover, their reduced sensitivity to the sedating effects of clozapine, compared with wildtype (WT) littermates, parallels the unexplained clinical observation that schizophrenia patients display a markedly heightened tolerance to antipsychotic side effects compared to healthy controls. Our preliminary studies reveal that a nearly 70% loss serotonin 2A receptor (5HT2AR) binding in the prefrontal cortex (PFC) of Egr3-/- mice appears to be the mechanism underlying this effect. Since schizophrenia patients also show a decreased expression of cortical 5HT2ARs, this suggests that regulation of 5HT2ARs may be a mechanism through which Egr3 influences schizophrenia risk. The goal of the current proposal is to fully characterize the anatomic localization and molecular mechanism of 5HT2AR regulation by Egr3, and to establish which of the Egr3-/- schizophrenia-like behavioral abnormalities are mediated by 5HT2AR deficiency. In Aim 1 we will use immunohistochemistry and in situ hybridization to anatomically define 5HT2AR expression in Egr3-/- mice. In Aim 2 we will use quantitative RT-PCR to determine the ability of environmental stress to modulate the regulation of Htr2a by Egr3. We will conduct chromatin immunoprecipitation and luciferase reporter assays to test the hypothesis that Egr3 regulates Htr2a expression through promoter binding. Aim 3 proposes to use virus-mediated overexpression of 5HT2AR to "rescue" the schizophrenia-like phenotypes of Egr3-/- mice, testing the hypothesis that the 5HT2AR-deficiency mediates these abnormalities. Identification of mechanisms by which Egr3 regulates another schizophrenia susceptibility gene will enhance our understanding of how numerous candidate genes may act in a biological pathway to influence risk for schizophrenia. Verification of such a pathway should elucidate targets for development of novel treatments for this devastating disorder. PUBLIC HEALTH RELEVANCE: The proposed studies are designed to reveal how two different proteins involved in schizophrenia susceptibility and treatment may interact to mediate the effect of environment on risk for this severe mental illness. This research has the potential t elucidate a cause of schizophrenia and to reveal early environmental interventions that could reduce the chances of developing schizophrenia, a debilitating psychiatric illness that afflicts 1% of the population worldwide.