Mechanism of 5HT2AR regulation by Egr3

描述（由申请人提供）：即刻早期基因早期生长反应3（EGR 3）与精神分裂症相关，在死后患者的大脑中表达水平降低。我们以前曾报道，Egr 3缺陷（-/-）小鼠显示出许多精神分裂症样的行为异常。此外，与野生型（WT）同窝仔相比，他们对氯氮平镇静作用的敏感性降低，这与无法解释的临床观察结果相平行，即与健康对照相比，精神分裂症患者对抗精神病药物副作用的耐受性明显提高。我们的初步研究表明，近70%的损失5-羟色胺2A受体（5 HT 2AR）结合在前额叶皮层（PFC）的Egr 3-/-小鼠似乎是这种效果的机制。由于精神分裂症患者也表现出皮质5 HT 2ARs表达的降低，这表明5 HT 2ARs的调节可能是Egr 3影响精神分裂症风险的机制。目前的建议的目标是充分表征的解剖定位和Egr 3的5 HT 2AR调节的分子机制，并建立Egr 3-/-精神分裂症样行为异常是由5 HT 2AR缺陷介导的。在目的1中，我们将使用免疫组织化学和原位杂交，以解剖学定义5 HT 2AR在Egr 3-/-小鼠的表达。在目的2中，我们将使用定量RT-PCR来确定环境胁迫调节Egr 3对Htr 2a的调节的能力。我们将进行染色质免疫沉淀和荧光素酶报告基因检测，以检验Egr 3通过启动子结合调节Htr 2a表达的假设。目的3提出使用病毒介导的5 HT 2AR过表达来“拯救”Egr 3-/-小鼠的精神分裂症样表型，测试5 HT 2AR缺陷介导这些异常的假设。Egr 3调节另一种精神分裂症易感基因的机制的鉴定将增强我们对许多候选基因如何在生物学途径中影响精神分裂症风险的理解。这种途径的验证应该阐明这种破坏性疾病的新治疗方法的发展目标。

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.