The Role of STEP in Schizophrenia

STEP 在精神分裂症中的作用

• 批准号: 8230489
• 负责人: Paul J Lombroso
• 金额: $ 37.31万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8230489
• 关键词: Acute; Animal Model; Antipsychotic Agents; Attenuated; Behavior; Brain; C57BL/6 Mouse; Chronic; Clozapine; Cognition; Cognitive deficits; Corpus striatum structure; Cyclic AMP-Dependent Protein Kinases; DRD2 gene; Data; Disease; Dopamine; ErbB4 gene; Exocytosis; Family; Functional disorder; Genetic; Glutamate Receptor; Glutamates; Goals; Hallucinogens; Haloperidol; Impaired cognition; Knockout Mice; Laboratories; Lead; Link; Locomotion; MAPK3 gene; Mediating; Membrane; Membrane Proteins; Memory impairment; Modeling; Molecular; Motor Activity; Mus; NR1 gene; NRG1 gene; Neuregulins; Neurons; Pathway interactions; Patients; Persons; Pharmaceutical Preparations; Phencyclidine; Phosphorylation; Phosphorylation Site; Phosphotransferases; Play; Prefrontal Cortex; Process; Protein Tyrosine Phosphatase; Radial; Research; Role; Sampling; Schizophrenia; Signal Pathway; Signal Transduction; Slice; Surface; Symptoms; Synapses; Techniques; Testing; Therapeutic Agents; Tissues; Ubiquitin; Ubiquitination; Water; Work; arm; base; cingulate cortex; cohort; density; human FRAP1 protein; inhibitor/antagonist; mind control; multicatalytic endopeptidase complex; novel; object recognition; phosphatase inhibitor; prepulse inhibition; prevent; public health relevance; receptor; receptor internalization; trafficking; treatment effect

DESCRIPTION (provided by applicant): Striatal-Enriched tyrosine Phosphatase 61 (STEP61) is targeted to synaptic compartments and induces glutamate receptor internalization. We recently discovered that STEP61 is elevated in cingulate cortex of persons with schizophrenia (SZ). Our preliminary findings suggest that the increase of STEP61 results in internalization of glutamate receptors, a model consistent with the glutamate hypothesis of SZ. We also propose that the beneficial effects of antipsychotic medications are mediated through STEP61. The overall goals of this proposal are to define the mechanisms by which STEP61 mediates the loss of glutamate receptors in SZ, as well as its role in the beneficial effects of neuroleptics. In Aim 1, we will increase our samples of SZ cingulate cortex and include dorsolateral PFC. Our prediction is that STEP61 will again be elevated. We will determine the molecular mechanism by which this occurs. STEP61 is normally ubiquitinated and degraded by the proteasome. We propose that this process is disrupted in SZ. PKA phosphorylation of STEP61 is one signal that is necessary for the ubiquitination of STEP61. In the absence of PKA-phosphorylation, STEP61 is no longer ubiquitinated and degraded. We hypothesize, however, that additional kinases are required, and will identify these kinases and their phosphorylation sites in STEP61. Aim 1 will also test the hypothesis that the beneficial effects of neuroleptics are mediated through STEP61. We predict that dopamine D2R antagonists activate PKA, leading to the phosphorylation and inactivation of STEP61. Inactivation of STEP61 promotes trafficking of NMDAR to neuronal membranes. Aim 1 is significant as it explains aspects of the glutamate hypothesis of SZ as well as how neuroleptics function to ameliorate symptoms. Aim 2 will test our hypothesis in an animal model of SZ (NRG1 mice). NRG1 mice have decreased functional NMDARs on neuronal surfaces. Our hypothesis is that the loss of these receptors is mediated by activation of STEP61. We will first test our hypothesis by stimulating neuronal cultures and slices derived from WT and STEP KO mice with NRG1. Our prediction is that the absence of STEP61 will prevent NRG1-induced internalization of NMDARs. We will also test our hypothesis by crossing NRG1 with STEP KO mice. We predict that progeny null for STEP will rescue the loss of NMDARs from neuronal membranes. STEP KO mice have elevated levels of NMDARs and AMPARs on neuronal membranes. Aim 3 will test the hypothesis that these mice are less sensitive to the effects of psychotomimetic agents. Preliminary data indicate that this is the case: STEP KO mice are less sensitive to the acute effects of PCP on locomotor activity, as well as the subchronic effects of PCP on cognition. We have developed a STEP inhibitor called LDN-33960, and have shown that this compound reduces the acute effects of PCP on locomotor activity. We will test if this compound also reduces the cognitive deficits induced by PCP. Ultimately, our work has the potential of discovering a new family of therapeutic agents for SZ. PUBLIC HEALTH RELEVANCE: This R01 proposes a new hypothesis in the field of Schizophrenia Research: it implicates STriatal-Enriched tyrosine Phosphatase (STEP) in the pathophysiology of this devastating disease through STEP's ability to promote NMDAR internalization. STEP KO mice are less sensitive to the psychotomimetic effects of the noncompetitive NMDAR antagonist, PCP, and proof-of-concept studies demonstrate that a STEP inhibitor we have developed reduces the effects of PCP in WT mice. The proposed studies have the potential of making a major advance in the field as we will clarify how neuroleptics function, and we will also determine how the neuregulin/ErbB4 pathway, which has been implicated in the disease in genetic studies of schizophrenia, exerts its effects through STEP.

描述（由申请人提供）：纹状体富集酪氨酸磷酸酶61（STEP 61）靶向突触区室并诱导谷氨酸受体内化。我们最近发现，STEP 61在精神分裂症患者（SZ）的扣带皮层中升高。我们的初步研究结果表明，STEP 61的增加导致谷氨酸受体的内化，这一模型与SZ的谷氨酸假说一致。我们还提出，抗精神病药物的有益作用是通过STEP 61介导的。该提案的总体目标是确定STEP 61介导SZ中谷氨酸受体丢失的机制，以及其在神经阻滞剂的有益作用中的作用。 在目标1中，我们将增加SZ扣带皮层的样本，并包括背外侧PFC。我们的预测是STEP 61将再次升高。我们将确定这种情况发生的分子机制。STEP 61通常被蛋白酶体泛素化和降解。我们建议，这一过程在深圳中断。STEP 61的PKA磷酸化是STEP 61泛素化所必需的信号之一。在没有PKA磷酸化的情况下，STEP 61不再被泛素化和降解。然而，我们假设需要额外的激酶，并将在STEP 61中鉴定这些激酶及其磷酸化位点。目的1还将检验神经阻滞剂的有益作用是通过STEP 61介导的假设。我们预测多巴胺D2 R拮抗剂激活PKA，导致STEP 61的磷酸化和失活。STEP 61的失活促进NMDAR向神经元膜的运输。目的1是有意义的，因为它解释了SZ的谷氨酸假说的各个方面，以及神经阻滞剂如何发挥作用来改善症状。 目的2将在SZ动物模型（NRG 1小鼠）中验证我们的假设。NRG 1小鼠神经元表面的功能性NMDAR减少。我们的假设是这些受体的丢失是由STEP 61的激活介导的。我们将首先通过用NRG 1刺激来自WT和STEP KO小鼠的神经元培养物和切片来测试我们的假设。我们的预测是，STEP 61的缺失将阻止NRG 1诱导的NMDAR内化。我们还将通过将NRG 1与STEP KO小鼠杂交来验证我们的假设。我们预测，后代空的STEP将挽救损失的NMDAR从神经元膜。 STEP KO小鼠在神经元膜上具有升高水平的NMDAR和AMPAR。目的3将检验这些小鼠对拟精神病药物的作用不太敏感的假设。初步数据表明，情况确实如此：STEP KO小鼠对五氯苯酚对自发活动的急性影响以及五氯苯酚对认知的亚慢性影响不太敏感。我们已经开发了一种称为LDN-33960的STEP抑制剂，并表明该化合物可降低PCP对运动活性的急性影响。我们将测试这种化合物是否也能减少PCP引起的认知障碍。最终，我们的工作有可能为SZ发现一个新的治疗药物家族。 公共卫生相关性：该R 01在精神分裂症研究领域提出了一个新的假设：它通过STEP促进NMDAR内化的能力，暗示了这种毁灭性疾病的病理生理学中的富含酪氨酸的酪氨酸磷酸酶（STEP）。STEP KO小鼠对非竞争性NMDAR拮抗剂PCP的拟精神病作用不太敏感，概念验证研究表明，我们开发的STEP抑制剂可降低WT小鼠中PCP的作用。拟议的研究有可能在该领域取得重大进展，因为我们将阐明神经阻滞剂的功能，我们还将确定神经调节素/ErbB 4通路如何通过STEP发挥作用，该通路在精神分裂症的遗传研究中与疾病有关。