GSK-3 beta, a mediator of ethanol neurotoxicity

GSK-3 beta，乙醇神经毒性的介质

• 批准号: 6984239
• 负责人: JIA LUO
• 金额: $ 26.55万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6984239
• 关键词: apoptosis; binding proteins; cell growth regulation; cell migration; developmental neurobiology; embryo /fetus toxicology; enzyme activity; enzyme induction /repression; enzyme inhibitors; ethanol; gene expression; immature animal; laboratory rat; neurons; neuroprotectants; neurotoxicology; phosphorylation; protein localization; protein structure function; serine threonine protein kinase; tissue /cell culture

DESCRIPTION (provided by applicant): Two of the most striking effects of ethanol exposure during development are the disruption of neuronal migration and the deletion of neurons in certain areas of the central nervous system (CMS). The cellular/ molecular mechanisms underlying these damages remain unclear. Glycogen synthase kinase-3/beta (GSK3beta) is predominantly expressed in neurons in the developing CMS, and emerges as a critical signaling component regulating diverse events of neuronal development, such as neuronal migration and proliferation/survival. It has also been implicated in abnormalities in the adult brain, such as neurodegenerative diseases. The activity of GSK3beta is regulated by phoshorylation and subcellular localization. GSK3beta is activated by various cellular stresses including endoplasmic reticulum (ER) stress. We have demonstrated that ethanol exposure induces ER stress and significantly alters the phosphorylation state of a GSK3beta in vitro and in vivo event at modest concentrations (50-100 mg/dl); blocking GSK3beta activation mitigates ethanol-induced neuronal death. Although ethanol alone at relatively low concentrations does not cause neuronal death, it greatly potentiates apoptosis caused by various exogenous insults which also activate GSK3beta. In contrast, ethanol does not affect cell death induced by pro-apoptotic signals which are independent of GSK3beta. We hypothesize that GSK3beta is a critical mediator of ethanol neurotoxicity. In this proposal, we will characterize the effect of ethanol on phosphorylation/activity, subcellular localization and expression of GSK3beta in the developing neurons using various model systems (cultured neurons, organotypic slice culture of rat cerebellum and the developing cerebellum). Subsequently, we will determine the role of GSK3beta in ethanol-induced cell cycle arrest, apoptosis, inhibition of neurite outgrowth and aberrant migration patterns; we will determine whether blocking GSK3beta activation by selective inhibitors or over- expression of dominant negative GSK3beta (DN-GSK3beta) or GSK3beta binding protein (GBP) provides neuroprotection against ethanol-induced damage. In addition, we will investigate the role of Chop (GADD153), another ER stress responsive factor, in ethanol-induced neuronal damages. Futhermore, we will elucidate the mechanisms underlying GSK3beta activation; we will systematically investigate up-stream signaling of GSK3beta and the contribution of ER stress-responsive components, such as protein phosphatase 2A, to ethanol-induced GSK3beta activation. Finally, we will investigate whether ethanol-induced sensitization or potentiation to apoptosis caused by other insults is dependent on GSK3beta we will determine whether over- expression of DN- GSK3beta and GBP abolishes ethanol-induced potentiation to neuronal death triggered by other pro-apoptotic stimuli. As a unit, these experiments will explore a novel mechanism underlying ethanol- induced damage to the CMS using in vitro and in vivo model systems. The systematical study may establish GSK3beta as a potential therapeutic target for the treatment of alcohol neurotoxicity

描述（由申请人提供）：发育过程中乙醇暴露的两个最引人注目的作用是神经元迁移的中断和中枢神经系统某些区域（CMS）中神经元的删除。这些损伤背后的细胞/分子机制尚不清楚。糖原合酶激酶-3/β（GSK3BETA）主要在发育中的CMS中的神经元中表达，并且作为调节神经元发育的多种事件的关键信号成分，例如神经元迁移和增殖/生存。它也与成人大脑的异常有关，例如神经退行性疾病。 GSK3BETA的活性受chorylation和亚细胞定位的调节。 GSK3BETA通过包括内质网（ER）应力在内的各种细胞应激激活。我们已经证明，乙醇暴露会诱导ER应激，并显着改变GSK3BETA的体外和体内事件的磷酸化状态，以适度的浓度（50-100 mg/dl）；阻断GSK3BETA激活可减轻乙醇诱导的神经元死亡。尽管仅乙醇在相对较低的浓度下并不会引起神经元死亡，但它极大地增强了由各种外源性损伤引起的凋亡，这也激活了GSK3BETA。相反，乙醇不影响与GSK3BETA无关的凋亡信号引起的细胞死亡。我们假设GSK3Beta是乙醇神经毒性的关键介体。在此提案中，我们将使用各种模型系统（培养的神经元，大鼠小脑的器官切片培养物和发育的小脑）在发育中的神经元中在发育中的神经元中GSK3BETA的磷酸化/活性，亚细胞定位和表达的影响。随后，我们将确定GSK3BETA在乙醇诱导的细胞周期停滞，凋亡，神经突生长的抑制和异常迁移模式中的作用；我们将确定是否通过选择性抑制剂阻断GSK3BETA激活或过度表达显性阴性GSK3BETA（DN-GSK3BETA）或GSK3BETA结合蛋白（GBP）可提供针对乙醇诱导损伤的神经保护作用。此外，我们将研究另一个ER应力响应因子CHOP（GADD153）在乙醇诱导的神经元损伤中的作用。 futhermore，我们将阐明GSK3BETA激活的基础机制；我们将系统地研究GSK3BETA的上流信号传导以及ER应力响应成分（例如蛋白质磷酸酶2a）对乙醇诱导的GSK3BETA激活的贡献。最后，我们将研究乙醇引起的对其他侮辱引起的对凋亡的敏感性或增强是否取决于GSK3BETA，我们将确定DN-GSK3BETA和GBP的过度表达是否废除了乙醇诱导的对神经元死亡的增强，从而触发了其他亲脑刺激触发的神经元死亡。作为一个单位，这些实验将探索使用体外和体内模型系统对乙醇诱导的CMS造成的新机制。系统的研究可能会建立GSK3BETA作为治疗酒精神经毒性的潜在治疗靶点