Role of brain specific tyrosine phophatase, STEP in neuroprotection and death

脑特异性酪氨酸磷酸酶 STEP 在神经保护和死亡中的作用

• 批准号: 8049000
• 负责人: Surojit Paul
• 金额: $ 32.16万
• 依托单位: UNIVERSITY OF NEW MEXICO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8049000
• 关键词: Animal Model; Attenuated; Back; Basal Ganglia; Binding; Biochemical; Brain; Calcium; Cell Culture System; Cell Death; Cell Survival; Cell membrane; Cessation of life; Cleaved cell; Corpus striatum structure; Cyclic AMP-Dependent Protein Kinases; Dopamine; Dopamine D1 Receptor; Event; Extracellular Signal Regulated Kinases; Glutamate Receptor; Glutamates; Goals; HIV; Hippocampus (Brain); Intervention; Ischemic Brain Injury; Ischemic Stroke; Lesion; Link; MAP Kinase Signaling Pathways; MAPK14 gene; Mediating; Methods; Middle Cerebral Artery Occlusion; Mitogen-Activated Protein Kinase Kinases; Molecular Biology Techniques; Molecular Target; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; NR1 NMDA receptor; NR2B NMDA receptor; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Neurotransmitters; Pathway interactions; Peptides; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiological; Play; Protein Dephosphorylation; Protein Tyrosine Phosphatase; Proteins; Proteolysis; Regulation; Research; Role; Serine; Severities; Signal Pathway; Specificity; Stroke; Structure; Testing; Time; Toxic effect; Tyrosine; attenuation; cell injury; excitotoxicity; extracellular; feeding; in vivo; loss of function; mitogen-activated protein kinase p38; mutant; nervous system disorder; neuron loss; neuroprotection; novel; novel therapeutic intervention; p38 MAPK Signaling Pathway; public health relevance; receptor; research study; response; stress activated protein kinase; therapeutic target; uptake

DESCRIPTION (provided by applicant): The long-term goal of this research is to determine the role of tyrosine phosphatases and dual-specificity phosphatases in neurological disorders of the basal ganglia and related structures. Our recent findings indicate that a striatal enriched tyrosine phosphatase, STEP, specifically expressed in the neurons of the cortex, hippocampus and striatum may participate in cell survival following an excitotoxic insult. The activity of STEP is itself regulated by the neurotransmitters dopamine and glutamate through phosphorylation and dephosphorylation of a critical serine residue within the kinase interacting motif or KIM domain. Glutamate/NMDA receptor mediated influx of Ca2+ activates STEP, whereas dopamine/D1 receptor mediated PKA activation leads to inactivation of STEP. The proposed study will now test whether STEP is activated through NR2B-NMDA receptors, a pool of NMDA receptor that is associated with glutamate excitotoxicity. It will also investigate whether active STEP in turn can down regulate or inhibit multiple interrelated pathways that are involved in glutamate/NMDA receptor-mediated cell death. We anticipate that active STEP, as part of a feed-back loop, can down regulate NR2B-NMDA receptor channel activity through tyrosine dephosphorylation of NR2B subunit, thereby inhibiting Ca2+ overload and subsequent cell damage. It can also inhibit the activation of the p38 MAP kinase signaling pathway that has been attributed to cell death in multiple neurodegenerative disorders. In this way STEP may promote cell survival following an initial insult. However depending upon the severity of the insult STEP may be proteolytically cleaved and eventually degraded, thereby facilitating activation of cell death pathways. The study will further investigate if a constitutively active form of STEP that cannot be proteolytically cleaved and can be delivered in vivo will be able to attenuate ischemic brain damage, where the involvement of glutamate excitotoxicity is well established. These studies will involve neuron culture experiments of glutamate toxicity and an animal model of ischemic stroke and will utilize biochemical, immunocytochemical and molecular biology techniques. The findings will help us to determine whether the tyrosine phosphatase STEP may be therapeutically beneficial and can be considered for the treatment of ischemic stroke and related neurological disorders. PUBLIC HEALTH RELEVANCE: The goal of the proposed study is to understand the role of a brain-enriched and neuron-specific tyrosine phosphatase, STEP, in neuronal cell death following an excitotoxic insult. The findings will help us to determine whether STEP can attenuate excitotoxic neuronal cell death and can be considered as a potential therapeutic target for the treatment of ischemic stroke and related neurological disorders.

描述(申请人提供)：这项研究的长期目标是确定酪氨酸磷酸酶和双特异性磷酸酶在基底节和相关结构的神经疾病中的作用。我们最近的发现表明，纹状体丰富的酪氨酸磷酸酶，STEP，在皮质、海马区和纹状体的神经元中特异表达，可能参与了兴奋性损伤后的细胞生存。STEP的活性本身由神经递质多巴胺和谷氨酸通过磷酸化和去磷酸化的关键丝氨酸残基相互作用的基序或KIM结构域来调节。谷氨酸/NMDA受体介导的Ca~(2+)内流激活STEP，而多巴胺/D_1受体介导的PKA激活导致STEP失活。这项拟议的研究现在将测试STEP是否通过NR2B-NMDA受体激活，NMDA受体是一种与谷氨酸兴奋毒性相关的NMDA受体池。它还将研究活性步骤是否反过来可以下调或抑制参与谷氨酸/NMDA受体介导的细胞死亡的多个相互关联的途径。我们预计，作为反馈环的一部分，该活性步骤可以通过NR2B亚单位的酪氨酸去磷酸化下调NR2B-NMDA受体通道的活性，从而抑制钙超载和随后的细胞损伤。它还可以抑制p38 MAP激酶信号通路的激活，该信号通路已被归因于多种神经退行性疾病中的细胞死亡。通过这种方式，STEP可能会在最初的侮辱后促进细胞存活。然而，根据损伤的严重程度，步骤可能被蛋白分解并最终降解，从而促进细胞死亡途径的激活。这项研究将进一步调查一种不能被蛋白质分解并可以在体内传递的结构性活性形式的STEP是否能够减轻缺血性脑损伤，在这种情况下，谷氨酸的兴奋毒性已经得到了很好的证实。这些研究将涉及谷氨酸毒性的神经元培养实验和缺血性中风的动物模型，并将利用生化、免疫细胞化学和分子生物学技术。这些发现将帮助我们确定酪氨酸磷酸酶步骤是否对治疗有益，并可被考虑用于治疗缺血性中风和相关的神经疾病。 公共卫生相关性：这项拟议研究的目标是了解一种富含大脑和神经元特异性的酪氨酸磷酸酶STEP在兴奋毒性侮辱后神经细胞死亡中的作用。这一发现将有助于我们确定STEP是否能减轻兴奋性神经细胞死亡，并可被视为治疗缺血性中风和相关神经疾病的潜在治疗靶点。