Role of the subthalamic nucleus and TrkB following dopamine loss

多巴胺丢失后丘脑底核和 TrkB 的作用

• 批准号: 8923940
• 负责人: Charles Kenneth Meshul
• 金额: --
• 依托单位: PORTLAND VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8923940
• 关键词: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Acute; Address; Affect; Age; Agonist; Animal Disease Models; Animal Model; Animals; Area; Bilateral; Brain; Caring; Cell Death; Cells; Clinical Research; Corpus striatum structure; Cre-LoxP; Deep Brain Stimulation; Disease; Dopamine; Education; Fiber; Frequencies; Funding; Gene Deletion; Gene Targeting; General Population; Genes; Glutamates; Goals; Green Fluorescent Proteins; Human; Incidence; Infusion procedures; Intervention; Investigation; Label; Lesion; Measures; Medical center; Motor; Movement Disorders; Mus; Nerve; Neurons; Neurotoxins; Oxidopamine; Parkinson Disease; Population; Receptor Protein-Tyrosine Kinases; Research; Research Priority; Research Project Grants; Role; Structure of subthalamic nucleus; Substantia nigra structure; Synaptic Vesicles; Technology; Toxin; Tyrosine 3-Monooxygenase; Veterans; aged; dopaminergic neuron; excitotoxicity; extracellular; immunoreactivity; motor deficit; motor function improvement; neuroprotection; neurorestoration; nigrostriatal pathway; pars compacta; public health relevance; receptor; recombinase; restoration; uptake; vesicular glutamate transporter 2

 DESCRIPTION (provided by applicant): Following the loss of nigrostriatal dopamine (DA), there is an increase in activity of glutamate neurons within the subthalamic nucleus (STN). In animal models and in humans with Parkinson's disease (PD), both a lesion or high frequency stimulation/deep brain stimulation (DBS) of the STN results in improvement in motor function and provides symptomatic relief. However, both DBS and a lesion of the STN could be affecting the fibers of passage. Direct inactivation of the STN neurons without affecting the fibers of passage could answer this concern. Since STN neurons utilize the vesicular glutamate transporter 2 (VGLUT2) for uptake of glutamate into synaptic vesicles, deletion of this gene would selectively inactivate those STN glutamate neurons and block glutamate release. Using the Cre/loxP recombinase gene technology where a specific gene can be silenced, inactivation of the STN glutamate neurons can be achieved through deleting a targeted gene in the specific brain area by injecting AAV-Cre to mice that are floxed for Vglut2 (Vglut2flox/flox). To determine if deletion of the Vglut2 gene in the STN can be neuroprotective against DA terminal and cell loss using the neurotoxin, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), we find that a unilateral infusion of AAV-Cre-GFP (green fluorescent protein) into the STN inactivated approximately 80% of those STN glutamate neurons, as determined by GFP labeling of STN neurons. As measured by tyrosine hydroxylase (TH) immunoreactivity, this resulted in a bilateral protection from the loss of DA terminals in the striatum and DA neurons in the substantia nigra pars compacta (SNpc) following progressive administration of MPTP compared to the wildtype mice treated with the toxin. There was a 35% decrease in activated tyrosine kinase receptor B (TrkB) within the substantia nigra (SN) following MPTP compared to the vehicle treated group. If VGLUT2 deletion occurred following the initiation of MPTP treatment (i.e, neurointervention), we find striatal nerve terminals recovered to nearly 80% of the vehicle treated group. Since MPTP results in a decrease in activated TrkB in the SN, deletion of the Vglut2 gene within the STN, which we found resulted in a decrease in extracellular glutamate in the SN, would allow activated TrkB in the SN to return to control levels and protect the SNpc neurons. To address a possible mechanism of this protection, we find that systemic administration of the TrkB agonist, 7,8-dihydroxyflavone, 2 weeks after the initiation of MPTP treatment (i.e., neurointervention) resulted in a blockade of any further loss of TH within the striatum due to continued MPTP treatment. The overall goal of this project is to determine whether deletion of the Vglut2 gene within the STN initiated following (i.e., restoration) either progressive administration of MPTP or intrastriatal infusion of 6-hydroxydopamine (6-OHDA) can reverse the loss of DA within the nigrostriatal pathway in both young and aged mice. We will also determine the role of TrkB in blocking or reversing the DA depletion due to MPTP. The specific aims of this proposal are to: 1.) determine if deletion of the Vglut2 gene within the STN initiated 4 weeks after progressive MPTP administration can reverse the loss of DA markers in the striatum/SN and motor function in both young and aged mice, 2.) determine if deletion of the Vglut2 gene within the STN initiated 12 days following infusion of 6-OHDA into the dorsolateral striatum can reverse the loss of DA markers in the striatum/SN and motor function in both young and aged mice, and 3.) determine if the neuroprotection from MPTP following deletion of the Vglut2 gene within the STN is due to maintained levels of activated TrkB in the SN by daily infusion of a TrkB agonist into the SN.

 描述（由申请人提供）： 在骨纹状体多巴胺（DA）丧失之后，丘脑核核心（STN）内谷氨酸神经元的活性增加。在动物模型和患有帕金森氏病（PD）的人类中，无论是病变还是高频刺激/深脑刺激（DBS），可以改善运动功能并提供症状缓解。但是，DBS和STN病变都可能影响通道的纤维。直接失活STN神经元而不影响通道纤维可以回答这种关注。由于STN神经元利用囊泡谷氨酸转运蛋白2（VGLUT2）将谷氨酸摄取到突触蔬菜中，因此该基因的缺失将有选择地使这些STN谷氨酸神经元和阻断谷氨酸释放。使用CRE/LOXP重组酶基因技术可以沉默，可以通过在特定脑区域中删除特定脑区域的靶向基因来通过将AAV-CRE注射到flox for fin for vglut2flox/flox（vglut2flox/flox）中来实现STN谷氨酸神经元的失活。为了确定STN中VGLUT2基因的缺失是否可以使用神经毒素对DA末端和细胞损失具有神经保护作用通过STN神经元的GFP标记确定的谷氨酸神经元。通过酪氨酸羟化酶（Th）免疫反应性测量，这导致双边保护与与毒素治疗的Wildtype小鼠相比，在逐渐施用MPTP之后，NIGRA PARS CMPSTA（SNPC）中纹状体和DA神经元中的DA末端损失。与媒介物治疗组相比，MPTP之后，在MPTP之后，活性酪氨酸激酶受体B（TRKB）降低了35％。如果在MPTP治疗计划（即神经介入）的倡议后发生VGLUT2缺失，我们会发现回收到近80％的车辆治疗组的纹状体神经末端。由于MPTP导致SN中激活的TRKB降低，因此STN中VGLUT2基因的缺失（我们发现这会导致SN中的细胞外谷氨酸的降低）允许SN中的激活TRKB返回到控制水平并保护SNPC神经元。为了解决这种保护的可能机制，我们发现，在MPTP治疗计划（即神经介入）倡议后2周，TRKB激动剂的系统给药7,8-二羟基氟氟氟氟氟氟氟此动力，导致了由于MPTP治疗而导致的纹状体内的任何进一步损失。该项目的总体目标是确定在启动的stn中删除vglut2基因是以下（即恢复）MPTP或 纹状体内输注6-羟基多巴胺（6-OHDA）可以扭转年轻小鼠和老年小鼠的黑质纹状体途径内DA的损失。我们还将确定TRKB在阻止或逆转MPTP引起的DA部署中的作用。该提案的具体目的是：1。）确定在进行性MPTP施用后4周内启动的STN中的vglut2基因是否是否会逆转纹状体/SN和运动功能在年轻小鼠和年龄小鼠中的DA标记的损失，2。）2。）确定在STN内部损失12天后的striate inter inter inter in the striation in 6-hodirial in 6-impy ins in 6-impy ins in de te sTN的损失是否属于6--hoh ins in the STR的损失。纹状体/SN和运动功能在年轻小鼠和年龄小鼠中的DA标记，以及3.）确定STN中vglut2基因删除后MPTP的神经保护是否是否是由于每天通过将TRKB激动剂输注到SN中的SN中的trkb的水平。