Pathophysiologic roles of alpha-synuclein at the synapse

α-突触核蛋白在突触中的病理生理作用

• 批准号: 9765861
• 负责人: Subhojit Roy
• 金额: $ 53.53万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9765861
• 关键词: Advocate; Affect; Alanine; Alzheimer' s Disease; American; Animal Model; Area; Attenuated; Binding; Biological Assay; Cell model; Consensus; Data; Dementia; Disease; Event; Family; Genomics; Goals; Impaired cognition; Knowledge; Lead; Lewy Body Dementia; Maps; Mediating; Microscopy; Modeling; Molecular; Mutagenesis; Mutation; Nerve Degeneration; Neurons; Optics; PHluorin; Pathologic; Pathology; Physiological; Play; Process; Proteins; Recycling; Reporting; Research Personnel; Role; Series; Shapes; Synapses; Synapsins; Synaptic Vesicles; System; Testing; Toxic effect; Vesicle; Work; alpha synuclein; attenuation; experimental study; in vivo; in vivo evaluation; monomer; mutant; neocortical; neurotransmission; neurotransmitter release; novel; predictive modeling; presynaptic; synuclein; synucleinopathy; tool; trafficking; ward

The overall goal of this proposal is to clarify mechanistic pathobiological events underlying Lewy body (LB) dementias – a dementing illness with cognitive impairment that affects more than a million Americans. An established molecular player in LB dementia is the small presynaptic protein α-synuclein. Amongst a plethora of incriminating evidence, genomic multiplications and mutations of α-synuclein are seen in families harboring these diseases; and it has been long recognized that understanding the mechanistic events that lead to α-synuclein-mediated toxicity in LB dementia is of utmost importance. For over a decade, a primary focus in the field has been to decipher the normal function of α-synuclein, with the ultimate goal of understanding transition to pathologic states. However, despite considerable effort, the precise mechanisms underlying the normal function of α-synuclein, and early triggers leading to pathologic aggregation remain elusive. The basis of our proposal is a series of pilot experiments, where we uncovered novel roles for two functional partners of α-synuclein, and we hypothesize that abnormalities in these associations are the initial pathologic triggers for LB dementias. Previous work from us and others has helped shape a consensus that α-synuclein is a physiologic attenuator of neurotransmitter release, though underlying mechanistic events are unclear. In these previous studies, we proposed a model where α-syn organizes into higher-order multimers that physiologically tether synaptic vesicles (SVs) – leading to a diminution in SV-mobilization, SV-recycling, and consequently, neurotransmitter release. In new pilot experiments, we discovered novel roles for two other presynaptic proteins – VAMP2 and synapsin – in helping α-synuclein attenuate neurotransmission. Eventually, our data led us to a working model where synapsin and VAMP2 play sequential roles in executing α-synuclein function. Tenets of this model will be tested in Aims 1/2. Additionally, an emerging idea in the field is that disruption of physiologic associations might allow free α-synuclein monomers to aggregate – triggering pathology – and that this might be one of the earliest pathologic events in disease; however, in vivo evidence is lacking. Leveraging our discoveries on functional α-synuclein partners, Aims 2/3 will ask if a disruption of these associations might also accelerate pathology in cellular and animal models of LB dementias. Our aims are: Aim #1: Identify the role of VAMP2 in α-synuclein mediated synaptic attenuation. Aim #2: Identify the role of synapsin in α-synuclein mediated synaptic attenuation and pathology. Aim #3: Test the hypothesis that disrupting physiologic associations can trigger α-synuclein pathology in vivo. Upon completion, our studies should reveal vital clues into the normal function of α-synuclein, as well as events that trigger dementia and cognitive impairment in these devastating illnesses.

该提案的总体目标是阐明路易机构（LB）痴呆症的机理病理生物学事件 - 一种具有认知障碍的痴呆疾病，影响了超过一百万的美国人。在LB痴呆中建立的分子参与者是小的突触前蛋白α-突触核蛋白。在大量有罪的证据中，在拥有这些疾病的家庭中可以看到α-突触核蛋白的基因组繁殖和突变。长期以来，人们已经认识到，了解导致LB痴呆症中α-突触核蛋白介导的毒性的机械事件至关重要。十多年来，该领域的主要重点一直是破译α-核蛋白的正常功能，其最终目标是了解过渡到病理状态。然而，尽管考虑了良好的努力，但α-突触核蛋白正常功能的确切机制以及导致病理聚集的早期触发因素仍然难以捉摸。我们的建议的基础是一系列试验实验，我们发现了两个功能性伴侣的新作用，并假设这些关联中的异常是LB痴呆症的初始病理触发器。我们和其他人的先前工作有助于达成共识，即α-突触核蛋白是神经递质释放的生理减毒剂，尽管尚不清楚潜在的机械事件。在这些先前的研究中，我们提出了一个模型，其中α-Syn组织了较高的多聚体，以绑扎突触蔬菜（SVS），从而导致了SV-动作，SV复位，SV复位的维度，因此，神经递质释放。在新的试点实验中，我们发现了另外两种突触前蛋白-VAMP2和Synapsin的新作用，可帮助α-突触核蛋白减轻神经传递。最终，我们的数据导致我们进入了一个工作模型，其中突触素和VAMP2在执行α-突触核蛋白函数中扮演顺序作用。该模型的原则将在目标1/2中进行测试。此外，该领域的一个新想法是，生理关联的破坏可能会使自由α-突触核蛋白单体可以汇总 - 触发病理 - 这可能是疾病中最早的病理事件之一。但是，缺乏体内证据。利用我们对功能性α-突触核蛋白伴侣的发现，目标2/3会询问这些关联的破坏是否也可能加速LB痴呆症的细胞和动物模型。我们的目标是：目标＃1：确定VAMP2在α-突触核蛋白介导的突触衰减中的作用。 AIM＃2：确定突触素在α-突触核蛋白介导的突触衰减和病理学中的作用。 AIM＃3：检验以下假设：破坏生理关联可以在体内触发α-核蛋白病理学。完成后，我们的研究应揭示出α-突触核蛋白的正常功能的重要线索，以及在这些毁灭性疾病中引发痴呆症和认知障碍的事件。