Exosomes and Neuroinflammation in Parkinsons Disease

描述（申请人提供）：近年来，神经炎症被认为是帕金森病（PD）的一个主要病理生理过程。在各种神经炎症触发因素中，蛋白质聚集已被证明是脑内小胶质细胞激活和随后的促炎细胞因子和趋化因子产生的主要病理触发因素，这反过来又有助于神经退行性过程的加速进展。此外，新出现的证据表明，聚集的致病蛋白，包括α-突触核蛋白（αSyn），被包装到外泌体中，外泌体通过非细胞自主过程将蛋白质聚集物从受影响的神经元传播到其他脑细胞，包括小胶质细胞，导致神经炎症反应加剧。尽管取得了这些进展，但αSyn聚集体和含αSyn外泌体刺激后小胶质细胞介导的神经炎症事件的细胞机制尚未明确。在研究PD模型中的激酶信号传导时，我们意外地发现，在已知的炎性原LPS刺激的几分钟内，主要的非受体酪氨酸激酶Fyn在初级小胶质细胞中迅速激活。有趣的是，Fyn激活会引发促炎反应，包括小胶质细胞释放细胞因子/趋化因子。此外，我们的初步研究结果显示，聚集的α - syn也诱导Fyn激酶和NLRP3炎症小体的快速激活。为了进一步扩展我们新颖的初步结果，我们将系统地追求以下具体目标：(i)研究αSyn聚集体和含αSyn聚集体的外泌体诱导炎症应激时，Fyn激酶的激活机制及其在调节小胶质细胞和星形胶质细胞NLRRP2/3炎性小体中的作用，确定Fyn在多巴胺能神经元细胞死亡中的促炎作用；（ii）在PD动物模型中αSyn聚集体和αSyn外泌体诱导的持续炎症反应中，确定Fyn在小胶质细胞和星形胶质细胞中上调的分子机制；（iii）确定Fyn在PD动物模型和死后PD脑组织中αSyn蛋白聚集过程中介导黑质纹状体多巴胺能系统的促炎症反应中的作用。生化，细胞和神经化学的方法将被用来实现这些特定的目标。综上所述，描述Fyn激酶在αSyn蛋白聚集诱导的小胶质细胞激活中的作用不仅将为PD神经退行性过程的进展提供新的机制见解，而且可能有助于将机制结果转化为PD的有效治疗方法。

DESCRIPTION (provided by applicant): Neuroinflammation has been implicated as a major pathophysiological process of Parkinson's disease (PD) in recent years. Among various neuroinflammatory triggers, protein aggregates have been shown to be a predominant pathological trigger for microglial activation and subsequent proinflammatory cytokine and chemokine production in the brain, which in turn con tributes to the accelerated progression of neurodegenerative processes. Also, emerging evidence indicates that aggregated pathogenic proteins, including α-synuclein (αSyn), are packaged into exosomes, which propagate protein aggregates from affected neurons to other brain cells, including microglial cells, through a non-cellular autonomous process, leading to a heightened neuroinflammatory response. Despite these advances, the cellular mechanisms underlying microglia-mediated neuroinflammatory events following stimulation with αSyn aggregates and αSyn-containing exosomes are yet to be defined. While studying kinase signaling in PD models, we unexpectedly discovered that the major non-receptor tyrosine kinase Fyn is rapidly activated in primary microglia within a few minutes of stimulation with the known inflammogen LPS. Interestingly, Fyn activation triggers proinflammatory responses, including cytokine/chemokine release from microglia. In addition, our preliminary findings revealed that aggregated αSyn also induced a rapid activation of Fyn kinase and the NLRP3 inflammasome. To further expand our novel preliminary results, we will systematically pursue the following specific aims: (i) to characterize the mechanism of Fyn kinase activation and its role in the regulation of NLRRP2/3 inflammasomes in microglia and astrocytes during inflammatory stress induced by αSyn aggregates and exosomes containing αSyn aggregates and to determine the proinflammatory role of Fyn in dopaminergic neuronal cell death, (ii) to define the molecular mechanisms underlying Fyn upregulation in microglia and astroglia during sustained inflammatory responses induced by αSyn aggregates and αSyn exosomes in animal models of PD, and (iii) to determine the role of Fyn in mediating the proinflammatory response in the nigrostriatal dopaminergic system during αSyn protein aggregation in animal models of PD as well as in postmortem PD brain tissues. Biochemical, cellular and neurochemical approaches will be used to achieve these specific aims. Taken together, delineating the role of Fyn kinase in αSyn protein aggregation-induced microglial activation will not only provide novel mechanistic insights into the progression of neurodegenerative processes in PD, but may also be useful for translating mechanistic outcomes into effective therapies for PD.