De Luca Chiara Maria Giulia, Elia Antonio Emanuele, Portaleone Sara Maria, Cazzaniga Federico Angelo, Rossi Martina, Bistaffa Edoardo, De Cecco Elena, Narkiewicz Joanna, Salzano Giulia, Carletta Olga, Romito Luigi, Devigili Grazia, Soliveri Paola, Tiraboschi Pietro, Legname Giuseppe, Tagliavini Fabrizio, Eleopra Roberto, Giaccone Giorgio, Moda Fabio
1Fondazione IRCCS Istituto Neurologico Carlo Besta, Unit of Neurology 5 and Neuropathology, Milan, Italy.
2Fondazione IRCCS Istituto Neurologico Carlo Besta, Unit of Neurology I - Parkinson and Movement Disorders Unit, Milan, Italy.
Transl Neurodegener. 2019 Aug 8;8:24. doi: 10.1186/s40035-019-0164-x. eCollection 2019.
Parkinson's disease (PD) is a neurodegenerative disorder whose diagnosis is often challenging because symptoms may overlap with neurodegenerative parkinsonisms. PD is characterized by intraneuronal accumulation of abnormal α-synuclein in brainstem while neurodegenerative parkinsonisms might be associated with accumulation of either α-synuclein, as in the case of Multiple System Atrophy (MSA) or tau, as in the case of Corticobasal Degeneration (CBD) and Progressive Supranuclear Palsy (PSP), in other disease-specific brain regions. Definite diagnosis of all these diseases can be formulated only neuropathologically by detection and localization of α-synuclein or tau aggregates in the brain. Compelling evidence suggests that trace-amount of these proteins can appear in peripheral tissues, including receptor neurons of the olfactory mucosa (OM).
We have set and standardized the experimental conditions to extend the ultrasensitive Real Time Quaking Induced Conversion (RT-QuIC) assay for OM analysis. In particular, by using human recombinant α-synuclein as substrate of reaction, we have assessed the ability of OM collected from patients with clinical diagnoses of PD and MSA to induce α-synuclein aggregation, and compared their seeding ability to that of OM samples collected from patients with clinical diagnoses of CBD and PSP.
Our results showed that a significant percentage of MSA and PD samples induced α-synuclein aggregation with high efficiency, but also few samples of patients with the clinical diagnosis of CBD and PSP caused the same effect. Notably, the final RT-QuIC aggregates obtained from MSA and PD samples owned peculiar biochemical and morphological features potentially enabling their discrimination.
Our study provide the proof-of-concept that olfactory mucosa samples collected from patients with PD and MSA possess important seeding activities for α-synuclein. Additional studies are required for (i) estimating sensitivity and specificity of the technique and for (ii) evaluating its application for the diagnosis of PD and neurodegenerative parkinsonisms. RT-QuIC analyses of OM and cerebrospinal fluid (CSF) can be combined with the aim of increasing the overall diagnostic accuracy of these diseases, especially in the early stages.
帕金森病（PD）是一种神经退行性疾病，其诊断往往具有挑战性，因为症状可能与神经退行性帕金森综合征重叠。PD的特征是脑干中异常α-突触核蛋白在神经元内积聚，而神经退行性帕金森综合征可能与α-突触核蛋白的积聚有关，如多系统萎缩（MSA）的情况，或与tau蛋白的积聚有关，如皮质基底节变性（CBD）和进行性核上性麻痹（PSP）的情况，这些蛋白在其他特定疾病的脑区积聚。所有这些疾病的明确诊断只能通过神经病理学方法，通过检测和定位脑中的α-突触核蛋白或tau蛋白聚集体来确定。有力证据表明，这些蛋白质的痕量可出现在外周组织中，包括嗅黏膜（OM）的受体神经元。
我们设定并标准化了实验条件，以扩展用于OM分析的超灵敏实时震颤诱导转化（RT-QuIC）检测方法。特别是，通过使用人重组α-突触核蛋白作为反应底物，我们评估了从临床诊断为PD和MSA的患者收集的OM诱导α-突触核蛋白聚集的能力，并将它们的种子接种能力与从临床诊断为CBD和PSP的患者收集的OM样本的种子接种能力进行了比较。
我们的结果表明，相当比例的MSA和PD样本能高效诱导α-突触核蛋白聚集，但临床诊断为CBD和PSP的患者的少数样本也产生了相同的效果。值得注意的是，从MSA和PD样本获得的最终RT-QuIC聚集体具有独特的生化和形态学特征，可能有助于对它们进行区分。
我们的研究提供了概念验证，即从PD和MSA患者收集的嗅黏膜样本对α-突触核蛋白具有重要的种子接种活性。需要进一步研究（i）评估该技术的敏感性和特异性，以及（ii）评估其在PD和神经退行性帕金森综合征诊断中的应用。对OM和脑脊液（CSF）进行RT-QuIC分析可以结合起来，以提高这些疾病的总体诊断准确性，特别是在早期阶段。
