Kannarkat George T, Zack Rebecca, Skrinak R Tyler, Morley James F, Davila-Rivera Roseanne, Arezoumandan Sanaz, Dorfmann Katherine, Luk Kelvin, Wolk David A, Weintraub Daniel, Tropea Thomas F, Lee Edward B, Xie Sharon X, Chandrasekaran Ganesh, Lee Virginia M-Y, Irwin David, Akhtar Rizwan S, Chen-Plotkin Alice S
bioRxiv. 2024 May 8:2024.05.07.593056. doi: 10.1101/2024.05.07.593056.
Spread and aggregation of misfolded α-synuclein (aSyn) within the brain is the pathologic hallmark of Lewy body diseases (LBD), including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). While evidence exists for multiple aSyn protein conformations, often termed "strains" for their distinct biological properties, it is unclear whether PD and DLB result from aSyn strain differences, and biomarkers that differentiate PD and DLB are lacking. Moreover, while pathological forms of aSyn have been detected outside the brain ( in skin, gut, blood), the functional significance of these peripheral aSyn species is unclear. Here, we developed assays using monoclonal antibodies selective for two different aSyn species generated - termed Strain A and Strain B - and used them to evaluate human brain tissue, cerebrospinal fluid (CSF), and plasma, through immunohistochemistry, enzyme-linked immunoassay, and immunoblotting. Surprisingly, we found that plasma aSyn species detected by these antibodies differentiated individuals with PD vs. DLB in a discovery cohort (UPenn, n=235, AUC 0.83) and a multi-site replication cohort (Parkinson's Disease Biomarker Program, or PDBP, n=200, AUC 0.72). aSyn plasma species detected by the Strain A antibody also predicted rate of cognitive decline in PD. We found no evidence for aSyn strains in CSF, and ability to template aSyn fibrillization differed for species isolated from plasma vs. brain, and in PD vs. DLB. Taken together, our findings suggest that aSyn conformational differences may impact clinical presentation and cortical spread of pathological aSyn. Moreover, the enrichment of these aSyn strains in plasma implicates a non-central nervous system source.
错误折叠的α-突触核蛋白（aSyn）在脑内的扩散和聚集是路易体病（LBD）的病理标志，包括帕金森病（PD）和路易体痴呆（DLB）。虽然存在多种aSyn蛋白构象的证据，因其独特的生物学特性常被称为“毒株”，但尚不清楚PD和DLB是否由aSyn毒株差异导致，且缺乏区分PD和DLB的生物标志物。此外，虽然在脑外（皮肤、肠道、血液）已检测到aSyn的病理形式，但其外周aSyn种类的功能意义尚不清楚。在此，我们开发了检测方法，使用对两种不同产生的aSyn种类具有选择性的单克隆抗体——称为毒株A和毒株B，并通过免疫组织化学、酶联免疫吸附测定和免疫印迹，用它们来评估人脑组织、脑脊液（CSF）和血浆。令人惊讶的是，我们发现这些抗体检测到的血浆aSyn种类在一个发现队列（宾夕法尼亚大学，n = 235，曲线下面积0.83）和一个多中心复制队列（帕金森病生物标志物项目，或PDBP，n = 200，曲线下面积0.72）中区分了PD与DLB个体。毒株A抗体检测到的aSyn血浆种类还预测了PD患者的认知衰退率。我们在脑脊液中未发现aSyn毒株的证据，并且从血浆与脑部分离的种类以及在PD与DLB中，aSyn纤维化模板化能力有所不同。综上所述，我们的研究结果表明，aSyn构象差异可能影响病理性aSyn的临床表现和皮质扩散。此外，这些aSyn毒株在血浆中的富集暗示了非中枢神经系统来源。
