Pre-symptomatic qPCR blood test based on Parkinson’s disease-specific angiogenin-derived transfer RNA fragments

Rapid, simple and reliable blood tests for Parkinson’s disease (PD) may enable pre-symptomatic diagnosis and facilitate disease-changing treatments. Here, we report escalated elevated levels of angiogenin-cleaved a disease specific group of nuclear genome-originated tRNA fragments (hereafter, PD-tRFs) carrying a unique seven-nucleotide motif in substantia nigra, cerebrospinal fluid and blood of PD patients. A blood test using RNA isolated from whole blood and dual multiplexl qPCR primers for PD-tRFs and mitochondrial-originated tRFs (MT-tRFs) successfully distinguished pre-symptomatic PD patients from controls, outperforming traditional clinical scoring (ROC-AUC of 0.86 vs. 0.73). Indicating relevance to disease symptoms, PD patients carrying GBA, SNCA or LRRK2 mutations presented elevated blood PD/MT-tRF ratios compared to mutations-carrying non-symptomatic individuals which indicates relevance to disease symptoms. Furthermore, PD-tRFs’ potential for ribosomal association predicted translational inhibition. Intriguingly, PD-tRFs levels declined both in patients’ blood following deep brain stimulation andas well as in in depolarized neuroblastoma cells where PD-tRFs presented transientlydepolirization impaired impacted ribosomal associations. Our findings facilitate a sensitive and accurate blood test for early PD. 37 blood samples of Parkinson's disease (PD) and controls, as well as 8 substantia nigra samples of PD patients were used to exteact short RNA. PD patients had various disease durations and Lewy bodies scores.

针对帕金森病（Parkinson’s disease, PD）的快速、简便且可靠的血液检测，有望实现症状前诊断并助力改变疾病进程的治疗。本研究报道，帕金森病患者黑质、脑脊液及血液中，存在一组由血管生成素切割的疾病特异性核基因组起源转运RNA片段（transfer RNA fragments, tRFs，后文简称PD-tRFs），其携带独特的七核苷酸基序。我们采用从全血中分离的RNA，结合针对PD-tRFs与线粒体起源tRFs（mitochondrial-originated tRFs, MT-tRFs）的双重多重定量聚合酶链反应（quantitative PCR, qPCR）引物建立的血液检测方法，成功将症状前帕金森病患者与健康对照区分开来，其性能优于传统临床评分（受试者工作特征曲线下面积（Receiver Operating Characteristic Area Under the Curve, ROC-AUC）分别为0.86与0.73）。与疾病症状相关的是，携带GBA、SNCA或LRRK2基因突变的帕金森病患者，其血液中PD-tRFs与MT-tRFs的比值较携带突变但无症状的个体更高，这表明该指标与疾病症状存在关联。此外，PD-tRFs具有与核糖体结合的潜力，提示其可能抑制翻译过程。有趣的是，接受深部脑刺激（deep brain stimulation）的患者血液中PD-tRFs水平会下降，在去极化的神经母细胞瘤细胞中亦是如此；在此类细胞中，一过性去极化损伤会影响PD-tRFs与核糖体的结合。本研究结果为早期帕金森病提供了一种灵敏且准确的血液检测方法。本研究共纳入37份帕金森病患者与健康对照的血液样本，以及8份帕金森病患者的黑质样本，用于提取短链RNA。帕金森病患者的病程及路易体评分存在差异。