Differential expression analysis of miRNAs expressed in blood and CSF of Huntington's disease [miRNA array]. Differential expression analysis of miRNAs expressed in blood and CSF of Huntington's disease [miRNA array]

Huntington’s disease (HD) is an autosomal-dominant neurodegenerative disorder caused by the CAG expansion in the Huntingtin (HTT) gene. Several studies have shown the potential of microRNAs as biomarkers in neurodegenerative diseases. However, no bona fide microRNAs have been identified as promising diagnostic biomarkers for HD. As part of the PREDICT-HD project, here we performed NanoString on blood samples of 115 pre-manifest HD cases and 111 controls in an effort to provide promising biomarkers for the diagnostic of HD or the disease processes tracking. The results showed that five miRNAs (miR-1252, miR-433, miR-553, miR-138-5p and miR-2053) are significantly differentially expressed in pre-manifest gene-positive HD cases vs. gene-negative controls. We also explored the miRNAs associated with HD severity by correlating the miRNA expression with CAP scores of 115 pre-manifest HD samples and found that 41 and 24 miRNAs are negatively and positively correlated with CAP scores significantly. Furthermore, target gene set of miR-138 and miR-433 , its co-expressed mRNAs in ROSMAP, and differentially expressed mRNAs of HD reveal four overlap genes (CASP7, CNOT6L, TMED and FERMT2). In summary, our study provides new insights into biomarker of Huntington’s disease by analyzing the cross-sectional miRNA expression data in blood. Overall design: In this study, total RNAs for 233 blood samples, incl. 113 controls and 120 HD, were requested from PREDICT-HD consortium. We then used NanoString to measure the miRNA expression levels of these samples. After normalization and filtering, we called differential expressed miRNAs between control and HD using SVA, after ajusting the covariates.

亨廷顿舞蹈症（Huntington’s disease, HD）是一种由亨廷顿（HTT）基因CAG三核苷酸重复扩增引发的常染色体显性遗传性神经退行性疾病。已有多项研究证实，微小RNA（microRNA, miRNA）可作为神经退行性疾病的潜在生物标志物，但目前尚未有公认的微小RNA被确立为亨廷顿舞蹈症极具前景的诊断生物标志物。作为PREDICT-HD项目的一部分，本研究对115例症状前亨廷顿舞蹈症患者与111例健康对照的血液样本开展NanoString检测，以期为亨廷顿舞蹈症的诊断或疾病进程追踪发掘可靠的生物标志物。

研究结果显示，相较于基因阴性的健康对照，5种微小RNA（miR-1252、miR-433、miR-553、miR-138-5p及miR-2053）在症状前基因阳性的亨廷顿舞蹈症患者中存在显著差异表达。此外，本研究通过关联115例症状前亨廷顿舞蹈症样本的微小RNA表达水平与CAP评分，探究了与亨廷顿舞蹈症严重程度相关的微小RNA，发现分别有41种与24种微小RNA与CAP评分呈显著负相关与正相关。进一步地，针对miR-138与miR-433的靶基因集、二者在ROSMAP数据库中共表达的信使RNA（messenger RNA, mRNA），以及亨廷顿舞蹈症差异表达的信使RNA进行整合分析，最终筛选得到4个重叠基因：CASP7、CNOT6L、TMED及FERMT2。

综上，本研究通过分析血液样本的横断面微小RNA表达数据，为亨廷顿舞蹈症的生物标志物研究提供了新的视角。

总体实验设计：本研究从PREDICT-HD联盟获取了233份血液样本的总RNA，其中包含113例健康对照与120例亨廷顿舞蹈症患者样本。随后采用NanoString技术检测所有样本的微小RNA表达水平。经过标准化处理与过滤后，我们通过SVA方法校正混杂变量，对对照组与亨廷顿舞蹈症组的差异表达微小RNA进行了鉴定。