Wild Edward J, Boggio Roberto, Langbehn Douglas, Robertson Nicola, Haider Salman, Miller James R C, Zetterberg Henrik, Leavitt Blair R, Kuhn Rainer, Tabrizi Sarah J, Macdonald Douglas, Weiss Andreas
J Clin Invest. 2015 May;125(5):1979-86. doi: 10.1172/JCI80743. Epub 2015 Apr 6.
Quantification of disease-associated proteins in the cerebrospinal fluid (CSF) has been critical for the study and treatment of several neurodegenerative disorders; however, mutant huntingtin protein (mHTT), the cause of Huntington's disease (HD), is at very low levels in CSF and, to our knowledge, has never been measured previously.
We developed an ultrasensitive single-molecule counting (SMC) mHTT immunoassay that was used to quantify mHTT levels in CSF samples from individuals bearing the HD mutation and from control individuals in 2 independent cohorts.
This SMC mHTT immunoassay demonstrated high specificity for mHTT, high sensitivity with a femtomolar detection threshold, and a broad dynamic range. Analysis of the CSF samples showed that mHTT was undetectable in CSF from all controls but quantifiable in nearly all mutation carriers. The mHTT concentration in CSF was approximately 3-fold higher in patients with manifest HD than in premanifest mutation carriers. Moreover, mHTT levels increased as the disease progressed and were associated with 5-year onset probability. The mHTT concentration independently predicted cognitive and motor dysfunction. Furthermore, the level of mHTT was associated with the concentrations of tau and neurofilament light chain in the CSF, suggesting a neuronal origin for the detected mHTT.
We have demonstrated that mHTT can be quantified in CSF from HD patients using the described SMC mHTT immunoassay. Moreover, the level of mHTT detected is associated with proximity to disease onset and diminished cognitive and motor function. The ability to quantify CSF mHTT will facilitate the study of HD, and mHTT quantification could potentially serve as a biomarker for the development and testing of experimental mHTT-lowering therapies for HD.
Not applicable.
CHDI Foundation Inc.; Medical Research Council (MRC) UK; National Institutes for Health Research (NIHR); Rosetrees Trust; Swedish Research Council; and Knut and Alice Wallenberg Foundation.
脑脊液（CSF）中疾病相关蛋白的定量分析对于多种神经退行性疾病的研究和治疗至关重要；然而，亨廷顿舞蹈病（HD）的病因——突变型亨廷顿蛋白（mHTT）在脑脊液中的含量极低，据我们所知，此前从未被检测到过。
我们开发了一种超灵敏的单分子计数（SMC）mHTT免疫测定法，用于对来自两个独立队列中携带HD突变个体和对照个体的脑脊液样本中的mHTT水平进行定量。
这种SMC mHTT免疫测定法对mHTT具有高特异性、飞摩尔检测阈值的高灵敏度以及较宽的动态范围。对脑脊液样本的分析表明，所有对照的脑脊液中均未检测到mHTT，但几乎所有突变携带者的脑脊液中均可检测到。有明显HD症状的患者脑脊液中的mHTT浓度比症状前突变携带者高约3倍。此外，mHTT水平随着疾病进展而升高，并与5年发病概率相关。mHTT浓度可独立预测认知和运动功能障碍。此外，mHTT水平与脑脊液中tau蛋白和神经丝轻链的浓度相关，提示检测到的mHTT起源于神经元。
我们已经证明，使用所述的SMC mHTT免疫测定法可以对HD患者脑脊液中的mHTT进行定量。此外，检测到的mHTT水平与疾病发作的临近程度以及认知和运动功能减退有关。脑脊液mHTT定量能力将有助于HD的研究，mHTT定量可能作为HD实验性降mHTT疗法开发和测试的生物标志物。
不适用。
CHDI基金会；英国医学研究理事会（MRC）；美国国立卫生研究院（NIHR）；罗斯树信托基金；瑞典研究理事会；以及克努特和爱丽丝·瓦伦贝里基金会。
