阿尔茨海默病患者中年龄校正后脑脊液β-分泌酶活性降低。

Decrease in age-adjusted cerebrospinal fluid beta-secretase activity in Alzheimer's subjects.

作者信息

Wu Guoxin, Sankaranarayanan Sethu, Tugusheva Kate, Kahana Jason, Seabrook Guy, Shi Xiao-Ping, King Elizabeth, Devanarayan Viswanath, Cook Jacquelynn J, Simon Adam J

机构信息

Alzheimer's Research, Merck Research Laboratory, West Point, PA, USA.

出版信息

Clin Biochem. 2008 Aug;41(12):986-96. doi: 10.1016/j.clinbiochem.2008.04.022. Epub 2008 May 6.

DOI:10.1016/j.clinbiochem.2008.04.022

PMID:18489907

Abstract

OBJECTIVES

To develop a novel cerebrospinal fluid (CSF) beta-secretase-1 activity assay and evaluate beta-secretase-1 (BACE-1) activity as a potential biomarker in human Alzheimer's disease.

METHODS

The assay consisted of an enzymatic reaction of CSF samples with an optimized beta-secretase peptide substrate and the cleavage products were detected using a neo-epitope specific antibody.

RESULTS

The CSF BACE-1 activity assay described exhibits time, temperature, dose, and pH dependence, with sensitivity down to <1 pM of recombinant BACE-1 enzyme, and is completely blocked by BACE-1 inhibitors. The endogenous BACE-1 enzyme in CSF appears to exist as a c-terminally truncated protein, based on both western blotting and capture-based activity assays. In a small cohort of human subjects, an age-dependent increase in CSF BACE activity was observed (~1.0 pM/year, p<0.05). In Alzheimer's disease subjects, a significant decline in age-adjusted CSF BACE activity was observed compared to controls (56% in the log-transformed scale, p=0.02).

CONCLUSION

We have developed a robust assay to measure CSF BACE-1 activity which could serve as a potential biomarker in human Alzheimer's disease subjects.

摘要

目的

开发一种新型脑脊液（CSF）β-分泌酶-1活性检测方法，并评估β-分泌酶-1（BACE-1）活性作为人类阿尔茨海默病潜在生物标志物的可能性。

方法

该检测方法包括脑脊液样本与优化的β-分泌酶肽底物的酶促反应，并使用新表位特异性抗体检测裂解产物。

结果

所描述的脑脊液BACE-1活性检测方法表现出时间、温度、剂量和pH依赖性，对重组BACE-1酶的敏感性低至<1 pM，并且被BACE-1抑制剂完全阻断。基于蛋白质印迹法和基于捕获的活性检测，脑脊液中的内源性BACE-1酶似乎以C末端截短的蛋白质形式存在。在一小群人类受试者中，观察到脑脊液BACE活性随年龄增加（约1.0 pM/年，p<0.05）。在阿尔茨海默病患者中，与对照组相比，观察到年龄校正后的脑脊液BACE活性显著下降（对数转换后为56%，p=0.02）。