发现疾病相关的α突触核蛋白通过增强ELISA在转基因小鼠表达人A53T的突变脑α突触核蛋白
Summary
An ELISA offering a novel quantitative approach is described. It specifically detects disease-associated α-synuclein (αSD) in a transgenic mouse model (M83) of synucleinopathy using several antibodies against either the Ser129 phosphorylated αS form or the C-terminal part of the protein.
Abstract
除了 像Western印迹确定的方法，需要新的方法来快速并容易地量化疾病相关α突触核蛋白（αSD）在突触核蛋白病的实验模型。转基因小鼠线（M83）过表达人类A53TαS和自发发展8和22个月的年龄，特点是症状包括体重下降，虚脱，和严重运动功能障碍之间的戏剧性的临床表型，被用于这项研究。为αSD（疾病相关αS）在这些小鼠中的分子分析，将ELISA被设计成特异性量化αS中的D患病小鼠。中枢神经系统在该小鼠模型的分析表明αSD的存在主要是在尾部脑区域和脊髓。有不同的实验条件之间αS 二维分布无显着差异，导致临床疾病， 即在uninoculated和正常老化的转基因小鼠在接种与患病小鼠大脑提取物的小鼠。的αSð使用免疫抗体对抗Ser129的特异性检测磷酸化ELISAαS与Western blot和免疫组化基本得到相关。出乎意料的是，类似的结果，观察对αS的C-末端部分的几个其它抗体。 αSD的传播，这表明了“朊病毒样”机制的参与，因此，可以容易地监测和定量用ELISA方法该小鼠模型。
Introduction
Most current methods for detecting disease-associated α-synuclein (αSD) in experimental models of Parkinson’s disease (PD), such as immunohistochemistry or Western blot, are time-consuming and not quantitative. This neurodegenerative disease is characterized by alpha-synuclein aggregation mainly in the form of inclusions containing an aggregated form of the normally soluble presynaptic protein αS1,2 (Lewy bodies and Lewy neurites). Normally only marginally phosphorylated, αS is hyperphosphorylated at its serine 129 residue in these inclusions3 and can be monitored by antibodies specifically directed against Ser129 phosphorylated αS, thus providing a reliable marker of the pathology.
Recent research suggests that a “prion-like” mechanism could be involved in the propagation of αS aggregation within the nervous system of an affected patient4,5. These studies reported the acceleration of a synucleinopathy by inoculating brain extracts containing αSD into a transgenic mouse model (M83) expressing an A53T mutated human αS protein associated with a severe motor impairment occurring as the mice age6. In the same manner, intra-cerebral inoculation of aggregated recombinant αS in the same M83 mouse model confirmed the acceleration of aggregation5. The induction of deposits of phosphorylated αS has also been reported after inoculation of C57Bl/6 wild-type mice with either fibrillar recombinant αS or brain extracts from human DLB patients7,8. Sacino et al.9 recently pointed out that after injection of fibrillar human αS, a widespread and progressive cerebral αS inclusion formation could be induced in M83 mice, but not in E46K transgenic mice or non-transgenic mice in which induced αS inclusions were transient, and mainly restricted to the site of injection. Recent studies on monkeys confirmed propagation of αS aggregates after inoculation of PD-derived extracts in species closer to humans10.
The link between αS alterations and Parkinson’s disease suggest that αSD is a potential biomarker for Parkinson’s disease11. A recent study showed the detection of oligomeric soluble aggregates of α-synuclein in human cerebro-spinal fluid (CSF) and plasma as a potential biomarker for Parkinson’s disease based on a conventional sandwich system ELISA using the same antibody to capture and detect αS12. Based on the same method, multimeric proteins were recognized in biological samples, including the brain, because there are multiple copies of epitopes present in the assembled forms13. Very recently, pathological αS in the CSF of patients with a proven Lewy body pathology was detected using both an ELISA kit with a highly specific antibody against αSD (5G4) and an immunoprecipitation assay14. These methods could differentiate patients with PD/DLB from other types of dementia.
The “prion-like” propagation of αS aggregation was further studied in transgenic mouse model M83 using an ELISA approach that was designed to specifically identify αSD15. In this study, we report the detailed ELISA protocol used to quantitatively detect αSD in sick mice (whether or not inoculated with αSD from sick M83 mice) and more especially in the brain regions specifically targeted by the pathological process in this M83 transgenic mouse model4.
Protocol
Representative Results
Discussion
采用ELISA检测法被证明特别是从小鼠脑组织匀浆检测αSÐ直接的病在M83转基因小鼠模型中。事实上，这ELISA可以很容易地分辨健康M83小鼠在高盐缓冲只使用全脑组织匀浆病鼠M83。
使用这种ELISA成功的结果的最重要的步骤是：正确地制定必要的手巧，以防止在切除损坏解剖老鼠大脑的不同区域;执行样本稀释只在HS缓冲区;和抗体的选择，因为并非所有的抗体将工作在ELISA格?…
Declarações
The authors have nothing to disclose.
Acknowledgements
作者要感谢达盖拉德的接种和后续的动物实验。这项工作是由ANSES（法语局食品，环境和职业健康安全），并从基金会法国帕金森的赠款支持。
Materials
| LB509 | Abcam | ab27766 | Detection antibody 1/2000 | |
| AS11 | Produced at Anses | Detection antibody 1/1000 | ||
| 4D6 | Abcam | ab1903 | Detection antibody 1/2000 | |
| PSer129 | Abcam | ab59264 | Detection antibody 1/3000 | |
| PSer129 EP1536Y | Abcam | ab51253 | Detection antibody 1/1000 | |
| syn514 | Abcam | ab24717 | Detection antibody 1/500 | |
| clone 42 | BD Biosciences | 610787 | Coating and detection antibody (1/2000) | |
| 8A5 | Provided by Dr. Anderson | Detection antibody 1/2000 | ||
| polyclonal anti-αsyn antibody | Millipore | AB5038P | Coating antibody | |
| Anti-mouse IgG HRP conjugate | Southern Biotech | 1010-05 | ||
| Anti-rabbit IgG HRP conjugate | Southern Biotech | 4010-05 | ||
| Goat anti-mouse IgG HRP conjugate | Dianova | 115-035-164 | ||
| HS buffer | Tris-HCl 50 mM | Euromedex | 26-128-3094-B | Adjust at pH 7.5 and keep at 4°C |
| NaCl 750 mM | Euromedex | 1112-A | ||
| EDTA 5 mM | Euromedex | EU0007-B | ||
| DTT 1 mM | Sigma | 43815 | ||
| PBS | Na2HPO4 1 mM | Euromedex | 1309 | Adjust at pH 7.5 |
| KH2PO4 1,5 mM | Euromedex | 2018 | ||
| NaCl 137 mM | Euromedex | 1112-A | ||
| KCl 2,7 mM | Euromedex | P017 | ||
| Tween 20 | Euromedex | 2001-C | ||
| BSA | Sigma | A7906 | ||
| DTT 1 mM | Sigma | 43815 | stock solution 100 mM, toxic | |
| 1% phosphatase cocktail | Pierce | 78428 | ||
| 1% protease inhibitor cocktail | Roche | 04 693 132 001 | 50 X concentrated | |
| Microplate MaxiSorpTM | Thermo Scientific | 442404 | ||
| Tampon carbonate 50 mM pH 9.6 | Na2CO3, 10H2O | Sigma | 71360 | 2.86 g/L |
| NaHCO3 | Merk | 6329 | 3.36 g/L, pH9.6 | |
| Superblock T20 PBS blocking buffer | Pierce | E6423H | 10 X concentrated | |
| TMB | Sigma | T0440 | Used for ELISA | |
| TMB | Analytik Jena AG | 847-0104200302 | Used for epitope mapping | |
| HCl 1N | Chimie plus | 40030 | ||
| Ribolyser | Thermo | Fast prep FP120 | keep on ice at this step | |
| Grinding tubes | Biorad | 355-1197 | ||
| Plate washer | Tecan | Columbus Pro | ||
| Plate reader | Biorad | Model 680 | ||
| Low power magnifier | VWR | 630-1062 | X8 magnification | |
| Forceps Dumont#7 | WPI | 14097 | For dissection steps | |
| Transfer pipette 1ml Samso | Samso | 043231 | ||
| 1,5 ml tubes | Dutscher | 033290 |
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