Il rilevamento della malattia associata α-sinucleina da avanzato ELISA nel cervello di topi transgenici A53T umano Mutato α-sinucleina
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
Oltre ai metodi affermati come Western blot, sono necessari nuovi metodi per quantificare rapidamente e facilmente malattia associata α-sinucleina (αS D) in modelli sperimentali di synucleopathies. Una linea di topi transgenici (M83) che sovra-esprimono i αS A53T umani e sviluppare spontaneamente una drammatica fenotipo clinico tra gli otto ei 22 mesi di età, caratterizzata da sintomi quali la perdita di peso, prostrazione e disabilità motoria grave, è stato utilizzato in questo studio. Per le analisi molecolari di αS D (αS associata a malattia) in questi topi, un test ELISA è stato progettato per quantificare specificamente αS D nei topi malati. Analisi del sistema nervoso centrale in questo modello di topo ha mostrato la presenza di αS D principalmente nelle regioni del cervello caudale e il midollo spinale. Non ci sono state differenze nella distribuzione αS D tra diverse condizioni sperimentali che portano alla malattia clinica, vale a dire, in uninoculated e normalmente invecchiamento topi transgenici e in topi inoculati con estratti di cervello di topi malati. La rilevazione specifica di αS D immunoreactivity utilizzando un anticorpo contro Ser129 fosforilata αS di ELISA essenzialmente correlati con quello ottenuto da Western Blot e immunoistochimica. Inaspettatamente, risultati simili sono stati osservati con diversi altri anticorpi contro la parte C-terminale di αS. La propagazione di αS D, suggerendo il coinvolgimento di un meccanismo di "prioni-like", può quindi essere facilmente monitorato e quantificata in questo modello murino utilizzando un approccio ELISA.
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
L'uso di un ELISA è stato dimostrato per rilevare specificamente αS D direttamente da omogenati di cervello mouse durante la malattia nel modello di topo transgenico M83. In effetti, questo ELISA potrebbe facilmente distinguere malati topi M83 da topi sani M83 utilizzando solo intere omogenati di cervello in tampone alta Salt.
Le fasi più critiche per ottenere risultati di successo che utilizzano questo ELISA sono: dissezione correttamente le diverse regioni del cervello di…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Gli autori desiderano ringraziare Damien Gaillard per vaccinazioni e il follow-up di esperimenti sugli animali. Questo lavoro è stato sostenuto da ANSES (Agenzia francese per l'Alimentazione, Ambiente e Salute e Sicurezza), e da una sovvenzione della Fondazione Parkinson Francia.
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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