Een<em> Ex vivo</em> Model van een Oligodendrocyte gericht T-Cell Attack in Acute Brain Slices
Summary
To address mechanisms of demyelination and neuronal apoptosis in cortical lesions of inflammatory demyelinating disorders, different animal models are used. We here describe an ex vivo approach by using oligodendrocyte-specific CD8+ T-cells on brain slices, resulting in oligodendroglial and neuronal death. Potential applications and limitations of the model are discussed.
Abstract
Death of oligodendrocytes accompanied by destruction of neurons and axons are typical histopathological findings in cortical and subcortical grey matter lesions in inflammatory demyelinating disorders like multiple sclerosis (MS). In these disorders, mainly CD8+ T-cells of putative specificity for myelin- and oligodendrocyte-related antigens are found, so that neuronal apoptosis in grey matter lesions may be a collateral effect of these cells. Different types of animal models are established to study the underlying mechanisms of the mentioned pathophysiological processes. However, although they mimic some aspects of MS, it is impossible to dissect the exact mechanism and time course of ‘‘collateral’’ neuronal cell death. To address this course, here we show a protocol to study the mechanisms and time response of neuronal damage following an oligodendrocyte-directed CD8+ T cell attack. To target only the myelin sheath and the oligodendrocytes, in vitro activated oligodendrocyte-specific CD8+ T-cells are transferred into acutely isolated brain slices. After a defined incubation period, myelin and neuronal damage can be analysed in different regions of interest. Potential applications and limitations of this model will be discussed.
Introduction
Death of oligodendrocytes and destruction of the myelin sheath accompanied by loss of neurons and axons are typical pathological findings in grey matter lesions in individuals suffering from multiple sclerosis (MS)1,2. Cortical lesions can be divided so far in three different subtypes2: subpial, intracortical and leukocortical lesions. In comparison to white matter plaques, infiltrates are characterized by a predominance of CD8+ T-cells, suggesting their possible decisive role in grey matter inflammation3. Furthermore, oligoclonal expansions in blood, cerebrospinal fluid (CSF) and within inflammatory lesions can be found for CD8+ T-cells themselves4-6.
In line with this, it is assumed that CD8+ T-cells may be specific for different myelin proteins7,8. Indeed, CD8+ T-cells are found near oligodendrocytes and myelin sheaths9,10 that show MHC I expression11 and might therefore be responsible for the loss of the myelin sheath. This process is often seen together with extensive ‘‘collateral’’ neuronal and axonal damage within the central nervous system (CNS) grey matter1,2. In fact, direct and indirect death of oligodendrocytes and neurons is induced by CD8+ T-cells via two different mechanism: (i) cell membrane swelling and rupture due to the formation of cytotoxic granules following the release of perforins and granzymes and (ii) ligation to the Fas receptors or exposition of FasL on their surface8,12,13.
Different types of animal models are established to study the underlying mechanism of the mentioned processes. In this respect, primed CD8+ T-cells specific for autoantigens with induced expression in CNS glial cells, like oligodendrocytes or astrocytes, can be adoptively transferred to analyse ‘‘collateral’’ neuronal and axonal death in grey matter subsequently14,15. To perform such in vivo experiments is a big help to mimic some pathophysiological aspects of MS, however, this approach is not suited to resolve the underlying mechanism and kinetics of axonal damage and neuronal apoptosis.
To overcome these restrictions, an ex vivo approach was established to study the mechanisms and time course of neuronal cell death following a oligondendrocytes-directed CD8+ T-cell attack. Since only oligodendrocytes and therefore myelin sheath production should be targeted by immune cells, MHC class-I-restricted, ovalbumin (OVA)-reactive OT-I Tcells are used16. These cells are subsequently transferred into brain slices obtained from mice selectively expressing OVA in oligodendrocytes (ODC-OVA mice)17.
Protocol
Representative Results
Discussion
Verschillende dierlijke modellen zijn beschreven in de afgelopen decennia de pathologische kenmerken van inflammatoire demyeliniserende ziekten als MS pakken. In vivo muis en ratmodellen worden wijd gebruikt om pathofysiologie van de ziekte na te bootsen, namelijk analyse van de gevolgen van demyelinisatie en remyelinisatie processen en vermengde afleveringen van ontstekingen en neurodegeneratie. Toch alleen een ex vivo benadering maakt het mogelijk om de exacte onderliggende mechanismen te ontleden. <…
Divulgaciones
The authors have nothing to disclose.
Acknowledgements
This work was supported by the Interdisciplinary Center for Clinical Research (IZKF) Münster (SEED 03/12, SB), Deutsche Forschungsgemeinschaft (SFB TR128, TP B6 to S.G.M. ME3283/2-1 to S.G.M.) and by Innovative Medizinische Forschung, Münster (I-BI111316, SB and SGM).
Materials
| Name of Material/ Equipment | Company | Catalog Number | Comments/Description |
| 12-Well-plate | Corning | 3513 | |
| 2-Mercaptoethanol | Gibco | 31350-010 | |
| 2-Methylbutan | Roth | 3927.1 | |
| 70 µm strainer | Falcon | 352350 | |
| CaCl2 | Merck | 1.02382.0500 | calcium chloride |
| CD8+-isolation kit | Miltenyi Biotech | 130-090-859 | |
| D(+)-glukose | Merck | 1.08337.1000 | |
| DMEM | Gibco | 31966-021 | warm in 37 °C water bath before use |
| EDTA | Sigma | E5134 | |
| FCS | PAA Laboratories | A15-151 | fetal calve serum |
| gentamicin | Gibco | 15750-060 | |
| HEPES 1M | Gibco | 15630-050 | |
| IL-2 | Peprotech | 212-12 | |
| Isofluran | Abbott | 05260-05 | |
| KCl | Merck | 1.04933.0500 | potassium chloride |
| KHCO3 | Sigma | P9144 | potassium hydrogen carbonate |
| L-Glutamine | Gibco | 35050-038 | |
| MgSO4 | Merck | 1.05886.0500 | magnesium sulfate |
| NaCl | Sigma | 31434 | sodium chloride |
| NaH2PO4 * H2O | Merck | 1.06346.0500 | sodium hydrogen phosphate |
| NaHCO3 | Merck | 1.06329.0500 | sodium hydrogen carbonate |
| NaOH | Merck | 1.09137.1000 | sodium hydroxide |
| NH4Cl | Sigma | 213330 | ammonium chloride |
| Non Essential Amino Acid | Gibco | 11140-050 | |
| OVA (257-264) | Genscript | RP10611 | ovalbumin |
| PIPES | Sigma | P6757 | |
| Sukrose | Merck | 1.07687.1000 | |
| Tissue-Tek OCT | Sakura | 4583 |
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