RESUMEN
After encounter with a central nervous system (CNS)-derived autoantigen, lymphocytes leave the lymph nodes and enter the CNS. This event leads only rarely to subsequent tissue damage. Genes relevant to CNS pathology after cell infiltration are largely undefined. Myelin-oligodendrocyte-glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis (MS), a chronic autoimmune disease of the CNS that results in disability. To assess genes that are involved in encephalitogenicity and subsequent tissue damage mediated by CNS-infiltrating cells, we performed a DNA microarray analysis from cells derived from lymph nodes and eluted from CNS in LEW.1AV1 (RT1av1) rats immunized with MOG 91-108. The data was compared to immunizations with adjuvant alone or naive rats and to immunizations with the immunogenic but not encephalitogenic MOG 73-90 peptide. Here, we show involvement of Cd38, Cxcr4 and Akt and confirm these findings by the use of Cd38-knockout (B6.129P2-Cd38tm1Lnd/J) mice, S1P-receptor modulation during EAE and quantitative expression analysis in individuals with MS. The hereby-defined underlying pathways indicate cellular activation and migration pathways mediated by G-protein-coupled receptors as crucial events in CNS tissue damage. These pathways can be further explored for novel therapeutic interventions.
Asunto(s)
Encefalomielitis Autoinmune Experimental/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Esclerosis Múltiple/genética , ADP-Ribosil Ciclasa 1/metabolismo , Animales , Movimiento Celular/efectos de los fármacos , Quimiocina CXCL12/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Femenino , Clorhidrato de Fingolimod/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inmunización , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/patología , Ratones Endogámicos C57BL , Esclerosis Múltiple/patología , Glicoproteína Mielina-Oligodendrócito , Péptidos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Médula Espinal/efectos de los fármacos , Médula Espinal/patologíaRESUMEN
Experimental autoimmune encephalomyelitis (EAE) can be actively induced with the extracellular domain of myelin oligodendrocyte glycoprotein (MOG 1-125). MOG-EAE closely mimics multiple sclerosis (MS) especially as far as demyelination, lesion formation and axonal pathology are concerned. MOG 91-108 is the encephalitogenic stretch within MOG 1-125 in two EAE-susceptible MHC congenic LEW rat strains [LEW.1AV1 (RT1(av1)) and LEW.1N (RT1(n))] and DA (RT1(av1)) rats. In LEW.1AV1 rats, disease could be induced with MOG 96-104 and to a lesser extent with MOG 98-106, whereas in LEW.1N rats, only MOG 98-106 was pathogenic. Both peptides bound well to their restricting MHC class II molecules, i.e., RT1.D(n) in the LEW.1N rat and RT1.B(a) in the LEW.1AV1 rat. TCR spectratyping of MOG 91-108 immunized LEW.1N, LEW.1AV1 and DA rats revealed that MHC class II determined the TCRBV preference of CNS infiltrating T cells. The data demonstrate that the most critical factor in inducing MS like pathology is presentation of autoantigenic peptides on MHC class II molecules resulting in demyelination and axonal pathology.
Asunto(s)
Presentación de Antígeno/inmunología , Autoantígenos/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Mapeo Epitopo , Antígenos de Histocompatibilidad Clase II/inmunología , Glicoproteína Asociada a Mielina/inmunología , Animales , Autoantígenos/química , Encefalomielitis Autoinmune Experimental/patología , Femenino , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/patología , Proteínas de la Mielina , Glicoproteína Asociada a Mielina/química , Glicoproteína Mielina-Oligodendrócito , Péptidos/inmunología , Ratas , Ratas Endogámicas Lew , Receptores de Antígenos de Linfocitos T alfa-beta/inmunologíaRESUMEN
To investigate the influence of antigen and restricting MHC class II molecule on the T cell repertoire, we varied the peptide source by immunizing either with myelin basic protein (MBP) (rat)63-88 or MBP(GUINEA PIG (GP))63-88, which differ in the core region of the peptide binding site at position 79 by a single exchange of threonine (T) to serine (S) and by altering the MHC by immunizing MHC congenic LEW (RT1(1)) and LEW.1W (RT1u) rats. In both MHC haplotypes both peptides lead to oligoclonal dominance of TCRBV8S2 expressing T cells within the central nervous system (CNS) as assessed by complementary determining region 3 (CDR3) spectratyping. In contrast cytofluorometric analysis indicated that only MBP(GP)63-88 in context with the RT1(l) haplotype of the LEW rat lead to strong expansions of TCRBV8S2 expressing T cells within the CNS. Importantly, the small conservative change from S to T at position 79 within MBP63-88 had a strong influence both on the encephalitogenic potential of the peptide and on the number of TCRBV8S2+ T cells infiltrating the CNS. These results demonstrate that even minor changes in only one side chain of an amino acid within an (auto)antigen can dramatically alter TCR avidity for certain MHC class II/peptide complexes.
Asunto(s)
Sistema Nervioso Central/metabolismo , Regiones Determinantes de Complementariedad , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Linfocitos T/metabolismo , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , División Celular , Separación Celular , Sistema Nervioso Central/patología , Encefalomielitis Autoinmune Experimental/inmunología , Citometría de Flujo , Cobayas , Haplotipos , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/metabolismo , Inmunización , Proteína Básica de Mielina/inmunología , Fragmentos de Péptidos/inmunología , Ratas , Ratas Endogámicas Lew , Serina , Linfocitos T/patología , TreoninaRESUMEN
Experimental autoimmune encephalomyelitis (EAE) in rats is a highly valuable model of multiple sclerosis (MS) because it mimics major hallmarks of the human disease. EAE induced with myelin-oligodendrocyte-glycoprotein (MOG) in DA rats is relapsing/remitting, and lesions in the central nervous system show inflammation, demyelination, and axonal and neuronal loss. Recently, bone marrow transplantation (BMT) was introduced as a novel strategy to treat MS, but its efficiency and the underlying mechanism are debatable. In MOG-induced EAE we found that BMT at the peak of EAE but not in the chronic phase leads to disease attenuation. In both settings, rats receiving bone marrow (BM) transplants were protected from subsequently induced relapses. These findings could be confirmed by histopathology in which rats receiving BM transplants did not have lesions compared with controls not receiving transplants. Importantly, the protective effect was achieved by allogeneic, syngeneic, and BM grafts from diseased rats. BMT resulted in increased numbers of CD4(+)CD25(bright) regulatory T cells, increased Foxp3 expression, a shift in T-cell epitope recognition, and a strong reduction of autoantibodies even after rechallenge with MOG. Thus, our results indicate potential mechanisms of how BMT may contribute to the improvement of MS and provide a rationale for its application in patients suffering from various autoimmune diseases.
Asunto(s)
Trasplante de Médula Ósea , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/terapia , Tolerancia Inmunológica , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/terapia , Animales , Autoanticuerpos/farmacología , Trasplante de Médula Ósea/efectos adversos , Modelos Animales de Enfermedad , Linfocitos/inmunología , Esclerosis Múltiple/patología , Proteínas de la Mielina , Glicoproteína Asociada a Mielina/inmunología , Glicoproteína Mielina-Oligodendrócito , Fenotipo , Ratas , Ratas Endogámicas ACI , Ratas Endogámicas , Recurrencia , Factores de TiempoRESUMEN
Axonal damage is a major morphological correlate and cause of permanent neurological deficits in patients with multiple sclerosis (MS), a multifocal, inflammatory and demyelinating disease of the central nervous system. Hyperphosphorylation and pathological aggregation of microtubule-associated protein tau is a common feature of many neurodegenerative diseases with axonal degeneration including Alzheimer's disease. We have therefore analyzed tau phosphorylation, solubility and distribution in the brainstem of rats with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Tau was hyperphosphorylated at several sites also phosphorylated in Alzheimer's disease and became partially detergent-insoluble in EAE brains. Morphological examination demonstrated accumulation of amorphous deposits of abnormally phosphorylated tau in the cell body and axons of neurons within demyelinating plaques. Hyperphosphorylation of tau was accompanied by up-regulation of p25, an activator of cyclin-dependent kinase 5. Phosphorylation of tau, activation of cdk5, and axonal pathology were significantly reduced when diseased rats were treated with prednisolone, a standard therapy of acute relapses in MS. Hyperphosphorylation of tau was not observed in a genetic or nutritional model of axonal degeneration or demyelination, suggesting that inflammation as detected in the brains of rats with EAE is the specific trigger of tau pathology. In summary, our data provide evidence that axonal damage in EAE and possibly MS is linked to tau pathology.
Asunto(s)
Encefalomielitis Autoinmune Experimental/metabolismo , Proteínas tau/fisiología , Animales , Western Blotting , Encéfalo/metabolismo , Células Cultivadas , Cuprizona/farmacología , Quinasa 5 Dependiente de la Ciclina , Quinasas Ciclina-Dependientes/metabolismo , Glucocorticoides/farmacología , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Microtúbulos/metabolismo , Modelos Genéticos , Enfermedades Neurodegenerativas/metabolismo , Oligodendroglía/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación , Prednisolona/farmacología , Estructura Terciaria de Proteína , Ratas , Factores de Tiempo , Regulación hacia Arriba , Proteínas tau/química , Proteínas tau/metabolismoRESUMEN
Most autoimmune diseases are associated with certain MHC class II haplotypes. Autoantigen-based specific immune therapy can lead either to beneficial or, in the context of inflammatory conditions, detrimental outcomes. Therefore, we designed a platform of peptides by combinatorial chemistry selected in a nonbiased Ag-independent approach for strong binding to the rat MHC class II isotype RT1.D(n) allelic product of the RT1(n) haplotype that is presenting autoantigen in myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis in LEW.1N rats. Peptide p17 (Ac-FWFLDNAPL-NH(2)) was capable of suppressing the induction of and also ameliorated established experimental autoimmune encephalomyelitis. MHC class II isotype and allele specificity of the therapeutic principle were demonstrated in myelin basic protein-induced experimental autoimmune encephalomyelitis in LEW rats bearing the RT1(l) haplotype. A general immunosuppressive effect of the treatment was excluded by allogeneic heart transplantation studies. In vitro studies demonstrated the blocking effect of p17 on autoantigenic T cell responses. We thus demonstrate a rational design of strong MHC class II-binding peptides with absolute isotype and allele specificity able to compete for autoantigenic sequences presented on disease-associated MHC class II molecules.
Asunto(s)
Alelos , Encefalomielitis Autoinmune Experimental/genética , Encefalomielitis Autoinmune Experimental/inmunología , Antígenos de Histocompatibilidad Clase II/inmunología , Péptidos/inmunología , Secuencia de Aminoácidos , Animales , Autoantígenos/inmunología , Citocinas/inmunología , Proteínas de la Mielina , Glicoproteína Asociada a Mielina/inmunología , Glicoproteína Mielina-Oligodendrócito , Biblioteca de Péptidos , Isoformas de Proteínas/inmunología , Ratas , Ratas Endogámicas Lew , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the CNS with associated axonal loss. There is strong evidence for an autoimmune pathogenesis driven by myelin-specific T cells. Myelin oligodendrocyte glycoprotein (MOG) induces a type of experimental autoimmune encephalomyelitis in animals which is very MS-like since there are demyelinating CNS lesions and axonal loss. This underscores the potential role of MOG in MS pathogenesis. We performed a T cell reactivity pattern analysis of MS patients at the onset of relapse or progression of neurological deficits and controls that were stratified for the genetic risk factor HLA-DRB1*1501. For the first time, we show that there is an HLA-DR-restricted promiscuous dominant epitope for CD4(+) T cells within the transmembrane/intracellular part of MOG comprising aa 146-154 (FLCLQYRLR). Surprisingly, controls had broader T cell reactivity patterns toward MOG peptides compared with MS patients, and the transmembrane and intracellular parts of MOG were much more immunogenic compared with the extracellular part. Measurements of in vitro binding affinities revealed that HLA-DRB1*1501 molecules bound MOG 146-154 with intermediate and HLA-DRB1*0401 molecules with weak affinities. The binding of MOG 146-154 was comparable or better than myelin basic protein 85-99, which is the dominant myelin basic protein epitope in context with HLA-DRB1*1501 molecules in MS patients. This is the first study in which the data underscore the need to investigate the pathogenic or regulatory role of the transmembrane and intracellular part of MOG for MS in more detail.