Antibody-mediated inhibition of TNFR1 attenuates disease in a mouse model of multiple sclerosis.

Tumour necrosis factor (TNF) is a proinflammatory cytokine that is known to regulate inflammation in a number of autoimmune diseases, including multiple sclerosis (MS). Although targeting of TNF in models of MS has been successful, the pathological role of TNF in MS remains unclear due to clinical trials where the non-selective inhibition of TNF resulted in exacerbated disease. Subsequent experiments have indicated that this may have resulted from the divergent effects of the two TNF receptors, TNFR1 and TNFR2. Here we show that the selective targeting of TNFR1 with an antagonistic antibody ameliorates symptoms of the most common animal model of MS, experimental autoimmune encephalomyelitis (EAE), when given following both a prophylactic and therapeutic treatment regime. Our results demonstrate that antagonistic TNFR1-specific antibodies may represent a therapeutic approach for the treatment of MS in the future.

Neuromyelitis optica in Austria in 2011: to bridge the gap between neuroepidemiological research and practice in a study population of 8.4 million people.

BACKGROUND: In 2008 the Austrian Task Force for Neuromyelitis Optica (NMO) started a nation-wide network for information exchange and multi-centre collaboration. Their aim was to detect all patients with NMO or NMO spectrum disorders (NMO-SD) in Austria and to analyse their disease courses and response to treatment. METHODS: (1) As of March 2008, 1957 serum samples (of 1557 patients) have been tested with an established cell based immunofluorescence aquaporin-4 antibody (AQP4-ab) assay with a high sensitivity and specificity (both >95%). All tests were performed in a single reference laboratory (Clinical Dept. of Neurology of the Innsbruck Medical University). (2) A nation-wide survey with several calls for participation (via email newsletters, articles in the official journal of the Austrian Society of Neurology, and workshops) was initiated in 2008. All collected data will be presented in a way that allows that every individual patient can be traced back in order to ensure transparency and to avoid any data distortion in future meta-analyses. The careful and detailed presentation allows the visualization and comparison of the different disease courses in real time span. Failure and response to treatment are made visible at one glance. Database closure was 31 December 2011. All co-operators were offered co-authorship. RESULTS: All 71 NMO- or NMO-SD patients with AQP4-ab positivity (age range 12.3 to 79.6 years) were analysed in detail. Sex ratio (m:f = 1:7) and the proportion of patients without oligoclonal bands in cerebrospinal fluid (86.6%) were in line with previously published results. All identified patients were Caucasians. CONCLUSIONS: A nationwide collaboration amongst Austrian neurologists with good network communications made it possible to establish a database of 71 AQP4-ab positive patients with NMO/NMO-SD. This database is presented in detail and provides the basis for further studies and international cooperation in order to investigate this rare disease.

Plasma midregional pro-adrenomedullin improves prediction of functional outcome in ischemic stroke.

BACKGROUND: To evaluate if plasma levels of midregional pro-adrenomedullin (MR-proADM) improve prediction of functional outcome in ischemic stroke. METHODS: In 168 consecutive ischemic stroke patients, plasma levels of MR-proADM were measured within 24 hours from symptom onset. Functional outcome was assessed by the modified Rankin Scale (mRS) at 90 days following stroke. Logistic regression, receiver operating characteristics (ROC) curve analysis, net reclassification improvement (NRI), and Kaplan-Meier survival analysis were applied. RESULTS: Plasma MR-proADM levels were found significantly higher in patients with unfavourable (mRS 3-6) compared to favourable (mRS 0-2) outcomes. MR-proADM levels were entered into a predictive model including the patients' age, National Institutes of Health Stroke Scale (NIHSS), and the use of recanalization therapy. The area under the ROC curve did not increase significantly. However, category-free NRI of 0.577 (p<0.001) indicated a significant improvement in reclassification of patients. Furthermore, MR-proADM levels significantly improved reclassification of patients in the prediction of outcome by the Stroke Prognostication using Age and NIHSS-100 (SPAN-100; NRI = 0.175; p = 0.04). Kaplan-Meier survival analysis showed a rising risk of death with increasing MR-proADM quintiles. CONCLUSIONS: Plasma MR-proADM levels improve prediction of functional outcome in ischemic stroke when added to the patients' age, NIHSS on admission, and the use of recanalization therapy. Levels of MR-proADM in peripheral blood improve reclassification of patients when the SPAN-100 is used to predict the patients' functional outcome.

Preclinical retinal neurodegeneration in a model of multiple sclerosis.

Neurodegeneration plays a major role in multiple sclerosis (MS), in which it is thought to be the main determinant of permanent disability. However, the relationship between the immune response and the onset of neurodegeneration is still a matter of debate. Moreover, recent findings in MS patients raised the question of whether primary neurodegenerative changes can occur in the retina independent of optic nerve inflammation. Using a rat model of MS that frequently leads to optic neuritis, we have investigated the interconnection between neurodegenerative and inflammatory changes in the retina and the optic nerves with special focus on preclinical disease stages. We report that, before manifestation of optic neuritis, characterized by inflammatory infiltration and demyelination of the optic nerve, degeneration of retinal ganglion cell bodies had already begun and ultrastructural signs of axon degeneration could be detected. In addition, we observed an early activation of resident microglia in the retina. In the optic nerve, the highest density of activated microglia was found within the optic nerve head. In parallel, localized breakdown in the integrity of the blood-retinal barrier and aberrations in the organization of the blood-brain barrier marker aquaporin-4 in the optic nerves were observed during the preclinical phase, before onset of optic neuritis. From these findings, we conclude that early and subtle inflammatory changes in the retina and/or the optic nerve head reminiscent of those suggested for preclinical MS lesions may initiate the process of neurodegeneration in the retina before major histopathological signs of MS become manifest.

Complement activating antibodies to myelin oligodendrocyte glycoprotein in neuromyelitis optica and related disorders.

BACKGROUND: Serum autoantibodies against the water channel aquaporin-4 (AQP4) are important diagnostic biomarkers and pathogenic factors for neuromyelitis optica (NMO). However, AQP4-IgG are absent in 5-40% of all NMO patients and the target of the autoimmune response in these patients is unknown. Since recent studies indicate that autoimmune responses to myelin oligodendrocyte glycoprotein (MOG) can induce an NMO-like disease in experimental animal models, we speculate that MOG might be an autoantigen in AQP4-IgG seronegative NMO. Although high-titer autoantibodies to human native MOG were mainly detected in a subgroup of pediatric acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) patients, their role in NMO and High-risk NMO (HR-NMO; recurrent optic neuritis-rON or longitudinally extensive transverse myelitis-LETM) remains unresolved. RESULTS: We analyzed patients with definite NMO (n = 45), HR-NMO (n = 53), ADEM (n = 33), clinically isolated syndromes presenting with myelitis or optic neuritis (CIS, n = 32), MS (n = 71) and controls (n = 101; 24 other neurological diseases-OND, 27 systemic lupus erythematosus-SLE and 50 healthy subjects) for serum IgG to MOG and AQP4. Furthermore, we investigated whether these antibodies can mediate complement dependent cytotoxicity (CDC). AQP4-IgG was found in patients with NMO (n = 43, 96%), HR-NMO (n = 32, 60%) and in one CIS patient (3%), but was absent in ADEM, MS and controls. High-titer MOG-IgG was found in patients with ADEM (n = 14, 42%), NMO (n = 3, 7%), HR-NMO (n = 7, 13%, 5 rON and 2 LETM), CIS (n = 2, 6%), MS (n = 2, 3%) and controls (n = 3, 3%, two SLE and one OND). Two of the three MOG-IgG positive NMO patients and all seven MOG-IgG positive HR-NMO patients were negative for AQP4-IgG. Thus, MOG-IgG were found in both AQP4-IgG seronegative NMO patients and seven of 21 (33%) AQP4-IgG negative HR-NMO patients. Antibodies to MOG and AQP4 were predominantly of the IgG1 subtype, and were able to mediate CDC at high-titer levels. CONCLUSIONS: We could show for the first time that a subset of AQP4-IgG seronegative patients with NMO and HR-NMO exhibit a MOG-IgG mediated immune response, whereas MOG is not a target antigen in cases with an AQP4-directed humoral immune response.

Circulating Dickkopf-1 in acute ischemic stroke and clinically stable cerebrovascular disease.

OBJECTIVES: Previous data suggest that Dickkopf-1 (Dkk-1), an inhibitor of the canonical/ß-catenin cascade of the Wnt pathway, is upregulated in carotid atherosclerosis and acute myocardial ischemia. It is currently unclear if such upregulation also occurs in cerebral ischemia. METHODS: We measured plasma levels of Dkk-1 in patients with acute ischemic stroke (n=57) within 24h from symptom onset, in patients with clinically stable cerebrovascular disease (n=29) and in healthy controls (n=29). Stroke severity on admission was determined by the National Institutes of Stroke Scale (NIHSS). The modified Rankin Scale (mRS) served to define outcome at day 90. Ischemic stroke subtype and cause was determined by the Oxfordshire Community Stroke Project (OCSP) criteria and the Causative Classification of Stroke System (CCS). RESULTS: Dkk-1 plasma levels were significantly higher in acute stroke patients (median 727.1 pg/ml) as compared to patients with stable cerebrovascular disease (median 534.2 pg/ml; p=0.017) or healthy controls (median 371.3 pg/ml; p<0.001). The difference of Dkk-1 levels between patients with stable cerebrovascular disease and healthy controls was also significant (p=0.005). No significant differences in Dkk-1 plasma levels were found between different causes or subtypes of ischemic stroke. No correlation of Dkk-1 levels was found with stroke severity on admission and outcome at day 90. CONCLUSION: Our study provides for the first time evidence for a release of Dkk-1 into the circulation in patients with acute ischemic stroke and also in patients with clinically stable cerebrovascular disease.

Patterns of antibody binding to aquaporin-4 isoforms in neuromyelitis optica.

BACKGROUND: Neuromyelitis optica (NMO), a severe demyelinating disease, represents itself with optic neuritis and longitudinally extensive transverse myelitis. Serum NMO-IgG autoantibodies (Abs), a specific finding in NMO patients, target the water channel protein aquaporin-4 (AQP4), which is expressed as a long (M-1) or a short (M-23) isoform. METHODOLOGY/PRINCIPAL FINDINGS: The aim of this study was to analyze serum samples from patients with NMO and controls for the presence and epitope specificity of IgG and IgM anti-AQP4 Abs using an immunofluorescence assay with HEK293 cells expressing M-1 or M-23 human AQP4. We included 56 patients with definite NMO (n = 30) and high risk NMO (n = 26), 101 patients with multiple sclerosis, 27 patients with clinically isolated syndromes (CIS), 30 patients with systemic lupus erythematosus (SLE) or Sjögren's syndrome, 29 patients with other neurological diseases and 47 healthy controls. Serum anti-AQP4 M-23 IgG Abs were specifically detected in 29 NMO patients, 17 patients with high risk NMO and two patients with myelitis due to demyelination (CIS) and SLE. In contrast, IgM anti-AQP4 Abs were not only found in some NMO and high risk patients, but also in controls. The sensitivity of the M-23 AQP4 IgG assay was 97% for NMO and 65% for high risk NMO, with a specificity of 100% compared to the controls. Sensitivity with M-1 AQP4 transfected cells was lower for NMO (70%) and high risk NMO (39%). The conformational epitopes of M-23 AQP4 are the primary targets of NMO-IgG Abs, whereas M-1 AQP4 Abs are developed with increasing disease duration and number of relapses. CONCLUSIONS: Our results confirm M-23 AQP4-IgG Abs as reliable biomarkers in patients with NMO and high risk syndromes. M-1 and M-23 AQP4-IgG Abs are significantly associated with a higher number of relapses and longer disease duration.

Role of n-type voltage-dependent calcium channels in autoimmune optic neuritis.

OBJECTIVE: The aim of this study was to investigate the role of voltage-dependent calcium channels (VDCCs) in axon degeneration during autoimmune optic neuritis. METHODS: Calcium ion (Ca(2+)) influx into the optic nerve (ON) through VDCCs was investigated in a rat model of optic neuritis using manganese-enhanced magnetic resonance imaging and in vivo calcium imaging. After having identified the most relevant channel subtype (N-type VDCCs), we correlated immunohistochemistry of channel expression with ON histopathology. In the confirmatory part of this work, we performed a treatment study using omega-conotoxin GVIA, an N-type specific blocker. RESULTS: We observed that pathological Ca(2+) influx into ONs during optic neuritis is mediated via N-type VDCCs. By analyzing the expression of VDCCs in the inflamed ONs, we detected an upregulation of alpha(1B), the pore-forming subunit of N-type VDCCs, in demyelinated axons. However, high expression levels were also found on macrophages/activated microglia, and lower levels were detected on astrocytes. The relevance of N-type VDCCs for inflammation-induced axonal degeneration and the severity of optic neuritis was corroborated by treatment with omega-conotoxin GVIA. This blocker led to decreased axon and myelin degeneration in the ONs together with a reduced number of macrophages/activated microglia. These protective effects were confirmed by analyzing the spinal cords of the same animals. INTERPRETATION: We conclude that N-type VDCCs play an important role in inflammation-induced axon degeneration via two mechanisms: First, they directly mediate toxic Ca(2+) influx into the axons; and second, they contribute to macrophage/microglia function, thereby promoting secondary axonal damage. Ann Neurol 2009;66:81-93.

FTY720 rescue therapy in the dark agouti rat model of experimental autoimmune encephalomyelitis: expression of central nervous system genes and reversal of blood-brain-barrier damage.

FTY720 (fingolimod) is an oral sphingosine-1 phosphate (S1P) receptor modulator in phase III development for the treatment of multiple sclerosis. To further investigate its mode of action, we analyzed gene expression in the central nervous system (CNS) during experimental autoimmune encephalomyelitis (EAE). FTY720 downregulated inflammatory genes in addition to vascular adhesion molecules. It decreased the matrix metalloproteinase gene MMP-9 and increased its counterregulator--tissue inhibitor of metalloproteinase, TIMP-1--resulting in a proteolytic balance that favors preservation of blood-brain-barrier (BBB) integrity. Furthermore, FTY720 reduced S1P lyase that increases the S1P concentration in the brain, in line with a marked reversal of neurological deficits and raising the possibility for enhanced triggering of S1P receptors on resident brain cells. This is accompanied by an increase in S1P(1) and S1P(5) in contrast with the attenuation of S1P(3) and S1P(4). Late-stage rescue therapy with FTY720, even up to 1 month after EAE onset, reversed BBB leakiness and reduced demyelination, along with normalization of neurologic function. Our results indicate rapid blockade of ongoing disease processes by FTY720, and structural restoration of the CNS parenchyma, which is likely caused by the inhibition of autoimmune T cell infiltration and direct modulation of microvascular and/or glial cells.

Characterization of the encephalitogenic immune response in a model of multiple sclerosis.

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.

FTY720 sustains and restores neuronal function in the DA rat model of MOG-induced experimental autoimmune encephalomyelitis.

FTY720 (fingolimod) is an oral sphingosine 1-phosphate (S1P) receptor modulator under development for the treatment of multiple sclerosis (MS). To elucidate its effects in the central nervous system (CNS), we compared functional parameters of nerve conductance in the DA rat model of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) after preventive and therapeutic treatment. We demonstrate that prophylactic therapy protected against the emergence of EAE symptoms, neuropathology, and disturbances to visual and somatosensory evoked potentials (VEP, SEP). Moreover, therapeutic treatment from day 25 to 45 markedly reversed paralysis in established EAE and normalized the electrophysiological responses, correlating with decreased demyelination in the brain and spinal cord. The effectiveness of FTY720 in this model is likely due to several contributing factors. Evidence thus far supports its role in the reduction of inflammation and preservation of blood-brain-barrier integrity. FTY720 may also act via S1P receptors in glial cells to promote endogenous repair mechanisms that complement its immunomodulatory action.

Neurofascin as a novel target for autoantibody-mediated axonal injury.

Axonal injury is considered the major cause of disability in patients with multiple sclerosis (MS), but the underlying effector mechanisms are poorly understood. Starting with a proteomics-based approach, we identified neurofascin-specific autoantibodies in patients with MS. These autoantibodies recognize the native form of the extracellular domains of both neurofascin 186 (NF186), a neuronal protein concentrated in myelinated fibers at nodes of Ranvier, and NF155, the oligodendrocyte-specific isoform of neurofascin. Our in vitro studies with hippocampal slice cultures indicate that neurofascin antibodies inhibit axonal conduction in a complement-dependent manner. To evaluate whether circulating antineurofascin antibodies mediate a pathogenic effect in vivo, we cotransferred these antibodies with myelin oligodendrocyte glycoprotein-specific encephalitogenic T cells to mimic the inflammatory pathology of MS and breach the blood-brain barrier. In this animal model, antibodies to neurofascin selectively targeted nodes of Ranvier, resulting in deposition of complement, axonal injury, and disease exacerbation. Collectively, these results identify a novel mechanism of immune-mediated axonal injury that can contribute to axonal pathology in MS.

Notch1 and its ligand Jagged1 are present in remyelination in a T-cell- and antibody-mediated model of inflammatory demyelination.

The Notch receptor and its ligands are involved in myelination in central nervous system (CNS) development. Re-expression of this pathway in the adult CNS has been proposed to hamper remyelination in multiple sclerosis. Previous studies also revealed that pharmacological inhibition of Notch signaling ameliorates experimental autoimmune encephalomyelitis (EAE). However, in a recent study in toxin-induced demyelination constituents of the Notch signaling pathway were demonstrated in remyelinating lesions indicating that remyelination may occur in the presence of Notch signaling. We examined the expression of Notch1-immunoreactivity (IR) and Jagged1-IR in EAE induced by myelin-oligodendrocyte glycoprotein (MOG). In this model, the combined action of T cells, antibodies and the complement cascade yields a pathology closely reflecting multiple sclerosis. Notch1 and its ligand Jagged1 were differentially expressed in the lesions of MOG-EAE. Notch1-IR on macrophages was highest in actively demyelinating and lowest in remyelinating lesions. The amount of Notch1-positive astrocytes increased during the lesion evolution from demyelination to remyelination. Notch1-positive oligodendrocytes were exclusively present in remyelinating lesions and not found in lesions without signs of remyelination. Astrocytes represented the major source of Jagged1-IR in demyelination and remyelination. In conclusion, our study proves that constituents of the Notch pathway are expressed in remyelination in an animal model of T-cell- and antibody-mediated CNS demyelination. Thus, it is unlikely, at least in the paradigm of MOG-EAE, that Notch signaling is responsible for a failure of remyelination.

Cortical demyelination can be modeled in specific rat models of autoimmune encephalomyelitis and is major histocompatibility complex (MHC) haplotype-related.

In recent years, a number of histopathologic studies revealed the presence of cortical demyelination in multiple sclerosis (MS). The underlying mechanisms responsible for cortical demyelination are unresolved. Recently, the presence of cortical lesions in autoimmune encephalomyelitis (EAE) induced in marmosets and Lewis rats has been demonstrated. So far, it is not known whether cortical demyelinated lesions are also present in other models of EAE. In this study, we analyzed a large spectrum of different rat strains actively immunized with myelin oligodendrocyte glycoprotein (MOG), a model strongly mimicking MS for cortical demyelination. By using sets of rat strains with the constant EAE-permissive LEW nonmajor histocompatability complex (MHC) genome, but different MHC haplotypes, we demonstrated that considerable cortical demyelination was only found in LEW.1AR1 (RT1) and LEW.1W (RT1) strains. These rat strains have the isotypes and alleles RT1.BD in the MHC II region and RT1.C in the nonclassic MHC I region in common. Because cortical demyelination was most prominent in LEW.1AR1 rats, an additional strong influence is promoted by the RT1.A MHC class I allele. Demyelination was accompanied by microglia infiltration and deposition of immunoglobulins on myelin sheaths. Our study shows that extensive cortical demyelination can be reproducibly induced in certain rat strains by active immunization with MOG. Furthermore, our findings suggest that cortical demyelination in EAE depends on particular combinations of MHC I and class II isotypes and alleles. The mechanisms for this influence and any similar effects in humans will be important to define.

Effects of glatiramer acetate and interferon-beta on neurodegeneration in a model of multiple sclerosis: a comparative study.

Axonal destruction and neuronal loss occur early during multiple sclerosis (MS), an autoimmune inflammatory central nervous system disease that frequently manifests with acute optic neuritis. Glatiramer acetate (GA) and interferon-beta-1b (IFN-beta-1b) are two immunomodulatory agents that have been shown to decrease the frequency of MS relapses. However, the question of whether these substances can slow neurodegeneration in MS patients is the subject of controversy. In a rat model of experimental autoimmune encephalomyelitis, we investigated the effects of GA and IFN-beta-1b on the survival of retinal ganglion cells (RGCs), the neurons that form the axons of the optic nerve. For each substance, therapy was started 14 days before immunization, on the day of immunization, or on the day of clinical disease onset. After myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis became clinically manifest, optic neuritis was monitored by recording visual evoked potentials. The function of RGCs was measured by electroretinograms. Although early GA or IFN-beta-1b treatment showed benefit on disease activity, only treatment with GA exerted protective effects on RGCs, as revealed by measuring neurodegeneration and neuronal function. Furthermore, we demonstrate that this GA-induced neuroprotection does not exclusively depend on the reduction of inflammatory infiltrates within the optic nerve.

Differential expression of sonic hedgehog immunoreactivity during lesion evolution in autoimmune encephalomyelitis.

The signaling molecule Sonic hedgehog (Shh) is involved in several processes of central nervous system development. Recent reports indicate that Shh expression plays a role also in certain pathologic conditions in the adult brain, including multiple sclerosis and its animal model. However, the role of Shh signaling in immune-mediated demyelinating disease remains still uncertain. The aim of our study was to investigate the distribution pattern of Shh immunoreactivity (Shh-IR) during lesion evolution in myelin-oligodendrocyte-glycoprotein-induced experimental autoimmune encephalomyelitis (MOG-EAE), a model strongly mimicking multiple sclerosis. MOG-EAE was actively induced in DA rats. Histologic evaluation was performed with light and confocal microscopy on paraffin-embedded central nervous system sections from days 20 to 120 after active immunization. Shh-IR was present within the lesions of MOG-EAE during all stages of lesion evolution. The highest staining intensity for Shh was found in remyelinating lesions. In actively demyelinating, inactive demyelinated lesions, and in remyelinating lesions, Shh-IR was detected in macrophages, endothelium, and astrocytes. Shh-IR in axons was exclusively present in remyelinating lesions. Although the exact molecular mechanisms of the Shh-signaling pathway in experimental autoimmune encephalomyelitis are yet to be determined, our findings may imply a role of Shh signaling in facilitating remyelination.

Ciliary neurotrophic factor protects retinal ganglion cells from secondary cell death during acute autoimmune optic neuritis in rats.

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS which leads to demyelination, axonal destruction and neuronal loss in the early stages. Available therapies mainly target the inflammatory component of the disease but fail to prevent neurodegeneration. To investigate the effect of ciliary neurotrophic factor (CNTF) on the survival of retinal ganglion cells (RGCs), the neurons that form the axons of the optic nerve, we used a rat model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. Optic neuritis in this model was diagnosed by recording visual evoked potentials, and RGC function was monitored by measuring electroretinograms. This study demonstrates that CNTF has a neuroprotective effect on affected RGCs during acute optic neuritis. Furthermore, we demonstrate that CNTF exerts its neuroprotective effect through activation of the Janus kinase/signal transducer and activator of transcription pathway, mitogen activated protein kinases and a shift in the Bcl-2 family of proteins towards the anti-apoptotic side. In summary, our results demonstrate that CNTF can serve as an effective neuroprotective treatment in a rat model of MS that especially reflects the neurodegenerative aspects of this disease.

MHC class II isotype- and allele-specific attenuation of experimental autoimmune encephalomyelitis.

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.

Mechanisms and time course of neuronal degeneration in experimental autoimmune encephalomyelitis.

Neuronal and axonal damage is considered to be the main cause for long-term disability in multiple sclerosis. We analyzed the mechanism and kinetics of neuronal cell death in experimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte glycoprotein (MOG) by combining an electrophysiological in vivo assessment of the optic pathway with the investigation of retinal ganglion cell (RGC) counts. In accordance with our previous findings in this animal model, neuritis of the optic nerve (ON) leads to apoptotic RGC death. By further investigating the time course of RGC apoptosis in the present study, we found that neuronal cell death together with decreased visual acuity values occurred before the onset of clinical symptoms. Simultaneously with the time course of RGC apoptosis, we found a down-regulation of phospho-Akt as well as a shift in the relation of 2 proteins of the Bcl-2 family, Bax and Bcl-2, towards a more proapoptotic ratio in these cells. Comparing the kinetics and mechanisms of RGC death during MOG-EAE with those following complete surgical transection of the ON, we found significant agreement. We hypothesize that the main reason for RGC loss in MOG-EAE is the inflammatory attack but RGC death also occurs independently of histopathological ON changes.