Interferon-beta inhibits progression of relapsing-remitting experimental autoimmune encephalomyelitis

Prophylactic or therapeutic administration of Holarrhena floribunda hydro ethanol extract suppresses complete Freund's adjuvant-induced arthritis in Sprague-Dawley rats

BACKGROUND

A hydro ethanol extract of the stem bark of Holarrhena floribunda (HFE) has been shown to be effective in the management of acute inflammation. This study was to evaluate usefulness of the extract for the management of chronic inflammation in a murine model.

METHODS

Arthritis was induced in Sprague-Dawley rats using Complete Freund's Adjuvant. Anti-arthritic effect of the extract was evaluated in prophylactic and therapeutic treatment models at doses of 50, 200 and 500 mg/kg. Parameters assessed included oedema, serology of inflammatory response, bone tissue histology and haematology. Data were analysed by ANOVA and Tukey's multiple comparisons post hoc test.

RESULTS

HFE at 50-500 mg/kg dose-dependently [P ≥ 0.0354 (prophylactic) and P ≥ 0.0001 (therapeutic) inhibited swelling of the injected paw upon prophylactic [≤ 81.26% (P < 0.0001) or therapeutic [≤ 67.92% (P < 0.01) administration - and prevented spread of arthritis to the contralateral paw. The inflammation alleviation activity was further demonstrated by decrease in arthritis score, radiologic score and erythrocyte sedimentation rate. HFE at all doses significantly reduced serum interleukin (IL)-1α (P < 0.0197), and 500 mg/kg HFE reduced IL-6 (P = 0.0032). In contrast, serum concentrations of IL-10, protein kinase A and cyclic adenosine monophosphate were enhanced (P ≤ 0.0436). HFE consistently showed better prophylactic than therapeutic activity.

CONCLUSION

HFE strongly suppressed Complete Freund's Adjuvant-induced arthritis and modulated regulators of inflammation, including IL-1α, - 6 and - 10. Taken together, the data suggest that HFE has potential for use as an agent for modulation of the inflammatory response.

MicroRNA-124 acts as a positive regulator of IFN-β signaling in the lipopolysaccharide-stimulated human microglial cells

miR-124 is ubiquitously expressed in the nervous tissue and acts as a negative regulator of neuroinflammation. In the present study, we analyzed the possible role of miR-124 in response to LPS in the human microglial cell line. Our data revealed that the miR-124 anti-inflammatory effect is based not only on the suppression of MyD88 - NFκB pathway and downregulation of pro-inflammatory cytokines IL-1β and IL-6 but also on the enhancement of TRAM-TRIF signaling and increased IFN-β expression. Furthermore, the NFκB reporter assay demonstrated that specific miR-124 - induced NFκB activity changes could be detected only using NFκB reporter promoters lacking ATF/CREB binding site.

A STAT3 inhibitor ameliorates CNS autoimmunity by restoring Teff:Treg balance

Reestablishing an appropriate balance between T effector cells (Teff) and Tregs is essential for correcting autoimmunity. Multiple sclerosis (MS) is an immune-mediated chronic CNS disease characterized by neuroinflammation, demyelination, and neuronal degeneration, in which the Teff:Treg balance is skewed toward pathogenic Teffs Th1 and Th17 cells. STAT3 is a key regulator of Teff:Treg balance. Using the structure-based design, we have developed a potentially novel small-molecule prodrug LLL12b that specifically inhibits STAT3 and suppresses Th17 differentiation and expansion. Moreover, LLL12b regulates the fate decision between Th17 and Tregs in an inflammatory environment, shifting Th17:Treg balance toward Tregs and favoring the resolution of inflammation. Therapeutic administration of LLL12b after disease onset significantly suppresses disease progression in adoptively transferred, chronic, and relapsing-remitting experimental autoimmune encephalomyelitis. Disease relapses were also significantly suppressed by LLL12b given during the remission phase. Additionally, LLL12b shifts Th17:Treg balance of CD4⁺ T cells from MS patients toward Tregs and increases Teff sensitivity to Treg-mediated suppression. These data suggest that selective inhibition of STAT3 by the small molecule LLL12b recalibrates the effector and regulatory arms of CD4⁺ T responses, representing a potentially clinically translatable therapeutic strategy for MS.

Human Commensal Prevotella histicola Ameliorates Disease as Effectively as Interferon-Beta in the Experimental Autoimmune Encephalomyelitis

Gut microbiota has emerged as an important environmental factor in the pathobiology of multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). Both genetic and environmental factors have been shown to play an important role in MS. Among genetic factors, the human leukocyte antigen (HLA) class II allele such as HLA-DR2, DR3, DR4, DQ6, and DQ8 show the association with the MS. We have previously used transgenic mice expressing MS susceptible HLA class II allele such as HLA-DR2, DR3, DQ6, and DQ8 to validate significance of HLA alleles in MS. Although environmental factors contribute to 2/3 of MS risk, less is known about them. Gut microbiota is emerging as an imporatnt environmental factor in MS pathogenesis. We and others have shown that MS patients have distinct gut microbiota compared to healthy control (HC) with a lower abundance of Prevotella. Additionally, the abundance of Prevotella increased in patients receiving disease-modifying therapies (DMTs) such as Copaxone and/or Interferon-beta (IFNβ). We have previously identified a specific strain of Prevotella (Prevotella histicola), which can suppress experimental autoimmune encephalomyelitis (EAE) disease in HLA-DR3.DQ8 transgenic mice. Since Interferon-β-1b [IFNβ (Betaseron)] is a major DMTs used in MS patients, we hypothesized that treatment with the combination of P. histicola and IFNβ would have an additive effect on the disease suppression. We observed that treatment with P. histicola suppressed disease as effectively as IFNβ. Surprisingly, the combination of P. histicola and IFNβ was not more effective than either treatment alone. P. histicola alone or in combination with IFNβ increased the frequency and number of CD4+FoxP3+ regulatory T cells in the gut-associated lymphoid tissue (GALT). Treatment with P. histicola alone, IFNβ alone, and in the combination decreased frequency of pro-inflammatory IFN-γ and IL17-producing CD4+ T cells in the CNS. Additionally, P. histicola alone or IFNβ alone or the combination treatments decreased CNS pathology, characterized by reduced microglia and astrocytic activation. In conclusion, our study indicates that the human gut commensal P. histicola can suppress disease as effectively as commonly used MS drug IFNβ and may provide an alternative treatment option for MS patients.

Anti-inflammatory and cognitive effects of interferon-β1a (IFNβ1a) in a rat model of Alzheimer's disease

Background

Aβ_1-42 peptide abnormal production is associated with the development and maintenance of neuroinflammation and oxidative stress in brains from Alzheimer disease (AD) patients. Suppression of neuroinflammation may then represent a suitable therapeutic target in AD. We evaluated the efficacy of IFNβ1a in attenuating cognitive impairment and inflammation in an animal model of AD.

Methods

A rat model of AD was obtained by intra-hippocampal injection of Aβ_1-42 peptide (23 μg/2 μl). After 6 days, 3.6 μg of IFNβ1a was given subcutaneously (s.c.) for 12 days. Using the novel object recognition (NOR) test, we evaluated changes in cognitive function. Measurement of pro-inflammatory or anti-inflammatory cytokines, reactive oxygen species (ROS), and SOD activity levels was performed in the hippocampus. Data were evaluated by one-way ANOVA with Fisher’s Protected Least Significant Difference (PLSD) test.

Results

We showed that treatment with IFNβ1a was able to reverse memory impairment and to counteract microglia activation and upregulation of pro-inflammatory cytokines (IL-6, IL-1β) in the hippocampus of Aβ_1-42-injected rats. The anti-inflammatory cytokine IL-10, significantly reduced in the Aβ_1-42 animals, recovered to control levels following IFNβ1a treatment. IFNβ1a also reduced ROS and lipids peroxidation and increased SOD1 protein levels in the hippocampus of Aβ_1-42-injected rats.

Conclusion

This study shows that IFNβ1a is able to reverse the inflammatory and cognitive effects of intra-hippocampal Aβ_1-42 in the rat. Given the role played by inflammation in AD pathogenesis and the established efficacy of IFNβ1a in the treatment of inflammatory diseases of the central nervous system such as multiple sclerosis, its use may be a viable strategy to inhibit the pro-inflammatory cytokine and oxidative stress cascade associated with Aβ deposition in the hippocampus of AD patients.

Emerging Role of Follicular T Helper Cells in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disorder where both T cells and B cells are implicated in pathology. However, it remains unclear how these two distinct populations cooperate to drive disease. There is ample evidence from studies in both MS patients and mouse models that Th17, B cells, and follicular T helper (TFH) cells contribute to disease. This review article describes the literature that identifies mechanisms by which Th17, TFH, and B cells cooperatively drive disease activity in MS and experimental autoimmune encephalomyelitis (EAE). The curation of this literature has identified that central nervous system (CNS) infiltrating TFH cells act with TH17 cell to contribute to an inflammatory B cell response in neuroinflammation. This demonstrates that TFH cells and their products are promising targets for therapies in MS.

Animal models of multiple sclerosis: From rodents to zebrafish

Multiple sclerosis (MS) is a chronic, immune-mediated demyelinating disease of the central nervous system. Animal models of MS have been critical for elucidating MS pathological mechanisms and how they may be targeted for therapeutic intervention. Here we review the most commonly used animal models of MS. Although these animal models cannot fully replicate the MS disease course, a number of models have been developed to recapitulate certain stages. Experimental autoimmune encephalomyelitis (EAE) has been used to explore neuroinflammatory mechanisms and toxin-induced demyelinating models to further our understanding of oligodendrocyte biology, demyelination and remyelination. Zebrafish models of MS are emerging as a useful research tool to validate potential therapeutic candidates due to their rapid development and amenability to genetic manipulation.

Use of interferon beta in multiple sclerosis: rationale for early treatment and evidence for dose- and frequency-dependent effects on clinical response

The current approach to the use of interferon (IFN) beta in the treatment of multiple sclerosis (MS) is, in general, conservative. However, recent findings about early events in MS and data on dose-response relationships with IFN beta indicate that such an approach may be suboptimal. Four lines of evidence suggest that delays in the initiation of therapy with IFN beta may be detrimental: I) axonal damage secondary to inflammation starts very early in the course of MS; 2) pathological events occurring early in MS are predictive of the future course of the disease; 3) inflammatory activity in relapsing MS is not confined to episodes of clinical impairment, but often starts before the first such episode and generally continues during remissions; and 4) the immune-mediated activity that underlies MS may become more difficult to control as the disease progresses. An early treatment strategy is also supported by data from two recently published clinical studies. In addition, preclinical and clinical results suggest that the beneficial effects of IFN may be dose- and frequency-dependent Taken together, these findings indicate that treatment with IFN beta should be started as early as possible in the course of MS, and suggest that, in order to maximize patient benefit, the highest possible dose of IFN beta should be chosen. Multiple Sclerosis (2002) 8, 2-9

Interferon-β regulates dendritic cell activation and migration in experimental autoimmune encephalomyelitis

CD11c⁺ dendritic cells (DCs) exert a critical role as antigen-presenting cells in regulating pathogenic T cells in multiple sclerosis (MS). To determine whether the therapeutic benefit of interferon-β (IFN-β) treatment for MS is in part influenced by IFN regulation of DC function, we examined the immunophenotype of DCs derived from IFN-β^+/+ and IFN-β^-/- mice using a myelin oligodendrocyte glycoprotein (MOG) peptide-induced mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Our earlier work identified that IFN-β^-/- mice exhibit earlier onset and more rapid progression of neurological impairment compared with IFN-β^+/+ mice. In this study we show that lipopolysaccharide-/MOG peptide-stimulated IFN-β^-/- DCs secrete cytokines associated with pathological T helper type 17 rather than regulatory T-cell polarization and exhibit increased CD80 and MHCII expression when compared with stimulated IFN-β^+/+ DCs. IFN-β^-/- DCs from mice immunized to develop EAE induce greater proliferation of MOG-transgenic CD4⁺ T cells and promote interleukin-17 production by these T cells. Adoptive transfer of MOG peptide-primed IFN-β^-/- DCs into IFN-β^+/+ and IFN-β^-/- mice immunized to develop EAE resulted in their rapid migration into the central nervous system of recipient mice, before onset of disease, which we attribute to failed signal transducer and activator of transcription 1-mediated inhibition of CCR7. Taken together, our data support immunoregulatory roles for IFN-β in the activation and migration of DCs during EAE.

IFN-β Facilitates Neuroantigen-Dependent Induction of CD25+ FOXP3+ Regulatory T Cells That Suppress Experimental Autoimmune Encephalomyelitis

This study introduces a flexible format for tolerogenic vaccination that incorporates IFN-β and neuroantigen (NAg) in the Alum adjuvant. Tolerogenic vaccination required all three components, IFN-β, NAg, and Alum, for inhibition of experimental autoimmune encephalomyelitis (EAE) and induction of tolerance. Vaccination with IFN-β + NAg in Alum ameliorated NAg-specific sensitization and inhibited EAE in C57BL/6 mice in pretreatment and therapeutic regimens. Tolerance induction was specific for the tolerogenic vaccine Ag PLP178-191 or myelin oligodendrocyte glycoprotein (MOG)35-55 in proteolipid protein- and MOG-induced models of EAE, respectively, and was abrogated by pretreatment with a depleting anti-CD25 mAb. IFN-β/Alum-based vaccination exhibited hallmarks of infectious tolerance, because IFN-β + OVA in Alum-specific vaccination inhibited EAE elicited by OVA + MOG in CFA but not EAE elicited by MOG in CFA. IFN-β + NAg in Alum vaccination elicited elevated numbers and percentages of FOXP3+ T cells in blood and secondary lymphoid organs in 2D2 MOG-specific transgenic mice, and repeated boosters facilitated generation of activated CD44high CD25+ regulatory T cell (Treg) populations. IFN-β and MOG35-55 elicited suppressive FOXP3+ Tregs in vitro in the absence of Alum via a mechanism that was neutralized by anti-TGF-β and that resulted in the induction of an effector CD69+ CTLA-4+ IFNAR+ FOXP3+ Treg subset. In vitro IFN-β + MOG-induced Tregs inhibited EAE when transferred into actively challenged recipients. Unlike IFN-β + NAg in Alum vaccines, vaccination with TGF-β + MOG35-55 in Alum did not increase Treg percentages in vivo. Overall, this study indicates that IFN-β + NAg in Alum vaccination elicits NAg-specific, suppressive CD25+ Tregs that inhibit CNS autoimmune disease. Thus, IFN-β has the activity spectrum that drives selective responses of suppressive FOXP3+ Tregs.

Quantitative Evaluation of Leukocyte Infiltration into the Spinal Cord in a Model of Experimental Autoimmune Encephalomyelitis: Statistical-Analytical Techniques for Use in Evaluating Drugs

Experimental autoimmune encephalomyelitis (EAE) is considered a useful animal model for preclinical development of drugs to treat human multiple sclerosis. The relationship between clinical disease signs and leukocyte infiltration into the lower spinal cord was studied in EAE in order to assess analytical and statistical methods for evaluating drug candidates. As expected, the degree of clinical disease was correlated with the amount of leukocyte infiltration into the lower spinal cord. Additionally, we were able to distinguish patterns of clinical signs and leukocyte infiltration for classes of recurring-remitting and progressive forms of the disease. The distributions of leukocyte infiltration sites correspond to negative binomial distributions, and the parameters calculated from the respective distributions differ significantly among disease classes. We determined the sensitivity of histological measures of the leukocyte infiltration and calculated the magnitude of differences required in order to observe statistically significant changes in leukocyte infiltration. Using immunohistochemistry to assess cell surface markers of leukocytes in the lower spinal cord, we measured the infiltration of CD4+ and CD8+ lymphocytes and cells of the macrophage/microglial lineage stained with the monoclonal antibody, F4/80. Treatment with an anti-4 integrin monoclonal antibody, PS/2, served as an indicator of how we may expect to measure the effects of new pharmaceutical agents tested using our particular model of EAE. PS/2 treatment affected clinical signs of disease only when administered very early in the time course of the disease, despite a marked statistically significant decline in CD4+ cells regardless of when the PS/2 was administered. The analytical and statistical techniques applied here may be used to design efficient and sensitive assays for the evaluation of new drugs that may prove useful in the treatment of multiple sclerosis.

Differential effects of IFN-β on IL-12, IL-23, and IL-10 expression in TLR-stimulated dendritic cells

MS is an autoimmune disease characterized by immune cell infiltration in the CNS, leading to cumulative disability. IFN-β, used clinically in RR-MS reduces lesion formation and rates of relapse. Although the molecular mechanisms are not entirely elucidated, myeloid cells appear to be a major target for the therapeutic effects of IFN-β. DCs have a critical role in experimental models of MS through their effect on encephalitogenic Th1/Th17 cell differentiation and expansion. Here we focused on the effects of IFN-β on DC expression of cytokines involved in the control of Th1/Th17 differentiation and expansion. Administration of IFN-β to mice immunized with MOG35-55 inhibited IL-12 and IL-23 expression in splenic DC and reduced in vivo differentiation of Th1/Th17 cells. IFN-β affected cytokine expression in TLR-stimulated DC in a similar manner in vitro, inhibiting IL-12 and IL-23 and stimulating IL-10 at both mRNA and protein levels, by signaling through IFNAR. We investigated the role of the signaling molecules STAT1/STAT2, IRF-1 and IRF-7, and of the PI3K→GSK3 pathway. IFN-β inhibition of the IL-12 subunits p40 and p35 was mediated through STAT1/STAT2, whereas inhibition of IL-23 was STAT1 dependent, and the stimulatory effect on IL-10 expression was mediated through STAT2. IFN-β induces IRF-7 and, to a lesser degree, IRF-1. However, neither IRF mediated the effects of IFN-β on IL-12, IL-23, or IL-10. We found that the PI3K pathway mediated IL-12 inhibition but did not interfere with the inhibition of IL-23 or stimulation of IL-10.

The conundrum of interferon-β non-responsiveness in relapsing-remitting multiple sclerosis

A series of controlled clinical trials have shown that exogenous interferon-beta (IFN-β) benefits patients with relapsing-remitting multiple sclerosis (RRMS) by reducing relapse rate, disability progression, and the formation of new brain and spinal cord lesions on magnetic resonance imaging (MRI) scans. Unfortunately, however, the effectiveness of IFN-β is limited in this setting by the occurrence of treatment non-responsiveness in nearly 25% of patients. Furthermore, clinicians who care for RRMS patients remain unable to accurately identify IFN-β non-responders prior to the initiation of therapy, causing delays in the use of alternative treatments and sometimes requiring that patients turn to medications with more significant side effects to control their disease. Progress has been made toward understanding how both endogenous and exogenous IFN-β act to slow RRMS as well as the related mouse model, experimental autoimmune encephalomyelitis (EAE). Most studies point to its inhibitory actions on circulating immune cells as being important for suppressing both disorders, but multiple potential target cells and inflammatory pathways have been implicated and those essential to confer its benefits remain undefined. This review focuses on the role of both endogenous and exogenous IFN-β in RRMS, paying particular attention to the issue of why certain individuals appear refractory to its disease-modifying effects. A continued goal in this field remains the identification of a convenient biomarker that accurately predicts IFN-β treatment non-responsiveness in individual RRMS patients. Development of such an assay will allow clinicians to customize therapy for patients with this complex disorder.

Astrocyte CCL2 sustains immune cell infiltration in chronic experimental autoimmune encephalomyelitis

Chemokine (C-C motif) ligand 2 (CCL2), initially identified as monocyte chemoattractant protein-1 (MCP-1), recruits immune cells to the central nervous system (CNS) during autoimmune inflammation. CCL2 can be expressed by multiple cell types, but which cells are responsible for CCL2 function during acute and chronic phases of autoimmune disease is not known. We determined the role of CCL2 in astrocytes in vivo during experimental autoimmune encephalomyelitis (EAE) by using Cre-loxP gene deletion. Mice with a conditional gene deletion of CCL2 from astrocytes had less severe EAE late in disease while having a similar incidence and severity of disease at onset as compared to wild type (WT) control littermates. EAE mice devoid of CCL2 in astrocytes had less macrophage and T cell inflammation in the white matter of the spinal cord and less diffuse activation of astrocytes and microglia in both white and gray matter as well as less axonal loss and demyelination, compared to WT littermates. These findings demonstrate that CCL2 in astrocytes plays an important role in the continued recruitment of immune cells and activation of glial cells in the CNS during chronic EAE, thereby suggesting a novel cell specific target for neuroprotective treatments of chronic neuroinflammatory diseases.

Neuroprotective dimethyl fumarate synergizes with immunomodulatory interferon beta to provide enhanced axon protection in autoimmune neuroinflammation

INTRODUCTION

Despite recent advances in development of treatments for multiple sclerosis, there is still an unmet need for more effective and also safe therapies. Based on the modes of action of interferon-beta (IFN-β) and dimethyl fumarate (DMF), we hypothesized that anti-inflammatory and neuroprotective effects may synergize in experimental autoimmune encephalomyelitis (EAE).

METHODS

EAE was induced in C57BL/6 mice by immunization with MOG35-55-peptide. Murine IFN-β was injected s.c. every other day at 10.000IU, and DMF was provided at 15mg/kg by oral gavage twice daily. Control mice received PBS injections and were treated by oral gavage with the vehicle methylcellulose. Mice were scored daily by blinded observers and histological, FACS and cytokine studies were performed to further elucidate the underlying mechanism of action.

RESULTS

Combination therapy significantly ameliorated EAE disease course in comparison to controls and monotherapy with IFN-β. Histological analyses showed a significant effect on axon preservation with almost twice as much axons present in inflamed lesions as compared to control. Remarkably, the effect on axonal preservation was more pronounced under combination therapy than with both monotherapies. Neither monotherapy nor combination therapy demonstrated modulation of cytokines and frequency of antigen presenting cells.

DISCUSSION

Combination of IFN-β and DMF resulted in greater beneficial effects with improved tissue protection as compared to the respective monotherapies. Further combination studies of these safe therapies in human disease are warranted.

The experimental autoimmune encephalomyelitis (EAE) model of MS: utility for understanding disease pathophysiology and treatment

While no single model can exactly recapitulate all aspects of multiple sclerosis (MS), animal models are essential in understanding the induction and pathogenesis of the disease and to develop therapeutic strategies that limit disease progression and eventually lead to effective treatments for the human disease. Several different models of MS exist, but by far the best understood and most commonly used is the rodent model of experimental autoimmune encephalomyelitis (EAE). This model is typically induced by either active immunization with myelin-derived proteins or peptides in adjuvant or by passive transfer of activated myelin-specific CD4+ T lymphocytes. Mouse models are most frequently used because of the inbred genotype of laboratory mice, their rapid breeding capacity, the ease of genetic manipulation, and availability of transgenic and knockout mice to facilitate mechanistic studies. Although not all therapeutic strategies for MS have been developed in EAE, all of the current US Food and Drug Administration (FDA)-approved immunomodulatory drugs are effective to some degree in treating EAE, a strong indicator that EAE is an extremely useful model to study potential treatments for MS. Several therapies, such as glatiramer acetate (GA: Copaxone), and natalizumab (Tysabri), were tested first in the mouse model of EAE and then went on to clinical trials. Here we discuss the usefulness of the EAE model in understanding basic disease pathophysiology and developing treatments for MS as well as the potential drawbacks of this model.

Independent and interdependent immunoregulatory effects of IL-27, IFN-β, and IL-10 in the suppression of human Th17 cells and murine experimental autoimmune encephalomyelitis

IFN-β, IL-27, and IL-10 have been shown to exert a range of similar immunoregulatory effects in murine and human experimental systems, particularly in Th1- and Th17-mediated models of autoimmune inflammatory disease. In this study we sought to translate some of our previous findings in murine systems to human in vitro models and delineate the interdependence of these different cytokines in their immunoregulatory effects. We demonstrate that human IL-27 upregulates IL-10 in T cell-activated PBMC cultures and that IFN-β drives IL-27 production in activated monocytes. IFN-β-driven IL-27 is responsible for the upregulation of IL-10, but not IL-17 suppression, by IFN-β in human PBMCs. Surprisingly, IL-10 is not required for the suppression of IL-17 by either IL-27 or IFN-β in this model or in de novo differentiating Th17 cells, nor is IL-27 signaling required for the suppression of experimental autoimmune encephalomyelitis (EAE) by IFN-β in vivo. Furthermore, and even more surprisingly, IL-10 is not required for the suppression of Th17-biased EAE by IL-27, in sharp contrast to Th1-biased EAE. In conclusion, IFN-β and IL-27 both induce human IL-10, both suppress human Th17 responses, and both suppress murine EAE. However, IL-27 signaling is not required for the therapeutic effect of IFN-β in EAE. Suppression of Th17-biased EAE by IL-27 is IL-10-independent, in contrast to its mechanism of action in Th1-biased EAE. Taken together, these findings delineate a complex set of interdependent and independent immunoregulatory mechanisms of IFN-β, IL-27, and IL-10 in human experimental models and in murine Th1- and Th17-driven autoimmunity.

The development of myelin repair agents for treatment of multiple sclerosis: progress and challenges

Multiple Sclerosis (MS) is an inflammatory demyelinating disorder which affects the central nervous system. Multiple sclerosis treatment has traditionally focused on preventing inflammatory damage to the myelin sheath. Indeed, all currently available disease modifying agents are immunomodulators. However, the limitations of this approach are becoming increasingly clear, leading to the exploration of other potential therapeutic strategies. In particular, targeting the endogenous remyelination system to promote replacement of the lost myelin sheath has shown much promise. As our understanding of remyelination biology advances, the realization of a remyelinating therapeutic comes closer to fruition. In our review, we aim to summarize the limitations of the current immune focused treatment strategy and discuss the potential of remyelination as a new treatment method. Finally, we aim to highlight the challenges in the identification and development of such therapeutics.

Type I IFN-mediated regulation of IL-1 production in inflammatory disorders

Although contributing to inflammatory responses and to the development of certain autoimmune pathologies, type I interferons (IFNs) are used for the treatment of viral, malignant, and even inflammatory diseases. Interleukin-1 (IL-1) is a strongly pyrogenic cytokine and its importance in the development of several inflammatory diseases is clearly established. While the therapeutic use of IL-1 blocking agents is particularly successful in the treatment of innate-driven inflammatory disorders, IFN treatment has mostly been appreciated in the management of multiple sclerosis. Interestingly, type I IFNs exert multifaceted immunomodulatory effects, including the reduction of IL-1 production, an outcome that could contribute to its efficacy in the treatment of inflammatory diseases. In this review, we summarize the current knowledge on IL-1 and IFN effects in different inflammatory disorders, the influence of IFNs on IL-1 production, and discuss possible therapeutic avenues based on these observations.

Experimental autoimmune encephalomyelitis (EAE) as a model for multiple sclerosis (MS)

Experimental autoimmune encephalomyelitis (EAE) is the most commonly used experimental model for the human inflammatory demyelinating disease, multiple sclerosis (MS). EAE is a complex condition in which the interaction between a variety of immunopathological and neuropathological mechanisms leads to an approximation of the key pathological features of MS: inflammation, demyelination, axonal loss and gliosis. The counter-regulatory mechanisms of resolution of inflammation and remyelination also occur in EAE, which, therefore can also serve as a model for these processes. Moreover, EAE is often used as a model of cell-mediated organ-specific autoimmune conditions in general. EAE has a complex neuropharmacology, and many of the drugs that are in current or imminent use in MS have been developed, tested or validated on the basis of EAE studies. There is great heterogeneity in the susceptibility to the induction, the method of induction and the response to various immunological or neuropharmacological interventions, many of which are reviewed here. This makes EAE a very versatile system to use in translational neuro- and immunopharmacology, but the model needs to be tailored to the scientific question being asked. While creating difficulties and underscoring the inherent weaknesses of this model of MS in straightforward translation from EAE to the human disease, this variability also creates an opportunity to explore multiple facets of the immune and neural mechanisms of immune-mediated neuroinflammation and demyelination as well as intrinsic protective mechanisms. This allows the eventual development and preclinical testing of a wide range of potential therapeutic interventions.

Role of interleukin 10 transcriptional regulation in inflammation and autoimmune disease

Interleukin 10 (IL-10) is a cytokine with potent anti-inflammatory properties that plays a central role in limiting host immune response to pathogens, thereby preventing damage to the host and maintaining normal tissue homeostasis. Dysregulation of IL-10 is associated with enhanced immunopathology in response to infection as well as increased risk for development of many autoimmune diseases. Thus a fundamental understanding of IL-10 gene expression is critical for our comprehension of disease progression and resolution of host inflammatory response. In this review, we discuss modes of regulation of IL-10 gene expression in immune effector cell types, including signal transduction, epigenetics, promoter architecture, and post-transcriptional regulation, and how aberrant regulation contributes to immunopathology and disease progression.

Type I IFN promotes IL-10 production from T cells to suppress Th17 cells and Th17-associated autoimmune inflammation

Whereas the immune system is essential for host defense against pathogen infection or endogenous danger signals, dysregulated innate and adaptive immune cells may facilitate harmful inflammatory or autoimmune responses. In the CNS, chronic inflammation plays an important role in the pathogenesis of neurodegenerative diseases such as multiple sclerosis (MS). Our previous study has demonstrated a critical role for the type I IFN induction and signaling pathways in constraining Th17-mediated experimental autoimmune encephalomyelitis (EAE), an animal model of human MS. However, it remains unknown if self-reactive Th17 cells can be reprogrammed to have less encephalitogenic activities or even have regulatory effects through modulation of innate pathways. In this study, we investigated the direct effects of type I IFN on Th17 cells. Our data show that IFNβ treatment of T cells cultured under Th17 polarizing conditions resulted in reduced production of IL-17, but increased production of IL-10. We also found that IFNβ induced IL-10 production by antigen specific T cells derived from immunized mice. Furthermore, IFNβ treatment could suppress the encephalitogenic activity of myelin-specific T cells, and ameliorate clinical symptoms of EAE in an adoptive transfer model. Together, results from this study suggest that IFNβ may induce antigen-specific T cells to produce IL-10, which in turn negatively regulate Th17-mediate inflammatory and autoimmune response.

Insight into the mechanism of laquinimod action

Laquinimod is a small, novel, orally active, well-tolerated molecule that significantly reduced gadolinium-enhancing lesions in patients with multiple sclerosis (MS). Orally administered laquinimod was found to be present within the central nervous system (CNS) in both healthy mice and mice with experimental autoimmune encephalomyelitis (EAE). Laquinimod inhibits development of both acute and chronic EAE. Furthermore, laquinimod minimizes inflammation, demyelination and axonal damage in MOG-induced EAE in mice treated at disease induction and following clinical disease onset. In vitro, laquinimod down-regulates secretion of pro-inflammatory cytokines and enhances production of anti-inflammatory cytokines from peripheral blood mononuclear cells (PBMCs) derived from healthy subjects and untreated relapsing remitting (RR) MS patients. Additionally, patients treated with laquinimod demonstrate up-regulation of brain-derived neurotrophic factor (BDNF) in the serum. In conclusion, treatment with laquinimod is effective in reducing inflammation, demyelination and axonal damage.

Effects of human recombinant-interferon β in experimental autoimmune encephalomyelitis in guinea pigs

CONTEXT

Although clinical data for beneficial effects of Betaferon, human recombinant-interferon (r-IFN) β-1b, are accumulating, what is less evident is how and why it works.

OBJECTIVE

The present study was carried out to examine whether Betaferon suppresses progression of experimental autoimmune encephalomyelitis (EAE).

MATERIALS AND METHODS

The EAE model was employed in guinea pigs in vivo, and mononuclear cell proliferation and 2',5'-oligoadenylate synthetase activity were assessed in vitro.

RESULTS

Betaferon was more reactive in two assays of guinea pigs, mitogen-induced proliferation of peripheral blood mononuclear cells and 2',5'-oligoadenylate synthetase activity of blood, than in rats and rabbits. Guinea pigs were immunized actively by antigen, porcine myelin basic protein. The neurological deficits were assessed by clinical signs scored daily. Guinea pig Betaferon, replaced with guinea pig albumin (GPA), at 1.2 and 12.0 MIU/kg/day or vehicle was administered subcutaneously daily for 20 days in the immunized guinea pigs. GPA-Betaferon suppressed the manifestation of ataxia or more progression of chronic neurological deficits significantly at 1.2 MIU/kg (p <0.05). Two out of 10 animals manifested no clinical signs in the GPA-Betaferon-treated group with the higher dose, while all animals were worsened with typical clinical signs of EAE in the vehicle group where mononuclear cell infiltrates around blood vessels were seen in the spinal cord of vehicle-treated animals.

DISCUSSION AND CONCLUSION

Human r-IFN β-1b attenuates progression of neurological deficits in the EAE model of guinea pigs with evidence for higher susceptibility of animal cells/tissues to the human cytokine, in contrast with rodents and rabbits.

Myelin repair is accelerated by inactivating CXCR2 on nonhematopoietic cells

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS and remyelination in MS ultimately fails. Although strategies to promote myelin repair are eagerly sought, mechanisms underlying remyelination in vivo have been elusive. CXCR2 is expressed on neutrophils and oligodendrocyte lineage cells in the CNS. CXCR2-positive neutrophils facilitate inflammatory demyelination in demyelination models such as experimental autoimmune encephalomyelitis (EAE) and cuprizone intoxication. Systemic injection of a small molecule CXCR2 antagonist at the onset of EAE decreased demyelinated lesions. These results left the cellular target of the CXCR2 antagonist uncertain and did not clarify whether CXCR2 blockade prevented demyelination or promoted remyelination. Here, we show that the actions of CXCR2 on nonhematopoietic cells unexpectedly delay myelin repair. Bone marrow chimeric mice (Cxcr2(+/-)-->Cxcr2(-/-) and Cxcr2(+/-)-->Cxcr2(+/+)) were subjected to two distinct models of myelin injury. In all cases, myelin repair was more efficient in Cxcr2(+/-)-->Cxcr2(-/-) animals. Oligodendrocyte progenitor cells (OPCs) in demyelinated lesions of Cxcr2(+/-)-->Cxcr2(-/-) mice proliferated earlier and more vigorously than in tissues from Cxcr2(+/-)--> Cxcr2(+/+) animals. In vitro demyelinated CNS slice cultures also showed better myelin repair when CXCR2 was blocked with neutralizing antibodies or was genetically deleted. Our results suggest that CXCR2 inactivation permits optimal spatiotemporal positioning of OPCs in demyelinating lesions to receive local proliferative and differentiating signals. Given that CXCR2 exerts dual functions that promote demyelination and decrease remyelination by actions toward hematopoietic cells and nonhematopoietic cells, respectively, our findings identify CXCR2 as a promising drug target for clinical demyelinating disorders.

B-cell delivered gene therapy for tolerance induction: role of autoantigen-specific B cells

Antigen-specific tolerance induction using autologous B-cell gene therapy is a potential treatment to eliminate undesirable immune responses. For example, we have shown that experimental autoimmune encephalomyelitis (EAE) and type 1 diabetes in NOD mice can be ameliorated using antigen-Ig fusion protein transduced B cells. However, it is well established that auto-reactive antigen-specific B cells are activated in many autoimmune diseases and can contribute to pathogenesis. While syngeneic B cells from immunized or autoimmune mice can serve as tolerogenic antigen-presenting cells (APC), this observation begs the question of whether the antigen-specific B cells per se can be transduced as tolerogenic APC. To test this, we employed two model systems employing B cell receptor (BCR) transgenic or wild type (wt) mice as B-cell donors. While adoptively transferred MOG-Ig transduced wt C57Bl/6 B cells were highly tolerogenic and ameliorated EAE, MOG-Ig transduced anti-MOG B cells from BCR transgenic mice were not. This phenomenon was reproduced in the NOD diabetes model in which pro-insulin-Ig transduced polyclonal wt NOD B cells were protective, whereas similarly transduced anti-insulin BCR B cells were not. Since the frequency of antigen-specific B cells in an immunized animal is quite low, we wished to determine the threshold numbers of BCR transgenic B cells that could be present in an effective transduced population. Therefore, we "spiked" polyclonal wt C57Bl/6 B cells with different numbers of anti-MOG BCR transgenic B cells. In the EAE model, we found protection when BCR B cells were present at 1%, but they prevented tolerance induction at 10%. Antigen-specific B cells expressed normal levels of co-stimulatory molecules and were tolerogenic when transduced with an irrelevant antigen (OVA). Thus, the presence of a BCR specific for the target autoantigen may interfere with the tolerogenic process to that antigen, but BCR-specific B cells are not intrinsically defective as tolerogenic APC. Taken together, these data suggest that antigen-specific tolerance induction can be achieved in the presence of a limited number of antigen-specific B cells, but higher numbers of pathogenic B cells may mask this induction. This observation should guide future development of therapies using autologous B cells to treat patients with autoimmune diseases.

Mouse models for multiple sclerosis: historical facts and future implications

Multiple sclerosis (MS) is an inflammatory and demyelinating condition of the CNS, characterized by perivascular infiltrates composed largely of T lymphocytes and macrophages. Although the precise cause remains unknown, numerous avenues of research support the hypothesis that autoimmune mechanisms play a major role in the development of the disease. Pathologically similar lesions to those seen in MS can be induced in laboratory rodents by immunization with CNS-derived antigens. This form of disease induction, broadly termed experimental autoimmune encephalomyelitis, is frequently the starting point in MS research with respect to studying pathogenesis and creating novel treatments. Many different EAE models are available, each mimicking a particular facet of MS. These models all have common ancestry, and have developed from a single concept of immunization with self-antigen. We will discuss the major changes in immunology research, which have shaped the EAE models we use today, and discuss how current animal models of MS have resulted in successful treatments and more open questions for researchers to address.

Role of cytokines as mediators and regulators of microglial activity in inflammatory demyelination of the CNS

As the resident innate immune cells of the central nervous system (CNS), microglia fulfil a critical role in maintaining tissue homeostasis and in directing and eliciting molecular responses to CNS damage. The human disease Multiple Sclerosis and animal models of inflammatory demyelination are characterized by a complex interplay between degenerative and regenerative processes, many of which are regulated and mediated by microglia. Cellular communication between microglia and other neural and immune cells is controlled to a large extent by the activity of cytokines. Here we review the role of cytokines as mediators and regulators of microglial activity in inflammatory demyelination, highlighting their importance in potentiating cell damage, promoting neuroprotection and enhancing cellular repair in a context-dependent manner.

Experimental autoimmune encephalomyelitis in Lewis rats: IFN-beta acts as a tolerogenic adjuvant for induction of neuroantigen-dependent tolerance

Cytokine-Ag fusion proteins represent a novel approach for induction of Ag-specific tolerance and may constitute an efficient therapy for autoimmune disease. This study addressed whether a fusion protein containing rat IFN-beta and the encephalitogenic 73-87 determinant of myelin basic protein (i.e., the neuroantigen, or NAg) could prevent or treat experimental autoimmune encephalomyelitis (EAE) in Lewis rats. The optimal structure of the fusion protein was comprised of the rat IFN-beta cytokine as the N-terminal domain with an enterokinase (EK) linker to the NAg domain. Both cytokine and NAg domains had full biological activity. Subcutaneous administration of 1 nmol of IFNbeta-NAg fusion protein in saline on days -21, -14, and -7 before encephalitogenic challenge on day 0 resulted in a substantial attenuation of EAE. In contrast, administration of IFN-beta or NAg alone did not affect susceptibility to EAE. The covalent attachment of IFN-beta and NAg was not necessary, because separate injections of IFN-beta and NAg at adjacent sites were as effective as injection of IFNbeta-NAg for prevention of disease. When treatment was initiated after disease onset, the rank order of inhibitory activity was as follows: the IFNbeta-NAg fusion protein > or = a mixture of IFN-beta plus NAg > IFN-beta > NAg. The novel finding that IFN-beta acts as a tolerogenic adjuvant as well as a tolerogenic fusion partner may have significance for development of tolerogenic vaccines.

MHC class I upregulation is not sufficient to rescue neonatal alpha motoneurons after peripheral axotomy

Associated with neuronal death, profound synaptic changes occur in the spinal cord during the apoptotic process triggered after axotomy in neonatal rats. With respect to this, the major histocompatibility complex of class I (MHC class I) has recently emerged as a new mechanism related to synaptic stripping and plasticity. The present study investigated the impact of upregulating MHC class I expression by treatment with beta interferon (beta INF) on motoneuron survival, synaptic plasticity and astrogliosis after neonatal sciatic nerve injury. P2 rats were subjected to unilateral axotomy followed by three days of beta INF treatment. The results were analyzed by counting Nissl stained motoneurons, immunohistochemistry (anti-synaptophysin, MHC class I, GFAP and Iba-1) and transmission electron microscopy. INF treatment induced an increased expression of MHC class I, which resulted in a stronger synaptic elimination process in the spinal cord, as seen by the synaptophysin labeling. GFAP and Iba-1 upregulation were not significantly altered by the INF treatment, displaying the same degree of enhanced reactivity as compared to the placebo group. The ultrastructural analysis showed that, apart from the overall reduction of inputs in the neuropil, no statistical differences were present when comparing the INF and placebo treated animals. Also, neuronal survival was not altered by cytokine administration. The present results provide evidence that MHC class I upregulation after neonatal injury does not change the fate of lesioned motoneurons. In this way, the lack of neurotrophic support may cause broader synaptic loss, which superposes the more subtle effects of the upregulation of MHC class I.

Engagement of the type I interferon receptor on dendritic cells inhibits T helper 17 cell development: role of intracellular osteopontin

Mechanisms that prevent inappropriate or excessive interleukin-17-producing T helper (Th17) cell responses after microbial infection may be necessary to avoid autoimmunity. Here, we define a pathway initiated by engagement of type I IFN receptor (IFNAR) expressed by dendritic cells (DC) that culminated in suppression of Th17 cell differentiation. IFNAR-dependent inhibition of an intracellular translational isoform of Osteopontin, termed Opn-i, derepressed interleukin-27 (IL-27) secretion and prevented efficient Th17 responses. Moreover, Opn-i expression in DC and microglia regulated the type and intensity of experimental autoimmune encephalomyelitis (EAE). Mice containing DC deficient in Opn-i produced excessive amounts of IL-27 and developed a delayed disease characterized by an enhanced Th1 response compared with the dominant Th17 response of Opn-sufficient mice. Definition of the IFNAR-Opn-i axis that controls Th17 development provides insight into regulation of Th cell sublineage development and the molecular basis of type I interferon therapy for MS and other autoimmune diseases.

Can the immune system be harnessed to repair the CNS?

Experimental and clinical data have demonstrated that activating the immune system in the CNS can be destructive. However, other studies have shown that enhancing an immune response can be therapeutic, and several clinical trials have been initiated with the aim of boosting immune responses in the CNS of individuals with spinal cord injury, multiple sclerosis and Alzheimer's disease. Here, we evaluate the controversies in the field and discuss the remaining scientific challenges that are associated with enhancing immune function in the CNS to treat neurological diseases.

TNF-related apoptosis-inducing ligand (TRAIL)/Apo2L suppresses experimental autoimmune encephalomyelitis in mice

Studies have suggested that endogenous TNF-related apoptosis-inducing ligand (TRAIL)/Apo2L may suppress the induction of some autoimmune diseases in mice. Here, we show that TRAIL/Apo2L suppresses autoimmune damage in relapsing-remitting, and non-remitting models of experimental autoimmune encephalomyelitis (EAE). TRAIL/Apo2L-deficient mice and wild-type mice treated with neutralizing anti-TRAIL/Apo2L antibody displayed enhanced clinical score, increased T-cell proliferative responses to myelin oligodendrocyte glycoprotein (MOG), and increased numbers of inflammatory lesions in the spinal cord and central nervous system. TRAIL neutralization immediately before disease onset was most effective at exacerbating disease score. More importantly, therapeutic intervention with recombinant soluble TRAIL/Apo2L delayed the onset and reduced the severity of MOG-induced EAE. These data are the first to illustrate the potential therapeutic value of recombinant TRAIL/Apo2L in suppressing T-cell-mediated autoimmune diseases.

Autoimmune Processes in the Central Nervous System

In this chapter we discuss the factors that contribute to the unique immunological environment of the central nervous system and the mechanisms that may account for the development of autoimmunity within the CNS, including infectious agents as inducers of autoimmune disease. Consideration is given to a variety of human neurological diseases of autoimmune or presumed autoimmune etiology: autism, neuromyelitis optica, neuromyotonia, schizophrenia, lethargic encephalitis and stiff‐man syndrome. Also, we discuss autoimmunity as a possible mediator of CNS repair and examples of the protective effects of bacterial and helminth infections on CNS disease. Multiple sclerosis and models of multiple sclerosis are discussed with special attention given to the Theiler's virus‐induced demyelination model.

Molecular mechanisms of the anti-inflammatory functions of interferons

Interferons are pleiotropic cytokines with important proinflammatory functions required in defence against infections with bacteria, viruses and multicellular parasites. In recent years, fundamental functions of interferons in other processes such as cancer immunosurveillance, immune homeostasis and immunosuppression have been established. In addition, anti-inflammatory roles of interferons are well-documented in several inflammatory disease models in the mouse, most importantly in experimental autoimmune encephalomyelitis that resembles multiple sclerosis in humans. While the beneficial effects of interferons in such disease models are known, the molecular mechanisms remain poorly understood. Only recently a few molecular principles for the anti-inflammatory properties of interferons at the cellular level have been revealed. They include the ability of interferons to reduce the expression of the receptors for the inflammation-related cytokines IL-1 and IL-4, or to increase the expression of the potent anti-inflammatory genes tristetraprolin and Twist. However, the individual contribution of these anti-inflammatory responses to the overall beneficial effects of interferons in inflammatory diseases is still an open question. Also, the reason for the apparently limited number of tissues that are susceptible to the anti-inflammatory functions of interferons remains enigmatic. This review summarizes the present knowledge of the anti-inflammatory effects of interferons, and describes the currently known molecular mechanisms that may help explain the benefits of interferon signalling in several inflammatory diseases.

The complex etiology of multiple sclerosis

Multiple sclerosis is a demyelinating disease which is presumed to be a consequence of infiltrating lymphocytes autoreactive to myelin proteins. This is substantiated by several lines of clinical evidence and supported by correlative studies in preclinical models. The development of new therapeutics for MS has been guided by this perspective; however, the pathogenesis of MS has proven to be quite complex as observations exist which question the role of autoreactive lymphocytes in the etiology of MS. In addition the current immunomodulatory therapeutics do not prevent most patients from progressing into more serious forms of the disease. The development of truly transformational therapeutics for MS will likely require a broad assault that expands beyond the concept of MS being an autoimmune disease.

Interferons: The pathways of discovery

This article analyzes the conceptual and technological context in which, over a period of 50 years, exploration of the biological and clinical significance of type I interferon has evolved. The elaboration of techniques for production and purification of mouse and human interferons and the establishment of laboratory-size production units have been of crucial importance in this process. Animal experiments have been invaluable for elucidation of mechanisms underlying the in vivo antiviral, anti-tumour and immunomodulatory potential of interferon, but have been of limited help to define the areas of clinical applicability. Proof of principle for applications as they are established today has come from clinical trials performed quite independently of evidence from animal experiments.

Beta-interferon unbalances the peripheral T cell proinflammatory response in experimental autoimmune encephalomyelitis

Interferon beta (IFNbeta) is a widespread therapy for multiple sclerosis (MS). We have analyzed some critical features of the T cell activation process in lymph nodes after IFNbeta treatment of experimental autoimmune encephalomyelitis (EAE) in SJL mice. Prevention of clinical signs and drastic reduction of perivascular infiltrates in the central nervous system (CNS) were accompanied by alterations in nuclear DNA binding activity levels of NFkappaB and Stat6 transcription factors in lymph node cells (LNC). A decrease of active NFkappaB subunits in treated animals correlated with lower levels of the cytoplasmic phosphorylated form of IkappaBalpha. Results also showed that nuclear DNA binding activity of Stat6 was increased by IFNbeta treatment, as were the cytoplasmic levels of phosphorilated Stat6 (P-Stat6). These high levels of P-Stat6 in IFNbeta-treated animals were accompanied by an increase of IL-4 expression levels measured by real time PCR. In vitro experiments with the IL-4 producing clone D10.G4.1 indicates that the IFNbeta-mediated IL-4 induction is not an effect exclusive to MBP-reactive cells, and suggest that it could be mediated by mRNA stability enlargement. On the other hand, IFNbeta treatment of EAE produced no significant changes in peripheral IFNgamma expression and a striking decrease of IL-17. These findings suggest that the inhibition of NFkappaB activity, the increase of IL-4 expression and its signaling transduction, and the decrease of IL-17 may cooperate to some of the antiinflammatory effects of IFNbeta on EAE.

Novel insights in the immune function of the vitamin D system: synergism with interferon-beta

The 1,25(OH)(2)D(3) analog, TX527 (19-nor-14,20-bisepi-23-yne-1,25(OH)(2)D(3)), has an interesting dissociation profile between its potent immunomodulatory and its calcemic effects in vivo. The strong immunomodulatory potency of TX527 is reflected by its ability to attenuate experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS). At present most MS patients are being treated with systemic IFN-beta administration. The aim of this study was to investigate whether combining IFN-beta with TX527 could empower its EAE-protective effects. We evaluated also combinations with the standard immunosuppressant cyclosporin A (CsA). EAE was induced in SJL mice by PLP immunization, treatment was started 3 days before disease induction. The TX527+IFN-beta combination resulted in significant disease protection which was superior to the effect of both treatment separately. No disease amelioration, even aggravation, was obtained with the IFN-beta+CsA combination. By adding TX527 to the IFN-beta+CsA combination near complete protection from EAE was achieved (100% protection from paralysis, mean maximal score of 1.8+/-1.5, both p<0.05 versus controls and all individual treatments). From these data we conclude that adding TX527 to an IFN-beta and/or CsA treatment results in clear additional immunomodulatory effects in EAE prevention and is therefore a potentially interesting candidate to be considered in clinical intervention trials in MS.

Drug Insight: interferon treatment in multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of the CNS. Between 1987 and 1997, clinical trials of three preparations of recombinant interferon-beta were conducted in patients with MS, ushering in a new therapeutic era. These medications have demonstrable benefits and seem to be safe; they represent an important advance in MS treatment. All three formulations of interferon-beta had modest effects on relapses and short-term progression of disability, but the effects on MRI lesion parameters were more substantial. The benefits were greater in clinically isolated syndromes and relapsing-remitting MS than in secondary progressive MS. Although these drugs have been shown to be effective, however, their long-term impact on clinically relevant disability progression is uncertain, and there are many areas of controversy in the MS field regarding the use of these products. There is still a need for more effective treatments, which might include new agents or combination therapies.

Anti-inflammatory properties of Type I interferons

The notion that Type I interferons (interferon-alpha and -beta) possess anti-inflammatory potential is supported by data from clinical application in multiple sclerosis, by studies on cultured immune-competent cells and by investigation of experimental diseases in whole animals. These observations deserve the attention of virologists for their potential role in the pathogenesis and clinical management of virus infections.

Effects of interferon-beta-1a on neuronal survival under autoimmune inflammatory conditions

Interferon-beta-1a (IFN-beta-1a) is an approved treatment for multiple sclerosis (MS). It improves the disease course by reducing the relapse rate as well as the persistent neurological deficits. Recent MRI and post-mortem studies revealed that neuronal and axonal damage are most relevant for chronic disability in MS patients. We have characterized previously time course and mechanisms of neuronal apoptosis in a rat model of myelin oligodendrocyte glycoprotein (MOG)-induced optic neuritis. In this animal model, application of IFN-beta-1a three times per week slightly decreases the loss of retinal ganglion cells (RGCs), the neurons that form the axons within the optic nerve. In contrast to neurotrophic factors, this cytokine does not directly protect cultured RGCs from apoptosis. We conclude that IFN-beta-1a is a suitable candidate to be combined with a directly neuroprotective agent in order to further decrease axonal and neuronal degeneration in MS patients.

Gene-Based Intramuscular Interferon-β Therapy for Experimental Autoimmune Encephalomyelitis

In contrast to serial injections of recombinant interferon-beta (IFN-beta) for long-term therapy of multiple sclerosis (MS), prolonged systemic delivery of proteins derived through in vivo gene transfer may provide a more clinically relevant alternative. Here we compare the therapeutic efficacies of electroporation (EP)-mediated intramuscular IFN-beta gene transfer with repeated alternate-day injections of recombinant IFN-beta after the onset of relapsing-remitting experimental autoimmune encephalomyelitis (EAE), an animal model widely used in MS research. We show for the first time that a single EP-mediated intramuscular administration of 20 microg of an IFN-beta-expressing plasmid provides long-term expression of interferon-inducible genes and is therapeutic in ongoing established EAE. The achieved therapeutic effects of IFN-beta gene delivery were comparable to an 8-week regimen of 10,000 IU rIFN-beta injected every other day and involved a significant inhibition of disease progression and a significant reduction of EAE relapses compared to untreated or null-vector-treated mice. Our results indicate the viability of a convenient and effective gene-based alternative for long-term IFN-beta protein therapy in MS.

How to successfully apply animal studies in experimental allergic encephalomyelitis to research on multiple sclerosis

In their Point of View entitled "Experimental Allergic Encephalomyelitis: A Misleading Model of Multiple Sclerosis," Sriram and Steiner(1) wrote, "The most disappointing aspect of EAE [experimental allergic encephalomyelitis] as a potential model for MS is its almost total inability to point toward a meaningful therapy or therapeutic approach for MS." Actually, EAE has led directly to the development of three therapies approved for use in multiple sclerosis (MS): glatiramer acetate, mitoxantrone, and natalizumab. Several new approaches to MS are in clinical trials based on positive indications in preclinical work relying on EAE. New clues to the pathogenesis of MS and new potential surrogate markers for MS are shown from research involving EAE when it is critically coupled with actual findings in MS. There are pitfalls in overreliance on the EAE model, or on any animal model for any human disease. Nevertheless, over the past 73 years, the EAE model has proved itself remarkably useful for aiding research on MS.