Experimental Autoimmune Encephalomyelitis Susceptibility Research Articles

Investigating the requirement of IL-17A and IFNg in EAE disease development using HLA-DR3.IL-17A −/−.IFNg −/−transgenic mice

Abstract Multiple sclerosis (MS), an autoimmune disease of the central nervous system, is thought to be mediated by autoreactive CD4+ T cells producing IL-17A and IFNg. However, it is unclear if these cytokines are essential for disease development, progression, or both. We have shown that neither IFNg nor IL-17A, alone, are required for the development of disease in experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, but the absence of either results in different disease phenotypes. Specifically, HLA-DR3(DRB1*0301) (DR3).IFNg−/− mice develop severe atypical EAE characterized by increased levels of IL-17A, while DR3.IL-17A−/− mice develop mild, classical EAE. These data suggest that these cytokines may have compensatory roles. To further investigate the roles of these cytokines in EAE, we generated HLA-DR3.IFNg−/−.IL-17A−/− double knockout (DKO) mice and characterized their immune profiles, gut microbiomes, and disease phenotype. Our data show that DKO mice harbor distinct myeloid and CD4+ T cell profiles, myelin antigen-specific immune responses, and gut microbiota. Interestingly, DKO mice develop atypical EAE mimicking the disease phenotype of IFNg−/− mice. Thus, our data suggest that factors other than IL-17A and IFNg mediate atypical EAE susceptibility. Further characterizations of disease are ongoing in DKO mice to better define the precise roles of IL-17A and IFNg in the pathology of MS/EAE. NIAID/NIH (1R01AI137075-01) and a generous gift from Margaret Heppelmann and Michael Wacek.

STAT1 signaling protects self-reactive T cells from control by innate cells during neuroinflammation.

The transcription factor STAT1 plays a critical role in modulating the differentiation of CD4+ T cells producing IL-17 and GM-CSF, which promote the development of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). The protective role of STAT1 in MS and EAE has been largely attributed to its ability to limit pathogenic Th cells and promote Tregs. Using mice with selective deletion of STAT1 in T cells (STAT1CD4-Cre), we identified a potentially novel mechanism by which STAT1 regulates neuroinflammation independently of Foxp3+ Tregs. STAT1-deficient effector T cells became the target of NK cell–mediated killing, limiting their capacity to induce EAE. STAT1-deficient T cells promoted their own killing by producing more IL-2 that, in return, activated NK cells. Elimination of NK cells restored EAE susceptibility in STAT1CD4-Cre mice. Therefore, our study suggests that the STAT1 pathway can be manipulated to limit autoreactive T cells during autoimmunity directed against the CNS.

MicroRNA-92a promotes CNS autoimmunity by modulating the regulatory and inflammatory T cell balance.

A disequilibrium between immunosuppressive Tregs and inflammatory IL-17–producing Th17 cells is a hallmark of autoimmune diseases, including multiple sclerosis (MS). However, the molecular mechanisms underlying the Treg and Th17 imbalance in CNS autoimmunity remain largely unclear. Identifying the factors that drive this imbalance is of high clinical interest. Here, we report a major disease-promoting role for microRNA-92a (miR-92a) in CNS autoimmunity. miR-92a was elevated in experimental autoimmune encephalomyelitis (EAE), and its loss attenuated EAE. Mechanistically, miR-92a mediated EAE susceptibility in a T cell–intrinsic manner by restricting Treg induction and suppressive capacity, while supporting Th17 responses, by directly repressing the transcription factor Foxo1. Although miR-92a did not directly alter Th1 differentiation, it appeared to indirectly promote Th1 cells by inhibiting Treg responses. Correspondingly, miR-92a inhibitor therapy ameliorated EAE by concomitantly boosting Treg responses and dampening inflammatory T cell responses. Analogous to our findings in mice, miR-92a was elevated in CD4+ T cells from patients with MS, and miR-92a silencing in patients’ T cells promoted Treg development but limited Th17 differentiation. Together, our results demonstrate that miR-92a drives CNS autoimmunity by sustaining the Treg/Th17 imbalance and implicate miR-92a as a potential therapeutic target for MS.

MicroRNA control of inflammatory and regulatory T cells in CNS autoimmunity

Abstract A disequilibrium between immunosuppressive regulatory T cells (Tregs) and inflammatory interleukin (IL)-17-producing Th17 cells is a hallmark of autoimmune diseases, including multiple sclerosis (MS). However, molecular mechanisms underlying Treg and Th17 imbalance in the central nervous system (CNS) autoimmunity remain largely unclear and thus identifying factors which drive this imbalance is of high clinical interest. Recently, we found a major disease-promoting role for microRNA-92a (miR-92a) in CNS autoimmunity. MiR-92a is elevated in experimental autoimmune encephalomyelitis (EAE), and its loss attenuates EAE. Mechanistically, miR-92a mediates EAE susceptibility in a T cell-intrinsic manner by restricting Treg induction and suppressive capacity, while supporting Th17 responses by directly repressing the transcription factor, Foxo1. Correspondingly, miR-92a inhibitor therapy ameliorates EAE by modulating the balance between Tregs and Th17 cells. Analogous to mice, miR-92a is elevated in MS patient CD4+ T cells, and miR-92a silencing in patient T cells promotes Treg development while limiting Th17 differentiation. Together, our results identify a previously unknown function by which miR-92a drives CNS autoimmunity via sustaining the Treg/Th17 imbalance and implicate miR-92a as a potential therapeutic target for MS. Supported by NIH R01 R01AI127853 NMSS RG-1507-05164

HLA Class II Polymorphisms Modulate Gut Microbiota and Experimental Autoimmune Encephalomyelitis Phenotype.

Multiple sclerosis (MS) is an autoimmune disease of the CNS in which the interaction between genetic and environmental factors plays an important role in disease pathogenesis. Although environmental factors account for 70% of disease risk, the exact environmental factors associated with MS are unknown. Recently, gut microbiota has emerged as a potential missing environmental factor linked with the pathobiology of MS. Yet, how genetic factors, such as HLA class II gene(s), interact with gut microbiota and influence MS is unclear. In the current study, we investigated whether HLA class II genes that regulate experimental autoimmune encephalomyelitis (EAE) and MS susceptibility also influence gut microbiota. Previously, we have shown that HLA-DR3 transgenic mice lacking endogenous mouse class II genes (AE-KO) were susceptible to myelin proteolipid protein (91-110)-induced EAE, an animal model of MS, whereas AE-KO.HLA-DQ8 transgenic mice were resistant. Surprisingly, HLA-DR3.DQ8 double transgenic mice showed higher disease prevalence and severity compared with HLA-DR3 mice. Gut microbiota analysis showed that HLA-DR3, HLA-DQ8, and HLA-DR3.DQ8 double transgenic mice microbiota are compositionally different from AE-KO mice. Within HLA class II transgenic mice, the microbiota of HLA-DQ8 mice were more similar to HLA-DR3.DQ8 than HLA-DR3. As the presence of DQ8 on an HLA-DR3 background increases disease severity, our data suggests that HLA-DQ8-specific microbiota may contribute to disease severity in HLA-DR3.DQ8 mice. Altogether, our study provides evidence that the HLA-DR and -DQ genes linked to specific gut microbiota contribute to EAE susceptibility or resistance in a transgenic animal model of MS.

Interactions between host genetics and gut microbiota determine susceptibility to CNS autoimmunity

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. The etiology of MS is multifactorial, with disease risk determined by genetics and environmental factors. An emerging risk factor for immune-mediated diseases is an imbalance in the gut microbiome. However, the identity of gut microbes associated with disease risk, their mechanisms of action, and the interactions with host genetics remain obscure. To address these questions, we utilized the principal autoimmune model of MS, experimental autoimmune encephalomyelitis (EAE), together with a genetically diverse mouse model representing 29 unique host genotypes, interrogated by microbiome sequencing and targeted microbiome manipulation. We identified specific gut bacteria and their metabolic functions associated with EAE susceptibility, implicating short-chain fatty acid metabolism as a key element conserved across multiple host genotypes. In parallel, we used a reductionist approach focused on two of the most disparate phenotypes identified in our screen. Manipulation of the gut microbiome by transplantation and cohousing demonstrated that transfer of these microbiomes into genetically identical hosts was sufficient to modulate EAE susceptibility and systemic metabolite profiles. Parallel bioinformatic approaches identified Lactobacillus reuteri as a commensal species unexpectedly associated with exacerbation of EAE in a genetically susceptible host, which was functionally confirmed by bacterial isolation and commensal colonization studies. These results reveal complex interactions between host genetics and gut microbiota modulating susceptibility to CNS autoimmunity, providing insights into microbiome-directed strategies aimed at lowering the risk for autoimmune disease and underscoring the need to consider host genetics and baseline gut microbiome composition.

Mir106b-25 and Mir17-92 Are Crucially Involved in the Development of Experimental Neuroinflammation.

MicroRNAs (miRNAs) are single-stranded RNA that have key roles in the development of the immune system and are involved in the pathogenesis of various autoimmune diseases. We previously demonstrated that two members of the miR106b-25 cluster and the miR17-92 paralog cluster were upregulated in T regulatory cells from multiple sclerosis (MS) patients. The aim of the present work was to clarify the impact of miR106b-25 and miR17-92 clusters in MS pathogenesis. Here, we show that the mice lacking miR17-92 specifically in CD4+ T cells or both total miR106b-25 and miR17-92 in CD4+ T cells (double knockout) are protected from Experimental Autoimmune Encephalomyelitis (EAE) development while depletion of miR106b-25 only does not influence EAE susceptibility. We suggest that the absence of miR106b does not protect mice because of a mechanism of compensation of miR17-92 clusters. Moreover, the decrease of neuroinflammation was found to be associated with a significant downregulation of pro-inflammatory cytokines (GM-CSF, IFNγ, and IL-17) in the spinal cord of double knockout EAE mice and a reduction of Th17 inflammatory cells. These results elucidate the effect of miR106b-25 and miR17-92 deletion in MS pathogenesis and suggest that their targeted inhibition may have therapeutic effect on disease course.

Interactions between the host genome and the gut microbiome determine susceptibility to CNS autoimmune disease

Abstract Multiple sclerosis (MS) is a chronic autoimmune central nervous system (CNS) disease and the leading cause of non-traumatic neurological disability in young adults. The etiology of MS is multifactorial and polygenic, with 30% of risk genetic and 70% environmental. Recent studies identified an imbalance in the human gut microbiome within MS patients, including depletion of the Lactobacillus genus. Animal models support a causal role of the gut microbiome in MS, though the mechanisms remain unclear. Here, we leverage natural genetic variation in wild-derived PWD/PhJ (PWD) mice as compared to classic C57BL/6J (B6) mice, modeling human genetic diversity to identify host genome and gut microbiome interactions governing disease susceptibility. In a model of MS, experimental autoimmune encephalomyelitis (EAE), 27 consomic strains carrying PWD chromosomes on the B6 background demonstrated that PWD-derived loci exhibit bidirectional and sex-specific effects on disease severity. 16S rRNA gene sequencing of the gut microbiome in consomic and parental strains identified strain-specific profiles and metabolic functions associated with differential susceptibility to EAE. Functionally, manipulation of the gut microbiome by co-housing or transplantation, demonstrated direct host genotype-dependent effects of the microbiome on EAE susceptibility, with transfer of signature Lactobacillus species associated with changes in circulating indole metabolites and altered EAE severity. These studies reveal the presence of complex bidirectional interactions between the host genome and gut microbiome that modulate susceptibility to CNS autoimmunity, and identify specific microbiome constituents as potential therapeutic candidates.

Natural killer cells as participants in pathogenesis of rat experimental autoimmune encephalomyelitis (EAE): lessons from research on rats with distinct age and strain.

Natural killer (NK) cells, influencing dendritic cell (DC)-mediated CD4+ lymphocyte priming in draining lymph nodes (dLNs) and controlling spinal cord (SC) infiltration with encephalitogenic CD4+T lymphocytes, modulate EAE (multiple sclerosis model). This study examined their putative contribution to age-related differences in EAE development in Dark Agouti (DA) (exhibiting age-related decrease in EAE susceptibility) and Albino Oxford (AO) (becoming susceptible to EAE with aging) rats. Aging increased NK cell number in dLNs from rats of both strains. In AO rats, but not in DA ones, it also increased the numbers of IFN-γ-producing NK cells (important for DC activation) and activated/matured DCs, thereby increasing activated/matured DC/conventional Foxp3-CD4+ cell ratio and activated CD25+Foxp3-CD4+ cell number. Aging in DA rats diminished activated/matured DC/conventional Foxp3-CD4+ cell ratio and activated Foxp3-CD4+ cell number. However, MBP-stimulated CD4+ cell proliferation did not differ in dLN cell cultures from young and aged AO rats (as more favorable activated/matured DC/Foxp3-CD4+ cell ratio was abrogated by lower intrinsic CD4+ cell proliferative capacity and a greater regulatory CD25+Foxp3+CD4+ lymphocyte frequency), but was lower in those from aged compared with young DA rats. At SC level, aging shifted Foxp3-CD4+/cytotoxic CX3CR1+ NK cell ratio towards the former in AO rats, so it was less favorable in aged AO rats exhibiting prolonged neurological deficit compared with their DA counterparts. The study showed strain and age differences in number of IFN-γ-producing NK cells in EAE rat dLNs, and suggested that their pathogenetic relevance depends on frequency and/or activity of other cells involved in CD4+ T cell (auto)immune response.

Targeted Diet Modification Reduces Multiple Sclerosis-like Disease in Adult Marmoset Monkeys from an Outbred Colony.

Experimental autoimmune encephalomyelitis (EAE) in common marmosets is a translationally relevant model of the chronic neurologic disease multiple sclerosis. Following the introduction of a new dietary supplement in our purpose-bred marmoset colony, the percentage of marmosets in which clinically evident EAE could be induced by sensitization against recombinant human myelin oligodendrocyte glycoprotein in IFA decreased from 100 to 65%. The reduced EAE susceptibility after the dietary change coincided with reduced Callitrichine herpesvirus 3 expression in the colony, an EBV-related γ1-herpesvirus associated with EAE. We then investigated, in a controlled study in marmoset twins, which disease-relevant parameters were affected by the dietary change. The selected twins had been raised on the new diet for at least 12 mo prior to the study. In twin siblings reverted to the original diet 8 wk prior to EAE induction, 100% disease prevalence (eight out of eight) was restored, whereas in siblings remaining on the new diet the EAE prevalence was 75% (six out of eight). Spinal cord demyelination, a classical hallmark of the disease, was significantly lower in new-diet monkeys than in monkeys reverted to the original diet. In new-diet monkeys, the proinflammatory T cell response to recombinant human myelin oligodendrocyte glycoprotein was significantly reduced, and RNA-sequencing revealed reduced apoptosis and enhanced myelination in the brain. Systematic typing of the marmoset gut microbiota using 16S rRNA sequencing demonstrated a unique, Bifidobacteria-dominated composition, which changed after disease induction. In conclusion, targeted dietary intervention exerts positive effects on EAE-related parameters in multiple compartments of the marmoset's gut-immune-CNS axis.

Sex-Specific Gene-by-Vitamin D Interactions Regulate Susceptibility to Central Nervous System Autoimmunity.

Vitamin D3 (VitD) insufficiency is postulated to represent a major modifiable risk factor for multiple sclerosis (MS). While low VitD levels strongly correlate with higher MS risk in white populations, this is not the case for other ethnic groups, suggesting the existence of a genetic component. Moreover, VitD supplementation studies in MS so far have not shown a consistent benefit. We sought to determine whether direct manipulation of VitD levels modulates central nervous system autoimmune disease in a sex-by-genotype-dependent manner. To this end, we used a dietary model of VitD modulation, together with the autoimmune animal model of MS, experimental autoimmune encephalomyelitis (EAE). To assess the impact of genotype-by-VitD interactions on EAE susceptibility, we utilized a chromosome substitution (consomic) mouse model that incorporates the genetic diversity of wild-derived PWD/PhJ mice. High VitD was protective in EAE in female, but not male C57BL/6J (B6) mice, and had no effect in EAE-resistant PWD/PhJ (PWD) mice. EAE protection was accompanied by sex- and genotype-specific suppression of proinflammatory transcriptional programs in CD4 T effector cells, but not CD4 regulatory T cells. Decreased expression of proinflammatory genes was observed with high VitD in female CD4 T effector cells, specifically implicating a key role of MHC class II genes, interferon gamma, and Th1 cell-mediated neuroinflammation. In consomic strains, effects of VitD on EAE were also sex- and genotype dependent, whereby high VitD: (1) was protective, (2) had no effect, and (3) unexpectedly had disease-exacerbating effects. Systemic levels of 25(OH)D differed across consomic strains, with higher levels associated with EAE protection only in females. Analysis of expression of key known VitD metabolism genes between B6 and PWD mice revealed that their expression is genetically determined and sex specific and implicated Cyp27b1 and Vdr as candidate genes responsible for differential EAE responses to VitD modulation. Taken together, our results support the observation that the association between VitD status and MS susceptibility is genotype dependent and suggest that the outcome of VitD status in MS is determined by gene-by-sex interactions.

Male-specific IL-33 expression regulates sex-dimorphic EAE susceptibility

The cellular and molecular basis of sex-dimorphic autoimmune diseases, such as the CNS demyelinating disease multiple sclerosis (MS), remains unclear. Our studies in the SJL mouse model of MS, experimental autoimmune encephalomyelitis (EAE), reveal that sex-determined differences in Il33 expression by innate immune cells in response to myelin peptide immunization regulate EAE susceptibility. IL-33 is selectively induced in PLP139-151-immunized males and activates type 2 innate lymphoid cells (ILC2s), cells that promote and sustain a nonpathogenic Th2 myelin-specific response. Without this attenuating IL-33 response, females generate an encephalitogenic Th17-dominant response, which can be reversed by IL-33 treatment. Mast cells are one source of IL-33 and we provide evidence that testosterone directly induces Il33 gene expression and also exerts effects on the potential for Il33 gene expression during mast cell development. Thus, in contrast to their pathogenic role in allergy, we propose a sex-specific role for both mast cells and ILC2s as attenuators of the pathogenic Th response in CNS inflammatory disease.

Epitope-Specific Tolerance Modes Differentially Specify Susceptibility to Proteolipid Protein-Induced Experimental Autoimmune Encephalomyelitis.

Immunization with myelin components can elicit experimental autoimmune encephalomyelitis (EAE). EAE susceptibility varies between mouse strains, depending on the antigen employed. BL/6 mice are largely resistant to EAE induction with proteolipid protein (PLP), probably a reflection of antigen-specific tolerance. However, the extent and mechanism(s) of tolerance to PLP remain unclear. Here, we identified three PLP epitopes in PLP-deficient BL/6 mice. PLP-sufficient mice did not respond against two of these, whereas tolerance was “leaky” for an epitope with weak predicted MHCII binding, and only this epitope was encephalitogenic. In TCR transgenic mice, the “EAE-susceptibility-associated” epitope was “ignored” by specific CD4 T cells, whereas the “resistance-associated” epitope induced clonal deletion and Treg induction in the thymus. Central tolerance was autoimmune regulator dependent and required expression and presentation of PLP by thymic epithelial cells (TECs). TEC-specific ablation of PLP revealed that peripheral tolerance, mediated by dendritic cells through recessive tolerance mechanisms (deletion and anergy), could largely compensate for a lack of central tolerance. However, adoptive EAE was exacerbated in mice lacking PLP in TECs, pointing toward a non-redundant role of the thymus in dominant tolerance to PLP. Our findings reveal multiple layers of tolerance to a central nervous system autoantigen that vary among epitopes and thereby specify disease susceptibility. Understanding how different modalities of tolerance apply to distinct T cell epitopes of a target in autoimmunity has implications for antigen-specific strategies to therapeutically interfere with unwanted immune reactions against self.

A T cell-specific deletion of HDAC1 protects against experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a human neurodegenerative disease characterized by the invasion of autoreactive T cells from the periphery into the CNS. Application of pan-histone deacetylase inhibitors (HDACi) ameliorates experimental autoimmune encephalomyelitis (EAE), an animal model for MS, suggesting that HDACi might be a potential therapeutic strategy for MS. However, the function of individual HDAC members in the pathogenesis of EAE is not known. In this study we report that mice with a T cell-specific deletion of HDAC1 (using the Cd4-Cre deleter strain; HDAC1-cKO) were completely resistant to EAE despite the ability of HDAC1cKO CD4+ T cells to differentiate into Th17 cells. RNA sequencing revealed STAT1 as a prominent upstream regulator of differentially expressed genes in activated HDAC1-cKO CD4+ T cells and this was accompanied by a strong increase in phosphorylated STAT1 (pSTAT1). This suggests that HDAC1 controls STAT1 activity in activated CD4+ T cells. Increased pSTAT1 levels correlated with a reduced expression of the chemokine receptors Ccr4 and Ccr6, which are important for the migration of T cells into the CNS. Finally, EAE susceptibility was restored in WT:HDAC1-cKO mixed BM chimeric mice, indicating a cell-autonomous defect. Our data demonstrate a novel pathophysiological role for HDAC1 in EAE and provide evidence that selective inhibition of HDAC1 might be a promising strategy for the treatment of MS.

Modeling month-season of birth as a risk factor in mouse models of chronic disease: from multiple sclerosis to autoimmune encephalomyelitis.

Month-season of birth (M-SOB) is a risk factor in multiple chronic diseases, including multiple sclerosis (MS), where the lowest and greatest risk of developing MS coincide with the lowest and highest birth rates, respectively. To determine whether M-SOB effects in such chronic diseases as MS can be experimentally modeled, we examined the effect of M-SOB on susceptibility of C57BL/6J mice to experimental autoimmune encephalomyelitis (EAE). As in MS, mice that were born during the M-SOB with the lowest birth rate were less susceptible to EAE than mice born during the M-SOB with the highest birth rate. We also show that the M-SOB effect on EAE susceptibility is associated with differential production of multiple cytokines/chemokines by neuroantigen-specific T cells that are known to play a role in EAE pathogenesis. Taken together, these results support the existence of an M-SOB effect that may reflect seasonally dependent developmental differences in adaptive immune responses to self-antigens independent of external stimuli, including exposure to sunlight and vitamin D. Moreover, our documentation of an M-SOB effect on EAE susceptibility in mice allows for modeling and detailed analysis of mechanisms that underlie the M-SOB effect in not only MS but in numerous other diseases in which M-SOB impacts susceptibility.-Reynolds, J. D., Case, L. K., Krementsov, D. N., Raza, A., Bartiss, R., Teuscher, C. Modeling month-season of birth as a risk factor in mouse models of chronic disease: from multiple sclerosis to autoimmune encephalomyelitis.

B cell-derived transforming growth factor-β1 expression limits the induction phase of autoimmune neuroinflammation.

Studies in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), have shown that regulatory B cells modulate the course of the disease via the production of suppressive cytokines. While data indicate a role for transforming growth factor (TGF)-β1 expression in regulatory B cell functions, this mechanism has not yet been tested in autoimmune neuroinflammation. Transgenic mice deficient for TGF-β1 expression in B cells (B–TGF-β1−/−) were tested in EAE induced by recombinant mouse myelin oligodendrocyte glycoprotein (rmMOG). In this model, B–TGF-β1−/− mice showed an earlier onset of neurologic impairment compared to their littermate controls. Exacerbated EAE susceptibility in B–TGF-β1−/− mice was associated with augmented CNS T helper (Th)1/17 responses. Moreover, selective B cell TGF-β1–deficiency increased the frequencies and activation of myeloid dendritic cells, potent professional antigen-presenting cells (APCs), suggesting that B cell-derived TGF-β1 can constrain Th1/17 responses through inhibition of APC activity. Collectively our data suggest that B cells can down-regulate the function of APCs, and in turn encephalitogenic Th1/17 responses, via TGF-β1, findings that may be relevant to B cell-targeted therapies.

Cutting edge: c-Kit signaling differentially regulates type 2 innate lymphoid cell accumulation and susceptibility to central nervous system demyelination in male and female SJL mice.

Multiple sclerosis preferentially affects women, and this sexual dimorphism is recapitulated in the SJL mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). In this study, we demonstrate that signaling through c-Kit exerts distinct effects on EAE susceptibility in male and female SJL mice. Previous studies in females show that Kit mutant (W/W(v)) mice are less susceptible to EAE than are wild-type mice. However, male W/W(v) mice exhibit exacerbated disease, a phenotype independent of mast cells and corresponding to a shift from a Th2- to a Th17-dominated T cell response. We demonstrate a previously undescribed deficit in c-Kit(+) type 2 innate lymphoid cells (ILC2s) in W/W(v) mice. ILC2s are also significantly reduced in EAE-susceptible wild-type females, indicating that both c-Kit signals and undefined male-specific factors are required for ILC2 function. We propose that deficiencies in Th2-promoting ILC2s remove an attenuating influence on the encephalitogenic T cell response and therefore increases disease susceptibility.

Tolerance of activated pathogenic CD4+ T cells by transcriptional targeting of dendritic cells.

We have recently shown that targeted expression of myelin oligodendrocyte glycoprotein (MOG) to dendritic cells with self-inactivating-lentivirus vectors induces antigen-specific tolerance in naive antigen-specific CD4+ T cells and protects mice from experimental autoimmune encephalomyelitis (EAE). In the present study, we demonstrate that this approach also induces tolerance of activated antigen-specific CD4+ T cells and completely protects mice from passive EAE induction. Tolerance induction did not correlate with the depletion of the preactivated antigen-specific CD4+ T cells. However, upon isolation and in vitro re-stimulation at day 6 after adoptive transfer the MOG-specific CD4+ T cells from the non-tolerized mice produced large amounts of inflammatory cytokines, whereas those from tolerized mice did not. This unresponsiveness correlated with the upregulation of regulatory molecules associated with anergy and regulatory T cells (Tregs). The in vivo depletion of Tregs resulted in EAE susceptibility of the tolerized animals, suggesting that these cells have indeed a role in tolerance induction/maintenance.

Copy number variation in Y chromosome multicopy genes is linked to a paternal parent-of-origin effect on CNS autoimmune disease in female offspring.

BackgroundThe prevalence of some autoimmune diseases is greater in females compared with males, although disease severity is often greater in males. The reason for this sexual dimorphism is unknown, but it may reflect negative selection of Y chromosome-bearing sperm during spermatogenesis or male fetuses early in the course of conception/pregnancy. Previously, we showed that the sexual dimorphism in experimental autoimmune encephalomyelitis (EAE) is associated with copy number variation (CNV) in Y chromosome multicopy genes. Here, we test the hypothesis that CNV in Y chromosome multicopy genes influences the paternal parent-of-origin effect on EAE susceptibility in female mice.ResultsWe show that C57BL/6 J consomic strains of mice possessing an identical X chromosome and CNV in Y chromosome multicopy genes exhibit sperm head abnormalities and female-biased sex ratio. This is consistent with X-Y intragenomic conflict arising from an imbalance in CNV between homologous X:Y chromosome multicopy genes. These males also display paternal transmission of EAE to female offspring and differential loading of microRNAs within the sperm nucleus. Furthermore, in humans, families of probands with multiple sclerosis similarly exhibit a female-biased sex ratio, whereas families of probands affected with non-sexually dimorphic autoimmune diseases exhibit unbiased sex ratios.ConclusionsThese findings provide evidence for a mechanism at the level of the male gamete that contributes to the sexual dimorphism in EAE and paternal parent-of-origin effects in female mice, raising the possibility that a similar mechanism may contribute to the sexual dimorphism in multiple sclerosis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-015-0591-7) contains supplementary material, which is available to authorized users.

Myelin oligodendrocyte glycoprotein (MOG35-55) induced experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice.

Multiple sclerosis is a chronic neuroinflammatory demyelinating disorder of the central nervous system with a strong neurodegenerative component. While the exact etiology of the disease is yet unclear, autoreactive T lymphocytes are thought to play a central role in its pathophysiology. MS therapy is only partially effective so far and research efforts continue to expand our knowledge on the pathophysiology of the disease and to develop novel treatment strategies. Experimental autoimmune encephalomyelitis (EAE) is the most common animal model for MS sharing many clinical and pathophysiological features. There is a broad diversity of EAE models which reflect different clinical, immunological and histological aspects of human MS. Actively-induced EAE in mice is the easiest inducible model with robust and replicable results. It is especially suited for investigating the effects of drugs or of particular genes by using transgenic mice challenged by autoimmune neuroinflammation. Therefore, mice are immunized with CNS homogenates or peptides of myelin proteins. Due to the low immunogenic potential of these peptides, strong adjuvants are used. EAE susceptibility and phenotype depends on the chosen antigen and rodent strain. C57BL/6 mice are the commonly used strain for transgenic mouse construction and respond among others to myelin oligodendrocyte glycoprotein (MOG). The immunogenic epitope MOG35-55 is suspended in complete Freund's adjuvant (CFA) prior to immunization and pertussis toxin is applied on the day of immunization and two days later. Mice develop a "classic" self-limited monophasic EAE with ascending flaccid paralysis within 9-14 days after immunization. Mice are evaluated daily using a clinical scoring system for 25-50 days. Special considerations for care taking of animals with EAE as well as potential applications and limitations of this model are discussed.