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Neuronal oxidative stress has been implicated in aging and neurodegenerative disease. Here we investigated the impact of elevated oxidative stress induced in mouse spinal cord by deletion of Mn-Superoxide dismutase (MnSOD) using a neuron specific Cre recombinase in Sod2 floxed mice (i-mn-Sod2 KO). Sod2 deletion in spinal cord neurons was associated with mitochondrial alterations and peroxide generation. Phenotypically, i-mn-Sod2 KO mice experienced hindlimb paralysis and clasping behavior associated with extensive demyelination and reduced nerve conduction velocity, axonal degeneration, enhanced blood brain barrier permeability, elevated inflammatory cytokines, microglia activation, infiltration of neutrophils and necroptosis in spinal cord. In contrast, spinal cord motor neuron number, innervation of neuromuscular junctions, muscle mass, and contractile function were not altered. Overall, our findings show that loss of MnSOD in spinal cord promotes a phenotype of demyelination, inflammation and progressive paralysis that mimics phenotypes associated with progressive multiple sclerosis.

ObjectiveIdentify autoantibodies in anti-Ro/SS-A negative primary Sjögren’s syndrome (SS).MethodsThis is a proof-of-concept, case-control study of SS, healthy (HC) and other disease (OD) controls. A discovery dataset of plasma samples (n=30 SS, n=15 HC) was tested on human proteome arrays containing 19 500 proteins. A validation dataset of plasma and stimulated parotid saliva from additional SS cases (n=46 anti-Ro+, n=50 anti-Ro–), HC (n=42) and OD (n=54) was tested on custom arrays containing 74 proteins. For each protein, the mean+3 SD of the HC value defined the positivity threshold. Differences from HC were determined by Fisher’s exact test and random forest machine learning using 2/3 of the validation dataset for training and 1/3 for testing. Applicability of the results was explored in an independent rheumatology practice cohort (n=38 Ro+, n=36 Ro–, n=10 HC). Relationships among antigens were explored using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) interactome analysis.ResultsRo+SS parotid saliva contained autoantibodies binding to Ro60, Ro52, La/SS-B and muscarinic receptor 5. SS plasma contained 12 novel autoantibody specificities, 11 of which were detected in both the discovery and validation datasets. Binding to ≥1 of the novel antigens identified 54% of Ro–SS and 37% of Ro+SS cases, with 100% specificity in both groups. Machine learning identified 30 novel specificities showing receiver operating characteristic area under the curve of 0.79 (95% CI 0.64 to 0.93) for identifying Ro–SS. Sera from Ro–cases of an independent cohort bound 17 of the non-canonical antigens. Antigenic targets in both Ro+and Ro–SS were part of leukaemia cell, ubiquitin conjugation and antiviral defence pathways.ConclusionWe identified antigenic targets of the autoantibody response in SS that may be useful for identifying up to half of Ro seronegative SS cases.

Von Hippel–Lindau (VHL) is an E3 ubiquitin ligase that targets proteins, including HIF-1α, for proteasomal degradation. VHL and HIF regulate the balance between glycolysis and oxidative phosphorylation, which is critical in highly dynamic T cells. HIF-1α positively regulates Th17 differentiation, a complex process in which quiescent naive CD4 T cells undergo transcriptional changes to effector cells, which are commonly dysregulated in autoimmune diseases. The role of VHL in Th17 cells is not known. In this study, we hypothesized VHL negatively regulates Th17 differentiation and deletion of VHL in CD4 T cells would elevate HIF-1α and increase Th17 differentiation. Unexpectedly, we found that VHL promotes Th17 differentiation. Mice deficient in VHL in their T cells were resistant to an autoimmune disease, experimental autoimmune encephalomyelitis, often mediated by Th17 cells. In vitro Th17 differentiation was impaired in VHL-deficient T cells. In the absence of VHL, Th17 cells had decreased activation of STAT3 and SMAD2, suggesting that VHL indirectly or directly regulates these critical signaling molecules. Gene expression analysis revealed that in Th17 cells, VHL regulates many cellular pathways, including genes encoding proteins involved indirectly or directly in the glycolysis pathway. Compared with wild-type, VHL-deficient Th17 cells had elevated glycolysis and glycolytic capacity. Our finding has implications on the design of therapeutics targeting the distinct metabolic needs of T cells to combat chronic inflammatory diseases.

Type I interferon (IFN-I) and T helper 17 (TH17) drive pathology in neuromyelitis optica spectrum disorder (NMOSD) and in TH17-induced experimental autoimmune encephalomyelitis (TH17-EAE). This is paradoxical because the prevalent theory is that IFN-I inhibits TH17 function. Here we report that a cascade involving IFN-I, IL-6 and B cells promotes TH17-mediated neuro-autoimmunity. In NMOSD, elevated IFN-I signatures, IL-6 and IL-17 are associated with severe disability. Furthermore, IL-6 and IL-17 levels are lower in patients on anti-CD20 therapy. In mice, IFN-I elevates IL-6 and exacerbates TH17-EAE. Strikingly, IL-6 blockade attenuates disease only in mice treated with IFN-I. By contrast, B-cell-deficiency attenuates TH17-EAE in the presence or absence of IFN-I treatment. Finally, IFN-I stimulates B cells to produce IL-6 to drive pathogenic TH17 differentiation in vitro. Our data thus provide an explanation for the paradox surrounding IFN-I and TH17 in neuro-autoimmunity, and may have utility in predicting therapeutic response in NMOSD., Type I IFN has apposing effects in neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). Here the authors perform molecular profiling of NMOSD patients and mouse mechanistic experiments of neuro-inflammation to show that IFN-I stimulates pathogenic Th17 via IL-6 production by B cells.

Rationale: B cells have emerged as key regulators in protective cancer immunity. However, the activation pathways induced in B cells during effective immunotherapy are not well understood. Methods: We used a novel localized ablative immunotherapy (LAIT), combining photothermal therapy (PTT) with intra-tumor delivery of the immunostimulant N-dihydrogalactochitosan (GC), to treat mice bearing mouse mammary tumor virus-polyoma middle tumor-antigen (MMTV-PyMT). We used single-cell RNA sequencing to compare the transcriptional changes induced by PTT, GC and PTT+GC in B cells within the tumor microenvironment (TME). Results: LAIT significantly increased survival in the tumor-bearing mice, compared to the treatment by PTT and GC alone. We found that PTT, GC and PTT+GC increased the proportion of tumor-infiltrating B cells and induced gene expression signatures associated with B cell activation. Both GC and PTT+GC elevated gene expression associated with antigen presentation, whereas GC elevated transcripts that regulate B cell activation and GTPase function and PTT+GC induced interferon response genes. Trajectory analysis, where B cells were organized according to pseudotime progression, revealed that both GC and PTT+GC induced the differentiation of B cells from a resting state towards an effector phenotype. The analyses confirmed upregulated interferon signatures in the differentiated tumor-infiltrating B cells following treatment by PTT+GC but not by GC. We also observed that breast cancer patients had significantly longer survival time if they had elevated expression of genes in B cells that were induced by PTT+GC therapy in the mouse tumors. Conclusion: Our findings show that the combination of local ablation and local application of immunostimulant initiates the activation of interferon signatures and antigen-presentation in B cells which is associated with positive clinical outcomes for breast cancer. These findings broaden our understanding of LAIT's regulatory roles in remodeling TME and shed light on the potentials of B cell activation in clinical applications.

Interferon (IFN)-β is a popular therapy for multiple sclerosis (MS). However, 25–40% of patients are nonresponsive to this therapy, and it worsens neuromyelitis optica (NMO), another neuroinflammatory disease. We previously identified, in both NMO patients and in mice, that IFN-β treatment had inflammatory effects in T Helper (TH) 17-induced disease through the production of the inflammatory cytokine IL-6. However, other studies have shown that IFN-β inhibits the differentiation and function of TH17 cells. In this manuscript, we identified that IFN-β had differential effects on discrete stages of TH17 development. During early TH17 development, IFN-β inhibits IL-17 production. Conversely, during late TH17 differentiation, IFN-β synergizes with IL-23 to promote a pathogenic T cell that has both TH1 and TH17 characteristics and expresses elevated levels of the potent inflammatory cytokines IL-6 and GM-CSF and the transcription factor BLIMP. Together, these findings help resolve a paradox surrounding IFN-β and TH17-induced disease and illuminate the pathways responsible for the pathophysiology of NMO and MS patients who are IFN-β nonresponders.

The CD1d-binding glycolipid α-galactosylceramide (α-GC) is a potent adjuvant that activates NKT cells and in turn enhances T-dependent humoral immunity. Very little is known about how NKT cells and the NKT follicular helper (NKTfh) subset influence the immune response to T-independent polysaccharides. In this study, we used a Cre-Lox approach to generate mice devoid of the Bcl6 master transcription factor in CD4 lineage cells and thus devoid of NKTfh cells but not total NKT cells. It was observed that α-GC–driven IgG1 class switch against a polysaccharide Ag was dependent on the NKTfh subset. However, α-GC was unable to stimulate a polysaccharide-specific Ab recall response. It was observed that NKT-derived IL-21 was able to exert limited influence on the IgG1 response and was therefore likely to work in concert with other factors. This work shows that α-GC–driven NKTfh cells can direct polysaccharide-specific B cell responses by promoting IgG1 class switch but do not provide signals needed for generation of polysaccharide-specific B cell memory.

BACKGROUND: For relapsing-remitting multiple sclerosis (RRMS), there is a need for biomarker development beyond clinical manifestations and MRI. Soluble neurofilament light chain (sNfL) has emerged as a biomarker for inflammatory activity in RRMS. However, there are limitations to the accuracy of sNfL in identifying relapses. Here, we sought to identify a panel of biomarkers that would increase the precision of distinguishing patients in relapse compared to sNfL alone. METHODS: We used a multiplex approach to measure levels of 724 blood proteins in two distinct RRMS cohorts. Multiple t-tests with covariate correction determined biomarkers that were differentially regulated in relapse and remission. Logistic regression models determined the accuracy of biomarkers to distinguish relapses from remission. RESULTS: The discovery cohort identified 37 proteins differentially abundant in active RRMS relapse compared to remission. The verification cohort confirmed four proteins, including sNfL, were altered in active RRMS relapse compared to remission. Logistic regression showed that the 4-protein panel identified active relapse with higher accuracy (AUC = 0.87) than sNfL alone (AUC = 0.69). CONCLUSION: Our studies confirmed that sNfL is elevated during relapses in RRMS patients. Furthermore, we identified three other blood proteins, uPA, hK8 and DSG3 that were altered during relapse. Together, these four biomarkers could be used to monitor disease activity in RRMS patients.

Pertussis toxin (PTX) is a required co-adjuvant for experimental autoimmune encephalomyelitis (EAE) induced by immunization with myelin antigen. However, PTX’s effects on EAE induced by the transfer of myelin-specific T helper cells is not known. Therefore, we investigated how PTX affects the Th17 transfer EAE model (Th17-EAE). We found that PTX significantly reduced Th17-EAE by inhibiting chemokine-receptor-dependent trafficking of Th17 cells. Strikingly, PTX also promoted the accumulation of B cells in the CNS, suggesting that PTX alters the disease toward a B-cell-dependent pathology. To determine the role of B cells, we compared the effects of PTX on Th17-EAE in wild-type (WT) and B-cell-deficient (µMT) mice. Without PTX treatment, disease severity was equivalent between WT and µMT mice. In contrast, with PTX treatment, the µMT mice had significantly less disease and a reduction in pathogenic Th17 cells in the CNS compared to the WT mice. In conclusion, this study shows that PTX inhibits the migration of pathogenic Th17 cells, while promoting the accumulation of pathogenic B cells in the CNS during Th17-EAE. These data provide useful methodological information for adoptive-transfer Th17-EAE and, furthermore, describe another important experimental system to study the pathogenic mechanisms of B cells in multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination of neurons and inflammation in the central nervous system. MS afflicts approximately 2.5 million people worldwide. Understanding how viral infection affects MS disease is of great importance because the immune-suppressive effects of some MS therapies can make patients more vulnerable to viral infections. The goal of our project is to elucidate the effect of respiratory viral infection in a B cell-driven experimental autoimmune encephalomyelitis (EAE), which models the immune pathology of MS. Here, we describe a comorbid animal model in which mice were immunized with hMOG1–125 to induce EAE and subsequently infected prior to disease onset with a sublethal dose of the H1N1 Influenza A mouse-adapted A/Puerto Rico/8/1934 virus (IAV). Our data show that comorbid mice have a less severe EAE paralysis phenotype than mice with EAE alone. Flow cytometry analyses show that the lungs of comorbid mice had increased neutrophil numbers and a reciprocal reduction in MHCII+ CD86+ inflammatory monocytes. Comorbid mice also had fewer germinal center B cells in the lungs and reduced levels of IAV-specific IgM and IgG antibodies compared to IAV-infected controls. Secondary IAV challenge of comorbid mice revealed deficits in immunological B cell memory. Overall, our data show that EAE disrupts the antiviral immune response, including by decreasing the IAV-specific B cell response. Paradoxically, viral infection decreased EAE severity, indicating that the antiviral immune response attenuates B cell-dependent neuroinflammation. Future studies will determine mechanisms by which inflammation induced by viral infection modulates neuroinflammatory diseases. Supported by grants from NIH (R01AI137047 and R01EY027346) A grant awarded to Dr. Kovats and Dr. Axtell from the Presbyterian Health Foundation

Multiple sclerosis (MS) is immune mediated demyelinating disease of the central nervous system (CNS) leading to neuronal damage. The disease is heterogeneous with respect to onset and clinical course, being more prevalent in women then in men with a ratio of 3:1. Further sex differences have been observed with males having a more severe and debilitating disease course compared to females. The complex interplay of immune cells, sex hormones or genetic differences could be contributing to these clinical phenomena, which remains to be elucidated. In experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, several reports have demonstrated no sex differences in disease onset or severity in C57BL/6 mice. Herein we report that deficiency in B Cell Maturation Antigen (BCMA) in C57BL/6 mice reveals a sex difference in EAE. BCMA plays a prominent role in B cell function, however the role BCMA plays in MS and EAE is unknown. Our initial goal of this project was to determine the impact BCMA deficiency has on EAE. In doing so we confirmed that EAE disease was not different in males and females from BCMA+/+ mice. Strikingly in the BCMA−/− mice, there was a significant increase in EAE disease severity in males compared to females. The increased EAE in the BCMA−/− male mice was associated with increased demyelination and infiltration of inflammatory T cells and macrophages into CNS. Also, we observed decreased splenic transitional B cells in male BCMA−/− mice compared to females. Castration of mice significantly reduces EAE in BCMA−/− mice as compared to sham controls. Altogether, our data demonstrate that male hormones exacerbates EAE in BCMA−/− mice by augmenting inflammatory responses compared to females leading to increased neuro-inflammation. Supported by NIH (R01AI137047 and R01EY027346)

B cell depletion therapy with anti-CD20 antibodies ameliorates autoimmune diseases such as multiple sclerosis, rheumatoid arthritis as well as haematological malignancies. Anti-CD20 antibodies deplete pre-B cells, mature B cells and malignant B cells but do not reduce plasma cells. Recently, studies have associated anti-CD20 therapy with severe manifestation of SARS-CoV2 infection. However, the mechanism of this adverse effect of anti-CD20 therapy remains unclear. This study was undertaken to investigate the effect of anti-CD20 therapy on respiratory viral infection. C57BL/6 mice were treated with anti-CD20 antibody to induce B cell depletion and then were infected intratracheally with H1N1 Influenza A mouse-adapted A/Puerto Rico/8/1934 virus (IAV). Our results show that B cell depletion therapy worsens lung infection with more severe and prolonged weight loss. Higher viral titers were found in the lungs of anti-CD20 treated mice, indicating impairment in virus clearance. Flow cytometry analysis showed no difference between groups in CD4+ and CD8+ PR8 antigen specific T cells on day 9 post-infection. However, higher numbers of inflammatory, SiglecF+ neutrophils were found in B cell depleted mice. In summary, our data show that anti-CD20 therapy exacerbates the viral pathology in respiratory lung infections. We further have identified that B cell depletion therapy affects viral clearance and inflammatory neutrophils but has no effect on T cell numbers in the lung at the peak of infection. Our future studies will identify the mechanisms driving the severe pathology in influenza infection with B cell depletion. Supported by grants from NIH (R01AI137047 and R01EY027346) A grant awarded to Dr. Kovatz and Dr Axtell from the Presbyterian Health Foundation

Recent studies identified that interferon beta (IFN-β) treatment skews B-cells towards a regulatory phenotype in multiple sclerosis. To assess B cell involvement during IFN-β therapy, we compared IFN-β treatment in a B cell-independent model and a B cell-dependent model of experimental autoimmune encephalomyelitis (EAE). We show that in B cell-independent EAE, IFN-β ameliorates neuroinflammation. Conversely, in B cell-dependent EAE, IFN-β has no effect on disease. Effective IFN-β therapy in B cell-independent EAE was associated with reduced inflammatory T cells in the CNS and skewed splenic B cells towards an immature population and away from a germinal center population. These immune cell populations were unchanged in B cell-dependent EAE. Finally, we found that IFN-β increased marginal zone B cells in both EAE models. These findings indicate that B cell function impacts IFN-β efficacy during neuroinflammation.

Pertussis toxin (PTX) is required as a co-adjuvant to induce disease in active Experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. The objective of this study was to investigate the role of PTX during adoptive transfer TH17-EAE and observe alterations in the disease phenotype. TH17-EAE was induced by transferring myelin-specific TH17 cells, harvested from MOG35-55 immunized wild type (WT) donor mice, into WT or B cell deficient (μMT) recipient mice. The recipient mice also received PTX or PBS on days 0 and 2 and monitored for paralysis. In WT mice, PTX significantly reduced disease severity and delayed onset of paralysis. PTX reduced accumulation of pathogenic T helper cells and myeloid cells in the CNS, which we found to be associated with PTX inhibition of chemokine receptor dependent trafficking. Strikingly, our data shows that PTX promotes the accumulation of B cells in the CNS and elevates the capacity of B cells to present antigen to T cells in the periphery, suggesting an altered disease toward a B cell-dependent pathology. We found that without PTX treatment, the severity of disease was equivalent between WT and μMT mice. In contrast, with PTX treatment, the μMT mice had significantly less disease compared to the WT mice. In conclusion, our data suggests that during TH17-EAE, PTX restricts the trafficking of pathogenic T helper cells and myeloid cells into the CNS and thereby delays the disease onset. However, not only PTX does not alter trafficking of B cells into the CNS it also stimulates a more inflammatory B cell phenotype. This study provides novel insights to interactions between TH17 and B cells in mice and has defined a new model to study the pathologic functions of B cells during multiple sclerosis.

Multiple sclerosis is a demyelinating disease caused by immune cell infiltration into the Central Nervous System (CNS). Relapsing Remitting Multiple Sclerosis (RRMS) is characterized by episodes of worsening disability (relapses) followed by complete or partial recovery (remissions). Currently, MRI scans are used to conclusively identify relapses, but there is a need for an inexpensive, non-invasive test for monitoring relapses and remission status in MS patients. Serum neurofilament light (NFL) has emerged as a biomarker for relapse in MS. However, a test using NFL alone has poor sensitivity and specificity to identify an MS relapse. Our goal was to identify a panel of biomarkers that could improve the accuracy of distinguishing relapse and remission in MS patients. We used a multiplexed, sensitive assay to measure levels of blood proteins in two cohorts of RRMS patients – a cross-sectional cohort and a longitudinal cohort. In the cross-sectional patient cohort, we found five serum proteins were elevated in relapse, including NFL. Furthermore, we identified 94 serum proteins that were significantly reduced in relapse compared to remission, including IFN responsive chemokines CXCL9 and CXCL11. For the longitudinal cohort, pairwise comparisons found that five plasma proteins were elevated in relapse compared to remission, including NFL. Nine plasma proteins were significantly reduced in relapse compared to remission, including the IFN responsive chemokines CXCL9 and CXCL10. In conclusion, our studies provide evidence that a panel including NFL and IFN responsive chemokines in the blood may serve as biomarkers to distinguish relapse and remission in RRMS patients.

Multiple sclerosis (MS) and glioblastoma (GBM) are two distinct diseases that affect the central nervous system (CNS). However, perturbation in CNS vasculature are hallmarks of both diseases. ELTD1 (epidermal growth factor, latrophilin, and 7 transmembrane domain containing protein 1 on chromosome 1) is associated with vascular development, and has been linked with tumor angiogenesis. In glioblastomas, we detected over-expression of ELTD1, and found that an antibody targeting ELTD1 could increase animal survival and decrease tumor volumes in a xenograft GBM model. RNA-seq analysis of the preclinical data in the model for GBM identified that some of the molecular pathways affected by the anti-ELTD1 antibody therapy are also found to be associated with MS. In this study, we used molecular-targeted (mt) MR imaging and immunohistochemistry to assess ELTD1 levels in experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Specifically, we found that ELTD1 is readily detected in the brains of mice with EAE and is predominantly found in the corpus callosum. In addition, we found that the blood-brain barrier (BBB) was compromised in the brains of EAE mice using contrast-enhanced MRI (CE-MRI), as well as altered relative cerebral blood flow (rCBF) in the brains and cervical spinal cords of these mice using perfusion imaging, compared to controls. These findings indicate that ELTD1 may be a promising biomarker for CNS-inflammation in MS.

ObjectiveB cells have emerged as a therapeutic target for MS. Anti-CD20 antibodies, which deplete B cells, are effective therapies for MS. However, atacicept (TACI-Fc), which blocks BAFF and APRIL and reduces B cells, unexpectedly exacerbates MS. We tested the hypothesis that B cell maturation antigen (BCMA), a receptor for BAFF and APRIL, plays a role in the paradoxical effects of anti-CD20 antibody and TACI-Fc using experimental autoimmune encephalomyelitis (EAE).MethodsEAE was induced in wild-type (BCMA+/+) and BCMA-deficient (BCMA−/−) mice with an immunization of rodent myelin oligodendrocyte glycoprotein (MOG)35–55 peptide. Treatment with anti-CD20 antibody, TACI-Fc, and isotype controls was administered by intraperitoneal injections. CNS infiltration was evaluated by histology; immune cell phenotypes were evaluated by flow cytometry; MOG-specific antibodies were determined by ELISA. Mixed bone marrow chimeras and cell culture assays were used to identify the specific subsets of immune cells affected by BCMA deficiency.ResultsFirst, we found that BCMA−/− mice had more severe EAE compared with BCMA+/+ mice and the increased disease was associated with elevated anti-MOG B-cell responses. Second, we found that anti-CD20 therapy attenuated EAE in BCMA−/− mice but not in BCMA+/+ mice. Third, TACI-Fc attenuated EAE in BCMA+/+ mice but not in BCMA−/− mice. Mixed bone marrow chimeric and cell culture experiments demonstrated that BCMA deficiency elevates inflammatory B-cell responses but inhibits inflammatory responses in macrophages.ConclusionsBCMA has multifaceted roles during inflammation that affects therapeutic efficacies of anti-CD20 and TACI-Fc in EAE. Our results from BCMA-deficient mice provide insights into the failure of atacicept in MS.

Multiple sclerosis (MS) is immune mediated demyelinating disease of the central nervous system (CNS) leading to neuronal damage. The disease is heterogeneous with respect to onset and clinical course, being more prevalent in women then in men with a ratio of 3:1. Further sex differences have been observed with males having a more severe and debilitating disease course compared to females. The complex interplay of immune cells, sex hormones or genetic differences could be contributing to these clinical phenomena, which remains to be elucidated. In experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, several reports have demonstrated no sex differences in disease onset or severity in C57BL/6 mice. Herein we report that deficiency in B Cell Maturation Antigen (BCMA) in C57BL/6 mice reveals a sex difference in EAE. BCMA plays a prominent role in B cell function, however the role BCMA plays in MS and EAE is unknown. Our initial goal of this project was to determine the impact BCMA deficiency has on EAE. In doing so we confirmed that EAE disease was not different in males and females from BCMA+/+mice. Strikingly in the BCMA−/− mice, there was a significant increase in EAE disease severity in males compared to females. The increased EAE in the BCMA−/− male mice was associated with increased demyelination and infiltration of inflammatory T cells and macrophages into CNS. Also, we observed decreased splenic transitional B cells in male BCMA−/− mice compared to females. Castration of mice significantly reduces EAE in BCMA−/− mice as compared to sham controls. Altogether, our data demonstrate that male hormones exacerbates EAE in BCMA−/− mice by augmenting inflammatory responses compared to females leading to increased neuro-inflammation.

B cells have emerged as a therapeutic target for multiple sclerosis (MS). Depleting B cells with anti-CD20 antibodies are effective in treating MS. Yet, TACI-Ig treatment, which blocks BAFF and APRIL (two cytokines important for B cell development and function), paradoxically increased disease activity in MS patients. The stark differences in clinical outcomes with these therapies demonstrate that B cells have both inflammatory and regulatory effects in MS. B cell Maturation Antigen (BCMA), a receptor that binds BAFF and APRIL, plays a prominent role in B cell function. The role BCMA plays in MS remains enigmatic and therefore we explored the impact BCMA deficiency has on the development and progression of the experimental autoimmune encephalomyelitis (EAE), a rodent model of MS. Here, we identified that the expression of BCMA is dysregulated in B cells from MS patients and is important in inhibiting inflammatory B cell responses in EAE. We discovered that BCMA expression is decreased on transitional B cells in MS. In mice we found that EAE induced with MOG35–55 was severe in BCMA−/− mice compared to BCMA+/+. The increased disease was associated with increased CNS inflammation, significantly reduced transitional B cells and a skewing of B-cells toward a mature/inflammatory phenotype. Bone marrow chimeric and in vitro experiments demonstrated that BCMA directly inhibits memory B cell expansion and anti-inflammatory cytokine production by B cells. Strikingly, BCMA impacts the efficacy of B cell depleting therapies, as anti-CD20 antibody treatment attenuated EAE in BCMA-deficient mice but not BCMA-sufficient mice. These data provide novel insights into B-cell dysregulation in MS.

Multiple sclerosis (MS) is an autoimmune demyelinating disease with progressive neurodegeneration and complex etiology likely involving genetic and environmental factors. MS has been associated with Epstein Barr virus (EBV) infection, with patients often showing enhanced responses to EBV antigens. To determine whether abnormal EBV nuclear antigen-1 (EBNA-1) humoral immunity can serve as an initiator of autoimmune responses in MS, we investigated the fine specificities of the humoral immune response against EBNA-1 in MS patients using solid phase epitope mapping. Antibodies from MS patients recognized an EBNA-1 epitope spanning amino acids 411–426, previously unknown to be recognized specifically by untreated MS patients. Antibodies against this epitope cross-reacted to myelin basic protein (MBP). Furthermore, animals immunized with this EBNA-1 polypeptide mounted a response against MBP and developed signs of experimental autoimmune encephalitis (EAE). These data support a link between MS and EBV through antibodies that cross-react between EBV proteins and the MBP autoantigen.

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.

Understanding the consequences of tuning TCR signaling on selection, peripheral T cell function, and tolerance in the context of native TCR repertoires may provide insight into the physiological control of tolerance. In this study, we show that genetic ablation of a natural tuner of TCR signaling, mir-181a-1/b-1, in double-positive thymocytes dampened TCR and Erk signaling and increased the threshold of positive selection. Whereas mir-181a-1/b-1 deletion in mice resulted in an increase in the intrinsic reactivity of naive T cells to self-antigens, it did not cause spontaneous autoimmunity. Loss of mir-181a-1/b-1 dampened the induction of experimental autoimmune encephalomyelitis and reduced basal TCR signaling in peripheral T cells and their migration from lymph nodes to pathogenic sites. Taken together, these results demonstrate that tolerance can be modulated by microRNA gene products through the control of opposing activities in T cell selection and peripheral T cell function.

IFN-β remains the most widely prescribed treatment for relapsing remitting multiple sclerosis. Despite widespread use of IFN-β, the therapeutic mechanism is still partially understood. Particularly, the clinical relevance of increased B cell activity during IFN-β treatment is unclear. In this article, we show that IFN-β pushes some B cells into a transitional, regulatory population that is a critical mechanism for therapy. IFN-β treatment increases the absolute number of regulatory CD19+CD24++CD38++ transitional B cells in peripheral blood relative to treatment-naive and Copaxone-treated patients. In addition, we found that transitional B cells from both healthy controls and IFN-β–treated MS patients are potent producers of IL-10, and that the capability of IFN-β to induce IL-10 is amplified when B cells are stimulated. Similar changes are seen in mice with experimental autoimmune encephalomyelitis. IFN-β treatment increases transitional and regulatory B cell populations, as well as IL-10 secretion in the spleen. Furthermore, we found that IFN-β increases autoantibody production, implicating humoral immune activation in B cell regulatory responses. Finally, we demonstrate that IFN-β therapy requires immune-regulatory B cells by showing that B cell–deficient mice do not benefit clinically or histopathologically from IFN-β treatment. These results have significant implications for the diagnosis and treatment of relapsing remitting multiple sclerosis.

The objective of this study was to evaluate monthly intramuscular adrenocorticotropic hormone (ACTH) gelThis was a prospective, open-label, examiner-blinded, 15-month pilot study evaluating patients with Expanded Disability Status Scale (EDSS) score 3.0-6.5 and at least one clinical relapse or new T2 or gadolinium-enhanced lesion in the previous year. Twenty-three patients were randomized to ACTH (Relapse rates differed significantly [ACTH 0.08, 95% confidence interval (CI) 0.01-0.54This study provided class II evidence that ACTH produced better examiner-assessed cumulative rates of relapses per patient than IVMP in the adjunctive treatment of breakthrough disease in multiple sclerosis.

Background: The objective of this study was to evaluate monthly intramuscular adrenocorticotropic hormone (ACTH) gel versus intravenous methylprednisolone (IVMP) add-on therapy to interferon β for breakthrough disease in patients with relapsing forms of multiple sclerosis. Methods: This was a prospective, open-label, examiner-blinded, 15-month pilot study evaluating patients with Expanded Disability Status Scale (EDSS) score 3.0–6.5 and at least one clinical relapse or new T2 or gadolinium-enhanced lesion in the previous year. Twenty-three patients were randomized to ACTH ( n = 12) or IVMP ( n = 11) and completed the study. The primary outcome measure was the cumulative number of relapses. Secondary outcomes included EDSS, Mental Health Inventory (MHI), plasma cytokines, MS Functional Composite (MSFC), Quality-of-Life (MS-QOL) score, bone mineral density (BMD), and new or worsened psychiatric symptoms per month. Brain magnetic resonance imaging was analyzed post hoc. This was a preliminary and small-scale study. Results: Relapse rates differed significantly [ACTH 0.08, 95% confidence interval (CI) 0.01–0.54 versus IVMP 0.80, 95% CI 0.36–1.75; rate ratio, IVMP versus ACTH: 9.56, 95% CI 1.23–74.6; p = 0.03]. ACTH improved ( p = 0.03) MHI (slope 0.95 ± 0.38 points/month; p = 0.02 versus slope −0.38 ± 0.43 points/month; p = 0.39). On-study decreases (all p < 0.05) in eight cytokine levels occurred only in the ACTH group. However, on-study EDSS, MSFC, MS-QOL, BMD, and MRI lesion changes were not significant between groups. Psychiatric symptoms per patient were greater with IVMP than ACTH (0.55, 95% CI 0.12–2.6 versus 0; p < 0.0001). Other common adverse events were insomnia and urinary tract infections (IVMP, seven events each) and fatigue or flu symptoms (ACTH, five events each). Conclusions: This study provided class II evidence that ACTH produced better examiner-assessed cumulative rates of relapses per patient than IVMP in the adjunctive treatment of breakthrough disease in multiple sclerosis.

The balance between controlling infection and limiting inflammation is particularly precarious in the brain because of its unique vulnerability to the toxic effects of inflammation. Astrocytes have been implicated as key regulators of neuroinflammation in CNS infections, including infection with Toxoplasma gondii, a protozoan parasite that naturally establishes a chronic CNS infection in mice and humans. In CNS toxoplasmosis, astrocytes are critical to controlling parasite growth. They secrete proinflammatory cytokines and physically encircle parasites. However, the molecular mechanisms used by astrocytes to limit neuroinflammation during toxoplasmic encephalitis have not yet been identified. TGF-β signaling in astrocytes is of particular interest because TGF-β is universally upregulated during CNS infection and serves master regulatory and primarily anti-inflammatory functions. We report in this study that TGF-β signaling is activated in astrocytes during toxoplasmic encephalitis and that inhibition of astrocytic TGF-β signaling increases immune cell infiltration, uncouples proinflammatory cytokine and chemokine production from CNS parasite burden, and increases neuronal injury. Remarkably, we show that the effects of inhibiting astrocytic TGF-β signaling are independent of parasite burden and the ability of GFAP+ astrocytes to physically encircle parasites.

Both type I interferon (IFN-I) and T helper 17 (TH17) drive pathology in neuromyelitis optica spectrum disorder (NMOSD) and TH17-induced experimental autoimmune encephalomyelitis (TH17-EAE). This is paradoxical because the prevalent theory is that IFN-I inhibits TH17 function. Here, we identify that IFN-I promotes IL-6 production from B-cells to exacerbate TH17-mediated disease in NMOSD and TH17-EAE. We identified that high levels of IL-17, IFN-I chemokines and IL-6 correlate with severe disability in NMOSD. Furthermore, IL-6 levels were significantly lower in patients treated with anti-CD20 antibody therapy. In mice, IFN-I treatment elevated IL-6 and exacerbated TH17-EAE. Strikingly, therapeutic blockade of IL-6 attenuated disease in IFN-I treated mice. We further demonstrate that IFN-I stimulates B cells to produce IL-6 which in turn drives pathogenic TH17 differentiation. These findings identify potential prognostic biomarkers for NMOSD, define molecular processes behind NMOSD pathogenesis and clarify the paradox surrounding IFN-I and TH17-induced disease.

B cells have emerged as a therapeutic target for multiple sclerosis (MS). Depleting B cells with anti-CD20 antibodies are effective in treating MS. Yet, TACI-Ig treatment, which blocks BAFF and APRIL (two cytokines important for B cell development and function), paradoxically increased disease activity in MS patients. The stark differences in clinical outcomes with these therapies demonstrate that B cells have both inflammatory and regulatory effects in MS. B cell Maturation Antigen (BCMA), a receptor that binds BAFF and APRIL, plays a prominent role in B cell function. The role BCMA plays in MS remains enigmatic and therefore we explored the impact BCMA deficiency has on the development and progression of the experimental autoimmune encephalomyelitis (EAE), a rodent model of MS. We found that EAE induced with MOG35–55 was severe in BCMA−/− mice compared to BCMA+/+ mice. The increased disease was associated with increased CNS inflammation and a skewing of B-cells toward a mature/inflammatory phenotype. Also, for the first time, we observed that BCMA deficiency directly affects the infiltration of inflammatory myeloid cells during EAE. We found that anti-CD20 treatment significantly reduced EAE in BCMA−/− mice but had no effect on BCMA+/+ mice. Conversely, we found that TACI-Ig treatment had no effect on BCMA−/− mice but did reduce EAE in BCMA+/+ mice. Our study demonstrates that BAFF and APRIL constrain the development and function of inflammatory B-cells through BCMA. We further demonstrate that BCMA inhibits inflammatory B cell responses, yet promotes inflammatory responses in macrophages. Finally, our data provide clues into the paradoxical results of clinical trials with anti-CD20 and TACI-Ig in MS patients.

Multiple sclerosis (MS) is immune mediated demyelinating disease of the central nervous system (CNS) leading to neuronal damage. The disease is heterogeneous with respect to onset and clinical course, being more prevalent in women than in men with a ratio of 3:1. Further sex differences have been observed with males having a more severe and debilitating disease course compared to female. The complex interplay of immune cells, sex hormones or genetic differences could be contributing to these clinical phenomena, which remains to be elucidated. In experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, several reports have demonstrated no sex differences in disease onset or severity in C57BL/6 mice. Herein we report that deficiency in B Cell Maturation Antigen (BCMA) in C57BL/6 mice reveals a sex difference in EAE. BCMA plays a prominent role in B cell function, however, the role BCMA plays in MS and EAE is unknown. Our initial goal of this project was to determine the impact BCMA deficiency has on EAE. In doing so we confirmed that EAE disease was not different in males and females from BCMA+/+mice. Strikingly in the BCMA−/− mice, there was a significant increase in EAE disease severity in the males compared to females. The increased EAE in the BCMA−/− male mice was associated with increased demyelination and infiltration of inflammatory T cells and macrophages into CNS. Also, we observed decreased splenic transitional B cells in male BCMA−/− mice compared to females. Altogether, our data demonstrate that male BCMA−/− have elevated inflammatory responses compared to females leading to increased neuro-inflammation. Further experiments are underway to define the specific mechanisms behind the sex differences in BCMA deficient mice.

Type I IFNs (IFN-α and IFN-β) and type II IFN (IFN-γ) mediate both regulation and inflammation in multiple sclerosis, neuromyelitis optica, and in experimental autoimmune encephalomyelitis (EAE). However, the underlying mechanism for these Janus-like activities of type I and II IFNs in neuroinflammation remains unclear. Although endogenous type I IFN signaling provides a protective response in neuroinflammation, we find that when IFN-γ signaling is ablated, type I IFNs drive inflammation, resulting in exacerbated EAE. IFN-γ has a disease stage–specific opposing function in EAE. Treatment of mice with IFN-γ during the initiation phase of EAE leads to enhanced severity of disease. In contrast, IFN-γ treatment during the effector phase attenuated disease. This immunosuppressive activity of IFN-γ required functional type I IFN signaling. In IFN-α/β receptor–deficient mice, IFN-γ treatment during effector phase of EAE exacerbated disease. Using an adoptive transfer EAE model, we found that T cell–intrinsic type I and II IFN signals are simultaneously required to establish chronic EAE by encephalitogenic Th1 cells. However, in Th17 cells loss of either IFN signals leads to the development of a severe chronic disease. The data imply that type I and II IFN signals have independent but nonredundant roles in restraining encephalitogenic Th17 cells in vivo. Collectively, our data show that type I and II IFNs function in an integrated manner to regulate pathogenesis in EAE.

In chronically inflamed tissues, such as those affected by autoimmune disease, activated Th cells often colocalize with monocytes. We investigate in this study how murine Th cells influence the phenotype and function of monocytes. The data demonstrate that Th1, Th2, and Th17 subsets promote the differentiation of autologous monocytes into MHC class II+, CD11b+, CD11c+ DC that we call DCTh. Although all Th subsets induce the formation of DCTh, activated Th17 cells uniquely promote the formation of IL-12/IL-23–producing DCTh (DCTh17) that can polarize both naive and Th17 cells to a Th1 phenotype. In the inflamed CNS of mice with Th17-mediated experimental autoimmune encephalomyelitis, Th cells colocalize with DC, as well as monocytes, and the Th cells obtained from these lesions drive the formation of DCTh that are phenotypically indistinguishable from DCTh17 and polarize naive T cells toward a Th1 phenotype. These results suggest that DCTh17 are critical in the interplay of Th17- and Th1-mediated responses and may explain the previous finding that IL-17–secreting Th cells become IFN-γ–secreting Th1 cells in experimental autoimmune encephalomyelitis and other autoimmune disorders.

Item does not contain fulltext Four questions were posed about multiple sclerosis (MS) at the 2011 Charcot Lecture, Oct. 22, 2011. 1. The Male/Female Disparity: Why are women developing MS so much more frequently than men? 2. Neuronal and Glial Protection: Are there guardian molecules that protect the nervous system in MS? 3. Predictive Medicine: With all the approved drugs, how can we rationally decide which one to use? 4. The Precise Scalpel vs. the Big Hammer for Therapy: Is antigen-specific therapy for demyelinating disease possible? To emphasize how our views on the pathogenesis and treatment of MS are evolving, and given the location of the talk in Amsterdam, Piet Mondrian's progressive interpretations of trees serve as a heuristic.

Purpose Optic neuritis, inflammation of the optic nerve, is experienced by most patients with multiple sclerosis (MS) and is typically characterized by episodes of acute, monocular vision loss. These episodes of inflammation can lead to damage or degeneration of the retinal ganglion cells (RGCs), the axons of which comprise the optic nerve. Experimental autoimmune encephalomyelitis (EAE) is a well-established model of MS in which mice are immunized to produce a neuroautoimmunity that recapitulates the cardinal hallmarks of human disease, namely, inflammation, demyelination, and neurodegeneration of the brain, spinal cord, and optic nerve. Inflammation-associated oxidative stress plays a key role in promoting spinal cord damage in EAE. However, the role of oxidative stress in optic neuritis and the associated visual deficits has not been studied. To address this gap in research, we sought to determine how a deficiency in the master antioxidant transcription factor (using nuclear factor-E2-related factor [Nrf2]-deficient mice) affects visual pathology in the EAE model. Methods EAE was induced in 8-week-old wild-type (WT) and Nrf2 knockout (KO) mice by immunization against the myelin oligodendrocyte glycoprotein (MOG) peptide antigen. Motor deficits were monitored daily, as was visual acuity using the established functional optokinetic tracking (OKT) assay. Mice were euthanized 21 days post-immunization for histological analyses. The optic nerves were paraffin-embedded and stained with hematoxylin and eosin (H&E) or immune cell type–specific antibodies to analyze inflammatory infiltrates. The retinas were flatmounted and stained with an RGC-specific antibody, and the RGCs were counted to assess neurodegeneration. T-helper (Th) cell-associated cytokines were measured in spleens with enzyme-linked immunosorbent assay (ELISA). Immune analyses of healthy, non-EAE mice were characterized with flow cytometry to assess the baseline immune cell profiles. Results Female Nrf2 KO mice exhibited more severe EAE-induced motor deficits compared with female WT mice. In both genders, EAE elicited more severe visual acuity deficits, inflammation of the optic nerve, and RGC degeneration in KO mice compared with their strain- and age-matched WT counterparts. Visual acuity deficits were primarily present in (and only exacerbated in) one eye of each mouse. Excess inflammatory cells within the optic nerves of the KO mice were primarily comprised of T-cells, and greater RGC degeneration in the KO mice was most prevalent in the central retina compared with the peripheral retina. Nrf2 KO spleens exhibited an increased Th1- but not Th17-associated immune response. This enhanced pathology in the KO mice was not due to global differences in immune system development between the two genotypes. Conclusions This is the first study to report that genetic ablation of Nrf2 exacerbates visual deficits, inflammation of the optic nerve, and RGC degeneration in a murine model of MS, suggesting that Nrf2 plays a neuro- and cytoprotective role in EAE-associated optic neuritis.

CD47 exerts different effects on disease in distinct cell types and locations and during different stages of experimental autoimmune encephalomyelitis., Comparison of transcriptomic and proteomic data from pathologically similar multiple sclerosis (MS) lesions reveals down-regulation of CD47 at the messenger RNA level and low abundance at the protein level. Immunohistochemical studies demonstrate that CD47 is expressed in normal myelin and in foamy macrophages and reactive astrocytes within active MS lesions. We demonstrate that CD47−/− mice are refractory to experimental autoimmune encephalomyelitis (EAE), primarily as the result of failure of immune cell activation after immunization with myelin antigen. In contrast, blocking with a monoclonal antibody against CD47 in mice at the peak of paralysis worsens EAE severity and enhances immune activation in the peripheral immune system. In vitro assays demonstrate that blocking CD47 also promotes phagocytosis of myelin and that this effect is dependent on signal regulatory protein α (SIRP-α). Immune regulation and phagocytosis are mechanisms for CD47 signaling in autoimmune neuroinflammation. Depending on the cell type, location, and disease stage, CD47 has Janus-like roles, with opposing effects on EAE pathogenesis.

In multiple sclerosis, type I interferon (IFN) is considered immune-modulatory, and recombinant forms of IFN-β are the most prescribed treatment for this disease. This is in contrast to most other autoimmune disorders, because type I IFN contributes to the pathologies. Even within the relapsing-remitting multiple sclerosis (RRMS) population, 30-50% of MS patients are non-responsive to this treatment, and it consistently worsens neuromyelitis optica, a disease similar to RRMS. In this article, we discuss the recent advances in the field of autoimmunity and introduce the theory explain how type I IFNs can be pro-inflammatory in disease that is predominantly driven by a Th17 response and are therapeutic when disease is predominantly Th1.

Background: The pathology of neuromyelitis optica (NMO), in contrast to multiple sclerosis, comprises granulocyte infiltrates along extensive lengths of spinal cord, as well as optic nerve. Furthermore, IFN-β treatment worsens NMO. We recently found that experimental autoimmune encephalomyelitis (EAE) induced with Th17 cells is exacerbated by IFN-β, in contrast to disease induced with Th1 where treatment attenuated symptoms. Objective: This study demonstrates the similarities between NMO and Th17 EAE and how neutrophils mediate pathology in Th17 disease. Methods: Levels of blood biomarkers in NMO were assessed by Luminex and ELISA. Effects of IFN-β on neutrophils were assessed by culture assays and immunofluorescence. EAE was induced by transfer of myelin-specific Th1 or Th17 cells and treated with Sivelestat sodium hydrate, a neutrophil elastase inhibitor. Results: We show Th17 cytokines, granulocyte chemokines, type 1 interferon and neutrophil elastase are elevated in patients with definitive NMO. In culture, we find that IFN-β stimulates neutrophils to release neutrophil elastase. In Th17 EAE, we demonstrate neutrophilic infiltration in the optic nerve and spinal cord which was not present in Th1 EAE. Blockade of neutrophil elastase with Sivelestat had efficacy in Th17 EAE but not Th1 EAE. Conclusions: The similarities between Th17 EAE and NMO indicate that this model represents several aspects of NMO. Neutrophils are critical in the pathologies of both Th17-EAE and NMO, and therefore blockade of neutrophil elastase is a promising target in treating NMO.

Background IL-16 promotes the recruitment of various cells expressing CD4, a receptor for IL-16. The precise role of IL-16 in transplant rejection remains unknown; therefore, the present study investigated the contribution of IL-16 to the development of chronic rejection in heart transplants. Methods C-H-2 bm12 KhEg (H-2 bm12 ) donor hearts were transplanted into (1) IL-16-deficient (IL-16 −/− ) C57BL/6J or (b) wild type (WT) control recipients (MHC class II mismatch). Grafts were harvested at 52 days, parenchymal rejection was assessed by the ISHLT grading system, and CAV was examined morphometrically. Graft infiltrating cells were detected 10 and 52 days after transplantation. Intragraft cytokine and chemokine profiles were assessed. To confirm the role of IL-16 in CAV development, C-H-2 bm12 KhEg (H-2 bm12 ) donor hearts were transplanted into C57BL/6J WT recipients treated with (1) anti-IL-16-neutralization monoclonal antibody or (b) control immunoglobulin G. Grafts were harvested at 52 days, and CAV was quantified morphometrically. Graft-infiltrating cells were examined histologically. Results Parenchymal rejection and CAV was significantly attenuated in donor hearts transplanted into IL-16 −/− recipient mice compared with WT controls. Donor hearts transplanted into IL-16 −/− recipients had a significant reduction in coronary artery luminal occlusion, intima-to-media ratio, and percentage of diseased vessels. CAV was associated with decreased donor organ inflammation, as well as donor organ cytokine (IL-1β and IL-6) and chemokine (MCP-1 and KC) protein expression. Intimal proliferation and inflammatory cell infiltration were significantly reduced in hearts transplanted into recipients treated with an IL-16-neutralization antibody. Conclusions IL-16-deficiency reduced graft inflammatory cell recruitment, and allograft inflammatory cytokine and chemokine production. Therefore, IL-16 neutralization may provide a potential target for novel therapeutic treatment for cardiac allograft rejection.

In this study, exosomes used to encapsulate curcumin (Exo-cur) or a signal transducer and activator of transcription 3 (Stat3) inhibitor, i.e., JSI124 (Exo-JSI124) were delivered noninvasively to microglia cells via an intranasal route. The results generated from three inflammation-mediated disease models, i.e., a lipopolysaccharide (LPS)-induced brain inflammation model, experimental autoimmune encephalitis and a GL26 brain tumor model, showed that mice treated intranasally with Exo-cur or Exo-JSI124 are protected from LPS-induced brain inflammation, the progression of myelin oligodendrocyte glycoprotein (MOG) peptide induced experimental autoimmune encephalomyelitis (EAE), and had significantly delayed brain tumor growth in the GL26 tumor model. Intranasal administration of Exo-cur or Exo-JSI124 led to rapid delivery of exosome encapsulated drug to the brain that was selectively taken up by microglial cells, and subsequently induced apoptosis of microglial cells. Our results demonstrate that this strategy may provide a noninvasive and novel therapeutic approach for treating brain inflammatory-related diseases.

Interferon (IFN)-β is the treatment most often prescribed for relapsing-remitting multiple sclerosis (RRMS). 30-50% of MS patients, however, do not respond to IFN-β. In some cases, IFN-β exacerbates MS, and it consistently worsens neuromyelitis optica (NMO). To eliminate unnecessary treatment for patients who are non-responsive to IFN-β, and to avoid possible harm, researchers are identifying biomarkers that predict treatment outcome before treatment is initiated. These biomarkers reveal insights into the mechanisms of disease. Recent discoveries on human samples from patients with RRMS, NMO, psoriasis, rheumatoid arthritis, systemic lupus erythematosus and ulcerative colitis, indicate that IFN-β is ineffective and might worsen clinical status in diverse diseases when a Th17 immune response is prominent.

The cooperative role of T cells and B cells is a topical research area in multiple sclerosis. Previous studies, using experimental autoimmune encephalomyelitis (EAE), have shown that TH17 responses are correlated with ectopic B cell follicles in the CNS. As follicular T helper (TFH) cells control B cell responses, this study examines the role TFH cells play TH17-induced EAE. As previously reported, we found that B cells are a major cell type infiltrating the CNS of mice with TH17-EAE. We now show that the severity TH17-EAE was diminished in B cell deficient mice demonstrating that B cells contribute to the severity of disease in these mice. We next focused on the role TFH cells play in TH17-EAE. We found substantial numbers of TFH cells in the CNS of TH17-EAE mice and these cells are correlated with infiltrating B cells. Using transfer experiments, we found that TFH cells alone do not infiltrate the CNS but require the infiltration of TH17 cells to gain entry to the CNS. We next tested the effects of blocking TFH trafficking in TH17-EAE using an antagonistic antibody against CXCL13, the chemokine that binds to CXCR5 on TFH cells. We found that anti-CXCL13 treatment significantly reduced TH17-EAE disease. This treatment blocked T cells from entering the CNS but had no effect on B cells. Surprisingly, we observed that anti-CXCL13 treatment reduced disease in B cell-deficient mice. Collectively, these data demonstrate that B cells and TFH cells contribute to the severity of TH17-induced EAE. Furthermore, this report describes an important role for TFH cells that is independent of their support for B cell function and begins to answer important questions regarding their contribution in neuro-inflammatory diseases.

B cells have emerged as a therapeutic target for multiple sclerosis (MS). Depleting B cells with anti-CD20 antibodies are effective in treating MS. Yet, blockade of BAFF and APRIL, two cytokines important for B cell development and function, paradoxically increased disease activity in MS patients. The stark differences in clinical outcomes with these therapies demonstrate that B cells have both inflammatory and regulatory effects in MS. B cell Maturation Antigen (BCMA), a receptor that binds both BAFF and APRIL, plays a prominent role in B cell function. The role BCMA plays in MS remains enigmatic and therefore we designed this study to explore the impact BCMA deficiency has on the development and progression of experimental autoimmune encephalomyelitis (EAE), a rodent model of MS. We found that EAE induced with MOG35–55 was more severe in BCMA−/− mice compared to BCMA+/+ mice. The increased disease was associated with increased CNS inflammation and a skewing of B-cells toward a mature/inflammatory phenotype. Using bone marrow chimera strategies, we found that BCMA deficiency in B-cells was responsible for the increase in disease severity. Next, we found that anti-CD20 treatment significantly reduced EAE in BCMA−/− mice but had no effects on BCMA+/+ mice. Conversely, we found that TACI-Ig treatment had no effect on BCMA−/− mice but did reduce EAE in BCMA+/+ mice. Our data demonstrate that BAFF and APRIL constrains the development and function of inflammatory B-cells through BCMA. Furthermore, our data provide clues into the paradoxical results of clinical trials with anti-CD20 and TACI-Ig in MS.

Interferon (IFN)-β is a popular therapy for multiple sclerosis (MS). However, neuro-autoimmune diseases that have strong T Helper (TH) 17 signatures are exacerbated with IFN-β; these includes MS patients who are non-responders to IFN-β and patients with neuromyelitis optica (NMO). Previous studies using experimental autoimmune encephalomyelitis (EAE) demonstrated that IFN-β treatment has exacerbated TH17-induced disease. These results are confounding because one proposed mechanism of the efficacy of IFN-β treatment is that it inhibits IL-17 expression in T-cells. Our objective is to elucidate the conflicting theories on how IFN-β affects TH17 function. Here, we demonstrate that IFN-β enhances the effects of IL-23 on TH17 cells and promotes their pathogenicity by elevating the expression of TH1 and TH17 genes as well as GM-CSF. We next determined the precise cellular mechanism by which IFN-β drives an inflammatory TH17 response. We found that the IFN-β exerts its inflammatory effect by directly acting on B cells which in turn effected the function of T helper cells. Specifically, we found that IFN-β elevates the expression of the co-stimulatory receptors CD80 and CD86 as well as the inflammatory cytokine IL-6 in B-cells. Furthermore, we found that B cells previously stimulated with IFN-β drive the differentiation of myelin-specific TH17 cells, which secrete the inflammatory cytokines GM-CSF, IL-17A, IFNγ and IL-6. Taken together, these findings resolve a mechanistic paradox surrounding type 1 interferon and TH17-induced disease and illuminates possible cellular pathways responsible for the pathophysiology of NMO and of MS patients who are IFN-β non-responders.

Background Although interleukin-17 (IL-17) has been reported to participate in the pathogenesis of infectious, autoimmune and allergic disorders, the precise role in allograft rejection remains uncertain. This study illustrates that IL-17 contributes to the pathogenesis of chronic allograft rejection. Result Utilizing a murine heterotopic heart transplant model system, IL-17-deficient recipient mice had decreased allograft inflammatory cell recruitment, decreased IL-6, MCP-1, and KC production, and reduced graft coronary artery disease (GCAD). Intragraft gamma delta (γδ) T cells appear to be the predominant source of IL-17 production. Conclusion Therefore, IL-17 neutralization may provide a potential target for novel therapeutic treatment for cardiac allograft rejection.

Purpose Optic neuritis affects most patients with multiple sclerosis (MS), and current treatments are unreliable. The purpose of this study was to characterize the contribution of Th1 and Th17 cells to the development of optic neuritis. Methods Mice were passively transferred myelin-specific Th1 or Th17 cells to induce experimental autoimmune encephalomyelitis (EAE), a model of neuroautoimmunity. Visual acuity was assessed daily with optokinetic tracking, and 1, 2, and 3 weeks post-induction, optic nerves and retinas were harvested for immunohistochemical analyses. Results Passive transfer experimental autoimmune encephalomyelitis elicits acute episodes of asymmetric visual deficits and is exacerbated in Th17-EAE relative to Th1-EAE. The Th17-EAE optic nerves contained more inflammatory infiltrates and an increased neutrophil to macrophage ratio. Significant geographic degeneration of the retinal ganglion cells accompanied Th17-EAE but not Th1. Conclusions Th17-induced transfer EAE recapitulates pathologies observed in MS-associated optic neuritis, namely, monocular episodes of vision loss, optic nerve inflammation, and geographic retinal ganglion cell (RGC) degeneration.