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

Pro-Resolving Macrophage-Induced IL-35+ but Not TGF-β1+ Regulatory B Cell Activation Requires the PD-L1/PD-1 Pathway

The interaction between immune regulatory cells, such as regulatory B cells (Breg) and pro-resolving macrophages (M2 macrophages), plays an important role in the restoration of immune homeostasis during inflammation. PD-L1 is one of the effector molecules that mediates the immune regulation function of M2 macrophages. The activation of PD-L1/PD-1 signaling promotes the differentiation of Breg. Previous studies have shown that Breg promoted M2 macrophage polarization and enhanced their function, but little is known about the regulatory function of M2 macrophages on Breg differentiation. This study aims to determine the effect of M2 macrophages on Breg induction and the potential mechanism in vitro. Bone-marrow-derived macrophages were isolated from wild-type (WT) mice and polarized into M2 using IL-4/IL-13. To investigate the role of PD-L1/PD-1 in M2 macrophage-induced Breg differentiation, spleen B cells were isolated from WT or PD-1 knockout (KO) mice and co-cultured with either naïve (M0) or M2 macrophages for 48 h with or without trans-well inserts. The expression of IL-10, IL-35, and TGF-β1 in B cells was evaluated by flow cytometry and immunofluorescence staining. Recombinant PD-L1 was used to stimulate activated B cells, followed by the detection of IL-35 and TGF-β1. The results show that there was no significant difference in IL-10 expression among all groups. However, IL-35 and TGF-β1 expression in B cells was significantly increased in the M2+B, but not in M0+B, compared to B cells alone. Notably, such increases were diminished when M2 and B cells were separated by trans-well inserts. IL-35 expression was not significantly changed when B cells from PD-1 KO mice were co-cultured with M2 compared to the control. However, TGF-β1 expression was significantly increased when PD-1 KO B cells were co-cultured with M2 compared to the control. IL-35 expression in activated B cells was increased upon stimulation with PD-L1. However, TGF-β1 expression in activated B cells was increased regardless of the PD-L1 availability. This study demonstrates that pro-resolving macrophage-induced IL-35+ but not TGF-β1+ regulatory B cell activation requires the PD-L1/PD-1 pathway.

Tumor-infiltrating and circulating B cells mediate local and systemic immunomodulatory mechanisms in Glioblastoma

BACKGROUND

Glioblastoma (GBM) demonstrates extensive immunomodulatory mechanisms that challenge effective therapeutic interventions. These phenomena extend well beyond the tumor microenvironment (TME) and are reflected in the circulating immunophenotype. B lymphocytes (B cells) have received limited attention in GBM studies despite their emerging importance in mediating both local and systemic immune responses. Recent findings highlight the complex regulatory interactions between B cells and other immune cell populations, including tumor-infiltrating macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and other infiltrating lymphocytes (TILs). B cells are believed to hinder the efficacy of modern immunotherapy strategies focusing on T cells.

METHODS

This is a focused review of available evidence regarding B cells in GBM through January 2025.

RESULTS

Peripheral blood reflects a systemically dampened immune response, with sustained lymphopenia, increased plasma cells, and dysfunctional memory B cells. The tumor immune landscape is enriched in cells of B-lineage. Subsets of poorly characterized B regulatory cells (Bregs) populate the TME, developing their phenotype due to their proximity to MDSCs, TAMs, and tumoral cells. The Bregs inhibit CD8+ T activity and may have potential prognostic significance.

CONCLUSION

Understanding the role of B cells, how they are recruited, and their differentiation shifted towards an immunomodulatory role could inform better therapeutic strategies and unleash their full antitumoral potential in GBM.

Arketamine alleviates cognitive impairments and demyelination in mice with postoperative cognitive dysfunction via TGF-β1 activation

Postoperative cognitive dysfunction (POCD) is characterized by a decline in cognitive functions, including memory, attention, and executive abilities, following surgery, with no effective therapeutic drugs currently available. Arketamine, the (R)-enantiomer of ketamine, has shown promise in mitigating cognitive deficits in animal models. In this study, we investigated whether arketamine could ameliorate cognitive deficits in a mouse model of POCD, with a focus on the role of transforming growth factor (TGF)-β1 in its effects. POCD mice displayed cognitive impairments and demyelination in the corpus callosum. A single arketamine injection (10 mg/kg) significantly improved both cognitive function and demyelination in the corpus callosum of POCD mice. Notably, pretreatment with RepSox (10 mg/kg), a TGF-β receptor 1 inhibitor, significantly blocked the beneficial effects of arketamine on cognitive deficits and demyelination. Moreover, intranasal administration of TGF-β1 (3.0 μg/kg) markedly alleviated cognitive impairments and demyelination in POCD mice. These findings suggest that arketamine exerts its effects through a TGF-β1-dependent mechanism, positioning it as a potential therapeutic option for POCD.

Effects of arketamine on depression-like behaviors and demyelination in mice exposed to chronic restrain stress: A role of transforming growth factor-β1

BACKGROUND

Chronic restrain stress (CRS) induces depression-like behaviors and demyelination in the brain; however, the relationship between these depression-like behaviors and demyelination remains unclear. Arketamine, the (R)-enantiomer of ketamine, has shown rapid antidepressant-like effects in CRS-exposed mice.

METHODS

We examined whether arketamine can improve both depression-like behaviors and demyelination in the brains of CRS-exposed mice. Additionally, we investigated the role of transforming growth factor β1 (TGF-β1) in the beneficial effects of arketamine.

RESULTS

A single dose of arketamine (10 mg/kg) improved both depression-like behavior and demyelination in the corpus callosum of CRS-exposed mice. Correlations were found between depression-like behaviors and demyelination in this region. Furthermore, pretreatment with RepSox, an inhibitor of TGF-β1 receptor, significantly blocked the beneficial effects of arketamine on depression-like behaviors and demyelination in CRS-exposed mice. Finally, a single intranasal administration of TGF-β1 ameliorated both depression-like behaviors and demyelination in CRS-exposed mice.

LIMITATIONS

The precise mechanisms by which TGF-β1 contributes to the effects of arketamine remain unclear.

CONCLUSIONS

These data suggest that CRS-induced demyelination in the corpus callosum may contribute to depression-like behaviors, and that arketamine can mitigate these changes through a TGF-β1-dependent mechanism.

Transforming growth factor-β1 mediates the beneficial effects of arketamine on demyelination and remyelination in the brains of cuprizone-treated mice

The novel antidepressant arketamine, the (R)-enantiomer of ketamine, has been shown to ameliorate demyelination and facilitate remyelination in the brains of cuprizone (CPZ)-treated mice. However, the mechanisms behind its effects remain unclear. Given the role of transforming growth factor β1 (TGF-β1) in arketamine's antidepressant-like effects, we examined whether TGF-β1 also plays a role in arketamine's effects on demyelination and remyelination in CPZ-treated mice. Additionally, we investigated the effects of intranasal TGF-β1 on demyelination and remyelination in these mice. Repeated intermittent administration of arketamine (10 mg/kg/day, twice weekly for the last 2-weeks) attenuated demyelination in the corpus callosum (CC) of CPZ (6 weeks)-treated mice. Furthermore, pretreatment with RepSox (10 mg/kg/day), an inhibitor of the TGF-β receptor 1, significantly blocked the beneficial effects of arketamine on the demyelination in the CC of CPZ-treated mice. Additionally, repeated intermittent administration of TGF-β1 (3.0 μg/kg/day, twice weekly for 2 weeks) significantly ameliorated demyelination and facilitated remyelination in the CC of CPZ-treated mice. These data suggest that arketamine can mitigate demyelination and facilitates remyelination in the brains of CPZ-treated mice through a TGF-β1-dependent mechanism.

The current understanding of the phenotypic and functional properties of human regulatory B cells (Bregs)

B cells can have a wide range of pro- and anti- inflammatory functions. A subset of B cells called regulatory B cells (Bregs) can potently suppress immune responses. Bregs have been shown to maintain immune homeostasis and modulate inflammatory responses. Bregs are an exciting cellular target across a range of diseases, including Breg induction in autoimmunity, allergy and transplantation, and Breg suppression in cancers and infection. Bregs exhibit a remarkable phenotypic heterogeneity, rendering their unequivocal identification a challenging task. The lack of a universally accepted and exclusive surface marker set for Bregs across various studies contributes to inconsistencies in their categorization. This review paper presents a comprehensive overview of the current understanding of the phenotypic and functional properties of human Bregs while addressing the persisting ambiguities and discrepancies in their characterization. Finally, the paper examines the promising therapeutic opportunities presented by Bregs as their immunomodulatory capacities have gained attention in the context of autoimmune diseases, allergic conditions, and cancer. We explore the exciting potential in harnessing Bregs as potential therapeutic agents and the avenues that remain open for the development of Breg-based treatment strategies.

Evidence for TGF-β1/Nrf2 Signaling Crosstalk in a Cuprizone Model of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic and degenerative disease that impacts central nervous system (CNS) function. One of the major characteristics of the disease is the presence of regions lacking myelin and an oxidative and inflammatory environment. TGF-β1 and Nrf2 proteins play a fundamental role in different oxidative/inflammatory processes linked to neurodegenerative diseases such as MS. The evidence from different experimental settings has demonstrated a TGF-β1-Nrf2 signaling crosstalk under pathological conditions. However, this possibility has not been explored in experimental models of MS. Here, by using the cuprizone-induced demyelination model of MS, we report that the in vivo pharmacological blockage of the TGF-β1 receptor reduced Nrf2, catalase, and TGFβ-1 protein levels in the demyelination phase of cuprizone administration. In addition, ATP production, locomotor function and cognitive performance were diminished by the treatment. Altogether, our results provide evidence for a crosstalk between TGF-β1 and Nrf2 signaling pathways under CNS demyelination, highlighting the importance of the antioxidant cellular response of neurodegenerative diseases such as MS.

Human regulatory memory B cells defined by expression of TIM-1 and TIGIT are dysfunctional in multiple sclerosis

Background

Regulatory B cells (Bregs) play a pivotal role in suppressing immune responses, yet there is still a lack of cell surface markers that can rigorously identify them. In mouse models for multiple sclerosis (MS), TIM-1 or TIGIT expression on B cells is required for maintaining self-tolerance and regulating autoimmunity to the central nervous system. Here we investigated the activities of human memory B cells that differentially express TIM-1 and TIGIT to determine their potential regulatory function in healthy donors and patients with relapsing-remitting (RR) MS.

Methods

FACS-sorted TIM-1+/-TIGIT+/- memory B (memB) cells co-cultured with allogenic CD4+ T cells were analyzed for proliferation and induction of inflammatory markers using flow cytometry and cytokine quantification, to determine Th1/Th17 cell differentiation. Transcriptional differences were assessed by SMARTSeq2 RNA sequencing analysis.

Results

TIM-1-TIGIT- double negative (DN) memB cells strongly induce T cell proliferation and pro-inflammatory cytokine expression. The TIM-1+ memB cells enabled low levels of CD4+ T cell activation and gave rise to T cells that co-express IL-10 with IFNγ and IL-17A or FoxP3. T cells cultured with the TIM-1+TIGIT+ double positive (DP) memB cells exhibited reduced proliferation and IFNγ, IL-17A, TNFα, and GM-CSF expression, and exhibited strong regulation in Breg suppression assays. The functional activity suggests the DP memB cells are a bonafide Breg population. However, MS DP memB cells were less inhibitory than HC DP memB cells. A retrospective longitudinal study of anti-CD20 treated patients found that post-treatment DP memB cell frequency and absolute number were associated with response to therapy. Transcriptomic analyses indicated that the dysfunctional MS-derived DP memB/Breg population exhibited increased expression of genes associated with T cell activation and survival (CD80, ZNF10, PIK3CA), and had distinct gene expression compared to the TIGIT+ or TIM-1+ memB cells.

Conclusion

These findings demonstrate that TIM-1/TIGIT expressing memory B cell subsets have distinct functionalities. Co-expression of TIM-1 and TIGIT defines a regulatory memory B cell subset that is functionally impaired in MS.

Single-cell analysis of age-related changes in leukocytes of diabetic mouse hindpaws

Complications associated with Type 1 and Type 2 diabetes, such as diabetic peripheral neuropathy and diabetic foot ulcers, are a growing health-care concern. In addition, this concern increases as diabetic patients age due to their increased susceptibility to complications. To address this growing problem, it is important to understand fluctuations in physiology which lead to pathological changes associated with the metabolic disturbances of diabetes. Our study explores dysregulation of immune cell populations in the hindpaws of healthy and diabetic mice at 12 and 21 weeks of age using single-cell RNA sequencing to provide insight into immune disruptions occurring in the distal limb during chronic diabetes. In 21-week-old Leprdb/db mice, increases were seen in mast cells/basophils, dermal γδ T cells, heterogeneous T cells, and Type 2 innate lymphoid cells. In addition, macrophages represented the largest cluster of immune cells and showed the greatest increase in genes associated with immune-specific pathways. Sub-clustering of macrophages revealed a bias toward angiogenic Lyve1+MHCIIlo macrophages in the hindpaws of 21-week-old diabetic mice, which corresponded to an increase in Lyve1+ macrophages in the hindpaws of 21-week-old diabetic mice on histology. Our results show that in Type 2 diabetes, the immunological function and phenotype of multiple immune cell types shift not only with metabolic disturbance, but also with duration of disease, which may explain the increased susceptibility to pathologies of the distal limb in patients with more chronic diabetes.

Breg-Mediated Immunoregulation in the Skin

Wound healing is a complex process involving a coordinated series of events aimed at restoring tissue integrity and function. Regulatory B cells (Bregs) are a subset of B lymphocytes that play an essential role in fine-tuning immune responses and maintaining immune homeostasis. Recent studies have suggested that Bregs are important players in cutaneous immunity. This review summarizes the current understanding of the role of Bregs in skin immunity in health and pathology, such as diabetes, psoriasis, systemic sclerosis, cutaneous lupus erythematosus, cutaneous hypersensitivity, pemphigus, and dermatomyositis. We discuss the mechanisms by which Bregs maintain tissue homeostasis in the wound microenvironment through the promotion of angiogenesis, suppression of effector cells, and induction of regulatory immune cells. We also mention the potential clinical applications of Bregs in promoting wound healing, such as the use of adoptive Breg transfer.

Delimiting MOGAD as a disease entity using translational imaging

The first formal consensus diagnostic criteria for myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) were recently proposed. Yet, the distinction of MOGAD-defining characteristics from characteristics of its important differential diagnoses such as multiple sclerosis (MS) and aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder (NMOSD) is still obstructed. In preclinical research, MOG antibody-based animal models were used for decades to derive knowledge about MS. In clinical research, people with MOGAD have been combined into cohorts with other diagnoses. Thus, it remains unclear to which extent the generated knowledge is specifically applicable to MOGAD. Translational research can contribute to identifying MOGAD characteristic features by establishing imaging methods and outcome parameters on proven pathophysiological grounds. This article reviews suitable animal models for translational MOGAD research and the current state and prospect of translational imaging in MOGAD.

Immunological mechanisms of tolerance: Central, peripheral and the role of T and B cells

T and B cells are key components of the adaptive immune system. Through their immune properties and their interactions with other immune cells and cytokines around them, they build a complex network to achieve immune tolerance and maintain homeostasis of the body. This is achieved through mechanisms of central and peripheral tolerance, both of which are associated with advantages and disadvantages. For this reason, the immune system is tightly regulated and their dysregulation can result in the subsequent initiation of various diseases. In this review, we will summarize the roles played by T cells and B cells within immune tolerance with specific examples in the context of different diseases that include allergic disease. In addition, we will also provide an overview on their suitability as biomarkers of allergen-specific immunotherapy.

Intricacies of TGF-β signaling in Treg and Th17 cell biology

Balanced immunity is pivotal for health and homeostasis. CD4+ helper T (Th) cells are central to the balance between immune tolerance and immune rejection. Th cells adopt distinct functions to maintain tolerance and clear pathogens. Dysregulation of Th cell function often leads to maladies, including autoimmunity, inflammatory disease, cancer, and infection. Regulatory T (Treg) and Th17 cells are critical Th cell types involved in immune tolerance, homeostasis, pathogenicity, and pathogen clearance. It is therefore critical to understand how Treg and Th17 cells are regulated in health and disease. Cytokines are instrumental in directing Treg and Th17 cell function. The evolutionarily conserved TGF-β (transforming growth factor-β) cytokine superfamily is of particular interest because it is central to the biology of both Treg cells that are predominantly immunosuppressive and Th17 cells that can be proinflammatory, pathogenic, and immune regulatory. How TGF-β superfamily members and their intricate signaling pathways regulate Treg and Th17 cell function is a question that has been intensely investigated for two decades. Here, we introduce the fundamental biology of TGF-β superfamily signaling, Treg cells, and Th17 cells and discuss in detail how the TGF-β superfamily contributes to Treg and Th17 cell biology through complex yet ordered and cooperative signaling networks.

IL-10-providing B cells govern pro-inflammatory activity of macrophages and microglia in CNS autoimmunity

B cells contribute to chronic inflammatory conditions as source of antibody-secreting plasma cells and as antigen-presenting cells activating T cells, making anti-CD20-mediated B cell depletion a widely used therapeutic option. B cells or B cell subsets may, however, exert regulatory effects, while to date, the immunological and/or clinical impact of these observations remained unclear. We found that in multiple sclerosis (MS) patients, B cells contain regulatory features and that their removal enhanced activity of monocytes. Using a co-culture system, we identified B cell-provided interleukin (IL)-10 as key factor in controlling pro-inflammatory activity of peripheral myeloid cells as well as microglia. Depleting B cells via anti-CD20 in a mouse model of MS unleashed the activity of myeloid cells and microglia and accelerated disease severity; in contrast, adoptive transfer of IL-10-providing B cells restored in vivo control of central nervous system (CNS) macrophages and microglia and reversed clinical exacerbation. These findings suggest that B cells exert meaningful regulatory properties, which should be considered when designing novel B cell-directed agents.

Immune modulation after traumatic brain injury

Traumatic brain injury (TBI) induces instant activation of innate immunity in brain tissue, followed by a systematization of the inflammatory response. The subsequent response, evolved to limit an overwhelming systemic inflammatory response and to induce healing, involves the autonomic nervous system, hormonal systems, and the regulation of immune cells. This physiological response induces an immunosuppression and tolerance state that promotes to the occurrence of secondary infections. This review describes the immunological consequences of TBI and highlights potential novel therapeutic approaches using immune modulation to restore homeostasis between the nervous system and innate immunity.

Current Perspectives: Evidence to Date on BTK Inhibitors in the Management of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system leading to demyelination and neurodegeneration. Basic and translational studies have shown that B cells and myeloid cells are critical players for the development and course of the disease. Bruton's tyrosine kinase (BTK) is essential for B cell receptor-mediated B cell activation and for normal B cell development and maturation. In addition to its role in B cells, BTK is also involved in several functions of myeloid cells. Although significant number of disease-modifying treatments (DMTs) have been approved for clinical use in MS patients, novel targeted therapies should be studied in refractory patients and patients with progressive forms of the disease. On the basis of its role in B cells and myeloid cells, BTK inhibitors can provide attractive therapeutic benefits for MS. In this article, we review the main effects of BTK inhibitors on different cell types involved in the pathogenesis of MS and summarise recent advances in the development of BTK inhibitors as novel therapeutic approaches in different MS clinical trials. Available data regarding the efficacy and safety of these drugs are described.

Suppressive mechanisms of regulatory B cells in mice and humans

B cells include immune-suppressive fractions, called regulatory B cells (Bregs), which regulate inflammation primarily through an interleukin 10 (IL-10)-mediated inhibitory mechanism. Several B-cell fractions have been reported as IL-10-producing Bregs in murine disease models and human inflammatory responses including autoimmune diseases, infectious diseases, cancer and organ-transplant rejection. Although the suppressive functions of Bregs have been explored through the hallmark molecule IL-10, inhibitory cytokines and membrane-binding molecules other than IL-10 have also been demonstrated to contribute to Breg activities. Transcription factors and surface antigens that are characteristically expressed in Bregs are also being elucidated. Nevertheless, defining Bregs is still challenging because their active periods and differentiation stages vary among disease models. The identity of the diverse Breg fractions is also under debate. In the first place, since regulatory functions of Bregs are mostly evaluated by ex vivo stimulation, the actual in vivo phenotypes and functions may not be reflected by the ex vivo observations. In this article, we provide a historical overview of studies that established the characteristics of Bregs and review the various suppressive mechanisms that have been reported to be used by Bregs in murine and human disease conditions. We are only part-way through but the common phenotypes and functions of Bregs are still emerging.

Enriched circulating and tumor-resident TGF-β+ regulatory B cells in patients with melanoma promote FOXP3+ Tregs

B cells are emerging as key players of anti-tumor adaptive immune responses. We investigated regulatory and pro-inflammatory cytokine-expressing B cells in patients with melanoma by flow cytometric intracellular cytokine, CyTOF, transcriptomic, immunofluorescence, single-cell RNA-seq, and B:T cell co-culture analyses. We found enhanced circulating regulatory (TGF-β⁺ and PD-L1⁺) and reduced pro-inflammatory TNF-α⁺ B cell populations in patients compared with healthy volunteers (HVs), including lower IFN-γ⁺:IL-4⁺ and higher TGF-β⁺:TNF-α⁺ B cell ratios in patients. TGF-β-expressing B cells in the melanoma tumor microenvironment assembled in clusters and interacted with T cells via lymphoid recruitment (SELL, CXCL13, CCL4, CD74) signals and with Tregs via CD47:SIRP-γ, and FOXP3-promoting Galectin-9:CD44. While reduced in tumors compared to blood, TNF-α-expressing B cells engaged in crosstalk with Tregs via TNF-α signaling and the ICOS/ICOSL axis. Patient-derived B cells promoted FOXP3⁺ Treg differentiation in a TGF-β-dependent manner, while sustaining expression of IFN-γ and TNF-α by autologous T-helper cells and promoting T-helper cell proliferation ex vivo, an effect further enhanced with anti-PD-1 checkpoint blockade. Our findings reveal cytokine-expressing B cell compartments skewed toward regulatory phenotypes in patient circulation and melanoma lesions, intratumor spatial localization, and bidirectional crosstalk between B and T cell subsets with immunosuppressive attributes.

Molecular Mechanisms Driving IL-10- Producing B Cells Functions: STAT3 and c-MAF as Underestimated Central Key Regulators?

Regulatory B cells (Bregs) have been highlighted in very different pathology settings including autoimmune diseases, allergy, graft rejection, and cancer. Improving tools for the characterization of Bregs has become the main objective especially in humans. Transitional, mature B cells and plasma cells can differentiate into IL-10 producing Bregs in both mice and humans, suggesting that Bregs are not derived from unique precursors but may arise from different competent progenitors at unrestricted development stages. Moreover, in addition to IL-10 production, regulatory B cells used a broad range of suppressing mechanisms to modulate the immune response. Although Bregs have been consistently described in the literature, only a few reports described the molecular aspects that control the acquisition of the regulatory function. In this manuscript, we detailed the latest reports describing the control of IL-10, TGFβ, and GZMB production in different Breg subsets at the molecular level. We focused on the understanding of the role of the transcription factors STAT3 and c-MAF in controlling IL-10 production in murine and human B cells and how these factors may represent an important crossroad of several key drivers of the Breg response. Finally, we provided original data supporting the evidence that MAF is expressed in human IL-10- producing plasmablast and could be induced in vitro following different stimulation cocktails. At steady state, we reported that MAF is expressed in specific human B-cell tonsillar subsets including the IgD⁺ CD27⁺ unswitched population, germinal center cells and plasmablast.

B cells in central nervous system disease: diversity, locations and pathophysiology

B cells represent a relatively minor cell population within both the healthy and diseased central nervous system (CNS), yet they can have profound effects. This is emphasized in multiple sclerosis, in which B cell-depleting therapies are arguably the most efficacious treatment for the condition. In this Review, we discuss how B cells enter and persist in the CNS and how, in many neurological conditions, B cells concentrate within CNS barriers but are rarely found in the parenchyma. We highlight how B cells can contribute to CNS pathology through antibody secretion, antigen presentation and secretion of neurotoxic molecules, using examples from CNS tumours, CNS infections and autoimmune conditions such as neuromyelitis optica and, in particular, multiple sclerosis. Overall, understanding common and divergent principles of B cell accumulation and their effects within the CNS could offer new insights into treating these devastating neurological conditions.

A systematic review of molecular approaches that link mitochondrial dysfunction and neuroinflammation in Parkinson's disease

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder that affects 1% of the population worldwide. Etiology of PD is likely to be multi-factorial such as protein misfolding, mitochondrial dysfunction, oxidative stress, and neuroinflammation that contributes to the pathology of Parkinson's disease (PD), numerous studies have shown that mitochondrial dysfunction may play a key role in the dopaminergic neuronal loss. In multiple ways, the two most important are the activation of neuroinflammation and mitochondrial dysfunction, while mitochondrial dysfunction could cause neuroinflammation and vice versa. Thus, the mitochondrial proteins are the highly promising target for the development of PD. However, the limited amount of dopaminergic neurons prevented the detailed investigation of Parkinson's disease with regard to mitochondrial dysfunction. Both genetic and environmental factors are also associated with mitochondrial dysfunction and PD pathogenesis. The induction of PD by neurotoxins that inhibit mitochondrial complex I provide direct evidence linking mitochondrial dysfunction to PD. A decrease of mitochondrial complex I activity is observed in PD brain and in neurotoxin- or genetic factor-induced in vitro and in vivo models. Moreover, PINK1, Parkin, DJ-1 and LRRK2 mitochondrial PD gene products have important roles in mitophagy, a cellular process that clear damaged mitochondria. This review paper would discuss the evidence for the mitochondrial dysfunction and neuroinflammation in PD.

B cells in multiple sclerosis - from targeted depletion to immune reconstitution therapies

Increasing evidence indicates the involvement of B cells in the pathogenesis of multiple sclerosis (MS), but their precise roles are unclear. In this Review, we provide an overview of the development and physiological functions of B cells and the main mechanisms through which B cells are thought to contribute to CNS autoimmunity. In MS, abnormalities of B cell function include pro-inflammatory cytokine production, defective B cell regulatory function and the formation of tertiary lymphoid-like structures in the CNS, which are the likely source of abnormal immunoglobulin production detectable in the cerebrospinal fluid. We also consider the hypothesis that Epstein-Barr virus (EBV) is involved in the B cell overactivation that leads to inflammatory injury to the CNS in MS. We also review the immunological effects - with a focus on the effects on B cell subsets - of several successful therapeutic approaches in MS, including agents that selectively deplete B cells (rituximab, ocrelizumab and ofatumumab), agents that less specifically deplete lymphocytes (alemtuzumab and cladribine) and autologous haematopoietic stem cell transplantation, in which the immune system is unselectively ablated and reconstituted. We consider the insights that these effects on B cell populations provide and their potential to further our understanding and targeting of B cells in MS.

Immunosuppressive Mechanisms of Regulatory B Cells

Regulatory B cells (Bregs) is a term that encompasses all B cells that act to suppress immune responses. Bregs contribute to the maintenance of tolerance, limiting ongoing immune responses and reestablishing immune homeostasis. The important role of Bregs in restraining the pathology associated with exacerbated inflammatory responses in autoimmunity and graft rejection has been consistently demonstrated, while more recent studies have suggested a role for this population in other immune-related conditions, such as infections, allergy, cancer, and chronic metabolic diseases. Initial studies identified IL-10 as the hallmark of Breg function; nevertheless, the past decade has seen the discovery of other molecules utilized by human and murine B cells to regulate immune responses. This new arsenal includes other anti-inflammatory cytokines such IL-35 and TGF-β, as well as cell surface proteins like CD1d and PD-L1. In this review, we examine the main suppressive mechanisms employed by these novel Breg populations. We also discuss recent evidence that helps to unravel previously unknown aspects of the phenotype, development, activation, and function of IL-10-producing Bregs, incorporating an overview on those questions that remain obscure.

Advances of Regulatory B Cells in Autoimmune Diseases

With the ability to induce T cell activation and elicit humoral responses, B cells are generally considered as effectors of the immune system. However, the emergence of regulatory B cells (Bregs) has given new insight into the role of B cells in immune responses. Bregs exhibit immunosuppressive functions via diverse mechanisms, including the secretion of anti-inflammatory cytokines and direct cell contact. The balance between Bregs and effector B cells is important for the immune tolerance. In this review, we focus on recent advances in the characteristics of Bregs and their functional roles in autoimmunity.

TGF-β-secreting regulatory B cells: unsung players in immune regulation

Regulatory B cells contribute to the regulation of immune responses in cancer, autoimmune disorders, allergic conditions and inflammatory diseases. Although most studies focus on regulatory B lymphocytes expressing interleukin-10, there is growing evidence that B cells producing transforming growth factor β (TGF-β) can also regulate T-cell immunity in inflammatory diseases and promote the emergence of regulatory T cells that contribute to the induction and maintenance of natural and induced immune tolerance. Most research on TGF-β⁺ regulatory B cells has been conducted in models of allergy, cancer and autoimmune diseases, but there has, as yet, been limited scrutiny of their role in the transplant setting. Herein, we review recent investigations seeking to understand how TGF-β-producing B cells direct the immune response in various inflammatory diseases and whether these regulatory cells may have a role in fostering tolerance in transplantation.

Frontiers of Autoantibodies in Autoimmune Disorders: Crosstalk Between Tfh/Tfr and Regulatory B Cells

Balance of Tfh/Tfr cell is critically important for the maintenance of immune tolerance, as evidenced by the fact that T follicular helper (Tfh) cells are central to the autoantibodies generation through providing necessary help for germinal center (GC) B cells, whereas T follicular regulatory (Tfr) cells significantly inhibit autoimmune inflammation process through restraining Tfh cell responses. However, signals underlying the regulation of Tfh and Tfr cells are largely undefined. Regulatory B cells (Bregs) is a heterogeneous subpopulation of B cells with immunosuppressive function. Considerable advances have been made in their functions to produce anti‐inflammatory cytokines and to regulate Th17, Th1, and Treg cells in autoimmune diseases. The recent identification of their correlations with dysregulated Tfr/Tfh cells and autoantibody production makes Bregs an important checkpoint in GC response. Bregs exert profound impacts on the differentiation, function, and distribution of Tfh and Tfr cells in the immune microenvironment. Thus, unraveling mechanistic information on Tfh-Breg and Tfr-Breg interactions will inspire novel implications for the establishment of homeostasis and prevention of autoantibodies in diverse diseases. This review summarizes the dysregulation of Tfh/Tfr cells in autoimmune diseases with a focus on the emerging role of Bregs in regulating the balance between Tfh and Tfr cells. The previously unsuspected crosstalk between Bregs and Tfh/Tfr cells will be beneficial to understand the cellular mechanisms of autoantibody production and evoke a revolution in immunotherapy for autoimmune diseases.

Insights into the role of B cells in the cortical pathology of Multiple sclerosis: evidence from animal models and patients

Multiple sclerosis (MS) is a chronic, immune-mediated disease of the central nervous system (CNS) that affects both white and gray matter. Although it has been traditionally considered as a T cell mediated disease, the role of B cell in MS pathology has become a topic of great research interest. Cortical lesions, key feature of the progressive forms of MS, are involved in cognitive impairment and worsening of the patients' outcome. These lesions present pathognomonic hallmarks, such as: absence of blood-brain barrier (BBB) disruption, limited inflammatory events, reactive microglia, neurodegeneration, demyelination and meningeal inflammation. B cells located in the meninges, either as part of diffuse inflammation or as part of follicle-like structures, are strongly associated with cortical damage. The function of CD20-expressing B cells in MS is further highlighted by the success of specific therapies using anti-CD20 antibodies. The possible roles of B cells in pathology go beyond their ability to produce antibodies, as they also present antigens to T cells, secrete cytokines (both pathogenic and protective) within the CNS to modulate T and myeloid cell functions, and are involved in meningeal inflammation. Here, we will review the contributions of B cells to the pathogenesis of meningeal inflammation and cortical lesions in MS patients as well as in preclinical animal models.

Detection and Quantification of Transforming Growth Factor-β1 Produced by Murine B Cells: Pros and Cons of Different Techniques

Transforming growth factor (TGF)-β1 is one of the regulatory cytokines produced by B cells and has a pivotal role in intestinal homeostasis. TGF-β1 can determine the fate of naive T cells, such as differentiation, proliferation, and apoptosis, which are relevant to the pathogenesis of autoimmunity, infection, inflammation, allergy, and cancer. Here, we describe detailed methods for detection and quantification of TGF-β1 secreted by B cells using ELISA, flow cytometry, and real-time PCR.

Medicinal Chemistry of Multiple Sclerosis: Focus on Cladribine

BACKGROUND

In the recent years, many novel Disease-Modifying Drugs (DMD) have been introduced to the market in the treatment of multiple sclerosis.

OBJECTIVES

To provide the reader with an up to date, compact review on the pharmacokinetic properties, mechanism of action, and clinical attributes of one of the most recently approved drugs in the therapy of multiple sclerosis, cladribine.

CONCLUSION

Cladribine tablets proved to be a highly efficient treatment choice for Relapsing- Remitting Multiple Sclerosis (RRMS), especially for patients with high disease activity. It is the first DMD for MS with a complex mechanism of action, by inhibiting the adenosine-deaminase enzyme it increases the intracellular levels of deoxyadenosine triphosphate, which with relative selectivity depletes both T- and B-cells lines simultaneously. However long term follow-up safety and effectiveness data are still missing, and clear treatment protocols are lacking beyond the first two treatment years cladribine should prove to be a valuable addition to the therapeutic palette of RRMS, and potentially for Clinically Isolated Syndrome (CIS) as well.

Opposing and potentially antagonistic effects of BMP and TGF-β in multiple sclerosis: The "Yin and Yang" of neuro-immune Signaling

Bone Morphogenetic Proteins (BMP) and Transforming Growth Factor-beta (TGF-β) are cytokines with similar receptors and messengers. They are important for immune cell function, with BMPs exerting mainly proinflammatory but also anti-inflammatory effects, and TGF-β suppressing inflammation. Patients with Multiple Sclerosis exhibit BMP overactivity and suppressed TGF-β signaling. This dysregulated signaling participates in the crosstalk between infiltrating immune cells and glia, where BMP inhibits remyelination. Reciprocal antagonism between the two pathways takes place via a variety of mechanisms. Although this antagonism has not been studied in the setting of Multiple Sclerosis, it could inform further research and treatment discovery.

Inhibition of Bruton's tyrosine kinase interferes with pathogenic B-cell development in inflammatory CNS demyelinating disease

Anti-CD20-mediated B-cell depletion effectively reduces acute multiple sclerosis (MS) flares. Recent data shows that antibody-mediated extinction of B cells as a lasting immune suppression, harbors the risk of developing humoral deficiencies over time. Accordingly, more selective, durable and reversible B-cell-directed MS therapies are needed. We here tested inhibition of Bruton's tyrosine kinase (BTK), an enzyme centrally involved in B-cell receptor signaling, as the most promising approach in this direction. Using mouse models of MS, we determined that evobrutinib, the first BTK inhibiting molecule being developed, dose-dependently inhibited antigen-triggered activation and maturation of B cells as well as their release of pro-inflammatory cytokines. Most importantly, evobrutinib treatment functionally impaired the capacity of B cells to act as antigen-presenting cells for the development of encephalitogenic T cells, resulting in a significantly reduced disease severity in mice. In contrast to anti-CD20, BTK inhibition silenced this key property of B cells in MS without impairing their frequency or functional integrity. In conjunction with a recent phase II trial reporting that evobrutinib is safe and effective in MS, our mechanistic data highlight therapeutic BTK inhibition as a landmark towards selectively interfering with MS-driving B-cell properties.

B cells reappear less mature and more activated after their anti-CD20-mediated depletion in multiple sclerosis

Anti-CD20–mediated B cell depletion is a highly effective therapy in MS. However, long-term effects of this approach on the immune system are not yet characterized in detail. After cessation of anti-CD20 treatment, B cells reappear immature yet highly activated. In addition, anti-CD20 treatment exerts long-lasting effects on T cells, which may be important for its clinical effect. These findings may help in guiding therapeutic decisions with regard to treatment intervals and follow-up therapies.

B cell depletion via anti-CD20 antibodies is a highly effective treatment for multiple sclerosis (MS). However, little is known about the maturation/activation stage of the returning B cell population after treatment cessation and the wider effects on other immune cells. In the present study, 15 relapsing-remitting MS patients receiving 1,000 mg of rituximab were included. B, T, and myeloid cells were analyzed before anti-CD20 administration and in different time intervals thereafter over a period of 24 mo. In comparison to the phenotype before anti-CD20 treatment, the reappearing B cell pool revealed a less mature and more activated phenotype: 1) reappearing B cells were significantly enriched in transitional (before: 10.1 ± 1.9%, after: 58.8 ± 5.2%) and mature naive phenotypes (before: 45.5 ± 3.1%, after: 25.1 ± 3.5%); 2) the frequency of memory B cells was reduced (before: 36.7 ± 3.1%, after: 8.9 ± 1.7%); and 3) reappearing B cells showed an enhanced expression of activation markers CD25 (before: 2.1 ± 0.4%, after: 9.3 ± 2.1%) and CD69 (before: 5.9 ± 1.0%, after: 21.4 ± 3.0%), and expressed significantly higher levels of costimulatory CD40 and CD86. T cells showed 1) a persistent increase in naive (CD4⁺: before: 11.8 ± 1.3%, after: 18.4 ± 3.4%; CD8⁺: before: 12.5 ± 1.4%, after: 16.5 ± 2.3%) and 2) a decrease in terminally differentiated subsets (CD4⁺: before: 47.3 ± 3.2%, after: 34.4 ± 3.7%; CD8⁺: before: 53.7 ± 2.1%, after: 49.1 ± 2.7%).

CD8+ T Cell Immunity Is Compromised by Anti-CD20 Treatment and Rescued by Interleukin-17A

Monoclonal antibody targeting the CD20 antigen on B cells is used to treat the majority of non-Hodgkin lymphoma patients and some autoimmune disorders. This therapy generates adverse effects, notably opportunistic infections and activation of viruses from latency. Here, using the infection murine model with the intracellular parasite Trypanosoma cruzi, we report that anti-CD20 treatment affects not only B cell responses but also CD8⁺ T cell responses, representing the most important immune effectors involved in control of intracellular pathogens. Anti-CD20 treatment, directly or indirectly, affects cytotoxic T cell number and function, and this deficient response was rescued by the cytokine IL-17A. The identification of IL-17A as the cytokine capable of reversing the poor response of CD8⁺ T cells provides information about a potential therapeutic treatment aimed at enhancing defective immunity induced by B cell depletion.

Treatment with anti-CD20, used in many diseases in which B cells play a pathogenic role, has been associated with susceptibility to intracellular infections. Here, we studied the effect of anti-CD20 injection on CD8⁺ T cell immunity using an experimental model of Trypanosoma cruzi infection, in which CD8⁺ T cells play a pivotal role. C57BL/6 mice were treated with anti-CD20 for B cell depletion prior to T. cruzi infection. Infected anti-CD20-treated mice exhibited a CD8⁺ T cell response with a conserved expansion phase followed by an early contraction, resulting in a strong reduction in total and parasite-specific CD8⁺ T cell numbers at 20 days postinfection. Anti-CD20 injection increased the frequency of apoptotic CD8⁺ T cells, decreased the number of effector and memory CD8⁺ T cells, and reduced the frequency of proliferating and cytokine-producing CD8⁺ T cells. Accordingly, infected anti-CD20-treated mice presented lower cytotoxicity of T. cruzi peptide-pulsed target cells in vivo. All of these alterations in CD8⁺ T cell immunity were associated with increased tissue parasitism. Anti-CD20 injection also dampened the CD8⁺ T cell response, when this had already been generated, indicating that B cells were involved in the maintenance rather than the induction of CD8⁺ T cell immunity. Anti-CD20 injection also resulted in a marked reduction in the frequency of interleukin-6 (IL-6)- and IL-17A-producing cells, and recombinant IL-17A (rIL-17A) injection partially restored the CD8⁺ T cell response in infected anti-CD20-treated mice. Thus, anti-CD20 reduced CD8⁺ T cell immunity, and IL-17A is a candidate for rescuing deficient responses either directly or indirectly.

The role of B cells in the immunopathogenesis of multiple sclerosis

There is ongoing debate on how B cells contribute to the pathogenesis of multiple sclerosis (MS). The success of B-cell targeting therapies in MS highlighted the role of B cells, particularly the antibody-independent functions of these cells such as antigen presentation to T cells and modulation of the function of T cells and myeloid cells by secreting pathogenic and/or protective cytokines in the central nervous system. Here, we discuss the role of different antibody-dependent and antibody-independent functions of B cells in MS disease activity and progression proposing new therapeutic strategies for the optimization of B-cell targeting treatments.

Biological characteristics of transcription factor RelB in different immune cell types: implications for the treatment of multiple sclerosis

Transcription factor RelB is a member of the nuclear factror-kappa B (NF-κB) family, which plays a crucial role in mediating immune responses. Plenty of studies have demonstrated that RelB actively contributes to lymphoid organ development, dendritic cells maturation and function and T cells differentiation, as well as B cell development and survival. RelB deficiency may cause a variety of immunological disorders in both mice and humans. Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system which involves a board of immune cell populations. Thereby, RelB may exert an impact on MS by modulating the functions of dendritic cells and the differentiation of T cells and B cells. Despite intensive research, the role of RelB in MS and its animal model, experimental autoimmune encephalomyelitis, is still unclear. Herein, we give an overview of the biological characters of RelB, summarize the updated knowledge regarding the role of RelB in different cell types that contribute to MS pathogenesis and discuss the potential RelB-targeted therapeutic implications for MS.

Resolution of inflammation during multiple sclerosis

Multiple sclerosis (MS) is a frequent autoimmune demyelinating disease of the central nervous system (CNS). There are three clinical forms described: relapsing-remitting multiple sclerosis (RRMS), the most common initial presentation (85%) among which, if not treated, about half will transform, into the secondary progressive multiple sclerosis (SPMS) and the primary progressive MS (PPMS) (15%) that is directly progressive without superimposed clinical relapses. Inflammation is present in all subsets of MS. The relapsing/remitting form could represent itself a particular interest for the study of inflammation resolution even though it remains incomplete in MS. Successful resolution of acute inflammation is a highly regulated process and dependent on mechanisms engaged early in the inflammatory response that are scarcely studied in MS. Moreover, recent classes of disease-modifying treatment (DMTs) that are effective against RRMS act by re-establishing the inflammatory imbalance, taking advantage of the pre-existing endogenous suppressor. In this review, we will discuss the active role of regulatory immune cells in inflammation resolution as well as the role of tissue and non-hematopoietic cells as contributors to inflammation resolution. Finally, we will explore how DMTs, more specifically induction therapies, impact the resolution of inflammation during MS.

Efficacy of Cell-Based Therapies for Traumatic Brain Injuries

Traumatic brain injuries (TBIs) are a leading cause of death and disability. Additionally, growing evidence suggests a link between TBI-induced neuroinflammation and neurodegenerative disorders. Treatments for TBI patients are limited, largely focused on rehabilitation therapy, and ultimately, fail to provide long-term neuroprotective or neurorestorative benefits. Because of the prevalence of TBI and lack of viable treatments, new therapies are needed which can promote neurological recovery. Cell-based treatments are a promising avenue because of their potential to provide multiple therapeutic benefits. Cell-based therapies can promote neuroprotection via modulation of inflammation and promote neurorestoration via induction of angiogenesis and neurogenesis. Neural stem/progenitor cell transplantations have been investigated in preclinical TBI models for their ability to directly contribute to neuroregeneration, form neural-like cells, and improve recovery. Mesenchymal stem cells (MSCs) have been investigated in clinical trials through multiple different routes of administration. Intravenous administration of MSCs appears most promising, demonstrating a robust safety profile, correlation with neurological improvements, and reductions in systemic inflammation following TBI. While still preliminary, evidence suggests cell-based therapies may become a viable treatment for TBI based on their ability to promote neuroregeneration and reduce inflammation.

A Brief Review about the Role of Nanomaterials, Mineral-Organic Nanoparticles, and Extra-Bone Calcification in Promoting Carcinogenesis and Tumor Progression

People come in contact with a huge number of nanoparticles (NPs) throughout their lives, which can be of both natural and anthropogenic origin and are capable of entering the body through swallowing, skin penetration, or inhalation. In connection with the expanding use of nanomaterials in various industrial processes, the question of whether there is a need to study the potentially adverse effects of NPs on human health becomes increasingly important. Despite the fact that the nature and the extent of damage caused depends on the chemical and the physical characteristics of individual NPs, there are also general mechanisms related to their toxicity. These mechanisms include the ability of NPs to translocate to various organs through endocytosis, as well as their ability to stimulate the production of reactive oxygen species (ROS), leading to oxidative stress, inflammation, genotoxicity, metabolic changes, and potentially carcinogenesis. In this review, we discuss the main characteristics of NPs and the effects they cause at both cellular and tissue levels. We also focus on possible mechanisms that underlie the relationship of NPs with carcinogenesis. We briefly summarize the main concepts related to the role of endogenous mineral organic NPs in the development of various human diseases and their participation in extra-bone calcification. Considering data from both our studies and those published in scientific literature, we propose the revision of some ideas concerning extra-bone calcification, since it may be one of the factors associated with the initiation of the mechanisms of immunological tolerance.

Self-reactive B cells in the GALT are actively curtailed to prevent gut inflammation

Immune homeostasis in the gut associated lymphoid tissues (GALT) is critical to prevent the development of inadvertent pathologies. B cells as the producers of antibodies and cytokines plays an important role in maintaining the GALT homeostasis. However, the mechanism by which B cells specifically direct their responses towards non-self-antigens and become ignorant to self-antigens in the GALT is not known. Therefore, we developed a novel mouse model by expressing Duck Egg Lysozyme (DEL) in gut epithelial cells in presence of HEL reactive B cells. Notably, we observed a transient activation and rapid deletion of self-reactive B cells in Peyers Patches and Mesenteric lymph nodes upon self-antigen exposure. The survival of self-reactive B cells upon exposure to their self-antigen was partially rescued by blocking receptor editing but could be completely rescued by stronger survival signal like ectopic expression of BCL2. Importantly, rescuing the self-reactive B cells promoted production of auto-antibodies and gut inflammation. Mechanistically, we identify a specific activation of TGFβ signaling in self-reactive B cells in the gut and a critical role of this pathway in maintaining peripheral tolerance. Collectively, our studies describe functional consequences and fate of self-reactive B cells in GALT and provide novel mechanistic insights governing self-tolerance of B cells in the gut.

Clinical and cytokine profile of adult acute necrotizing encephalopathy

Background

Acute necrotizing encephalopathy (ANE), a fulminant encephalopathy, is often found in childhood. It is still uncertain whether adult patients with ANE display clinical features different from patients with typical pediatric onset. Furthermore, alterations in neuroinflammatory factors in patients with ANE have not been well-characterized. Here, we present an adult patient with ANE, and review all reported adult ANE cases in the literature.

Methods

Serum levels of five cytokines were checked in an adult patient with ANE and compared with gender/age-matched controls. Literature search was performed with PubMed, using the term as “acute necrotizing encephalopathy” with the filter of adult 19 + years.

Results

A total of 13 adult patients were reviewed. Compared with pediatric patients, adult ANE patients had similar clinical symptoms, biochemical data, and neuroimage findings, whereas adult ANE were more female-biased (female:male, 9:4) with a worse prognosis. Elevated cytokine levels in the serum and/or CSF is found in both adult-onset and pediatric-onset ANE. We found significantly elevated serum levels of IL-6 (17.17 pg/mL; healthy control: 1.43 ± 1.22 pg/mL) and VCAM-1 (3033.92 ng/mL; healthy control: 589.71 ± 133.13 ng/mL), and decreased serum TGF-β1 level (14.78 ng/mL, healthy controls: 25.81 ± 6.97 ng/mL) in our patient.

Conclusions

Our findings clearly delineate the clinical features and further indicate the potential change in cytokine levels in adult patients with ANE, advancing our understanding of this rare disease.

B Cell-based Therapies for Multiple Sclerosis

The traditional view of multiple sclerosis (MS) as a T cell mediated autoimmune disease of the central nervous system (CNS) has evolved into a concept of an immune-mediated disease where complex bi-directional interactions between T cells, B cells and myeloid cells underlie and shape CNS-directed autoimmunity. B cells are now recognized as major contributors to the pathogenesis of MS, largely due to increased understanding of their biology and the profound anti-inflammatory effects demonstrated by B cell depletion in MS. In this chapter we discuss the fundamental roles B cells play in the pathogenesis of MS and review current and future therapeutic strategies targeting B cells in MS, including B cell depletion with various monoclonal antibodies (mAbs) against the B cell surface markers CD20 and CD19, anti-B cell cytokine therapies, blocking Bruton's tyrosine kinase (BTK) in B cells, and various immunomodulatory and immunosuppressive effects exerted on B cells by virtually all other approved therapies for MS.

Intraparenchymal Application of Mature B Lymphocytes Improves Structural and Functional Outcome after Contusion Traumatic Brain Injury

Cerebral contusion causes neurological dysfunction mediated in part by inflammatory responses to injury. B lymphocytes are dynamic regulators of the immune system that have not been systematically studied in traumatic brain injury (TBI). We showed previously that topically applied mature B cells have immunomodulatory properties and strongly promote tissue regeneration, including cutaneous nerve growth, in acute and chronic skin wounds. Using a mouse controlled cortical impact (CCI) model, we assessed a possible beneficial role of exogenously applied B cells on histopathological and functional outcome after TBI. Mice were injected intraparenchymally at the lesion site with 2 × 10⁶ mature naïve syngeneic splenic B cells, then subjected to CCI. Control CCI mice received equal numbers of T cells or saline, and sham-injured mice (craniotomy only) were given B cells or saline. Sham-injured groups performed similarly in motor and learning tests. Injured mice administered B cells showed significantly improved post-injury rotarod, Y maze, and Morris water maze (MWM) performance compared with saline- or T-cell-treated CCI groups. Moreover, lesion volume in mice treated with B cells was significantly reduced by 40% at 35 days post-TBI compared with saline and T cell controls, and astrogliosis and microglial activation were decreased. In vivo tracking of exogenous B cells showed that they have a limited life span of approximately 14 days in situ and do not appear to proliferate. The data suggest proof of principle that local administration of B lymphocytes may represent a therapeutic option for treatment of cerebral contusion, especially when clinical management involves procedures that allow access to the injury site.

Severe rebound after cessation of fingolimod treated with ocrelizumab with coincidental transient aggravation: report of two cases

Background

Fingolimod (FTY), an oral treatment for patients with relapsing-remitting multiple sclerosis (RRMS), has been associated with a significant rebound of disease activity after cessation of therapy.

Methods

We present the clinical and radiological findings of two patients with severe rebound after FTY withdrawal, which was further aggravated by the initiation of treatment with the B cell-depleting monoclonal antibody, ocrelizumab.

Results

Both patients exhibited significant Expanded Disability Status Scale progression after administration of ocrelizumab despite immune reconstitution more than 3 months after FTY withdrawal.

Conclusions

Although the observed effect may be coincidental, ocrelizumab may complicate recovery of rebound after cessation of FTY. Further studies are warranted to better understand and predict the clinical and immunological consequences of sequential immunosuppressive and immunomodulatory treatments in patients with highly active RRMS.

The Multiple Roles of B Cells in Multiple Sclerosis and Their Implications in Multiple Sclerosis Therapies

Increasing evidence has suggested that both antibody-dependent and antibody-independent functions of B cells are involved in multiple sclerosis (MS). The contrasting results of distinct B-cell targeting therapies in MS patients underscores the importance of elucidating these multiple B-cell functions. In this review, we discuss the generation of autoreactive B cells, migration of B cells into the central nervous system (CNS), and how different functions of B cells may contribute to MS disease activity and potentially mitigation in both the periphery and CNS compartments. In addition, we propose several future therapeutic strategies that may better target/shape B-cell responses for long-term treatment of MS.

Calcium Carbonate Nanoparticles Can Activate the Epithelial⁻Mesenchymal Transition in an Experimental Gastric Cancer Model

Previously, we have shown the possibility of intramucosal gastric carcinoma induction by the intragastric administration of a mixture of formaldehyde and hydrogen peroxide in rats. In this study, we report a sizable increase in carcinogenic properties of the mixture when a suspension containing calcium carbonate nanoparticles was added to it. This technique allowed us to reduce both the number of the carcinogen administrations from twelve to two and the time to the cancer induction from six to four months. Although the induced tumors were represented by the intramucosal carcinomas, they were characterized by the extensive invasion of individual tumor cells and their clusters into the muscle layer and serosa as well as into the omentum and blood vessels. Considering that the invasive tumor cells were positive for vimentin, Snail and TGF-β2, we concluded that their invasion was the result of the activation of epithelial⁻mesenchymal transition (EMT) mechanisms. Thus, taking into account the data obtained, it can be assumed that under the conditions of inflammation or carcinogenesis, the calcium carbonate nanoparticles may affect the activation of EMT mechanisms.

The Role of B Cells and Antibodies in Multiple Sclerosis, Neuromyelitis Optica, and Related Disorders

Our pathophysiological concept of the most common central nervous system demyelinating disease, multiple sclerosis, strikingly evolved by recent discoveries suggesting that B lymphocytes substantially contribute in its initiation and chronic propagation. In this regard, activated B cells are nowadays considered to act as important antigen-presenting cells for the activation of T cells and as essential source of pro-inflammatory cytokines. Hereby, they create a milieu in which other immune cells differentiate and join an orchestrated inflammatory infiltration of the CNS. Without a doubt, this scientific leap was critically pioneered by the empirical use of anti-CD20 antibodies in recent clinical MS trials, which revealed that the therapeutic removal of immature and mature B cells basically halted development of new inflammatory flares in otherwise relapsing MS patients. This stabilization occurred largely independent of any indirect effect on plasma cell-produced antibody levels. On the contrary, peripherally produced autoantibodies are probably the most important B cell component in two other CNS demyelinating diseases which are currently in the process of being delineated as separate disease entities. The first one is neuromyelitis optica in which an antibody response against aquaporin-4 targets and destroys astrocytes, the second, likely distinct entity embraces a group of patients containing antibodies against myelin oligodendrocyte glycoprotein. In this review, we will describe and summarize pro-inflammatory B cell properties in these three CNS demyelinating disorders; we will however also provide an overview on the emerging concept that B cells or B cell subsets may exert immunologically counterbalancing properties, which may be therapeutically desirable to maintain and foster in inflammatory CNS demyelination. In an outlook, we will discuss accordingly, how this potentially important aspect can be harnessed to advance future B cell-directed therapeutic approaches in multiple sclerosis and related diseases.

TGFβ Superfamily Members as Regulators of B Cell Development and Function-Implications for Autoimmunity

The TGFβ superfamily is composed of more than 33 growth and differentiation factors, including TGFβ1, β2, β3, BMPs, GDFs, nodal-related proteins, and activins. These members usually exert pleiotropic actions on several tissues and control multiple cellular processes, such as cell growth, cell survival, cell migration, cell fate specification, and differentiation, both during embryonic development and postnatal life. Although the effects of these factors on immune responses were elucidated long ago, most studies have been focused on the actions of TGFβs on T cells, as major regulators of adaptive immunity. In this review, we discuss new findings about the involvement of TGFβ superfamily members in the control of B cell development and function. Moreover, the potential contribution of TGFβ signaling to control B cell-mediated autoimmune diseases and its utility in the design of new therapies are also discussed.

Regulatory B and T lymphocytes in multiple sclerosis: friends or foes?

Current clinical experience with immunomodulatory agents and monoclonal antibodies in principle has established the benefit of depleting lymphocytic populations in relapsing–remitting multiple sclerosis (RRMS). B and T cells may exert multiple pro-inflammatory actions, but also possess regulatory functions making their role in RRMS pathogenesis much more complex. There is no clear correlation of Tregs and Bregs with clinical features of the disease. Herein, we discuss the emerging data on regulatory T and B cell subset distributions in MS and their roles in the pathophysiology of MS and its murine model, experimental autoimmune encephalomyelitis (EAE). In addition, we summarize the immunomodulatory properties of certain MS therapeutic agents through their effect on such regulatory cell subsets and their relevance to clinical outcomes.