Dimethyl fumarate: Regulatory effects on the immune system in the treatment of multiple sclerosis

Immunotherapy-mediated modulation of the gut microbiota in multiple sclerosis and associations with diet and clinical response-the effect of dimethyl fumarate therapy

Background

Accumulating evidence supports a role of the microbiota in health and disease, including in multiple sclerosis (MS). How MS drugs affect the microbiota and whether this is part of their mode of action is yet unknown.

Objectives

To assess how dimethyl fumarate (DMF) affects the gut microbiota and whether the microbiota is associated with clinical response or adverse events (AEs) to DMF or diet.

Design

An observational cohort study, in which the microbiota from 45 patients with relapsing-remitting MS pre-DMF initiation and following 6 months of DMF therapy, and from 47 matched healthy controls, were compared, and associations with clinical and dietary data assessed.

Data sources and methods

Microbial DNA was sequenced and analyzed using MicrobiomeAnalyst. The clinical response was assessed after 1-year DMF therapy based upon evidence of disease activity (relapse, ΔEDSS increase >1, or MRI activity compared to pre-treatment). Dietary data were obtained by food questionnaires.

Results

Alterations in relative abundance of several microbes were identified post 6-month DMF therapy compared to pre-treatment, including an increase in Firmicutes, Lachnospiraceae, and Ruminococcaceae, while reduction in Bacteroidetes and Proteobacteria. Patients who showed disease activity within 1 year from DMF initiation had pre-treatment higher abundance of Proteobacteria, Flavonifractor, and Acidaminococcaceae, while lower abundance of Firmicutes, Ruminococcaceae, Butyricicoccus, and Massiliprevotella massiliensis, compared to patients without disease activity. Patients who discontinued DMF therapy due to AEs had pre-treatment higher abundance of Proteobacteria, Bacteroidetes, Eggerthella, and Lachnoclostridium and lower abundance of Ruminococcaceae, Megamonas, and Holdemanella, among others. Differentially abundant microbes correlated with intake of several nutrients.

Conclusion

DMF immunotherapy is associated with modifications of the microbiota. The microbiota may affect the severity of AEs and the clinical response to DMF, and is potentially modulated by diet. Microbiota-based, personalized treatment approach, integrating pharmacotherapy with dietary components, carries potential to improved clinical outcome.

Current and Evolving Concepts in the Management of Complex Regional Pain Syndrome: A Narrative Review

Background/Objectives: Complex regional pain syndrome (CRPS) is characterized by severe pain and reduced functionality, which can significantly affect an individual's quality of life. The current treatment of CRPS is challenging. However, recent advances in diagnostic and treatment methods show promise for improving patient outcomes. This review aims to place the question of CRPS in a broader context and highlight the objectives of the research for future directions in the management of CRPS. Methods: This study involved a comprehensive literature review. Results: Research has identified three primary pathophysiological pathways that may explain the clinical variability observed in CRPS: inflammatory mechanisms, vasomotor dysfunction, and maladaptive neuroplasticity. Investigations into these pathways have spurred the development of novel diagnostic and treatment strategies focused on N-Methyl-D-aspartate Receptor Antagonists (NMDA), Toll-like receptor 4 (TLR-4), α1 and α2 adrenoreceptors, as well as the identification of microRNA (miRNA) biomarkers. Treatment methods being explored include immune and glial-modulating agents, intravenous immunoglobulin (IVIG) therapy, plasma exchange therapy, and neuromodulation techniques. Additionally, there is ongoing debate regarding the efficacy of other treatments, such as free radical scavengers, alpha-lipoic acid (ALA), dimethyl fumarate (DMF), adenosine monophosphate-activated protein kinase (AMPK) activators such as metformin, and phosphodiesterase-5 inhibitors such as tadalafil. Conclusions: The controversies surrounding the mechanisms, diagnosis, and treatment of CRPS have prompted researchers to investigate new approaches aimed at enhancing understanding and management of the condition, with the goal of alleviating symptoms and reducing associated disabilities.

Chemokines in neurodegenerative diseases

Neurodegeneration and neuroinflammation disorders are mainly the result of the deposition of various proteins, such as α-synuclein, amyloid-β and prions, which lead to the initiation and activation of inflammatory responses. Different chemokines are involved in the infiltration and movement of inflammatory leukocytes into the central nervous system (CNS) that express chemokine receptors. Dysregulation of several members of chemokines has been shown in the CNS, cerebrospinal fluid and peripheral blood of patients who have neurodegenerative disorders. Upon infiltration of various cells, they produce many inflammatory mediators such as cytokines. Besides them, some CNS-resident cells, such as neurons and astrocytes, are also involved in the pathogenesis of neurodegeneration by producing chemokines. In this review, we summarize the role of chemokines and their related receptors in the pathogenesis of neurodegeneration and neuroinflammation disorders, including multiple sclerosis, Parkinson's disease and Alzheimer's disease. Therapeutic strategies targeting chemokines or their related receptors are also discussed in this article.

Understanding Multiple Sclerosis Pathophysiology and Current Disease-Modifying Therapies: A Review of Unaddressed Aspects

Multiple sclerosis (MS) is a complex autoimmune disorder of the central nervous system (CNS) with an unknown etiology and pathophysiology that is not completely understood. Although great strides have been made in developing disease-modifying therapies (DMTs) that have significantly improved the quality of life for MS patients, these treatments do not entirely prevent disease progression or relapse. Identifying the unaddressed pathophysiological aspects of MS and developing targeted therapies to fill in these gaps are essential in providing long-term relief for patients. Recent research has uncovered some aspects of MS that remain outside the scope of available DMTs, and as such, yield only limited benefits. Despite most MS pathophysiology being targeted by DMTs, many patients still experience disease progression or relapse, indicating that a more detailed understanding is necessary. Thus, this literature review seeks to explore the known aspects of MS pathophysiology, identify the gaps in present DMTs, and explain why current treatments cannot entirely arrest MS progression.

Simvastatin alleviates experimental autoimmune encephalomyelitis through regulating the balance of Th17 and Treg in mice

The aim of this study was to elucidate the therapeutic effect of simvastatin on experimental autoimmune encephalomyelitis (EAE) by regulating the balance between Th17 and Treg cells in mice. C57BL/6 mice were randomly divided into four groups: normal group, EAE group, simvastatin (2 and 10 mg/kg) group, and AG490 group (with AG490 serving as the positive control). Neurological function scores of mice were assessed daily. The four groups received treatments of normal saline, normal saline, and simvastatin (2 and 10 mg/kg), respectively. In the AG490 group, mice were injected intraperitoneally with AG490 (1 mg) every other day, and treatment was halted after 3 weeks. The spinal cord was stained with hematoxylin and eosin (H&E), and immunohistochemical staining for retinoic acid receptor-related orphan receptor γ(RORγ) and Foxp3 (Foxp3) was performed. Spleen samples were taken for Th17 and Treg analysis using flow cytometry. The levels of interleukin-17 and transforming growth factor-β (TGF-β) were detected using enzyme-linked immunosorbent assay (ELISA). In the simvastatin and AG490 groups, recovery from neurological impairment was earlier compared to the EAE group, and the symptoms were notably improved. Both simvastatin and AG490 reduced focal inflammation, decreased RORγ-positive cell infiltration, and significantly increased the number of FOXP3-positive cells. The number of Th17 cells and the level of IL-17 in the spleen were decreased in the simvastatin and AG490 treatment groups, while the number of Treg cells and TGF-β levels were significantly increased across all treatment groups. Simvastatin exhibits anti-inflammatory and immunomodulatory effects, potentially alleviating symptoms of neurological dysfunction of EAE. Regulating the balance between Th17 and Treg may represent a therapeutic mechanism for simvastatin in treating EAE.

Remodeling of the Intra-Conduit Inflammatory Microenvironment to Improve Peripheral Nerve Regeneration with a Neuromechanical Matching Protein-Based Conduit

Peripheral nerve injury (PNI) remains a challenging area in regenerative medicine. Nerve guide conduit (NGC) transplantation is a common treatment for PNI, but the prognosis of NGC treatment is unsatisfactory due to 1) neuromechanical unmatching and 2) the intra-conduit inflammatory microenvironment (IME) resulting from Schwann cell pyroptosis and inflammatory-polarized macrophages. A neuromechanically matched NGC composed of regenerated silk fibroin (RSF) loaded with poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (P:P) and dimethyl fumarate (DMF) are designed, which exhibits a matched elastic modulus (25.1 ± 3.5 MPa) for the peripheral nerve and the highest 80% elongation at break, better than most protein-based conduits. Moreover, the NGC can gradually regulate the intra-conduit IME by releasing DMF and monitoring sciatic nerve movements via piezoresistive sensing. The combination of NGC and electrical stimulation modulates the IME to support PNI regeneration by synergistically inhibiting Schwann cell pyroptosis and reducing inflammatory factor release, shifting macrophage polarization from the inflammatory M1 phenotype to the tissue regenerative M2 phenotype and resulting in functional recovery of neurons. In a rat sciatic nerve crush model, NGC promoted remyelination and functional and structural regeneration. Generally, the DMF/RSF/P:P conduit provides a new potential therapeutic approach to promote nerve repair in future clinical treatments.

Dimethyl fumarate restores Ca2+ dyshomeostasis through activation of the SIRT1 signal to treat nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by an excessive lipid accumulation in the liver, with a global prevalence of approximately 25 %. While early-stage steatosis is reversible and can be intervened upon, it has the potential to progress to some serious complications, including cirrhosis and even liver cancer. Dimethyl fumarate (DMF), a derivative of fumaric acid shows promise in intervening in certain diseases. However, the precise effect and underlying mechanism of DMF on hepatic steatosis remain unclear. In this study, we demonstrated that DMF mitigates hepatic steatosis in mice subjected to high-fat/high-cholesterol (HFHC) diets. Meanwhile, our in vivo and in vitro results showed that DMF relieves lipid accumulation, oxidative stress, and endoplasmic reticulum (ER) stress. Mechanically, our findings revealed that the effect of DMF on reducing lipid accumulation is linked to the restoration of Ca2+ homeostasis. Furthermore, we found that activation of the SIRT1 signal by DMF plays an important role in correcting the mishandling of the Ca2+ signal, and knockdown of SIRT1 expression reverses the beneficial role of DMF PA-incubated AML12 cells. In conclusion, our results suggested DMF's amelioration of hepatic steatosis is related to the activation of SIRT1-mediated Ca2+ signaling.

Dimethyl Fumarate and Intestine: From Main Suspect to Potential Ally against Gut Disorders

Dimethyl fumarate (DMF) is a well-characterized molecule that exhibits immuno-modulatory, anti-inflammatory, and antioxidant properties and that is currently approved for the treatment of psoriasis and multiple sclerosis. Due to its Nrf2-dependent and independent mechanisms of action, DMF has a therapeutic potential much broader than expected. In this comprehensive review, we discuss the state-of-the-art and future perspectives regarding the potential repurposing of DMF in the context of chronic inflammatory diseases of the intestine, such as inflammatory bowel disorders (i.e., Crohn's disease and ulcerative colitis) and celiac disease. DMF's mechanisms of action, as well as an exhaustive analysis of the in vitro/in vivo evidence of its beneficial effects on the intestine and the gut microbiota, together with observational studies on multiple sclerosis patients, are here reported. Based on the collected evidence, we highlight the new potential applications of this molecule in the context of inflammatory and immune-mediated intestinal diseases.

Monomethyl fumarate prevents alloimmune rejection in mouse heart transplantation by inducing tolerogenic dendritic cells

Dendritic cells (DCs) are important targets for eliciting allograft rejection after transplantation. Previous studies have demonstrated that metabolic reprogramming of DCs can transform their immune functions and induce their differentiation into tolerogenic DCs. In this study, we aim to investigate the protective effects and mechanisms of monomethyl fumarate (MMF), a bioactive metabolite of fumaric acid esters, in a mouse model of allogeneic heart transplantation. Bone marrow-derived DCs are harvested and treated with MMF to determine the impact of MMF on the phenotype and immunosuppressive function of DCs by flow cytometry and T-cell proliferation assays. RNA sequencing and Seahorse analyses are performed for mature DCs and MMF-treated DCs (MMF-DCs) to investigate the underlying mechanism. Our results show that MMF prolongs the survival time of heart grafts and inhibits the activation of DCs in vivo. MMF-DCs exhibit a tolerogenic phenotype and function in vitro. RNA sequencing and Seahorse analyses reveal that MMF activates the Nrf2 pathway and mediates metabolic reprogramming. Additionally, MMF-DC infusion prolongs cardiac allograft survival, induces regulatory T cells, and inhibits T-cell activation. MMF prevents allograft rejection in mouse heart transplantation by inducing tolerogenic DCs.

Repurposing MS immunotherapies for CIDP and other autoimmune neuropathies: unfulfilled promise or efficient strategy?

Despite advances in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and other common autoimmune neuropathies (AN), still-many patients with these diseases do not respond satisfactorily to the available treatments. Repurposing of disease-modifying therapies (DMTs) from other autoimmune conditions, particularly multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), is a promising strategy that may accelerate the establishment of novel treatment choices for AN. This approach appears attractive due to homologies in the pathogenesis of these diseases and the extensive post-marketing experience that has been gathered from treating MS and NMOSD patients. The idea is also strengthened by a number of studies that explored the efficacy of DMTs in animal models of AN but also in some CIDP patients. We here review the available preclinical and clinical data of approved MS therapeutics in terms of their applicability to AN, especially CIDP. Promising therapeutic approaches appear to be B cell-directed and complement-targeting strategies, such as anti-CD20/anti-CD19 agents, Bruton's tyrosine kinase inhibitors and anti-C5 agents, as they exert their effects in the periphery. This is a major advantage because, in contrast to MS, their action in the periphery is sufficient to exert significant immunomodulation.

The role of angiogenesis in melanoma: Clinical treatments and future expectations

The incidence of melanoma has increased rapidly over the past few decades, with mortality accounting for more than 75% of all skin cancers. The high metastatic potential of Melanoma is an essential factor in its high mortality. Vascular angiogenic system has been proved to be crucial for the metastasis of melanoma. An in-depth understanding of angiogenesis will be of great benefit to melanoma treatment and may promote the development of melanoma therapies. This review summarizes the recent advances and challenges of anti-angiogenic agents, including monoclonal antibodies, tyrosine kinase inhibitors, human recombinant Endostatin, and traditional Chinese herbal medicine. We hope to provide a better understanding of the mechanisms, clinical research progress, and future research directions of melanoma.

Evaluation of Selected Oxidant/Antioxidant Parameters in Patients with Relapsing-Remitting Multiple Sclerosis Undergoing Disease-Modifying Therapies

The aim of this study was to evaluate oxidative stress parameters, specifically the concentration of advanced oxidation protein products (AOPP) and ferric-reducing antioxidant power (FRAP), in the serum of patients with relapsing-remitting multiple sclerosis (RRMS). We also analyzed the relationships between each parameter and selected clinical/laboratory multiple-sclerosis-related parameters. The study group comprised 204 patients with RRMS and 29 healthy, age-matched controls. The concentration of AOPP was significantly higher in the RRMS patients than in controls. ROC analysis showed the ability of AOPP to distinguish between the patients with RRMS and controls (the value of AUC was 94.8%, with a sensitivity of 89.69% and specificity of 89.3%). AOPP and FRAP were significantly higher in male than in female RRMS patients. Correlations were found between AOPP and the laboratory markers of inflammation. AOPP differed in the subgroups of patients treated with particular medications. Our findings indicate an increase in the markers of oxidative stress in the serum of RRMS patients, possibly linked with chronic inflammation. Gender and type of treatment affected the markers of oxidative stress.

Autoreactive lymphocytes in multiple sclerosis: Pathogenesis and treatment target

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by destruction of the myelin sheath structure. The loss of myelin leads to damage of a neuron’s axon and cell body, which is identified as brain lesions on magnetic resonance image (MRI). The pathogenesis of MS remains largely unknown. However, immune mechanisms, especially those linked to the aberrant lymphocyte activity, are mainly responsible for neuronal damage. Th1 and Th17 populations of lymphocytes were primarily associated with MS pathogenesis. These lymphocytes are essential for differentiation of encephalitogenic CD8⁺ T cell and Th17 lymphocyte crossing the blood brain barrier and targeting myelin sheath in the CNS. B-lymphocytes could also contribute to MS pathogenesis by producing anti-myelin basic protein antibodies. In later studies, aberrant function of Treg and Th9 cells was identified as contributing to MS. This review summarizes the aberrant function and count of lymphocyte, and the contributions of these cell to the mechanisms of MS. Additionally, we have outlined the novel MS therapeutics aimed to amend the aberrant function or counts of these lymphocytes.

Anti-Oxidative Therapy in Islet Cell Transplantation

Islet cell transplantation has become a favorable therapeutic approach in the treatment of Type 1 Diabetes due to the lower surgical risks and potential complications compared to conventional pancreas transplantation. Despite significant improvements in islet cell transplantation outcomes, several limitations hamper long-term graft survival due to tremendous damage and loss of islet cells during the islet cell transplantation process. Oxidative stress has been identified as an omnipresent stressor that negatively affects both the viability and function of isolated islets. Furthermore, it has been established that at baseline, pancreatic β cells exhibit reduced antioxidative capacity, rendering them even more susceptible to oxidative stress during metabolic stress. Thus, identifying antioxidants capable of conferring protection against oxidative stressors present throughout the islet transplantation process is a valuable approach to improving the overall outcomes of islet cell transplantation. In this review we discuss the potential application of antioxidative therapy during each step of islet cell transplantation.

Dysregulation of β-Cell Proliferation in Diabetes: Possibilities of Combination Therapy in the Development of a Comprehensive Treatment

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia as a result of insufficient insulin levels and/or impaired function as a result of autoimmune destruction or insulin resistance. While Type 1 DM (T1DM) and Type 2 DM (T2DM) occur through different pathological processes, both result in β-cell destruction and/or dysfunction, which ultimately lead to insufficient β-cell mass to maintain normoglycemia. Therefore, therapeutic agents capable of inducing β-cell proliferation is crucial in treating and reversing diabetes; unfortunately, adult human β-cell proliferation has been shown to be very limited (~0.2% of β-cells/24 h) and poorly responsive to many mitogens. Furthermore, diabetogenic insults result in damage to β cells, making it ever more difficult to induce proliferation. In this review, we discuss β-cell mass/proliferation pathways dysregulated in diabetes and current therapeutic agents studied to induce β-cell proliferation. Furthermore, we discuss possible combination therapies of proliferation agents with immunosuppressants and antioxidative therapy to improve overall long-term outcomes of diabetes.

Nrf2/Keap1/ARE signaling: Towards specific regulation

The Nrf2 transcription factor governs the expression of hundreds genes involved in cell defense against oxidative stress, the hallmark of numerous diseases such as neurodegenerative, cardiovascular, some viral pathologies, diabetes and others. The main route for Nrf2 activity regulation is via interactions with the Keap1 protein. Under the normoxia the Keap1 binds the Nrf2 and targets it to the proteasomal degradation, while the Keap1 is regenerated. Upon oxidative stress the interactions between Nrf2 and Keap1 are interrupted and the Nrf2 activates the transcription of the protective genes. Currently, the Nrf2 system activation is considered as a powerful cytoprotective strategy for treatment of different pathologies, which pathogenesis relies on oxidative stress including viral diseases of pivotal importance such as COVID-19. The implementation of this strategy is accomplished mainly through the inactivation of the Keap1 "guardian" function. Two approaches are now developing: the Keap1 modification via electrophilic agents, which leads to the Nrf2 release, and direct interruption of the Nrf2:Keap1 protein-protein interactions (PPI). Because of theirs chemical structure, the Nrf2 electrophilic inducers could non-specifically interact with others cellular proteins leading to undesired effects. Whereas the non-electrophilic inhibitors of the Nrf2:Keap1 PPI could be more specific, thereby widening the therapeutic window.

Oncometabolites-A Link between Cancer Cells and Tumor Microenvironment

The tumor microenvironment is the space between healthy tissues and cancer cells, created by the extracellular matrix, blood vessels, infiltrating cells such as immune cells, and cancer-associated fibroblasts. These components constantly interact and influence each other, enabling cancer cells to survive and develop in the host organism. Accumulated intermediate metabolites favoring dysregulation and compensatory responses in the cell, called oncometabolites, provide a method of communication between cells and might also play a role in cancer growth. Here, we describe the changes in metabolic pathways that lead to accumulation of intermediate metabolites: lactate, glutamate, fumarate, and succinate in the tumor and their impact on the tumor microenvironment. These oncometabolites are not only waste products, but also link all types of cells involved in tumor survival and progression. Oncometabolites play a particularly important role in neoangiogenesis and in the infiltration of immune cells in cancer. Oncometabolites are also associated with a disrupted DNA damage response and make the tumor microenvironment more favorable for cell migration. The knowledge summarized in this article will allow for a better understanding of associations between therapeutic targets and oncometabolites, as well as the direct effects of these particles on the formation of the tumor microenvironment. In the future, targeting oncometabolites could improve treatment standards or represent a novel method for fighting cancer.

Melanoma Cell Adhesion Molecule Expressing Helper T Cells in CNS Inflammatory Demyelinating Diseases

BACKGROUND AND OBJECTIVE

To elucidate the relationship between melanoma cell adhesion molecule (MCAM)-expressing lymphocytes and pathogenesis of CNS inflammatory demyelinating diseases (IDDs).

METHODS

Patients with multiple sclerosis (MS) (n = 72) and neuromyelitis optica spectrum disorder (NMOSD, n = 29) were included. We analyzed the frequency and absolute numbers of MCAM⁺ lymphocytes (memory helper T [mTh] cells, naive helper T cells, CD8⁺ T cells, and B cells) in the peripheral blood (PB) and the CSF of patients with MS and NMOSD, treated with/without disease-modifying drugs (DMDs) or steroids, using flow cytometry.

RESULTS

The frequency of MCAM⁺ cells was higher in the mTh cell subset than that in other lymphocyte subsets. A significant increase in the frequency and the absolute number of MCAM⁺ mTh cells was observed in the PB of patients with NMOSD, whereas no increase was observed in the PB of patients with MS. The frequency of CSF MCAM⁺ mTh cells was higher in relapsing patients with MS and NMOSD than that in the control group. Although there was no difference in the frequencies of MCAM⁺ lymphocytes among the DMD-treated groups, fingolimod decreased the absolute number of MCAM⁺ lymphocytes.

DISCUSSION

MCAM⁺ mTh cells were elevated in the CSF of relapsing patients with MS and in both the PB and CSF of patients with NMOSD. These results indicate that MCAM contributes to the pathogenesis of MS and NMOSD through different mechanisms. MCAM could be a therapeutic target of CNS IDDs, and further study is needed to elucidate the underlying mechanism of MCAM in CNS IDD pathogenesis.

Targeting NRF2 to treat cancer

NRF2 is a basic leucine zipper (bZip) transcription factor that is the master regulator of redox homeostasis. Under basal conditions, the cellular level of NRF2 is low due to a posttranslational regulation by the ubiquitin proteasome system (UPS). But, when an organism is challenged with oxidative or xenobiotic stress, the NRF2 pathway is activated by inhibition of the E3 ubiquitin ligase complex that normally marks NRF2 for destruction. For several decades, researchers have searched for molecules that can intentionally activate NRF2, as this was shown to be a means to prevent certain diseases, at least in animal models. In the present era, there are many compounds known to activate the NRF2 pathway including natural products and synthetic compounds, covalent and non-covalent compounds, and others. However, it was also revealed that like many protective pathways, the NRF2 pathway has a dark side. Just as NRF2 can protect normal cells from damage, it can protect malignant cells from damage. As cells transform, they are exposed to many stressors and aberrant upregulation of NRF2 can facilitate transformation and it can help cancer cells to grow, to spread, and to resist treatment. For this reason, researchers are also interested in the discovery and development of NRF2 inhibitors. In the present review, we will begin with a general discussion of NRF2 structure and function, we will discuss the latest in NRF2 non-covalent activators, and we will discuss the current state of NRF2 inhibitors.

Drugs used in the treatment of multiple sclerosis during COVID-19 pandemic: a critical viewpoint

Since COVID-19 has emerged as a word public health problem, attention has been focused on how immune-suppressive drugs used for the treatment of autoimmune disorders influence the risk for SARS-CoV-2 infection and the development of acute respiratory distress syndrome (ARDS). Here, we discuss the disease-modifying agents approved for the treatment of multiple sclerosis (MS) within this context. Interferon (IFN)-β1a and -1b, which display antiviral activity, could be protective in the early stage of COVID-19 infection, although SARS-CoV-2 may have developed resistance to IFNs. However, in the hyperinflammation stage, IFNs may become detrimental by facilitating macrophage invasion in the lung and other organs. Glatiramer acetate and its analogues should not interfere with the development of COVID-19 and may be considered safe. Teriflunomide, a first-line oral drug used in the treatment of relapsing-remitting MS (RRMS), may display antiviral activity by depleting cellular nucleotides necessary for viral replication. The other first-line drug, dimethyl fumarate, may afford protection against SARS-CoV-2 by activating the Nrf-2 pathway and reinforcing the cellular defenses against oxidative stress. Concern has been raised regarding the use of second-line treatments for MS during the COVID-19 pandemic. However, this concern is not always justified. For example, fingolimod might be highly beneficial during the hyperinflammatory stage of COVID-19 for a number of mechanisms, including the reinforcement of the endothelial barrier. Caution is suggested for the use of natalizumab, cladribine, alemtuzumab, and ocrelizumab, although MS disease recurrence after discontinuation of these drugs may overcome a potential risk for COVID-19 infection.

Ruxolitinib attenuates experimental autoimmune encephalomyelitis (EAE) development as animal models of multiple sclerosis (MS)

AIMS

STAT3 signaling is critical for Th17 development that plays an important role in multiple sclerosis pathogenesis. To evaluate the anti-inflammatory and regulatory T cells effects of JAK1/2 and STAT3 inhibition, we assessed the JAK 1/2 inhibitor ruxolitinib effects on Th17 cell/Tregs balance.

MAIN METHODS

Ruxolitinib was administered to experimental autoimmune encephalomyelitis (EAE) mice via oral gavage, and its effects were assessed. The expression of pro-inflammatory and anti-inflammatory cytokines, including IL-17A and IL-10, were analyzed by real-time PCR. The frequency of Th17 cells and Tregs were evaluated by flow cytometry.

KEY FINDING

Ruxolitinib ameliorated the EAE severity and decreased the proportion of Th17 cells and inflammatory markers levels. In contrast, the balance of Tregs and the level of anti-inflammatory cytokine were increased in ruxolitinib-treated mice. Furthermore, ruxolitinib markedly decreased the expression of Th17 related transcription factor, RORɣt, whereas FOXP3 expression associated with Treg differentiation was increased.

SIGNIFICANCE

Our results show that ruxolitinib may be a promising therapeutic strategy for multiple sclerosis.

Dimethyl Fumarate Induces Metabolic Crisie to Suppress Pancreatic Carcinoma

Dimethyl fumarate (DMF) is an approved drug used in the treatment of multiple sclerosis (MS) and psoriasis therapy. Multiple studies have demonstrated other pharmacological activities of DMF such as an anti-cancer agent. In particular, studies have shown that DMF can modulate the NRF2/HO1/NQO1 antioxidant signal pathway and inactivate NF-κB to suppress the growth of colon and breast cancer cells, and induce cell death. In this study, we aimed to evaluate the anti-tumor activities of DMF in pancreatic cancer (PC) focusing on cell death as the predominant mechanism of response. We showed that both mitochondrial respiration and aerobic glycolysis were severely depressed following treatment with DMF and the effects could be abrogated by treatment with L-cysteine and N-acetyl-L-cysteine (NAC). Importantly, we verified that DMF induced metabolic crisis and that cell death was not related to alterations in ROS. Our data implied that MTHFD1 could be a potential downstream target of DMF identified by molecular docking analysis. Finally, we confirmed that MTHFD1 is up-regulated in PC and overexpression of MTHFD1 was negatively related to outcomes of PC patients. Our data indicate that DMF induces metabolic crisie to suppress cell growth and could be a potential novel therapy in the treatment of PC.

Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses

The tricarboxylic acid cycle (TCA) is a series of chemical reactions used in aerobic organisms to generate energy via the oxidation of acetylcoenzyme A (CoA) derived from carbohydrates, fatty acids and proteins. In the eukaryotic system, the TCA cycle occurs completely in mitochondria, while the intermediates of the TCA cycle are retained inside mitochondria due to their polarity and hydrophilicity. Under cell stress conditions, mitochondria can become disrupted and release their contents, which act as danger signals in the cytosol. Of note, the TCA cycle intermediates may also leak from dysfunctioning mitochondria and regulate cellular processes. Increasing evidence shows that the metabolites of the TCA cycle are substantially involved in the regulation of immune responses. In this review, we aimed to provide a comprehensive systematic overview of the molecular mechanisms of each TCA cycle intermediate that may play key roles in regulating cellular immunity in cell stress and discuss its implication for immune activation and suppression.

Three-Year Effectiveness of Dimethyl Fumarate in Multiple Sclerosis: A Prospective Multicenter Real-World Study

BACKGROUND

Dimethyl fumarate (DMF) has demonstrated efficacy in phase III studies. However, real-world data are still limited.

OBJECTIVE

The objective of this study was to describe the profile of patients who receive DMF and to assess the effectiveness of DMF regarding relapses, disability progression, magnetic resonance imaging activity, and NEDA (No Evidence Disease Activity)-3 status in a Spanish population in a real-world setting.

METHODS

We conducted a multicenter prospective study of patients who started DMF between 2014 and 2019 in Spain. Three subgroups were considered: naïve, switch to DMF because of inefficacy, and switch to DMF because of adverse effects. The effects of DMF on clinical and radiological measures were evaluated.

RESULTS

Among 886 patients, 25.3% were naïve, 28.8% switched because of adverse effects, and 45.9% because of inefficacy. Median follow-up was 38.9 (interquartile range 22.6-41.8) months. Annualized relapse rates were 0.15, 0.10, and 0.10 at 12, 24, and 36 months respectively, and 77.7% of patients were relapse free at month 42. At 12, 24, and 42 months, 96.1%, 87.4%, and 79.7% of patients were progression free, respectively. The number of T1 gadolinium-enhancement (T1Gd+) lesions was 0.19, 0.14, and 0.18 at 12, 24, and 36 months. NEDA-3 status at month 42 was maintained by 49.8% of patients. Relapsing was associated with higher annualized relapse rates the year before (hazard ratio 1.34, p < 0.001) and to the inefficacy switch vs naïve group (hazard ratio 1.76, p = 0.003). A higher baseline Expanded Disability Status Scale score was associated with disability progression (hazard ratio 1.15, p = 0.003) and more T1Gd+ lesions (hazard ratio 1.07, p < 0.001) with radiological progression. A higher baseline Expanded Disability Status Scale score, a larger number of T1Gd+ lesions, and a switch because of inefficacy (vs adverse events) were all risk factors for losing NEDA-3 status. DMF was discontinued in 29.9% of patients, in 13.5% because of inefficacy.

CONCLUSIONS

Our findings confirm the sustained effectiveness of DMF on the clinical and radiological activity of multiple sclerosis in a real-world setting, both in naïve patients and in those switching from other multiple sclerosis therapies.

DNA methylation signatures of autoimmune diseases in human B lymphocytes

B lymphocytes play key roles in adaptive and innate immunity. In autoimmune diseases, their participation in disease instigation and/or progression has been demonstrated in both experimental models and clinical trials. Recent epigenetic investigations of human B lymphocyte subsets revealed the importance of DNA methylation in exquisitely regulating the cellular activation and differentiation programs. This review discusses recent advances on the potential of DNA methylation to shape events that impart generation of plasma cells and memory B cells, providing novel insight into homeostatic regulation of the immune system. In parallel, epigenetic profiling of B cells from patients with systemic or organo-specific autoimmune diseases disclosed distinctive differential methylation regions that, in some cases, could stratify patients from controls. Development of tools for editing DNA methylation in the mammalian genome could be useful for future functional studies of epigenetic regulation by offering the possibility to edit locus-specific methylation, with potential translational applications.

Dimethyl fumarate suppresses metastasis and growth of melanoma cells by inhibiting the nuclear translocation of NF-κB

BACKGROUND

Malignant melanoma is among the deadliest forms of skin cancers, and its incidence has been increasing over the past decades. In malignant melanoma, activation of the nuclear factor kappa B (NF-κB) promotes survival, migration, and invasion of cancer cells. Anti-NF-κB agents for treating metastatic melanoma would be beneficial, but no such drug is approved as either monotherapy or adjuvant therapy. Dimethyl fumarate (DMF) is an approved anti-inflammatory drug already in clinical use for psoriasis and multiple sclerosis.

OBJECTIVE

We investigated the anti-tumour effect of DMF treatment in metastatic melanoma in vitro and in vivo.

METHODS

The cell viability was assessed via trypan blue exclusion assay. The migration and invasion was analyzed in a Boyden chamber assay. The anti-metastatic effects and anti-tumour activity of DMF was determined in an in-vivo model. The expressions of NF-κB pathway and NF-κB regulatory proteins were detected via western blotting.

RESULTS

DMF decreased the cell viability, migration and invasion in vitro. In addition, DMF inhibited spontaneous metastasis and tumour growth. Mechanistically, DMF prevented the nuclear translocation of NF-κB, whereas no changes were observed in the phosphorylation levels of inhibitor of kappa B (IκB). In addition, DMF inhibited the expression of matrix metalloproteinases (MMPs) and very late antigens (VLAs). Furthermore, DMF treatment decreased the expression of Survivin and Bcl-extra large (Bcl-XL) proteins.

CONCLUSION

Our results suggest that DMF as a novel inhibitor of NF-κB may be a potential therapeutic agent for metastatic melanoma.

The role of natural products in revealing NRF2 function

Covering: up to 2020The transcription factor NRF2 is one of the body's major defense mechanisms, driving transcription of >300 antioxidant response element (ARE)-regulated genes that are involved in many critical cellular processes including redox regulation, proteostasis, xenobiotic detoxification, and primary metabolism. The transcription factor NRF2 and natural products have an intimately entwined history, as the discovery of NRF2 and much of its rich biology were revealed using natural products both intentionally and unintentionally. In addition, in the last decade a more sinister aspect of NRF2 biology has been revealed. NRF2 is normally present at very low cellular levels and only activated when needed, however, it has been recently revealed that chronic, high levels of NRF2 can lead to diseases such as diabetes and cancer, and may play a role in other diseases. Again, this "dark side" of NRF2 was revealed and studied largely using a natural product, the quassinoid, brusatol. In the present review, we provide an overview of NRF2 structure and function to orient the general reader, we will discuss the history of NRF2 and NRF2-activating compounds and the biology these have revealed, and we will delve into the dark side of NRF2 and contemporary issues related to the dark side biology and the role of natural products in dissecting this biology.

Immunomodulation by dimethyl fumarate treatment improves mouse sciatic nerve regeneration

Traumatic injury to the peripheral nervous system (PNS) often generates sensorimotor deficits that impair the quality of life of the patient. The success of nerve regeneration is related to tissue clearance and the formation of a microenvironment that sustains and stimulates axon growth up to the target. In this sense, macrophages are important for axon and myelin debris removal, neovascularization and the production of neurotrophic factors. Macrophage activation is improved by T helper (Th) lymphocytes, whose role remains few explored upon traumatic nerve injuries. Dimethyl fumarate (DMF) is the first-line drug for the treatment of multiple sclerosis due to its neuroprotective, anti-inflammatory and immunomodulatory properties. DMF improves nerve regeneration via antioxidant and cytoprotective cell signaling pathways. However, the direct activity on the cell immune response following nerve axotomy requires further investigation. In the present study, we evaluated DMF activity on Th cells and macrophage polarization, axonal regeneration and motor recovery following sciatic nerve crush in mice. For this aim, operated animals received DMF or vehicle once a day, starting at 3 days postinjury (dpi). Using an in vivo cell migration assay, we observed reduced lymphocyte infiltration in the nerves of DMF-treated mice at 7 dpi. Flow cytometry revealed DMF-responsive lymphocyte polarization from the pro- (Th1) to anti-inflammatory (Th2) phenotype at 7 dpi but not at 14 dpi. No effect was observed on macrophage polarization (from M1 to M2), although DMF reduced the frequency of the proinflammatory M1 subset from 7 to 14 dpi. Quantification of neurofilament (axon marker) and growth-associated protein 43 (GAP-43) immunolabeling showed improved axonal regeneration under DMF treatment at 14 dpi. Better motor recovery was observed in the DMF-treated group, as verified by an automated walking track test. Overall, our data reinforce the pro-regenerative capacity of DMF after traumatic nerve injury based on downmodulation of the proinflammatory immune response.

Dimethyl fumarate promotes B cell-mediated anti-inflammatory cytokine profile in B and T cells, and inhibits immune cell migration in patients with MS

Dimethyl Fumarate (DMF), known for its mechanism of action targeting Nrf2 and related redox homeostasis, is an approved immunotherapy for patients with Multiple Sclerosis (PwMS) in the relapsing form. We assessed how DMF modulates immune cell functions, namely the cytokine profile of co-cultured B and T cells, and the chemokine-mediated migration of immune cells. Following DMF therapy, LTα⁺, TNFα⁺ and IFNγ⁺ B cells were reduced while TGFβ and IL10 expression elevated. B cells from DMF-treated patients increased TGFβ and LTα expression on T cells, while DMF directly reduced TNFα⁺ and IFNγ⁺ T cells. CXCL12/CXCL13-mediated migration of B cells, Monocytes, CD4 and CD8 T cells was reduced, with altered CXCR5 and CXCR4 expression. Induction of regulatory B and T cells and reduced migration of immune cells may be part of the beneficial mechanism of DMF in PwMS.

Anti-inflammatory and anti-Candida Effects of Brazilian Organic Propolis, a Promising Source of Bioactive Molecules and Functional Food

Brazilian organic propolis (BOP) is an unexplored Brazilian propolis that is produced organically and certified according to international legislation. Our results showed that BOP has strong anti-inflammatory effects and acts by reducing nuclear factor κB activation, tumor necrosis factor α release, and neutrophil migration. In addition, BOP6 exhibited antifungal activity on planktonic and biofilm cultures of Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei, and Candida parapsisolis and reduced in vitro yeast cell adhesion to human keratinocytes at sub-inhibitory concentrations. BOP demonstrated significantly low toxicity in Galleria melonella larvae at antifungal doses. Lastly, a chemical analysis revealed the presence of caffeoyltartaric acid, 3,4-dicaffeoylquinic acid, quercetin, and gibberellins A7, A9, and A20, which may be responsible for the biological properties observed. Thus, our data indicate that BOP is a promising source of anti-inflammatory and antifungal molecules that may be used as a functional food.

Natural killer cells in multiple sclerosis: A review

As the most common non-traumatic disabling disease among adolescents, multiple sclerosis (MS) is a devastating neurological inflammatory disease of the central nervous system. Research has not yet fully elucidated its pathogenesis, but it has shown MS to be a complex, multifactorial disease with many interplaying factors. One of these factors, natural killer (NK) cells, lymphocytes of the innate immune system, have recently gained attention due to the effects of daclizumab therapy, causing an expansion of the immunoregulatory subset of NK cells. Since then, NK cells and their relation to MS have been the focus of research, with many new findings being published in the last decade. In this review, NK cells are pictured as potent cytotoxic killers, as well as unique immune-regulators. Additionally, an overview of our current knowledge regarding NK cells in MS is given. The role of NK cells in MS is reviewed in the context of well-established environmental factors and current disease modifying therapies to gain further understanding of the pathogenesis and treatment options in MS.

Improving the Gastrointestinal Tolerability of Fumaric Acid Esters: Early Findings on Gastrointestinal Events with Diroximel Fumarate in Patients with Relapsing-Remitting Multiple Sclerosis from the Phase 3, Open-Label EVOLVE-MS-1 Study

INTRODUCTION

Diroximel fumarate (DRF) is a novel oral fumarate in development for patients with relapsing forms of multiple sclerosis (MS). Clinical findings from the DRF development program suggest that rates of gastrointestinal (GI) treatment-emergent adverse events (TEAEs) and discontinuation due to GI TEAEs are low, based on clinical and real-world observations of other fumaric acid esters, including dimethyl fumarate (DMF). The incidence of GI TEAEs varies from 40 to 88% in clinical and real-world studies of DMF. The objective of this study is to present GI tolerability findings from the EVOLVE-MS-1 study and present biologic hypotheses for the improved GI properties of DRF.

METHODS

GI TEAEs and treatment discontinuation because of GI TEAEs were assessed in DRF-treated patients with relapsing-remitting MS who were participating in the ongoing, 96-week, open-label, phase 3 EVOLVE-MS-1 study.

RESULTS

As of March 30, 2018, a total of 696 patients were enrolled in EVOLVE-MS-1. GI TEAEs were reported in 30.9% (215/696) of patients; the vast majority (96%; 207/215) experienced events that were mild or moderate in severity. When GI AEs did occur, they occurred early in treatment, resolved (88.8%; 191/215), and were of short duration [median 7.5 (range 1-87) days] in most patients. GI TEAEs led to < 1% of patients discontinuing treatment.

CONCLUSIONS

We suggest that the distinct chemical structure of DRF contributes to the observed low rates of GI TEAEs and GI-associated treatment discontinuations, possibly due to a combination of several factors. We hypothesize that these factors may include less reactivity with off-target proteins and/or lower production of a methanol leaving group that may contribute to GI irritation. A direct comparison of GI tolerability with DRF versus DMF is being evaluated in the EVOLVE-MS-2 study.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT02634307.

FUNDING

Alkermes Inc. (Waltham, MA, USA) and Biogen (Cambridge, MA, USA).