Immune cell targeted fumaric esters support a role of GPR109A as a primary target of monomethyl fumarate in vivo.

Dimethyl fumarate (DMF) is approved as a treatment for multiple sclerosis (MS), however, its mode of action remains unclear. One hypothesis proposes that Michael addition to thiols by DMF, notably glutathione is immunomodulatory. The alternative proposes that monomethyl fumarate (MMF), the hydrolysis product of DMF, is a ligand to the fatty acid receptor GPR109A found in the lysosomes of immune cells. We prepared esters of MMF and macrolides derived from azithromycin, which were tropic to immune cells by virtue of lysosomal trapping. We tested the effects of these substances in an assay of response to Lipopolysaccharide (LPS) in freshly isolated human peripheral blood mononuclear cells (PBMCs). In this system, we observed that the 4'' ester of MMF (compound 2 and 3) reduced levels of Interleukins (IL)-1ß, IL-12 and tumor necrosis factor alpha (TNFα) significantly at a concentration of 1 µM, while DMF required about 25 µM for the same effect. The 2' esters of MMF (compound 1 and 2) were, like MMF itself, inactive in vitro. The 4'' ester formed glutathione conjugates rapidly while the 2' conjugates did not react with thiols but did hydrolyze slowly to release MMF in these cells. We then tested the substances in vivo using the imiquimod/isostearate model of psoriasis where the 2' ester was the most active at 0.06-0.12 mg/kg (approximately 0.1 µmol/kg), improving skin score, body weight and cytokine levels (TNFα, IL-17A, IL-17F, IL-6, IL-1ß, NLRP3 and IL-23A). In contrast, the thiol reactive 4'' ester was less active than the 2' ester while DMF was ca. 300-fold less active. The thiol reactive 4'' ester was not easily recovered from either plasma or organs while the 2' ester exhibited conventional uptake and elimination. The 2' ester also reduced levels of IL-6 in acute monosodium urate (MSU) induced inflammation. These data suggest that mechanisms that are relevant in vivo center on the release of MMF. Given that GPR109A is localized to the lysosome, and that lysosomal trapping increases 2' ester activity by > 300 fold, these data suggest that GPR109A may be the main target in vivo. In contrast, the effects associated with glutathione (GSH) conjugation in vitro are unlikely to be as effective in vivo due to the much lower dose in use which cannot titrate the more concentrated thiols. These data support the case for GPR109A modulation in autoimmune diseases.

Characterization of the modification of Kelch-like ECH-associated protein 1 by different fumarates.

Fumarates (fumaric acid esters), primarily dimethyl fumarate (DMF) and monoethyl fumarate (MEF) and its salts, are orally administered systemic agents used for the treatment of psoriasis and multiple sclerosis. It is widely believed that the pharmaceutical activities of fumarates are exerted through the Keap1-Nrf2 pathway. Although it has been revealed that DMF and MEF differentially modify specific Keap1 cysteine residues and result in the differential activation of Nrf2, how the modification of DMF and MEF impacts the biochemical properties of Keap1 has not been well characterized. Here, we found that both DMF and MEF can only modify the BTB domain of Keap1 and that only C151 is accessible for covalent binding in vitro. Dynamic fluorescence scanning (DSF) assays showed that the modification of DMF to Keap1 BTB increased its thermal stability, while the modification of MEF dramatically decreased its thermal stability. Further crystal structures revealed no significant conformational variation between the DMF-modified and MEF-modified BTBs. Overall, our biochemical and structural study provides a better understanding of the covalent modification of fumarates to Keap1 and may suggest fundamentally different mechanisms adopted by fumarates in regulating the Keap1-Nrf2 pathway.

MiR-142-3p regulates synaptopathy-driven disease progression in multiple sclerosis.

AIM: We recently proposed miR-142-3p as a molecular player in inflammatory synaptopathy, a new pathogenic hallmark of multiple sclerosis (MS) and of its mouse model experimental autoimmune encephalomyelitis (EAE), that leads to neuronal loss independently of demyelination. MiR-142-3p seems to be unique among potential biomarker candidates in MS, since it is an inflammatory miRNA playing a dual role in the immune and central nervous systems. Here, we aimed to verify the impact of miR-142-3p circulating in the cerebrospinal fluid (CSF) of MS patients on clinical parameters, neuronal excitability and its potential interaction with disease modifying therapies (DMTs). METHODS AND RESULTS: In a cohort of 151 MS patients, we found positive correlations between CSF miR-142-3p levels and clinical progression, IL-1ß signalling as well as synaptic excitability measured by transcranial magnetic stimulation. Furthermore, therapy response of patients with 'low miR-142-3p' to dimethyl fumarate (DMF), an established disease-modifying treatment (DMT), was superior to that of patients with 'high miR-142-3p' levels. Accordingly, the EAE clinical course of heterozygous miR-142 mice was ameliorated by peripheral DMF treatment with a greater impact relative to their wild type littermates. In addition, a central protective effect of this drug was observed following intracerebroventricular and ex vivo acute treatments of EAE wild type mice, showing a rescue of miR-142-3p-dependent glutamatergic alterations. By means of electrophysiology, molecular and biochemical analysis, we suggest miR-142-3p as a molecular target of DMF. CONCLUSION: MiR-142-3p is a novel and potential negative prognostic CSF marker of MS and a promising tool for identifying personalised therapies.

First-line therapy in relapsing remitting multiple sclerosis.

Today, first-line treatments for multiple sclerosis include injectable immunomodulators - some of which have been on the market for nearly 25 years - as well as teriflunomide and dimethyl fumarate, which are more recent, but have opened the way for oral treatments. These drugs are considered similar in effectiveness, and their safety and side-effect profiles are generally reassuring. These treatments have been associated with a reduction in radiological and clinical disease activity, and a positive effect on patient quality of life, especially when introduced early in the disease process. This article will discuss data on first-line treatments currently available in France, their effectiveness and safety, and their place in pediatric patients and in woman who plan to become pregnant.

Distinct Nrf2 Signaling Mechanisms of Fumaric Acid Esters and Their Role in Neuroprotection against 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Induced Experimental Parkinson's-Like Disease.

UNLABELLED: A promising approach to neurotherapeutics involves activating the nuclear-factor-E2-related factor 2 (Nrf2)/antioxidant response element signaling, which regulates expression of antioxidant, anti-inflammatory, and cytoprotective genes. Tecfidera, a putative Nrf2 activator, is an oral formulation of dimethylfumarate (DMF) used to treat multiple sclerosis. We compared the effects of DMF and its bioactive metabolite monomethylfumarate (MMF) on Nrf2 signaling and their ability to block 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced experimental Parkinson's disease (PD). We show that in vitro DMF and MMF activate the Nrf2 pathway via S-alkylation of the Nrf2 inhibitor Keap1 and by causing nuclear exit of the Nrf2 repressor Bach1. Nrf2 activation by DMF but not MMF was associated with depletion of glutathione, decreased cell viability, and inhibition of mitochondrial oxygen consumption and glycolysis rates in a dose-dependent manner, whereas MMF increased these activities in vitro However, both DMF and MMF upregulated mitochondrial biogenesis in vitro in an Nrf2-dependent manner. Despite the in vitro differences, both DMF and MMF exerted similar neuroprotective effects and blocked MPTP neurotoxicity in wild-type but not in Nrf2 null mice. Our data suggest that DMF and MMF exhibit neuroprotective effects against MPTP neurotoxicity because of their distinct Nrf2-mediated antioxidant, anti-inflammatory, and mitochondrial functional/biogenetic effects, but MMF does so without depleting glutathione and inhibiting mitochondrial and glycolytic functions. Given that oxidative damage, neuroinflammation, and mitochondrial dysfunction are all implicated in PD pathogenesis, our results provide preclinical evidence for the development of MMF rather than DMF as a novel PD therapeutic. SIGNIFICANCE STATEMENT: Almost two centuries since its first description by James Parkinson, Parkinson's disease (PD) remains an incurable disease with limited symptomatic treatment. The current study provides preclinical evidence that a Food and Drug Administration-approved drug, dimethylfumarate (DMF), and its metabolite monomethylfumarate (MMF) can block nigrostriatal dopaminergic neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of PD. We elucidated mechanisms by which DMF and its active metabolite MMF activates the redox-sensitive transcription factor nuclear-factor-E2-related factor 2 (Nrf2) to upregulate antioxidant, anti-inflammatory, mitochondrial biosynthetic and cytoprotective genes to render neuroprotection via distinct S-alkylating properties and depletion of glutathione. Our data suggest that targeting Nrf2-mediated gene transcription using MMF rather than DMF is a promising approach to block oxidative stress, neuroinflammation, and mitochondrial dysfunction for therapeutic intervention in PD while minimizing side effects.

Dimethyl- and monomethylfumarate regulate indoleamine 2,3-dioxygenase (IDO) activity in human immune cells.

Fumaric acid esters (FAEs) are used as an oral treatment for psoriasis. Dimethylfumarate (DMF) and its metabolite monomethylfumarate (MMF) are regarded as the pharmacologically active moieties. Indoleamine 2,3-dioxygenase (IDO) is the key enzyme for the metabolism of tryptophan. The kynurenine pathway is established as a major regulator of innate and adaptive immunity. Here, we investigated the effect of DMF and MMF on IDO activity and expression in human peripheral blood mononuclear cells (PBMCs). IDO activity was determined by measuring the concentration of kynurenine in the culture medium using a HPLC technique. IDO and kynureninase protein expressions were analysed by Western blot. Our results demonstrated that DMF and MMF dose-dependently reduced the levels of L-kynurenine in PBMCs activated by interferon-γ (IFN-γ). Furthermore, MMF had an inhibitory effect on IDO activity in vitro with an ED50 of 10 µmol/L, a value within the therapeutic concentration range for this molecule. We also observed that IDO and kynureninase expressions were reduced in PBMCs in a dose-dependent manner by DMF and MMF. The results of our study show that DMF and MMF (in therapeutic concentrations) inhibited IDO and kynureninase activity and expression in a NF-κB-dependent manner in PBMCs while also decreasing the level of L-kynurenine in these cells. As we found that FAEs inhibit both IDO expression and enzymatic activity leading to a modulation of tryptophan degradation, we believe this effect may contribute to the clinical efficacy of this drug in psoriasis by downregulating pro-inflammatory mediators generated by the kynurenine pathway.

Sniping the scout: Targeting the key molecules in dendritic cell functions for treatment of autoimmune diseases.

Dendritic cells (DCs) are a power tool for manipulating immune system. They play important roles in the induction of immunity as well as inducing intrathymic and peripheral tolerance. After generated from stem cells in the bone marrow, DCs traffic to the peripheral tissues, where they capture and process antigens, express lymphocyte co-stimulators, migrate to the secondary lymph organs and present the processed antigen to naive T cells to either activate or tolerize them. These processes are modulated subtly and influenced by various factors. Aberrant regulation of the processes may cause autoimmunity. Investigation into the biology of DCs and the molecules and mechanisms that regulate them helps us understanding the pathogenesis of autoimmune diseases and reveals numerous steps for pharmacological manipulation. In this review, we made a sketch line of the critical events of DC biology that are potential pharmacologic targets for the treatment of autoimmune diseases.

Scientific evidence for the use of current traditional systemic therapies in patients with hidradenitis suppurativa.

Traditional systemic therapies are frequently prescribed for the treatment of hidradenitis suppurativa (HS). Clinicians consider antibiotics, retinoids, antiandrogens, immunosuppressants, and less common treatment, such as fumarates, in the management of HS. Different classes of medications have been selected to treat HS based on their ability to target various pathways of the condition. Concerns about infection, such as infection with Clostridium difficile, necessitates switching therapy or shortening the course of therapy with specific antibiotics. This review explores the outcomes with the use of numerous medical therapies and postulates explanations for their efficacy or lack of response. Data on long-term safety and efficacy with traditional systemic therapies are lacking.

A new polymorph of bis(2-aminopyridinium) fumarate-fumaric acid (1/1) from powder X-ray diffraction.

A new polymorph of bis(2-aminopyridinium) fumarate-fumaric acid (1/1), 2C5H7N2⁺∙C4H2O4²â»-·C4H4O4, was obtained and its crystal structure determined by powder X-ray diffraction. The new polymorph (form II) crystallizes in the triclinic system (space group P-1), while the previous reported polymorph [form I; Ballabh, Trivedi, Dastidar & Suresh (2002). CrystEngComm, 4, 135-142; Büyükgüngör, Odabasoglu, Albayrak & Lönnecke (2004). Acta Cryst. C60, o470-o472] is monoclinic (space group P21/c). In both forms I and II, the asymmetric unit consists of one 2-aminopyridinium cation, half a fumaric acid molecule and half a fumarate dianion. The fumarate dianion is involved in hydrogen bonding with two neighbouring 2-aminopyridinium cations to form a hydrogen-bonded trimer in both forms. In form II, the hydrogen-bonded trimers are interlinked across centres of inversion via pairs of N-H∙∙∙O hydrogen bonds, whereas such trimers are joined via single N-H∙∙∙O hydrogen bonds in form I, leading to different packing modes for forms I and II. The results demonstrate the relevance and application of the powder diffraction method in the study of polymorphism of organic molecular materials.

Bis(4-acetoxy-N-ethyl-N-n-propyl-tryptammonium) fumarate-fumaric acid (1/1).

The solid-state structure of the title salt/adduct (systemic name: bis-{[2-(4-acet-yloxy-1H-indol-3-yl)eth-yl](eth-yl)propyl-aza-nium} but-2-enedioate-(E)-butenedioic acid (1/1)), 2C17H25N2O2 +·C4H2O4 2-·C4H4O4, was determined by single-crystal X-ray diffraction. The asymmetric unit consists of a singly protonated tryptammonium cation, one half of a fumarate dianion and one half of a fumaric acid mol-ecule. In the crystal, the ions and mol-ecules are linked together in infinite chains propagating along [001] through a series of N-H⋯O and O-H⋯O hydrogen bonds.

Vaccine response in people with multiple sclerosis treated with fumarates.

People with multiple sclerosis (pwMS) have an increased risk of infection. As disease-modifying therapies (DMTs) and other treatments may interact with the immune system, there may be concerns about vaccine efficacy and safety. Therefore, it is important to evaluate possible interactions between DMTs and vaccines. The fumarates, dimethyl fumarate, diroximel fumarate, and monomethyl fumarate, are approved for the treatment of relapsing multiple sclerosis. This review assesses the evidence on vaccine response in pwMS treated with fumarates, with a particular focus on COVID-19 vaccines. Treatment with fumarates does not appear to result in blunting of humoral responses to vaccination; for COVID-19 vaccines, particularly RNA-based vaccines, evidence indicates antibody responses similar to those of healthy recipients. While data on the effect of fumarates on T-cell responses are limited, they do not indicate any significant blunting. COVID-19 vaccines impart a similar degree of protection against severe COVID-19 infection for pwMS on fumarates as in the general population. Adverse reactions following vaccination are generally consistent with those observed in the wider population; no additional safety signals have emerged in those on fumarates. Additionally, no increase in relapse has been observed in pwMS following vaccination. In pwMS receiving fumarates, vaccination is generally safe and elicits protective immune responses.

Bis(oxotremorine) fumarate bis-(fumaric acid).

The title compound, bis-(oxotremorine) fumarate bis-(fumaric acid) {systematic name: 1-[4-(2-oxopyrrolidin-1-yl)but-2-yn-yl]pyrrolidinium (2E)-but-2-ene-di-o-ate bis-[(2E)-but-2-enedioic acid]}, 2C12H19N2O+·C4H2O4 2-·2C4H4O4, has a single oxotremorine monocation protonated at the pyrrolidine nitro-gen, one fumaric acid mol-ecule and half of a fumarate dianion in the asymmetric unit. The ions and fumaric acid mol-ecules are held together by N-H⋯O and O-H-⋯O hydrogen bonds in 40-membered rings with graph-set notation R 6 6(40). The fumarate ions join these rings into infinite chains along [001].

Psilacetin derivatives: fumarate salts of the meth-yl-ethyl, meth-yl-allyl and diallyl variants of the psilocin prodrug.

The solid-state structures of the salts of three psilacetin derivatives, namely, 4-acet-oxy-N-eth-yl-N-methyl-tryptammonium (4-AcO-MET) hydro-fumarate {sys-tematic name: [2-(4-acet-yloxy-1H-indol-3-yl)eth-yl](meth-yl)ethyl-aza-nium 3-carb-oxy-prop-2-enoate}, C15H21N2O2 +·C4H3O4 -, 4-acet-oxy-N-allyl-N-methyl-tryptammonium (4-AcO-MALT) hydro-fumarate {systematic name: [2-(4-acet-yl-oxy-1H-indol-3-yl)eth-yl](meth-yl)prop-2-enyl-aza-nium 3-carb-oxy-prop-2-eno-ate}, C16H21N2O2 +·C4H3O4 -, and 4-acet-oxy-N,N-di-allyl-tryptammonium (4-AcO-DALT) fumarate-fumaric acid (1/1) (systematic name: bis-{[2-(4-acet-yloxy-1H-indol-3-yl)eth-yl]diprop-2-enyl-aza-nium} but-2-enedioate-(E)-butenedioic acid (1/1)), 2C18H23N2O2 +·C4H2O4 2-·C4H4O4, are reported. All three salts possess a protonated tryptammonium cation. The 4-AcO-MET and 4-AcO-MALT compounds are charge-balanced by 3-carb-oxy-acrylate (hydro-fumarate) anions. The 4-AcO-DALT complex crystallizes as a two-to-one tryptammonium-to-fumarate salt, which co-crystallizes with a fumaric acid mol-ecule. Each structure is consolidated by N-H⋯O and O-H⋯O hydrogen bonds.

Emerging Therapeutic Applications for Fumarates.

Fumarates are successfully used for the treatment of psoriasis and multiple sclerosis. Their antioxidative, immunomodulatory, and neuroprotective properties make fumarates attractive therapeutic candidates for other pathologies. The exact working mechanisms of fumarates are, however, not fully understood. Further elucidation of the mechanisms is required if these drugs are to be successfully repurposed for other diseases. Towards this, administration route, dosage, and treatment timing, frequency, and duration are important parameters to consider and optimize with clinical paradigms in mind. Here, we summarize the rapidly expanding literature on the pharmacokinetics and pharmacodynamics of fumarates, including a discussion on two recently FDA-approved fumarates VumerityTM and BafiertamTM. We review emerging applications of fumarates, focusing on neurological and cardiovascular diseases.

Role of dimethyl fumarate in the treatment of glioblastoma multiforme: A review article.

Glioblastoma multiforme (GBM), the most frequent malignant and aggressive primary brain tumor, is characterized by genetically unstable heterogeneous cells, diffused growth pattern, microvascular proliferation, and resistance to chemotherapy. Extensive investigations are being carried out to identify the molecular origin of resistance to chemo- and radio-therapy in GBM and find novel targets for therapy to improve overall survival rate. Dimethyl fumarate (DMF) has been shown to be a safe drug with limited short and long-term side effects, and fumaric acid esters (FAEs), including DMF, present both anti-oxidative and anti-inflammatory activity in different cell types and tissues. DMF has also anti-tumoral and neuroprotective effects and so it could be repurposed in the treatment of this invasive tumor in the future. Here, we have reviewed DMF pharmacokinetics and different mechanisms by which DMF could have therapeutic effects on GBM.

Methyl Fumarate-Derived Iron Carbonyl Complexes (FumET-CORMs) as Powerful Anti-inflammatory Agents.

Autoimmune diseases are characterized by dendritic cell (DC)-driven activation of pro-inflammatory T cell responses. Therapeutic options for these severe diseases comprise small molecules such as dimethyl fumarate, or "gasotransmitters" such as CO. Herein we describe the synthesis of bifunctional enzyme-triggered CO-releasing molecules (ET-CORMs) that allow the simultaneous intracellular release of both CO and methyl fumarate. Using bone-marrow-derived DCs the impressive therapeutic potential of these methyl fumarate-derived compounds (FumET-CORMs) is demonstrated by strong inhibition of lipopolysaccharide-induced pro-inflammatory signaling pathways and blockade of downstream interleukin-12 or -23 production. The data also show that FumET-CORMs are able to transform DCs into an anti-inflammatory phenotype. Thus, these novel compounds have great clinical potential, for example, for the treatment of psoriasis or other inflammatory conditions of the skin.

Drug-induced Fanconi syndrome associated with fumaric acid esters treatment for psoriasis: a case series.

BACKGROUND: Fumaric acid esters (FAEs), an oral immunomodulating treatment for psoriasis and multiple sclerosis, have been anecdotally associated with proximal renal tubular dysfunction due to a drug-induced Fanconi syndrome. Few data are available on clinical outcomes of FAE-induced Fanconi syndrome. METHODS: Descriptive case series with two cases of Fanconi syndrome associated with FAE treatment diagnosed at two Dutch university nephrology departments, three cases reported at the Dutch and German national pharmacovigilance databases and six previously reported cases. RESULTS: All 11 cases involved female patients with psoriasis. The median age at the time of onset was 38 years [interquartile range (IQR) 37-46]. Patients received long-term FAEs treatment with a median treatment duration of 60 months (IQR 28-111). Laboratory tests were typically significant for low serum levels of phosphate and uric acid, while urinalysis showed glycosuria and proteinuria. Eight (73%) patients had developed a hypophosphataemic osteomalacia and three (27%) had pathological bone fractures. All patients discontinued FAEs, while four (36%) patients were treated with supplementation of phosphate and/or vitamin D. Five (45%) patients had persisting symptoms despite FAEs discontinuation. CONCLUSIONS: FAEs treatment can cause drug-induced Fanconi syndrome, but the association has been reported infrequently. Female patients with psoriasis treated long term with FAEs seem to be particularly at risk. Physicians treating patients with FAEs should be vigilant and monitor for the potential occurrence of Fanconi syndrome. Measurement of the urinary albumin:total protein ratio is a suggested screening tool for tubular proteinuria in Fanconi syndrome.

Induction therapy with a combination of fumarates and cyclosporine: A benefit for the patient?

Fumarates or fumaric acid esters derivates (FAED) have appeared to be effective and less toxic than other systemic treatments for psoriasis. Due to its safe adverse event profile, FAED can be used as a long-term maintenance therapy. One of the greatest reasons why FAED are not preferred as a first-line treatment is that according to the recommended dosing schedule, clinically meaningful improvement is seen just after 6 to 8 weeks of therapy. In this manuscript, we suppose an alternative induction scheme with a combination therapy of fumarates and cyclosporine for a more rapid improvement and better compliance.

Fumaric acid esters in the management of psoriasis.

Fumaric acid esters (FAE) are small molecules with immunomodulating, anti-inflammatory, and anti-oxidative effects. FAE were introduced as a systemic psoriasis treatment in 1959 and empirically developed further between 1970 and 1990 in Germany, Switzerland, and the Netherlands. The development of FAE as psoriasis treatment did not follow the traditional drug development phases. Nonetheless, in 1994 FAE were approved in Germany for the treatment of severe plaque psoriasis. FAE are currently one of the most commonly used treatments in Germany, and FAE are increasingly being used as an unlicensed treatment in several other European countries. To date, six randomized controlled trials and 29 observational studies have evaluated FAE in a combined total of 3,439 patients. The efficacy and safety profile of FAE is favorable. About 50%-70% of patients achieve at least 75% improvement in psoriasis severity after 16 weeks of treatment. Common adverse events of FAE include gastrointestinal complaints and flushing symptoms, which lead to treatment discontinuation in up to 40% of patients. Lymphocytopenia, eosinophilia, and proteinuria are commonly observed during FAE treatment, but rarely require treatment discontinuation. The long-term safety profile of continuous FAE treatment is favorable without an increased risk for infections, malignancies, or other serious adverse events. There are no known drug-interactions for FAE. The 2009 European evidence-based S3-guidelines on psoriasis treatment recommend FAE and suggest it as a first-line systemic treatment for moderate-to-severe plaque psoriasis. This review is aimed to give an overview of FAE treatment in the management of psoriasis.