Beneficial Effects of Dimethyl Fumarate on Experimental Autoimmune Myocarditis

Dimethyl fumarate attenuates lipopolysaccharide-induced mitochondrial injury by activating Nrf2 pathway in cardiomyocytes

AIMS

To determine whether dimethyl fumarate (DMF) can protect against lipopolysaccharide (LPS) -induced myocardial injury.

MAIN METHODS

H9c2 cells pretreated with or without DMF were stimulated with LPS. Cell viability and apoptosis were evaluated. Nrf2 and HO-1 expression were detected using Western blotting. Mitochondrial morphology, mitochondrial superoxide production were observed using confocal microscope. Mitochondrial respiration function was measured using Seahorse bioanalyzer.

KEY FINDINGS

(1) The cell viability decreased, LDH release and apoptosis increased in LPS- challenged H9c2 cells. DMF pretreatment brought a higher cell viability, and a lower LDH leakage and apoptosis than those of LPS group (P < 0.01). (2) DMF pretreatment resulted in an increased Nrf2 and HO-1 expression, and enhanced nuclear Nrf2 level in LPS-challenged cells (P < 0.01). (3) Nrf2-siRNA could inhibit DMF-induced enhancement of HO-1 expression and cell viability, and partly abolish DMF-induced reduction of LDH leakage and apoptosis. (4) ERK1/2 inhibitor PD98059 could not only prevent the DMF-induced enhancement of nuclear Nrf2 and HO-1, but also inhibit DMF-induced increase in cell viability. (5) Compared with LPS-challenged cells, DMF pretreatment caused a lower production of mitochondrial superoxide and a higher mitochondrial membrane potential, which could be abolished by Nrf2-siRNA. (6) DMF could attenuate LPS-induced mitochondrial fragmentation and improve mitochondrial respiration function by enhancement of the oxygen consumption rate of basal respiration and ATP production in LPS-challenged cells (P < 0.01).

SIGNIFICANCE

DMF protects cardiomyocytes against LPS-induced damage. ERK1/2-dependent activation of Nrf2/HO-1 pathway is responsible for DMF-induced cardioprotection via reduction of oxidative stress, improvement of mitochondrial morphology and energy metabolism.

Lipopolysaccharide Binding Protein and Oxidative Stress in a Multiple Sclerosis Model

Recent findings in experimental autoimmune encephalomyelitis (EAE) suggest that altering certain bacterial populations present in the gut may lead to a proinflammatory condition, that could result in the development of multiple sclerosis (MS). Also, Reactive Oxygen Species seem to be involved in the course of MS. In this study, it has been aimed to relate all these variables starting from an analysis of the lipopolysaccharide (LPS) and LPS-binding protein (LBP) with the determination of parameters related to oxidative stress in the blood, brain and spinal cord. For this purpose, samples obtained from EAE rats and relapsing-remitting (RRMS) MS patients were used. In addition, EAE rats were treated with Natalizumab, N-acetyl-cysteine and dimethyl fumarate. Natalizumab was also employed in RRMS. The results of this study revealed an improvement in the clinical symptoms of the EAE and MS with the treatments, as well as a reduction in the oxidative stress parameters and in LBP. Correlations between the clinical variables of the disease, i.e. oxidative damage and LBP, were established. Although the conclusions of this research are indeed relevant, further investigation would be necessary to establish the intrinsic mechanisms of the MS-oxidative stress-microbiota relationship.

Dimethyl Fumarate and Monomethyl Fumarate Promote Post-Ischemic Recovery in Mice

Oxidative stress plays an important role in cerebral ischemia-reperfusion injury. Dimethyl fumarate (DMF) and its primary metabolite monomethyl fumarate (MMF) are antioxidant agents that can activate the nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway and induce the expression of antioxidant proteins. Here, we evaluated the impact of DMF and MMF on ischemia-induced brain injury and whether the Nrf2 pathway mediates the effects provided by DMF and MMF in cerebral ischemia-reperfusion injury. Using a mouse model of transient focal brain ischemia, we show that DMF and MMF significantly reduce neurological deficits, infarct volume, brain edema, and cell death. Further, DMF and MMF suppress glial activation following brain ischemia. Importantly, the protection of DMF and MMF was mostly evident during the subacute stage and was abolished in Nrf2-/- mice, indicating that the Nrf2 pathway is required for the beneficial effects of DMF and MMF. Together, our data indicate that DMF and MMF have therapeutic potential in cerebral ischemia-reperfusion injury and their protective role is likely mediated by the Nrf2 pathway.

Dimethylfumarate Impairs Neutrophil Functions

Host defense against pathogens relies on neutrophil activation. Inadequate neutrophil activation is often associated with chronic inflammatory diseases. Neutrophils also constitute a significant portion of infiltrating cells in chronic inflammatory diseases, for example, psoriasis and multiple sclerosis. Fumarates improve the latter diseases, which so far has been attributed to the effects on lymphocytes and dendritic cells. Here, we focused on the effects of dimethylfumarate (DMF) on neutrophils. In vitro, DMF inhibited neutrophil activation, including changes in surface marker expression, reactive oxygen species production, formation of neutrophil extracellular traps, and migration. Phagocytic ability and autoantibody-induced, neutrophil-dependent tissue injury ex vivo was also impaired by DMF. Regarding the mode of action, DMF modulates-in a stimulus-dependent manner-neutrophil activation using the phosphoinositide 3-kinase/Akt-p38 mitogen-activated protein kinase and extracellular signal-regulated kinase 1/2 pathways. For in vivo validation, mouse models of epidermolysis bullosa acquisita, an organ-specific autoimmune disease caused by autoantibodies to type VII collagen, were employed. In the presence of DMF, blistering induced by injection of anti-type VII collagen antibodies into mice was significantly impaired. DMF treatment of mice with clinically already-manifested epidermolysis bullosa acquisita led to disease improvement. Collectively, we demonstrate a profound inhibitory activity of DMF on neutrophil functions. These findings encourage wider use of DMF in patients with neutrophil-mediated diseases.

Dimethyl fumarate attenuates experimental autoimmune neuritis through the nuclear factor erythroid-derived 2-related factor 2/hemoxygenase-1 pathway by altering the balance of M1/M2 macrophages

Background

Guillain–Barré syndrome (GBS) is an acute, post-infectious, immune-mediated, demyelinating disease of peripheral nerves and nerve roots. Dimethyl fumarate (DMF), a fumaric acid ester, exhibits various biological activities, including multiple immunomodulatory and neuroprotective effects. However, the potential mechanism underlying the effect of DMF in GBS animal model experimental autoimmune neuritis (EAN) is unclear.

Methods

Using EAN, an established GBS model, we investigated the effect of DMF by assessing clinical score, histological staining and electrophysiological studies. Then, we further explored the potential mechanism by Western blot analysis, flow cytometry, fluorescence immunohistochemistry, PCR, and ELISA analysis. The Mann–Whitney U test was used to compare differences between control group and treatment groups where appropriate.

Results

DMF treatment reduced the neurological deficits by ameliorating inflammatory cell infiltration and demyelination of sciatic nerves. In addition, DMF treatment decreased the level of pro-inflammatory M1 macrophages while increasing the number of anti-inflammatory M2 macrophages in the spleens and sciatic nerves of EAN rats. In RAW 264.7, a shift in macrophage polarization from M1 to M2 phenotype was demonstrated to be depended on DMF application. In sciatic nerves, DMF treatment elevated the level of the antioxidant transcription factor nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and its target gene hemoxygenase-1 (HO-1) which could facilitate macrophage polarization toward M2 type. Moreover, DMF improved the inflammatory milieu in spleens of EAN rats, characterized by downregulation of messenger RNA (mRNA) of IFN-γ, TNF-α, IL-6, and IL-17 and upregulation of mRNA level of IL-4 and IL-10.

Conclusions

Taken together, our data demonstrate that DMF can effectively suppress EAN, and the mechanism involves altering the balance of M1/M2 macrophages and attenuating inflammation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0559-x) contains supplementary material, which is available to authorized users.

Recent advances in the biomedical applications of fumaric acid and its ester derivatives: The multifaceted alternative therapeutics

Several lines of evidence have demonstrated the potential biomedical applications of fumaric acid (FA) and its ester derivatives against many human disease conditions. Fumaric acid esters (FAEs) have been licensed for the systemic treatment of the immune-mediated disease psoriasis. Biogen Idec Inc. announced about the safety and efficacy of the formulation FAE (BG-12) for treating RRMS (relapsing-remitting multiple sclerosis). Another FAE formulation DMF (dimethyl fumarate) was found to be capable of reduction in inflammatory cardiac conditions, such as autoimmune myocarditis and ischemia and reperfusion. DMF has also been reported to be effective as a potential neuroprotectant against the HIV-associated neurocognitive disorders (HAND). Many in vivo studies carried out on rat and mice models indicated inhibitory effects of fumaric acid on carcinogenesis of different origins. Moreover, FAEs has emerged as an important matrix ingredient in the fabrication of biodegradable scaffolds for tissue engineering applications. Drug delivery vehicles composed of FAEs have shown promising results in delivering some leading drug molecules. Apart from these specific applications and findings, many more studies on FAEs have revealed new therapeutic potentials with the scope of clinical applications. However, until now, this scattered vital information has not been written into a collective account and analyzed for minute details. The aim of this paper is to review the advancement made in the biomedical application of FA and FAEs and to focus on the clinical investigation and molecular interpretation of the beneficial effects of FA and FAEs.

Dimethylfumarate protects against TNF-α-induced secretion of inflammatory cytokines in human endothelial cells

Background

Inflammation, angiogenesis and oxidative stress have been implicated in the pathogenesis of various vascular diseases. Recent evidence suggests that dimethylfumarate (DMF), an antiposriatic and anti-multiple sclerosis agent, possesses anti-inflammatory, anti-oxidative and anti-angiogenic properties. Here, we analyze the influence of DMF on TNF-α-induced expression of the important pro-inflammatory and pro-atherogenic chemokine MCP-1 and investigate the underlying mechanisms of this expression.

Findings

We analyzed constitutive and TNF-α-induced expression of MCP-1 in human umbilical vascular endothelial cells (HUVEC) +/− DMF treatment via enzyme-linkes immunosorbent assay (ELISA). DMF significantly inhibited the protein expression levels in a time- and concentration-dependent manner. Furthermore, MCP-1 mRNA expression was also reduced in response to DMF, as demonstrated by RT-PCR. Thus, the regulation occurs at the transcriptional level. Interestingly, DMF prolonged the TNF-α-induced p38 and JNK phosphorylation in HUVEC, as demonstrated by Western blot analysis; however, the p38 and JNK inhibitor SB203580 did not affect the DMF-conveyed suppression of TNF-α-induced MCP-1 expression. DMF suppressed the TNF-α-induced nuclear translocation and phosphorylation (Serine 536) of p65 in these cells. These results were additionally approved by p65 luciferase promoter assays. Furthermore, we found that DMF slightly inhibited the early degradation of IκBα. In addition, we verified our results using other important inflammatory cytokines such as CCL-5, PDGF-BB, GM-CSF and IL-6.

Conclusion

DMF suppresses various TNF-α-induced pro-inflammatory and pro-atherogenic cytokines/chemokines in human endothelial cells. This action is regulated by reduced p65 activity and nuclear translocation, which can be explained in part by the reduced early degradation of IκBα and more important the reduced phosphorylation of p65 at Serine 536. These effects were independent of the p38, PI3K and p42/44 signaling pathways. As a result, DMF might be suitable for treating patients with vascular diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-015-0094-z) contains supplementary material, which is available to authorized users.

Design of oral agents for the management of multiple sclerosis: benefit and risk assessment for dimethyl fumarate

Dimethyl fumarate (DMF) is the most recent oral disease-modifying therapy approved by the US Food and Drug Administration and is indicated for the treatment of relapsing forms of multiple sclerosis (MS). Prior to approval for use in MS, DMF and its active metabolite, monomethyl fumarate, had been used for decades as two of the fumaric acid esters in Fumaderm, a medication used in Europe for the treatment of psoriasis. The unique mechanism of action of DMF remains under evaluation; however, it has been shown to act through multiple pathways leading to shifts away from the Th1 proinflammatory response to the less inflammatory Th2 response. Preliminary data suggest that DMF may induce neuroprotective effects in central nervous system white matter, although further studies are needed to demonstrate these effects on inflammatory demyelination. The DMF Phase III clinical trials demonstrated its efficacy with regard to a reduction in the annualized relapse rate and reductions in new or enlarging T2 lesions and numbers of gadolinium-enhancing lesions on magnetic resonance imaging. DMF has a well-defined safety profile, given the experience with its use in the treatment of psoriasis, and more recently from the DMF clinical trials program and post-marketing era for treatment of MS. The safety profile and oral mode of administration of DMF place it as an attractive first-line therapy option for the treatment of relapsing forms of MS. Long-term observational studies will be needed to determine the effects of DMF on progression of disability in MS.

Allergic contact dermatitis from dimethyl fumarate after contact with a Chinese sofa

BACKGROUND

Dimethyl fumarate has been successfully used in the treatment of psoriasis in the past. Despite its clinical use, cutaneous contact with this molecule may cause contact dermatitis.

OBJECTIVE

We report a case in which skin exposure to a synthetic fabric sofa containing dimethyl fumarate made by a Chinese furniture manufacturer resulted in a severe, pruritic, papulovesicular, eczematous dermatitis to the sites of contact with the sofa.

METHODS

The patient was patch-tested with serial dilutions of dimethyl fumarate.

RESULTS

Patch testing results revealed strong positive reactions to dimethyl fumarate at different concentrations.

CONCLUSION

Dimethyl fumarate is a potent contact sensitizer and is commonly found in sachets inside furniture and footwear boxes.

The anti-inflammatory effects of dimethyl fumarate in astrocytes involve glutathione and haem oxygenase-1

DMF (dimethyl fumarate) exerts anti-inflammatory and pro-metabolic effects in a variety of cell types, and a formulation (BG-12) is being evaluated for monotherapy in multiple sclerosis patients. DMF modifies glutathione (GSH) levels that can induce expression of the anti-inflammatory protein HO-1 (haem oxygenase-1). In primary astrocytes and C6 glioma cells, BG-12 dose-dependently suppressed nitrite production induced by either LI [LPS (lipopolysaccharide) at 1 μg/ml plus IFNγ (interferon γ) at 20 units/ml] or a mixture of pro-inflammatory cytokines, with greater efficacy in C6 cells. BG-12 reduced NOS2 (nitric oxide synthase 2) mRNA levels and activation of a NOS2 promoter, reduced nuclear levels of NF-κB (nuclear factor κB) p65 subunit and attenuated loss of IκBα (inhibitory κBα) in both cell types, although with greater effects in astrocytes. In astrocytes, LI decreased mRNA levels for GSHr (GSH reductase) and GCL (c-glutamylcysteine synthetase), and slightly suppressed GSHs (GSH synthetase) mRNAs. Co-treatment with BG-12 prevented those decreased and increased levels above control values. In contrast, LI reduced GSHp (GSH peroxidase) and GCL in C6 cells, and BG-12 had no effect on those levels. BG-12 increased nuclear levels of Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2), an inducer of GSH-related enzymes, in astrocytes but not C6 cells. In astrocytes, GSH was decreased by BG-12 at 2 h and increased at 24 h. Prior depletion of GSH using buthionine-sulfoximine increased the ability of BG-12 to reduce nitrites. In astrocytes, BG-12 increased HO-1 mRNA levels and effects on nitrite levels were blocked by an HO-1 inhibitor. These results demonstrate that BG-12 suppresses inflammatory activation in astrocytes and C6 glioma cells, but with distinct mechanisms, different dependence on GSH and different effects on transcription factor activation.