Blocking reverse electron transfer-mediated mitochondrial DNA oxidation rescues cells from PANoptosis.

PANoptosis is a new type of cell death featured with pyroptosis, apoptosis and necroptosis, and is implicated in organ injury and mortality in various inflammatory diseases, such as sepsis and hemophagocytic lymphohistiocytosis (HLH). Reverse electron transport (RET)-mediated mitochondrial reactive oxygen species (mtROS) has been shown to contribute to pyroptosis and necroptosis. In this study we investigated the roles of mtROS and RET in PANoptosis induced by TGF-ß-activated kinase 1 (TAK1) inhibitor 5Z-7-oxozeaenol (Oxo) plus lipopolysaccharide (LPS) as well as the effects of anti-RET reagents on PANoptosis. We showed that pretreatment with anti-RET reagents 1-methoxy PMS (MPMS) or dimethyl fumarate (DMF) dose-dependently inhibited PANoptosis in macrophages BMDMs and J774A.1 cells induced by Oxo/LPS treatment assayed by propidium iodide (PI) staining. The three arms of the PANoptosis signaling pathway, namely pyroptosis, apoptosis and necroptosis signaling, as well as the formation of PANoptosomes were all inhibited by MPMS or DMF. We demonstrated that Oxo/LPS treatment induced RET and mtROS in BMDMs, which were reversed by MPMS or DMF pretreatment. Interestingly, the PANoptosome was co-located with mitochondria, in which the mitochondrial DNA was oxidized. MPMS and DMF fully blocked the mtROS production and the formation of PANoptosome induced by Oxo plus LPS treatment. An HLH mouse model was established by poly(I:C)/LPS challenge. Pretreatment with DMF (50 mg·kg-1·d-1, i.g. for 3 days) or MPMS (10 mg·kg-1·d-1, i.p. for 2 days) (DMF i.g. MPMS i.p.) effectively alleviated HLH lesions accompanied by decreased hallmarks of PANoptosis in the liver and kidney. Collectively, RET and mtDNA play crucial roles in PANoptosis induction and anti-RET reagents represent a novel class of PANoptosis inhibitors by blocking oxidation of mtDNA, highlighting their potential application in treating PANoptosis-related inflammatory diseases. PANoptotic stimulation induces reverse electron transport (RET) and reactive oxygen species (ROS) in mitochondia, while 1-methoxy PMS and dimethyl fumarate can inhibit PANoptosis by suppressing RETmediated oxidation of mitochondrial DNA.

Dimethyl Fumarate Ameliorated Cardiorenal Anemia Syndrome and Improved Overall Survival in Dahl/Salt-Sensitive Rats.

Cardiovascular disease, chronic kidney disease, and anemia are known to adversely affect each other. Inflammation is commonly involved in these diseases. Cardiorenal anemia syndrome (CRAS) is the name given to this mutually harmful condition. Dimethyl fumarate (DMF) is a Food and Drug Administration-approved antioxidant and anti-inflammatory agent. The purpose of this study was to investigate the effects of DMF on Dahl/salt-sensitive (DS) rats as a CRAS model. Six-week-old DS rats were divided into three groups: the control group, the high-salt (HS) group, and the HS+DMF group. The HS and HS+DMF groups were fed a high-salt diet (8% NaCl) from 6 weeks of age. In the HS+DMF group, DMF (90 mg/kg per day) was orally administered from 6 to 15 weeks of age. Systolic blood pressure was measured every 2 weeks. The heart and renal injuries were assessed with histopathological analysis. The heart and renal expression of mRNAs was assessed by reverse-transcription polymerase chain reaction. DMF significantly improved overall survival, which was shortened by HS in DS rats. Systolic blood pressure increased in the HS group compared with the control group, and DMF tended to suppress this change. DMF ameliorated the cardiac and renal abnormalities confirmed in the HS group by histopathological analysis. Furthermore, the changes in mRNA expressions associated with disease exacerbation in the HS group were suppressed by DMF. DMF also improved anemia. This study suggests that DMF improves overall survival in DS rats through organ-protective effects and is effective against cardiorenal anemia syndrome. SIGNIFICANCE STATEMENT: Dimethyl fumarate was found to improve overall survival in Dahl/salt-sensitive rats, associated with its ability to ameliorate anemia and induce cardioprotective and renoprotective effects through anti-inflammatory and antifibrotic effects.

Experimental Investigations of Monomethyl and Dimethyl Fumarate in an Astrocyte-Microglia Co-Culture Model of Inflammation.

INTRODUCTION: Multiple sclerosis (MS) is the most common chronic inflammatory, demyelinating disease of the central nervous system. Dimethyl fumarate (DMF) and monomethyl fumarate (MMF) belong to the disease-modifying drugs in treatment of MS. There is evidence that astrocytes and microglia are involved in MS pathology, but few studies are available about MMF and DMF effects on astrocytes and microglia. The aim of this study was to investigate the effects of MMF and DMF on microglial activation and morphology as well as potential effects on glial viability, Cx43, and AQP4 expressions in different set-ups of an in vitro astrocyte-microglia co-culture model of inflammation. METHODS: Primary rat glial co-cultures of astrocytes containing 5% (M5, mimicking "physiological" conditions) or 30% (M30, mimicking "pathological, inflammatory" conditions) of microglia were treated with different concentrations of MMF (0.1, 0.5, and 2 µg/mL) or DMF (1.5, 5, and 15 µM) for 24 h. Viability, proliferation, and cytotoxicity of glial cells were examined using MTT assay. Immunocytochemistry was performed to analyze the microglial phenotypes. Connexin 43 (Cx43) and aquaporin 4 (AQP4) expressions were quantified by immunoblot analysis. RESULTS: Treatment with different concentrations of MMF or DMF for 24 h did not change the glial cell viability in M5 and M30 co-cultures. Microglial phenotypes were not altered by DMF under physiological M5 conditions, but treatment with higher concentration of DMF (15 µM) induced microglial activation under inflammatory M30 conditions. Incubation with different concentrations of MMF had no effects on microglial phenotypes. The Cx43 expression in M5 and M30 co-cultures was not changed significantly by immunoblot analysis after incubation with different concentrations of DMF or MMF for 24 h. The AQP4 expression was significantly increased in M5 co-cultures after incubation with 5 µm DMF. Under the other conditions, AQP4 expression was not affected by DMF or MMF. DISCUSSION: In different set-ups of the astrocyte-microglia co-culture model of inflammation, MMF has not shown significant effects. DMF had only limited effects on microglia phenotypes and AQP4 expression. In summary, mechanisms of action of fumarates probably do not involve direct effects on microglia phenotypes as well as Cx43 and AQP4 expression.

The effects of dimethyl fumarate on cytoplasmic LPS-induced noncanonical pyroptosis in periodontal ligament fibroblasts and dental pulp cells.

AIM: Pyroptosis is a type of inflammatory cell death and is related to pulpitis and apical periodontitis. In this study, the aim was to investigate how periodontal ligament fibroblasts (PDLFs) and dental pulp cells (DPCs) respond to pyroptotic stimuli and explore whether dimethyl fumarate (DMF) could block pyroptosis in PDLFs and DPCs. METHODOLOGY: Three methods (stimulation with lipopolysaccharide [LPS] plus nigericin, poly(dA:dT) transfection and LPS transfection) were used to induce pyroptosis in PDLFs and DPCs, two types of fibroblasts related to pulpitis and apical periodontitis. THP-1 cell was used as a positive control. Afterwards, PDLFs and DPCs were treated with or without DMF before inducing pyroptosis to examine the inhibitory effect of DMF. Pyroptotic cell death was measured by lactic dehydrogenase (LDH) release assays, cell viability assays, propidium iodide (PI) staining and flow cytometry. The expression levels of cleaved gasdermin D N-terminal (GSDMD NT), caspase-1 p20, caspase-4 p31 and cleaved PARP were examined by immunoblotting. Immunofluorescence analysis was used to detect the cellular distribution of GSDMD NT. RESULTS: Periodontal ligament fibroblasts and DPCs were more sensitive to cytoplasmic LPS-induced noncanonical pyroptosis than to canonical pyroptosis induced by stimulation with LPS priming plus nigericin or by poly(dA:dT) transfection. In addition, treatment with DMF attenuated cytoplasmic LPS-induced pyroptotic cell death in PDLFs and DPCs. Mechanistically, it was shown that the expression and plasma membrane translocation of GSDMD NT were inhibited in DMF-treated PDLFs and DPCs. CONCLUSIONS: This study indicates that PDLFs and DPCs are more sensitive to cytoplasmic LPS-induced noncanonical pyroptosis and that DMF treatment blocks pyroptosis in LPS-transfected PDLFs and DPCs by targeting GSDMD, suggesting DMF might be a promising drug for the management of pulpitis and apical periodontitis.

Stability indicating RP-HPLC method for determination of dimethyl fumarate in presence of its main degradation products: Application to degradation kinetics.

A stability-indicating reverse phase-high-perfromance liquid chromatography method for the quantitative determination of dimethyl fumarate in presence of its main degradation products was developed. The chromatographic conditions were optimized using two-level full factorial design, chromatographic analysis was performed using Inertsil® column (250 × 4.6 mm, 5 µm) maintained at 25°C. Mobile phase was a mixture of water (pH 2.6 adjusted with phosphoric acid) and methanol (40:60, v/v) at a flow rate 1.0 mL/min, detection was performed at 210 nm using diode array detector. Stress degradation of dimethyl fumarate under acidic, alkaline, neutral, oxidative, photolytic, and thermal conditions was carried out, it was found to be very susceptible to hydrolysis under acidic and alkaline conditions; further investigation of degradation kinetics over pH range 1-9 was carried out. The degradation rate constant (K), t1/2 and t90 were calculated. Dimethyl fumarate show decreasing in stability in the following pH order: 7 < 5 < 3 < 1 < 9. The method was validated as per ICH guidelines, the method was found to be linear over concentration range 10-150 µg/mL with coefficient of determination (r2 ) 0.9997. The method was successfully applied for dimethyl fumarate determination in Marclerosis® dosage form within run time less than eight minutes without interference from excipients.

Dimethyl fumarate mediates Nrf2-dependent mitochondrial biogenesis in mice and humans.

The induction of mitochondrial biogenesis could potentially alleviate mitochondrial and muscle disease. We show here that dimethyl fumarate (DMF) dose-dependently induces mitochondrial biogenesis and function dosed to cells in vitro, and also dosed in vivo to mice and humans. The induction of mitochondrial gene expression is more dependent on DMF's target Nrf2 than hydroxycarboxylic acid receptor 2 (HCAR2). Thus, DMF induces mitochondrial biogenesis primarily through its action on Nrf2, and is the first drug demonstrated to increase mitochondrial biogenesis with in vivo human dosing. This is the first demonstration that mitochondrial biogenesis is deficient in Multiple Sclerosis patients, which could have implications for MS pathophysiology and therapy. The observation that DMF stimulates mitochondrial biogenesis, gene expression and function suggests that it could be considered for mitochondrial disease therapy and/or therapy in muscle disease in which mitochondrial function is important.

A review of the mechanisms of action of dimethylfumarate in the treatment of psoriasis.

Fumaric acid esters (FAEs) such as dimethylfumarate (DMF) are used for the treatment of adults with moderate-to-severe psoriasis. The mode of action of FAEs is complex. Here, we provide a comprehensive review of the literature to describe the molecular mechanisms by which DMF and its active metabolite monomethylfumarate (MMF) exert their anti-inflammatory and immune modulatory effects. MMF can bind to the hydroxy-carboxylic acid receptor 2 (HCA2) on the cell surface and both DMF and MMF react with intracellular glutathione following cell penetration. DMF and to some extent also MMF modulate the activity of certain cellular signalling proteins such as the nuclear factor (erythroid-derived 2)-like 2 (Nrf2), nuclear factor kappa B (Nf-κB) and the cellular concentration of cyclic adenosine monophosphate. Some studies show that DMF can also affect the hypoxia-inducible factor 1-alpha (HIF-1α). These actions seem to be responsible for i) the downregulation of inflammatory cytokines and ii) an overall shift from a proinflammatory Th1/Th17 response to an anti-inflammatory/regulatory Th2 response. Both steps are necessary for the amelioration of psoriatic inflammation, although additional mechanisms have been proposed. There is a growing body of evidence to support the notion that DMF/MMF may also exert effects on granulocytes and non-immune cell lineages including keratinocytes and endothelial cells. A better understanding of the multiple molecular mechanisms involved in the cellular action of FAEs will help to adapt and further improve the use of such small molecules for the treatment of psoriasis and other chronic inflammatory diseases.

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.

Dimethyl fumarate induces cardiac developmental toxicity in zebrafish via down-regulation of oxidative stress.

Dimethyl fumarate (DMF) is an immunosuppressant commonly used to treat multiple sclerosis and other autoimmune diseases. Despite known side effects such as lymphopenia, the effect of DMF on cardiac development remains unclear. To assess this, we used zebrafish to evaluate the cardiac developmental toxicity of DMF. Our study showed that DMF reduced the survival rate of zebrafish embryos, with those exposed to 1, 1.3, and 1.6 mg/L exhibiting heart rate reduction, shortened body length, delayed yolk sac absorption, pericardial edema, increased distance from sinus venous to bulbus arteriosus, and separation of cardiomyocytes and endocardial cells at 72 hpf. Heart development-related genes showed disorder, apoptosis-related genes were up-regulated, and the oxidative stress response was down-regulated. Treatment with cysteamine ameliorated the heart development defects. Our study demonstrates that DMF induces cardiac developmental toxicity in zebrafish, possibly by down-regulating oxidative stress responses. This study provides a certain research basis for further study of DMF-induced cardiac developmental toxicity, and provides some experimental evidence for future clinical application and study of DMF.

Amelioration of inflammation through reduction of oxidative stress in rheumatoid arthritis by treating fibroblast-like synoviocytes (FLS) with DMF-loaded PLGA nanoparticles.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory condition, and Dimethyl fumarate (DMF) is known for inducing antioxidant enzymes and reducing reactive oxygen species (ROS). Fibroblast-like synoviocytes (FLS) contribute to joint damage by releasing interleukins (IL-1ß, IL-6, and IL-8) in response to ROS. Given ROS's impact on FLS acquiring an invasive phenotype, our study explored the effects of poly lactic-co-glycolic acid (PLGA) nanoparticles containing DMF on the expression of the HO-1 enzyme and the inflammatory cytokines IL-1ß, IL-6, and IL-8 in FLS cells. METHODS: In this study, we evaluated and compared the impact of Free-DMF and PLGA-DMF, on the gene expression of the HO-1 and inflammatory cytokines (IL-1ß, IL-6, and IL-8) in FLS cells derived from 13 patients with rheumatoid arthritis. qRT-PCR method was used to quantify the gene expression levels. RESULTS: PLGA-DMF nanoparticles demonstrated a significant increase in HO-1 expression and a significant decrease in IL-1ß gene expression. Also, a significant decrease in IL-6 gene expression was seen under the effect of Free-DMF. These results indicate the potential effectiveness of PLGA-DMF nanoparticles in reducing inflammation and improving rheumatoid arthritis symptoms. DISCUSSION: According to the findings, PLGA-DMF nanoparticles are expected to be effective in reducing inflammation and improving the symptoms of rheumatoid arthritis. Also, further studies on other factors affected by oxidative stress such as cell invasion factors and survival factors after the effect of PLGA-DMF nanoparticle are recommended.

Dimethyl fumarate protects against hepatic ischemia-reperfusion injury by alleviating ferroptosis via the NRF2/SLC7A11/HO-1 axis.

Dimethyl fumarate (DMF), a therapeutic agent for relapsing-remitting multiple sclerosis, has cytoprotective and antioxidant effects. Ferroptosis, a pathological cell death process, is recently shown to play a vital part in ischemia-reperfusion injury (IRI). This study aimed to unveil the suppressive role of DMF on ferroptosis in liver IRI. The anti-ferroptosis effect of DMF on hepatic IRI was investigated using a liver IRI mouse model and a hypoxia-reoxygenation injury (HRI) model in alpha mouse liver (AML12) cells. Serum transaminase concentrations reflected liver function. Hematoxylin and eosin staining was used to assess liver damage. Cell viability was evaluated utilizing the CCK-8 assay. Malondialdehyde (MDA), the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, and BODIPY 581/591C11 were measured to estimate the injury caused by lipid peroxidation. Western blotting and real-time polymerase chain reaction (RT-PCR) were performed to explore the underlying molecular mechanisms. We demonstrated the anti-ferroptosis effects of DMF both in vivo and in vitro. DMF treatment ameliorated hepatic IRI. KEGG enrichment analysis and transmission electron microscopy revealed a close relationship between ferroptosis and liver IRI. Furthermore, DMF protected against HRI by inhibiting ferroptosis via activating the nuclear factor E2-related factor 2 (NRF2) pathway. Interestingly, NRF2 knockdown notably decreased the expression of SLC7A11 and HO-1 and blocked the anti-ferroptosis effects of DMF. DMF inhibits ferroptosis by activating the NRF2/SLC7A11/HO-1 axis and exerts a protective effect against hepatic IRI.

Dimethyl fumarate possesses antiplatelet and antithrombotic properties.

BACKGROUND: Dimethyl fumarate (DMF) is a methyl ester of fumaric acid and has been approved for treating multiple sclerosis (MS) and psoriasis due to anti-inflammatory effect. There is a close association between platelets and the pathogenesis of MS. Whether DMF affects platelet function remains unclear. Our study intends to evaluate DMF's effect on platelet function. METHODS: Washed human platelets were treated with different concentrations of DMF (0, 50, 100 and 200 µM) at 37 °C for 1 h followed by analysis of platelet aggregation, granules release, receptors expression, spreading and clot retraction. In addition, mice received intraperitoneal injection of DMF (15 mg/kg) to assess tail bleeding time, arterial and venous thrombosis. RESULTS: DMF significantly inhibited platelet aggregation and the release of dense/alpha granules in response to collagen-related peptide (CRP) or thrombin stimulation dose-dependently without altering the expression of platelet receptors αIIbß3, GPIbα, and GPVI. In addition, DMF-treated platelets presented significantly reduced spreading on collagen or fibrinogen and thrombin-mediated clot retraction along with the decreased phosphorylation of c-Src and PLCγ2. Moreover, administration of DMF into mice significantly prolonged the tail bleeding time and impaired arterial and venous thrombus formation. Furthermore, DMF reduced the generation of intracellular reactive oxygen species and calcium mobilization, and inhibited NF-κB activation and the phosphorylation of ERK1/2, p38 and AKT. CONCLUSION: DMF inhibits platelet function and arterial/venous thrombus formation. Considering the presence of thrombotic events in MS, our study indicates that DMF treatment for patients with MS might obtain both anti-inflammatory and anti-thrombotic benefits.

The Modulatory Effects of DMF on Microglia in Aged Mice Are Sex-Specific.

There is a striking sex-related difference in the prevalence of many neurodegenerative diseases, highlighting the need to consider whether treatments may exert sex-specific effects. A change in microglial activation state is a common feature of several neurodegenerative diseases and is considered to be a key factor in driving the inflammation that characterizes these conditions. Among the changes that have been described is a switch in microglial metabolism towards glycolysis which is associated with production of inflammatory mediators and reduced function. Marked sex-related differences in microglial number, phenotype and function have been described in late embryonic and early postnatal life in rodents and some reports suggest that sexual dimorphism extends into adulthood and age and, in models of Alzheimer's disease, the changes are more profound in microglia from female, compared with male, mice. Dimethyl fumarate (DMF) is a fumaric acid ester used in the treatment of psoriasis and relapsing remitting multiple sclerosis and, while its mechanism of action is unclear, it possesses anti-inflammatory and anti-oxidant properties and also impacts on cell metabolism. Here we treated 16-18-month-old female and male mice with DMF for 1 month and assessed its effect on microglia. The evidence indicates that it exerted sex-specific effects on microglial morphology and metabolism, reducing glycolysis only in microglia from female mice. The data suggest that this may result from its ability to inactivate glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

Ozone at low concentration modulates microglial activity in vitro: A multimodal microscopy and biomolecular study.

Oxygen-ozone (O2 -O3 ) therapy is an adjuvant/complementary treatment based on the activation of antioxidant and cytoprotective pathways driven by the nuclear factor erythroid 2-related factor 2 (Nrf2). Many drugs, including dimethyl fumarate (DMF), that are used to reduce inflammation in oxidative-stress-related neurodegenerative diseases, act through the Nrf2-pathway. The scope of the present investigation was to get a deeper insight into the mechanisms responsible for the beneficial result of O2 -O3 treatment in some neurodegenerative diseases. To do this, we used an integrated approach of multimodal microscopy (bright-field and fluorescence microscopy, transmission and scanning electron microscopy) and biomolecular techniques to investigate the effects of the low O3 concentrations currently used in clinical practice in lipopolysaccharide (LPS)-activated microglial cells human microglial clone 3 (HMC3) and in DMF-treated LPS-activated (LPS + DMF) HMC3 cells. The results at light and electron microscopy showed that LPS-activation induced morphological modifications of HMC3 cells from elongated/branched to larger roundish shape, cytoplasmic accumulation of lipid droplets, decreased electron density of the cytoplasm and mitochondria, decreased amount of Nrf2 and increased migration rate, while biomolecular data demonstrated that Heme oxygenase 1 gene expression and the secretion of the pro-inflammatory cytokines, Interleukin-6, and tumor necrosis factor-α augmented. O3 treatment did not affect cell viability, proliferation, and morphological features of both LPS-activated and LPS + DMF cells, whereas the cell motility and the secretion of pro-inflammatory cytokines were significantly decreased. This evidence suggests that modulation of microglia activity may contribute to the beneficial effects of the O2 -O3 therapy in patients with neurodegenerative disorders characterized by chronic inflammation. HIGHLIGHTS: Low-dose ozone (O3 ) does not damage activated microglial cells in vitro Low-dose O3 decreases cell motility and pro-inflammatory cytokine secretion in activated microglial cells in vitro Low-dose O3 potentiates the effect of an anti-inflammatory drug on activated microglial cells.

Dimethyl fumarate improves cognitive deficits in chronic cerebral hypoperfusion rats by alleviating inflammation, oxidative stress, and ferroptosis via NRF2/ARE/NF-κB signal pathway.

Cerebrovascular disease and its risk factors cause persistent decrease of cerebral blood flow, chronic cerebral hypoperfusion (CCH) is the major foundation of vascular cognitive impairment (VCI). The hippocampus is extremely vulnerable to cerebral ischemia and hypoxia. Oxidative stress and neuroinflammation injury are important pathophysiological mechanisms of this process, which is closely related to hippocampal neurons damage and loss. Dimethyl fumarate (DMF), an FDA-approved therapeutic for multiple sclerosis (MS), plays a protective role in multiple neurological disorders. Studies have shown that DMF exerts anti-inflammatory and antioxidant effects via the NRF2/ARE/NF-κB signaling pathway. Thus, this study aimed to evaluate the neuroprotective effect of DMF in the CCH rat model. Ferroptosis, a novel defined iron-dependent cell death form, were found to be strongly associated with the pathophysiology of CCH. Emerging evidences have shown that inhibition of ferroptosis by targeting NRF2 exerted neuroprotective effect in neurodegeneration diseases. We also investigated whether DMF can alleviate cognitive deficits through inhibition of ferroptosis by the NRF2 signaling pathway in this study. DMF was intragastric for consecutive five weeks (100 mg/kg/day). Then behavior test and histological, molecular, and biochemical analysis were performed. We found that DMF treatment significantly improved cognitive deficits and partially reversed hippocampus neuronal damage and loss caused by CCH. And DMF treatment decreased hippocampus IL-1ß, TNF-α, and IL-6 pro-inflammatory cytokines concentration, and mediated the NF-κB signaling pathway. And DMF also alleviated hippocampus oxidative stress through reducing MDA, and increasing GSH and SOD levels, which are also closely associated with ferroptosis. Besides, DMF treatment reduced the expression of PTGS2, and increased the expression of FTH1 and xCT, and the iron content is also reduced, which were the important features related to ferroptosis. Furthermore, DMF activated the NRF2/ARE signaling pathway and upregulated the expression of HO-1, NQO1 and GPX4. These outcomes indicated that DMF can improve cognitive impairment in rats with CCH, possibly through alleviating neuroinflammation, oxidative stress damage and inhibiting ferroptosis of hippocampal neurons. Overall, our results provide new evidence for the neuroprotective role of DMF.

Activation of Nrf2 Pathway by Dimethyl Fumarate Attenuates Renal Ischemia-Reperfusion Injury.

BACKGROUND: Dimethyl fumarate (DMF) is a novel antioxidant that selectively reduces hydroxyl radicals. This study aimed to investigate the potential role of DMF in the pathogenesis of renal ischemia-reperfusion injury (IRI) and the mechanisms involved. METHODS: C57BL/6 wild-type mice were treated with DMF or a vehicle. Subsequently, renal IRI was induced in mice by a model of right kidney nephrectomy and left renal ischemia for 30 minutes followed by reperfusion for 24 hours. Sham operation and phosphate-buffered saline were used as controls. Serum and renal tissues were collected at 24 hours after IRI to evaluate the influence of DMF on the recovery of renal function after IRI. Blood urea nitrogen and serum creatinine levels were measured. Kidney cell apoptosis was evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling-positive staining. Interleukin 6 and tumor necrosis factor α cytokines in the kidney tissues were measured. Indicators of oxidative stress in the kidneys were detected. Finally, Nrf2-deficient mice were used to determine the protective role of the nuclear factor erythroid 2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone 1 (NQO1) signaling pathways induced by DMF using western blot assay. RESULTS: DMF significantly attenuated renal dysfunction in mice and showed reductions in the severity of renal tubular injury, cell necrosis, and apoptosis. Moreover, DMF significantly reduced the amount of key inflammatory mediators. Additionally, DMF attenuated the malondialdehyde levels 24 hours after IRI but upregulated the superoxide dismutase activities. Western blot assay showed that DMF significantly increased the protein levels of Nrf2, HO-1, and NQO-1. Importantly, these DMF-mediated beneficial effects were not observed in Nrf2-deficient mice. CONCLUSIONS: DMF attenuates renal IRI by reducing inflammation and upregulating the antioxidant capacity, which may be through Nrf2/HO-1and NQO1 signaling pathway.

Dimethyl fumarate does not mitigate cognitive decline and ß-amyloidosis in female APPPS1 mice.

INTRODUCTION: Alzheimer's disease (AD) is the leading cause of dementia and a major global health issue. Currently, only limited treatment options are available to patients. One possibility to expand the treatment repertoire is repurposing of existing drugs such as dimethyl fumarate (DMF). DMF is approved for treatment of multiple sclerosis and previous animal studies have suggested that DMF may also have a beneficial effect for the treatment of AD. METHODS: We used an APPPS1 transgenic model of senile ß-amyloidosis and treated female mice orally with DMF in two treatment paradigms (pre and post onset). We quantified learning and memory parameters, ß-amyloidosis, and neuroinflammation to determine the potential of DMF as AD therapeutics. RESULTS: Treatment with DMF had no influence on water maze performance, ß-amyloid accumulation, plaque formation, microglia activation, and recruitment of immune cells to the brain. Compared to vehicle-treated animals, oral DMF treatment could not halt or retard disease progression in the mice. DISCUSSION: Our results do not favour the use of DMF as treatment for AD. While our results stand in contrast to previous findings in other models, they emphasize the importance of animal model selection and suggest further studies to elucidate the mechanisms leading to conflicting results.

Structural insights into the multiple binding modes of Dimethyl Fumarate (DMF) and its analogs to the Kelch domain of Keap1.

The activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription function has been implicated in the protection of neurodegenerative diseases. The cytoplasmic protein, Kelch-like ECH-associated protein 1 (Keap1), negatively regulates Nrf2. The Keap1-Nrf2 pathway is a potential therapeutic target for tackling free-radical damage. Dimethyl fumarate (DMF) is currently an approved drug for the treatment of relapsing multiple sclerosis. Recent studies showed that DMF modifies the reactive cysteines in the BTB domain of Keap1 and thus activates Nrf2 transcription function. Intriguingly, our crystal structure studies revealed that DMF also binds to the ß-propeller domain (Keap1-DC) of Keap1. The crystal structure of the complex, refined to 1.54 Å resolution, revealed unexpected features: DMF binds (a) to the Nrf2-binding site (bottom region of Keap1-DC, site 1) with moderate interaction, and (b) to the top region of Keap1-DC, near to the blade II (site 2). The specificity of the binding 'site 2' was found to be unique to blade II of the ß-propeller domain. The newly identified 'site 2' region in Keap1-DC may have a different functional role to regulate Nrf2. Moreover, the crystal structures of Keap1-DC in complex with the DMF analogs, including monoethyl fumarate, fumarate, and itaconate, also exhibited similar binding modes with Keap1-DC. Binding studies confirmed that DMF binds, in a nanomolar range, to the Keap1-DC region as well as the BTB domain of Keap1. Furthermore, the competitive binding assay in the presence of the Nrf2 peptide affirmed the direct binding of DMF at the Nrf2-binding region of Keap1-DC. Overall, our studies suggest that the drug molecule, DMF, binds at multiple sites of Keap1 and thus potentially activates Nrf2 function through covalent as well as the noncovalent mode of action, to combat oxidative stress. DATABASE: Structural data are available in RCSB-protein data bank database(s) under the accession numbers 6LRZ, 7C60, and 7C5E.

Dimethylfumarate Inhibits Colorectal Carcinoma Cell Proliferation: Evidence for Cell Cycle Arrest, Apoptosis and Autophagy.

Recent studies have proven that Dimethylfumarate (DMF) has a marked anti-proliferative impact on diverse cancer entities e.g., on malignant melanoma. To explore its anti-tumorigenic potential, we examined the effects of DMF on human colon carcinoma cell lines and the underlying mechanisms of action. Human colon cancer cell line HT-29 and human colorectal carcinoma cell line T84 were treated with or without DMF. Effects of DMF on proliferation, cell cycle progression, and apoptosis were analyzed mainly by Bromodeoxyuridine (BrdU)- and Lactatdehydrogenase (LDH)assays, caspase activation, flowcytometry, immunofluorescence, and immunoblotting. In addition, combinational treatments with radiation and chemotherapy were performed. DMF inhibits cell proliferation in both cell lines. It was shown that DMF induces a cell cycle arrest in G0/G1 phase, which is accompanied by upregulation of p21 and downregulation of cyclin D1 and Cyclin dependent kinase (CDK)4. Furthermore, upregulation of autophagy associated proteins suggests that autophagy is involved. In addition, the activation of apoptotic markers provides evidence that apoptosis is involved. Our results show that DMF supports the action of oxaliplatin in a synergetic manner and failed synergy with radiation. We demonstrated that DMF has distinct antitumorigenic, cell dependent effects on colon cancer cells by arresting cell cycle in G0/G1 phase as well as activating both the autophagic and apoptotic pathways and synergizes with chemotherapy.

Effect of dimethyl fumarate on neuroinflammation and apoptosis in pentylenetetrazol kindling model in rats.

OBJECTIVE: Role of apoptosis and neuroinflammation have been well established in the pathogenesis of epilepsy. It has been reported that the activation of nuclear factor-erythroid 2-related factor-2 (Nrf2) contributes to the attenuation of inflammation by inhibiting nuclear factor-kB (NF-kB) pathway. Therefore, the present study was designed to evaluate anti-inflammatory and anti-apoptotic role of dimethyl fumarate (DMF), an activator of Nrf2, in chemical kindling model in rats. METHODS: Chemical kindling model was established in Wistar rats by intraperitoneal (i.p.) administration of pentylenetetrazole (PTZ). Animals were treated with DMF (60 mg/kg) to activate the Nrf2 antioxidant response element (ARE) pathway. The animals were assessed for seizure score, neuronal damage and inflammatory cytokines levels (IL-1ß, IL-6 and TNF-α) in hippocampus. The mRNA levels of various genes (Nrf2, HO-1, NQO1, Bcl2, Bax, Caspase 3, NF-kB, IL-6, IL-1ß and TNF-α) were quantified by real-time PCR. The expression of anti-oxidative (Nrf2), apoptotic (Bax, Bcl2) and inflammatory (NF-kB) proteins were analysed by western blot. Immunohistochemistry (Bax) and electron microscopy were done to assess apoptosis. RESULTS: The results showed reduction in the seizure score, percentage of kindled rats and neurological damage score in DMF treated rats. Pro-inflammatory cytokines concentrations were also decreased by DMF treatment. DMF downregulated the expression of inflammatory (NF-kB) and apoptotic (Bax, Caspase-3) genes and protein. DMF treatment increased the gene expression of Nrf2, HO-1, NQO1, Bcl-2 and protein expression of Nrf2 and Bcl2. CONCLUSION: DMF demonstrated anti-apoptotic, anti-inflammatory and anti-oxidative effect in hippocampus, which might be regulated by increased level of antioxidant response elements.