citraconic-acid and Inflammation

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.. 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.. 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.. 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.

Topics: Animals; Astrocytes; Coculture Techniques; Connexin 43; Dimethyl Fumarate; Inflammation; Microglia; Rats

Although the immunomodulatory and cytoprotective properties of itaconate have been studied extensively, it is not known whether its naturally occurring isomers mesaconate and citraconate have similar properties. Here, we show that itaconate is partially converted to mesaconate intracellularly and that mesaconate accumulation in macrophage activation depends on prior itaconate synthesis. When added to human cells in supraphysiological concentrations, all three isomers reduce lactate levels, whereas itaconate is the strongest succinate dehydrogenase (SDH) inhibitor. In cells infected with influenza A virus (IAV), all three isomers profoundly alter amino acid metabolism, modulate cytokine/chemokine release and reduce interferon signalling, oxidative stress and the release of viral particles. Of the three isomers, citraconate is the strongest electrophile and nuclear factor-erythroid 2-related factor 2 (NRF2) agonist. Only citraconate inhibits catalysis of itaconate by cis-aconitate decarboxylase (ACOD1), probably by competitive binding to the substrate-binding site. These results reveal mesaconate and citraconate as immunomodulatory, anti-oxidative and antiviral compounds, and citraconate as the first naturally occurring ACOD1 inhibitor.

Topics: Antiviral Agents; Carboxy-Lyases; Catalysis; Fumarates; Humans; Inflammation; Interferons; Macrophages; Maleates; Oxidative Stress

Sepsis is a potentially fatal illness that can lead to impairment of multiple organs such as liver. The condition is deeply associated with oxidative stress and inflammation. Monomethyl fumarate (MMF) has manifested antioxidant and immunomodulatory properties. The aim of current study was to evaluate protective effects of MMF in sepsis-induced hepatic dysfunction.. Sepsis was induced by cecal ligation and puncture (CLP). Wistar rats were assigned to one of sham, CLP, CLP + dexamethasone (as positive control of inflammation) and CLP + MMF groups. Levels of serum IL-1β, IL-6, IL-10, AST, ALT and γ‑GT were quantified. Furthermore, Hepatic levels of GSH and MDA and mRNA expression of TNF and NFKBIA along with hepatic protein level of TLR-4 were assessed. Also, histopathological study of liver was carried out to evaluate hepatic injuries.. Septic rats demonstrated risen levels of IL-1β, IL-6, IL-10, AST, ALT and γ‑GT, while treatment with dexamethasone or MMF attenuated these levels. Moreover, enhancements in protein level of TLR-4 and mRNA levels of TNF and NFKBIA were observed in CLP rats. These elevations were mitigated in CLP-induced rats that were treated with either dexamethasone or MMF. Treatment with dexamethasone or MMF also shifted sepsis-induced disturbance in the levels of GSH and MDA towards sham levels. Hepato-protective effects of dexamethasone and MMF were further confirmed by histopathological observations.. Our findings imply that MMF alleviates sepsis-induced hepatic dysfunction by mitigating the inflammatory and oxidative state and this effect is at least partly mediated by the inhibition of TLR-4/NF-κB signalling pathway.

Topics: Animals; Antioxidants; Dexamethasone; Disease Models, Animal; Fumarates; Inflammation; Liver Diseases; Male; Maleates; NF-kappa B; NF-KappaB Inhibitor alpha; Oxidative Stress; Rats; Rats, Wistar; RNA, Messenger; Sepsis; Signal Transduction; Toll-Like Receptor 4

HIV-associated neurocognitive disorders (HAND) affect about 50% of infected patients despite combined antiretroviral therapy (cART). Ongoing compartmentalized inflammation mediated by microglia which are activated by HIV-infected monocytes has been postulated to contribute to neurotoxicity independent from viral replication. Here, we investigated effects of teriflunomide and monomethylfumarate on monocyte/microglial activation and neurotoxicity. Human monocytoid cells (U937) transduced with a minimal HIV-Vector were co-cultured with human microglial cells (HMC3). Secretion of pro-inflammatory/neurotoxic cytokines (CXCL10, CCL5, and CCL2: p < 0.001; IL-6: p < 0.01) by co-cultures was strongly increased compared to microglia in contact with HIV-particles alone. Upon treatment with teriflunomide, cytokine secretion was decreased (CXCL10, 3-fold; CCL2, 2.5-fold; IL-6, 2.2-fold; p < 0.001) and monomethylfumarate treatment led to 2.9-fold lower CXCL10 secretion (p < 0.001). Reduced toxicity of co-culture conditioned media on human fetal neurons by teriflunomide (29%, p < 0.01) and monomethylfumarate (27%, p < 0.05) indicated functional relevance. Modulation of innate immune functions by teriflunomide and monomethylfumarate may target neurotoxic inflammation in the context of HAND.

Topics: Coculture Techniques; Crotonates; Culture Media, Conditioned; Dermatologic Agents; Dose-Response Relationship, Drug; Fetus; Fumarates; HIV-1; Humans; Hydroxybutyrates; Inflammation; Inflammation Mediators; Maleates; Microglia; Monocytes; Nitriles; Toluidines; U937 Cells