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PubMed1984

[Psoriasis therapy with fumaric acid and fumaric acid esters].

Fumaric acid may not be regarded as an antipsoriatic drug. Beneficial effects on psoriatic lesions may be explained by secondary changes such as the acidification of gastric juice in cases of anacidity or hypacidity . Monoethylfumarate exerts true antipsoriatic activities but is by far too toxic for clinical use. Experimental investigations have confirmed an inhibitory action of the above-mentioned fumarate on nucleic acid synthesis and protein synthesis of PHA-stimulated human lymphocytes.

DNA↗
PubMed2002

Topical calcipotriol plus oral fumaric acid is more effective and faster acting than oral fumaric acid monotherapy in the treatment of severe chronic plaque psoriasis vulgaris.

BACKGROUND: Calcipotriol is an established topical therapy for psoriasis vulgaris. OBJECTIVE: This study aimed to investigate whether the addition of calcipotriol to fumaric acid ester (FAE) monotherapy had an additive efficacy and an FAE-sparing effect in patients with severe plaque psoriasis. METHODS: This multicentre, randomised, double-blind, vehicle-controlled study included 143 patients for up to 13 weeks treatment. Group A received FAE tablets (Fumaderm) with an increasing daily dosage from 105 to 1,075 mg + ointment vehicle. Group B received FAE tablets + calcipotriol ointment (50 microg/g). Ointments were applied twice daily. Clinical response was assessed using percentage changes in the Psoriasis Area and Severity Index (PASI), from baseline to treatment end. RESULTS: The mean percentage change in the PASI was -76.1% in group B and -51.9% in group A, the difference between treatments was -24.2% (95% CI from -34.2 to -14.2%; p < 0.001). Group B responded more rapidly to treatment. Investigators' and patients' overall efficacy assessments were significantly more favourable for group B (p < or = 0.001). Group B was prescribed less FAE than group A. This difference was greatest at the last visit (mean daily dose 529 and 685 mg, respectively; p = 0.006). Overall adverse events in the two groups were similar. CONCLUSION: This study shows that the combination of calcipotriol and FAEs is significantly more effective and faster acting than FAE monotherapy in the treatment of severe plaque psoriasis. The combination has a slight FEA-sparing effect and therefore a superior benefit/risk ratio.

Administration, Oral↗
PubMed1999

Treatment of severe psoriasis with fumaric acid esters: scientific background and guidelines for therapeutic use. The German Fumaric Acid Ester Consensus Conference.

Fumaric acid ester (FAE) therapy has proved to be safe and effective in patients with severe psoriasis vulgaris. This treatment was introduced nearly 30 years ago, but is only now gaining renewed interest among dermatologists. FAE therapy is licensed in Germany and registration is pending in many European countries. Multicentre trials have confirmed the beneficial effect of FAE in psoriasis and have defined the spectrum of its adverse effects. Although the mode of action of FAEs in the treatment of psoriasis is not fully understood, recent experimental data point towards a skewing of the Th1-dominated T-cell response in psoriasis to a Th2-like pattern, and inhibition of proliferation of keratinocytes. This article reviews the experimental and clinical information on FAEs in psoriasis and provides guidelines for the clinical use of FAEs derived from a consensus meeting of leading experts.

Cytokines↗
PubMed1998

Investigation of the fumarate metabolism of the syntrophic propionate-oxidizing bacterium strain MPOB.

The growth of the syntrophic propionate-oxidizing bacterium strain MPOB in pure culture by fumarate disproportionation into carbon dioxide and succinate and by fumarate reduction with propionate, formate or hydrogen as electron donor was studied. The highest growth yield, 12.2 g dry cells/mol fumarate, was observed for growth by fumarate disproportionation. In the presence of hydrogen, formate or propionate, the growth yield was more than twice as low: 4.8, 4.6, and 5.2 g dry cells/mol fumarate, respectively. The location of enzymes that are involved in the electron transport chain during fumarate reduction in strain MPOB was analyzed. Fumarate reductase, succinate dehydrogenase, and ATPase were membrane-bound, while formate dehydrogenase and hydrogenase were loosely attached to the periplasmic side of the membrane. The cells contained cytochrome c, cytochrome b, menaquinone-6 and menaquinone-7 as possible electron carriers. Fumarate reduction with hydrogen in membranes of strain MPOB was inhibited by 2-(heptyl)-4-hydroxyquinoline-N-oxide (HOQNO). This inhibition, together with the activity of fumarate reductase with reduced 2,3-dimethyl-1,4-naphtoquinone (DMNH2) and the observation that cytochrome b of strain MPOB was oxidized by fumarate, suggested that menequinone and cytochrome b are involved in the electron transport during fumarate reduction in strain MPOB. The growth yields of fumarate reduction with hydrogen or formate as electron donor were similar to the growth yield of Wolinella succinogenes. Therefore, it can be assumed that strain MPOB gains the same amount of ATP from fumarate reduction as W. succinogenes, i. e. 0.7 mol ATP/mol fumarate. This value supports the hypothesis that syntrophic propionate-oxidizing bacteria have to invest two-thirds of an ATP via reversed electron transport in the succinate oxidation step during the oxidation of propionate. The same electron transport chain that is involved in fumarate reduction may operate in the reversed direction to drive the energetically unfavourable oxidation of succinate during syntrophic propionate oxidation since (1) cytochrome b was reduced by succinate and (2) succinate oxidation was similarly inhibited by HOQNO as fumarate reduction.

Adenosine Triphosphatases↗
PubMed2001

Generation of a proton potential by succinate dehydrogenase of Bacillus subtilis functioning as a fumarate reductase.

The membrane fraction of Bacillus subtilis catalyzes the reduction of fumarate to succinate by NADH. The activity is inhibited by low concentrations of 2-(heptyl)-4-hydroxyquinoline-N-oxide (HOQNO), an inhibitor of succinate: quinone reductase. In sdh or aro mutant strains, which lack succinate dehydrogenase or menaquinone, respectively, the activity of fumarate reduction by NADH was missing. In resting cells fumarate reduction required glycerol or glucose as the electron donor, which presumably supply NADH for fumarate reduction. Thus in the bacteria, fumarate reduction by NADH is catalyzed by an electron transport chain consisting of NADH dehydrogenase (NADH:menaquinone reductase), menaquinone, and succinate dehydrogenase operating in the reverse direction (menaquinol:fumarate reductase). Poor anaerobic growth of B. subtilis was observed when fumarate was present. The fumarate reduction catalyzed by the bacteria in the presence of glycerol or glucose was not inhibited by the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) or by membrane disruption, in contrast to succinate oxidation by O2. Fumarate reduction caused the uptake by the bacteria of the tetraphenyphosphonium cation (TPP+) which was released after fumarate had been consumed. TPP+ uptake was prevented by the presence of CCCP or HOQNO, but not by N,N'-dicyclohexylcarbodiimide, an inhibitor of ATP synthase. From the TPP+ uptake the electrochemical potential generated by fumarate reduction was calculated (Deltapsi = -132 mV) which was comparable to that generated by glucose oxidation with O2 (Deltapsi = -120 mV). The Deltapsi generated by fumarate reduction is suggested to stem from menaquinol:fumarate reductase functioning in a redox half-loop.

Bacillus subtilis↗
PubMedDate not supplied

The antipsoriatic dimethyl-fumarate suppresses interferon-gamma -induced ICAM-1 and HLA-DR expression on hyperproliferative keratinocytes. Quantification by a culture plate-directed APAAP-ELISA technique.

The derivatives of fumaric acid show antipsoriatic effects but details of the mechanism of action are largely unknown. The study focused on the effect of fumaric acid, dimethyl-fumarate, Zn-, Ca- and Mg-monoethyl-fumarate on the interferon-gamma (IFN-gamma)-induced expression of ICAM-1 and HLA-DR molecules on keratinocytes. Human hyperproliferative keratinocytes of the HaCaT cell line were exposed to IFN-gamma (10 U/ml) alone or in combination with fumaric acid and its derivatives for 48 hrs. The effect of fumarates was investigated semiquantitatively using the alkaline phosphatase-anti-alkaline phosphatase (APAAP) method. Subsequently, the effect of dimethyl-fumarate, the main component of "fumaric acid therapy", was evaluated quantitatively by means of an APAAP-ELISA technique. The semiquantitative evaluation revealed that in the micromolar dose range investigated only dimethyl-fumarate demonstrated substantial growth inhibition and down-regulation of the cell surface markers. In the quantitative evaluation, dimethyl-fumarate significantly (p</=0.05) suppressed the expression of ICAM-1 (84%) and HLA-DR (67%) on HaCaT keratinocytes at a subtoxic concentration of 4.0 microM as compared to untreated controls (100%). In contrast, concentrations of 4.0, 12 and 35 microM dimethyl-fumarate had no influence on the ICAM-1 and HLA-DR expression on IFN-gamma-exposed normal human epidermal keratinocytes in primary cultures. Thus, there is experimental evidence that dimethyl-fumarate may exert its antipsoriatic effect not only as an antiproliferative agent but also by down-regulation of ICAM-1 and HLA-DR molecules on hyperproliferative keratinocytes.

Cell Division↗
PubMed1998

Fumarate modulates bacterial flagellar rotation by lowering the free energy difference between the clockwise and counterclockwise states of the motor.

Switching flagellar rotation from one direction to another is an essential part of bacterial chemotaxis. Fumarate has been shown to possess the capacity to restore to flagella of cytoplasm-free, CheY-containing bacterial envelopes the ability to switch directions and to increase the probability of reversal in intact cells. Neither the target of fumarate action nor the mechanism of function is known. To distinguish between the two potential targets of fumarate, the response regulator CheY and the flagellar switch-motor complex, we compared flagellar rotation between isogenic strains that lacked CheY and had either low or high levels of fumarate. The difference in the fumarate levels was due to a deletion of the genes encoding the enzymes that synthesize and metabolize fumarate; succinate dehydrogenase and fumarase, respectively. The strains were in a gutted background (i.e. a background deleted for the cytoplasmic chemotaxis proteins and some of the receptors), and switching was achieved by carrying out the measurements at 2.5 degreesC, where it has been demonstrated that gutted cells switch spontaneously. The flagellar rotation of the strain with the highest level of fumarate was the most clockwise-biased and had the highest reversal frequency, indicating that fumarate is effective even in the absence of CheY. Fumarate reduced the free energy difference of the counterclockwise-to-clockwise transition and had no appreciable effect on the activation energy of this transition. Similar observations were made at room temperature, provided that intracellular CheY was present. In a wild-type background, both mutants made rings on semi-solid agar typical of normal chemotaxis. Taken together, the results suggest that the target of fumarate is the switch-motor complex, that fumarate acts by increasing the probability of the clockwise state, and that a fumarate level as low as that found in succinate dehydrogenase mutants is sufficient for normal chemotaxis.

Bacterial Proteins↗
PubMed1998

Deletion and site-directed mutagenesis of the Wolinella succinogenes fumarate reductase operon.

Wolinella succinogenes is known to grow at the expense of fumarate respiration with formate or sulfide as electron donor. A W. succinogenes mutant (delta frdCAB) lacking the fumarate reductase operon did not grow with fumarate as terminal electron acceptor and either formate or sulfide as electron donor. The delta frdCAB mutant grown with formate and nitrate did not contain fumarate reductase activity and did not catalyze electron transport from sulfide to fumarate, in contrast to the nitrate-grown wild-type strain. A mutant constructed by integration of frdCAB into the delta frdCAB mutant genome showed wild-type properties with respect to growth and enzyme activities. The frdC2 gene located downstream of the fumarate reductase operon frdCAB possibly encodes a diheme cytochrome b that is similar to FrdC (41% identical residues). The corresponding transcript differs from that of frdCAB. A delta frdC2 mutant showed wild-type properties with respect to growth and enzyme activities. Using site-directed mutagenesis, each of the four histidine residues that are predicted to serve as the axial heme ligands in FrdC (His44, His93, His143, and His182) was replaced by alanine or other residues. The resulting mutants did not grow with formate and fumarate and did not contain fumarate reductase activity, FrdA or FrdC when grown with formate and nitrate. In contrast, substitution of two histidine residues that are not considered heme ligands, yielded mutants (H114A and H120A) that grew with fumarate. It is concluded that FrdCAB is an obligatory component of fumarate respiration with formate and with sulfide in W. succinogenes. FrdC2 is not involved in fumarate respiration. Replacement of the putative heme ligands of FrdC prevents formation of a functional fumarate reductase.

Alanine↗
PubMed2000

Activity and properties of fumarate reductase in ruminal bacteria.

Fumarate-reducing bacteria were sought from the main ruminal bacteria. Fibrobacter succinogenes, Selenomonas ruminantium subsp. ruminantium, Selenomonas ruminantium subsp. lactilytica, and Veillonella parvula reduced fumarate by using H(2) as an electron donor. Ruminococcus albus, Prevotella ruminicola, and Anaerovibrio lipolytica consumed fumarate, although they did not oxidize H(2). Of these bacteria, V. parvula, two strains of Selenomonas, and F. succinogenes had a high capacity to reduce fumarate. In all the fumarate-reducing bacteria examined, fumarate reductase existed in the membrane fraction. Based on the activity per cell mass and the affinity of fumarate reductase to fumarate, these bacteria were divided into two groups, which corresponded to the capacity to use H(2): A group of bacteria with higher activity and affinity were able to use H(2) as an electron donor for fumarate reduction. The bacteria in this group should gain an advantage over the bacteria in another group in fumarate reduction in the rumen. Cellulose digestion by R. albus was improved by fumarate reduction by S. lactilytica as a result of an increased growth of R. albus, which may have been caused by the fact that S. lactilytica immediately consumed H(2) produced by R. albus. Thus fumarate reduction may play an important role in keeping a low partial pressure of H(2) in the rumen.

Journal Article↗
PubMed1998

How fumarase recycles after the malate --> fumarate reaction. Insights into the reaction mechanism.

Recycling of yeast fumarase to permit repetition of its reaction chemistry requires two proton transfers and two conformational changes, in pathways that are different in detail but thematically similar in the two directions. In the malate --> fumarate direction, simple anions such as acetate accelerate the fumarate-off step producing E(H(f)), a fumarate-specific isoform that retains the C3R-proton of malate. Fumarate specificity is shown with S-2,3-dicarboxyaziridine, which is competitive vs fumarate and noncompetitive with malate as substrate. The steady-state level of E(H(f)), based on Kii (S-2,3-dicarboxyaziridine), is increased by D2O and decreased by imidazole acting as a general acid for conversion of E(H(f)) to E(H(f))H. E(H(f))H is fumarate-specific as shown by the inhibition pattern with ClO4-. The pKa of this step is approximately 7.25 based on the pH dependence of Kii (ClO4-). A conformational change occurs next as shown by high sensitivity of k(cat) but not k(cat)/Km, to the microviscosogen, glycerol, and change to a nonspecific isoform, E(H(mf))H, probably the same species formed in the fumarate --> malate direction from malate-specific intermediates by a different conformational change. Malate enters the cycle by reaction with E(H(mf))H and returns to E(m)H x malate after a second conformational change. When fumarate-off is slow, as in low anion medium, malate itself becomes an activator of malate --> fumarate. This effect occurs with changes in inhibition patterns suggestive of the bypass of the slow E(f) --> E(mf) conversion in favor of direct formation of E(mf) when free fumarate is formed. 3-Nitro-2-hydroxypropionate, a strong inhibitor of fumarase [Porter, D. J. T., and Bright, H. J. (1980) J. Biol. Chem. 255, 4772-4780] in its carbanion form, is competitive with both malate and fumarate. Therefore, 3-nitro-2-hydroxypropionic acid interacts with E(H(mf))H and not with E(m) or E(f) isoforms. Occurrence of two different conformational changes in the recycling process suggests that the reaction chemistry employs a two-step mechanism. The specificity of inhibition for E(H(mf))H is consistent with the expected intermediate of a carbanion mechanism, E(H)H x carbanion-. The proton transfers and conformational changes of recycling occur in the same sequence that is expected for this reaction chemistry. Several examples of ligand-activated conformational changes are reported.

Animals↗
PubMed2002

Reconstitution of coupled fumarate respiration in liposomes by incorporating the electron transport enzymes isolated from Wolinella succinogenes.

Hydrogenase and fumarate reductase isolated from Wolinella succinogenes were incorporated into liposomes containing menaquinone. The two enzymes were found to be oriented solely to the outside of the resulting proteoliposomes. The proteoliposomes catalyzed fumarate reduction by H2 which generated an electrical proton potential (Delta(psi) = 0.19 V, negative inside) in the same direction as that generated by fumarate respiration in cells of W. succinogenes. The H+/e ratio brought about by fumarate reduction with H2 in proteoliposomes in the presence of valinomycin and external K+ was approximately 1. The same Delta(psi) and H+/e ratio was associated with the reduction of 2,3-dimethyl-1,4-naphthoquinone (DMN) by H2 in proteoliposomes containing menaquinone and hydrogenase with or without fumarate reductase. Proteoliposomes containing menaquinone and fumarate reductase with or without hydrogenase catalyzed fumarate reduction by DMNH2 which did not generate a Delta(psi). Incorporation of formate dehydrogenase together with fumarate reductase and menaquinone resulted in proteoliposomes catalyzing the reduction of fumarate or DMN by formate. Both reactions generated a Delta(psi) of 0.13 V (negative inside). The H+/e ratio of formate oxidation by menaquinone or DMN was close to 1. The results demonstrate for the first time that coupled fumarate respiration can be restored in liposomes using the well characterized electron transport enzymes isolated from W. succinogenes. The results support the view that Delta(psi) generation is coupled to menaquinone reduction by H2 or formate, but not to menaquinol oxidation by fumarate. Delta(psi) generation is probably caused by proton uptake from the cytoplasmic side of the membrane during menaquinone reduction, and by the coupled release of protons from H2 or formate oxidation on the periplasmic side. This mechanism is supported by the properties of two hydrogenase mutants of W. succinogenes which indicate that the site of quinone reduction is close to the cytoplasmic surface of the membrane.

Base Sequence↗
PubMed1973

Isolation and properties of fumarate reductase mutants of Escherichia coli.

Escherichia coli produces two enzymes which interconvert succinate and fumarate: succinate dehydrogenase, which is adapted to an oxidative role in the tricarboxylic acid cycle, and fumarate reductase, which catalyzes the reductive reaction more effectively and allows fumarate to function as an electron acceptor in anaerobic growth. A glycerol plus fumarate medium was devised for the selection of mutants (frd) lacking a functional fumarate reductase by virtue of their inability to use fumarate as an anaerobic electron acceptor. Most of the mutants isolated contained less than 1% of the parental fumarate reduction activity. Measurements of the fumarate reduction and succinate oxidation activities of parental strains and frd mutants after aerobic and anaerobic growth indicated that succinate dehydrogenase was completely repressed under anaerobic conditions, the assayable succinate oxidation activity being due to fumarate reductase acting reversibly. Fumarate reductase was almost completely repressed under aerobic conditions, although glucose relieved this repression to some extent. The mutations, presumably in the structural gene (frd) for fumarate reductase, were located at approximately 82 min on the E. coli chromosome by conjugation and transduction with phage P1. frd is very close to the ampA locus, and the order of markers in this region was established as ampA-frd-purA.

Anaerobiosis↗