References of "Deby-Dupont, Ginette"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailEffect of different kinds of anoxia/reoxygenation on the mitochondrial function and the free radicals production of cultured primary equine skeletal myoblasts.
Ceusters, Justine ULg; Mouithys-Mickalad, Ange ULg; Franck, Thierry ULg et al

in Research in Veterinary Science (2013), 95

Horses are outstanding athletes, performing in many different disciplines involving different kinds of efforts and metabolic responses. Depending on exercise intensity, their skeletal muscle oxygenation ... [more ▼]

Horses are outstanding athletes, performing in many different disciplines involving different kinds of efforts and metabolic responses. Depending on exercise intensity, their skeletal muscle oxygenation decreases, and the reperfusion at cessation of the exercise can cause excessive production of free radicals. This study on cultured primary equine myoblasts investigated the effect of different kinds of anoxia/reoxygenation (A/R) on routine respiration, mitochondrial complex I specific activity and free radicals production. Our data revealed that short cycles of A/R caused a decrease of all the parameters, opposite to what a single long period of anoxia did. A preconditioning-like effect could explain our first pattern of results whereas mild uncoupling could be more appropriate for the second one. Anyway, it seems that mitochondrial complex I could play a major role in the regulation of the balance between metabolic and antioxidant protection of the muscular function of athletic horses. [less ▲]

Detailed reference viewed: 18 (3 ULg)
Full Text
See detailA water-soluble salt of curcumin (NDS27) inhibits myeloperoxidase and NADPH oxidase activities, two major enzymes of neutrophils.
Derochette, Sandrine ULg; Mouithys-Mickalad, Ange ULg; Deby-Dupont, Ginette et al

Poster (2013, September 11)

Neutrophils (PMNs) produce reactive oxygen species (ROS) to kill pathogenic agents. After appropriate stimulation, leading to the activation of protein kinase C (PKC), the cytosolic subunits of the NADPH ... [more ▼]

Neutrophils (PMNs) produce reactive oxygen species (ROS) to kill pathogenic agents. After appropriate stimulation, leading to the activation of protein kinase C (PKC), the cytosolic subunits of the NADPH oxidase (Nox2) are phosphorylated and translocated to the membrane flavocytochrome b558, forming the active enzyme which produces superoxide anion (O2●-). From O2●- derives H2O2 used by the PMNs myeloperoxidase (MPO) to form strong oxidant species. Many human and animal pathologies with fatal issue are associated with uncontrolled activation of PMNs. The modulation of enzymes implied in ROS production is thus a primary target to manage excessive inflammatory events. For this purpose, we evaluated the effects of NDS27, a water-soluble salt of curcumin combined with hydroxypropyl-β-cyclodextrin, on the activities of PKC, Nox2 and MPO. PKC activation was determined by western blotting with specific antibodies against phosphorylated PKC in extracts from PMNs after their incubation or not with NDS27. A cell-free assay was used to evaluate the effect of NDS27 before or after the assembly of Nox2 subunits. MPO activity was tested by the SIEFED technique in which NDS27 was pre-incubated with the enzyme and discarded before its activity measurement. An inhibition of PKC phosphorylation and Nox2 activity were observed at respectively 10-4 and 10-5 M of NDS27. The Nox2 inhibition was more pronounced when NDS27 was added before the assembly stimulation, suggesting a direct action of NDS27 on the subunits translocation. NDS27 also dose-dependently decreased the activity of MPO (21 % at 10-5 M), indicating an interaction with the enzyme structure. Our results demonstrated that NDS27 is a potent inhibitor of the two major enzymes responsible for ROS production in PMNs, and also acts on the activation cascade of Nox2. The modulatory effect of NDS27 towards the oxidant activity of PMNs opens therapeutic perspectives to control pathologies with excessive inflammatory reactions. [less ▲]

Detailed reference viewed: 34 (5 ULg)
Full Text
Peer Reviewed
See detailIntra- and extracellular antioxidant capacities of the new water-soluble form of curcumin (NDS27) on stimulated neutrophils and HL-60 cells
Derochette, Sandrine ULg; Franck, Thierry ULg; Mouithys-Mickalad, Ange ULg et al

in Chemico-Biological Interactions (2013), 201(1-3), 49-57

Phagocytic cells, especially neutrophils (PMNs) are specialized in the production of reactive oxygen species (ROS) to kill pathogenic agents, but an excessive ROS production is associated with tissue ... [more ▼]

Phagocytic cells, especially neutrophils (PMNs) are specialized in the production of reactive oxygen species (ROS) to kill pathogenic agents, but an excessive ROS production is associated with tissue damages and inflammatory diseases. Phagocytes are thus prime therapeutic targets to control inflammatory events associated to ROS production. Nowadays, there is a growing interest for the use of polyphenols to modulate the inflammatory response. The aim of this work was to study the antioxidant effect of NDS27, a highly water-soluble form of the polyphenolic molecule curcumin, on in vitro stimulated equine PMNs and human promyelocytic leukemia cells (HL-60). NDS27 was either pre-incubated with cells and eliminated before their activation (intracellular effect) or let in the medium (extracellular effect). Our results indicate that NDS27 significantly and dose-dependently (10 6 M–10 4 M) inhibited the ROS production in both cell types without affecting their viability. NDS27 was able to cross and interact with cell membrane, especially for HL-60 cells, while we observed a better intracellular antioxidant effect with PMNs. The activity of myeloperoxidase (MPO) released by PMNs and HL-60 cells, was decreased by NDS27, but more efficiently for PMNs. These results suggested that the greater efficiency of NDS27 in PMNs is due to an inhibitory effect on cells which are more mature for ROS production, probably by targeting the enzymes implied in respiratory burst like MPO. The modulatory effect of NDS27 on the oxidant activity of cells involved in immune and inflammatory responses opens perspectives for a therapeutic control of pathologies with excessive inflammatory reactions. [less ▲]

Detailed reference viewed: 26 (14 ULg)
Full Text
Peer Reviewed
See detailCurcumin and resveratrol act by different ways on NADPH oxidase activity and reactive oxygen species produced by equine neutrophils
Derochette, Sandrine ULg; Franck, Thierry ULg; Mouithys-Mickalad, Ange ULg et al

in Chemico-Biological Interactions (2013), 206

In neutrophils (PMNs), superoxide anion (O2●-), the first reactive oxygen species (ROS) produced to kill pathogenic agents, is generated by NADPH oxidase, an enzymatic complex formed by the translocation ... [more ▼]

In neutrophils (PMNs), superoxide anion (O2●-), the first reactive oxygen species (ROS) produced to kill pathogenic agents, is generated by NADPH oxidase, an enzymatic complex formed by the translocation of cytosolic subunits to the membrane flavocytochrome b558. In horses, excessive activation of PMNs is often associated with deadly pathologies and the modulation of their ROS production by acting on NADPH oxidase is a prime target to manage inflammation. We developed a cell-free assay to measure the activity of equine NADPH oxidase assembled in vitro, in order to test the effects of natural or synthetic compounds on the enzyme activity or assembly. The cell-free assay was validated with diphenyleneiodonium chloride and Gp91ds-tat, two inhibitors largely described for human NADPH oxidase. The anti-oxidant effects of curcumin and resveratrol at final concentration ranging from 10-4 to 10-6 M were studied on whole cells by chemiluminescence (CL) and by cell-free assay, in which the molecule was added before or after the enzyme assembly. The CL assay demonstrated that curcumin efficiently inhibited the O2●- production and easily entered into PMNs or interacted with their membrane. Cell-free assay showed that curcumin acted on the reconstitution of NADPH oxidase even at 10-5 M, while resveratrol appeared to be an O2●- scavenger rather than an inhibitor of NADPH oxidase activity, since it acted from outside the cell in CL and after the complex assembly in cell-free assay. By acting directly on NADPH oxidase, curcumin should be a good candidate for the treatment of acute or inflammatory diseases involving an excessive ROS production. [less ▲]

Detailed reference viewed: 36 (7 ULg)
Full Text
Peer Reviewed
See detailEffect of myeloperoxidase and anoxia/reoxygenation on mitochondrial respiratory function of cultured primary equine skeletal myoblasts.
Ceusters, Justine ULg; Mouithys-Mickalad, Ange ULg; Franck, Thierry ULg et al

in Mitochondrion (2013), 13(5),

Horses are particularly sensitive to excessive inflammatory reaction where myeloperoxidase, a marker of inflammation, may contribute to mitochondrial dysfunctions. This study investigated the interaction ... [more ▼]

Horses are particularly sensitive to excessive inflammatory reaction where myeloperoxidase, a marker of inflammation, may contribute to mitochondrial dysfunctions. This study investigated the interaction between myeloperoxidase and cultured primary equine skeletal myoblasts, particularly its effect on mitochondrial respiration combined or not with anoxia followed by reoxygenation (AR). We showed that active myeloperoxidase entered into the cells, interacted with mitochondria and decreased routine and maximal respirations. When combined with AR, myeloperoxidase caused a further decrease of these respiratory parameters while the leak increased. Our results indicate that myeloperoxidase amplifies the mitochondrial damages initiated by AR phenomenon and alters the mitochondrial function. [less ▲]

Detailed reference viewed: 27 (11 ULg)
Full Text
Peer Reviewed
See detailDifferentiation between stoichiometric and anticatalytic antioxidant properties of benzoic acid analogues: A structure/redox potential relationship study.
Franck, Thierry ULg; Mouithys-Mickalad, Ange ULg; Robert, Thierry ULg et al

in Chemico-biological interactions (2013), 206(2), 194-203

We investigated the antioxidant activities of some phenolic acid derivatives on a cell free system and on cellular and enzymatic models involved in inflammation. The stoichiometric antioxidant activities ... [more ▼]

We investigated the antioxidant activities of some phenolic acid derivatives on a cell free system and on cellular and enzymatic models involved in inflammation. The stoichiometric antioxidant activities of phenolic acid derivatives were studied by measuring their capacity to scavenge the radical cation 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+) and reactive oxygen species (ROS) produced by stimulated neutrophils. The anticatalytic antioxidant capacity of the molecules was evaluated on the activity of myeloperoxidase (MPO), an oxidant enzyme present in and released by the primary granules of neutrophils. The ROS produced by PMA-stimulated neutrophils were measured by lucigenin-enhanced chemiluminescence (CL) and the potential interaction of the molecules with MPO was investigated without interferences due to medium by Specific Immuno-Extraction Followed by Enzyme Detection (SIEFED). The antioxidant activities of the phenolic compounds were correlated to their redox potentials measured by differential pulse voltammetry (DPV), and discussed in relation to their molecular structure. The ability of the phenolic molecules to scavenge ABTS radicals and ROS derived from neutrophils was inversely correlated to their increased redox potential. The number of hydroxyl groups (three) and their position (catechol) were essential for their efficacy as stoichiometric antioxidants or scavengers. On MPO activity, the inhibitory capacity of the molecules was not really correlated with their redox potential. Likewise, for the inhibition of MPO activity the number of OH groups and mainly the elongation of the carboxylic group were essential, probably by facilitating the interaction with the active site or the structure of the enzyme. The redox potential measurement, combined with ABTS and CL techniques, seems to be a good technique to select stoichiometric antioxidants but not anticatalytic ones, as seen for MPO, what rather involves a direct interaction with the enzyme. [less ▲]

Detailed reference viewed: 15 (3 ULg)
Full Text
Peer Reviewed
See detailEffects of diazoxide, benzothiadiazine and benzopyrane derivatives on mitochondrial proton and electron leaks of cardiomyocytes (H9C2 cell line).
Mouithys-Mickalad, Ange ULg; Ceusters, Justine ULg; Charef, M et al

Poster (2013)

Background: Mitochondria are double membrane- organelles that play a central role in cellular metabolism, calcium homeostasis and redox signaling. They have been also considered as main producers of ... [more ▼]

Background: Mitochondria are double membrane- organelles that play a central role in cellular metabolism, calcium homeostasis and redox signaling. They have been also considered as main producers of adenosine triphosphate (ATP) and reactive oxygen species (ROS). In many cancer cells those organelles become dysfunctional leading to a shift of energy metabolism from oxidative phosphorylation to active glycolysis and an increase of ROS generation. According to Warberg’ theory, cancer damage might occur at the mitochondrial level, affecting tiny structures within each cell implicated in the energy production through ATP. New insight is that mitochondria might be a good therapeutic target for metabolic syndromes, ischemia/reperfusion injury and organs transplantation. Therefore, search for novel molecules able to keep mitochondria functional are of relevant interest. Methodology: Cardiomyocytes (H9C2 cells) were from ATCC (USA) and grown till confluence. The basal cellular respiratory rate, proton and electron leaks as well as ATP production were measured with the High Resolution Oxygraphy (Oroboros, Austria). All compounds: diazoxide (DIAZ), diazoxide –related analogs (1: BPDZ-259, 2: BPDZ-444), and benzopyran derivatives (3: BPDZ-490, 4: BPDZ-711) were tested at final concentration of 10-5 M, except when specified and compared to control samples (cells with or without DMSO). Results and conclusion: The basal respiratory rate of H9C2 cells (5x106/mL) was changed depending on the chemical structure of the tested compounds: e.g. compound 3 strongly enhanced the routine respiration, while 4 displayed a marked lowering effect. In contrast, the addition of similar concentration of benzothiadiazin derivatives (1, 2) had no effect on routine respiration but also on the other respiratory parameters such as oligomycin-induced leak and ATP production. Similar profile was obtained with the reference molecule: diazoxide. Overall, our findings indicate that both diazoxide-like analogues (1 and 2) and diazoxide were without significant effect on basal respiration, ATP production, even on maximal respiration. Interestingly, two derivatives show opposite effects: compound 3 behaves as a uncoupling agent and the other one (4) exhibits a real lowering effect on respiration but that was reversible. The latter effect might be of interest if this kind of molecules could be used for further use as an agent for organ conservation during transplantation. Our results also demonstrate that diazoxide, a well-known Mito-KATP opener, did not exert its effect beside of clinical situation like ischemia/reperfusion injury. [less ▲]

Detailed reference viewed: 15 (0 ULg)
Full Text
See detailDoes the new water-soluble form of curcumin(NDS27) inhibit the oxidant response of stimulated neutrophils and HL-60 cells?
Derochette, Sandrine ULg; Franck, Thierry ULg; Deby-Dupont, Ginette et al

Poster (2012, September 07)

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) and the release of an oxidant enzyme, myeloperoxidase (MPO), to kill pathologic ... [more ▼]

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) and the release of an oxidant enzyme, myeloperoxidase (MPO), to kill pathologic agents. But, an excessive stimulation of PMNs is associated with development of inflammatory diseases. Neutrophils are prime targets to control inflammatory events and the therapeutic use of polyphenols is proposed to lower oxidative stress. The aim of this work was to study antioxidant effect of NDS27, a water-soluble form of curcumin, on stimulated equine PMNs and human promyelocytic leukemia cells (HL-60) which are less differenciated. 2',7'-Dichlorofluorescin diacetate and lucigenin were used to measure ROS production by activated HL-60 cells or PMNs. NDS27 (10-6 to 10-4 M) was pre-incubated with cells and eliminated before their activation to study its intracellular effects on ROS production. The effect of NDS27 on MPO activity released by the cells was determined by SIEFED. Likewise, the ability of NDS27 to enter into the cells was checked by HPLC on the cellular extracts.NDS27 significantly and dose-dependently inhibited the ROS production in both cell types without affecting their viability. Its intracellular effect showed higher efficiency for PMNs while its interaction with HL-60 cells remained better. The activity of MPO released by PMNs and HL-60 cells was decreased by NDS27 with a more efficient effect for PMNs. Our findings suggest that the greater efficiency of NDS27 in mature PMNs is not due to a better membrane permeability or a better interaction between membrane and NDS27, but rather to an inhibitory effect on the ROS production by the more mature cells, probably by targeting the enzymes implied in respiratory burst like MPO and NADPH oxidase. The modulatory effect of NDS27 towards oxidant activity of cells involved in immune and inflammatory response opens therapeutic perspectives to control pathologies with excessive inflammatory reactions. [less ▲]

Detailed reference viewed: 25 (5 ULg)
Full Text
See detailPossible intracellular effect of the new water-soluble form of curcumin (NDS27) on the oxidant response of stimulated neutrophils
Derochette, Sandrine ULg; Mouithys-Mickalad, Ange ULg; Deby-Dupont, Ginette et al

Poster (2012, April 18)

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) to kill pathologic agents. But, an excessive ROS production, called “oxidative ... [more ▼]

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) to kill pathologic agents. But, an excessive ROS production, called “oxidative stress” is associated with tissue damages and development of chronic or acute inflammatory diseases. PMNs are prime therapeutic targets to control inflammatory events associated to ROS production. Nowadays, there is a growing interest for the use of polyphenolic molecules to modulate the inflammatory response. The aim of this work was to study the antioxidant effect of NDS27 (1), a new highly water-soluble form of the polyphenolic molecule curcumin, on in vitro stimulated equine PMNs. NDS27 (10-6 to 10-4 M) was pre-incubated with cells and eliminated before their activation. The ability of NDS27 to enter into the cells was checked by HPLC from the cellular extracts. The intracellular ROS production by phorbol myristate acetate (PMA) stimulated PMNs was measured by fluorescence using 2’,7’-dichlorofluorescin diacetate. Lucigenin dependent chemiluminescence was used to measure extracellular ROS production. Additionally, the effect of NDS27 was tested on the activity of myeloperoxidase (MPO), a hemic enzyme contributing to the oxidant response of neutrophils. The activity of the released MPO by cytochalazine B (CB) and N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulated PMNs was measured by SIEFED (“Specific Immunologic Extraction Followed by Enzymatic Detection”) (2). The HPLC results showed that NDS27 enters into PMNs and interacts with their membrane. NDS27 significantly and dose-dependently inhibited the ROS production in neutrophils without affecting their viability. Likewise, the activity of MPO released by PMNs was lowered by NDS27. Overall, our findings demonstrate that the membrane of neutrophils is permeable to NDS27 or interacts with the drug, suggesting that its inhibitory effect on ROS production is mainly associated to an intracellular effect probably by acting on the enzymes implied in respiratory burst like NADPH oxidase and MPO. The modulatory effect of NDS27 towards the oxidant activity of cells involved in immune and inflammatory response open therapeutic perspectives to control equine or human pathologies with excessive inflammatory reactions. 1. Neven et al. 2011, Patent Application Publication: US2011/0257126 A1 2. Serteyn et al. 2005, European Patent Specification : EP1711817 B1 [less ▲]

Detailed reference viewed: 30 (4 ULg)
Full Text
Peer Reviewed
See detailAssessment of reactive oxygen species production in cultured equine skeletal myoblasts in response to conditions of anoxia followed by reoxygenation with or without exposure to peroxidases.
Ceusters, Justine ULg; Mouithys-Mickalad, Ange ULg; de la Rebière de Pouyade, Geoffroy ULg et al

in American Journal of Veterinary Research (2012), 73(3), 426-434

Objective—To culture equine myoblasts from muscle microbiopsy specimens, examine myoblast production of reactive oxygen species (ROS) in conditions of anoxia followed by reoxygenation, and assess the ... [more ▼]

Objective—To culture equine myoblasts from muscle microbiopsy specimens, examine myoblast production of reactive oxygen species (ROS) in conditions of anoxia followed by reoxygenation, and assess the effects of horseradish peroxidase (HRP) and myeloperoxidase (MPO) on ROS production. Animals—5 healthy horses (5 to 15 years old). Procedures—Equine skeletal myoblast cultures were derived from 1 or 2 microbiopsy specimens obtained from a triceps brachii muscle of each horse. Cultured myoblasts were exposed to conditions of anoxia followed by reoxygenation or to conditions of normoxia (control cells). Cell production of ROS in the presence or absence of HRP or MPO was assessed by use of a gas chromatography method, after which cells were treated with a 3,3′-diaminobenzidine chromogen solution to detect peroxidase binding. Results—Equine skeletal myoblasts were successfully cultured from microbiopsy specimens. In response to anoxia and reoxygenation, ROS production of myoblasts increased by 71%, compared with that of control cells. When experiments were performed in the presence of HRP or MPO, ROS production in myoblasts exposed to anoxia and reoxygenation was increased by 228% and 183%, respectively, compared with findings for control cells. Chromogen reaction revealed a close adherence of peroxidases to cells, even after several washes. Conclusions and Clinical Relevance—Results indicated that equine skeletal myoblast cultures can be generated from muscle microbiopsy specimens. Anoxia-reoxygenation– treated myoblasts produced ROS, and production was enhanced in the presence of peroxidases. This experimental model could be used to study the damaging effect of exercise on muscles in athletic horses. [less ▲]

Detailed reference viewed: 54 (27 ULg)
Full Text
Peer Reviewed
See detailPolyphenol Content and Modulatory Activities of Some Tropical Dietary Plant Extracts on the Oxidant Activities of Neutrophils and Myeloperoxidase
Tsumbu, César Ndele ULg; Deby-Dupont, Ginette; Tits, Monique ULg et al

in International Journal of Molecular Sciences (2012), 13(1), 628-650

Detailed reference viewed: 64 (22 ULg)
Full Text
Peer Reviewed
See detailAntioxidant and Antiradical Activities of Manihot esculenta Crantz (Euphorbiaceae) Leaves and Other Selected Tropical Green Vegetables Investigated on Lipoperoxidation and Phorbol-12-myristate-13-acetate (PMA) Activated Monocytes
Tsumbu, César Ndele ULg; Deby-Dupont, Ginette; Tits, Monique ULg et al

in Nutrients (2011), 3(9), 818-838

Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae), Manihot esculenta Crantz (Euphorbiaceae) and Pteridium aquilinum (Dennstaedtiaceae) leaves are currently consumed as vegetables by ... [more ▼]

Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae), Manihot esculenta Crantz (Euphorbiaceae) and Pteridium aquilinum (Dennstaedtiaceae) leaves are currently consumed as vegetables by migrants from sub-Saharan Africa living in Western Europe and by the people in the origin countries, where these plants are also used in the folk medicine. Manihot leaves are also eaten in Latin America and some Asian countries. This work investigated the capacity of aqueous extracts prepared from those vegetables to inhibit the peroxidation of a linoleic acid emulsion. Short chain, volatile C-compounds as markers of advanced lipid peroxidation were measured by gas chromatography by following the ethylene production. The generation of lipid hydroperoxides, was monitored by spectroscopy using N-N′-dimethyl-p-phenylene-diamine (DMPD). The formation of intermediate peroxyl, and other free radicals, at the initiation of the lipid peroxidation was investigated by electron spin resonance, using α-(4-pyridyl-1-oxide)-N-tert-butylnitrone as spin trap agent. The ability of the extracts to decrease the cellular production of reactive oxygen species (ROS) in “inflammation like” conditions was studied by fluorescence technique using 2′,7′-dichlorofluorescine-diacetate as fluorogenic probe, in a cell model of human monocytes (HL-60 cells) activated with phorbol ester. Overall the extracts displayed efficient concentration-dependent inhibitory effects. Their total polyphenol and flavonoid content was determined by classic colorimetric methods. An HPLC-UV/DAD analysis has clearly identified the presence of some polyphenolic compounds, which explains at least partially the inhibitions observed in our models. The role of these plants in the folk medicine by sub-Saharan peoples as well as in the prevention of oxidative stress and ROS related diseases requires further consideration. [less ▲]

Detailed reference viewed: 216 (9 ULg)
Peer Reviewed
See detailSpecific Immuno Extraction Followed by Enzymatic Detection (SIEFED), a new tool to measure active myeloperoxidase in complex media and to screen potential inhibitors of this enzyme.
Serteyn, Didier ULg; Mouithys-Mickalad, Ange ULg; Deby-Dupont, Ginette et al

in The 7th International Human Peroxidase Meeting, 22-25 May 2011, Brussels (2011, May 25)

A method called SIEFED (“Specific Immuno Extraction Followed by Enzymatic Detection”) was developed for the specific measurement of myeloperoxidase (MPO) activity without interference of the sample medium ... [more ▼]

A method called SIEFED (“Specific Immuno Extraction Followed by Enzymatic Detection”) was developed for the specific measurement of myeloperoxidase (MPO) activity without interference of the sample medium. In this method, MPO is first extracted out of aqueous or biological samples by its capture by immobilized anti-MPO antibodies. A washing step then allows to eliminate the solution or biological fluid with interfering materials (proteins, lipids, reducing or oxidizing molecules, ...) and in a last step the activity of MPO bound to its antibodies is measured by using a sensitive detection system containing a fluorogenic substrate, hydrogen peroxide and nitrite as reaction enhancer. SIEFED is a method of choice to measure easily, quantitatively, and specifically the active part of MPO present in biological samples or complex media. Results obtained with this technique applied to biological samples emphasize the importance to distinguish the total MPO concentration of a sample obtained by ELISA from the active part of MPO, which is the real witness of the oxidant potential of the enzyme. SIEFED is also a powerful tool to study compounds or natural extracts that could have an inhibitory effect on the activity of MPO. Since the potential inhibitor is first incubated with the enzyme solution, and further eliminated by washing after the immunocapture of MPO, the tested compound or extract cannot interfere with the chromogenic substrate used to measure the activity of MPO or with products derived from the enzyme activity. Thus, an inhibitory effect could only be attributed to a direct interaction of the tested compound with the enzyme, either on the active site or another key position of the structure. In conclusion, the SIEFED technique opens new perspectives to study pathologies in which the release of active MPO is relevant and to select interesting compounds or extracts able to modulate the MPO activity. [less ▲]

Detailed reference viewed: 64 (10 ULg)
Peer Reviewed
See detailEffect of benzoic acid analogs on myeloperoxidase activity measured by a new technique to study their direct interaction with the enzyme.
Franck, Thierry ULg; Mazloum, Ali; Mouithys-Mickalad, Ange ULg et al

Poster (2011, May)

Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human ... [more ▼]

Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human MPO measured by SIEFED (“Specific Immunologic Extraction Followed by Enzymatic Detection”), an original method that consists of incubation of the compound with MPO, followed by capture of the enzyme by specific antibodies, washing (elimination of the compounds) and enzymatic detection of the immunocaptured enzyme. The compounds tested at 10-4, 10-5 and 10-6 M were studied in terms of structure activity relationship. Gallic acid (3,4,5-trihydroxybenzoic acid) with 3 hydroxyl groups had an important dose dependent inhibitory effect on MPO activity. Other molecules with less or without hydroxyl groups [3,4-dihydroxybenzoic acid, 2-hydroxybenzoic acid (salicylic acid) and benzoic acid] had rather an activator effect at 10-5 and 10-6 M. 2,4,6-Trihydroxybenzoic acid, with two hydroxyl groups adjacent to the carboxyl group, had a less efficient inhibitory effect. Caffeic acid (3,4-dihydroxycinnamic acid) with a propenoic acid group presented a dose dependent inhibitory effect on MPO activity contrary to its analog 3,4-dihydroxybenzoic acid. The esterification of the carboxyl group of gallic acid to obtain propyl gallate induced an activation of MPO at 10-5 and 10-6 M. Finally, the substitution of one or two hydroxyl groups by methoxyl ones (ferulic and syringic acids) decreased the efficiency of the molecules on the enzyme inhibition. The SIEFED technique appears as an innovative pharmacological tool to study the direct interaction of compounds with MPO. Number and position of hydroxyl groups and the extension of the carboxyl group of benzoic acid play a crucial role in the inhibition of MPO activity probably by facilitating the interaction with the active site or another elements of the enzyme structure. [less ▲]

Detailed reference viewed: 34 (3 ULg)
Full Text
Peer Reviewed
See detailModulating effects of acepromazine on the reactive oxygen species production by stimulated equine neutrophils
Sandersen, Charlotte ULg; Mouithys-Mickalad, Ange ULg; de la Rebière de Pouyade, Geoffroy ULg et al

in Veterinary Anaesthesia & Analgesia (2011), 38

To investigate the effect of acepromazine (ACP) on reactive oxygen species (ROS) production by stimulated equine neutrophils.

Detailed reference viewed: 19 (5 ULg)
Full Text
Peer Reviewed
See detailProduction of free radicals and oxygen consumption by primary equine endothelial cells during anoxia-reoxygenation.
de la Rebière de Pouyade, Geoffroy ULg; Salciccia, Alexandra ULg; Ceusters, Justine ULg et al

in Open Biochemistry Journal (The) (2011), 5

The endothelium plays an active role in ischemia/reperfusion injuries. Herein, we report the effect of a single or successive cycles of anoxia/reoxygenation (A/R) on the mitochondrial respiratory function ... [more ▼]

The endothelium plays an active role in ischemia/reperfusion injuries. Herein, we report the effect of a single or successive cycles of anoxia/reoxygenation (A/R) on the mitochondrial respiratory function of equine endothelial cells (cultured from carotids) monitored by high resolution oxymetry, and on their production of reactive oxygen species (ROS). ROS were measured by electron paramagnetic resonance (ESR) using POBN and DMPO spin traps, and by gas chromatography (GC) of ethylene released by ROS-induced alpha-keto-gamma-(methylthio)butyric acid (KMB) oxidation. The oxygen consumption significantly decreased with the number of A/R cycles, and POBN-ESR spectra were specific of adducts formed in the cells from superoxide anion. After a one-hour A/R cycle, high intensity DMPO-ESR spectra were observed and assigned to superoxide anion trapping; the GC results confirmed an important production of ROS compared to normoxic cells. These results show that A/R induces mitochondrial alterations in endothelial cells, and strongly stimulates their oxidative activity as demonstrated by ESR and GC methods. [less ▲]

Detailed reference viewed: 28 (6 ULg)
Full Text
Peer Reviewed
See detailModulatory activities of Agelanthus dodoneifolius (Loranthaceae) extracts on stimulated equine neutrophils and myeloperoxidase activity
Boly, Rainatou; Dessy, Stephanie; Kohnen, Stephan et al

in International Journal of Molecular Medicine (2011), 28

Detailed reference viewed: 29 (4 ULg)