Etude du pouvoir inhibiteur de molécules thérapeutiques usuelles sur les propriétés oxydantes des neutrophiles et de la myéloperoxydase

L'accumulation et la surstimulation des leucocytes neutrophiles (PMNs) et de la myéloperoxydase (MPO), cellules et enzyme essentielles du système immunitaire, au sein des tissus sont caractéristiques de nombreuses pathologies inflammatoires chroniques. La recherche de molécules capables d'inhiber l'impact oxydant de ces marqueurs inflammatoires est une piste pour l'établissement de traitements. Le repositionnement de molécules thérapeutiques est une voie privilégiée. Dans ce travail, une démarche multidisciplinaire, associant des techniques expérimentales complémentaires : spectroscopies (absorption, fluorescence et RPE), voltammétrie cyclique et docking, a permis d'évaluer les propriétés anti-inflammatoires de molécules ayant déjà une utilité thérapeutique et ayant montré des propriétés antioxydantes : morphine, propofol, six statines et six anticancéreux. La capacité réductrice des molécules et leur aptitude à piéger des espèces réactives de l'oxygène ont été évaluées. L'action inhibitrice des composés d'intérêt sur les phénomènes de flambée respiratoire et de dégranulation des PMNs, ainsi que sur les cycles de chloration et de peroxydase de la MPO, a été étudiée et les mécanismes explorés. La méthodologie mise en place a mis en lumière les propriétés immunomodulatrices intéressantes de certaines molécules, laissant entrevoir des possibilités d'utilisation dans le cadre du traitement contre l'inflammation

Study of the antioxidant action of two analgesic compounds, morphine and propofol, on the activity of MPO and HRP

Although acute inflammation can efficiently be treated, the treatment of chronic inflammatory pathologies is still a challenge to rise. As marker of inflammation, the enzyme Myeloperoxidase (MPO) is a choice target for the establishment of a treatment. Indeed, the uncontrolled release in the extracellular medium of MPO, marker of inflammation, along with the release of ROS, causes severe damages on biological tissues. The modulation of the enzyme activity, by an inhibitor, might constitute an approach to treat excessive inflammation. An interesting pathway is to give a second life to clinical-used molecules, presenting antioxidant and anti-inflammatory properties. According to several studies, morphine and propofol (PPF), which are already known for their analgesic and anesthetic properties, present an antioxidant activity. Therefore, these reducing molecule can potentially pretend to be MPO inhibitors

Comparison of the action of morphine with potential inhibitors on the activity of MPO and HRP

The uncontrolled release in the extracellular medium of MPO, marker of inflammation, along with the release of ROS, causes severe damages on biological tissues. The modulation of the enzyme activity might constitute an approach for the treatment of excessive inflammation. According to several studies, morphine, which is already known for its analgesic properties, seems to present an antioxidant activity. Therefore, this reducing molecule can potentially pretend to be an inhibitor of MPO

Effect of morphine and propofol on the activation of equine neutrophils: An EPR spin trapping study

Inflammation is a complex phenomenon involving chemical and enzymatic mechanisms. The polymorphonuclear neutrophil leukocytes (PMNs) play an essential immunomodulatory role by releasing harmful reactive oxygen species (ROS) and oxidant enzymes. During the respiratory burst, the enzymatic complex NADPH oxidase produces the ROS precursor: superoxide anion (O_2^( . −)), to initiate the invasive microorganisms degradation. Inflammatory pathologies induce an excessive stimulation of the neutrophils and an uncontrolled production and release of ROS in the extracellular medium, leading to severe tissue damages. The treatment of chronic pathologies is still a challenge to rise. For this reason, the research of potential anti-inflammatory molecules, able to inhibit the oxidant enzymes and/or to scavenge ROS, is an important part of biomedical research. Morphine and propofol, in addition to their analgesic and anaesthetic action respectively, presents antioxidant properties 3,4. However, only few data has been reported on their potential superoxide anion scavenger and inhibitory effect on the neutrophil respiratory burst

Assessment of anti-inflammatory-like, antioxidant activities and molecular docking of three alkynyl-substituted 3-ylidene-dihydrobenzo[d]isothiazole 1,1-dioxide derivatives.

The presence of enyne and benzoisothiazole functions in the molecular architecture of compounds 1, 2 and 3 were expected to provide biochemical activities. In the present work, we first examined the molecular surface contact of three alkynyl-substituted 3-ylidenedihydrobenzo[d] isothiazole 1,1-dioxides. The analysis of the Hirshfeld surfaces reveals that only compound 3 exhibited a well-defined red spots, indicating intermolecular interactions identified as S-O⋯H, C-H⋯O and C-O⋯H contacts. Comparative fingerprint histograms of the three compounds show that close pair interactions are dominated by C-H⋯H-C contact. By UV-visible analysis, compound 1 showed the most intense absorbances at 407 and 441 nm, respectively. The radical scavenging activity explored in the DPPH test, shows that only 1 exhibited low anti-radical activity. Furthermore, cellular antioxidant capacity of benzoisothiazoles 1-3 was investigated with PMA-activated HL-60 cells using chemiluminescence and fluorescence techniques in the presence of L-012 and Amplex Red probe, respectively. Results highlight that compound 1 exhibited moderate anti-ROS capacity while compounds 2 and 3 enhanced ROS production. The cytotoxicity test performed on HL-60 cells, using the MTS assay, confirmed the lack of toxicity of the tested benzoisothiazole 1 compared to 2 and 3 which show low cytotoxicity (≤30%). Anti-catalytic activity was evaluated by following the inhibitory potential of the benzoisothiazoles on MPO activity and depicted benzoisothiazoles-MPO interactions by docking. Both SIEFED and docking studies demonstrated an anti-catalytic activity of the tested benzoisothiazoles towards MPO with the best activity for compound 2

Propofol inhibits the myeloperoxidase activity by acting as substrate through a redox process.

peer reviewed[en] BACKGROUND: Propofol (2,6-diisopropylphenol) is frequently used as intravenous anesthetic agent, especially in its injectable form (Diprivan), to initiate and maintain sedative state during surgery or in intensive care units. Numerous studies have reported the antioxidant and anti-inflammatory effect of propofol. The oxidant enzyme myeloperoxidase (MPO), released from activated neutrophils, plays a key role in host defense. An increase of the circulating MPO concentration has been observed in patients admitted in intensive care unit and presenting a systemic inflammatory response related to septic shock or trauma. METHODS: This study investigates the immunomodulatory action of propofol and Diprivan as inhibitor of the oxidant activity of MPO. The understanding of the redox action mechanism of propofol and Diprivan on the myeloperoxidase chlorination and peroxidase activities has been refined using the combination of fluorescence and absorption spectroscopies with docking and cyclic voltammetry. RESULTS: Propofol acts as a reversible MPO inhibitor. The molecule interacts as a reducing substrate in the peroxidase cycle and promotes the accumulation of compound II. At acidic pH (5.5), propofol and Diprivan do not inhibit the chlorination activity, but their action increases at physiological pH (7.4). The main inhibitory action of Diprivan could be attributed to its HOCl scavenging property. GENERAL SIGNIFICANCE: Propofol can act as a reversible MPO inhibitor at clinical concentrations. This property could, in addition to other previously proven anti-inflammatory actions, induce an immunomodulatory action, beneficial during clinical use, particularly in the treatment of systemic inflammation response syndrome

Study of the antioxidant action of morphine on the peroxidase cycle of MPO and HRP

Besides its analgesic action, morphine presents antioxidants properties and therefore an interest as inhibitor of MPO. Moreover, it has been proved that morphine can inhibit the ROS production and the PMN degranulation. Therefore, it seems like morphine has a direct action on MPO activities but the exact mechanism of action is still to be elucidated. The aim of the study is to investigate the potential antioxidant activity of morphine on the peroxidation cycle of MPO, in comparison to another peroxidase, Horseradish Peroxidase (HRP)

Morphine, a potential inhibitor of myeloperoxidase activity

Morphine is an opioid alkaloid commonly used in clinical practice for its analgesic properties. The phenolic hydroxyl group of that phenanthrene derivative is pivotal for binding to opioid receptors but it may also be responsible for the antioxidant behavior of morphine reported in several in vitro experiments. In this study, we assessed the effect of morphine on myeloperoxidase (MPO), a hemic enzyme from azurophilic granules of polymorphonuclear neutrophils involved in the production of cytotoxic and microbicidal reactive oxidants during inflammatory response. Specific immunological extraction followed by enzyme detection (SIEFED) and molecular modeling (docking) were performed to study the potential anti-catalytic action of morphine on MPO in comparison with the inhibitory effects of reference antioxidant molecules quercetin, gallic acid and ascorbic acid. The reducing action of morphine on the MPO peroxidase cycle has been investigated using electron paramagnetic resonance (EPR) and UV-visible absorption spectroscopy. Morphine acted as a reducing substrate in the peroxidase cycle of MPO and therefore protected the enzyme against the suicide action of its natural substrate, hydrogen peroxide. The SIEFED experiments associated with the docking study, further demonstrated a lack of strong and sustained anti-catalytic activity of morphine. In summary, from the results of this study, it appears that morphine acts as a weak and reversible inhibitor of MPO that may nonetheless contribute to immunomodulatory and antioxidant effects of this opioid analgesic in vivo. © 2018 Elsevier B.V