6 research outputs found
Ătude des effets des stimulateurs des dĂ©fenses naturelles des plantes sur lâimmunitĂ© innĂ©e des vertĂ©brĂ©s et mise en Ă©vidences des acteurs communs par une approche in silico
Prod 2016-283 IPM SPE CNRS DOCTLes pesticides, utilisĂ©s pour protĂ©ger les cultures, ont souvent des effets dĂ©lĂ©tĂšres pour la santĂ© humaine et lâenvironnement. Des alternatives telles que les SDN sont actuellement dĂ©veloppĂ©es pour rĂ©duire leur utilisation. Compte tenu de la similaritĂ© des motifs molĂ©culaires induisant l'immunitĂ© chez les plantes et les animaux, les SDN pourraient interagir avec le systĂšme immunitaire innĂ© des vertĂ©brĂ©s. Toutefois, lors du processus d'homologation des pesticides, aucun test ne sâintĂ©resse directement Ă leurs effets pro/anti-inflammatoires bien que des maladies soient favorisĂ©es par lâinflammation chronique. En utilisant des cellules mononuclĂ©aires du sang pĂ©riphĂ©rique humain, nous avons Ă©tudiĂ© lâeffet cytotoxique et pro/anti-inflammatoire (production d'IL1B) des SDN commercialisĂ©s, le but Ă©tant de dĂ©velopper un test de sĂ©curitĂ© sanitaire applicable en routine. Deux SDN ont eu des effets marquĂ©s sur lâactivitĂ© mĂ©tabolique et sur la production d'IL1B par les cellules humaines. Pour vĂ©rifier si ces produits avaient un effet similaire chez dâautres organismes, nous avons utilisĂ© des larves de poisson zĂšbre (Danio rerio). Comme chez l'humain, ces deux SDN ont soit un effet pro-inflammatoire ou soit un fort effet toxique. L'immunitĂ© innĂ©e est une fonction conservĂ©e chez tous les eucaryotes et il est probable que certains rĂ©cepteurs aient Ă©tĂ© conservĂ©s tout au long de l'Ă©volution entre les plantes et les animaux. Les travaux menĂ©s ont eu pour but dâidentifier par bio-informatique de nouveaux rĂ©cepteurs chez les plantes Ă partir des connaissances obtenus chez l'homme. Notre Ă©tude a permis de mettre en Ă©vidence de nouveaux rĂ©cepteurs putatifs
Inflammatory Effects of the Plant Protection Product Stifenia (FEN560) on Vertebrates
Plant defense stimulators (PDSs) rely on the activation of plant innate immunity in order to protect crops against various pests. These molecules are thought to be a safer alternative to classical plant protection products. Given that innate immune systems share common features in plants and vertebrates, PDS can potentially cross-react with innate immunity of non-target organisms. To test this hypothesis, we studied effects of the commercial PDS Stifenia (FEN560), which is composed of crushed fenugreek seeds. We tested various concentrations of Stifenia (0.03â1âmg mLâ1) on human peripheral blood mononuclear cells and checked, 20âh later, cell metabolic activity (MA) using XTT assay, cell death by flow cytometry analysis, and IL-1ÎČ inflammatory cytokine released in the culture medium using ELISA. Stifenia induced a general decrease of the cell MA, which was concomitant with a dose-dependent release of IL-1ÎČ. Our results highlight the activation of human immune cells. The inflammatory effect of Stifenia was partially inhibited by pan-caspase inhibitor. Accordingly, Stifenia induced the release of p20 caspase-1 fragment into the culture medium suggesting the involvement of the NLRP3 inflammasome. Furthermore, we observed that Stifenia can induce cell death. We also tested the effect of Stifenia on Zebrafish larvae. After 24âh of exposure, Stifenia induced a dose-dependent IL-1ÎČ and TNFα gene expression. The human-cell-based approach developed in this work revealed a high sensitivity concerning inflammatory properties of a plant protection product. These tests could be routinely used to screen the potential adverse effects of this type of compounds. Finally, our results suggest a potential danger of using extensively certain PDS for crop protection
Inflammatory Effects of the Plant Protection Product Stifenia (FEN560) on Vertebrates
International audiencePlant defense stimulators (PDSs) rely on the activation of plant innate immunity in order to protect crops against various pests. These molecules are thought to be a safer alternative to classical plant protection products. Given that innate immune systems share common features in plants and vertebrates, PDS can potentially cross-react with innate immunity of non-target organisms. To test this hypothesis, we studied effects of the commercial PDS Stifenia (FEN560), which is composed of crushed fenugreek seeds. We tested various concentrations of Stifenia (0.03-1âmg mL(-1)) on human peripheral blood mononuclear cells and checked, 20âh later, cell metabolic activity (MA) using XTT assay, cell death by flow cytometry analysis, and IL-1ÎČ inflammatory cytokine released in the culture medium using ELISA. Stifenia induced a general decrease of the cell MA, which was concomitant with a dose-dependent release of IL-1ÎČ. Our results highlight the activation of human immune cells. The inflammatory effect of Stifenia was partially inhibited by pan-caspase inhibitor. Accordingly, Stifenia induced the release of p20 caspase-1 fragment into the culture medium suggesting the involvement of the NLRP3 inflammasome. Furthermore, we observed that Stifenia can induce cell death. We also tested the effect of Stifenia on Zebrafish larvae. After 24âh of exposure, Stifenia induced a dose-dependent IL-1ÎČ and TNFα gene expression. The human-cell-based approach developed in this work revealed a high sensitivity concerning inflammatory properties of a plant protection product. These tests could be routinely used to screen the potential adverse effects of this type of compounds. Finally, our results suggest a potential danger of using extensively certain PDS for crop protection
Effect of commercially available Plant Defence Stimulators (PDS) on human innate immunity
International audiencePDS (Plant defence stimulators) constitute a recent alternative to pesticides used for crop protection. These compounds called elicitors are of diverse nature, but they all act by stimulating innate immune system of plants. So, plants can better fight pathogens. Furthermore, there are many similarities in pathogen perception systems and cellular signalling in plants and animals. It is well established that many elicitors stimulate both human and plant innate immunity (Zipfel and Felix, 2005). Therefore, it is likely that human innate immunity could be modulated by PDS. The aim of this study is to evaluate pro/anti-inflammatory activity of five different commercially available PDS on human cell models. We studied the pro/anti-inflammatory effect of PDS (BionÂź 50WG, Stifenia...) on human peripheral blood mononuclear cells (PBMC). These cells are exposed during twenty hours to various concentrations of PDS or their corresponding active molecules. Pro-inflammatory action is evaluated by measuring the quantity of the inflammatory cytokine IL-1ÎČ in the cells supernatants using ELISA test. To study anti-inflammatory effect, we used PBMC treated with LPS to trigger a basal inflammatory response. We then checked if PDS delivered at the same time as LPS modified IL-1ÎČ production. In addition, in all the experiments, the viability is evaluated with a XTT test. PDS, which were however used at equal or lower concentrations than in the fields, show different profiles in terms of cytotoxicity and inflammatory modulation. For example, Stifenia was slightly cytotoxic at 1 mg/ml and pro-inflammatory at 0,3 and 1 mg/ml concentrations. Conversely, BionÂź 50WG at dosages from 0,3 mg/ml dose-dependently inhibited IL-1ÎČ production and proved to be anti-inflammatory. Interestingly, some active molecules have not the same inflammatory profile than their respective formulated PDS from the market. Our results indicate that PDS can differently interact with human innate immunity. We hope to use these particularities to better understand the innate immunity pathways that could be common in plants and animals
Lutter contre les infections bactériennes : le systÚme immunitaire des plantes est aussi trÚs efficace !
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Role of mannitol metabolism in the pathogenicity of the necrotrophic fungus Alternaria brassicicola
In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternada brassicicola. Mannitol metabolism was examined during infection of Brass/ca oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e., a mannitol dehydrogenase (AbMdh), and a mannito1-1-phosphate dehydrogenase (AbMpd). Knockout mutants deficient for AbMdf7 or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behavior were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicrcola to efficiently accomplish key steps of its pathogenic life cycle