ENDOMITOPAH

Produced by all cells, extracellular vesicles (EV), including exosomes (EXOs) and microvesicles (MV), are multimolecular entities that mediate the transfer of biomolecules (e.g. nucleic acids, lipids, proteins) between cells or whole intracellular organelles such as mitochondria. A large number of mitochondria-containing MVs (Mito-MVs) originating from platelets and endothelial cells are found in the bloodstream. These data have been the starting point of a renewed interest for this type of EVs. Our project fits into this move. Through their diet, humans are daily exposed to mixtures of environmental contaminants such as polycyclic aromatic hydrocarbons (PAHs). Recently our team used in vitro and in vivo approaches to demonstrate that several PAHs, when studied individually, are able : to increase both EXO and MV production by different cells types including endothelial cells; to modify EXO and MV composition; to increase the content of glycolytic enzymes in MVs (unpublished data). But the effect of PAH cocktails has not been examined. The liver is a major site of the metabolism of ingested xenobiotics. Consequently, this organ is especially exposed to the toxicities of these chemical contaminants. Liver sinusoidal endothelial cells are critical actors of hepatic disease development and progression (e.g. fibrosis, cirrhosis, Non Alcoholic Fatty Liver Disease). In liver lobule, EVs (EXO, MVs) produced by endothelial cells can undergo fusion with recipient cells such as hepatocytes, hepatic stellate cells, or blood lymphocytes, and access to the bloodstream. PAHs are suspected to promote and worsen liver diseases and disturb mitochondrial functions. In the presence of a cocktail of PAHs, EVs produced by endothelial cells might have deleterious effects including transfer of defective mitochondria, and alteration of target cell homeostasis. To test these hypotheses, our project focused on MVs and Mito-MVs, will have three main objectives: 1) The characterization of protein signature of MVs produced by endothelial cells exposed or not to a PAH cocktail (18 PAHs that quantitatively and qualitatively correspond to those commonly detected in human food; 2) Analysis of recipient cell responses (upon exposure to MVs produced by endothelial cells) and 3) Analysis of the in vivo fate of MV/Mito-MVs (Using the zebrafish (ZF) embryo as model to investigate EV biology in vivo). The main goal of our project is, to combine in vitro and in vivo approaches to establish the role of endothelial MV/Mito-MVs and of mitochondrial transfer, in the liver toxicity upon exposure to a realistic qualitatively and quantitatively PAH cocktail. Such a project aims therefore discovered original toxic mechanism associated to exposure to dietary PAHs and to accumulate new data needed to determine if MVs and Mito-Mvs are potential biomarkers A part of our project thus aims to establish technologies devoted to the sorting of targeted sub-populations of MVs for their deep qualification. Thus, our project using Nanobioanalytical original methods and lab-on-chip will contribute to their improvement and development.