Proteomic analysis for a better understanding of the molecular mechanisms involved in the cell response to stress (hypoxia, oxidative stress, metabolic stress, atherogenic conditions, UV stress, ') in various cell models in culture.
The proteome is defined as the set of proteins expressed in a particular context in a given cell type or tissue. In the URBC, the proteomic approach is mainly used to identify new biomarkers of «stress» and to unravel the molecular mechanisms underlying the cellular responses to stress. The URBC has the equipments and resources to undertake proteomic investigations, via bidimensional gel electrophoresis. Gels are analyzed by colorimetry (and soon by fluorimetry). The proteome is studied in different cellular models: human fibroblasts either senescent or displaying SIPS (stress-induced-premature-senescence) induced by various subcytotoxic stresses (under UV or in the presence of peroxides, '), endothelial cells stressed under hypoxia or pro-atherogenic conditions. The proteomic approach is also applied to subcellular organelles such as mitochondria and lysosomes isolated from cells in which the activity of these organelles has been perturbed. After analysis of the differential expression profiles, the interesting spots (corresponding to significant expression variations), are then trypsinized and analyzed via mass spectrometry. The mass spectrometry facility is equipped with a MALDI type mass spectrometer and a Q-TOF type mass spectrometer, which allows us to identify the trypsinized proteins. The results obtained by 2D-gel proteomics are first confirmed (western blot, real-time-PCR, immunocytochemistry and confocal microscopy, '). After confirmation, functional studies are launched in order to point out the physiological importance of the over/underexpressed proteins in the investigated stressing condition .