Session: Parallel session 1 - Health and biological sciences

Constitution of the endothelial cells, brain pericytes and astrocytes “reference proteomes” through label-free fractioned and quantitative mass spectrometry approaches

Brain microvessel endothelial cells (ECs), brain pericytes (BPs) and astrocytes (ACs) are three cell types constituting to the so-called neurovascular unit and of importance for the establishment and the maintenance of the blood-brain barrier (BBB) phenotype held by ECs. Classical proteomics studies on these cells have been led using whole cell lysates and underestimated the proteins within each cell type due to the abundance and the quenching of cytoplasmic proteins in the identification and quantification of proteins from other subproteomes. The main goal of this study is to enhance the identification of ECs, BPs and ACs proteins through a fractioned approach to better sort out the proteins from cell membranes, nucleus and insoluble proteins that are mainly cytoskeleton-associated proteins. This approach significantly improves the identification of proteins in all cell types, in particular for membrane proteins and plasma membrane proteins. ACs proteome is also analysed to sort out so-called “body” and “foot”-enriched proteins. Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) analyses on the three cell types allow us to evaluate the enrichment or the depletion of commonly expressed proteins. This initial preliminary study led on immature ECs, BPs and ACs, i.e. individually and not after a grouped in vitro culture system to mimic the BBB phenotype, bring evidence of the reference proteomes of each cell type, and will be further complete with another study focused on the proteomes of these cell types after BBB maturation.