Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
Increased cerebrovascular permeability and cellular infiltration of predominantly monocytes in the central nervous system (CNS) mark the onset of various neuroinflammatory diseases. To enter the CNS, monocytes have to cross the blood-brain barrier (BBB) that is primarily formed by the specialized brain endothelial cells (EC). Cellular trafficking requires the participation of the brain EC to actively disengage its tight junctions and rearrange its cytoskeleton, allowing transendothelial migration. However, before monocytes cross the brain vascular barrier, they first need to become firmly attached onto the brain endothelium. Here we propose that this firm adhesion of monocytes contributes to disease progression by triggering intracellular events in the brain EC leading to monocytic accumulation in the brain. The primary goal of this project is to identify key mechanisms that control monocyte migration into the CNS, and in particular determine cellular changes of the brain EC that contribute to the migratory process. Specific emphasis will be on protein regulation and signal transduction processes activated in cerebral EC upon interaction with monocytes, and the cellular outcome of such events. We will identify brain EC specific proteins regulated upon monocyte attachment by performing proteomics, followed by amino acid sequencing and database search and characterize changes in phosphorylation, redox and acetylation status. These protein modifications are fast and transient, but will have a major impact on cytoskeletal and tight junction organization and monocyte migration. The functional relevance of discovered proteins in these processes will be validated in well-established in vitro models. Life cell imaging will be used to quantify real-time cellular dynamics of the brain endothelium as a result of monocyte adhesion. These studies will evidently shed more light on the mechanisms underlying neuroinflammatory diseases and lead to the identification of new targets and therapeutic strategies to diminish monocyte recruitment into the brain, hence limiting disease progression.