Rap1 GTPase inhibits leukocyte transmigration by promoting endothelial barrier function.
The passage of leukocytes out of the blood circulation and into tissues is necessary for the normal inflammatory response, but it also occurs inappropriately in many pathological situations. This process is limited by the barrier presented by the junctions between adjacent endothelial cells that line blood vessels. Here we show that activation of the Rap1 GTPase in endothelial cells accelerated de novo assembly of endothelial cell-cell junctions and increased the barrier function of endothelial monolayers. In contrast, depressing Rap1 activity by expressing Rap1GAP led to disassembly of these junctions and increased their permeability. We also demonstrate that endogenous Rap1 was rapidly activated at early stages of junctional assembly, confirming the involvement of Rap1 during junctional assembly. Intriguingly, elevating Rap1 activity selectively within endothelial cells decreased leukocyte transendothelial migration, whereas inhibiting Rap1 activity by expression of Rap1GAP increased leukocyte transendothelial migration, providing physiological relevance to our hypothesis that Rap1 augments barrier function of inter-endothelial cell junctions. Furthermore, these results suggest that Rap1 may be a novel therapeutic target for clinical conditions in which an inappropriate inflammatory response leads to disease.
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- rap1 GTP-Binding Proteins
- Leukocytes
- Humans
- Endothelial Cells
- Egtazic Acid
- Cyclic AMP
- Cells, Cultured
- Cell Movement
- Biochemistry & Molecular Biology
- 34 Chemical sciences
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- rap1 GTP-Binding Proteins
- Leukocytes
- Humans
- Endothelial Cells
- Egtazic Acid
- Cyclic AMP
- Cells, Cultured
- Cell Movement
- Biochemistry & Molecular Biology
- 34 Chemical sciences