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Updated: Aug 29, 2026
Isolation of Human Umbilical Vein Endothelial Cells and Their Use in the Study of Neutrophil Transmigration Under Flow Conditions
Published on: August 8, 2012
Granulocyte transmigration through the endothelium is regulated by the oxidase activity of vascular adhesion
Kaisa Koskinen1, Petri J Vainio, David J Smith
1MediCity Research Laboratory and Department of Medical Microbiology, Turku University. Finland.
Abstract:
Polymorphonuclear leukocytes (PMNs) migrate from the blood into areas of inflammation by binding to the endothelial cells of blood vessels via adhesion molecules. Vascular adhesion protein-1 (VAP-1) is one of the molecules mediating leukocyte-endothelial cell interactions. It is also an endothelial cell-surface enzyme (amine oxidase) that produces reactive oxygen species during the catalytic reaction. To study the role of the enzymatic activity of VAP-1 in PMN extravasation, we used an enzymatically inactive VAP-1 mutant, specific amine oxidase inhibitors (including a novel small molecule compound), and anti-VAP-1 antibodies in several flow-dependent models. The enzyme inhibitors diminished PMN rolling on and transmigration through human endothelial cells under conditions of laminar shear stress in vitro. Notably, the enzyme inactivating point mutation abolished the capacity of VAP-1 to mediate transmigration. Moreover, the new VAP-1 inhibitor effectively prevented the extravasation of PMNs in an animal model of inflammation. These data show that the oxidase activity of VAP-1 controls PMN exit from the blood during the relatively poorly understood transmigration step.
Insights
The enzymatic activity of Vascular Adhesion Protein-1 (VAP-1) is crucial for polymorphonuclear leukocytes (PMNs) to exit blood vessels during inflammation. Inhibiting VAP-1
Area of Science:
- Immunology and Inflammation Research
- Molecular and Cellular Biology
- Biochemistry and Enzymology
Background:
- Polymorphonuclear leukocytes (PMNs) extravasation is a critical inflammatory process mediated by leukocyte-endothelial cell adhesion.
- Vascular Adhesion Protein-1 (VAP-1) is an adhesion molecule and an endothelial cell-surface amine oxidase involved in leukocyte trafficking.
- The precise role of VAP-1's enzymatic activity in PMN extravasation remains incompletely understood.
Purpose of the Study:
- To investigate the contribution of VAP-1's enzymatic activity to PMN extravasation.
- To evaluate the efficacy of VAP-1 inhibitors in modulating PMN transmigration.
Main Methods:
- Utilized an enzymatically inactive VAP-1 mutant in flow-dependent models.
- Employed specific amine oxidase inhibitors, including a novel small molecule compound, and anti-VAP-1 antibodies.
- Assessed PMN rolling and transmigration across human endothelial cells under laminar shear stress in vitro and in an animal model of inflammation.
Main Results:
- VAP-1 enzyme inhibitors significantly reduced PMN rolling and transmigration.
- An enzymatically inactive VAP-1 mutant completely abrogated VAP-1's ability to mediate PMN transmigration.
- A novel VAP-1 inhibitor effectively suppressed PMN extravasation in vivo.
Conclusions:
- The oxidase activity of VAP-1 is a key regulator of PMN extravasation.
- Targeting VAP-1's enzymatic function represents a potential therapeutic strategy for inflammatory diseases.
- This study elucidates the critical role of VAP-1's enzymatic function in the transmigration step of PMN extravasation.
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