JAM-2, a novel immunoglobulin superfamily molecule, expressed by endothelial and lymphatic cells
M Aurrand-Lions1, L Duncan, C Ballestrem
1Department of Pathology, Centre Medical Universitaire, 1 rue Michel-Servet, CH-1211 Geneva, Switzerland. michel.aurrand-lions@medecine.unige.ch
Insights
Researchers discovered a new molecule, JAM-2, crucial for cell adhesion in blood vessels. This junctional adhesion molecule (JAM-2) plays a key role in endothelial cohesion and vascular development.
Area of Science:
- Vascular Biology
- Cell Adhesion Molecules
- Immunology
Background:
- Cell-cell contacts are fundamental for tissue development and function.
- Endothelial cohesion is vital for vascular system organization and growth.
- Identifying novel molecules involved in these processes is crucial.
Purpose of the Study:
- To identify and characterize novel junctional adhesion molecules involved in endothelial cell contacts.
- To investigate the expression pattern and localization of the identified molecule.
- To elucidate the functional role of the novel molecule in cell-cell adhesion and vascular integrity.
Main Methods:
- Selective RNA display for transcript identification.
- Coculture of endothelial and tumor cells.
- Antibody staining for protein localization.
- Real-time video microscopy.
- Transfection of cell monolayers with JAM-2 cDNA.
- Measurement of paracellular permeability.
Main Results:
- A novel junctional adhesion molecule, JAM-2, was identified.
- JAM-2 expression is high during embryogenesis and in specific adult tissues (lymph nodes, Peyer's patches, kidney).
- JAM-2 localizes to newly formed cell-cell contacts and tight junctional complexes.
- Overexpression of JAM-2 reduces paracellular permeability, suggesting a role in sealing cell junctions.
Conclusions:
- JAM-2 is a novel vascular molecule involved in interendothelial junctional complexes.
- JAM-2 contributes to endothelial cohesion and vascular barrier function.
- Further research into JAM-2's role in vascular development and disease is warranted.
Abstract:
Cell-cell contacts are essential for morphogenesis and tissue function and play a vital role in mediating endothelial cohesion within the vascular system during vessel growth and organization. We identified a novel junctional adhesion molecule, named JAM-2, by a selective RNA display method, which allowed identification of transcripts encoding immunoglobulin superfamily molecules regulated during coculture of endothelial cells with tumor cells. The JAM-2 transcript is highly expressed during embryogenesis and is detected in lymph node and Peyer's patches RNA of adult mice. Accordingly, antibodies specific for JAM-2 stain high endothelial venules and lymphatic vessels in lymphoid organs, and vascular structures in the kidney. Using real time video microscopy, we show that JAM-2 is localized within minutes to the newly formed cell-cell contact. The role of the protein in the sealing of cell-cell contact is further suggested by the reduced paracellular permeability of cell monolayer transfected with JAM-2 cDNA, and by the localization of JAM-2 to tight junctional complexes of polarized cells. Taken together, our results suggest that JAM-2 is a novel vascular molecule, which participates in interendothelial junctional complexes.
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