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Endothelial cell confluence regulates Weibel-Palade body formation.
Gareth J Howell1, Shane P Herbert, Jennifer M Smith
1School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
Molecular Membrane Biology
|March 15, 2005
Summary
Weibel-Palade body (WPB) formation in endothelial cells is linked to cell confluence. As cells divide and passage number increases, WPB formation decreases, impacting Von Willebrand factor storage.
Area of Science:
- Cell Biology
- Endothelial Cell Biology
- Vascular Biology
Background:
- Weibel-Palade bodies (WPBs) are characteristic secretory granules of mammalian endothelium.
- These WPBs store Von Willebrand factor (VWF), a crucial vascular antigen.
- The relationship between WPB formation, endothelial identity, and proliferation requires further investigation.
Purpose of the Study:
- To investigate the link between Von Willebrand factor (VWF) storage in Weibel-Palade bodies (WPBs) and endothelial cell proliferation.
- To determine how cell confluence and passage number affect WPB formation and VWF accumulation in human umbilical vein endothelial cells (HUVECs).
Main Methods:
- Monitoring cellular accumulation of VWF within WPBs in HUVECs.
- Assessing VWF levels as a function of cell proliferation, confluence, and passage number.
- Utilizing biochemical studies to analyze VWF processing and localization within the secretory pathway.
Main Results:
- Increased passage number significantly reduced the percentage of HUVECs containing WPBs, despite VWF presence in the secretory pathway.
- The endothelial marker PECAM-1 remained present on all cells, indicating partial maintenance of endothelial identity.
- Immature pro-VWF was detected in sub-confluent cells, while mature VWF accumulated in confluent cells, suggesting differential sorting.
Conclusions:
- Weibel-Palade body formation is intrinsically linked to the development of a confluent endothelial monolayer.
- Endothelial cell proliferation and passage number influence the capacity for WPB formation and VWF packaging.
- Differential sorting and packaging of VWF occur along the secretory pathway depending on endothelial cell confluence.