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Functional and morphological changes induced by tunicamycin in dividing and confluent endothelial cells
1Department of Pharmacology, University of Melbourne, Victoria, Australia.
Experimental Cell Research
|February 1, 1992
Summary
Inhibiting glycoprotein synthesis in bovine aortic endothelial cells with tunicamycin disrupted cell structure and function. This highlights the critical role of glycoproteins in maintaining endothelial cell adhesion and vascular integrity.
Area of Science:
- Cell Biology
- Biochemistry
- Vascular Biology
Background:
- Endothelial cells form the inner lining of blood vessels, playing a vital role in vascular function.
- Glycoproteins are essential components of cell membranes and the extracellular matrix, involved in cell adhesion and signaling.
- Tunicamycin is a known inhibitor of N-acetylglucosamine-1-phosphate transferase, an enzyme critical for glycoprotein synthesis.
Purpose of the Study:
- To investigate the effects of inhibiting glycoprotein synthesis on cultured bovine aortic endothelial cells.
- To determine the impact of tunicamycin-induced inhibition on endothelial cell morphology, cell-cell adhesion, and monolayer permeability.
Main Methods:
- Cultured bovine aortic endothelial cells were treated with varying concentrations of tunicamycin.
- N-acetylglucosamine-1-phosphate transferase activity and [3H]mannose incorporation were measured to assess glycoprotein synthesis inhibition.
- Cell morphology was examined using light and electron microscopy.
- Endothelial cell monolayer permeability was assessed using 125I-albumin and [3H]inulin tracers.
Main Results:
- Tunicamycin caused a concentration-dependent inhibition of N-acetylglucosamine-1-phosphate transferase activity and reduced [3H]mannose incorporation.
- Significant morphological changes were observed, including cell elongation, irregular surface, and increased interstitial space.
- Electron microscopy revealed dilation and accumulation of electron-dense material in the rough endoplasmic reticulum.
- The distribution of laminin and fibronectin was altered, and endothelial permeability to albumin and inulin increased.
Conclusions:
- Glycoprotein synthesis is crucial for maintaining the structural integrity and cell-cell adhesion of endothelial cells.
- Inhibition of glycoprotein synthesis leads to morphological alterations and functional impairment of the endothelial barrier.
- These findings underscore the importance of glycoproteins in vascular health and endothelial lining function.