AJP - Lung Cellular and Molecular Physiology, Vol 273, Issue 6 1141-L1146, Copyright © 1997 by American Physiological Society
Effect of hypercarbia on surface proteins of cultured bovine endothelial cells
S. Rounds, D. Piggott, D. D. Dawicki and H. W. Farber
Pulmonary and Critical Care Section, Providence Veterans Affairs Medical Center, Rhode Island 02908, USA.
Hypercarbia is a common complication of respiratory failure, and the
technique of "permissive hypercapnia" is used to ventilate individuals with
increased peak airway pressures on mechanical ventilators, resulting in
elevated arterial PCO2. We studied the effects of hypercarbia on cultured
bovine aortic and main pulmonary artery endothelial cell surface proteins,
assessing cell surface iodination using lactoperoxidase bound to latex
microspheres. We found that 4 h of exposure to 10% CO2 increased the
display of substances of apparent molecular masses of 27, 47, and 52 kDa.
This effect was not mimicked by acidotic media. Western blots of detergent
extracts of main pulmonary artery endothelial cell monolayers did not show
increased expression of carbonic anhydrase IV (molecular mass = 52 kDa)
after incubation under hypercarbic conditions. Hypercarbia did not change
the pattern of [35S]methionine incorporation into endothelial cell
proteins. We conclude that hypercarbia of 4-h duration changes iodinated
endothelial cell surface proteins. We speculate that this effect may be
related to changes in secretion or display of apical cell
membrane-associated proteins.
