AJP - Lung Cellular and Molecular Physiology, Vol 269, Issue 2 171-L177, Copyright © 1995 by American Physiological Society
Collagen is a survival factor against LPS-induced apoptosis in cultured sheep pulmonary artery endothelial cells
D. G. Hoyt, R. J. Mannix, J. M. Rusnak, B. R. Pitt and J. S. Lazo
Department of Pharmacology, University of Pittsburgh School of Medicine, Pennsylvania 15261, USA.
Lipopolysaccharide (LPS) causes direct pulmonary endothelial injury that
can precipitate cell death. We investigated the ability of LPS to produce
apoptosis in sheep pulmonary artery endothelial cells (SPAEC) grown in
monolayer on plastic or collagen. When SPAEC were grown on plastic, LPS
(100 ng/ml) caused internucleosomal DNA fragmentation (IDF) to 180- to
200-base pair ladders after 4 h. Higher-order chromatin damage, producing
50-kilobase DNA fragments, occurred within 2 h. Significant DNA strand
breaks were seen in attached cells within 1 h incubation with > or = 1
ng LPS/ml, using in situ labeling by break extension (ISBE). DNA strand
breakage in attached cells peaked after 2 h and remained elevated after 4
h. Detachment of SPAEC from the monolayer did not begin until 4 h. SPAEC
cultured on collagen were protected from LPS-induced apoptosis; DNA damage
measured by IDF, high-molecular-weight DNA fragmentation, and ISBE were
suppressed. The protective effect of collagen was not due to inactivation
of LPS. Thus LPS-induced apoptosis occurs in SPAEC after genotoxic damage
and this process is suppressed by the extracellular matrix.
