INTEGRINS INHIBIT LPS-INDUCED DNA STRAND BREAKAGE IN CULTURED LUNG ENDOTHELIAL-CELLS

Collagen inhibits acute DNA strand breakage and apoptosis in sheep pul monary artery endothelial cells (SPAEC) treated with lipopolysaccharid e (LPS). Here we tested the ability of major basement membrane compone nts, type IV collagen, laminin and fibronectin, and integrin ligands a nd anti-integrin antibodies to inhibit DNA breakage caused by LPS in S PAEC and BALB/c murine lung endothelial cells (MLEC). In situ labeling of DNA strand breaks with terminal deoxynucleotidyl transferase revea led similar DNA breakage in attached SPAEC and MLEC within 2 h after i ncubation with 1 mu g LPS/ml. Acute DNA strand breakage was reduced in cells plated on gelatin, type TV collagen, laminin, cellular fibronec tin, or plasma fibronectin. DNA breakage was also suppressed by platin g cells on surfaces coated with the integrin ligand hexapeptide, GRGDS P (40 mu g/cm(2)), but not with GRADSP. LPS-induced DNA strand breakag e was inhibited in MLEC plated on surfaces coated with antibodies to m urine alpha(5)- beta(1)-, or beta(3)- integrin subunits. Addition of a nti-integrin antibodies, but not GRGDSP, to the medium above cell mono layers inhibited strand breakage. Despite similar acute DNA breakage, MLEC exhibited less detachment and apoptosis than SPAEC, consistent wi th a difference in the sensing or processing systems for apoptosis in these two cell types. These results demonstrate that extracellular mat rices and integrin activation can inhibit the genotoxicity of LPS.