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THE COLrNCIL FOIi TOBACCO RESEARcH--U.S.A., I,~c. NEB" YOI{K. N. IL ~e~or~ndum From : REDACTE~ Re: Site v~s~ with REDACTED Stanfor~ University HedicaI School, November ~4, 1988. Grant No. 1970R2 entitled "Molecular biology of monocyte and platelet interactions with the endothelium." Site visitors: REDACTED Goals: To investigate the interactions of endothelial cells with monocytes and platelets and ascertain their inter-related roles in atherogenesis, inflammation and thrombosis. Results: Heparin was demonstrated to bind to human monocytes.and to c~lls of a monocytold cell llne (U937). Binding was rapid,speclfic, saturable and reversible with a dissociation constant of 0.19 uM. There were observed to be 1.9 x I0v binding sltes/cell.Lysates by heparin-affinity columns revealed a major 120 KD cell surface heparln-blndlng protein. Cell surface bound heparin was anticoag- ul~n=l~_active and induced a release of specific monocyte proteins. ~DACT~ feels this anticoagulant activity of heparin is important in modulating the the procoagulant activity of monocytes and macro- phages at sites of inflammation and thrombosis. REDACTED has established a model of endothelial cell injury in vitro with cultured umbilical vein endothelial cells and E.coli lipopoly- saccharide (LPS). Stimulation of the confluent cells with LPS elic- ited a marked degree of procoagulant activity, which was dose dependent (maximal response achieved with I ug/ml). LPS also induced the expression of endothelial cell adhesiveness toward monocytes, again, in a dose and time dependent manner. Thus, the vascular endo~thelium appears to be a highly sensitive target in vitro to immune and inflammatory mediators. He hypothesizes that such perturbation aetlvate~ specific genetic programs leading to the synthesis of new proteins which confer new endothelial functions. To prove this is one of his new goals. ~EDACTED observ@d that recently a number of platelet membrane proteins have been found on the endothelial surface, including glyco- protein (GP) IIa, Ib, IIlb (or IV), Ilia and the Iib-llke vitro- nectin alpha subun~t. A~ endothelial cell surface protein mediating leukocyte adhesion to stimulated endothelial cells has also been reported. SKmee..a sys~emaZ~= a~alys~$ of these proteins under resting and perturbed conditions has not yet been reported, he plans to undertake this as a major project; to determine which .of them is most responsive to perturbation. In particular he is interested in the role of GPlla/lllb in clot formation. He has further concluded =ha= GP serves as a receptor for thrombospond~n on act±rated platele=~, thus may ~lay an important role in pla~elet aggregation.