PECAM-1 (CD31) expression modulates bleeding time in vivo.
PECAM-1 is a 130-kd member of the Ig superfamily present on endothelial cells, platelets, polymorphonuclear leukocytes, monocytes, and lymphocytes. Its expression begins early in development and persists through adulthood. PECAM-1 functions as an adhesion and signaling molecule between adjacent endothelial cells and between endothelial cells and circulating blood elements. Antibodies directed against PECAM-1 have been shown to affect angiogenesis, endothelial cell migration, and polymorphonuclear leukocyte transmigration. Furthermore, its dimerization is associated with the modulation of integrin affinity. Antibody inhibition studies suggest that PECAM-1 plays a role in modulating thrombosis; however, recent in vitro aggregation studies performed on platelets harvested from PECAM-1-deficient mice revealed no abnormalities. In this report we demonstrate prolonged in vivo bleeding times in PECAM-1-deficient mice. This abnormality was not corrected when wild-type hematopoietic precursors were engrafted into marrow-ablated PECAM-1-deficient mice. Furthermore, normal bleeding times were observed when marrow-ablated wild-type mice were engrafted with hematopoietic precursors harvested from PECAM-1-deficient mice. These studies are consistent with a role for PECAM-1 in modulating thrombosis in the vasculature, which is potentially mediated by endothelial cell PECAM-1 expression.
Mahooti
S
S
Department of Pathology, Yale University School of Medicine, New Haven, CT 06520-8023, USA.
Graesser
D
D
Patil
S
S
Newman
P
P
Duncan
G
G
Mak
T
T
Madri
J A
JA
D000818:Animals; D001760:Bleeding Time; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism; D006579:Heterozygote; D006720:Homozygote; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010976:Platelet Count; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics; D013997:Time Factors
D019408:Platelet Endothelial Cell Adhesion Molecule-1