|
||



* Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02119; The endothelium is morphologically and
functionally adapted to meet the unique demands of
the underlying tissue. At the present time, little is
known about the molecular basis of endothelial cell diversity. As one approach to this problem, we have chosen to study the mechanisms that govern differential
expression of the endothelial cell-restricted von Willebrand factor (vWF) gene. Transgenic mice were generated with a fragment of the vWF gene containing 2,182 bp of 5
Department of Medicine,
Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215; and § Department of Medicine, Brigham and Women's
Hospital, Boston, Massachusetts 02115
flanking sequence, the first exon and first intron coupled to the LacZ reporter gene. In multiple independent lines of mice,
-galactosidase expression
was detected within endothelial cells in the brain, heart,
and skeletal muscle. In isogeneic transplantation models, LacZ expression in host-derived auricular blood
vessels was specifically induced by the microenvironment of the heart. In in vitro coculture assays, expression of both the transgene and the endogenous vWF
gene in cardiac microvascular endothelial cells
(CMEC) was upregulated in the presence of cardiac myocytes. In contrast, endothelial cell levels of thrombomodulin protein and mRNA were unchanged by the
addition of ventricular myocytes. Moreover, CMEC expression of vWF was not influenced by the addition of
3T3 fibroblasts or mouse hepatocytes. Taken together,
the results suggest that the vWF gene is regulated by vascular bed-specific pathways in response to signals
derived from the local microenvironment.
This article has been cited by other articles:
|
|