EXPRESSION OF ENDOGLIN MESSENGER-RNA AND PROTEIN IN HUMAN VASCULAR SMOOTH-MUSCLE CELLS

Endoglin, the gene linked to the autosomal dominant vascular disorder hereditary hemorrhagic telangiectasia type 1 (HHT1), encodes a 95-kDa membrane-bound proteoglycan which binds TGF beta 1 and regulates signa ling via the type I and II TGF beta receptors on the surface of vascul ar endothelial cells. Using reverse-transcription polymerase chain rea ction (RT-PCR) and Northern blot analysis we have shown that endoglin mRNA is expressed in both cultured human VSMCs and VSMCs freshly isola ted from human aortas. Northern blot analysis was also used to demonst rate that endoglin expression decreased in serum-stimulated cultured h uman VSMCs but could be maintained by exogenous TGF beta 1. Endoglin p rotein expression in human VSMCs was shown by immunocytochemistry. The se data, the first describing the existence of endoglin in VSMCs, sugg est that through regulating TGF beta 1 signaling endoglin may mediate the effects of TGF beta 1 on VSMC behavior in vitro and in vivo. (C) 1 998 Academic Press.