Endoglin expression in human and rat mesangial cells and its upregulation by TGF-beta 1

Endoglin is a component of the TGF-beta receptor complex present in the kid ney at the human glomerular mesangium. Since the cellular origin of the glo merular endoglin is unknown, in the present study we investigated the expre ssion of endoglin in mesangial cells in culture, as well as their response to TGF-beta1. Western and Northern blot analysis identified the expression of endoglin protein and mRNA transcript in both human and rat mesangial cel ls. Flow cytometry and immunocytochemistry analyses revealed that endoglin is present on the cell membrane. Exogenous TGF-beta1 stimulated not only th e expression of collagen alpha1 (I) I and TGF-beta1, but also that of endog lin. These data provide the first evidence for the expression of endoglin i n mesangial cells, as well as its upregulation by TGF-beta1, thus suggestin g that endoglin may have a role in modulating the effects of TGF-beta1 on t he glomerular mesangium. (C) 2001 Academic Press.