Selenoprotein P associates with endothelial cells in rat tissues

Abstract

Selenoprotein P is an extracellular heparin-binding protein that has been implicated in protecting the liver against oxidant injury. Its location in liver, kidney, and brain was determined by conventional immunohistochemistry and confocal microscopy using a polyclonal antiserum. Selenoprotein P is associated with endothelial cells in the liver and is more abundant in central regions than in portal regions. It is also present in kidney glomeruli associated with capillary endothelial cells. Staining of selenoprotein P in the brain is also confined to vascular endothelial cells. The heparin-binding properties of selenoprotein P could be the basis for its binding to tissue. Its localization to the vicinity of endothelial cells is potentially relevant to its oxidant defense function.

Low selenium status is associated with the occurrence of the pregnancy disease preeclampsia in women from the United Kingdom

“…26 It binds to endothelial cells through heparin-binding domains that enable it to coat the surface of cellular membranes, attaching more strongly in the acidotic conditions associated with areas of inflammation. 27 Its localization to endothelial cells appears to be relevant to its anti-oxidant function which has been demonstrated in the in vitro protection of human plasma from oxidation and nitration mediated by peroxynitrite 26 and in the protection of the liver from oxidant injury. 27 Whether a significant antioxidant role for selenoprotein P in preeclampsia is possible depends on the provision of reducing equivalents in the plasma to regenerate the reduced form of selenoprotein P 26 , thereby maintaining a catalytic process.…”

“…However, because selenoprotein P binds to cell membranes, high local concentrations of the 13 protein 27 , together with the continuous slow release from cells of the reductant glutathione, may represent a significant source of enzymatic activity. 28 Selenoprotein P concentrations in plasma are known to be a useful marker of selenium status though neither circulating nor tissue concentrations of selenoprotein P have been measured in human pregnancy.…”

Centrilobular Endothelial Cell Injury by Diquat in the Selenium-Deficient Rat Liver

“…The present report indicates that the earliest damage found in the liver after diquat administration is endothelial cell injury. Selenoprotein P associates strongly with hepatic sinusoidal endothelial cells (Burk et al, 1997) and we postulate that it detoxifies peroxynitrite in that location.…”

“…This protection by selenium correlates with the presence of selenoprotein P, an extracellular selenoprotein, and not with seleniumcontaining glutathione peroxidases in the cell or in the plasma. Selenoprotein P associates with endothelial cells in the liver and elsewhere (Burk et al, 1997). If it has an antioxidant role, selenoprotein P might be expected to protect endothelial cells because of this association.…”

Altered gene expression profile in chemically induced rat mammary adenocarcinomas and its modulation by an aromatase inhibitor

“…Selenoprotein P was upregulated by vorozole. Induction of selenoprotein P may provide more protection from oxidant damage and decrease the risk of mammary tumor formation (Burk et al, 1997;Koga et al, 1998). Insulin-like growth factor binding protein I (IGFBP1) was decreased in tumors treated with the highest dose of vorozole.…”