Human cellular prion protein hPrPC is sorted to the apical membrane of epithelial cells.

Propagation of the scrapie isoform of the prion protein (PrP(Sc)) depends on the expression of endogenous cellular prion (PrP(C)). During oral infection, PrP(Sc) propagates, by conversion of the PrP(C) to PrP(Sc), from the gastrointestinal tract to the nervous system. Intestinal epithelium could serve as the primary site for PrP(C) conversion. To investigate PrP(C) sorting in epithelia cells, we have generated both a green fluorescent protein (EGFP) or hemagglutinin (HA) tagged human PrP(C) (hPrP(C)). Combined molecular, biochemical, and single living polarized cell imaging characterizations suggest that hPrP(C) is selectively targeted to the apical side of Madin-Darby canine kidney (MDCKII) and of intestinal epithelia (Caco2) cells.

Expression and localization of cellular prion and COMMD1 proteins in human placenta throughout pregnancy.

Copper is an essential trace element for successful pregnancy. However, the mechanisms by which copper is transported from maternal circulation to the fetus have not been clearly elucidated. Two proteins, cellular prion (PrP(C)) and COMMD1, are known to be responsible for prion diseases and canine copper toxicosis, respectively, and are thought to play a role in copper homeostasis. However, their placental expression and localization throughout human gestation are still unknown. In this study, we used quantitative RT-PCR, western blotting and immunohistochemistry to investigate in detail the expression and localization of PrP(C) and COMMD1 proteins in human placenta throughout pregnancy. Our results show that both proteins are expressed in human placenta. PrP(C) showed the highest mRNA and protein expression levels during the first trimester of pregnancy. PrP(C) and COMMD1 proteins are similarly localized within the placental villi. Both proteins are present in the syncytiotrophoblast, the cytotrophoblast, vascular endothelial cells and Hofbauer cells. These data offer some insights into possible roles for PrP(C) and COMMD1 within the placenta.