Prion protein expression in bovine podocytes and extraglomerular mesangial cells

Abstract

The cellular form of the prion protein (PrP(c)) is thought to be a substrate for an abnormal isoform of the prion protein (PrP(sc)). One emerging hypothesis is that the proposed conversion phenomenon takes place at the site at which the infectious agent meets PrP(c). PrP(c) is abundant in the central nervous system, but little is known about the cell-type-specific distribution of PrP(c) in non-neuronal tissues of cattle. We have studied whether PrP(c), a protein found predominantly in neurons, also exists in bovine podocytes, since neurons and podocytes share a large number of similarities. We have therefore examined the expression of PrP(c) by immunohistochemistry, reverse transcription/polymerase chain reaction and enzyme-linked immunosorbent analysis. Immunostained serial sections and specific antibodies against PrP(c) have revealed that PrP(c) is selectively localized in podocytes and is particularly strongly expressed in extraglomerular mesangial cells but not in endothelial or intraglomerular mesangial cells. The selective expression of PrP(c) in podocytes is of special importance, as it suggests that these cells represent possible targets for peripheral infection with prions and demonstrates that PrP(c) can be added to the list of neuronal factors expressed in mammalian podocytes.

Cellular Prion Protein in the Bovine Mammary Gland Is Selectively Expressed in Active Lactocytes

“…This finding is in accordance with the reactivity of a rabbit antiserum raised against a slightly larger sequence (VEQMCITQYQRESQAY-YQR) of bovine PrP that also exhibited no isoform specificity (Takahashi et al 1999). Furthermore, applicability of this sandwich ELISA has been demonstrated in a previous study on cell-type-specific expression of PrP c in bovine kidney samples (Amselgruber et al 2006). Compared with the latter study, ELISA signals for mammary glands were relatively weak and indicated that for PrP c in this tissue the extraction efficacy of the applied method was low.…”

Quantitative and qualitative analysis of cellular prion protein (PrPC) expression in bovine somatic tissues

“…These observations confirm and extend the results of a previous report that indicated the presence of PrP C in bovine glomeruli. 39 Scrapie-infected hamsters and CJD patients have been shown to excrete PrP Sc in urine and PrP Sc has been detected in the collecting tubules of scrapieinfected hamsters that shed PrP Sc in urine. 40 While in principle the presence of PrP C in the bovine kidney may render it susceptible to prion infection, PrP Sc has not been detected in the urine of BSE-infected cattle 21 and to our knowledge, kidneys from BSE-infected cattle have not been evaluated for the presence of PrP Sc or BSE infectivity.…”

Occurrence and cellular localization of PrPd in kidneys of scrapie‐affected sheep in the absence of inflammation

“…Filtration of PrP d at the glomeruli would result in its presence in the urinary system and therefore explain its detection—and that of infectivity—in the urine 32. Such protein filtration could be enhanced following injury to podocytes, in which PrP c has been described 33, and disruption of the slit diaphragm, which would result in proteinuria as well as prionuria. Some of the PrP d filtered at the glomerular level could be reabsorbed at the bend of Henle's loops, where the osmotic pressure of the urine is at its highest, leading to accumulation in the papillary interstitium directly from the point of release or after amplification in infected fibroblasts.…”