NR AXIS
AU Barenco,M.G.; Tasciotti,V.; Mattei,V.; Casella,A.R.; Löwer,J.; Sorice,M.; Montrasio,F.
TI Plasma Membrane Released Microvesicles as Carriers of Infectious Prions
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.03
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Microvesicles (MVs) are submicron elements that are shed from the plasma membrane of most eukaryotic cells undergoing activation or apoptosis. The segregation of specific proteins is followed by blebbing of the membrane surface, leading to the formation of MVs and their release in the extracellular environment. The functional role of MVs is still largely unknown. However, a lot of evidence shows that they participate in a variety of intercellular adhesion processes and are able to induce cellular response(s). It has been previously shown that both PrPc and PrPsc are present in cell culture supernatants in a secreted, exosome-associated form and that exosomes bearing PrPsc are infectious both in vitro and in vivo.
The aim of this study was to evaluate the presence of PrPc in MVs from human plasma and the ability of neuronal cells to release MVs bearing PrPc, hypothesizing a possible role for these structures in the mechanism of PrPc diffusion and prion neuroinvasion. Furthermore, we investigated the capability of MVs derived from prion infected N2a PK1 cells in transmitting prion infection in vitro.
Here, we show that PrPc is a component of a multimolecular complex within microvesicle microdomains in human plasma. Moreover, we demonstrate that neuroblastoma N2a PK1 cells release MVs in cell culture supernatants, indicating that neuronal cells are able to shed MVs. Electron microscopy and/or immunoblot analyses showed that the isolated MVs express both PrPc and the axonal membrane protein Gap-43. We further demonstrate that MVs from RML-infected N2a PK1 cells carry PrPsc, as shown by the detection of Proteinase K-resistant PrP. In vitro infection experiments clearly showed that PrPsc-bearing MVs are capable of transmitting prion infectivity to recipient non-infected cell, which then replicate prions up to 30 passages after challenge.
Thus, release of microvesicles-associated PrPsc by infected cells, in addition to cell-cell contact, could be considered as an acellular mechanism underlying the spread of prions.
AD M.G. Barenco, J. Löwer, F. Montrasio, Paul-Ehrlich-Institute, Prion Research Group, Germany; V. Tasciotti, V. Mattei, A.R. Casella, M. Sorice, Department of Experimental Medicine, Italy
SP englisch
PO Schottland