Highly efficient intercellular spreading of protein misfolding mediated by viral ligand - receptor interactions
Pathological protein aggregates associated with neurodegenerative diseases have the ability to transmit to unaffected cells, thereby templating their own aberrant conformation onto soluble proteins of the same kind. Proteopathic seeds can be released into the extracellular space, secreted in association with extracellular vesicles (EV) or exchanged by direct cell-to-cell contact. The extent to which each of these pathways contributes to the prion-like spreading of protein misfolding is unclear. Exchange of cellular cargo by both direct cell-to-cell contact as well as via EV depends on receptor-ligand interactions and subsequent release of cargo into the cytosol. We hypothesized that enabling these interactions through viral ligands enhances the aggregate-inducing capacity of EV-associated proteopathic seeds. Using different cellular models propagating model prion-like protein aggregates, mouse-adapted prions or pathogenic Tau aggregates, we demonstrate that vesicular stomatitis virus glycoprotein and SARS-CoV-2 spike S increase protein aggregate induction by direct cell-to-cell contact or via viral glycoprotein-decorated EV. Thus, receptor-ligand interactions are major determinants of intercellular aggregate dissemination. Further, our data raise the intriguing possibility that acute or latent viral infections contribute to proteopathic seed spreading by facilitating intercellular cargo transfer. HIGHLIGHTSO_LIDifferent types of proteopathic seeds are secreted in association with extracellular vesicles C_LIO_LIReceptor-ligand interactions are important drivers of direct cell-to-cell and extracellular vesicle-mediated spreading of protein misfolding C_LIO_LIViral glycoproteins mediating attachment and membrane fusion strongly enhance aggregate inducing capacity in recipient cells C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=191 HEIGHT=200 SRC="FIGDIR/small/173070v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1735b86org.highwire.dtl.DTLVardef@7ddaf5org.highwire.dtl.DTLVardef@b222aborg.highwire.dtl.DTLVardef@1022dd6_HPS_FORMAT_FIGEXP M_FIG C_FIG