SARS-CoV-2 Spike amyloid fibrils specifically and selectively accelerates amyloid fibril formation of human prion protein and the amyloid β peptide

An increasing number of reports suggest an association between COVID-19 infection and initiation or acceleration of neurodegenerative diseases (NDs) including Alzheimers disease (AD) and Creutzfeldt-Jakob disease (CJD). Both these diseases and several other NDs are caused by conversion of human proteins into a misfolded, aggregated amyloid fibril state. The fibril formation process is self-perpetuating by seeded conversion from preformed fibril seeds. We recently described a plausible mechanism for amyloid fibril formation of SARS-CoV-2 spike protein. Spike-protein formed amyloid fibrils upon cleavage by neutrophil elastase, abundant in the inflammatory response to COVID-19 infection. We here provide evidence of significant Spike-amyloid fibril seeded acceleration of amyloid formation of CJD associated human prion protein (HuPrP) using an in vitro conversion assay. By seeding the HuPrP conversion assay with other in vitro generated disease associated amyloid fibrils we demonstrate that this is not a general effect but a specific feature of spike-amyloid fibrils. We also showed that the amyloid fibril formation of AD associated A{beta}1-42 was accelerated by Spike-amyloid fibril seeds. Of seven different 20-amino acid long peptides, Spike532 (532NLVKNKCVNFNFNGLTGTGV551) was most efficient in seeding HuPrP and Spike601 (601GTNTSNQVAVLYQDVNCTEV620) was most effective in seeding A{beta}1-42, suggesting substrate dependent selectivity of the cross-seeding activity. Albeit purely in vitro, our data suggest that cross-seeding by Spike-amyloid fibrils can be implicated in the increasing number of reports of CJD, AD, and possibly other NDs in the wake of COVID-19.