Biology subjects

Nyström, S.

Publications and source records attributed to Nyström, S..

2 recordsLinked to original sources

bioRxiv2025

SARS-CoV-2 spike protein amyloid fibrils impair fibrin formation and fibrinolysis

Long COVID, also known as post-acute sequelae of COVID-19 (PASC) from SARS-CoV-2 infection, is a debilitating and persistent disease of multiple systems and organs. WHO reports a total of 778 million registered SARS-CoV-2 infections as of June 2025. Recent studies indicate that as many as 25% of COVID patients will experience at least one symptom of Long COVID. Long COVID pathophysiology is a complex and not fully established process. One prevailing theory is that the formation of fibrin amyloid microclots (fibrinaloids), due to SARS-CoV-2 infection, can induce persistent inflammation and capillary blockage. An association between the amyloidogenic Spike protein of SARS-CoV-2 and impaired fibrinolysis has previously been made when it was observed that fibrin clots formed in the presence of a mixture of amyloid fibrils from the spike protein displayed a resistance to plasmin-mediated lysis. Here we investigated the molecular processes of impaired fibrinolysis using seven amyloidogenic SARS-COV-2 Spike peptides. Five out of seven Spike amyloid fibrils appeared not to substantially interfere with the fibrinogen-fibrin-fibrinolysis process in vitro, while two spike fibrils were active in different ways. Spike601 amyloid fibrils (sequence 601-620) impaired thrombin mediated fibrin formation by binding and sequestering fibrinogen but did not affect fibrinolysis. On contrary fibrin clots formed in the presence of Spike685 amyloid fibrils (sequence 685-701) exhibited a marked resistance to plasmin mediated fibrinolysis. We conclude that Spike685 amyloid fibrils can induce dense fibrin clot networks, as well as incorporate fibrin into aggregated structures that resist fibrinolysis. These results demonstrate how the Spike protein of SARS-CoV-2 could contribute to the formation fibrinolysis-resistant microclots observed in long COVID.

biochemistry↗

bioRxiv2023

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.

neuroscience↗