Platelet proteome analysis reveals an early hyperactive phenotype in SARS-CoV-2-infected humanized ACE2 mice

Abstract

Coronavirus disease-2019 (COVID-19) provokes a hypercoagulable state with increased incidence of thromboembolism and mortality. Platelets are major effectors of thrombosis and hemostasis. Suitable animal models are needed to better understand COVID-19-associated coagulopathy (CAC) and underlying platelet phenotypes. Here, we assessed K18-hACE2 mice undergoing a standardized SARS-CoV-2 infection protocol to study dynamic platelet responses via mass spectrometry-based proteomics. In total, we found significant changes in >1,200 proteins. Strikingly, protein alterations occurred rapidly by 2 days post-infection (dpi) and preceded outward clinical signs of severe disease. Pathway enrichment analysis of 2dpi platelet proteomes revealed that SARS-CoV-2 infection upregulated complement-coagulation networks (F2, F12, CFH, CD55/CD59), platelet activation-adhesion-degranulation proteins (PF4, SELP, PECAM1, HRG, PLG, vWF), and chemokines (CCL8, CXCL5, CXCL12). When mice started to lose weight at 4dpi, pattern recognition receptor signaling (RIG-I/MDA5, CASP8, MAPK3), and interferon pathways (IFIT1/IFIT3, STAT1) were predominant. Interestingly, SARS-CoV-2 spike protein in the lungs was observed by immunohistochemistry, but in platelets was undetected by proteomics. Similar to patients, K18-hACE2 mice during SARS-CoV-2 infection developed progressive lymphohistiocytic interstitial pneumonia with platelet aggregates in the lungs and kidneys. In conclusion, this model recapitulates activation of coagulation, complement, and interferon responses in circulating platelets, providing valuable insight into platelet pathology during COVID-19.

Aging is associated with an insufficient early inflammatory response of lung endothelial cells in SARS-CoV-2 infection

“…To explore age-related infection outcomes, we investigated the pathogenicity of SARS-CoV-2 in aged (85–112 weeks) and young (12–15 weeks) mice. Due to high lethality rates at 1x10 6 dose ( 21 , 37 ), an inoculation dose of 10 4 PFU of SARS-CoV-2 WA-1 was used for survival experiments. Survival studies revealed a significantly higher mortality rate in aged mice than young mice when challenged with SARS-CoV-2 ( Figure 1A ).…”

Does SARS-CoV-2 infect platelets?

“…Autopsies reported the presence of SARS-CoV-2 viral particles in both megakaryocytes and platelets (54). Notably, Zhang et al reported ACE2 expression on the platelet surface (55), but this observation was not consistently replicated in other studies (24,31,54,56). The conflicting findings raise questions about the interaction between SARS-CoV-2 and platelets through ACE2.…”