Circulating extracellular vesicles are endowed with enhanced procoagulant activity in SARS-CoV-2 infection

Abstract

Background Coronavirus-2 (SARS-CoV-2) infection causes an acute respiratory syndrome accompanied by multi-organ damage that implicates a prothrombotic state leading to widespread microvascular clots. The causes of such coagulation abnormalities are unknown. The receptor tissue factor, also known as CD142, is often associated with cell-released extracellular vesicles (EV). In this study, we aimed to characterize surface antigens profile of circulating EV in COVID-19 patients and their potential implication as procoagulant agents. Methods We analyzed serum-derived EV from 67 participants who underwent nasopharyngeal swabs molecular test for suspected SARS-CoV-2 infection (34 positives and 33 negatives) and from 16 healthy controls (HC), as referral. A sub-analysis was performed on subjects who developed pneumonia ( n = 28). Serum-derived EV were characterized for their surface antigen profile and tested for their procoagulant activity. A validation experiment was performed pre-treating EV with anti-CD142 antibody or with recombinant FVIIa. Serum TNF-α levels were measured by ELISA. Findings Profiling of EV antigens revealed a surface marker signature that defines circulating EV in COVID-19. A combination of seven surface molecules (CD49e, CD209, CD86, CD133/1, CD69, CD142, and CD20) clustered COVID (+) versus COVID (-) patients and HC. CD142 showed the highest discriminating performance at both multivariate models and ROC curve analysis. Noteworthy, we found that CD142 exposed onto surface of EV was biologically active. CD142 activity was higher in COVID (+) patients and correlated with TNF-α serum levels. Interpretation In SARS-CoV-2 infection the systemic inflammatory response results in cell-release of substantial amounts of procoagulant EV that may act as clotting initiation agents, contributing to disease severity. Funding Cardiocentro Ticino Institute, Ente ospedaliero Cantonale, Lugano-Switzerland.

Extracellular Vesicles and Thrombosis: Update on the Clinical and Experimental Evidence

“…Notably, increased circulating EV numbers were already detectable in asymptomatic subjects diagnosed with COVID-19 [220]. Similar to other procoagulant states associated with endothelial or platelet activation, as outlined above, EVs in COVID-19 patients were shown to carry increased levels of biologically active TF [218,220,221] or PS [215] on their surface. However, and in contrast to patients with septic shock not related to COVID-19, TF-EV levels were markedly higher and paralleled by increased fibrinolytic activities not counterbalanced by increased PAI-1 [218], in line with the existence of a COVID-19 specific coagulopathy [212].…”

“…Others found elevated circulating numbers of CD41 + CD31 + platelet EVs to predict the presence of SARS-CoV-2 infection [219]. Notably, increased circulating EV numbers were already detectable in asymptomatic subjects diagnosed with COVID-19 [220]. Similar to other procoagulant states associated with endothelial or platelet activation, as outlined above, EVs in COVID-19 patients were shown to carry increased levels of biologically active TF [218,220,221] or PS [215] on their surface.…”

“…In addition to observations of elevated circulating EV numbers and their associations with disease severity, first studies reported a specific surface antigen signature [220] or protein cargo [222] in circulating EVs isolated from patients diagnosed with COVID-19. It also was speculated that changes in EV cargo in subgroups of COVID-19 patients, such as those with diabetes mellitus, obesity or hypertension, may contribute to the increased morbidity and mortality observed in these high-risk populations [223].…”

Role of Extracellular Vesicles in Cell Death and Inflammation

“…GM3-enriched exosomes were shown to be positively correlated with COVID-19 disease severity, suggesting they may partake in pathological processes related to COVID-19 pathogenesis [158]. In SARS-CoV-2 infection, the systemic inflammatory response was shown to result in the release of substantial amounts of procoagulant EVs that may act as clotting initiation agents, contributing to disease severity [121,122]. On the other hand, exosome-based strategies were also proposed to treat COVID-19 or prevent SARS-CoV-2 infection [120,123,159].…”

Procoagulant activity of extracellular vesicles in plasma of patients with SARS-CoV-2 infection

“…A report by Balbi and colleagues [8] shows that tissue factor (TF, CD142), a key initiator of the coagulation pathway, is present on the surface of circulating EVs in patients with SARS-CoV-2 infection.…”