Platelet activation and aggregation response to dengue virus nonstructural protein 1 and domains

Platelets are now recognized as immunological sentries in the first line of defense that participate in the detection and response to pathogens. This frequently results in a decrease in the number of circulating platelets. Different mechanisms have been hypothesized to explain the thrombocytopenia in patients with severe dengue, one of them is the participation of the non-structural protein 1 (NS1) of dengue virus (DENV), which can be secreted into circulation during DENV infection and promotes a more efficient infection.

The present study aimed to investigate the ability of platelet response to stimulation with full-length DENV NS1 protein and its domains.

DENV NS1 plasmid was transfected into HEK-293T. Proteins were purified by Niquel Sepharose affinity chromatography. Secreted proteins were assessed by sodium dodecylsulfate polyacrylamide gel electrophoresis, Coomassie staining and western blot. Platelet-rich plasma was directly incubated with DENV NS1 proteins. Platelet activation was confirmed by expression of αIIbβIII and P-selectin by flow cytometry. Platelet aggregation was also assessed using DENV NS1 protein and its individual domains as agonists.

DENV NS1 protein and its domains induce P-selectin and αIIbβ3 complex expression on platelet surfaces. DENV NS1 induce a stable platelet aggregation after the addition of a minimal dose of adenosine diphosphate (ADP), epinephrine (EPI), or collagen. Interestingly, only EPI could induce the formation of platelet aggregates after incubation with the protein domains of NS1.

Our results suggest that the full DENV NS1 protein and also its domains promote platelet recognition, activation, and aggregation.