DENV-2 Infection and Dengue Virus NS1 Stimulation Induce the Secretion of Inflammatory Mediators by Platelets

Introduction: Dengue is a disease that occurs mainly in tropical and subtropical regions, affecting thousands of people annually. Platelets play important roles in dengue pathogenesis, with thrombocytopenia being a major clinical marker. Beyond hemostasis, activated platelets participate in immune responses by expressing adhesion molecules and secreting mediators that modulate vascular and immune functions. This study investigated platelet secretion of RANTES/CCL5, TGF-β, sCD40L, and VEGF following stimulation with dengue virus non-structural protein 1 (NS1) or dengue virus serotype 2 (DENV-2). Methods: Platelets isolated from healthy donors (IRB: UFJF 7.809.410) were stimulated with NS1 (0.5, 5, or 50 µg/mL) for 1.5, 3, or 6 hours. Supernatants were collected after stimulation, and mediator secretion was quantified by Enzyme-Linked Immunosorbent Assay (ELISA). Similarly, isolated platelets were infected with DENV-2 (MOI=1) for 3, 6, or 24 hours, followed by supernatant collection and ELISA. Results and Discussion: NS1 at 50 µg/mL induced TGF-β secretion after 3 hours, whereas sCD40L secretion was not detected. sCD40L was induced only by thrombin (0.5 U/mL), used as a positive control. DENV-2 infection induced secretion of RANTES/CCL5 at 3 hours, TGF-β at 3 and 6 hours, sCD40L at 3 and 24 hours, and VEGF at 3, 6, and 24 hours post-infection. Conclusion: Both NS1 and DENV-2 are capable of activating platelets and inducing inflammatory mediator secretion, but DENV-2 induces a broader and more sustained secretory response.