Avaliação da replicação do vírus da Dengue-2 em um modelo de interação plaqueta-monócito

Abstract

Dengue is an arbovirus disease transmitted by Aedes mosquitoes and is considered a global health problem. It has already been described that dengue virus (DENV) is capable of infecting cells such as monocytes, macrophages, dendritic, endothelial, and liver cells. It is known that platelets are capable of internalize, translate, and replicate DENV genome. However, our group and others have demonstrated that replication in platelets is abortive. Platelets from dengue patients are more activated and apoptotic when compared to healthy volunteers’ cells, and there is an increase in platelet-monocyte aggregates. Platelets from DENV-patients or infected with DENV in vitro secrete inflammatory mediators such as PF4, RANTES, IL1β and MIF, and show increased expression of P-selectin and phosphatidylserine on their surface. These signals modulates the interaction with monocytes and the inflammatory response. DENV-infected platelets incubated with monocytes from healthy volunteers induce the secretion of cytokines such as IL-8, MCP-1, IL-10 and IL-6 in monocytes. Although replication in platelets is abortive, we hypothesize that during platelet-monocyte interaction, platelets would be able to transfer the newly synthesized viral RNA to monocytes, which may continue the virus' replication cycle. We also questioned whether the platelet-monocyte interaction and the transfer of viral RNA could lead to inflammatory response modulation in monocytes through the recognition of dsRNa by endosomal TLRs and cytosolic sensors. This project aims to evaluate whether platelets can transfer the viral genome and/or modulate the inflammatory response of monocytes, and through which receptors it occurs. Our results demonstrate that platelets are capable of transferring the DENV genome to primary monocytes in vitro. Furthermore, the recognition of the viral RNA from infected platelets in monocytes induces increased IL-8 and MCP-1 secretion in cocultures, which is reduced by blocking the downstream pathway of RIG-I/MDA-5, but not of endosomal TLRs. However, the transfer of DENV RNA to monocytes does not occur in such a way that they are capable of generating new infectious viral particles.