Dengue virus NS1 enhances viral replication and pro-inflammatory cytokine production in human dendritic cells

Abstract

Dengue virus (DV) has become the most prevalent arthropod borne virus due to globalization and climate change. It targets dendritic cells during infection and leads to production of pro-inflammatory cytokines and chemokines. Several DV non-structural proteins (NS) modulate activation of human dendritic cells. We investigated the effect of DV NS1 on human monocyte- derived dendritic cells (mo-DCs) during dengue infection. NS1 is secreted into the serum of infected individuals where it interacts with various immune mediators and cell types. We purified secreted DV1 NS1 from supernatants of 293T cells that over-express the protein. Upon incubation with mo-DCs, we observed NS1 uptake and enhancement of early DV1 replication. As a consequence, mo-DCs that were pre-exposed to NS1 produced more pro-inflammatory cytokines in response to subsequent DV infection compared to DCs exposed to heat-inactivated NS1 (HNS1). Therefore the presence of exogenous NS1 is able to modulate dengue infection in mo-DCs.

The dengue virus non-structural protein 1 (NS1) use the scavenger receptor B1 as cell receptor in human hepatic and mosquito cells

“…The viral titer did not experience a significant increase in cells pre-incubated with 3.5 ug/mL or 7 ug/mL of NS1, perhaps due to a saturation of the system. This result suggests that exposure and internalization of NS1 by C6/36 cells before viral infection favors viral particles production, in agreement with previous results reported for liver and dendritic cells (Alcon-Le Poder et al, 2005; Alayli and Scholle, 2016).…”

“…It is well established that DENV NS1 is internalized in human hepatic and dendritic cells, rendering the cells more susceptible to DENV infection (Alcon-LePoder et al, 2005; Alayli and Scholle, 2016); yet internalization of DENV NS1 in mosquito cells or of ZIKV NS1 in any cell type have not been reported. Thus, using Huh-7 liver cells in parallel, we evaluated if DENV and ZIKV NS1 were also internalized by C6/36 mosquito cells after 1 or 2 hours of incubation.…”

“…NS1 is the only flaviviral nonstructural protein secreted together with the viral particles toward the extracellular milieu from infected vertebrate and insect cells in high concentrations (up to μg/mL) (Flamand et al, 1999; Alcala et al, 2016). In fact, NS1 is used as an early marker for DENV and ZIKV detection from patient serum samples (reviewed in De la Cruz Hernández et al, 2013). The DENV, soluble circulating NS1 has been involved in several pathogenic mechanisms during the infection process.…”

“…NS1 can also disrupts endothelium integrity, promoting an increase in the vascular permeability after internalization by endocytosis, that may be related to plasma leakage (Glasner et al, 2017; Puerta-Guardo et al, 2019; Wang et al, 2019). Moreover, pre-exposure of human liver or dendritic cells to NS1 renders these cells more susceptible to DENV replication (Alcon-LePoder et al, 2005; Alayli and Scholle, 2016). Thus, a better understanding of the DENV soluble NS1- cell interactions may result in strategies to combat DENV replication and pathogenesis.…”

Dengue Virus NS1 Protein as a Diagnostic Marker: Commercially Available ELISA and Comparison to qRT-PCR and Serological Diagnostic Assays Currently Used by the State of Florida

“…At the time of FDA approval for the particular study, the test was already in use in approximately 40 countries around the world [20]. The USNIH notes on https://www.clinicaltrials.gov that the study has been completed but official results are yet to be reported [21]. In Lima et al [22], two of the previously mentioned assays, the PanBio ELISA and the Platelia™ EIA, were compared against another immunoassay, the Dengue NS1 STRIP (Bio-Rad, Hercules, CA).…”