Dengue virus NS1 cytokine-independent vascular leak is dependent on endothelial glycocalyx components

Abstract

Dengue virus (DENV) is the most prevalent, medically important mosquito-borne virus. Disease ranges from uncomplicated dengue to life-threatening disease, characterized by endothelial dysfunction and vascular leakage. Previously, we demonstrated that DENV nonstructural protein 1 (NS1) induces endothelial hyperpermeability in a systemic mouse model and human pulmonary endothelial cells, where NS1 disrupts the endothelial glycocalyx-like layer. NS1 also triggers release of inflammatory cytokines from PBMCs via TLR4. Here, we examined the relative contributions of inflammatory mediators and endothelial cell-intrinsic pathways. In vivo, we demonstrated that DENV NS1 but not the closely-related West Nile virus NS1 triggers localized vascular leak in the dorsal dermis of wild-type C57BL/6 mice. In vitro, we showed that human dermal endothelial cells exposed to DENV NS1 do not produce inflammatory cytokines (TNF-α, IL-6, IL-8) and that blocking these cytokines does not affect DENV NS1-induced endothelial hyperpermeability. Further, we demonstrated that DENV NS1 induces vascular leak in TLR4- or TNF-α receptor-deficient mice at similar levels to wild-type animals. Finally, we blocked DENV NS1-induced vascular leak in vivo using inhibitors targeting molecules involved in glycocalyx disruption. Taken together, these data indicate that DENV NS1-induced endothelial cell-intrinsic vascular leak is independent of inflammatory cytokines but dependent on endothelial glycocalyx components.

Crocin alleviates lipopolysaccharide-induced acute respiratory distress syndrome by protecting against glycocalyx damage and suppressing inflammatory signaling pathways

“…Enzymes are a key factor in glycocalyx degradation. Glasner et al [9] reported that heparanase (HPA) and cathepsin L were connected with HS shedding in dengue virus non-structural protein 1-induced endothelial hyperpermeability. Reine et al [10] reported that matrix metalloproteinase 9 (MMP-9) was related to the degradation and shedding of SDC-4 in glomerular endothelial cells.…”

Insights from direct studies on human dengue infections

“…DENV NS1 disrupts the EGL in vitro through an activation of endothelial sialidases and the cathepsin L/heparanase pathway. Glycocalyx components, such as heparan sulfate and chondroitin sulfate, circulate at higher levels in the sera of DENV-infected patients as compared with healthy controls (28). These findings have profound implications for moderation of acute illness by use of agents that interrupt the EGL destruction cascade or prevent NS1-mediated dengue vascular permeability, possibly with a vaccine.…”

“…NS1 exacerbates an otherwise sublethal DENV infection. Cytokines may have no pathological role in vascular permeability, as a mouse model shows that circulation of NS1 alone leads to vascular permeability accompanied by significant increases in circulating levels of inflammatory cytokines (28). DENV NS1 disrupts the EGL in vitro through an activation of endothelial sialidases and the cathepsin L/heparanase pathway.…”

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

“…It has been reported NS1 can affect the complement pathway promoting the degradation of C4 protein, alters the coagulation system inhibiting the activation of prothrombin (reviewed by Conde et al, 2017). 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).…”