Dengue Virus Nonstructural Protein 1 Induces Vascular Leakage through Macrophage Migration Inhibitory Factor and Autophagy

PLoS Negl Trop Dis. 2016 Jul 13;10(7):e0004828. doi: 10.1371/journal.pntd.0004828. eCollection 2016 Jul.

Abstract

Dengue virus (DENV) is the most common mosquito-borne flavivirus; it can either cause mild dengue fever or the more severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). One of the characteristic features of DHF/DSS is vascular leakage; although DENV nonstructural protein 1 (NS1) has been proved to induce vascular leakage after binding to Toll-like receptor 4, the down-stream mechanism has not yet been fully understood. In the sera of DENV-infected patients, the concentrations of DENV NS1 and inflammatory cytokine macrophage migration inhibitory factor (MIF) are positively correlated with disease severity, but whether DENV NS1 induces vascular leakage through MIF secretion remains unknown. We demonstrated that recombinant NS1 induced vascular leakage and MIF secretion both in human endothelial cell line HMEC-1 and in mice. Furthermore, these phenomena were inhibited in the presence of anti-NS1 antibodies both in vitro and in vivo. DENV NS1 also induced LC3-I to LC3-II conversion and p62 degradation in endothelial cell line, which indicated the formation of autophagy. To clarify whether MIF or autophagy mediated DENV NS1-induced vascular leakage, various inhibitors were applied. The results showed that DENV NS1-induced vascular leakage and VE-cadherin disarray were blocked in the presence of MIF inhibitors, anti-MIF-antibodies or autophagy inhibitors. An Atg5 knockdown clone further confirmed that autophagy formation of endothelial cells was required in NS1-induced vascular leakage. Furthermore, DENV NS1-induced LC3 puncta were also decreased in the presence of MIF inhibitors, indicating that MIF mediated DENV NS1-induced autophagy. Taken together, the results suggest a potential mechanism of DENV-induced vascular leakage and provide possible therapeutic targets against DHF/DSS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral
  • Autophagy / physiology*
  • Capillary Permeability
  • Cell Line
  • Dengue Virus / physiology*
  • Endothelium, Vascular
  • Humans
  • Macrophage Migration-Inhibitory Factors / antagonists & inhibitors
  • Macrophage Migration-Inhibitory Factors / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Viral Nonstructural Proteins / physiology*

Substances

  • Antibodies, Viral
  • Macrophage Migration-Inhibitory Factors
  • Viral Nonstructural Proteins

Grant support

This study was supported by grants from Ministry of Science and Technology of Taiwan (102-2320-B-006-025-MY3)(105-2321-B-006-023-) and the Center of Infectious Disease and Signaling Research of NCKU, Tainan, Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.