IL8 release, tight junction and cytoskeleton dynamic reorganization conducive to permeability increase are induced by dengue virus infection of microvascular endothelial monolayers

Abstract

Permeability alterations of microvascular endothelia may be a factor in the plasma leakage produced by dengue virus infection. Confluent monolayers of the human dermal microvascular endothelial cell line HMEC-1 were utilized as an experimental model to study the cellular responses induced by the virus. Infected monolayers showed increased permeability for [ 3 H]mannitol, but no changes were observed for 4-70 kDa dextrans at 48 h post-infection (p.i.), a time at which viral titres reached maximal values and 40 % of the cells expressed viral proteins. A further increase in permeability occurred at 72 h, still without evident cytopathic effects on the monolayer. Coinciding with this, actin was reorganized in the infected cells and the tight junction protein occludin was displaced to the cytoplasm. Increments in the thickness of stress fibres and focal adhesions were observed in uninfected cells neighbouring infected cells. Culture medium from infected monolayers induced permeability changes and thickening of actin-containing structures in control cultures that resembled those observed 48 h p.i. Interleukin (IL) 8 was found in culture medium at concentrations ranging from 20 to 100 pg ml "1 . Neutralizing antibodies against IL8 partially inhibited the changes produced by the culture medium as well as those induced by addition of IL8. Genistein inhibited the effect of the culture medium and the phosphorylation of proteins associated with focal adhesions and indicated the participation of tyrosine kinases. These findings suggest that IL8 production by infected monolayers contributes to the virus-induced effect on the cytoskeleton and tight junctions and thereby modifies transendothelial permeability.

Virus-Induced Decline in Soluble Vascular Endothelial Growth Receptor 2 Is Associated with Plasma Leakage in Dengue Hemorrhagic Fever

“…The correlation between plasma viral load and the subsequent decline in sVEGFR2 levels lend support to this in vitro finding. Previous studies have shown increased sensitivity of endothelial cells exposed to live dengue virus to inflammatory cytokine-induced changes in permeability (42). Our observations suggest a novel mechanism by which viral factors (or host factors triggered by virus) may regulate the cleavage of surface VEGFR2, resulting in changes in soluble and surface VEGF receptors and, consequently, changes in vascular permeability.…”

Transactivation of Vascular Endothelial Growth Factor Receptor-2 by Interleukin-8 (IL-8/CXCL8) Is Required for IL-8/CXCL8-induced Endothelial Permeability

“…The latter finding is particularly relevant for various pathological processes involving abnormal inflammation, angiogenesis, and/or endothelial permeability, as may occur during lung injury and tumorigenesis. As mentioned previously, IL-8 is known to play an important role in various pathological permeability events, such as those associated with lung injury (Fukumoto et al, 1998;Yamamoto et al, 1998;Laffon et al, 1999;Talavera et al, 2004). Likewise, VEGF is known to participate in lung injury-associated permeability; VEGF protein levels increase after lung injury (Karmpaliotis et al, 2002), and inhibition of VEGF signaling via soluble VEGFR2 decreased the associated permeability (Godzich et al, 2006).…”

“…This is particularly important when considering the known role of IL-8 in increasing endothelial permeability during pathological conditions (Fukumoto et al, 1998;Yamamoto et al, 1998;Laffon et al, 1999;Talavera et al, 2004). In addition, a more comprehensive understanding of the signal transduction pathways activated by IL-8 in endothelial cells may yield insight into angiogenesis, which is important in the growth and metastasis of melanoma and nonsmall cell lung cancer (Arenberg et al, 1996;Bar-Eli, 1999;Huang et al, 2002).…”

“…Although previous studies have investigated endothelial permeability and its associated mechanisms in response to various permeability inducers, the mechanisms involved in permeability induced by IL-8 remain unknown. Greater understanding of this process may give further insight into the role of IL-8 -induced permeability in various pathological situations characterized by excessive vascular permeability, because previous studies have demonstrated the importance of IL-8 in such conditions (Fukumoto et al, 1998;Yamamoto et al, 1998;Laffon et al, 1999;Talavera et al, 2004). Several therapeutic strategies are currently under consideration for the treatment of such pathologies, including neutralizing IL-8 antibodies, chemokine receptor antagonists, and broadspectrum chemokine inhibitors (Gebicke-Haerter et al, 2001;Grainger and Reckless, 2003).…”

Vitreous levels of interleukine-8 and monocyte chemoattractant protein-1 in macular oedema with branch retinal vein occlusion

“…22 In another study, addition of IL-8 to monolayers of the human dermal microvascular endothelial cell line HMEC-1 caused changes in tight junction structure; the changes were inhibited by IL-8 antibodies. 23 The role of IL-8 and MCP-1 in eye disease has also been investigated. In vitro expression and production of IL-8 and MCP-1 by human retinal endothelial cells and HRPE after stimulation by pro-inflammatory cytokines have been reported.…”