Influenza A virus infection of vascular endothelial cells induces GSK-3β-mediated β-catenin degradation in adherens junctions, with a resultant increase in membrane permeability.

M Hiyoshi,H Kido,M Yano,I L Indalao,K Yamane,E Takahashi

doi:10.1007/s00705-014-2270-5

Abstract

Multiorgan failure with vascular hyperpermeability is the final outcome in the progression of seasonal influenza virus pneumonia and influenza-associated encephalopathy, and it is also common in infection with highly pathogenic avian influenza virus. However, the precise molecular mechanism by which influenza virus infection causes vascular endothelial cell hyperpermeability remains poorly defined. We investigated the mechanisms of hyperpermeability of human umbilical vein endothelial cells infected with influenza A virus (IAV)/Puerto Rico/8/34 (PR8) (H1N1). The levels of β-catenin, a key regulatory component of the vascular endothelial-cadherin cell adhesion complex, were markedly decreased during infection for 28 h, with increments of vascular hyperpermeability measured by transendothelial electrical resistance. Lactacystin (at 2 μM), a proteasome inhibitor, inhibited the decrease in β-catenin levels. Since the N-terminal phosphorylation of β-catenin by glycogen synthase kinase (GSK)-3β is the initiation step of proteasome-dependent degradation, we examined the effects of GSK-3β suppression by RNA interference in endothelial cells. IAV-infection-induced β-catenin degradation was significantly inhibited in GSK-3β-knockdown cells, and transfection of cells with recombinant β-catenin significantly suppressed IAV-induced hyperpermeability. These findings suggest that IAV infection induces GSK-3β-mediated β-catenin degradation in the adherens junctional complexes and induces vascular hyperpermeability. The in vitro findings of β-catenin degradation and activation of GSK-3β after IAV infection were confirmed in lungs of mice infected with IAV PR8 during the course of infection from day 0 to day 6. These results suggest that GSK-3β-mediated β-catenin degradation in adherens junctions is one of the key mechanisms of vascular hyperpermeability in severe influenza.

Highlights

Influenza A virus (IAV) is the most common infectious pathogen in humans and causes significant morbidity and mortality, in infants and the elderly population [1, 2]
Multiorgan failure with vascular hyperpermeability is the final outcome in the progression of seasonal influenza virus pneumonia and influenza-associated encephalopathy, and it is common in infection with highly pathogenic avian influenza virus
Multiorgan failure (MOF) with vascular hyperpermeability is reported in the progressive stage of seasonal influenza virus pneumonia, in patients with underlying risk factors [3], and is common in infections caused by highly pathogenic avian influenza virus [4]

Summary

Introduction

Influenza A virus (IAV) is the most common infectious pathogen in humans and causes significant morbidity and mortality, in infants and the elderly population [1, 2]. Vascular hyperpermeability caused by destruction of a tight junction constituent, zonula occludens-1 (ZO)-1, of the blood-brain-barrier (BBB) in brain endothelial cells is reported in influenza-associated encephalopathy in infancy and early childhood in East Asians [5,6,7,8]. IAV infection induces upregulation of trypsin and matrix metalloprotease-9 through an ‘‘influenza–cytokine–protease’’ cycle in various organs and vascular endothelial cells [8, 9, 11, 12], and an increase in the levels of these proteases in the extracellular space caused by this cycle results in the degradation of vascular basement membranes and the extracellular matrix, resulting in vascular hyperpermeability and inflammatory cell migration. We found that GSK-3bmediated b-catenin degradation in the VE-cadherin complex in the adherens junction of human endothelial cells was associated with increased hyperpermeability after IAV infection

Materials and methods

Results

Discussion