Measles Virus Infection Fosters Dendritic Cell Motility in a 3D Environment to Enhance Transmission to Target Cells in the Respiratory Epithelium.

Shaghayegh Derakhshani,Elita Avota,Maria Steinke,Markus Sauer,Fabian Schumacher,Lisa Pilgram,Andreas Kurz,Sibylle Schneider-Schaulies,Lukasz Japtok,Burkhard Kleuser

doi:10.3389/fimmu.2019.01294

Abstract

Transmission of measles virus (MV) from dendritic to airway epithelial cells is considered as crucial to viral spread late in infection. Therefore, pathways and effectors governing this process are promising targets for intervention. To identify these, we established a 3D respiratory tract model where MV transmission by infected dendritic cells (DCs) relied on the presence of nectin-4 on H358 lung epithelial cells. Access to recipient cells is an important prerequisite for transmission, and we therefore analyzed migration of MV-exposed DC cultures within the model. Surprisingly, enhanced motility toward the epithelial layer was observed for MV-infected DCs as compared to their uninfected siblings. This occurred independently of factors released from H358 cells indicating that MV infection triggered cytoskeletal remodeling associated with DC polarization enforced velocity. Accordingly, the latter was also observed for MV-infected DCs in collagen matrices and was particularly sensitive to ROCK inhibition indicating infected DCs preferentially employed the amoeboid migration mode. This was also implicated by loss of podosomes and reduced filopodial activity both of which were retained in MV-exposed uninfected DCs. Evidently, sphingosine kinase (SphK) and sphingosine-1-phosphate (S1P) as produced in response to virus-infection in DCs contributed to enhanced velocity because this was abrogated upon inhibition of sphingosine kinase activity. These findings indicate that MV infection promotes a push-and-squeeze fast amoeboid migration mode via the SphK/S1P system characterized by loss of filopodia and podosome dissolution. Consequently, this enables rapid trafficking of virus toward epithelial cells during viral exit.

Highlights

The ability of dendritic cells (DCs) to migrate through tissues is essential for an effective immune response
In contrast to the early phase, measles virus (MV) infection of respiratory tract epithelial cells is apparent at late infection stages: nectin-4, expressed on their basolateral surface as receptor becomes accessible to the virus [11, 12], and this is essential for efficient viral exit from this compartment and horizontal transmission [13, 14]
Formation of organized virological synapses between MV-infected DCs and T cells as important for transmission has been described, while transmission interfaces between MV-infected DCs and epithelial cells are less well-characterized [3, 21]. Though these studies suggested that infected DCs could serve as important viral donors both early and late in infection, their experimental setup did not allow to address the impact of MV-infection on DC migration which is of crucial importance and prerequisite for successful interaction with target cells and transmission

Summary

INTRODUCTION

The ability of DCs to migrate through tissues is essential for an effective immune response. In contrast to the early phase, MV infection of respiratory tract epithelial cells is apparent at late infection stages: nectin-4, expressed on their basolateral surface as receptor becomes accessible to the virus [11, 12], and this is essential for efficient viral exit from this compartment and horizontal transmission [13, 14]. Formation of organized virological synapses between MV-infected DCs and T cells as important for transmission has been described, while transmission interfaces between MV-infected DCs and epithelial cells are less well-characterized [3, 21] Though these studies suggested that infected DCs could serve as important viral donors both early and late in infection, their experimental setup did not allow to address the impact of MV-infection on DC migration which is of crucial importance and prerequisite for successful interaction with target cells and transmission. We established that the infectionregulated sphingosine kinase (SphK)/S1P system contributed to enhancement of infected DC migration in 3D which was amoeboid rather than mesenchymal-like as revealed by reduction of filopodial activity and detectable podosome structures

Ethics Statement

RESULTS

DISCUSSION