Japanese encephalitis virus-associated human microglia induce cell death of human microvascular endothelial cells in receptor-independent infection

Isabelle Fellay ¹ Pauline Blanc ² Alexey Larionov ¹ Léa Schlunke ^1,3 Luis Filgueira ⁴ Nils Lannes ^1*

• ¹ Department of Oncology, Microbiology and Immunology, Unit of Anatomy, Faculty of Science and Medicine, Université de Fribourg, Fribourg, Switzerland
• ² Université de Fribourg, Fribourg, Switzerland
• ³ Laboratory of Microbiology and Microtechnology, School of Life Sciences (SV), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
• ⁴ Department of Oncology, Microbiology and Immunology, Unit of Anatomy, Université de Fribourg, Fribourg, Switzerland

The neurotropic virus Japanese encephalitis virus invades the human central nervous system, inducing neuroinflammation and further disruption of the blood-brain barrier. JEV interacts with various cell types of the blood-brain barrier including the endothelial cells. The present works aims to investigate impact in receptor-dependent and independent infection of human microvascular endothelial cells by Japanese encephalitis virus. Receptor-dependent infection was achieved using cell-free virus while receptor-independent infection was by co-culture of microvascular endothelial cells with virus-associated microglia. While both receptor-dependent and independent infections of human microvascular endothelial cells led to virus propagation, only receptor-independent infection induced cell death of human microvascular endothelial cells. While the CX3CR1-CX3CL1 axis was inefficient in blocking virus rescue and protecting endothelial cell from cell death, transcriptomics analysis identified Tumour Necrosis Factorrelated apoptosis inducing ligand and receptors as potential key player leading to endothelial cell death. Overall, our findings demonstrate that human microvascular endothelial cells supply virus propagation and Japanese encephalitis virus-associated microglia greatly contribute to endothelial cell death, an important component of the blood brain barrier integrity. Importantly, Tumour Necrosis Factor-related apoptosis inducing ligand and receptors represents a promising therapeutic target preventing microvascular endothelial cell death after neuroinvasion.