Infection of human endothelial cells by Japanese encephalitis virus: increased expression and release of soluble HLA-E

• Published in: PloS one Vol. 8; no. 11; p. e79197
• Main Authors: Shwetank, Date, Onkar S, Kim, Kwang S, Manjunath, Ramanathapuram
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 13-11-2013; Public Library of Science (PLoS)
• Subjects: Antigens; Biochemistry; Brain; Cell culture; Cell cycle; Cell Line; Cell surface; Central nervous system; Children; Cytokines; Cytokines - biosynthesis; Cytokines - pharmacology; Double-stranded RNA; Encephalitis; Encephalitis Virus, Japanese - physiology; Endothelial cells; Endothelial Cells - immunology; Endothelial Cells - metabolism; Endothelial Cells - virology; Endothelium; Fibroblasts; Flavivirus; Gelatinase B; Gene Expression; Gene Expression Regulation - drug effects; Genes; Health aspects; Histocompatibility antigen HLA; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - immunology; Histocompatibility Antigens Class I - metabolism; HLA antigens; HLA-E Antigens; Humans; Immunophenotyping; Infections; Interferon-beta - biosynthesis; Interferon-beta - pharmacology; Japanese encephalitis; Kinases; Major histocompatibility complex; Matrix Metalloproteinase 9 - genetics; Matrix Metalloproteinase 9 - metabolism; Matrix metalloproteinases; Microvasculature; Neutralization; Polyinosinic:polycytidylic acid; Proteins; Ribonucleic acid; RNA; RNA viruses; Rodents; Shedding; Time Factors; Transcription, Genetic; Tumor necrosis factor; Tumor Necrosis Factor-alpha - biosynthesis; Tumor Necrosis Factor-alpha - pharmacology; Tumor necrosis factor-TNF; Tumor necrosis factor-α; Vector-borne diseases; Viral infections; Virus Release; Viruses; West Nile virus; β-Interferon; India
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0079197

Japanese encephalitis virus (JEV) is a single stranded RNA virus that infects the central nervous system leading to acute encephalitis in children. Alterations in brain endothelial cells have been shown to precede the entry of this flavivirus into the brain, but infection of endothelial cells by JEV and their consequences are still unclear. Productive JEV infection was established in human endothelial cells leading to IFN-β and TNF-α production. The MHC genes for HLA-A, -B, -C and HLA-E antigens were upregulated in human brain microvascular endothelial cells, the endothelial-like cell line, ECV 304 and human foreskin fibroblasts upon JEV infection. We also report the release/shedding of soluble HLA-E (sHLA-E) from JEV infected human endothelial cells for the first time. This shedding of sHLA-E was blocked by an inhibitor of matrix metalloproteinases (MMP). In addition, MMP-9, a known mediator of HLA solubilisation was upregulated by JEV. In contrast, human fibroblasts showed only upregulation of cell-surface HLA-E. Addition of UV inactivated JEV-infected cell culture supernatants stimulated shedding of sHLA-E from uninfected ECV cells indicating a role for soluble factors/cytokines in the shedding process. Antibody mediated neutralization of TNF-α as well as IFNAR receptor together not only resulted in inhibition of sHLA-E shedding from uninfected cells, it also inhibited HLA-E and MMP-9 gene expression in JEV-infected cells. Shedding of sHLA-E was also observed with purified TNF-α and IFN-β as well as the dsRNA analog, poly (I:C). Both IFN-β and TNF-α further potentiated the shedding when added together. The role of soluble MHC antigens in JEV infection is hitherto unknown and therefore needs further investigation.