scholarly journals Early Events in Japanese Encephalitis Virus Infection: Viral Entry

Pathogens ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 68 ◽  
Author(s):  
Sang-Im Yun ◽  
Young-Min Lee
Keyword(s):  
Cell Surface ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Clinical Manifestations ◽  
Encephalitis Virus ◽  
Host Cells ◽  
Target Cells ◽  
Major Public Health Problem ◽  
Viral Glycoprotein ◽  
Positive Strand Rna

Japanese encephalitis virus (JEV), a mosquito-borne zoonotic flavivirus, is an enveloped positive-strand RNA virus that can cause a spectrum of clinical manifestations, ranging from mild febrile illness to severe neuroinvasive disease. Today, several killed and live vaccines are available in different parts of the globe for use in humans to prevent JEV-induced diseases, yet no antivirals are available to treat JEV-associated diseases. Despite the progress made in vaccine research and development, JEV is still a major public health problem in southern, eastern, and southeastern Asia, as well as northern Oceania, with the potential to become an emerging global pathogen. In viral replication, the entry of JEV into the cell is the first step in a cascade of complex interactions between the virus and target cells that is required for the initiation, dissemination, and maintenance of infection. Because this step determines cell/tissue tropism and pathogenesis, it is a promising target for antiviral therapy. JEV entry is mediated by the viral glycoprotein E, which binds virions to the cell surface (attachment), delivers them to endosomes (endocytosis), and catalyzes the fusion between the viral and endosomal membranes (membrane fusion), followed by the release of the viral genome into the cytoplasm (uncoating). In this multistep process, a collection of host factors are involved. In this review, we summarize the current knowledge on the viral and cellular components involved in JEV entry into host cells, with an emphasis on the initial virus-host cell interactions on the cell surface.

scholarly journals Mosquito defensins enhance Japanese encephalitis virus infection by facilitating virus adsorption and entry within mosquito

2020 ◽  
Author(s):  
Ke Liu ◽  
Changguang Xiao ◽  
Shumin Xi ◽  
Muddassar hameed ◽  
Abdul Wahaab ◽  
...  
Keyword(s):  
Cell Surface ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Target Cells ◽  
The Novel ◽  
Antiviral Protein ◽  
Japanese Encephalitis Virus Infection ◽  
Virus Adsorption ◽  
Lipoprotein Receptor Related Protein

AbstractJapanese encephalitis virus (JEV) is a viral zoonosis which can cause viral encephalitis, death and disability. Culex is the main vector of JEV, but little is known about JEV transmission by this kind of mosquito. Here, we found that mosquito defensin facilitated the adsorption of JEV on target cells via both direct and indirect pathways. Mosquito defensin bound the ED III domain of viral E protein and directly mediated efficient virus adsorption on the target cell surface, Lipoprotein receptor-related protein 2 expressed on the cell surface is the receptor affecting defensin dependent adsorption. Mosquito defensin also indirectly down-regulated the expression of an antiviral protein, HSC70B. As a result, mosquitos defensin enhances JEV infection in salivary gland while increasing the possibility of viral transmission by mosquito. These findings demonstrate that the novel effects of mosquito defensin in JEV infection and the mechanisms through which the virus exploits mosquito defensin for infection and transmission.

scholarly journals Mosquito Defensins Enhance Japanese Encephalitis Virus Infection by Facilitating Virus Adsorption and Entry within the Mosquito

2020 ◽  
Vol 94 (21) ◽  
Author(s):  
Ke Liu ◽  
Changguang Xiao ◽  
Shumin Xi ◽  
Muddassar Hameed ◽  
Abdul Wahaab ◽  
...  
Keyword(s):  
Cell Surface ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Target Cells ◽  
Lipoprotein Receptor ◽  
Related Protein ◽  
E Protein ◽  
Virus Adsorption ◽  
Lipoprotein Receptor Related Protein

ABSTRACT Japanese encephalitis virus (JEV) is a viral zoonosis that can cause viral encephalitis, death, and disability. Although the Culex mosquito is the primary vector of JEV, little is known about JEV transmission by this kind of mosquito. Here, we found that mosquito defensin facilitated the adsorption of JEV on target cells via the defensin/lipoprotein receptor-related protein 2 (LRP2) axis. Mosquito defensin bound the ED III domain of the viral envelope (E) protein and directly mediated efficient virus adsorption on the target cell surface; the receptor LRP2, which is expressed on the cell surface, affected defensin-dependent adsorption. As a result, mosquito defensin enhanced JEV infection in the salivary gland, increasing the possibility of viral transmission by mosquitoes. These findings demonstrate the novel role of mosquito defensin in JEV infection and the mechanisms through which the virus exploits mosquito defensin for infection and transmission. IMPORTANCE In this study, we observed the complex roles of mosquito defensin in JEV infection; mosquito defensin exhibited a weak antiviral effect but strongly enhanced binding. In the latter, defensin directly binds the ED III domain of the viral E protein and promotes the adsorption of JEV to target cells by interacting with lipoprotein receptor-related protein 2 (LRP2), thus accelerating virus entry. Together, our results indicate that mosquito defensin plays an important role in facilitating JEV infection and potential transmission.

scholarly journals TIM-1 Promotes Japanese Encephalitis Virus Entry and Infection

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 630 ◽  
Author(s):  
Jichen Niu ◽  
Ya Jiang ◽  
Hao Xu ◽  
Changjing Zhao ◽  
Guodong Zhou ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Point Mutation ◽  
Japanese Encephalitis ◽  
Virus Entry ◽  
A549 Cells ◽  
Binding Pocket ◽  
Cytoplasmic Domain ◽  
Encephalitis Virus ◽  
Host Cells ◽  
Attachment Factor

Japanese encephalitis virus (JEV) is a mosquito-borne Flavivirus, the leading cause of viral-induced encephalitis. Several host molecules have been identified as the JEV attachment factor; however, the molecules involved in JEV entry remain poorly understood. In the present study, we demonstrate that TIM-1 is important for efficient infection by JEV. Firstly, three TIM-1 variants (V1, V2, and V3) were cloned from A549 cells, and we revealed that only ectopically TIM-1 V2 expression in 293T cells significantly promotes JEV attachment, entry and infection. Point mutation of phosphatidylserine (Ptdser) binding pocket in the TIM-1 IgV domain dampened JEV entry, indicating that TIM-1-mediated JEV infection is Ptdser-dependent. Furthermore, we found the cytoplasmic domain of TIM-1 is also required for enhancing JEV entry. Additionally, knock down of TIM-1 expression in A549 cells impaired JEV entry and infection, but not attachment, suggesting that additional factors exist in A549 cells that allow the virus to bind. In conclusion, our findings demonstrate that TIM-1 promotes JEV infection as an entry cofactor, and the polymorphism of TIM-1 is associated with JEV susceptibility to host cells.

scholarly journals Review of Emerging Japanese Encephalitis Virus: New Aspects and Concepts about Entry into the Brain and Inter-Cellular Spreading

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 111 ◽  
Author(s):  
Filgueira ◽  
Lannes
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Human Case ◽  
Encephalitis Virus ◽  
The Body ◽  
Host Cells ◽  
Asia Pacific ◽  
Latently Infected ◽  
The Impact ◽  
The Brain

Japanese encephalitis virus (JEV) is an emerging flavivirus of the Asia-Pacific region. More than two billion people live in endemic or epidemic areas and are at risk of infection. Recently, the first autochthonous human case was recorded in Africa, and infected birds have been found in Europe. JEV may spread even further to other continents. The first section of this review covers established and new information about the epidemiology of JEV. The subsequent sections focus on the impact of JEV on humans, including the natural course and immunity. Furthermore, new concepts are discussed about JEV’s entry into the brain. Finally, interactions of JEV and host cells are covered, as well as how JEV may spread in the body through latently infected immune cells and cell-to-cell transmission of virions or via other infectious material, including JEV genomic RNA.

scholarly journals Effect of brefelidin A and monensin on Japanese encephalitis virus maturation and virus release from cells

2011 ◽  
Vol 2 (1) ◽  
pp. 9
Author(s):  
Vaibhavi Jawahar Lad ◽  
Ashok Kumar Gupta
Keyword(s):  
Cell Surface ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Golgi Complex ◽  
Protein Transport ◽  
Virus Assembly ◽  
Brefeldin A ◽  
Antigen Expression ◽  
Encephalitis Virus ◽  
The Individual

Japanese encephalitis virus (JEV) replicates in a variety of cells, the exact intracellular site of virus assembly is somewhat obscure. The aims of this study were to investigate the role Golgi apparatus in JEV maturation by utilizing two Golgi-disrupting agents- brefeldin A (BFA) and monensin (MN) that inhibit virus assembly at specific cellular sites. JEV-infected porcine kidney stable (PS) cells were treated with BFA (2 ug/ mL) or MN (10 uM/ mL) at different h post-infection (p. i.) and the virus contents were assayed after 48 h p. i. The treated cells were further subjected to immuno-fluorescence (IF) using antibodies directed against JEV envelope glycoprotein (gpE) for localization of intracellular viral antigen as well as the antigen expression on the cell surface. Addition of BFA or MN to cells immediately after virus adsorption or at 4 h and 12 h postinfection (p. i.), resulted in 4- or 8- fold reduction in infectious virus contents along with inhibition of its transport to the cell surface, indicating an essential role of the Golgi-associated membranes in JEV replication. Interestingly, the antigenicity of the virus, in contrast, remained unaffected as no difference in epitope presentation/ expression was observed in BFA/MN-treated and control (untreated) infected cells even though in the former cells a loss of hemagglutinating (HA) activity was observed. Further, BFA addition at 18 h or 24 h p. i. showed only a negligible effect on virus suggesting that once the viral-associated membranes are formed, these membranes appear to be stable. In contrast, the inhibition with MN persisted even after its addition to cells at 18 h and 24 h p. i., indicating its sustained effect on JEV. Although BFA inhibits protein transport from endoplasmic reticulum (ER) to the Golgi complex while MN inhibits transport from medial to trans cisternae of the Golgi complex, none of the two agents however affected the gpE synthesis and folding essentially required for the epitope presentation/expression within the cells. As flaviviruses are known to encode three glycoproteins (gps) within their genomes i. e., prM, E, and NS, it will be worthwhile in future to determine whether vesicular transport occurs within or between the virus-induced membranes and how the individual JEV-encoded proteins are transported to discrete compartments further remain to be seen.

scholarly journals 3′ cis-Acting Elements That Contribute to the Competence and Efficiency of Japanese Encephalitis Virus Genome Replication: Functional Importance of Sequence Duplications, Deletions, and Substitutions

2009 ◽  
Vol 83 (16) ◽  
pp. 7909-7930 ◽  
Author(s):  
Sang-Im Yun ◽  
Yu-Jeong Choi ◽  
Byung-Hak Song ◽  
Young-Min Lee
Keyword(s):  
Viral Replication ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Rna Replication ◽  
Encephalitis Virus ◽  
Protein Accumulation ◽  
Genomic Rna ◽  
Human Neuroblastoma ◽  
Lethal Mutant ◽  
Positive Strand Rna

ABSTRACT The positive-strand RNA genome of Japanese encephalitis virus (JEV) terminates in a highly conserved 3′-noncoding region (3′NCR) of six domains (V, X, I, II-1, II-2, and III in the 5′-to-3′ direction). By manipulating the JEV genomic RNA, we have identified important roles for RNA elements present within the 574-nucleotide 3′NCR in viral replication. The two 3′-proximal domains (II-2 and III) were sufficient for RNA replication and virus production, whereas the remaining four (V, X, I, and II-1) were dispensable for RNA replication competence but required for maximal replication efficiency. Surprisingly, a lethal mutant lacking all of the 3′NCR except domain III regained viability through pseudoreversion by duplicating an 83-nucleotide sequence from the 3′-terminal region of the viral open reading frame. Also, two viable mutants displayed severe genetic instability; these two mutants rapidly developed 12 point mutations in domain II-2 in the mutant lacking domains V, X, I, and II-1 and showed the duplication of seven upstream sequences of various sizes at the junction between domains II-1 and II-2 in the mutant lacking domains V, X, and I. In all cases, the introduction of these spontaneous mutations led to an increase in RNA production that paralleled the level of protein accumulation and virus yield. Interestingly, the mutant lacking domains V, X, I, and II-1 was able to replicate in hamster BHK-21 and human neuroblastoma SH-SY5Y cells but not in mosquito C6/36 cells, indicating a cell type-specific restriction of its viral replication. Thus, our findings provide the basis for a detailed map of the 3′ cis-acting elements in JEV genomic RNA, which play an essential role in viral replication. They also provide experimental evidence for the function of 3′ direct repeat sequences and suggest possible mechanisms for the emergence of these sequences in the 3′NCR of JEV and perhaps in other flaviviruses.

scholarly journals Rab5 and Rab11 Are Required for Clathrin-Dependent Endocytosis of Japanese Encephalitis Virus in BHK-21 Cells

2017 ◽  
Vol 91 (19) ◽  
Author(s):  
Chun-Chun Liu ◽  
Yun-Na Zhang ◽  
Zhao-Yao Li ◽  
Jin-Xiu Hou ◽  
Jing Zhou ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Drug Targets ◽  
Encephalitis Virus ◽  
Dominant Negative ◽  
Endocytic Pathway ◽  
Host Cells ◽  
Rab Proteins ◽  
Endosomal Trafficking ◽  
Rab Gtpases

ABSTRACT During infection Japanese encephalitis virus (JEV) generally enters host cells via receptor-mediated clathrin-dependent endocytosis. The trafficking of JEV within endosomes is controlled by Rab GTPases, but which Rab proteins are involved in JEV entry into BHK-21 cells is unknown. In this study, entry and postinternalization of JEV were analyzed using biochemical inhibitors, RNA interference, and dominant negative (DN) mutants. Our data demonstrate that JEV entry into BHK-21 cells depends on clathrin, dynamin, and cholesterol but not on caveolae or macropinocytosis. The effect on JEV infection of dominant negative (DN) mutants of four Rab proteins that regulate endosomal trafficking was examined. Expression of DN Rab5 and DN Rab11, but not DN Rab7 and DN Rab9, significantly inhibited JEV replication. These results were further tested by silencing Rab5 or Rab11 expression before viral infection. Confocal microscopy showed that virus particles colocalized with Rab5 or Rab11 within 15 min after virus entry, suggesting that after internalization JEV moves to early and recycling endosomes before the release of the viral genome. Our findings demonstrate the roles of Rab5 and Rab11 on JEV infection of BHK-21 cells through the endocytic pathway, providing new insights into the life cycle of flaviviruses. IMPORTANCE Although Japanese encephalitis virus (JEV) utilizes different endocytic pathways depending on the cell type being infected, the detailed mechanism of its entry into BHK-21 cells is unknown. Understanding the process of JEV endocytosis and postinternalization will advance our knowledge of JEV infection and pathogenesis as well as provide potential novel drug targets for antiviral intervention. With this objective, we used systematic approaches to dissect this process. The results show that entry of JEV into BHK-21 cells requires a low-pH environment and that the process occurs through dynamin-, actin-, and cholesterol-dependent clathrin-mediated endocytosis that requires Rab5 and Rab11. Our work provides a detailed picture of the entry of JEV into BHK-21 cells and the cellular events that follow.

scholarly journals Regulated IRE1-dependent decay pathway is activated during Japanese encephalitis virus-induced unfolded protein response and benefits viral replication

2014 ◽  
Vol 95 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Sankar Bhattacharyya ◽  
Utsav Sen ◽  
Sudhanshu Vrati
Keyword(s):  
Japanese Encephalitis Virus ◽  
Unfolded Protein Response ◽  
Japanese Encephalitis ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Encephalitis Virus ◽  
Host Cells ◽  
Rnase Activity ◽  
Unfolded Protein ◽  
Protein Response

Japanese encephalitis virus (JEV) infection-induced encephalitis causes extensive death or long-term neurological damage, especially among children, in south and south-east Asia. Infection of mammalian cells has shown induction of an unfolded protein response (UPR), presumably leading to programmed cell death or apoptosis of the host cells. UPR, a cellular response to accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen, is initiated by three ER-lumen-resident sensors (PERK, IRE1 and ATF6), and involves transcriptional and translational regulation of the expression of several genes. The sensor IRE1 possesses an intrinsic RNase activity, activated through homo-dimerization and autophosphorylation during UPR. Activated IRE1 performs cytoplasmic cleavage of Xbp1u transcripts, thus facilitating synthesis of XBP1S transcription factor, in addition to cleavage of a cohort of cellular transcripts, the later initiating the regulated IRE1-dependent decay (RIDD) pathway. In this study, we report the initiation of the RIDD pathway in JEV-infected mouse neuroblastoma cells (Neuro2a) and its effect on viral infection. Activation of the RIDD pathway led to degradation of known mouse cell target transcripts without showing any effect on JEV RNA despite the fact that both when biochemically purified showed significant enrichment in ER membrane-enriched fractions. Additionally, inhibition of the IRE1 RNase activity by STF083010, a specific drug, diminished viral protein levels and reduced the titre of the virus produced from infected Neuro2a cells. The results present evidence for the first report of a beneficial effect of RIDD activation on the viral life cycle.

Sign in / Sign up

Export Citation Format

Share Document