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 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 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 Dual interaction of the malaria circumsporozoite protein with the low density lipoprotein receptor-related protein (LRP) and heparan sulfate proteoglycans.

1996 ◽  
Vol 184 (5) ◽  
pp. 1699-1711 ◽  
Author(s):  
M Shakibaei ◽  
U Frevert
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Heparan Sulfate Proteoglycans ◽  
Low Density ◽  
Lipoprotein Receptor ◽  
Related Protein ◽  
Density Lipoprotein Receptor ◽  
Lipoprotein Receptor Related Protein

Speed and selectivity of hepatocyte invasion by malaria sporozoites have suggested a receptor-mediated mechanism and the specific interaction of the circumsporozoite (CS) protein with liver-specific heparan sulfate proteoglycans (HSPGs) has been implicated in the targeting to the liver. Here we show that the CS protein interacts not only with cell surface heparan sulfate, but also with the low density lipoprotein receptor-related protein (LRP). Binding of 125I-CS protein to purified LRP occurs with a Kd of 4.9 nM and can be inhibited by the receptor-associated protein (RAP). Blockage of LRP by RAP or anti-LRP antibodies on heparan sulfate-deficient CHO cells results in more than 90% inhibition of binding and endocytosis of recombinant CS protein. Conversely, blockage or enzymatic removal of the cell surface heparan sulfate from LRP-deficient embryonic mouse fibroblasts yields the same degree of inhibition. Heparinase-pretreatment of LRP-deficient fibroblasts or blockage of LRP on heparan sulfate-deficient CHO cells by RAP, lactoferrin, or anti-LRP antibodies reduces Plasmodium berghei invasion by 60-70%. Parasite development in heparinase-pretreated HepG2 cells is inhibited by 65% when RAP is present during sporozoite invasion. These findings suggest that malaria sporozoites utilize the interaction of the CS protein with HSPGs and LRP as the major mechanism for host cell invasion.

scholarly journals Low density lipoprotein receptor–related protein is a calreticulin coreceptor that signals focal adhesion disassembly

2003 ◽  
Vol 161 (6) ◽  
pp. 1179-1189 ◽  
Author(s):  
Anthony Wayne Orr ◽  
Claudio E. Pedraza ◽  
Manuel Antonio Pallero ◽  
Carrie A. Elzie ◽  
Silvia Goicoechea ◽  
...  
Keyword(s):  
Cell Surface ◽  
Focal Adhesion ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein Receptor ◽  
Related Protein ◽  
Low Density Lipoprotein Receptor ◽  
Density Lipoprotein Receptor ◽  
Lipoprotein Receptor Related Protein

Thrombospondin (TSP) signals focal adhesion disassembly (the intermediate adhesive state) through interactions with cell surface calreticulin (CRT). TSP or a peptide (hep I) of the active site induces focal adhesion disassembly through binding to CRT, which activates phosphoinositide 3-kinase (PI3K) and extracellular signal–related kinase (ERK) through Gαi2 proteins. Because CRT is not a transmembrane protein, it is likely that CRT signals as part of a coreceptor complex. We now show that low density lipoprotein receptor–related protein (LRP) mediates focal adhesion disassembly initiated by TSP binding to CRT. LRP antagonists (antibodies, receptor-associated protein) block hep I/TSP-induced focal adhesion disassembly. LRP is necessary for TSP/hep I signaling because TSP/hep I is unable to stimulate focal adhesion disassembly or ERK or PI3K signaling in fibroblasts deficient in LRP. LRP is important in TSP–CRT signaling, as shown by the ability of hep I to stimulate association of Gαi2 with LRP. The isolated proteins LRP and CRT interact, and LRP and CRT are associated with hep I in molecular complexes extracted from cells. These data establish a mechanism of cell surface CRT signaling through its coreceptor, LRP, and suggest a novel function for LRP in regulating cell adhesion.

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 Mutation analysis of the cross-reactive epitopes of Japanese encephalitis virus envelope glycoprotein

2012 ◽  
Vol 93 (6) ◽  
pp. 1185-1192 ◽  
Author(s):  
Shyan-Song Chiou ◽  
Yi-Chin Fan ◽  
Wayne D. Crill ◽  
Ruey-Yi Chang ◽  
Gwong-Jen J. Chang
Keyword(s):  
Amino Acid ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Recombinant Expression ◽  
Encephalitis Virus ◽  
Site Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Virus Envelope ◽  
E Protein ◽  
Domain Iii

Group and serocomplex cross-reactive epitopes have been identified in the envelope (E) protein of several flaviviruses and have proven critical in vaccine and diagnostic antigen development. Here, we performed site-directed mutagenesis across the E gene of a recombinant expression plasmid that encodes the Japanese encephalitis virus (JEV) premembrane (prM) and E proteins and produces JEV virus-like particles (VLPs). Mutations were introduced at I135 and E138 in domain I; W101, G104, G106 and L107 in domain II; and T305, E306, K312, A315, S329, S331, G332 and D389 in domain III. None of the mutant JEV VLPs demonstrated reduced activity to the five JEV type-specific mAbs tested. Substitutions at W101, especially W101G, reduced reactivity dramatically with all of the flavivirus group cross-reactive mAbs. The group and JEV serocomplex cross-reactive mAbs examined recognized five and six different overlapping epitopes, respectively. Among five group cross-reactive epitopes, amino acids located in domains I, II and III were involved in one, five and three epitopes, respectively. Recognition by six JEV serocomplex cross-reactive mAbs was reduced by amino acid substitutions in domains II and III. These results suggest that amino acid residues located in the fusion loop of E domain II are the most critical for recognition by group cross-reactive mAbs, followed by residues of domains III and I. The amino acid residues of both domains II and III of the E protein were shown to be important in the binding of JEV serocomplex cross-reactive mAbs.

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