Dataset Information

Japanese encephalitis virus infects porcine kidney epithelial PK15 cells via clathrin- and cholesterol-dependent endocytosis.

ABSTRACT: BACKGROUND: Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes acute viral encephalitis in humans. Pigs are important amplifiers of JEV. The entry mechanism of JEV into porcine cells remains largely unknown. In this study, we present a study of the internalization mechanism of JEV in porcine kidney epithelial PK15 cells. RESULTS: We demonstrated that the disruption of the lipid raft by cholesterol depletion with methyl-?-cyclodextrin (M?CD) reduced JEV infection. We also found that the knockdown of clathrin by small interfering RNA (siRNA) significantly reduced JEV-infected cells and JEV E-glycoprotein levels, suggesting that JEV utilizes clathrin-dependent endocytosis. In contrast, the knockdown of caveolin-1, a principal component of caveolae, had only a small (although statistically significant) effect on JEV infection, however, JEV entry was not affected by genistein. These results suggested that JEV entry was independent of caveolae. CONCLUSIONS: Taken together, our results demonstrate that JEV enters porcine kidney epithelial PK15 cells through cholesterol- and clathrin-mediated endocytosis.

SUBMITTER: Yang S

PROVIDER: S-EPMC3751042 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Japanese encephalitis virus infects porcine kidney epithelial PK15 cells via clathrin- and cholesterol-dependent endocytosis.

Yang Songbai S He Minhui M Liu Xiangdong X Li Xinyun X Fan Bin B Zhao Shuhong S

Virology journal 20130812

<h4>Background</h4>Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes acute viral encephalitis in humans. Pigs are important amplifiers of JEV. The entry mechanism of JEV into porcine cells remains largely unknown. In this study, we present a study of the internalization mechanism of JEV in porcine kidney epithelial PK15 cells.<h4>Results</h4>We demonstrated that the disruption of the lipid raft by cholesterol depletion with methyl-β-cyclodextrin (MβCD) reduced JEV infe ...[more]

PMID: 23937769

Similar Datasets

Project description: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.

Project description:Porcine deltacoronavirus (PDCoV), an emerging enteropathogenic coronavirus, causes serious diarrhea in suckling piglets and has the potential for cross-species transmission. Although extensive studies have been reported on the biology and pathogenesis of PDCoV, the mechanisms by which PDCoV enters cells are not well characterized. In this study, we investigated how PDCoV enters IPI-2I cells, a line of porcine intestinal epithelial cells derived from pig ileum. Immunofluorescence assays, small interfering RNA (siRNA) interference, specific pharmacological inhibitors, and dominant negative mutation results revealed that PDCoV entry into IPI-2I cells depended on clathrin, dynamin, and a low-pH environment but was independent of caveolae. Specific inhibition of phosphatidylinositol 3-kinase (PI3K) and the Na+/H+ exchanger (NHE) revealed that PDCoV entry involves macropinocytosis and depends on NHE rather than on PI3K. Additionally, Rab5 and Rab7, but not Rab11, regulated PDCoV endocytosis. This is the first study to demonstrate that PDCoV uses clathrin-mediated endocytosis and macropinocytosis as alternative endocytic pathways to enter porcine intestinal epithelial cells. We also discussed the entry pathways of PDCoV into other porcine cell lines. Our findings reveal the entry mechanisms of PDCoV and provide new insight into the PDCoV life cycle. IMPORTANCE An emerging enteropathogenic coronavirus, PDCoV, has the potential for cross-species transmission, attracting extensive attenuation. Characterizing the detailed process of PDCoV entry into cells will deepen our understanding of the viral infection and pathogenesis and provide clues for therapeutic intervention against PDCoV. With the objective, we used complementary approaches to dissect the process in PDCoV-infected IPI-2I cells, a line of more physiologically relevant intestinal epithelial cells to PDCoV infection in vivo. Here, we demonstrate that PDCoV enters IPI-2I cells via macropinocytosis, which does not require a specific receptor, and clathrin-mediated endocytosis, which requires a low-pH environment and dynamin, while a caveola-mediated endocytic pathway is used by PDCoV to enter swine testicular (ST) cells and porcine kidney (LLC-PK1) cells. These findings provide a molecular detail of the cellular entry pathways of PDCoV and may direct us toward novel antiviral drug development.

Project description:Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurovirulent coronavirus that invades the central nervous system (CNS) in piglets. Although important progress has been made toward understanding the biology of PHEV, many aspects of its life cycle remain obscure. Here we dissected the molecular mechanism underlying cellular entry and intracellular trafficking of PHEV in mouse neuroblastoma (Neuro-2a) cells. We first performed a thin-section transmission electron microscopy (TEM) assay to characterize the kinetics of PHEV, and we found that viral entry and transfer occur via membranous coating-mediated endo- and exocytosis. To verify the roles of distinct endocytic pathways, systematic approaches were used, including pharmacological inhibition, RNA interference, confocal microscopy analysis, use of fluorescently labeled virus particles, and overexpression of a dominant negative (DN) mutant. Quantification of infected cells showed that PHEV enters cells by clathrin-mediated endocytosis (CME) and that low pH, dynamin, cholesterol, and Eps15 are indispensably involved in this process. Intriguingly, PHEV invasion leads to rapid actin rearrangement, suggesting that the intactness and dynamics of the actin cytoskeleton are positively correlated with viral endocytosis. We next investigated the trafficking of internalized PHEV and found that Rab5- and Rab7-dependent pathways are required for the initiation of a productive infection. Furthermore, a GTPase activation assay suggested that endogenous Rab5 is activated by PHEV and is crucial for viral progression. Our findings demonstrate that PHEV hijacks the CME and endosomal system of the host to enter and traffic within neural cells, providing new insights into PHEV pathogenesis and guidance for antiviral drug design.IMPORTANCE Porcine hemagglutinating encephalomyelitis virus (PHEV), a nonsegmented, positive-sense, single-stranded RNA coronavirus, invades the central nervous system (CNS) and causes neurological dysfunction. Neural cells are its targets for viral progression. However, the detailed mechanism underlying PHEV entry and trafficking remains unknown. PHEV is the etiological agent of porcine hemagglutinating encephalomyelitis, which is an acute and highly contagious disease that causes numerous deaths in suckling piglets and enormous economic losses in China. Understanding the viral entry pathway will not only advance our knowledge of PHEV infection and pathogenesis but also open new approaches to the development of novel therapeutic strategies. Therefore, we employed systematic approaches to dissect the internalization and intracellular trafficking mechanism of PHEV in Neuro-2a cells. This is the first report to describe the process of PHEV entry into nerve cells via clathrin-mediated endocytosis in a dynamin-, cholesterol-, and pH-dependent manner that requires Rab5 and Rab7.

Dataset Information

Japanese encephalitis virus infects porcine kidney epithelial PK15 cells via clathrin- and cholesterol-dependent endocytosis.

Publications

Japanese encephalitis virus infects porcine kidney epithelial PK15 cells via clathrin- and cholesterol-dependent endocytosis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets