title: Cell entry of bovine ephemeral fever virus requires activation of Src-JNK-AP1 and PI3K-Akt-NF-κB pathways as well as Cox-2-mediated PGE2 /EP receptor signalling to enhance clathrin-mediated virus endocytosis.
abstract: Although we have previously demonstrated that cell entry of bovine ephemeral fever virus (BEFV) follows a clathrin-mediated and dynamin 2-dependent endocytosis pathway, the cellular mechanism mediating virus entry remains unknown. Here, we report that BEFV triggers simultaneously Src-JNK-AP1 and PI3K-Akt-NF-κB signalling pathways in the stage of virus binding to induce clathrin and dynamin 2 expressions, while vesicular stomatitis virus only activates Src-JNK signalling to enhance its entry. Activation of these pathways by ultraviolet-inactivated BEFV suggests a role for virus binding but not viral internalization and gene expression. By blocking these signalling pathways with specific inhibitors, BEFV-induced expressions of clathrin and dynamin 2 were significantly diminished. By labelling BEFV with 3,3'-dilinoleyloxacarbocyanine perchlorate to track viral entry, we found that virus entry was hindered by both Src and Akt inhibitors, suggesting that these signalling pathways are crucial for efficient virus entry. In addition, BEFV also triggers Cox-2-catalysed prostaglandin E2 (PGE2) synthesis and induces expressions of G-protein-coupled E-prostanoid (EP) receptors 2 and 4, leading to amplify signal cascades of Src-JNK-AP1 and PI3K-Akt-NF-κB, which elevates both clathrin and dynamin 2 expressions. Furthermore, pretreatment of cells with adenylate cyclase (cAMP) inhibitor SQ22536 reduced BEFV-induced Src phosphorylation as well as clathrin and dynamin 2 expressions. Our findings reveal for the first time that BEFV activates the Cox-2-mediated PGE2/EP receptor signalling pathways, further enhancing Src-JNK-AP1 in a cAMP-dependent manner and PI3K-Akt-NF-κB in a cAMP-independent manner. Accordingly, BEFV stimulates PGE2/EP receptor signalling amplifying Src-JNK-AP1 and PI3K-Akt-NF-κB pathways in an autocrine or paracrine fashion to enhance virus entry.
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Ching-Yuan
authors.initials: CY
authors.lastname: Cheng
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Wei-Ru
authors.initials: WR
authors.lastname: Huang
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Pei-I
authors.initials: PI
authors.lastname: Chi
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Hung-Chuan
authors.initials: HC
authors.lastname: Chiu
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, 402, Taiwan.|Agricultural Biotechnology Center, National Chung Hsing University, Taichung, 402, Taiwan.|Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Hung-Jen
authors.initials: HJ
authors.lastname: Liu
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D004705:Endocytosis; D018115:Ephemeral Fever Virus, Bovine / Q000502:physiology*; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D058307:Receptors, Prostaglandin E, EP2 Subtype / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D053586:Virus Internalization
chemical_list: D002966:Clathrin; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D015232:Dinoprostone