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

SummaryAlthough 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 E 2 (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 PGE 2/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.

Identification and phylogenetic characterization of bovine ephemeral fever virus (BEFV) of Middle Eastern lineage associated with 2018‐2019 outbreaks in India

“…Likewise, glycoprotein (G), the prominent surface protein projecting on the surface of the virion, significantly responsible for the attachment of the virus to host cell receptors, thus is the dominant target of virus-neutralizing antibodies (Coll, 1995;Cybinski, Walker, Byrne, & Zakrzewski, 1990;Uren, Walker, Zakrzewski, St George, & Byrne, 1994). In doing so, it activates the SrcJNKAP1 and PI3KAktNFκB signalling (Cheng, Huang, Chi, Chiu, & Liu, 2015) leading to the upregulation of clathrin-mediated and dynamin 2-dependent endocytosis pathways, thereby enhancing virus entry and infectivity (Cheng et al, 2012). Therefore, our study targeted the above-mentioned genes as they may provide an evident idea on BEFV identification followed by detection of the prevalent strain type that existed and currently circulating in the Indian subcontinent.…”

The Src kinases Hck, Fgr, and Lyn activate Abl2/Arg to facilitate IgG-mediated phagocytosis andLeishmaniainfection

“…Src and Lyn directly bind the FcR , and macrophages lacking the SFKs Hck, Lyn and Fgr have substantial defects in IgG-mediated phagocytosis (Fitzer-Attas et al, 2000), and viral (Abram and Lowell, 2008;Bavagnoli et al, 2011;Cheng et al, 2015) and bacterial uptake (Hauck et al, 1998;Paul et al, 2008;Van Langendonck et al, 1998). SFKs phosphorylate and activate Arg (Mader et al, 2011;Plattner et al, 2004;Tanis et al, 2003), and this can be amplified by Arg autophosphorylation on a distinct regulatory site (Bradley and Koleske, 2009).…”

Infectious Bursal Disease Virus Activates c-Src To Promote α4β1 Integrin-Dependent Viral Entry by Modulating the Downstream Akt-RhoA GTPase-Actin Rearrangement Cascade

“…c-Src has been implicated in the regulation of the life cycles of various viruses. A number of viruses, including herpes simplex virus 8 (human herpesvirus 8 [HHV8]) (23), Japanese encephalitis virus (JEV) (a member of the genus Flavivirus of the family Flaviviridae) (24), and bovine ephemeral fever virus (BEFV) (a member of the genus Ephemerovirus of the family Rhabdoviridae) (25), stimulate c-Src phosphorylation to facilitate virus entry. One of the possible mechanisms is that c-Src bridges between the upstream surface ␣4␤1 integrin receptors and downstream phosphatidylinositol-3-kinase (PI3K)/Akt signaling cascades.…”