Triggering unfolded protein response by 2-Deoxy-d-glucose inhibits porcine epidemic diarrhea virus propagation

Abstract

The unfolded protein response (UPR) is cyto-protective machinery elicited towards an influx of large amount of protein synthesis in the endoplasmic reticulum (ER). Extensive studies suggest that the UPR can also be activated during virus infection. In the present studies, we first evaluated if porcine epidemic diarrhea virus (PEDV) infection activated the UPR pathways. Electron microscopy analysis demonstrated the morphology changes of ER post-PEDV infection. Western blot and real-time PCR identified the differences of UPR genes in response to PEDV infection. The results suggested that PEDV infection induced UPR in Vero cells. Meanwhile, we silenced the expression of PKR-like ER kinase (PERK) by shRNA, we found that the knockdown of PERK increased virus loads in the cells, which was consistent with the result on 4-phenylbutyrate (4-PBA) treatment. We next determined whether 2-Deoxy-d-glucose (2-DG), an ER stress inducer, possessed antiviral activity against PEDV infection. Plaque formation assay, RT-PCR and Western blot analysis suggested that 2-DG might inhibit virus infection by affecting viral protein translation during the early stage of virus infection. Interestingly, we also found that 2-DG treatment could affect virus assembly, which is similar to previous studies on influenza virus. All these results support the therapeutic potential of using 2-DG or glucose/mannose analogs to induce the UPR to block virus replication.

The PERK Arm of the Unfolded Protein Response Negatively Regulates Transmissible Gastroenteritis Virus Replication by Suppressing Protein Translation and Promoting Type I Interferon Production

“…5A to I), indicating that IRE1 activation facilitates viral replication. The UPR PERK branch is highly associated with viral replication and pathogenesis (8,21,22,61). Here, we demonstrated that the TGEV-induced UPR PERK activation primarily accounted for the increased eIF2␣ phosphorylation and negatively regulated TGEV replication.…”

“…Here, we demonstrated that the TGEV-induced UPR PERK activation primarily accounted for the increased eIF2␣ phosphorylation and negatively regulated TGEV replication. Induction of the UPR PERK has also been reported to suppress another alphacoronavirus, porcine epidemic diarrhea virus (PEDV) (61). This finding is different from the results in IBV, whose replication is not significantly affected by the suppression of eIF2␣ dephosphorylation by salubrinal (18,20).…”

Glycyrrhizin inhibits porcine epidemic diarrhea virus infection and attenuates the proinflammatory responses by inhibition of high mobility group box-1 protein

“…PEDV was adapted for eight passages in Vero cells. PEDV was inactivated by UV light exposure [42]. The loss of infectivity of UV-inactivated virus was confirmed using the plaque formation assay.…”

Virulence factors in porcine coronaviruses and vaccine design

“…The infection with many CoVs induces ER stress, and a role of UPR in pathogenesis has been described (DeDiego et al, 2011). In the case of enteric porcine CoVs, the induction of the UPR response has been reported for PEDV, with a negative effect on viral replication (Wang et al, 2014b). In contrast, TGEV infection does not induce ER stress (Cruz et al, 2011), despite the increased expression of several UPR mediators such as ATF4 or GADD34 after infection [(Cruz et al, 2011), S. Zuñiga and L. Enjuanes, unpublished results].…”