Gene Expression Profiling of Endoplasmic Reticulum Stress in Hepatitis C Virus-Containing Cells Treated with an Inhibitor of Protein Disulfide Isomerases

Abstract

Protein disulfide isomerases (PDIs) catalyze disulfide bond formation between protein cysteine residues during protein folding in the endoplasmic reticulum (ER) lumen and are essential for maintaining ER homoeostasis. The life cycle of the hepatitis C virus (HCV) is closely associated with the ER. Synthesis and maturation of HCV proteins occur in the ER membrane and are mediated by multiple host cell factors that include also PDI. Here, we present a study investigating the effect of PDI inhibition on Huh7 human hepatoma cells harboring an HCV subgenomic replicon using the abscisic acid-derived PDI inhibitor origamicin. Transcriptional profiling shows that origamicin changed the expression levels of genes involved in the oxidative and ER stress responses and the unfolded protein response, as indicated by the upregulation of antioxidant enzymes and chaperone proteins, the downregulation of cell-cycle proteins, and induction of apoptosis-associated genes. Our data suggest that origamicin negatively impacts HCV replication by causing an imbalance in cellular homoeostasis and induction of stress responses. These insights suggest that inhibition of PDIs by low-molecular-weight inhibitors could be a promising approach to the discovery of novel antiviral compounds.

Intracellular Redox-Modulated Pathways as Targets for Effective Approaches in the Treatment of Viral Infection

“…The essential role of PDI for the efficient oxidative folding of HA has been corroborated by the finding that treatment with PDI inhibitor decreases intramolecular disulfide bond formation and the subsequent maturation of IAV in infected lung epithelial cells, resulting in diminished viral load and proinflammatory responses [ 93 ]. A role of PDI in the life cycle of HCV and potentially of other members of the Flaviviridae family has been also described [ 94 , 95 ].…”

Endoplasmic Reticulum Chaperones in Viral Infection: Therapeutic Perspectives

“…This effect was observed in the early stages of infection. Another small molecule derived from abscisic acid, origamicin, was shown to inhibit HCV replication ( 222 ). Using a microarray mRNA profiling, the authors propose that besides the inhibition of disulfide bond formation in E1 and E2 glycoproteins, this molecule perturbates ER homeostasis through PDI inhibition, thus disrupting the portion of the HCV viral cycle which occurs in the ER.…”

The Impact of Endoplasmic Reticulum-Associated Protein Modifications, Folding and Degradation on Lung Structure and Function

“…During replication, HA interacts with ER chaperones like CNX and CRT for proper folding ( Hebert et al, 1997 ). Additionally, PDIs are essential for the efficient oxidative folding of viral proteins, including PDIA3 on HA of IAV, PDIA1 on the E1 and E2 glycoproteins of hepatitis C virus, and PDIA3 on the F proteins of respiratory syncytial and Sendai viruses ( Solda et al, 2006 ; Kim and Chang, 2018 ; Ozcelik et al, 2018 ; Piacentini et al, 2018 ). PDIA3 forms S–Ss between cysteine residues in HA and is significantly upregulated in mouse lungs following infection by various strains of IAV, as well as in human lung epithelial cells following infection with a pandemic, although not a seasonal strain of influenza ( Chamberlain et al, 2019 ).…”