Comparative Transcriptomic and Proteomic Analyses Prove that IFN-λ1 is a More Potent Inducer of ISGs than IFN-α against Porcine Epidemic Diarrhea Virus in Porcine Intestinal Epithelial Cells

Abstract

Type III interferon (IFN-λ) is currently considered to be largely nonredundant to type I interferon (IFN-α) in antivirus infection, especially in epithelial cells. Previous studies reported that, compared with IFN-α, IFN-λ exhibited stronger induction of interferon-stimulated genes (ISGs) at the transcriptional level in intestinal epithelial cells and stronger inhibition of porcine epidemic diarrhea virus (PEDV). In this study, the different mechanisms of ISG upregulation induced by IFN-α and IFN-λ1 were compared at the mRNA and protein levels in the porcine intestinal epithelial cell model (IPEC-J2). It was proved that IFN-λ1 consistently exhibited stronger stimulation effects at both levels. At the mRNA level, 132 genes were significantly upregulated upon IFN-λ1 stimulation, while 42 genes upon IFN-α stimulation. At the protein level, 47 proteins were significantly upregulated upon IFN-λ1 stimulation, but only 8 proteins were upregulated upon IFN-α stimulation. The shared upregulated genes/proteins by IFN-λ1 in both transcriptional and translational omics, especially the regulation factors of ISG15, were involved in the JAK−STAT signaling pathway. Compared to IFN-α, IFN-λ1 could induce more consistent upregulation of the key ISGs (ISG15, USP18, OASL, and RSAD2) at 3−24 h postinduction as measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) validation. It was further confirmed through functional analysis that ISG15 and RSAD2 could inhibit PEDV infection in dose-dependent manners. This study provided solid evidence that IFN-λ1 could induce a more unique and higher ISG expression level, which exhibited anti-PEDV effects on porcine intestinal epithelial cells.

Pseudorabies virus-induced expression and antiviral activity of type I or type III interferon depend on the type of infected epithelial cell

“…In line with this, in IPEC-J2 cells, IFN-λ3 triggered a much more robust expression of ISGs compared to IFN-α and protein levels of the type III IFN receptor chain IFNLR1 were high in IPEC-J2 whereas those of the type I IFN receptor chain IFNAR2 were low. Further in line with these results, using the same IPEC-J2 cells, type III IFN triggered a stronger anti-PEDV effect than type I IFNs, which also correlated with similar differences in ISG expression ( 21 , 38 , 51 ). Exogenous addition of either type of IFN efficiently inhibited SARS-CoV-2 replication and reduced release of infectious virus particles in T84 and Caco-2 human intestinal cell lines.…”

Generation and functional analysis of single chain variable fragments (scFvs) targeting the nucleocapsid protein of Porcine epidemic diarrhea virus

“…Because PEDV mainly infects porcine small-intestinal epithelial cells and causes severe mucosal atrophy and congestion, the expression of type III IFN, which plays an important role in the mucosal antiviral defenses, should be considered in this context. IFN-λ1 and IFN-λ3 exert more powerful antiviral activity than IFN-α against PEDV in IPEC-J2 cells (Li et al 2017 , 2019 ; Zhao et al 2020 ). To evade the antiviral effects of IFNs, viruses have evolved various sophisticated mechanisms to regulate IFN expression.…”

“…The IFNs are divided into three different types, type I (IFN-α and IFN-β), type II (IFN-γ), and type III (IFN-λ). Recent studies have shown that the type I and type III IFNs were central to the host’s resistance to viral infection (Mesev et al 2019 ) and that IFN-λ1 was more effective against PEDV infection of IPEC-J2 cells than IFN-α (Zhao et al 2020 ).…”

Porcine epidemic diarrhea virus strain FJzz1 infection induces type I/III IFNs production through RLRs and TLRs-mediated signaling

“…In the present study, we found that the mRNA expressions of ISGs including RASD2, OAS1, Mx1, Mx2, IFIT1, and ISG15 in FJzz1-infected LLC-PK1 cells were upregulated significantly in dose-dependent manners, indicating that the innate immune responses mediated by ISGs were induced and activated by FJzz1 infection. Remarkably, RSAD2 and ISG15 were confirmed to inhibit CV777 replication in Vero E6 cells through functional analysis ( 64 ). Therefore, we speculated that the abundant ISGs induced by PEDV infection might display excellent antiviral activities.…”