Persistent prion infection disturbs the function of Oct-1, resulting in the down-regulation of murine interferon regulatory factor-3

Abstract

As a prompt response against invasion of various viruses, interferon regulatory factor-3 (IRF-3) is initially phosphorylated to become activated and upregulates mainly Type I Interferons (IFN-I) in most cell types. We previously reported that IRF-3-dependent host innate immune responses partially interfere in infection of prions. Here, we found that stable infection of prion suppressed IRF-3 gene-expression. The decreased promoter activity of IRF-3 was significantly restored along with treatment of anti-prion drugs in the prion-infected cells, suggesting that infection of prion directly influence the regulation of IRF-3 transcription. We further investigated promoter activity of 5′- flanking region of murine IRF-3 using a luciferase reporter system and found that the nucleotides -119 to -1 were indispensable for the promoter activity. Within this region, mutations in the Oct-1 binding site significantly reduced the promoter activity and chromatin immunoprecipitation (ChIP) assay revealed that Oct-1 indeed binds to the region. In addition, overexpression of Oct-1 increased the promoter activity of IRF-3. Intriguingly, Oct-1 protein was significantly reduced in prion-infected cells and mice brains compared with uninfected groups. Taken together, we concluded that prion infection could interfere in the function of Oct-1, resulting in the down-regulation of IRF-3.

Structure-Based Drug Discovery for Prion Disease Using a Novel Binding Simulation

“…N2a-FK cells established from N2a-58 cells were infected with a mouse-adapted Gerstmann–Sträussler–Scheinker strain, Fukuoka-1, as previously described ( Ishibashi et al, 2015 , Ishibashi et al, 2011 ). N2a-22L cells were established from N2a-58 cells infected with a mouse-adapted scrapie 22L strain as previously described ( Homma et al, 2015 , Homma et al, 2014a , Nishida et al, 2000 ). The above cells were grown at 37 °C in 5% CO 2 in Dulbecco's-modified Eagle's medium (Wako) containing 4500 mg/mL glucose, 10% heat-inactivated fetal bovine serum, 100 units/mL penicillin and 100 μg/mL streptomycin (Nakarai Tesque).…”

Ubiquitin-specific protease 14 modulates degradation of cellular prion protein

“…N2a58 cells are mouse PrP C -overexpressing Neuro 2a cells. ScN2a58 cells originated from N2a58 cells infected with a mouse-adapted scrapie strain, 22 L, as previously described 36 37 38 . FK-N2a58 cells originated from N2a58 cells infected with a mouse-adapted Gerstmann-Sträussler-Scheinker (GSS) strain, Fukuoka-1, as previously described 39 .…”

Type I interferon protects neurons from prions inin vivomodels

“…After 20 h, the cells were lysed using Passive Lysis Buffer (Promega) and the luciferase activity was detected by the Dual Reporter Assay System (Promega) and quantified using the Mithras LB940 luminometer instrument (Berthold Technologies). Data of luciferase activity were normalized by value of the co-expressed Renilla activity as previously described (Homma et al , 2014 a ).…”

“…However, accumulated evidence has shown that prion infection stimulates pattern recognition receptor (PRR)-related molecules and related signalling pathways, including Toll-like receptors (TLRs), interferon regulatory factors (IRFs), and some cytokines (Prinz et al , 2003; Spinner et al , 2008; Bradford and Mabbott, 2012; Ishibashi et al , 2012 a ; Nuvolone et al , 2015; Kang et al , 2016). We have also reported that IRF3, which upregulates type I interferon (I-IFN) in various cell types, including neurons, plays a role in host defence against prion infection (Ishibashi et al , 2012 a , b ), and that persistent prion infection negatively regulates IRF3 via suppression of the transcription factor Octamer-binding protein-1 (Oct-1) (Homma et al , 2014 a ). Prions also exhibit strain diversity and reciprocal interference between strains, analogous to viral infections (Dickinson et al , 1972, 1975; Manuelidis, 1998).…”