Functional microRNA screen uncovers O-linked N-acetylglucosamine transferase as a host factor modulating hepatitis C virus morphogenesis and infectivity

Abstract

ObjectiveInfection of human hepatocytes by the hepatitis C virus (HCV) is a multistep process involving both viral and host factors. microRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. Given that miRNAs were indicated to regulate between 30% and 75% of all human genes, we aimed to investigate the functional and regulatory role of miRNAs for the HCV life cycle.DesignTo systematically reveal human miRNAs affecting the HCV life cycle, we performed a two-step functional high-throughput miRNA mimic screen in Huh7.5.1 cells infected with recombinant cell culture-derived HCV. miRNA targeting was then assessed using a combination of computational and functional approaches.ResultsWe uncovered miR-501-3p and miR-619-3p as novel modulators of HCV assembly/release. We discovered that these miRNAs regulate O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) protein expression and identified OGT and O-GlcNAcylation as regulators of HCV morphogenesis and infectivity. Furthermore, increased OGT expression in patient-derived liver tissue was associated with HCV-induced liver disease and cancer.ConclusionmiR-501-3p and miR-619-3p and their target OGT are previously undiscovered regulatory host factors for HCV assembly and infectivity. In addition to its effect on HCV morphogenesis, OGT may play a role in HCV-induced liver disease and hepatocarcinogenesis.

O-GlcNAcylation of SAMHD1 Indicating a Link between Metabolic Reprogramming and Anti-HBV Immunity

“…Although we could not exclude the possibility that differences between HBV cell models cause this discrepancy, our results show that increased HBP flux and hyper-O-GlcNAcylation can upregulate host antiviral innate response. Several other studies have reported that HBP and/or protein O-GlcNAcylation promotes host antiviral immunity against RNA viruses, including VSV (Li et al , 2018), influenza virus (Song et al , 2019), and hepatitis C virus (Herzog et al , 2019). Thus, the present study confirms and expands our current understanding of the antiviral activity of HBP and protein O-GlcNAcylation upon DNA virus infection, which is similar to its antiviral activity upon infection by certain RNA viruses.…”

“…Herzog et al . demonstrated that protein O-GlcNAcylation is involved in HCV-induced disease progression and carcinogenesis (Herzog et al , 2019). Thus, the role of protein O-GlcNAcylation in HBV pathogenesis and the antiviral response through enhanced protein O-GlcNAcylation remain to be further studied.…”

The role of O‐GlcNAcylation in immunity against infections

“…For example, studies with hepatitis C virus revealed an increased size of virions and increased ability to infect liver cells following OGT knockdown in these host cells. 73 These studies indicate an effect of O-GlcNAcylation on pathogen virulence and morphology. Moreover, human T-cell lymphotropic virus type 1 (HTLV-1) requires O-GlcNAcylation of the host transcription factor cAMP-response element-binding protein for transcription from its long terminal repeat.…”

Common and Strain-Specific Post-Translational Modifications of the Potyvirus Plum pox virus Coat Protein in Different Hosts

“…The CP of another potyvirus, Plum pox virus (PPV), is also phosphorylated [28,29]. Interestingly, PPV CP is also modified by a second PTM, O-GlcNAcylation [28,30], which is known to be functionally linked to phosphorylation in many dynamic regulatory activities [31] and has been shown to play important roles in animal virus infections [32][33][34][35]. This makes PPV CP an attractive subject to study the joint contribution of these closely related PTMs in the regulation of viral infection.…”