The Sp1-Responsive microRNA-15b Negatively Regulates Rhabdovirus-Triggered Innate Immune Responses in Lower Vertebrates by Targeting TBK1

Abstract

As is known to all, the production of type I interferon (IFN) plays pivotal roles in host innate antiviral immunity, and its moderate production play a positive role in promoting the activation of host innate antiviral immune response. However, the virus will establish a persistent infection model by interfering with the production of IFN, thereby evading the organism inherent antiviral immune response. Therefore, it is of great necessity to research the underlying regulatory mechanisms of type I IFN appropriate production under viral invasion. In this study, we report that a Sp1–responsive miR-15b plays a negative role in siniperca chuatsi rhabdovirus (SCRV)-triggered antiviral response in teleost fish. We found that SCRV could dramatically upregulate miiuy croaker miR-15b expression. Enhanced miR-15b could negatively regulate SCRV-triggered antiviral genes and inflammatory cytokines production by targeting TANK-binding kinase 1 (TBK1), thereby accelerating viral replication. Importantly, we found that miR-15b feedback regulates antiviral innate immune response through NF-κB and IRF3 signaling pathways. These findings highlight that miR-15b plays a crucial role in regulating virus–host interactions, which outlines a new regulation mechanism of fish’s innate immune responses.

Regulation of CIRP by genetic factors of SP1 related to cold sensitivity

“…SP1 is a well-known transcription factor involved in various biological processes. Recently, several studies have reported a role for SP1 in the immune system (42)(43)(44)(45)(46). SP1 is also known to be involved in inflammation, which is an element of the immune system (29, [47][48][49][50][51].…”

microRNA-210 and microRNA-3570 Negatively Regulate NF-κB-Mediated Inflammatory Responses by Targeting RIPK2 in Teleost Fish

“…Therefore, in our study, to avoid nonspecific effects of excessive accumulation of this high molecular weight RNA species on target gene expression, we prolonged the transfection time with miRNA mimics and to study the effect of miRNA on target genes. In teleost fish, many researches have shown that endogenous regulatory molecules miRNAs can regulate the immune response by regulating crucial immune-related genes, such as MITA, IRAK4, TBK1 (54)(55)(56). However, there are few reports on the regulation of RIPK2 by miRNAs.…”

Long Noncoding RNA MIR122HG Inhibits MAVS-Mediated Antiviral Immune Response by Deriving miR-122 in Miiuy Croaker (Miichthys miiuy)

“…The expression analysis of miR-122 was executed by using the miRcute miRNA qPCR Detection Kit (Tiangen, Beijing, China). Real-time quantitative PCR (qPCR) was performed in an Applied Biosystems QuantStudio 3 (Thermo Fisher Scientific, Waltham, MA, USA), as we described previously [ 49 ]. The primers for these genes and miRNAs are shown in Supplementary Table S1 .…”

“…For miRNA target identification, EPC cells and HEK293 cells were cotransfected with wild- or mutant-type MAVS 3′-UTR luciferase reporter, together with MIR122HG or pcDNA3.1. Moreover, to determine the functional regulation of MAVS, EPC cells were cotransfected with NF-κB, Interferon regulatory factor 3 (IRF3), IFN-stimulated response element (ISRE) or type I interferon (IFN-1) luciferase reporter plasmid [ 25 , 49 ], pRL-TK Renilla luciferase plasmid, and MAVS expression plasmid, together with either MIR122HG, MIR122HG-MT or pcDNA3.1, miR-122 mimics or NC, and inhibitors or inhibitor control for dual-luciferase reporter assay. Then, the cells were collected and lysed for reporter activity assays using a dual-luciferase reporter assay system (Promega Madison, WI, USA), according to the manufacturer’s instructions.…”