Transcriptional Regulation of gga-miR-451 by AhR:Arnt in Mycoplasma gallisepticum (HS Strain) Infection

Xiuli Peng,Yali Fu,Mengyun Zou,Yabo Zhao,Yingfei Sun

doi:10.3390/ijms20123087

Abstract

MicroRNAs (miRNAs) have been determined to be important regulators for pathogenic microorganism infection. However, it is largely unclear how miRNAs are triggered during pathogen infection. We previously reported that the up-regulation of gga-miR-451 negatively regulates the Mycoplasma gallisepticum (MG)-induced production of inflammatory cytokines via targeting tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ). The aim of this study was to investigate the mechanism regulating gga-miR-451 in MG infection in chickens. Analysis of gga-miR-451 precursor, pri-miR-451, and pre-miR-451 indicated that the regulation occurred transcriptionally. We also identified the transcriptional regulatory region of gga-miR-451 that contained consensus-binding motif for aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (Arnt) complex, which is known as the transcription factor that regulates gene expression. Luciferase reporter assays combined with chromatin immunoprecipitation (ChIP) demonstrated that AhR:Arnt bound directly to the promoter elements of gga-miR-451, which were responsible for gga-miR-451 transcription in the context of MG infection. Furthermore, upregulation of AhR:Arnt significantly induced gga-miR-451 and inhibited YWHAZ expression, suggesting that AhR:Arnt may play an anti-inflammatory role in MG infection. This discovery suggests that induced gga-miR-451 expression is modulated by AhR:Arnt in response to MG infection.

Highlights

MicroRNAs are composed of a large class of post-transcriptional regulators of gene expression, and the majority of miRNAs are originally transcribed in the nucleus RNA polymerase II
We found that aryl hydrocarbon receptor (AhR):aryl hydrocarbon receptor nuclear translocator (Arnt) was significantly up-regulated upon Mycoplasma gallisepticum (MG)-infected DF-1 cells and was a negative regulator of YWHAZ expression
To determine the kinetics of primary gga-miR-451 transcript and gga-miR-451 precursor after MG infection, DF-1 cells were infected with Mycoplasma gallisepticum HS strain (MG-HS) for the indicated times, with non-infected acting as the control group

Summary

Introduction

MicroRNAs (miRNAs) are composed of a large class of post-transcriptional regulators of gene expression, and the majority of miRNAs are originally transcribed in the nucleus RNA polymerase II. The RISC produces mature miRNA, which enables partial base pairing and negative regulation of protein synthesis and/or mRNA degradation in the majority of cases [1]. MiRNAs have been reported to regulate diverse developmental, physiological, and pathological processes including avian diseases [2]. Gga-miR-19a activates the NF-κB signaling pathway through targeting ZMYND11 and promotes the proliferation of chicken fibroblast (DF-1) cells upon Mycoplasma gallisepticum HS strain (MG-HS) infection [3]. Gga-miR-23b promotes the replication of Avian Leukosis virus by repressing the expression of IRF1 [4]. Gga-miR-375 inhibits cell proliferation in tumorigenesis post subgroup J avian leukosis virus infection [5]. The function of host miRNAs has been generally studied during various foreign pathogen infections, there is very limited knowledge on how the expression of miRNAs is triggered during these diseases

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