MicroRNA-216a Inhibits NF-κB-Mediated Inflammatory Cytokine Production in Teleost Fish by Modulating p65

Abstract

Inflammation is the host self-protection mechanism to eliminate pathogen invasion. The excessive inflammatory response can result in uncontrolled inflammation, autoimmune diseases, or pathogen dissemination. Recent studies have widely shown that microRNAs (miRNAs) contribute to the regulation of inflammation in mammals by repressing gene expression at the posttranscriptional level. However, the miRNA-mediated mechanism in the inflammatory response in fish remains hazy. In the present study, the regulatory mechanism of the miR-216a-mediated inflammatory response in teleost fish was addressed. We found that the expression of miR-216a could be significantly upregulated in the miiuy croaker after challenge with and lipopolysaccharide. Bioinformatics predictions demonstrated a potential binding site of miR-216a in the 3' untranslated region of the p65 gene, and the result was further confirmed by luciferase assay. Moreover, both the mRNA and protein levels of p65 in macrophages were downregulated by miR-216a. Deletion mutant analysis of the miR-216a promoter showed that the Ap1 and Sp1 transcription factor binding sites are indispensable for the transcription of miR-216a. Further study revealed that overexpression of miR-216a suppresses inflammatory cytokine expression and negatively regulates NF-κB signaling, which inhibit an excessive inflammatory response. The collective results indicate that miR-216a plays a role as a negative regulator involved in modulating the bacterium-induced inflammatory response.

Pro-inflammatory macrophages coupled with glycolysis remodel adipose vasculature by producing platelet-derived growth factor-B in obesity

“…The LPS-induced expression of Il6 was attenuated by the knockdown of p65 ( Fig. 5c,d), as previously reported 28 . However, the expression of Pdgfb was not suppressed in p65-knockdown macrophages (Fig.…”

Non-coding RNAs Function as Immune Regulators in Teleost Fish

“…More importantly, miR-192 was confirmed to regulate inflammatory immune responses in miiuy croaker with bacterial infection by targeting IL-1 receptor type I (IL-1RI). Another two miRNAs, miR-216a ( 15 ), and miR-203 ( 56 ), were obviously upregulated in miiuy croaker challenged with V. anguillarum and LPS. miR-216a caused p65 downregulation by binding to its 3′ untranslated region (3′ UTR).…”

“…LncRNAs have been found to be correlated with development and differentiation in teleost fish ( 12 , 13 ). More importantly, the functional role of miRNAs and lncRNAs in fish immune responses has also been disclosed in several species ( 13 – 15 ). miRNAs and lncRNAs may serve as critical regulators in cytokine and chemokine signaling, antigen presentation, complement and coagulation cascades, and T cell response in teleost fish.…”

MicroRNA regulation of Toll‐like receptor, RIG‐I‐like receptor and Nod‐like receptor pathways in teleost fish

“…Thus, there is mounting evidence that miRNA plays a vital role in the regulation of TLR‐induced transcription factors in mammals. In fish, our researches show that endogenous miR‐216a can negatively regulate NF‐κB signalling by directly targeting p65, thereby inhibiting excessive and prolonged inflammation (Xu et al 2018c). This is the first in‐depth study of miRNAs regulating TLR‐induced transcription factors in teleost fish.…”