NF-?B Dependent IncRNA Regulates Post-transcriptional Regulation Of Inflammation Response Genes

The innate immune system acts as a first-line of defense against invading pathogens.TLRs/NF-?B signaling pathway plays an important role in the regulation of innate immunity and is precisely regulated.Large long-noncoding RNAs(lncRNAs)are emerging as key regulators of diverse cellular processes,such as development,differentiation and metabolism.Nevertheless,whether lncRNA-mediated gene regulation is involved in the fine-tuning of innate immnune responses against pathogen infection remains undefined.Our study seeks to clarify the role of a TLR4/NF-?B-dependent IncRNA in innate epithelial immune responses,and explores the mechanism of transcriptional regulation and its function in innate immunity.We identified several TLR4/NF-KB-dependent lncRNAs including FIRRE(functional intergenic repeating RNA element),and chose FIRRE for further investigation.We defined the molecular mechanisms by which TLR/NF-?B signaling pathway modulates transcription of FIRRE following LPS stimulation and investigated the role of FIRRE in regulation of inflammatory response genes in innate immune cells.The main results as follows:(1)We identified a subset of lincRNA genes as TLR4/NF-KB-responsive genes in human macrophage cells and intestinal epithelial cells.One of such TLR4-responsive lncRNAs is FIRRE.(2)We focused on the transcriptional regulation of FIRRE.There are two potential NF-B binding sites at the promoter region of FIRRE gene and p65 binding to one of NF-?B binding sites(-1720)mediates FIRRE upregulation in response to LPS stimulation.(3)FIRRE regulates the expression of some inflammation response genes.FIRRE influences the expression of IL12p40,VC AM1 and IL6.(4)We investigated the molecular mechanisms by FIRRE regulates the expression of inflammation response genes.Previous studies showed that FIRRE interacts with the nuclear-matrix factor hnRNPU.We confirmed the physical interaction of FIRRE and hnRNPU by RIP analysis in macrophage cells and intestinal epithelial cells upon TLR4 ligation.FIRRE and hnRNPU co-regulate the expression of VCAM1 and IL12p40 through targeting ARE with hnRNPU.(5)FIRRE is relatively conserved among human and mouse.These findings demonstrate that FIRRE specifically promotes the expression of selected inflammatory genes by enhancing their mRNA stability through interaction with hnRNPU.The outcome of the proposed studies is likely to reveal new mechanisms and regulatory networks in innate immune responses,relevant to the development of new therapeutic strategies aimed at blocking specific IncRNA/NF-?B-regulated reprogramming for microbial infection.