Protective Effect of Circular RNA (CircRNA) Ddx17 in Ovalbumin (OVA)-Induced Allergic Rhinitis (AR) Mice

CircARF3 Mitigates Allergic Rhinitis through Targeting microRNA-205-5p/Sirtuin 5 Axis

INTRODUCTION

Circular RNAs (circRNAs) are essential in the progression of allergic rhinitis (AR). The purpose of this research was to examine the role of circRNA ADP-ribosylation factor 3 (circARF3) in the pathogenesis of AR.

METHODS

To generate an animal model of AR, mice were treated with house dust mite (HDM), and mice nasal epithelial cells (NEpCs) were treated with IL-4/IL-13 to imitate the inflammatory damage of AR in vitro. Sanger sequencing, qRT-PCR, and RNAse R digestion assays all validated the circularization structure of circARF3. The levels of circARF3, miR-205-5p, and sirtuin 5 (SIRT5) were determined by qRT-PCR or Western blotting. Luciferase reporter, RNA immunoprecipitation, and pull-down experiments were used to investigate the regulatory network. Flow cytometry was used to investigate the rate of cell apoptosis, and Western blotting was used to determine the levels of apoptotic-related proteins (cleaved caspase 3, cleaved polyadenosine-diphosphate-ribose polymerase) and HMGB1, TLR4, and MyD88. Enzyme-linked immunosorbent assay was used to assess the inflammatory response. Hematoxylin-eosin staining and TUNEL were used to detect the histology of injury and apoptosis of nasal mucosa tissues.

RESULTS

CircARF3 and SIRT5 levels were reduced in HDM-treated animals and IL-4/IL-13-treated NEpCs, while miR-205-5p expression was increased. CircARF3 was generated by back-splicing exons 3-5 with a stable circular shape. CircARF3 overexpression mitigated IL-4/IL-13-induced apoptosis in NEpCs by inhibiting miR-205-5p. SIRT5 upregulation attenuated IL-4/IL-13-induced inflammatory injury in NEpCs, and SIRT5 knockdown induced opposite effects. miR-205-5p silencing reversed the effects of SIRT5 knockdown on IL-4/IL-13-induced inflammatory injury. Furthermore, circARF3 overexpression alleviated histological abnormalities, apoptosis, inflammatory response, and HMGB1/TLR4 signaling activation in HDM-treated animals.

CONCLUSION

CircARF3 inhibited cell apoptosis and inflammation via the miR-205-5p/SIRT5 axis in IL-4/IL-13-treated NEpCs and HDM-treated mice.

Bioinformatics analysis of mRNA profiles and identification of microRNA-mRNA network in CD4+ T cells in seasonal allergic rhinitis

Objective

We aimed to discover potential circulating genes and non-coding molecules (micro RNA [miRNA] and circular RNA [circRNA]) in CD4⁺ T cells in relation to seasonal allergic rhinitis (SAR).

Methods

Microarray data of GSE50223 were obtained from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) during and outside the pollen season were analyzed using R software and by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analyses. The protein–protein interactions, modules, miRNAs targeting DEGs, merged miRNA–DEG networks, and circRNAs targeted with miRNAs were further analyzed.

Results

We identified 211 DEGs during the pollen season and eight DEGs outside the season, of which only MMP12, NR4A2, and CD69 were differentially expressed both during and outside the pollen season. DEGs during the pollen season were enriched in the GO categories ‘neutrophil degranulation’, ‘neutrophil activation involved in immune response’, ‘neutrophil mediated immunity’, and ‘neutrophil activation’. A significant module was identified with key nodes of CDK6 and hsa-miR-29b-3p. Six significant circRNAs were also identified.

Conclusions

Some genes, miRNAs, and circRNAs in CD4⁺ T may play vital roles in SAR and may thus be potential targets for the prevention and treatment of SAR.

Circ_0067835 regulates allergic inflammatory response in type-2 innate lymphoid cells in allergic rhinitis (AR) via miR-155/GATA3

Allergic rhinitis (AR) is a familiar respiratory allergic inflammatory disease with higher incidence. The pathogenesis of AR is particularly complex. Therefore, a lot of work is acquired to excavate deep mechanisms, thereby providing effective strategies for AR diagnose and treatment. AR mice model was induced by recombinant murine IL-33 (0.05 µg/µl) on days 1, 3, and 5. The lentiviral vectors carrying si-circ_0067835, miR-155 mimic, si-NC or miR-NC were injected into AR mice. Thus, mice were divided into control, AR, AR + si-NC, AR + si-circ_0067835, AR + si-circ_0067835 + miR-NC, and AR + si-circ_0067835 + miR-155 mimic groups. qRT-PCR experiment was used to measure the expression of circ_0067835 and miR-155. Behavioral test result was quantified to assess AR mice model. Hematoxylin and eosin (HE) staining was performed to analyze histopathological changes. Helper T cell 2 (Th2) cytokines (IL-4, IL-5, IL-9 and IL-13) and percentage of type-2 innate lymphoid cells (ILC2s) in nasal mucosa tissues in AR mice model were evaluated needing western blot, ELISA, and flow cytometry. Besides, the targeting relationship between circ_0067835 and miR-155, or between miR-155 and GATA3, was investigated via luciferase report assay. Circ_0067835 expression levels were raised in the nasal mucosa tissues of AR mice. Inhibiting circ_0067835 could reduce Type2 cytokines and ILC2s levels in AR mice model. Furthermore, circ_0067835 targeted and positively regulated miR-155 expression, and GATA3 was a downstream target of miR-155 and adjusted by circ_0067835/miR-155 axis. In addition, silencing circ_0067835 inhibited cytokines and ILC2s levels by down-regulating miR-155. Circ_0067835 effectively inhibited AR response in ILC2s through participation of miR-155/GATA3 axis.

CircRNA expression profiles and circRNA-miRNA-mRNA crosstalk in allergic rhinitis

Background

Circular RNAs (circRNAs) are involved in inflammation; however, their role in allergic rhinitis (AR) remains unclear. In this study, we analyzed circRNA expression and identified a circRNA-miRNA-mRNA network through which circRNAs regulate AR pathogenesis.

Methods

We analyzed circRNA, miRNA, and mRNA expression profiles in the nasal mucosa by high-throughput sequencing (HTS), using a fold-change >1.5 and p-value < 0.05 to pinpoint significantly differentially expressed (DE) circRNAs, miRNAs, and mRNAs in AR. A DEcircRNA-DEmiRNA-DEmRNA crosstalk network was then constructed using bioinformatics and statistical analysis. Gene ontology and Kyoto encyclopedia of genes and genomes pathway analyses were performed to identify the biological terms enriched in the network; whereas RT-PCR and Sanger sequencing were used to confirm the circRNAs.

Results

A total of 264 DEcircRNAs were identified by HTS, including 120 upregulated and 144 downregulated in AR compared to controls. A DEcircRNA-DEmiRNA-DEmRNA crosstalk network was constructed with 17 miRNAs, 11 circRNAs, 29 mRNAs, and 64 interaction pairs. These genes were involved in the Wnt signaling pathway, TNF biosynthesis, inflammatory responses, the PI3K-Akt signaling pathway, and Toll-like receptors. Of the 11 DEcircRNAs, hsa_circ_0008668 and circTRIQK were upregulated, whereas hsa_circ_0029853 and circRNA_01002 were downregulated in AR tissues. Sanger sequencing confirmed the back-splicing junctions of these circRNAs.

Conclusions

We constructed a novel DEcircRNA-DEmiRNA-DEmRNA network for AR that provides a basis for future studies to investigate its underlying molecular mechanisms.

Targeting a novel hsa_circ_0000520/miR-556-5p/NLRP3 pathway-mediated cell pyroptosis and inflammation attenuates ovalbumin (OVA)-induced allergic rhinitis (AR) in mice models

OBJECTIVES

The circRNAs-miRNAs-mRNAs competing endogenous RNA (ceRNA) networks involve in regulating the development of various inflammation-associated diseases, including allergic rhinitis (AR), and the present study aimed to identify novel AR-associated ceRNA networks.

METHODS

The mRNA and protein levels of the associated genes were, respectively, examined by real-time qPCR and western blot analysis. The targeting sites in miR-556-5p and NLRP3 were validated by performing dual-luciferase reporter gene system assay. ELISA was used to measure inflammatory cytokines secretion, and CCK-8 assay was conducted to determine cell proliferation.

RESULTS

Here, we first identified a hsa_circ_0000520/miR-556-5p/NLRP3 signaling cascade triggered epithelium pyroptosis and inflammation to regulate the development of AR in cellular and mice models. Specifically, the pyroptosis-associated biomarkers (NLRP3, ASC, IL-1β and IL-18) and pro-inflammatory cytokines (OVA-specific IgE, TNF-α, IL-4 and IL-5) were upregulated in the nasal subjects collected from AR patients and ovalbumin (OVA)-induced AR mice models, compared to their normal counterparts. Next, using the ceRNA networks analysis software, we screened out a hsa_circ_0000520/miR-556-5p axis that potentially regulated NLRP3 in the human nasal epithelial cell line. Mechanistically, miR-556-5p targeted both hsa_circ_0000520 and 3' untranslated region (3'UTR) of NLRP3, and knock-down of hsa_circ_0000520 inactivated NLRP3-mediated epithelium pyroptosis through miR-556-5p in a ceRNA-dependent manner. Furthermore, we proved that both hsa_circ_0000520 ablation and miR-556-5p overexpression suppressed NLRP3-mediated cell pyroptosis to attenuate AR in mice models.

CONCLUSIONS

Taken together, we evidenced that targeting the hsa_circ_0000520/miR-556-5p/NLRP3 signaling pathway was a novel AQ1strategy to ameliorate AR progression; however, future clinical data are still required to validate our preliminary results.

circARRDC3 contributes to interleukin‑13‑induced inflammatory cytokine and mucus production in nasal epithelial cells via the miR‑375/KLF4 axis

Allergic rhinitis (AR) is a common inflammatory disorder of the nasal mucosa. It is a major risk factor for asthma development, and uncontrolled AR can lead to the worsening of asthma symptoms, which affects the quality of life and productivity of patients. Circular RNAs (circRNA) were reported to be involved in the pathogenesis of AR. The aim of the present study was to investigate the functional role of circRNA arrestin domain-containing 3 (circARRDC3) in AR progression. circARRDC3 knockdown suppressed the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and eotaxin and mucin 5AC (MUC5AC) in IL-13-induced nasal epithelial cells. Moreover, circARRDC3 silencing promoted viability and suppressed apoptosis in IL-13-induced NECs. circARRDC3 targeted microRNA (miR)-375 and negatively regulated its expression. miR-375 inhibition reversed the effects of circARRDC3 knockdown on GM-CSF, eotaxin and MUC5AC expression levels, cell viability and cell apoptosis. In addition, miR-375 inhibited krueppel-like factor 4 (KLF4) expression through direct interaction, and miR-375 overexpression inhibited GM-CSF, eotaxin and MUC5AC expression levels, and cell apoptosis, which was abolished following KLF4 overexpression. In addition, circARRDC3, miR-375 and KLF4 were all dysregulated in the nasal mucosa of patients with AR. miR-375 expression was negatively correlated with circARRDC3 and KLF4 expression, and circARRDC3 expression was positively correlated with KLF4 expression. In conclusion, circARRDC3 contributed to the development of AR by regulating the miR-375/KLF4 axis. These findings may provide novel insights into the pathogenesis of AR.