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.

Downregulation of miR-96-5p Inhibits mTOR/NF-κb Signaling Pathway via DEPTOR in Allergic Rhinitis.

BACKGROUND: This study aims to investigate the regulatory effect of microRNA-96-5p (miR-96-5p) in the pathophysiological process of allergic rhinitis (AR). METHODS: Nasal mucosal tissue samples were collected from AR patients and healthy controls. An in vitro AR model was established by stimulating human nasal epithelial cells (HNECs) with interleukin (IL)-13. The expressions of target genes and proteins were measured by qPCR, Western blot, or ELISA. Dual-luciferase reporter assay and pull-down assay were performed to confirm the interaction between miR-96-5p and DEP domain-containing mammalian target of rapamycin-interacting protein (DEPTOR). RESULTS: The level of miR-96-5p was increased while the expression of DEPTOR was decreased in AR patients. The expressions of proinflammatory cytokines were markedly increased and the mammalian target of rapamycin (mTOR)/NF-κB pathway was activated in HNECs following IL-13 stimulation. miR-96-5p downregulation alleviated the stimulated function by IL-13. DEPTOR was the target of miR-96-5p. Knockdown of DEPTOR reversed the function of miR-96-5p inhibitor on IL-13-stimulated HNECs. CONCLUSIONS: The current study showed that miR-96-5p and DEPTOR were aberrantly expressed in AR nasal mucosa. miR-96-5p knockdown inhibited the production of inflammatory cytokines and the activation of mTOR/NF-κB pathway via targeting DEPTOR. These findings suggested that miR-96-5p might be used as a diagnostic marker and therapeutic target for the treatment of AR.