CircRNA Expression Profile In CD4⁺T Cells Of Asthmatic Patients And The Role Of Hsa_circ₀005519 In Airway Inflammation Of Asthma

Background:The immune response mediated by CD4~+T cells plays an important role in airway inflammation of asthma.Circular RNAs(circ RNAs)are a class of non-coding RNAs(nc RNAs),which can participate in biological processes of immune cells and serve as novel biomarkers for the diagnosis and treatment of diseases.Based on the previous literatures,we hypothesized that circ RNAs in CD4~+T cells were involved in airway inflammation of asthma.Objective:In this study,we investigated the circ RNA expression profiles in CD4~+T cells.Furthermore,we aimed to determine the potential involvement of differentially expressed hsa＿circ＿0005519 in airway inflammation of asthma.Methods:The circ RNA expression profiles in CD4~+T cells were revealed by circ RNA microarray.Hsa＿circ＿0005519 expression in CD4~+T cells was confirmed in 65 asthmatic patients and 30 healthy subjects by q RT-PCR.Correlation assays between the expression of hsa＿circ＿0005519 and the clinical characteristics of asthmatic patients were performed.We used the upper quartile of hsa＿circ＿0005519 expression level in the healthy subjects as the cut-off point,the asthmatic patients were divided into low and high hsa＿circ＿0005519expression.Hsa＿circ＿0005519 expression in CD4~+T cells and PBMCs were determined in another cohort including 30 asthmatic patients and 24 controls.Correlation assays of hsa＿circ＿0005519 expressions between CD4~+T cells and PBMCs were performed.We screened for target mirco RNAs(mi RNAs)and genes of hsa＿circ＿0005519 through bioinformatic software and constructed the hsa＿circ＿0005519-mi RNA-m RNA/gene network.A dual luciferase reporter assay was used to further investigate the target of hsa＿circ＿0005519 in 293T cells.The KEGG signaling pathway of the target genes was analyzed to predict the possible function of hsa＿circ＿0005519.The role of hsa＿circ＿0005519 in proinflammatory cytokine expression was investigated in CD4~+T cells from asthmatic patients in vitro.Results:Hsa＿circ＿0005519 was up-regulated in CD4~+T cells of asthmatic patients.Hsa＿circ＿0005519 expression in CD4~+T cells were positively correlated with both the peripheral blood eosinophils ratio and the fractional exhaled nitric oxide(Fe NO),but not significantly correlated with the peripheral blood neutrophils ratio.Interestingly,when we used the upper quartile of hsa＿circ＿0005519 expression level in healthy subjects as the cut-off point,the asthmatic patients were divided into low and high hsa＿circ＿0005519expression subgroups.High hsa＿circ＿0005519 expression seemed to be correlated with higher Fe NO and higher ratio of peripheral blood eosinophils,but there was no significant difference in the peripheral blood neutrophils ratio.Hsa＿circ＿0005519 expressions between CD4~+T cells and PBMCs were concordant in asthmatic patients.We verified that hsa-let-7a-5p was a target of hsa＿circ＿0005519.Mechanistically,hsa＿circ＿0005519 might bind to hsa-let-7a-5p and relieve suppression for IL-13/IL-6 in CD4~+T cells.Conclusion:Our data suggested that hsa＿circ＿0005519 might induce IL-13 and IL-6expression by regulating hsa-let-7a-5p in CD4~+T cells to affect asthma.And hsa＿circ＿0005519 might be a potential biomarker for diagnosis and classification of asthma.