Study On The Role And Mechanism Of IRAK-M In Airway Epithelial Inflammation In Asthm

Part 1:The role of IRAK-M in airway epithelial inflammation of asthma and the potential molecule mechanismObjective:Airway epithelium regulates downstream airway inflammation and immune response through toll-like receptors(TLRs),which participates in the innate and adaptive immunity of asthma.Interleukin-1 receptor-associated kinase M(IRAK-M)is a negative regulator of the TLR signaling pathway,which involves in the immunoregulation of airway inflammation by affecting the activation of macrophages and dendritic cells and T cells differentiation.However,whether IRAK-M has effect on cellular immunity in airway epithelial cells upon stimulation remains unclear.In this study,we investigated the effect of IRAK-M on airway epithelial cell inflammation induced by stimulation and its potential molecular mechanism.Methods:We down-regulated the expression of IRAK-M in human airway epithelial BEAS-2B cells and alveolar epithelial A549 cells by small interference RNA(siRNA),and the cellular inflammation models were established with interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),interleukin-33(IL-33)or house dust mite(HDM).The production of cytokines and the activation of signal pathways were used to reflect the effect of IRAK-M on airway epithelial inflammation.Results:IRAK-M expression was significantly induced in BEAS-2B cells and A549 cells after inflammatory stimulation.IRAK-M knockdown increased the lung epithelial production of cytokines and chemokines at both mRNA and protein levels,including interleukin-6(IL-6),interleukin-8(IL-8),C-X-C chemokine ligand 10(CXCL10)and CX-C motif chemokine ligand 11(CXCL11).But IRAK-M knockdown had no effect on IFN-y secretion.Upon stimulation,IRAK-M silencing led to overactivation of c-Jun Nterminal kinase(JNK)and p38 mitogen-activated protein kinase(MAPK)in pulmonary epithelial cells after inflammatory stimulation.While antagonizing JNK or p38 MAPK with SP600125,an inhibitor of the JNK pathway,or SB203580,an inhibitor of the p38 MAPK pathway,the upregulation of CXCL10 secretion by pulmonary epithelial cells induced by IRAK-M knockdown was partly inhibited.Conclusion:IRAK-M can regulate airway epithelial inflammation with an influence on the secretion of CXCL10 by pulmonary epithelial cells partly through JNK and p38 MAPK pathways.The regulation of IRAK-M provides a new idea for the study of the pathogenesis of asthma,and IRAK-M may become a new target for asthma treatment.Part 2:The relationship between IRAK-M single nucleotide polymorphism and serum CXCL10 levels in patients with asthmaObjective:Airway epithelial cells express a variety of asthma susceptibility genes including IRAK-M.IRAK-M single nucleotide polymorphisms(SNPs),rs1624395 and rs 1370128 were genetically associated with asthma in adults.Rs 1624395 had an effect on the level of IRAK-M mRNA in peripheral blood monocytes of patients with asthma.We found that IRAK-M can regulate the production and secretion of CXCL10 in airway epithelial cells by inflammatory stimulation.However,whether IRAK-M SNPs affects serum CXCL10 levels in patients with asthma is still unclear.In this study,we explored the correlation between IRAK-M SNPs,rs1624395,rs1370128 and serum CXCL10 levels in patients with asthma.Methods:We collected the peripheral blood cells and serum of adult asthma patients treated in the Asthma Clinic of Beijing Civil Aviation General Hospital from September 2021 to March 2022,and the clinical data including demographic data,complete blood count,serum IgE,pulmonary function test and medication history were collected,IRAKM SNPs,rs1624395 and rs1370128 were genotyped by SNaPshot.The concentration of serum CXCL10 in patients with asthma was determined by enzyme linked immunosorbent assay(ELISA).We analyzed the association between rs1624395 and rs1370128 genotypes and serum CXCL10 levels.Results:Peripheral blood cells and serum were collected from 137 adult patients with asthma.Rs1624395 is completely interlocked with rs1370128 and serum CXCL10 concentrations in all subjects was 40.7 ± 12.4 pg/ml.Asthma patients carrying G/G genotypes of rs1624395 had higher levels of serum CXCL10 than those carrying homozygote A/A(41.4± 7.8 pg/ml vs 38.1 ± 3.3 pg/ml,p=0.03).Conclusion:There is a correlation between IRAK-M SNPs and serum CXCL10 level in patients with asthma.The genetic study between IRAK-M and asthma can help us understand the pathogenesis of asthma and find new treatment for asthma.