| OBJECTIVE:IL-1R-associated kinase(IRAK)-M regulates lung immunity during asthmatic airway inflammation.The regulatory effect of IRAK-M differs when airway inflammation persists.A positive association between IRAK-M polymorphisms with childhood asthma has been reported.However,there is still a lack of studies on the relationship between the single nucleotide polymorphism of the IRAK-M gene and adult asthma.In this study,we investigated the role of IRAK-M in the susceptibility to aduit-onset asthma and the mechanism of transcriptional regulation of IRAK-M.Methods:(1)679 adults with asthma were collected from Peking Union Medical College Hospital and Civil Aviation General Hospital as the asthma group.669 healthy subjects were collected from the health center of this two hospital as the control group.9 SNPs in the IRAM-M genomic region were selected,and SNaPshot were used for peripheral blood SNP typing,and population-based case-control association analysis was performed.(2)Fluorescence quantitative PCR was used to compare IRAK-M mRNA expression in asthma patients between different alleles of rs1624395.(3)Using public database information to predict the transcription factor binding of rs1624395,and comparing the ability of rs1624395-A mutation or rs1624395-G mutant binding to the transcription factor c-Jun by EMSA technique.Results:(1)Two IRAK-M SNPs(rs1624395 and rs1370128)were significantly associated with adult asthma(OR=1.227/95%CI:1.054-1.428,p=0.008;OR=1.187;95%CI:1.020-1.381,p=0.027).Homozygous GG of rsl624395 and homozygous CC of rs1370128 were more common in adult-associated asthma patients(p=0.025 and p=0.009).Even after removing the effects of gender and age,this correlation still exists(p=0.003).Haplotype GTAT has a protective effect against asthma(p=0.0079).In addition,SNPs in the IRAK-M locus were associated with many asthma phenotypes,rs7970350 was significantly associated with blood eosinophil counts(p<0.05),rs2141709 was significantly correlate with airflow obstruction(FEV1 Act/Pre%and FEV3/FVC%)(p<0.05),rs1821777 was significantly associated with FEV1 Act/Pre%and serum IgE levels(p<0.05),and rsl624395 was significantly associated with serum IgE levels(p<0.05).(2)The mRNA level of IRAK-M transcript variant 1 in peripheral blood of asthma patients with rs1624395 AG or GG genotype was higher than that of AA genotype(p<0.001).The IRAK-M mRNA expression level of transcript variant 1 was increased,but no statistical difference was observed.(3)EMSA experiments showed that both the rs1624395-G mutant and the rs1624395-A mutant could bind to the transcription factor c-Jun;however,the band of rs1624395-G mutant binding to c-Jun was more obvious than that of rs1624395-A mutant.Conclusions:Our study confirmed that the IRAK-M single nucleotide polymorphism(rs1624395 and rs1370128)is associated with adult asthma patients in northern Chinese Han population for the first time.In this population,the rs1624395 G allele and the rsl370128 C allele are asthma risk alleles.A haplotype(GTAT)of IRAK-M may be a potential,and the protective factor could reduce the risk of asthma.Asthma patients carrying the rs1624395 G allele had a significant increase in the peripheral expression level of one of the transcriptional variants of IRAK-M.The results of EMSA experiments showed that the binding strength of rs1624395-G allele to c-Jun transcription factor was higher than that of rs1624395-A allele.This suggests that the rs1624395 locus is highly likely to be a functional variant that increases asthma susceptibility by altering the ability of c-Jun transcription factors binding to DNA.These findings provide a theoretical basis for understanding the role of IRAK-M in the pathogenesis of asthma,and also provide some inspiration for the treatment of asthma by targeting IRAK-M. |
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