Allele-specific micro-RNA-mediated regulation of ADAM33 in childhood allergic asthma.

Background and objective: A disintegrin and metalloprotease 33 (ADAM33) is associated with asthma susceptibility, and its genetic variations impact susceptibility and disease severity. However, the mechanisms remain unclear. This study aimed to investigate ADAM33 single nucleotide polymorphisms (SNPs) in childhood asthma susceptibility and explore their regulatory mechanisms.

Methods: Eleven selected SNPs in ADAM33 were genotyped and identified the association with asthma susceptibility. In the validation cohort, we measured plasma sADAM33 levels and compared them with disease severity among children with different SNP genotypes. Computational predictions identified miRNAs targeting the SNP, and the impact of the SNP on miRNA regulation was confirmed using a dual luciferase reporter system. Finally, we validated the regulatory role of miRNAs on ADAM33 expression using an in vitro model with upregulated ADAM33 expression.

Results: Only rs3918400 was associated with asthma susceptibility. In the validation cohort, children with allergic asthma exhibited higher plasma sADAM33 levels. Among asthmatic children, those with the rs3918400 CT/TT genotype had higher sADAM33 levels, poorer asthma control, more severe airway hyper-responsiveness, lower FEV₁% and higher dust mite-specific IgE activity compared to those with the CC genotype. miR-3928-5p bound strongly to the rs3918400 C allele and effectively reduced ADAM33 protein expression in CC genotype cells. However, the binding affinity of miR-3928-5p to the T allele was weaker, resulting in diminished negative regulation of protein expression.

Conclusion: The rs3918400 SNP affects the negative regulation of ADAM33 by miR-3928-5p, potentially participating in a complex interplay of processes related to childhood asthma susceptibility.