MicroRNAs are small yet versatile gene tuners that regulate a variety of cellular processes, including cellgrowth and proliferation. Here we report that miR-23b inhibited airway smooth muscle cells (ASMCs) proliferation through directly targeting of Smad3.
METHODS:
We obtained ASMCs by laser capture microdissection of normal and asthmatic micelungtissues. Mice ASMCs were cultured and induced by TGF-ß1. The implication between TGF-ß1 and miR-23b in ASMCs were detected by RT-PCR. The effects of miR-23b on ASMCs proliferation and apoptosis were assessed by transienttransfection of miR-23b mimics and inhibitor. The expression of Smad3 in ASMCs were detected by RT-PCR and Western blottinganalysis. Dual-Luciferase Reporter Assay System will be applied to identify whether Smad3 is a target gene of miR-23b.
RESULTS:
TGF-ß1 and miR-23b mRNA expression of in-situ bronchial ASMCs collected by laser capture microdissection were increased in asthmatic mice compared to non-asthma controls. This is accompanied by an increase in miR-23b mRNA expression in TGF-ß1 induced ASMCs. miR-23b up-regulation significantly inhibited TGF-ß1-induced ASMCs proliferation and promoted apoptosis. MiR-23b negatively regulates the expression of Smad3 in ASMCs. Dual-Luciferase Reporter Assay System demonstrated that Smad3 was a direct target of miR-23b.
CONCLUSIONS:
MiR-23b may function as an inhibitor of asthmaairway remodeling by suppressing ASMCs proliferation via direct targeting of Smad3.