Divergent Roles of miR-3162-3p in Pulmonary Inflammation in Normal and Asthmatic Mice as well as Antagonism of miR-3162-3p in Asthma Treatment

Abstract

MicroRNA (miRNA) mimics or antagomirs hold great promise for asthma treatment compared with glucocorticoids as mainstay therapy for asthma. But the role of miRNA in regulating asthmatic inflammation is largely unclear. We previously reported that miR-3162-3p in the peripheral blood of children with asthma was obviously upregulated compared to that in healthy children. This study aimed to elucidate the role of miR-3162-3p in pulmonary inflammation in normal and asthmatic mice as well as preliminarily explore the potential of miR-3162-3p antagomir in asthma treatment. A noninvasive whole-body plethysmograph measured airway responsiveness. Both qRT-PCR and Western blot were used to detect the expression of miRNA, mRNA, or protein. Cells in bronchoalveolar lavage fluid were counted by platelet counting and Wright's staining. Inflammatory infiltration and mucus secretion were identified by hematoxylin and eosin and periodic acid-Schiff staining, respectively. Cytokines in the lungs were detected by ELISA. The miR-3162-3p mimic intraperitoneally administered to normal mice decreased β-catenin levels in the lungs without obviously altering the lung histology and cytokine levels. Antagonizing miR-3162-3p in ovalbumin-induced asthmatic mice effectively alleviated the typical features of asthma, such as airway hyper-responsiveness, airway inflammation, and Th1/Th2 cytokine imbalance, and concomitantly rescued the total and active β-catenin expression. Collectively, we discovered divergent roles of miR-3162-3p in lung inflammation between normal and asthmatic mice. The anti-inflammatory effects of the miR-3162-3p antagomir were comparable to those of glucocorticoid treatment. Our study helped in understanding the contribution of miRNAs to the pathogenesis of asthma.