MicroRNA-155 is a critical regulator of regulatory T cells in OM-85 Broncho-Vaxom treated experimental models of allergic rhinitis

Abstract

<abstract><sec> <title>Background</title> <p>Bacterial lysates could alleviate the clinical symptoms of allergic rhinitis (AR) and decrease the recurrent rate of AR through regulation of regulatory T cell (Treg) cells. However, the molecular regulatory mechanisms of bacterial lysates to Treg are still unclear.</p> </sec><sec> <title>Objective</title> <p>We aimed to investigate the importance of microRNA-155 (miR-155) to Treg cells function in OM-85 Broncho-Vaxom (OM-85 BV) treated experimental mouse models of AR.</p> </sec><sec> <title>Methods</title> <p>AR mouse models were established and treated by intranasal administration of OM-85 BV to investigate the role of bacteria lysate for Treg cell function. The proliferation of Treg cells in peripheral blood was examined. The mRNA levels of IL-10, transforming growth factor-β (TGF-β) were examined by real-time PCR. miR-155 mimics and inhibitor were used to verify the role of miR-155 for Treg cells function.</p> </sec><sec> <title>Results</title> <p>OM-85 BV, miR-155 mimics or their combination reduced total cells, lymphocytes, neutrophils and eosinophils in nasal lavage fluid of AR mouse models and improved allergic symptoms. OM-85 BV promoted the proliferation of Treg and the expression of Foxp3, IL-10 and TGF-β both <italic>in vivo</italic> and <italic>in vitro</italic>. The miR-155 enhanced the proliferation and function of Treg.</p> </sec><sec> <title>Conclusions</title> <p>MiR-155 promotes Treg cells function in OM-85 BV bacteria lysate treated experimental models of AR and alleviate the upper airway allergic inflammation in AR mice.</p> </sec></abstract>