Effects and mechanism of arsenic trioxide on reversing the asthma pathologies including Th17-IL-17 axis in a mouse model.

In traditional Chinese medicine, arsenous compounds, including arsenic trioxide (ATO), are often used to treat many diseases, which are safe and effective. Recently, studies have indicated that Th17- IL-17 involved in the pathogenesis and development of asthma. The goal of this study was to investigate the effect and mechanism of ATO on asthma, especially the Th17- IL-17 axis.We used oval bumin (OVA)-immunized mice as a model for asthma and treated mice with ATO or dexamethasone. The mice were then monitored airway responsiveness, airway inflammation, mucus production, IL-17 levels in BALF and the positive rate of Th17 cells. In vitro, CD4+ T cells from splenic cell suspensions were separated and purified. We measured the expression of IL-17 and caspase-12 protein in purified CD4+ T cells, and detected IL-17 levels in CD4+ T lymphocyte culture solution with or without ATO. Moreover, apoptosis, mitochondrial membrane potential, cytosolic calcium were analyzed. We found that ATO could reduce airway responsiveness, airway inflammation, mucus hyperplasia, the expression of IL-17 in BALF and the positive rate of Th17 cells at a level comparable to treatment with DXM. In vitro data suggested that ATO can induce CD4+ T cells apoptosis, cause mitochondrial dysfunction, Ca2+ overload and promote caspase-12 activation. Our study suggested that ATO had potential medical value for the treatment of human asthma..

ß-arrestin2 stimulates interleukin-17 production and expression of CD4+ T lymphocytes in a murine asthma model.

Allergic asthma is a complex and chronic inflammatory airway disease. Interleukin-17 is a pro-inflammatory cytokine which plays critical role in the pathogenesis of allergic asthma. It has been reported that ß-arrestin2 regulated the development of allergic asthma at a proximal step in the inflammatory cascade. In this study, the influence of ß-arrestin2 on Interleukin-17 production and expression of CD4+ T lymphocytes in a murine asthma model was investigated. Splenic CD4+ T lymphocytes from wild-type mice and those from a murine asthma model were purified. CD4+ T lymphocytes from a murine asthma model were transfected with siRNAs targeting the ß-arrestin2 or were pretreated with the ERK1/2 inhibitor, PD98059. After stimulation, the protein expression of ß-arrestin2、phosphorylated-ERK1/2 and IL-17 were detection by Western blot; the mRNA expression of IL-17 were detected by real-time PCR; the accumulation of IL-17 in supernatants were detected by ELISA. We found that ß-arrestin2、phosphorylated-ERK1/2 and IL-17 expression in CD4+ T lymphocytes from a murine asthma model were increased compared with those from wild-type mice (p < 0.01). Treatment of CD4+ T lymphocytes with siRNAs targeting the ß-arrestin2 down-regulated phosphorylated- ERK 1/2 and IL-17 expression (p < 0.01). PD98059 decreased IL-17 production and expression in CD4+ T lymphocytes in a murine asthma model (p < 0.05). We conclude that ß-arrestin2 stimulated IL-17 production and expression of CD4+ T lymphocytes in a murine asthma model. The effect was partly mediated by ERK 1/2 activation. Targeting ß-arrestin2 biological activity could be a valid therapeutic approach for the treatment of allergic asthma.