Tespa1 Negatively Modulates Asthmatic Attack Is Associated with IL-4/STAT-6 Pathway of Mast Cell

Abstract

Background Thymocyte-expressed, positive selection-associated 1 (Tespa1) is a critical signaling molecule in thymocyte development. This study aimed to investigate the regulatory effect of Tespa1 on mast cells in the pathogenesis of asthma and its relationship with the interleukin (IL)-4 /signal transducers and activators of transcription 6 (STAT6) signaling pathway. Methods Tespa1 mRNA expression analysis and IgE levels were carried out using the induced sputum of 33 adults with stable asthma and 36 healthy controls. Tespa1-knockout mice (Tespa1-/-, KO) and C57BL/6 background (wild-type, WT) mice were sensitized and treated with ovalbumin (OVA) to establish an asthma model. Pathological changes, number and activity of mast cells, and changes in activity of the IL-4 /STAT-6 pathway in lung tissue were detected. The changes of enzyme activity and STAT6 activity after mast cell gene knockout were analyzed in vitro. The changes of enzyme activity and STAT6 activity after mast cell gene knockout were analyzed in vitro. The association between the Tespa1 and P-STAT6 was analyzed by immunoprecipitation method. Results Compared with the healthy controls, Tespa1 expression was decreased, and IgE levels were elevated in the sputum of asthmatic patients. Animal experiments showed that Tespa1-/-mice exhibited more severe in ammation, higher quantity of goblet cells and mast cells in the bronchium, and greater activity of mast cell tryptase, which is induced by ovalbumin, than WT mice. And IL-4, IL-13, phospho-Janus kinase 1, and P-STAT6 expressions presented a higher increase in the Tespa1-/-mouse model than in the WT mouse model. Further in vitro studies con rmed that IL-4 could more signi cantly promote tryptase and P-STAT6 activities in Tespa1-/-mast cells than their WT counterparts. Correlation analysis results showed a negative correlation between Tespa1 and P-STAT6. Immunoprecipitation results showed a direct link between Tespa1 and P-STAT6. Conclusions Altogether, our results indicate that Tespa1 can negatively regulate mast cell activity, and this event is related to the mast cell IL-4/STAT6 signaling pathway and could be therapeutically exploited to treat asthma attacks. Background Mast cells play an important role in the innate and adaptive immunities related to the pathophysiologic process of asthma. Mast cells not only act as effector cells during allergic reactions, but also perform a complex role in the induction and regulation of adaptive immune responses of asthma [1-3]. When an allergen enters the atopic patient, IgE is speci cally synthesized by B lymphocytes and bind to the higha nity IgE receptor (FcεRI) on the surface of mast cells and basophils [4, 5]. If the allergen re-enters the body, it can bind with IgE FcεRI on the mast cells, thus promoting cell activation, synthesizing and releasing various active mediators, such mediators as histamine, chemokine, neutrophil chemokine, prostaglandin [6, 7]. These mediators and cytokines play a pivotal role in the pathogenesis of asthma and in ammation. Interleu...