Supplementary Material for: TCN1 expression is increased in asthma

Introduction: Asthma is a chronic disease that affects populations worldwide. The purpose of this study was to investigate the expression of TCN1 in sputum and its correlation with inflammation and lung function in asthma. Methods: We recruited 141 subjects, detected TCN1 mRNA level by qRT-PCR, detected TCN1 protein expression by western-blot, detected TCN1 protein level by ELISA, and analyzed the correlation between TCN1 and FeNO, IgE, EOS%, lung functions and some Th2 cytokines. The diagnostic value of TCN1 was evaluated by ROC curve. The expression of TCN1 was further confirmed by human bronchial epithelial cell in vitro. Results: Compared with the health group, the expression of TCN1 in induced sputum cells increased in asthma group and was correlated with FeNO, IgE and EOS%. TCN1 level was also elevated in the induced sputum supernatant of asthma patients. The protein level of TCN1 in induced sputum supernatant was correlated with FeNO, IgE and PC-20, FEV1%pred, FEV1/FVC and some cytokines (IL-4, IL-5, IL-10, IL-13, MUC5AC). TCN1 was also differentially expressed in patients with different severity of asthma. Four weeks after ICS treatment, the expression of TCN1 in induced sputum supernatant increased. In vitro, the protein level of TCN1 in human bronchial epithelial cells’ supernatant increased after stimulated with IL-4 and IL-13. Conclusion: The expression of TCN1 was increased in asthma patients' sputum, and was positively correlated with some inflammatory markers, negatively correlated with lung function. TCN1 may be used as a potential biomarker for the diagnosis and treatment of asthma.