The effect of inhaled glucocorticoid therapy on serum proteomics of asthmatic patients

Abstract

To screen the biomarkers which may play important roles in the pathogenesis and therapy of asthma by using serum comparative proteomics. From June 2011 to September 2012, 30 chronic persistent asthmatic patients (asthma group) and 30 healthy controls (control group) were selected for study in our hospital. All the asthmatic patients were given 8 week-treatment with inhaled glucocorticoids (ICS). Then comparative proteomics were employed to identify differential proteins in serum samples from the control group, the asthma pre-treatment group and the asthma post-treatment group. The differential proteins which had significant differences before and after ICS therapy were selected for Western blot analysis and ELISA detection. Besides, the correlation between the differential proteins and IgE, eosinophils (EOS), neutrophil percentage(NEUT%), and FEV1% were analyzed. Eleven differential proteins were identified. Among them, heat shock protein 70 (HSP70), eosinophil chemotactic protein (Eotaxin) and vitamin D binding protein (VDBP) had significant differences in protein abundance before and after treatment. The differential expression of the 3 proteins in each group was confirmed by Western blot. ELISA data showed that the serum levels of HSP70 and Eotaxin were significantly higher in the asthma pre-treatment group [(439 ± 103)ng/L, (183 ± 79)ng/L] than those in the control group [(209 ± 58)ng/L, (91 ± 46)ng/L] (t = 5.281, 4.972, all P < 0.01), but significantly lower in the asthma post-treatment group[(247 ± 96) ng/L, (105 ± 58)ng/L] than those in the pre-treatment group (t = 4.157, 3.892, all P < 0.01). However, the serum level of VDBP was significantly lower in the asthmatics pre-treatment group [(318 ± 115)mg/L] than that in the control group [(541 ± 98)mg/L] (t = 3.878, P < 0.01), but significantly higher in the asthma post-treatment group[(479 ± 132)mg/L] than that in the pre-treatment group(t = 3.572, P < 0.01). The correlation analysis showed that HSP70 was correlated positively with IgE and NEUT%, but negatively with FEV1% (r = 0.568, 0.613, -0.516, all P < 0.01). Eotaxin was correlated positively with IgE and EOS, but negatively with FEV1% (r = 0.752, 0.826, -0.618, all P < 0.01). VDBP was correlated negatively with NEUT%, but positively with FEV1% (r = -0.537, 0.426, all P < 0.05). HSP70, Eotaxin, and VDBP may participate in the pathogenesis of asthma, and may become the potential targets for ICS therapy.