To explore mechanisms in obesity-associated asthma using functional proteomics technology: A pilot study

Rationale: Obesity-associated asthma exhibits different clinical features such as neutrophilic airway inflammation and poor asthma control, but the mechanism has been unexplored largely. Objective: Proteomics analyses of peripheral blood mononuclear cells (PBMCs) and induced sputum cells were used to explore differential proteins between obese and normal-weight subjects with asthma. Methods: Nineteen with normal-weight asthma (NWA group) and 13 with obese asthma (OA group) were recruited. Demographic and clinical characteristics were collected. All subjects underwent sputum induction and extraction of peripheral venous blood samples. Tested proteome quantification iTRAQTM was used to screen differential proteins. Results: The number of neutrophils and monocytes in the OA group was higher than in NWA group in peripheral blood. The percentage of neutrophils in the NWA group was significantly lower than the OA group in induced sputum. In PBMCs, 111 differentially expressed proteins were identified between the two groups. The differentially expressed proteins were located in muscle thin filament tropomyosin and stress fiber, which had diverse biological functions including hemoglobin binding and oxygen binding. In induced sputum cells, 104 differential proteins were confirmed. These differentially expressed proteins were located in nucleosome and cellular macromolecular complex assembly. These differential proteins constituted one important pathway in PPAR signaling pathway. Conclusion: Our study has identified differential expressed proteins in PBMC and induced sputum in obese-asthma phenotype, which were associated with metabolic inflammatory pathways.