Reduced expression of growth differentiation factor 11 promoted the progression of chronic obstructive pulmonary disease by activating the AKT signaling pathway

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease, which is associated with significant mortality and costs. The molecular mechanisms underlying the roles of cigarette smoke (an accepted risk factor for COPD) and growth differentiation factor 11 (GDF11), which is reduced in patients with COPD, in the occurrence of COPD are unclear. The aim of the present study was to explore the function of GDF11 in the progression of COPD. Western blotting analysis was used to determine the expression levels of GDF11 in serum and primary lung mesenchymal cells from patients with COPD and the healthy people, and the effect of cigarette smoke extract (CSE) on the expression of AKT, p-AKT (Ser473), p-AKT (Thr308) and GDF11 was examined. The correlations between the expression level of GDF11 and the ratio of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), as well as GDF11 and p-AKT (Ser473 and Thr308) in vivo and in vitro were examined. GDF11 expression was decreased in COPD patients' serum and cells when compared with that from the healthy people, and it was positively correlated with the FEV1/FVC ratio. Exposure to CSE reduced the expression of GDF11 but increased the expression of p-AKT (Ser473 and Thr308). Together, the results suggested that CSE promoted the progression of COPD by downregulating the expression of GDF11, which then activated the AKT signaling pathway. This study suggests that GDF11 may be a novel target for the diagnosis and treatment of COPD.