CRYAB reduces cigarette smoke-induced inflammation, apoptosis, and oxidative stress by retarding PI3K/Akt and NF-κB signaling pathways in human bronchial epithelial cells

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a familiar airway disease characterized by chronic immune response in the lungs. More and more evidences have assured that cigarette smoking is the primary reason for the progression of COPD, but its related regulatory mechanism requires further clarification. The α-B-crystallin (CRYAB) has been identified to exhibit vital functions in different diseases, and is down-regulated in the alveoli of mice mediated by cigarette smoke extract (CSE). Methods: The messenger RNA expression of CRYAB was assessed by reverse transcription--quantitative polymerase chain reaction. The proteins’ expressions were tested using Western blot method. The cytotoxicity was measured by lactate dehydrogenase assay. The levels of malondialdehyde, superoxide dismutase, catalase, myeloperoxidase, tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 were assessed through enzyme-linked-immunosorbent serologic assay (ELISA). Results: In this study, it was discovered that the expression of CRYAB was markedly decreased with the increased time of cigarette smoking. Moreover, CRYAB overexpression increased cell viability and decreased cell apoptosis induced by cigarette smoke. In addition, the strengthened oxidative stress and inflammation mediated by CSE treatment was relieved after overexpression of CRYAB. Eventually, results OF Western blot method confirmed that CRYAB retarded the activation of phosphatidylinositol 3-kinase–Ak strain transforming (PI3K–Akt) and nuclear factor kappa B (NF-κB) signaling pathways. Conclusion: Our results manifested that CRYAB reduced cigarette smoke-induced inflammation, apoptosis, and oxidative stress in normal and diseased bronchial epithelial (NHBE) and human bronchial epithelial (BEAS-2B) cells by suppressing PI3K/Akt and NF-κB signaling pathways, which highlighted the functioning of CRYAB in preventing or treating COPD.