BACKGROUND/AIMS: β-arrestin2 has been shown to have a role in human inflammatory disease. However, the role of β-arrestin2 in cigarette smoke-induced inflammation in the lung remains unknown. The aims of this study were to investigate the effects of β-arrestin2 on cigarette smoke condensate (CSC)-induced expression of inflammatory cytokines in the BEAS-2B human bronchial epithelial cell line in vitro, and the mechanisms involved. METHODS: The MTT assay determined cell viability of cultured BEAS-2B cells. Autophagy was assessed by western blot, adenoviral mRFP-GFP-LC3 transfection, and immunofluorescence. The effects of β-arrestin2 shRNA knockdown were studied by western blot and real-time reverse transcription-polymerase chain reaction (RT-PCR). Western blot evaluated the AMPK/mTOR signaling pathway. Levels of inflammatory cytokines, interleukin (IL)-6, IL-8, and MCP-1 were measured in cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). RESULTS: CSC suppressed expression of β-arrestin2 in BEAS-2B cells, activated the AMPK/mTOR signaling pathway, increased cell autophagy and the expression of IL-6, IL-8, and MCP-1,pretreatment with the β-arrestin2 biased ligands, propranolol, and ICI118551 reversed these changes. Inhibition of autophagy reduced the expression of inflammatory cytokines following CSC. CONCLUSION: In the human bronchial epithelial cell line, BEAS-2B, β-arrestin2 reduced the expression of CSC-induced inflammatory cytokines by inhibiting autophagy, most likely via the AMPK/mTOR signaling pathway.
BACKGROUND/AIMS: β-arrestin2 has been shown to have a role in human inflammatory disease. However, the role of β-arrestin2 in cigarette smoke-induced inflammation in the lung remains unknown. The aims of this study were to investigate the effects of β-arrestin2 on cigarette smoke condensate (CSC)-induced expression of inflammatory cytokines in the BEAS-2B human bronchial epithelial cell line in vitro, and the mechanisms involved. METHODS: The MTT assay determined cell viability of cultured BEAS-2B cells. Autophagy was assessed by western blot, adenoviral mRFP-GFP-LC3 transfection, and immunofluorescence. The effects of β-arrestin2 shRNA knockdown were studied by western blot and real-time reverse transcription-polymerase chain reaction (RT-PCR). Western blot evaluated the AMPK/mTOR signaling pathway. Levels of inflammatory cytokines, interleukin (IL)-6, IL-8, and MCP-1 were measured in cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). RESULTS: CSC suppressed expression of β-arrestin2 in BEAS-2B cells, activated the AMPK/mTOR signaling pathway, increased cell autophagy and the expression of IL-6, IL-8, and MCP-1,pretreatment with the β-arrestin2 biased ligands, propranolol, and ICI118551 reversed these changes. Inhibition of autophagy reduced the expression of inflammatory cytokines following CSC. CONCLUSION: In the human bronchial epithelial cell line, BEAS-2B, β-arrestin2 reduced the expression of CSC-induced inflammatory cytokines by inhibiting autophagy, most likely via the AMPK/mTOR signaling pathway.
Authors: Bei Shi; Suxian Liu; Aoshuang Huang; Mengyun Zhou; Boyun Sun; Hui Cao; Jingyi Shan; Bo Sun; Jiang Lin Journal: Evid Based Complement Alternat Med Date: 2021-11-02 Impact factor: 2.629