Silencing of FSTL1 Alleviated LPS-Induced Inflammatory Damage and Oxidative Damage in Human Bronchial Epithelial Cells via BMP4/KLF4 Axis

Abstract

<b><i>Introduction:</i></b> Childhood asthma is a common chronic inflammatory lung disease in children, among which airway inflammation is the main driving factor of asthma symptoms. Follistatin-like protein 1 (FSTL1) is involved in multiple inflammatory processes, but its role in airway inflammation has not been fully elucidated. <b><i>Methods:</i></b> We used lipopolysaccharide (LPS) to stimulate human primary bronchial epithelial (BEAS-2B) cells to establish an in vitro airway inflammation model. The expression of FSTL1 was detected by qPCR. Cell Counting Kit-8 and Annexin V-PI double staining was used to analyze the viability and apoptosis of BEAS-2B. The content of IL-6, IL-8 and TNF-α was determined by ELISA kit. Western blot was used to detect the protein expression level of the bone morphogenetic protein 4 (BMP4) and KLF4. The levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde were measured to assess oxidative stress. <b><i>Results:</i></b> The mRNA expression of FSTL1 was significantly increased in LPS-treated BEAS-2B cells. Silencing of FSTL1 inhibited the release of IL-6, IL-8, TNF-α, and cell apoptosis as well as enhanced the activities of SOD, CAT, and GSH-Px. Silencing of FSTL1 reversed the inflammatory state of cells by upregulating BMP4 and increasing the expression level of KLF4. <b><i>Conclusion:</i></b> Silencing of FSTL1 reduced LPS-induced BEAS-2B cell damage by regulating the BMP4/KLF4 axis. FSTL1 may be a potential target for the treatment of asthma.