Effect of silencing FABP3 gene on LPS-induced apoptosis and endoplasmic reticulum stress in alveolar epithelial cells

Abstract

Objective: To investigate the effect of silencing fatty acid binding protein 3 (FABP3) gene on lipopolysaccharide (LPS)-induced apoptosis and endoplasmic reticulum stress in alveolar epithelial cells A549. Methods: According to the processing method, A549 cells were divided into control group(A549 cells cultured for 24 h), LPS group (10 mg/L LPS treated A549 cells for 24 h), LPS+si-con group (10 mg/L LPS was used to treat A549 cells transfected with si-con for 24 h) and LPS+si-FABP3 group (10 mg/L LPS was used to treat A549 cells transfected with si-FABP3 for 24 h). Then quantitative real-time PCR was used to detect the level of FABP3, methylthiazoletrazolium was used to detect the cell proliferation, flow cytometry was used to detect the apoptosis, and Western Blot was used to detect the levels of FABP3, CyclinD1, cleaved-caspase-3, GRP78, ATF4, CHOP, cleaved-caspase-12 and p-Akt and PI3Kp110α protein expression. Enzyme-linked immunosorbent assay was used to detect the levels of IL-6, IL-8 and TNF-αlevels. Results: In the LPS group, FABP3 protein level (1.00±0.09) and mRNA (2.15±0.22), apoptosis rate [(26.1±2.6)%], inflammatory factor IL-6 [(554.4±55.4) ng/L], IL-8 [(389.3±38.5) ng/L] and TNF-α [(601.3±60.0) ng/L], cleaved-caspase-3 (1.00±0.11), GRP78 (1.05±0.11), ATF4 (1.20±0.12)), CHOP (1.05±0.10), cleaved-caspase-12 (1.10±0.11), p-Akt (0.88±0.08) and PI3Kp110α (0.75±0.08) protein levels were significantly higher than the control group [(0.53±0.05), (1.00±0.10), (4.5±0.5)%, (75.4±7.5) ng/L, (25.2±2.5) ng/L, (66.5±6.7) ng/L, (0.34±0.05), (0.35±0.05), (0.43±0.05), (0.37±0.04), (0.45±0.05), (0.16±0.04), (0.35±0.05)] (all P<0.05). Cell viability [(50.1±5.4)%] and CyclinD1 protein level (0.40±0.05) in LPS group were significantly lower than those in the control group [(100.1±12.4)%, (1.25±0.12)] (both P<0.05). Cell viability [(89.1±8.5)%] and CyclinD1 protein level (1.15±0.11) in LPS+si-FABP3 group were significantly higher than those in LPS+si-con group [(53.1±5.4)%, (0.42±0.05)] (both P<0.05). Apoptosis rate [(10.5±1.1)%], IL-6[(301.3±30.0) ng/L], IL-8[(189.4±19.0) ng/L], TNF-α [(400.1±40.1) ng/L], cleaved-caspase-3 (0.45±0.05), GRP78 (0.48±0.05), ATF4 (0.60±0.06), CHOP (0.55±0.05), cleaved-caspase-12 (0.60±0.06), p-Akt (0.50±0.05) and PI3Kp110α(0.45±0.05) in LPS+si-FABP3 group were significantly lower than those in LPS+si-con group [(28.1±2.8)%, (536.3±53.6) ng/L, (400.2±40.2) ng/L, (623.1±62.3) ng/L, (0.96±0.10), (1.02±0.10), (1.15±0.12), (1.10±0.11), (1.15±0.12), (0.90±0.09), (0.72±0.07)] (all P<0.05). Conclusion: Silencing FABP3 gene can inhibit LPS-induced alveolar epithelial cell apoptosis and endoplasmic reticulum stress, which may act by inhibiting the PI3K/Akt signaling pathway.