[Role of 14-3-3σgene in the regulation of endotoxin/lipopolysaccharide-induced inflammatory responses in human pulmonary epithelial cells].

Objective: To explore the mechanism of 14-3-3σgene in regulating inflammatory response of human pulmonary epithelial cells induced by endotoxin/lipopolysaccharide (LPS). Methods: (1) Cells of human normal pulmonary epithelial cell line BEAS-2B cultured in logarithmic growth period were collected and divided into control group and PCMV6-14-3-3σgroup using the random number table, with 3 wells in each group. Cells in control group were transfected with empty plasmid, and cells in PCMV6-14-3-3σgroup were transfected with PCMV6-14-3-3σplasmid. The protein expression of 14-3-3σin cell was detected by Western blotting at 48 hours after transfection. (2) Cells of human normal pulmonary epithelial cell line BEAS-2B cultured in logarithmic growth period were collected and divided into control group, PCMV6-14-3-3σgroup, PCMV6-14-3-3σ+ LPS group, and LPS group using the random number table, with 3 wells in each group. Cells in control group were transfected with empty plasmid for 42 hours. Cells in PCMV6-14-3-3σgroup were transfected with PCMV6-14-3-3σplasmid for 42 hours. Cells in PCMV6-14-3-3σ+ LPS group were stimulated with 1 µg/mL LPS (the same final mass concentration below) for 6 hours after being transfected with PCMV6-14-3-3σplasmid for 42 hours. Cells in LPS group were stimulated by LPS for 6 hours. The protein expressions of Bax and B-cell lymphoma-2 (Bcl-2) were detected by Western blotting, and the ratio of Bax to Bcl-2 was calculated. Apoptotic rate was detected by flow cytometry. The mRNA expressions of tumor necrosis factor alpha (TNF-α) and interleukin 1beta (IL-1ß) in cells were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction technique. Content of TNF-α and IL-1ß in cell culture supernatant was detected by enzyme-linked immunosorbent assay. Data were statistically analyzed with t test, one-way analysis of variance, and least significant difference test. Results: (1) At 48 hours after transfection, the protein expression of 14-3-3σin cells of PCMV6-14-3-3σgroup (1.05±0.03) was significantly higher than that in control group (0.78±0.04, t=5.41, P<0.01). (2) Compared with those in control group, the ratio of Bax to Bcl-2, apoptotic rate, mRNA expressions of TNF-α and IL-1ß, and content of TNF-α and IL-1ß in cell supernatant in PCMV6-14-3-3σgroup showed no significant difference (P>0.05); the above-mentioned indexes of cells in LPS group were significantly higher or increased (P<0.01). Compared with those in LPS group, the above-mentioned indexes of cells in PCMV6-14-3-3σ+ LPS group were significantly lower or decreased (P<0.01). Conclusions: 14-3-3σis a key factor in regulating apoptosis. It can alleviate the LPS-induced inflammatory responses by regulating the ratio of apoptotic regulators Bax to Bcl-2 and inhibiting apoptosis of human pulmonary epithelial cells.

[Advances in the research of effects of exosomes on acute lung injury].

Acute lung injury (ALI) is a clinically common critical disease with various treatment methods. Stem cell has drawn great attention for excellent performance in treatment of ALI. However, due to its high apoptosis rate, the further clinical application of stem cell is restricted. Exosomes are a kind of extracellular vesicles secreted by cells, which play important role in injury repair with further research about exosomes. This article reviews current situation, brief introduction to exosomes, repair effects of exosomes on ALI, and the potential signal pathway.