[The role and mechanism of autophagy in lipopolysaccharide-induced inflammatory response of A549 cells]. / 自噬在脂多糖诱导的A549ç»†èƒžç‚Žç—‡ååº”ä¸­çš„ä½œç”¨åŠæœºåˆ¶ç ”ç©¶.

OBJECTIVES: To study the role and mechanism of autophagy in lipopolysaccharide (LPS)-induced inflammatory response of human alveolar epithelial A549 cells. METHODS: A549 cells were stimulated with LPS to establish a cell model of inflammatory response, and were then grouped (n=3 each) by concentration (0, 1, 5, and 10 µg/mL) and time (0, 4, 8, 12, and 24 hours). The A549 cells were treated with autophagy inhibitor 3-methyladenine (3-MA) to be divided into four groups (n=3 each): control, LPS, 3-MA, and 3-MA+LPS. The A549 cells were treated with autophagy agonist rapamycin (RAPA) to be divided into four groups (n=3 each): control, LPS, RAPA, and RAPA+LPS. The A549 cells were transfected with the Toll-like receptor 4 (TLR4) overexpression plasmid to be divided into four groups (n=3 each): TLR4 overexpression control, TLR4 overexpression, TLR4 overexpression control+LPS, and TLR4 overexpression+LPS. The A549 cells were transfected with TLR4 siRNA to be divided into four groups (n=3 each): TLR4 silencing control,TLR4 silencing, TLR4 silencing control+LPS, and TLR4 silencing+LPS. CCK-8 assay was used to measure cell viability. Western blot was used to measure the protein expression levels of inflammatory indicators (NLRP3, Caspase-1, and ASC), autophagic indicators (LC3B, Beclin-1, and P62), and TLR4. RESULTS: After stimulation with 1 µg/mL LPS for 12 hours, the levels of inflammatory indicators (NLRP3, Caspase-1, and ASC), autophagic indicators (LC3B, Beclin-1, and P62), and TLR4 increased and reached the peak (P<0.05). Compared with the LPS group, the 3-MA+LPS group had reduced expression of autophagy-related proteins and increased expression of inflammation-related proteins and TLR4, while the RAPA+LPS group had increased expression of autophagy-related proteins and reduced inflammation-related proteins and TLR4 (P<0.05). The TLR4 overexpression+LPS group had reduced autophagy-related proteins and increased inflammation-related proteins compared with the TLR4 overexpression control+LPS group, and the TLR4 silencing+LPS group had increased autophagy-related proteins and reduced inflammation-related proteins compared with the TLR4 silencing control+LPS group (P<0.05). CONCLUSIONS: In the LPS-induced inflammatory response of human alveolar epithelial A549 cells, autophagic flux has a certain protective effect on A549 cells. TLR4-mediated autophagic flux negatively regulates the LPS-induced inflammatory response of A549 cells.

Melatonin enhances autophagy and decreases apoptosis induced by nanosilica in RAW264.7 cells.

Melatonin is one of the main hormones that regulate biological rhythms and have immunomodulation, anti-inflammatory, and antioxidation functions. In this study, we aimed to explore the effect of melatonin on the autophagy, apoptosis, and inflammatory reaction of macrophages (RAW264.7 cells) stimulated by nanosilica. SiO2 (100 mg/mL, 10-20 nm) was used to stimulate RAW264.7 cells at different time points (0, 2, 4, 8, 12, and 24 hr). Melatonin (200 µM) was added to SiO2 -stimulated macrophages at 12 hr. Beclin-1, LC3, Bax, Bcl-2, and Caspase-3 were examined with western blotting. Flow cytometry was used to detect apoptosis. The levels of TNF-α, IL-1ß, and IL-18 were detected by ELISA. The level of TNF-α in the supernatant of SiO2 -stimulated cells gradually increased with time but decreased following melatonin administration. In contrast, the expression of IL-1ß and IL-18 increased after melatonin treatment. LC3 and Bax signaling pathways were activated in SiO2 -stimulated RAW264.7 cells, showing elevated expression of LC3 and reduced expression of Bax in the melatonin-treated cells. GFP-LC3 puncta were significantly increased in SiO2 -stimulated RAW264.7 cells and decreased in melatonin-treated cells. The apoptotic rate in SiO2 -stimulated RAW264.7 cells increased with time and decreased after melatonin treatment, and the number of phagosomes increased with the stimulation of nanosilica and the treatment of melatonin. Melatonin might promote autophagy and inhibit apoptosis as well as inflammatory responses of RAW264.7 cells stimulated by nanosilica. © 2019 IUBMB Life, 2019.

RNA sequencing and bioinformatics analysis of circular RNAs in asphyxial newborns with acute kidney injury.

As one kind of novel noncoding RNA, circular RNAs (circRNAs) are involved in different biological processes. Although growing evidences have supported the important role of circRNAs in renal diseases, the mechanism remains unclear in neonatal acute kidney injury (AKI). High-throughput sequencing analysis was used to investigate the expression of circRNAs between hypoxia-induced AKI neonates and controls. Bioinformatics analysis was conducted to predict the function of differentially expressed circRNAs. Finally, the differentially expressed circRNAs were screened and determined by quantitative real-time PCR (qPCR). (1) A total of 296 differentially expressed circRNAs were identified (Fold change >2 and p < 0.05). Of them, 184 circRNAs were markedly upregulated, and 112 were significantly downregulated in the AKI group. (2) The pathway analysis showed that ubiquitin-mediated proteolysis, renal cell carcinoma, Jak-STAT, and HIF-1 signaling pathways participated in AKI. (3) Top five upregulated and five downregulated circRNAs with higher fold changes were selected for qPCR validation. Hsa_circ_0008898 (Fold Change = 5.48, p = 0.0376) and hsa_circ_0005519 (Fold Change = 4.65, p = 0.0071) were significantly upregulated, while hsa_circ_0132279 (Fold Change = -4.47, p = 0.0008), hsa_circ_0112327 (Fold Change = -4.26, p = 0.0048), and hsa_circ_0017647 (Fold Change = -4.15, p = 0.0313) were significantly downregulated in asphyxia-induced AKI group compared with the control group. This study could contribute to future research on neonatal AKI and facilitate the identification of novel therapeutic targets.

Particulate matters induce acute exacerbation of allergic airway inflammation via the TLR2/NF-κB/NLRP3 signaling pathway.

BACKGROUND: Exposure to particulate matters (PMs) can lead to an acute exacerbation of allergic airway diseases, increasing the severity of symptoms and mortality. However, little is known about the underlying molecular mechanism. This study aimed to investigate the effects of PMs on acute exacerbation of allergic airway inflammation and seek potential therapeutic targets. METHODS: Non-allergic control and ovalbumin (OVA)-allergic wide-type (WT) and Toll-like receptor 2 knockout (Tlr2-/-) mice were exposed to 100 µg of PM (diameter 5.85 µm) or saline by the oropharyngeal instillation. The responses were examined three days after exposure. In the RAW264.7 macrophage cell line, Tlr2 was knocked down by small-interfering RNA or the NF-κB inhibitor JSH-23 was used, and then the cells were stimulated with PMs for 12 h before comparison of the inflammatory responses. RESULTS: PM exposure led to increased inflammatory cell recruitment and airway intensity of PAS + staining in OVA-allergic WT mice, accompanied with an accumulation of inflammatory cells and elevated inflammatory cytokines, such as IL-6 and IL-18, in the bronchoalveolar lavage fluid (BALF). Furthermore, the protein levels of TLR2 and the NLRP3 inflammasome were elevated concomitantly with the airway inflammation post-OVA/PMs challenge. Tlr2 deficiency effectively inhibited the airway inflammation, including pulmonary inflammatory cell recruitment, mucus secretion, serum OVA-specific immunoglobulin E (IgE), and BALF inflammatory cytokine production. Additionally, the P-induced NLRP3 activation in the RAW 264.7 cell line was diminished by the knockdown of Tlr2 or JSH-23 treatment in vitro. CONCLUSION: Our results indicated that PMs exacerbate the allergic airway inflammation mediated by the TLR2/ NF-κB/NLRP3 signaling pathway. Inhibition of NF-κB seems to be a possible treatment.