Protective impacts of long noncoding RNA taurine-upregulated 1 against lipopolysaccharide-evoked injury in MRC-5 cells through inhibition of microRNA-127.

BACKGROUND: Pneumonia is a respiratory disease, which is triggered by pathogenic microorganisms or physical/chemical factors. Increasing evidence confirmed the vital impacts of long noncoding RNAs on various inflammatory diseases. Nonetheless, the influence of taurine-upregulated 1 (TUG1) in pneumonia remains vague. The research tried to disclose the protective impacts of TUG1 against lipopolysaccharide (LPS)-evoked injury in MRC-5 cells. METHODS: MRC-5 cells were disposed with LPS to construct pulmonary injury model. Then, pc-TUG1 vector was transfected into MRC-5 cells and the influence of overexpressed TUG1 in cell viability, apoptosis, and pro-inflammatory cytokines in LPS-disposed cells were evaluated. The correlation between TUG1 and microRNA (miR)-127 was estimated via utilizing real-time quantitative polymerase chain reaction (RT-qPCR), meanwhile whether miR-127 affected the impacts of TUG1 on LPS-injured MRC-5 cells was explored. Besides, NF-κB and p38MAPK pathways were evaluated to understand the dormant mechanisms. RESULTS: LPS administration apparently evoked inflammatory injury in MRC-5 cells by restraining cell viability, accelerating apoptosis, and enhancing TNF-α and IL-6 productions. But, TUG1 lightened LPS-evoked pro-inflammatory response in MRC-5 cells. In addition, miR-127 was repressed by overexpressed TUG1, meanwhile the protective impacts of TUG1 against LPS-evoked inflammatory injury in MRC-5 cells were overturned by overexpressed miR-127. Finally, we disclosed that TUG1 hindered the activation of NF-κB and p38MAPK pathways via restraining miR-127. CONCLUSIONS: These explorations testified that taurine-upregulated 1 (TUG1) protected MRC-5 cells against lipopolysaccharide (LPS)-evoked inflammatory injury via hindering miR-127/NF-κB/p38MAPK axis.

Expression of DACT1 in children with asthma and its regulation mechanism.

The aim of the present study was to detect DACT1 expression levels in the lungs of children with asthma, and to investigate its role and molecular mechanisms in regulating the expression of inflammatory factors in RAW264.7 cells. DACT1, DACT2 and DACT3 expression was analyzed in biopsy specimens from 10 cases of newly diagnosed children with asthma and 10 healthy controls by reverse transcription-quantitative polymerase chain reaction, and their expression was confirmed in RAW264.7 cells. DACT1 expression was silenced by small interfering RNA or enhanced by transfection of pcDNA-3.1-DACT1 in RAW264.7 cells, and expression of ß-catenin and inflammatory factors, interleukin (IL) 5, IL6 and IL13, was analyzed. Nuclear translocation of ß-catenin was detected by western blot analysis, and the effect of DACT1 on ß-catenin was investigated with rescue experiments. Regulation of the Wnt signaling pathway by DACT1 and ß-catenin was analyzed in RAW264.7 cells after recombinant Wnt5A stimulation. DACT1, DACT2 and DACT3 were significantly upregulated in specimens from children with asthma compared with controls (P<0.05) and the expression of DACT1 was significantly more increased compared with DACT2 and DACT3 (P<0.05). Inhibition of DACT1 expression significantly suppressed IL5, IL6 and IL13 mRNA expression levels compared with the control (P<0.05), while upregulated DACT1 expression significantly increased IL5, IL6 and IL13 mRNA expression (P<0.05). DACT1 inhibited the expression and nuclear translocation of ß-catenin, while overexpression of ß-catenin significantly inhibited the biological function of DACT1 (P<0.05). Overexpression of ß-catenin also significantly suppressed the upregulation of IL5, IL6 and IL13 mRNA induced by pcDNA3.1-DACT1 transfection (P<0.05). Following the addition of Wnt5A, overexpression of DACT1 inhibited the expression and nuclear translocation of ß-catenin, and upregulated IL5, IL6 and IL13 mRNA expression. In conclusion, DACT1 was indicated to be upregulated in lung tissues from children with asthma, which could induce higher pro-inflammatory factor expression. DACT1 may act via inhibiting the expression and nuclear translocation of ß-catenin, a factor in the Wnt signaling pathway. The present results suggested that DACT1 may be a potential target for the treatment of asthma.

Chronic intermittent hypoxia exposure induces memory impairment in growing rats.

The study was aimed to examine the effect of chronic intermittent hypoxia (CIH) on spatial memory of growing rats and to explore the possible underlying mechanisms. Sixty two rats were trained to perform the 8-arm radial maze task and were divided into four groups: 2-week-CIH (2IH) 2-week-control (2C) 4-week-CIH (4IH) and 4-week-control (4C). There were more reference memory errors, working memory errors and total memory errors in 2IH and 4IH groups compared to the controls. The levels of 8-iso-Prostaglandin F(2-alpha) [8-ISO-PGF(2-alpha)] an in vivo marker for oxidative stress, in serum, hippocampus and prefrontal cortex were higher in CIH groups than the control groups. There were significant correlations between the levels of 8-ISO-PGF(2-alpha) and numbers of memory errors. The ultrastructural changes were evident in the hippocampal and prefrontal cortical tissues from the CIH groups. These results indicate that CIH can induce oxidative stress in brain tissues involved in spatial memory function.

[The effect of chronic intermittent hypoxia on p38MAPK in cerebral tissues of weanling rats].

AIM: To study the effect of chronic intermittent hypoxia on p38MAPK in partial cerebral tissues of weanling rats. METHODS: Randomly, fifty male SD rats (3-week-old-4-week-old) were divided into five groups: 2-week-CIH group (2IH), 4-week-CIH group (4IH), 4-week-recovery group (4F), 2-week-control group (2C) and 4-week-control group (4C). Intermittent hypoxia model was induced by an intermittent hypoxia cabin. The expression of p38MAPK mRNA and the phosphorylation levels of p38MAPK (p-p38 protein) in the hippocampus and prefrontal cortex were measured by RT-PCR or Western blot respectively. RESULTS: No matter in the hippocampus, or in the prefrontal cortex, the expression of p38MAPK mRNA and p-p38 protein in 2IH, 4IH and 4F groups were respectively higher than 2C and 4C groups (P < 0.05, respectively). CONCLUSION: Chronic intermittent hypoxia can activate the p38MAPK in partial cerebral tissues of weanling rats.