[Role and mechanism of miRNA-181a in nonalcoholic fatty liver disease]

Objective: To investigate the role and probable mechanism of miRNA-181a in nonalcoholic fatty liver disease. Methods: HepG2 cells were treated with palmitic acid to construct a nonalcoholic fatty liver disease cell model, and the expression of miR-181a and lipidosis in the cells were measured. Transforming growth factor-β (TGF-β) was used to examine the effect of miR-181a expression in HepG2 cells. The miR-181a, lipidosis, reduced glutathione and reactive oxygen species (ROS) were determined by controlling and regulating the miR-183 expression levels after transfection with miR-181 mimics and inhibitors in HepG2 cells. The miR-181a target genes were predicted by bioinformatics analysis, and verified by real-time fluorescent quantitative PCR and western blotting. The independent sample t-test was used for the comparison between the two independent samples, and the comparison between multiple groups were accorded with the normal distribution, homogeneity of variance, and one-way analysis of variance. Results: Lipidosis was significantly increased after palmitic acid treatment in HepG2 cells, and the expression level of miR-181a was significantly increased than control group. After HepG2 cells were transfected with miR-181a inhibitors, the expression of miR-181a, triglycerides and reactive oxygen species were down-regulated, and reduced glutathione, predicting the mRNA and protein expression of target gene silencing information regulator 2 related enzyme 1 were up-regulated. However, the results were contrary to the above changes after transfection with miR-181a mimics. Conclusion: miR-181a participates in lipidosis and promotes lipid peroxidation in nonalcoholic fatty liver disease. miR-181a may affect the pathogenesis and progression of nonalcoholic fatty liver disease by inhibiting the expression of silencing information regulator 2 related enzyme 1.

Chromatin organisation in duckweed interphase nuclei in relation to the nuclear DNA content

The accessibility of DNA during fundamental processes, such as transcription, replication and DNA repair, is tightly modulated through a dynamic chromatin structure. Differences in large-scale chromatin structure at the microscopic level can be observed as euchromatic and heterochromatic domains in interphase nuclei. Here, key epigenetic marks, including histone H3 methylation and 5-methylcytosine (5-mC) as a DNA modification, were studied cytologically to describe the chromatin organisation of representative species of the five duckweed genera in the context of their nuclear DNA content, which ranged from 158 to 1881 Mbp. All studied duckweeds, including Spirodela polyrhiza with a genome size and repeat proportion similar to that of Arabidopsis thaliana, showed dispersed distribution of heterochromatin signatures (5mC, H3K9me2 and H3K27me1). This immunolabelling pattern resembles that of early developmental stages of Arabidopsis nuclei, with less pronounced heterochromatin chromocenters and heterochromatic marks weakly dispersed throughout the nucleus.

[Biocompatibility of JJ magnetic retainer metal materials]

OBJECTIVE

The purpose of this study was to evaluate the biocompatibility of new JJ-magnetic retainer metal materials.

METHODS

Preliminary biocompatible tests of the metal materials were performed depending on ISO 10.993-12 standard. They were cytotoxicity test, hemolysis test, acute systemic toxicity test, sensitization test and Ames test.

RESULTS

The cytotoxicity of the metal material was grade I. The hemolysis rate was 0.45%. There was no abnormal sensitization and irritation actions in the experimental group. The metal had no action of mutagenesis and carcinogenesis.

CONCLUSION

The JJ-magnetic retainer metal material showed excellent biocompatibility on the preliminary tests. It would be a good material in the way of biological safety.