ABSTRACT
Objective:To explore the role and mechanism of nuclear receptor subfamily 4 group A member 1 ( NR4A1) in suppressing cisplatin nephrotoxicity. Methods:The expression of NR4A1 gene in renal cell subpopulations was analyzed using the "Tabula-muris" single cell transcriptome sequencing database. NR4A1 gene was over-expressed by lentivirus infection in HK-2 cell line and primary renal proximal tubular epithelial cells. Cell counting kit-8 was used to detect the cytotoxicity of cisplatin. The cell death ratio was analyzed using propidium iodide (PI) staining by flow cytometry. The expression of NR4A1 and nuclear factor erythroid 2-related factor 2 ( NRF2) was detected by real-time fluorescent quantitative PCR and Western blotting. Ferroptosis was analyzed by detecting the contents of malondialdehyde (MDA), oxidized glutathione (GSSG) and lipid reactive oxygen species (ROS). Results:The single cell transcriptome sequencing database showed that NR4A1 gene was the lowest expression in renal proximal tubular epithelial cell subsets. Cisplatin (50 μmol/L or 100 μmol/L) could significantly induce MDA, GSSG and lipid ROS production in renal proximal tubular epithelial cells (all P<0.01), and higher cisplatin concentration accompanied with a more increase of MDA, GSSG and lipid ROS. Compared with the control HK-2 cells, the lipid ROS content and iron ion content of HK-2 cells over-expressing NR4A1 were significantly lower (all P<0.01), and the over-expression of NR4A1 inhibited cisplatin-induced cytotoxicity and ferroptosis in renal proximal tubular epithelial cells. Mechanistically, NR4A1 up-regulated the expression of anti-ferroptosis gene NRF2 in proximal renal tubular epithelial cells ( P<0.01). Furthermore, single cell data analysis showed that, similar to the expression of NR4A1 in renal tissue subsets, NRF2 was also the lowest in renal proximal tubular epithelial cells. Conclusions:Cisplatin can induce ferroptosis of renal proximal tubular epithelial cells in a dose-dependent manner. NR4A1 can inhibit cisplatin-induced ferroptosis by up-regulating NRF2 in renal proximal tubular epithelial cells, thereby alleviating the cytotoxicity of cisplatin.
ABSTRACT
Objective:To investigate the relationship between low vitamin D levels and the risk of Graves' disease.Methods:Computer was used to search PubMed, EMbase, China National Knowledge Infrastructure (CNKI), Wanfang Database (Wanfang Data) and China Biomedical Database (CBM). Relevant Chinese and English literatures were collected, including literatures of vitamin D, Graves' disease and autoimmune thyroid disease from the earliest publication time of the literature in the database to September 2019. Statistical software Stata 12.0 was used for Meta-analysis of the data. Heterogeneity test was conducted on the literature that met the inclusion criteria. According to the results, a random-effect model fixed-effect model was selected for comprehensive quantitative analysis. Standardized mean difference ( SMD) and 95% confidence interval ( CI) were calculated, and Egger's test was used to evaluate publication bias and sensitivity analysis. Results:A total of 29 literatures were included in the study, covering 2 281 patients with Graves' disease and 4 200 control population. Meta-analysis results showed: after the data were combined using a random-effects model, vitamin D levels in patients with Graves' disease were significantly lower than that in the control population ( SMD = - 0.90, 95% CI: - 1.14, - 0.66, P < 0.01﹚; heterogeneity analysis and Meta-regression analysis showed that the four factors of national development degree, geographical location, indicator measurement method and whether Graves' disease was primary were not the main source of heterogeneity. However, in developing countries or Asian, the vitamin D levels of patients with Graves' disease were significantly lower than that of the control population ( P < 0.01). In developed countries or Europe, the difference was not statistically significant ( P > 0.05). Sensitivity analysis and publication bias analysis showed that the results of this study had certain stability and reliability. Conclusion:Low vitamin D levels may increase the risk of Graves' disease.