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Objective To investigate the effect of trichostatin A (TSA) and 5-azacitidine (5-AzaC) on pancreatic β-cells impaired by cytokine,via measuring the proliferation,apoptosis,and function of pancreatic β-cells.Methods RIN-m5f was impaired by interleukin-1β and interferon-γin vitro,and treated with TSA and 5-AzaC.Experiment groups included blank control group,cytokine induction group,0.05/0.10 μmoL/L TSA group,0.63/1.25 μmoL/L 5-AzaC group,and0.10 μmol/L TSA plus 1.25 μmol/L 5-AzaC group.The viability of RIN-m5f cells was detected by MTT assay.Apoptotic rate was determined by Annexin V-fluorescein isothiocyanate (FITC) /propidium iodide flow cytometry.Insulin secretion was measured by enzyme-linked immunosorbent assay.Results The viability of RIN-m5f cells in 0.05/0.10 μmoL/L TSA group,0.63/1.25 μmol/L 5-AzaC group,and 5-AzaC plus TSA group was 70.1％/79.2 ％,67.3 ％/82.9 ％,and 89.1％ respectively,being higher than that in the cytokine group (33.9％,P＜0.05) ; the apoptosis rate was 10.3％/10.5％,7.9％/9.6％,and 8.2％,being lower than that in the cytokine group (16.6％,P＜0.05) ; the capacity of glucose-stimulated insulin secretion of all the treated groups was higher than that in the cytokine group (P＜0.05).Conclusion TSA and 5-AzaC might promote the proliferation of pancreatic β-cells impaired by cytokines,inhibit its apoptosis and recover its insulin secretion.
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OBJECTIVE@#To construct a special luciferase reporter to detect DNA methylation regulatory activity in FCER1G gene promoter regulatory element.@*METHODS@#We constructed special full and mock methylated FCER1G gene promoter regulatory luciferase reporters by patch-methylation, and detected DNA methylation regulatory activity by comparing the luciferase activity of full-methylated luciferase reporters with mock-methylated reporters.@*RESULTS@#We successfully constructed the full and mock methylated FCER1G gene promoter regulatory luciferase reporters. The ratio of luciferase activity between the full methylated and the mock methylated was (0.36±0.07):1 (P<0.001).@*CONCLUSION@#FCER1G promoter activity is methylation-sensitive and is regulated by DNA methylation.
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Humans , Base Sequence , DNA Methylation , Gene Expression Regulation , Genes, Reporter , Luciferases , Genetics , Molecular Sequence Data , Promoter Regions, Genetic , Genetics , Receptors, IgE , Genetics , MetabolismABSTRACT
Objective To estimate the influence of 1,25(OH)2D3 on the proliferative ability of and methylation levels of genomic DNA and proliferation-associated gene promoter in human HaCaT keratinocytes.Methods Some cultured HaCaT cells were treated with 1,25 (OH)2D3 of 10-6,10-7 and 10-8 mol/L for 24 hours,then,methyl thiazolyl tetrazolium (MTT) assay was carried out to evaluate the proliferative activity of cells,and a global DNA methylation quantification kit was used to determine the global DNA methylation level.Real-time PCR was conducted to quantify the mRNA expression of DNA methyl transferases (DNMTs) and methyl-DNA binding domain (MBD) proteins,and methylation-specific PCR (MS-PCR) to evaluate the methylation status of promoter region in the programmed cell death 5 (PDCD5) and tissue inhibitor of metalloproteinase 2 (TIMP2) genes,in HaCaT cells after 24-hour treatment with 1,25 (OH)2D3 of 10-6 mol/L.The HaCaT cells receiving no treatment served as the control.Results Compared with the untreated HaCaT cells,those treated with 1,25(OH)2D3 of 10-6 mol/L showed significantly down-regulated proliferative activity (0.152 ± 0.027 vs.0.290 ± 0.017,P ＜ 0.01),global DNA methylation level (0.187 ± 0.071 vs.0.316 ± 0.049,P ＜ 0.05),DNMT3a and DNMT3b mRNA expression levels (P ＜ 0.01 or 0.05),but markedly upregulated mRNA expression levels of MECP2,MBD2,PDCD5 and TIMP2 (P ＜ 0.01 or 0.05).Moreover,the DNA methylation levels within the promoter region of PDCD5 and TIMP2 genes were significantly lower in HaCaT cells treated with 1,25 (OH)2D3 of 10-6 mol/L than in the control cells (0.38 ± 0.135 vs.0.72 ± 0.121,0.46 ± 0.172 vs.0.68 ± 0.133,both P＜ 0.05).Conclusions 1,25(OH)2D3 may down-regulate the global genomic DNA methylation level of,and modulate the expression of DNA methylationmodifying genes in,HaCaT cells.Furthermore,1,25 (OH)2D3 can decrease the promoter methylation levels but induce the overexpression of PDCD5 and TIMP2 genes,and decelerate the proliferation of HaCaT cells.
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Objective:To explore the mechanisms by which DNA methylation regulates miR-126 and its host gene EGFL7 in CD4+T cells from patients with systemic lupus erythematosus (SLE). Methods:We analyzed the expression and the DNA methylation status within promoter region of EGFL7 and miR-126 by real-time qPCR and bisulifte genomic sequencing analysis. Results:miR-126 and EGFL7 mRNA expression was upregulated in CD4+T cells from SLE compared with that from healthy controls (P Conclusion:hTe upregulation of miR-126 and its host gene EGFL7 expression in CD4+T cells from SLE is associated with the hypomethylation of the EGFL7 promoter.
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OBJECTIVE@#To investigate the effect of total glucosides of peony (TGP) on expression and DNA methylation status of ITGAL gene (CD11a) in CD4(+) T cells from patients with systemic lupus erythematosus (SLE).@*METHODS@#CD4(+) T cells were isolated by positive selection using CD4 beads. CD4(+) T cells were treated by TGP at 0, 62.5, 312.5 and 1562.5 mg/L for 48 h. The MTT method was used to assess cell viability; mRNA expression level was measured by realtime-PCR; protein level of CD11a was measured by flow cytometric analysis; DNA methylation status was assayed by bisulfite sequencing.@*RESULTS@#No significant change in cell viability was found in CD4(+) T cells among the different concentration groups (P>0.05). Compared with control, the mRNA and protein levels of ITGAL were down-regulated significantly in SLE CD4(+) T cells treated with TGP (1562.5 mg/L) (P< 0.01). Furthermore, the extent of DNA methylation of ITGAL promoter was increased in TGP (1562.5 mg/L) treated CD4(+) T cells compared with control group (P<0.01).@*CONCLUSION@#TGP can repress CD11a gene expression through enhancing DNA methylation of ITGAL promoter in CD4(+) T cells from patients with SLE. This observation represents a preliminary step in understanding the mechanism of TGP in SLE therapy.