gw9662 and alpinetin

Alpinetin is a flavonoid which exerts antibacterial and anti-inflammatory functions. In order to prove that the induced methylation is an important mechanism for alpinetin in regulating the expression of inflammatory factor Interleukin-6 (IL-6), we detected the dinucleotide methylation status of CpG islands in the IL-6 promoter region and IL-6 level after treatment of RAW246.7 murine macrophages with alpinetin.. After RAW246.7 murine macrophages were treated with alpinetin, alpinetin + GW9662 (the peroxisome proliferator-activated receptor (PPAR) antagonist), and alpinetin + DNA methyltransferase 3 alpha (DNMT3A) siRNA for 96 hr, CpG islands were analyzed using time-of-flight mass spectrophotometry (TOF-MS) and bisulfite sequencing polymerase chain reaction (BSP). Dinucleotide methylation status of the CpG islands in the IL-6 promoter region was analyzed by methylation-specific Polymerase Chain Reaction (PCR). IL-6 level was detected using the enzyme-linked immunosorbent assay (ELISA) method. Pearson's correlation analysis was conducted to test for potential correlation between the methylation status of CpG islands in the IL-6 promoter region and IL-6 level in RAW 246.7 cells.. Alpinetin promoted dinucleotide methylation status of two CpG islands in the IL-6 promoter region stretching 500-2500 bp upstream of the transcriptional start site (TSS) (p < .05). This promoting effect was more significant for the CpG island stretching 500-1500 bp long. The methylation ratio of dinucleotide at this position was significantly inversely correlated with the level of IL-6 (p < .05). PPAR antagonist GW9662 and interference of DNMT3A could reverse both the alpinetin-induced methylation and inhibitory effects on IL-6 expression.. Alpinetin could induce dinucleotide methylation status of CpG islands in the IL-6 promoter region by activating methyltransferase, thus inhibiting IL-6 expression in murine macrophages.

Topics: 5-Methylcytosine; Anilides; Animals; Anti-Inflammatory Agents; CpG Islands; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; DNA Methyltransferase 3A; Flavanones; Interleukin-6; Mice; Peroxisome Proliferator-Activated Receptors; Promoter Regions, Genetic; RAW 264.7 Cells

Objective To screen the nucleus located-methyltransferase in murine macrophages (RAW246.7 cells) after peroxisome proliferator-activated receptors (PPAR) is activated by alpinetin so as to prove the epigenetic modification effect of alpinetin. Methods RAW246.7 cells were divided into control group, alpinetin group (final concentrations including 100, 200, 500, 1000 μg/mL) and 1000 μg/mL alpinetin combined with 0.1 mmol/mL GW9662 group. Firstly, bioinformatics database String was searched for the methyltransferases which might interact with PPAR. Then co-immunoprecipitation was used to screen the specific nucleus-located methyltransferase interacting with PPAR. Finally, the expressions of the related methyltransferases were validated by fluorescent quantitative PCR. Results Co-immunoprecipitation proved that EZH2, DNMT3α and TDG were the specific methyltransferases which interacted with the activated PPAR in the nucleus when induced by a certain concentration of alpinetin, which was basically consistent with the search result of the String database. No methyltransferase was found to interact with PPAR if GW9662 was added. Furthermore, only by a high concentration of alpinetin (1 000 μg/mL), could the synthesis of TDG mRNA be promoted, yet the synthesis of DNMT3α and EZH2 were not influenced. Conclusion Alpinetin, the PPAR activator, could promote the synthesis and interaction of specific methyltransferases with PPAR in the nucleus, which indicates that methylation modification on histone or cytosine may be the interpretation for the effect of gene expression regulation caused by alpinetin.

Topics: Anilides; Animals; Cell Nucleus; Cells, Cultured; Computational Biology; Flavanones; Methyltransferases; Mice; Peroxisome Proliferator-Activated Receptors