[Alpinetin promotes the binding of PPAR and methyltransferase]

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.