Epigallocatechin gallate targets FTO and inhibits adipogenesis in an mRNA m6A-YTHDF2-dependent manner.

Abstract

BACKGROUND/OBJECTIVE:

N6-methyladenosine (m6A) modification of mRNA plays a role in regulating adipogenesis. However, its underlying mechanism remains largely unknown. Epigallocatechin gallate (EGCG), the most abundant catechin in green tea, plays a critical role in anti-obesity and anti-adipogenesis.

METHODS:

High-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS) was performed to determine the m6A levels in 3T3-L1 preadipocytes. The effects of EGCG on the m6A levels in specific genes were determined by methylated RNA immunoprecipitation coupled with quantitative real-time PCR (meRIP-qPCR). Several adipogenesis makers and cell cycle genes were analyzed by quantitative real-time PCR (qPCR) and western blotting. Lipid accumulation was evaluated by oil red O staining. All measurements were performed at least for three times.

RESULTS:

Here we showed that EGCG inhibited adipogenesis by blocking the mitotic clonal expansion (MCE) at the early stage of adipocyte differentiation. Exposing 3T3-L1 cells to EGCG reduced the expression of fat mass and obesity-associated (FTO) protein, an m6A demethylase, which led to increased overall levels of RNA m6A methylation. Cyclin A2 (CCNA2) and cyclin dependent kinase 2 (CDK2) play vital roles in MCE. The m6A levels of CCNA2 and CDK2 mRNA were dramatically enhanced by EGCG. Interestingly, EGCG increased the expression of YTH N6-methyladenosine RNA binding protein 2 (YTHDF2), which recognized and decayed methylated mRNAs, resulting in decreased protein levels of CCNA2 and CDK2. As a result, MCE was blocked and adipogenesis was inhibited. FTO overexpression and YTHDF2 knockdown in 3T3-L1 cells significantly increased CCNA2 and CDK2 protein levels and ameliorated the EGCG-induced adipogenesis inhibition. Thus, m6A-dependent CCNA2 and CDK2 expressions mediated by FTO and YTHDF2 contributed to EGCG-induced adipogenesis inhibition.

CONCLUSION:

Our findings provide mechanistic insights into how m6A is involved in the EGCG regulation of adipogenesis and shed light on its anti-obesity effect.

• Authors: Ruifan Wu, Yongxi Yao, Qin Jiang, Min Cai, Qing Liu, Yizhen Wang, Xinxia Wang
• Journal: International journal of obesity (2005) (Int J Obes (Lond)) Vol. 42 Issue 7 Pg. 1378-1388 (07 2018) ISSN: 1476-5497 [Electronic] England
• PMID: 29795461 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Obesity Agents
• RNA, Messenger
• RNA-Binding Proteins
• Tea
• YTHDF2 protein, mouse
• Catechin
• epigallocatechin gallate
• FTO protein, mouse
• Alpha-Ketoglutarate-Dependent Dioxygenase FTO

Topics

• 3T3-L1 Cells (cytology)
• Adipocytes (cytology, drug effects)
• Adipogenesis (drug effects)
• Alpha-Ketoglutarate-Dependent Dioxygenase FTO (deficiency, metabolism)
• Animals
• Anti-Obesity Agents (pharmacology)
• Catechin (analogs & derivatives, pharmacology)
• Disease Models, Animal
• Mice
• RNA, Messenger (chemistry, genetics, metabolism)
• RNA-Binding Proteins (metabolism)
• Tea (chemistry)