title: (-)-Epigallocatechin gallate suppresses adipocyte differentiation through the MEK/ERK and PI3K/Akt pathways.
abstract: EGCG [(-)-epigallocatechin gallate], tea catechin, is one of the compounds that has been reported to act against obesity and diabetes. To determine the effect of EGCG on adipocyte differentiation, we treated 3T3-L1 preadipocytes with different catechins. Oil Red O staining showed significantly reduced intracellular lipid accumulation, especially with EGCG. Cell cycle analysis showed that EGCG inhibited cell proliferation by disturbing the cell cycle during the clonal expansion of 3T3-L1. RT-PCR (real-time PCR) demonstrated that EGCG noticeably reduced mRNA expression of PPARγ (peroxisome proliferator-activated receptor γ), C/EBPα (CCAAT/enhancer-binding protein α) and FoxO1 (forkhead box class O1). EGCG also caused a significant decrease in the transcription of FoxO1 - the forkhead transcription factor class O1 involved in adipocyte differentiation - via the PI3K (phosphoinositide 3-kinase)/Akt and MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] pathways. These results suggest that EGCG suppresses the clonal expansion of adipocytes by inactivating FoxO1 via insulin signalling and stress-dependent MAPK pathways.
authors: Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan.
authors: Hyojung
authors: H
authors: Kim
authors: Kazuichi
authors: K
authors: Sakamoto
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016196:S Phase; D015398:Signal Transduction / Q000187:drug effects*; D014158:Transcription, Genetic
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; C467200:Foxo1 protein, mouse; D007004:Hypoglycemic Agents; D047495:PPAR gamma; D002392:Catechin; C045651:epigallocatechin gallate; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases