Emodin with PPARgamma ligand-binding activity promotes adipocyte differentiation and increases glucose uptake in 3T3-Ll cells.
Emodin, one of the main active components in the root and rhizome of Rheum palmatum L, promoted the conversion of 3T3-L1 fibroblasts to adipocytes, as evidenced by increased glycerol-3-phosphate dehydrogenase (GPDH) activity and the expression of adipocyte aP2 mRNA, as well as accelerated triacylglycerol (TG) accumulation, which was associated with increased mRNA expression levels of both C/EBPalpha and PPARgamma2. By using surface plasmon resonance (SPR) experiment, it was showed that emodin exhibited a very high binding affinity to PPARgamma. In differentiated 3T3-L1 adipocytes, emodin induced a time- and dose-dependent increase in glucose uptake as well as GLUT1 and GLUT4 mRNA expression, and the rate of uptake was partly abrogated by wortmannin (phosphoinositide 3-kinase inhibitor). Meanwhile, insulin-stimulated glucose uptake was increased significantly after treatment with low doses of emodin, and the degree of potentiation was decreased thereafter in response to increasing concentrations. Furthermore, 50 microM emodin profoundly inhibited insulin-stimulated glucose uptake by 25%. These data suggest a new role for emodin as a PPARgamma agonist in 3T3-L1 cells. Besides, it is possible that emodin may also possess other properties contribute to glucose utilization in the adipocytes.
Yang
Ying
Y
Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, 197 Ruijin Road II, Shanghai 200025, China.
Shang
Wenbin
W
Zhou
Libin
L
Jiang
Boren
B
Jin
Hua
H
Chen
Mingdao
M
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002454:Cell Differentiation; D004305:Dose-Response Relationship, Drug; D004642:Emodin / Q000008:administration & dosage*; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism*; D005947:Glucose / Q000493:pharmacokinetics*; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D008657:Metabolic Clearance Rate; D051379:Mice; D047495:PPAR gamma / Q000378:metabolism*; D011485:Protein Binding
D004791:Enzyme Inhibitors; D047495:PPAR gamma; D005993:Glycerolphosphate Dehydrogenase; D005947:Glucose; D004642:Emodin