301. Octanoate attenuates adipogenesis in 3T3-L1 preadipocytes.
- Author
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Han J, Farmer SR, Kirkland JL, Corkey BE, Yoon R, Pirtskhalava T, Ido Y, and Guo W
- Subjects
- 3T3 Cells, Adipocytes cytology, Adipose Tissue, Animals, Blotting, Western, CCAAT-Enhancer-Binding Proteins metabolism, Calcium-Binding Proteins, Carrier Proteins metabolism, Cell Differentiation physiology, DNA-Binding Proteins metabolism, Fatty Acid-Binding Protein 7, Fatty Acid-Binding Proteins, Glycerolphosphate Dehydrogenase metabolism, Intercellular Signaling Peptides and Proteins, Leptin metabolism, Lipid Metabolism, Mice, RNA, Messenger analysis, Receptors, Cytoplasmic and Nuclear drug effects, Sterol Regulatory Element Binding Protein 1, Transcription Factor CHOP, Transcription Factors drug effects, Adipocytes metabolism, Caprylates pharmacology, Cell Differentiation drug effects, Growth Inhibitors metabolism, Membrane Proteins metabolism, Neoplasm Proteins, Nerve Tissue Proteins, Receptors, Cytoplasmic and Nuclear metabolism, Repressor Proteins metabolism, Transcription Factors metabolism
- Abstract
Preadipocytes exposed to octanoate accumulate less lipid than cells exposed to long-chain fatty acids. This effect of octanoate involves significant attenuation of expression of key adipogenic transcription factors, including peroxisome proliferator-activated receptor (PPAR)gamma, steroid regulatory binding element protein (SREBP)-1c and CCAAT element binding protein (C/EBPalpha) at both the mRNA and protein levels. Expression of differentiation markers, including adipocyte fatty acid binding protein (ALBP), glycerol-3-phosphate dehydrogenase (GPDH) and leptin, was also significantly diminished by octanoate. However, octanoate did not prevent the decrease in preadipocyte factor-1 (Pref-1) expression that occurs during adipogenesis, nor did it inhibit the early induction of C/EBPbeta,delta. Treatment with synthetic PPARgamma ligands partially offset the inhibitory effect of octanoate on differentiation. Ectopic expression of PPARgamma2 in 3T3-L1 cells partially restored lipid accretion and GPDH activity in octanoate-treated cells. Adding octanoate together with troglitazone attenuated the effects of troglitazone on adipocyte differentiation in both normal 3T3-L1 cells and engineered 3T3-L1 cells that expressed ectopic PPARgamma2, implying that octanoate might compete against troglitazone for its binding to PPARgamma. These results suggest that octanoate may block adipogenesis at least in part by its influence on the expression/activation of PPARgamma.
- Published
- 2002
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