Albumin expression is required for adipocyte differentiation of 3T3-L1 cells.
We have previously demonstrated that albumin is directly involved in the formation of cytoplasmic lipid droplets in pancreatic stellate cells and may act as a downstream effector of adipogenic transcription factors, PPAR-gamma and C/EBP-alpha. Here, we investigated the role of albumin in adipocyte differentiation using 3T3-L1 cells. Albumin expression was significantly increased at later stages of adipocyte differentiation, which was accompanied with increased C/EBP-beta binding to albumin promoter. Suppression of albumin expression using short-hairpin RNA (shRNA) during differentiation led to a considerable reduction in lipid droplet formation, whereas albumin overexpression was stimulatory. Furthermore, point mutation in its fatty acid-binding sites inhibited lipid droplet formation. Consistent with these in vitro finding, Nagase analbuminemic rats displayed reduced fat accumulation. Therefore, our findings suggest that albumin may play a distinct role in adipocyte differentiation by promoting lipid accumulation.
Laboratory of Cellular Oncology, Korea University Graduate School of Medicine, Ansan, Gyeonggi do 425-707, Republic of Korea.
Wonbaek
W
Yoo
Jaeseob
J
Lee
Sangeun
S
Park
Young-Sik
YS
Kim
Chaeseung
C
Lim
Eulsik
E
Yoon
Gangmin
G
Hur
Junseo
J
Oh
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000502:physiology*; D050156:Adipogenesis; D000418:Albumins / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001665:Binding Sites; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D005227:Fatty Acids; D005786:Gene Expression Regulation; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D017354:Point Mutation; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley
D000418:Albumins; D022782:CCAAT-Enhancer-Binding Protein-beta; C545013:Cebpb protein, mouse; D005227:Fatty Acids; D034741:RNA, Small Interfering