title: Prolonged induction activates Cebpα independent adipogenesis in NIH/3T3 cells.
abstract: BACKGROUND
  3T3-L1 cells are widely used to study adipogenesis and insulin response. Their adipogenic potential decreases with time in the culture. Expressing exogenous genes in 3T3-L1 cells can be challenging. This work tries to establish and characterize an alternative model of cultured adipocytes that is easier to work with than the 3T3-L1 cells.
  
  
  RESULTS
  INDUCED CELLS WERE IDENTIFIED AS ADIPOCYTES BASED ON THE FOLLOWING THREE CHARACTERISTICS: (1) Accumulation of triglyceride droplets as demonstrated by oil red O stain. (2) Transport rate of 2-deoxyglucose increased after insulin stimulation. (3) Expression of fat specific genes such as Fabp4 (aP2), Slc2a4 (Glut4) and Pparg (PPARγ). Among the cell lines induced under different conditions in this study, only NIH/3T3 cells differentiated into adipocytes after prolonged incubation in 3T3-L1 induction medium containing 20% instead of 10% fetal bovine serum. Rosiglitazone added to the induction medium shortened the incubation period from 14 to 7 days. The PI3K/AKT pathway showed similar changes upon insulin stimulation in these two adipocytes. C/EBPα mRNA was barely detectable in NIH/3T3 adipocytes. NIH/3T3 adipocytes induced in the presence of rosiglitazone showed higher 2-deoxyglucose transport rate after insulin stimulation, expressed less Agt (angiotensinogen) and more PPARγ. Knockdown of C/EBPα using shRNA blocked 3T3-L1 but not NIH/3T3 cell differentiation. Mouse adipose tissues from various anatomical locations showed comparable levels of C/EBPα mRNA.
  
  
  CONCLUSIONS
  NIH/3T3 cells were capable of differentiating into adipocytes without genetic engineering. They were an adipocyte model that did not require the reciprocal activation between C/EBPα and PPARγ to differentiate. Future studies in the C/EBPα independent pathways leading to insulin responsiveness may reveal new targets to diabetes treatment.
authors: Graduate Institute of Molecular and Cell Biology, Tzu Chi University, Hualien, Taiwan.
authors: Hsiao-Yun
authors: HY
authors: Shao
authors: Hsue-Yin
authors: HY
authors: Hsu
authors: Kuan-Sju
authors: KS
authors: Wu
authors: Siow-Wey
authors: SW
authors: Hee
authors: Lee-Ming
authors: LM
authors: Chuang
authors: Jih-I
authors: JI
authors: Yeh
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects* / Q000235:genetics; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology*; D003847:Deoxyglucose / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077154:Rosiglitazone; D044967:Serum; D045162:Thiazolidinediones / Q000494:pharmacology; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D003470:Culture Media; C493411:Fabp4 protein, mouse; D050556:Fatty Acid-Binding Proteins; D007004:Hypoglycemic Agents; D007328:Insulin; D047495:PPAR gamma; D045162:Thiazolidinediones; D014280:Triglycerides; D000077154:Rosiglitazone; D003847:Deoxyglucose