Differential expression of signal transducers and activators of transcription during human adipogenesis

Signal Transducers and Activators of Transcription (STATs) display unique expression patterns upon induction of differentiation of murine 3T3-L1 preadipocytes into adipocytes. During differentiation, expression of STAT1 and STAT5 increase, while STAT3 and STAT6 remain relatively unchanged. Here, we determined whether human subcutaneous preadipocytes expressed STATs and if the pattern of expression changed during adipogenesis. We found by Western blot analysis that freshly isolated preadipocytes expressed STAT1, STAT3, STAT5, and STAT6, but not STAT2 and STAT4. Induction of preadipocyte differentiation with 1-methyl-3-isobutylxanthine, dexamethasone, insulin, and BRL49653 decreased expression of STAT1, and increased expression of STAT3 and STAT5. STAT6 expression did not change during adipogenesis. Changes in expression of CCAAT/enhancer binding protein beta (C/EBPbeta), C/EBPdelta, C/EBPalpha, and peroxisome proliferator-activated receptor gamma were similar to murine cell lines. These results suggest that unlike the traditional adipogenic transcription factors, unique differences exist in STAT expression patterns between murine and human adipose cells.