Effects of Ectopic Expression of Transcription Factors on Adipogenic Transdifferentiation in Bovine Myoblasts

Abstract

The present study was conducted to investigate whether myoblasts can be transdifferentiated into adipocytes by ectopic expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer-binding protein-α (C/EBPα), sterol regulatory element binding protein-1c (SREBP1c), and Krueppel-like factor 5 (KLF5), in primary bovine satellite cells. Transcription factors were transiently transfected into primary bovine myoblasts, and the cells were cultured with adipogenic differentiation medium for 2 days and then cultured on growth medium for an additional 8 days. Ectopic expression of PPARγ or C/EBPα alone was insufficient to induce adipogenesis in myoblasts. However, overexpression of both PPARγ and C/EBPα in myoblasts was able to induce adipogenic transdifferentiation as indicated by the appearance of mature adipocytes, the induction of adipogenic gene expressions, and the suppression of myogenic gene expressions. In addition, KLF5 and PPARγ co-transfected bovine myoblasts were converted to adipocytes but not in cells transfected with only KLF5 expression vector. Overexpression of SREBP1c alone was sufficient to induce transdifferentiation from myoblasts into adipocytes. These results demonstrate that primary bovine satellite cells can be transdifferentiated into adipocytes either by single ectopic expression or combined expression of adipogenic transcription factors in a culture system.