Ectopic expression of porcine peroxisome‐proliferator‐activated receptor delta regulates adipogenesis in myoblasts

It is well known that peroxisome‐proliferator‐activated receptor γ (PPAR γ) plays a critical role in regulating adipogenesis. In rodents, PPAR δ is expressed before PPAR γ during adipocyte differentiation. Thus, the interaction between PPAR δ and PPAR γ during adipogenesis needs to be elucidated. The current experiment was designed to study the interaction of porcine PPAR δ and PPAR γ in mouse myoblast cells. Inhibition of myogenesis was observed in myoblasts expressing porcine PPAR δ, similar to myoblast expressing PPAR γ. Treatment of myoblasts expressing PPAR δ with ligands for both PPAR δ and γ enhanced lipogenesis to a greater extent than treatment with a PPAR γ ligand alone. The ability to transdifferentiate myoblasts into adipocytes was decreased in myoblasts co‐expressing PPAR δ with either wild‐type or mutated PPAR γ (serine 112 was mutated to alanine) compared to myoblasts expressing either type of PPAR □ alone. Adipose transdifferentiation in myoblasts co‐expressing PPAR δ and mutated PPAR γ was greater than in myoblasts co‐expressing PPAR δ and wild‐type PPAR γ. Our results suggest that PPAR δ has two different roles in regulating adipogenesis, ie., suppression of myogenesis to enhance transdifferentiation of myoblasts into adipocytes and interaction with PPAR γ to modify adipogenesis. Therefore, PPAR δ may have a significant role in adipogenesis.