TGFβ3 regulates adipogenesis of bovine subcutaneous preadipocytes via typical Smad and atypical MAPK signaling pathways

Abstract

Background: Transforming growth factor β3 (TGFβ3) is a member of TGFβ superfamily. Studies have shown that TGFβ is involved in adipose tissue biology. Whether TGFβ3 is a crucial regulator in adipogenic differentiation of bovine preadipocytes remains unclear. The main objective of this study was to investigate the effect of TGFβ3 on the adipogenic differentiation of bovine preadipocytes as well as the underlying mechanisms.

Results: Primary subcutaneous preadipocytes derived from bovine subcutaneous adipose tissue were isolated and used as a cellular model. The results showed that TGFβ3 significantly promoted the proliferation of bovine preadipocytes and markedly decreased the lipid accumulation and expression levels of key adipogenic marker genes (PPARγ, c/EBPα, and FABP4) during adipocyte differentiation. In addition, TGFβ3 significantly increased the phosphorylation levels of Smad2, Smad3, JNK, and p38 in bovine preadipocytes, which could be eliminated by SB525334 (a TGFβRI inhibitor). Further studies showed that Smad3 and p38 mediated the inhibitory effect of TGFβ3 on differentiation, whereas Smad2 attenuated the anti-adipogenic effect of TGFβ3.

Conclusions: To sum up, our findings indicate that TGFβ3 is an important regulator of adipogenesis in bovine. TGFβ3 promotes the proliferation and regulates the differentiation of bovine preadipocytes through Smad2/3 and p38 signaling pathways.