Co-culture of Bovine Muscle Satellite Cells with Preadipocytes Increases PPARγ and C/EBPβ Gene Expression in Differentiated Myoblasts and Increases GPR43 Gene Expression in Adipocytes

Abstract

We hypothesized that preadipocyte differentiation would be depressed by differentiating myoblasts, whereas preadipocytes would promote adipogenic gene expression in myoblasts in a co-culture system. We also determined the effects of arginine, a biological precursor of nitric oxide, and/or trans-10, cis-12 conjugated linoleic acid (CIA) on adipogenic gene expression during differentiation of bovine preadipocytes and myoblasts. Bovine semimembranosus satellite cells (BSC) and subcutaneous preadipocytes were isolated from crossbred steers and cultured with 10% fetal bovine serum (FBS)/Dulbecco's modified Eagle medium (DMEM) and 1% antibiotics during the 3-day proliferation period. After proliferation, BSC and preadipocytes were treated for 3 days with 3% horse serum/DMEM and 5% FBS/DMEM with antibiotics, respectively. Media also contained 100 mu M oleic acid, 10 mu g/ml insulin, 1 mu g/ml pioglitazone and 1 mu g/ml dexamethasone. Subsequently, the differentiating myoblasts and adipocytes were cultured in their respective media with 5 mM arginine and/or 40 mu M trans-10, cis-12 CIA for 4 days. Finally, myoblasts and adipocytes were single- or co-cultured for 2 h singly or in combination. Arginine stimulated SCD gene expression, whereas CIA depressed SCD gene expression in adipocytes and myoblasts (P=.002). Co-culture of adipocytes and myoblasts elicited an increase in C/EBP beta and PPAR gamma gene expression in differentiated myoblasts (P <=.01) and an increase in GPR43 gene expression in adipocytes (P=.01). Expression of AMPK alpha and CPT1 beta was unaffected by co-culture, although SCD gene expression tended (P=.12) to be depressed by co-culture. These experiments demonstrated that co-culture of adipocytes with myoblasts increased adipogenic gene expression in the myoblastic cells.