De novo lipogenesis and desaturation of fatty acids during adipogenesis in bovine adipose-derived mesenchymal stem cells.

Adipose-derived mesenchymal stem cells (ADSCs) are useful cell model to study adipogenesis and energy metabolism. However, the biological characteristics of bovine ADSCs (bADSCs) remain unclear. This study aimed to isolate and identify bADSCs and further investigate fatty acid (FA)-related gene expression and composition of FAs during adipogenesis. The growth curve showed the bADSCs of P5 cells had rapid proliferation superior to P10-P50. The colony formation assay showed colony number of P5 cells was higher than that of P50 cells (51.67 ± 3.06 vs 35.67 ± 6.43, P < 0.05). The immunofluorescence showed that bADSCs were positive for CD13, CD44, CD49d, CD90, CD105, and Vimentin while negative for CD34. The multipotential towards adipocyte, osteocyte, and chondrocyte was confirmed by specific histological staining and lineage gene expression. During adipogenic induction, the genes related to lipogenesis and lipolysis were assessed by real-time PCR and the FA composition was detected by GC-MS. Expression of lipogenesis-related genes showed coordinated regulation as peaking on day 7 and declining until induction ended, including PPARγ, SREBP1, ACC1, FAS, ELOVL6, SCD1, and FABP4. FA deposition-related genes (DGAT1 and ACAT1) increased until day 14. Lipolysis genes (CPT-1A, VLCAD, and ACO) showed a variant expression pattern. The profile of FAs showed that proportion of the FAs (C4-C15, ≥ C22) increased, but proportion of long-chain fatty acids (C16-C20) reduced after induction. And saturated FAs (SFA) decreased while monounsaturated FAs (MUFA) and polyunsaturated FAs (PUFA) increased during adipogenesis. These data suggest that bADSCs possess the characteristics of mesenchymal stem cells and have active de novo lipogenesis (DNL) and desaturation of FAs during adipogenesis.