Research Note: Potential usage of DF-1 cell line as a new cell model for avian adipogenesis.

Current research of avian adipogenesis has been dependent on primary preadipocytes culture due to the lack of commercially available immortal preadipocyte cell lines in avian species. In addition to primary stromal vascular cells, primary chicken embryonic fibroblasts (CEF) were suggested as new in vitro models for adipogenesis study, because CEF can be differentiated into adipocytes by a combination of fatty acids and insulin (FI), or all-trans retinoic acid (atRA) alone in the media containing chicken serum (CS). However, there are decreases in differentiation of primary cells due to diverse population of cell types and low adipogenic potential of cells after passages. In the present study, adipogenic differentiation of DF-1 cells, immortal fibroblasts derived from an embryonic chicken, was tested with 4 different medium; 10% fetal bovine serum (FBS), 10% CS, 10% CS with FI, and 10% CS with FI and atRA. Lipid droplets stained with Oil Red O were not shown in DF-1 cells under 10% FBS, appeared with very small sizes under 10% CS, significantly increased under 10% CS with FI, and most significantly accumulated under 10% CS with FI and atRA. In addition, expressions of markers for adipogenesis (Znf423, C/ebpβ, Pparγ, and Fabp4), fatty acid uptake (CD36), triglyceride synthesis (Gpd1, Dgat2), and lipid droplet stabilization (Plin1) were significantly upregulated by supplementation of 10% CS with FI and atRA. Morphological evidence for formation of lipid droplets and dramatic induction of adipogenic marker genes support the adipogenic potential of DF-1 cells, offering DF-1 cells as a new cell model to investigate various research studies involving avian adipogenesis.