A simple method to sort ESC-derived adipocytes.

Because of the increasing incidence of worldwide obesity, cell culture models which enable the study of adipose tissue development are of particular importance. The murine embryonic stem cell (ESC) line CGR8 differentiates into adipocytes with a differentiation efficiency of up to 15%. A critical step for the analysis of stem cell-derived adipogenesis is the reliable separation of adipocytes. Here we report on how to (i) gently separate the cells of embryoid bodies (EBs) and (ii) identify and sort adipocytes from the rest of the heterogeneous cell mixture. Up to the present, no adipocyte specific surface marker is known for fluorescence activated cell sorting (FACS). After separation we employed two independently existing FACS methods for adipocyte cell sorting. These methods are based on Nile red staining and granularity. For stem cell-derived adipocytes only the combination of both methods led to a reliable, efficient, and highly reproducible FACS analysis, as shown by the presence and absence of adipocyte specific markers in positively and negatively sorted cells.