Uptake of fluorescent fatty acids by erythroleukemia cells. Effect of differentiation.

The uptake of a fluorescent derivative of a fatty acid (FDFA), 12-(1-pyrene) dodecanoic acid (P12) by murine erythroleukemia (MEL) cells was studied. Because of the intense fluorescence of the pyrene ring, the association of P12 with intact cells could be analysed using a fluorescence microscope or a fluorescence-activated cell sorter (FACS), and the incorporation of P12 into cellular lipids could be quantified, following their extraction in a spectrofluorimeter. These procedures indicated that P12 uptake and intracellular utilization are reduced, following induction of erythrodifferentiation by dimethylsulfoxide (DMSO) or hexamethylene-bis-acetamide (HMBA). The differences in the fluorescence observed following exposure to P12 permitted us to separate a mixture of differentiated and undifferentiated cells into two distinct cell subpopulations; the high fluorescence population consisted mainly of undifferentiated cells, and the low one of differentiated cells. The results of this study suggest that fluorescent fatty acids are useful for distinguishing between and sorting cells at different stages of differentiation.