Mammary epithelial cell subpopulations from control and ovariectomized mice

To study the effect of pregnancy on mouse mammary epithelial subpopulations, epthelial cells derived from control or ovariectomized adult mice were isolated using fluorescence-activated cell sorting. After elimination of haematopoietic and endothelial cells, two distinct epithelial subpopulations were sorted using antibodies against CD29 and CD24. Based on the immunohistochemical phenotype, and in vivo and in vitro functional assays, these subpopulations were identified as mammary stem cell enriched (CD29hiCD24+) and luminal (CD29loCD24+) respectively (ref: Shackleton et al, Nature 2006). Microarray profiling was used to compare gene expression profiles of the two subpopulations isolated from ovariectomized and control mice. For each of two biological replicates, 6 FVB/NJ mice were ovariectomized at 8 weeks of age. 4 weeks after ovariectomy (Ovx) mammary gland from control or Ovx animals were collected and digested to obtain a single cell suspension. CD45-CD31-TER119- cells were then sorted based on the expression of cell surface markers CD24 and CD29. Similarly for two pools of control mice. There were also 4 technical replicates, to make 12 BeadChips in total.