Gene expression profiles of normal mouse mammary cell subpopulations FACS sorted based on expression of biomarkers

To delineate epithelial subpopulations in mouse mammary tissue, hematopoietic and endothelial cells were depleted from freshly isolated cell suspensions derived from mammary glands using fluorescence-activated cell sorting. The resultant Lin- population was fractionated into four distinct subpopulations using antibodies against CD29, CD24 and CD61. Based on the immunohistochemical phenotype, and in vivo and in vitro functional assays, these subpopulations were identified as fibroblast-containing stromal (CD29loCD24-), mammary stem cell (MaSC)-enriched (CD29hiCD24+CD61+), luminal progenitor (CD29loCD24+CD61+), and mature luminal (CD29loCD24+CD61-) cell subpopulations. Microarray profiling was used to derive gene expression signatures of these 4 subpopulations. The four mammary cell subpopulations were found to have distinct gene expression profiles. Four mammary cell subpopulations from 3-5 pooled mouse tissues were analysed. MS is for the MaSC-enriched cell subpopulation. LP is for the Luminal Progenitor subpopulation. ML is for the Mature Luminal subpopulation.

为了刻画小鼠乳腺组织中的上皮细胞亚群，研究人员采用荧光激活细胞分选术（fluorescence-activated cell sorting），从乳腺来源的新鲜制备细胞悬液中去除造血细胞与内皮细胞。由此获得的谱系阴性（Lin⁻）细胞群，利用针对CD29、CD24与CD61的抗体被进一步分为4个独立的细胞亚群。基于免疫组织化学表型、体内与体外功能实验结果，这4个亚群分别被鉴定为：含成纤维细胞的基质细胞群（CD29^loCD24^-）、富集乳腺干细胞（mammary stem cell, MaSC）的细胞群（CD29^hiCD24^+CD61^+）、腔面祖细胞群（CD29^loCD24^+CD61^+）以及成熟腔面细胞群（CD29^loCD24^+CD61^-）。研究人员通过微阵列表达谱分析获取了这4个亚群的基因表达特征谱，结果证实这4个乳腺细胞亚群具有各自独特的基因表达谱。本次分析共使用来自3~5只合并小鼠组织的4个乳腺细胞亚群样本。其中，MS代表富集乳腺干细胞的细胞亚群，LP代表腔面祖细胞亚群，ML代表成熟腔面细胞亚群。