Song Jiazhe, Ding Fangrong, Li Song, Li Wenzhe, Li Ning, Xue Kai
a College of Basic Medical Sciences, Dalian Medical University, Dalian, P. R. China.
b State Key Laboratories for AgroBiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China.
Biochem Cell Biol. 2018 Oct;96(5):539-547. doi: 10.1139/bcb-2017-0177. Epub 2018 Apr 5.
Stem cell biology offers promise for understanding the origins of the mammary gland. However, the distribution of mammary stem cell (MaSC) activities at earlier embryonic stages has not been fully identified. The markers for sorting adult MaSC, CD24, CD29, and CD49f have been applied to analyze fetal MaSCs. Here we explored mammary anlagen MaSCs by investigating the expression of CD24 and CD49f. According to the comparative analysis between adult mammary gland and fetal mammary anlagen, we found that fetal mouse mammary anlagen may possess a high percentage of potential MaSCs. Flow cytometry analysis revealed 2 distinct mammary anlagen populations: LinCD24 and LinCD24. Sphere-forming and mammary repopulating assays confirmed that the stem cell activity of E14.5 mouse mammary anlagen was restricted to the LinCD24 cell population. Furthermore, CD24 mammary anlagen cells were separated into LinCD24CD49f and LinCD24CD49f populations and identified, respectively. The results proved that the mammary anlagen LinCD24CD49f cell population possesses more stem cell activities than the LinCD24CD49f cell population. However, a limited numbers of stem cells and large numbers of stromal cells were identified in mammary anlagen in the LinCD24 cell population.
干细胞生物学为理解乳腺的起源提供了希望。然而，乳腺干细胞（MaSC）活性在早期胚胎阶段的分布尚未完全明确。用于分选成年MaSC的标志物CD24、CD29和CD49f已被应用于分析胎儿MaSC。在此，我们通过研究CD24和CD49f的表达来探索乳腺原基MaSC。根据成年乳腺与胎儿乳腺原基之间的比较分析，我们发现胎儿小鼠乳腺原基可能含有高比例的潜在MaSC。流式细胞术分析揭示了2个不同的乳腺原基群体：Lin-CD24⁻和Lin-CD24⁺。成球和乳腺再植实验证实，E14.5小鼠乳腺原基的干细胞活性局限于Lin-CD24⁺细胞群体。此外，CD24⁺乳腺原基细胞被分离为Lin-CD24⁺CD49f⁻和Lin-CD24⁺CD49f⁺群体并分别进行鉴定。结果证明，乳腺原基Lin-CD24⁺CD49f⁺细胞群体比Lin-CD24⁺CD49f⁻细胞群体具有更多的干细胞活性。然而，在Lin-CD24⁺细胞群体的乳腺原基中鉴定出的干细胞数量有限且基质细胞数量众多。
