Liang Simon X, Summer Ross, Sun Xi, Fine Alan
Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
Physiol Genomics. 2005 Oct 17;23(2):172-81. doi: 10.1152/physiolgenomics.00059.2005. Epub 2005 Aug 2.
Hoechst-effluxing cells (side population cells) are a rare subset of cells found in adult tissues that are highly enriched for stem and progenitor cell activity. To identify potential stem and progenitor cells during lung development, we generated gene expression profiles for CD45- and CD45+ side population cells in the embryonic day 17.5 lung. We found that side population cells comprise 1% of total embryonic day 17.5 lung cells (55% CD45+, 45% CD45-). Gene profiling data demonstrated an overrepresentation of endothelial genes within the CD45- side population. We used expression of several distinct genes to identify two types of CD45- side population cells: 1) von Willebrand factor+/smooth muscle actin+ cells that reside in the muscular layer of select large vessels and 2) von Willebrand factor+/intercellular adhesion molecule+ cells that reside within the endothelial layer of select small vessels. Gene profiling of the CD45+ side population indicated an overrepresentation of genes associated with myeloid cell differentiation. Consistent with this, culturing CD45+ side population cells was associated with induction of mature dendritic markers (CD86). The microarray results suggested that expression of myeloperoxidase and proteinase-3 might be used to identify CD45+ side population cells. By immunohistochemistry, we found that myeloperoxidase+/proteinase-3+ cells represent a small subset of total CD45+ cells in the embryonic day 17.5 lung and that they reside in the mesenchyme and perivascular regions. This is the first detailed information regarding the phenotype and localization of side population cells in a developing organ.
Hoechst 外流细胞（侧群细胞）是在成体组织中发现的一种罕见细胞亚群，高度富集干细胞和祖细胞活性。为了鉴定肺发育过程中的潜在干细胞和祖细胞，我们生成了胚胎第17.5天肺中CD45 - 和CD45 + 侧群细胞的基因表达谱。我们发现侧群细胞占胚胎第17.5天肺细胞总数的1%（55% CD45 + ，45% CD45 - ）。基因谱数据表明CD45 - 侧群中内皮基因过度表达。我们利用几种不同基因的表达来鉴定两种类型的CD45 - 侧群细胞：1）位于特定大血管肌层的血管性血友病因子 + /平滑肌肌动蛋白 + 细胞，以及2）位于特定小血管内皮层的血管性血友病因子 + /细胞间黏附分子 + 细胞。CD45 + 侧群的基因谱表明与髓样细胞分化相关的基因过度表达。与此一致的是，培养CD45 + 侧群细胞与成熟树突状细胞标志物（CD86）的诱导相关。微阵列结果表明，髓过氧化物酶和蛋白酶 - 3的表达可能用于鉴定CD45 + 侧群细胞。通过免疫组织化学，我们发现髓过氧化物酶 + /蛋白酶 - 3 + 细胞占胚胎第17.5天肺中总CD45 + 细胞的一小部分，它们位于间充质和血管周围区域。这是关于发育器官中侧群细胞表型和定位的首个详细信息。
