Department of Stem Cell Biology, National Institute for Research in Reproductive Health, Mumbai, India.
Stem Cells Dev. 2011 Aug;20(8):1451-64. doi: 10.1089/scd.2010.0461. Epub 2011 Mar 23.
The present study was undertaken to detect, characterize, and study differentiation potential of stem cells in adult rabbit, sheep, monkey, and menopausal human ovarian surface epithelium (OSE). Two distinct populations of putative stem cells (PSCs) of variable size were detected in scraped OSE, one being smaller and other similar in size to the surrounding red blood cells in the scraped OSE. The smaller 1-3 μm very small embryonic-like PSCs were pluripotent in nature with nuclear Oct-4 and cell surface SSEA-4, whereas the bigger 4-7 μm cells with cytoplasmic localization of Oct-4 and minimal expression of SSEA-4 were possibly the tissue committed progenitor stem cells. Pluripotent gene transcripts of Oct-4, Oct-4A, Nanog, Sox-2, TERT, and Stat-3 in human and sheep OSE were detected by reverse transcriptase-polymerase chain reaction. The PSCs underwent spontaneous differentiation into oocyte-like structures, parthenote-like structures, embryoid body-like structures, cells with neuronal-like phenotype, and embryonic stem cell-like colonies, whereas the epithelial cells transformed into mesenchymal phenotype by epithelial-mesenchymal transition in 3 weeks of OSE culture. Germ cell markers like c-Kit, DAZL, GDF-9, VASA, and ZP4 were immuno-localized in oocyte-like structures. In conclusion, as opposed to the existing view of OSE being a bipotent source of oocytes and granulosa cells, mammalian ovaries harbor distinct very small embryonic-like PSCs and tissue committed progenitor stem cells population that have the potential to develop into oocyte-like structures in vitro, whereas mesenchymal fibroblasts appear to form supporting granulosa-like somatic cells. Research at the single-cell level, including complete gene expression profiling, is required to further confirm whether postnatal oogenesis is a conserved phenomenon in adult mammals.
本研究旨在检测、鉴定和研究成年兔、绵羊、猴子和绝经后人类卵巢表面上皮（OSE）中的干细胞特性和分化潜能。在刮取的 OSE 中检测到两种不同大小的假定干细胞（PSCs）群体，一种较小，另一种与刮取的 OSE 中的周围红细胞大小相似。较小的 1-3μm 非常小的胚胎样 PSCs 具有多能性，核内有 Oct-4 和细胞表面 SSEA-4，而较大的 4-7μm 细胞内Oct-4 定位，SSEA-4 表达最低，可能是组织定向祖细胞干细胞。通过逆转录-聚合酶链反应检测到人类和绵羊 OSE 中多能基因转录物 Oct-4、Oct-4A、Nanog、Sox-2、TERT 和 Stat-3。PSCs 自发分化为卵母细胞样结构、孤雌样结构、类胚体样结构、神经元样表型细胞和胚胎干细胞样集落，而上皮细胞在 OSE 培养 3 周时通过上皮-间充质转化转化为间充质表型。在卵母细胞样结构中免疫定位到生殖细胞标志物如 c-Kit、DAZL、GDF-9、VASA 和 ZP4。总之，与 OSE 是卵母细胞和颗粒细胞的双潜能来源的现有观点相反，哺乳动物卵巢中存在独特的非常小的胚胎样 PSCs 和组织定向祖细胞干细胞群体，它们具有在体外发育为卵母细胞样结构的潜力，而间充质成纤维细胞似乎形成支持颗粒细胞样体细胞。需要在单细胞水平进行研究，包括完整的基因表达谱分析，以进一步证实产后卵发生是否是成年哺乳动物中的保守现象。
