Endocrine regulation of spermatogonial stem cells in the seminiferous epithelium of adult mice.
Endocrine regulation of spermatogonial stem cells in the seminiferous epithelium of adult mice.
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DOI：
10.1089/biores.2012.0259
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发表时间：
2012-10
影响因子：
--
通讯作者：
McLean DJ
中科院分区：
文献类型：
--
作者：
Caires KC;de Avila J;McLean DJ
精原干细胞（SSCs）的自我更新和分化之间的平衡是维持整个男性生命的精子生产所必需的。生精上皮根据睾丸管状部分内的生殖细胞类型的互补而组织成精子发生的各个阶段。这些阶段在身体上非常接近，并促进生殖细胞发育的不同阶段，尽管暴露于支持协调精子发生的类似内分泌环境。本研究的目的是确定精原干细胞在体内的群体动力学。我们假设，SSC人口和他们的壁龛是专门分布在小鼠睾丸成熟的生精上皮。为了验证这一假设，我们进行了生殖细胞的干细胞移植，这些生殖细胞是从代表对卵泡刺激素（IX-I）、雄激素（II-IV）和类维生素A（V-VIII）信号传导具有高反应性的区域的生精小管的特定阶段簇中获得的。同样，我们分析了与SSC活动相关的基因在这些阶段组中的表达。SSC移植后，未检测到定殖效率或殖民地数量的阶段特异性差异，表明SSC均匀分布于生精小管的所有阶段。相比之下，从供体阶段IX-IV获得的SSC由于增加的集落扩增而建立了更大的供体来源的集落。源自不同阶段的SSC在体内具有不同程度的干细胞活性，这一概念与Gdnf、Ret和Bcl 6 b表达数据一致。这些结果支持了特定阶段的结论，微环境调节SSC自我更新，并建议存在一个过渡放大人口的未分化精原细胞在体内。
A balance between self-renewal and differentiation of spermatogonial stem cells (SSCs) is required to maintain sperm production throughout male life. The seminiferous epithelium is organized into stages of spermatogenesis based on the complement of germ cell types within a tubular section of the testis. The stages exist in close physical proximity and foster diverse phases of germ cell development despite exposure to a similar endocrine milieu that supports coordinated spermatogenesis. The objective of the current study was to identify the population dynamics of SSCs in vivo. We hypothesized that SSC populations and their niches are specifically distributed across the mature seminiferous epithelium in the mouse testis. To test this hypothesis, we conducted stem cell transplantation of germ cells obtained from stage-specific clusters of seminiferous tubules representing areas of high responsiveness to follicle-stimulating hormone (IX–I), androgen (II–IV), and retinoid (V–VIII) signaling. Similarly, we analyzed the expression of genes linked with SSC activity in these groups of stages. No stage-specific differences in the colonization efficiency or the colony number were detected after SSC transplantation, indicating that SSCs are equally distributed across all stages of the seminiferous tubule. In contrast, SSCs obtained from donor stages IX–IV established larger donor-derived colonies due to increased colony expansion. SSCs originating from different stages have varying degrees of stem cell activity in vivo, a notion consistent with Gdnf, Ret, and Bcl6b expression data. These results support the conclusion of a stage-specific, microenvironment-regulating SSC self-renewal and suggest the presence of a transit-amplifying population of undifferentiated spermatogonia in vivo.