Differential RA responsiveness among subsets of mouse late progenitor spermatogonia.
Differential RA responsiveness among subsets of mouse late progenitor spermatogonia.
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DOI：
10.1530/rep-21-0031
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发表时间：
2021-05-05
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影响因子：
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通讯作者：
Hermann BP
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文献类型：
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作者：
Suzuki S;McCarrey JR;Hermann BP
小鼠睾丸精原细胞分化的启动始于对维甲酸（RA）的反应，其特征在于KIT和STRA 8表达的激活。在成人中，精原细胞分化是时空协调的脉冲RA每8.6天，是本地化的阶段VII-VIII的生精上皮细胞周期。教条地说，在这些阶段表达维甲酸受体γ（RARG）的祖细胞精原细胞将在对RA的反应中分化，但这尚未在功能上进行测试。先前的单细胞RNA-seq数据鉴定了精原干细胞（SSC）和祖精原细胞的表型和功能不同的子集，其中晚期祖精原细胞通过RARG和Dppa 3的表达来定义。在这里，我们发现晚期祖细胞精原细胞（RARGhigh KIT-）根据Dppa 3报告基因表达进一步分为两个亚群（Dppa 3-ECFP或Dppa 3-EGFP），并且在生精上皮周期的所有阶段都进行了观察。然而，几乎所有的Dppa 3+精原细胞分化（KIT+）晚期生精上皮周期（阶段X-XII），而Dppa 3-晚期祖细胞仍然丰富，这表明Dppa 3+和Dppa 3-晚期祖细胞差异响应RA。在急性RA处理（2- 4小时）后，与Dppa 3-晚期祖细胞相比，显著更多的Dppa 3+晚期祖细胞诱导KIT，包括在周期的中点（阶段VI-IX）。随后，单细胞分析表明Dppa 3+晚期祖细胞的子集表达更高水平的Rxra，我们通过RXRA整体免疫染色证实。总之，这些结果表明RARG单独是不足以启动一个精原细胞反应RA在成年小鼠睾丸，并建议差异RXRA表达可能会歧视响应细胞。
Initiation of spermatogonial differentiation in the mouse testis begins with the response to retinoic acid (RA) characterized by activation of KIT and STRA8 expression. In the adult, spermatogonial differentiation is spatiotemporally coordinated by a pulse of RA every 8.6 days that is localized to stages VII-VIII of the seminiferous epithelial cycle. Dogmatically, progenitor spermatogonia that express retinoic acid receptor gamma (RARG) at these stages will differentiate in response to RA, but this has yet to be tested functionally. Previous single-cell RNA-seq data identified phenotypically and functionally distinct subsets of spermatogonial stem cells (SSCs) and progenitor spermatogonia, where late progenitor spermatogonia were defined by expression of RARG and Dppa3. Here, we found late progenitor spermatogonia (RARGhigh KIT-) were further divisible into two subpopulations based on Dppa3 reporter expression (Dppa3-ECFP or Dppa3-EGFP) and were observed across all stages of the seminiferous epithelial cycle. However, nearly all Dppa3+ spermatogonia were differentiating (KIT+) late in the seminiferous epithelial cycle (stages X-XII), while Dppa3- late progenitors remained abundant, suggesting that Dppa3+ and Dppa3- late progenitors differentially responded to RA. Following acute RA treatment (2–4hr), significantly more Dppa3+ late progenitors induced KIT, including at the midpoint of the cycle (stages VI-IX), than Dppa3- late progenitors. Subsequently, single-cell analyses indicated a subset of Dppa3+ late progenitors expressed higher levels of Rxra, which we confirmed by RXRA whole-mount immunostaining. Together, these results indicate RARG alone is insufficient to initiate a spermatogonial response to RA in the adult mouse testis and suggest differential RXRA expression may discriminate responding cells.