Huang Yong-Li, Huang Guan-You, Lv Jing, Pan Li-Na, Luo Xi, Shen Jie
Reproductive Medicine Center, The Affiliated Hospital of Guizhou Medical University, Guiyang, China.
Mol Reprod Dev. 2017 Aug;84(8):693-701. doi: 10.1002/mrd.22843. Epub 2017 Jun 29.
Micro RNAs play important roles during mammalian spermatogenesis, but the function(s) of specific miRNAs remain largely unknown. Here, we report that miR-100 is predominantly expressed in undifferentiated murine spermatogonia, including spermatogonial stem cells (SSCs). We utilized a miRNA mimic and inhibitor to knock down and overexpress miR-100 in cultured SSCs, respectively, finding that the miR-100 promotes the proliferation of SSCs in vitro. Furthermore, signals promoting SSC maintenance induced, whereas retinoic acid repressed, expression of miR-100. Stat3 expression was modulated by miR-100, with increased transcript and protein abundance in the presence of the miR-100 inhibitor versus reduced protein levels following miR-100 overexpression. Stat3 silencing also mimicked the reduced SSC proliferation phenotype associated with elevated miR-100 levels. Importantly, Stat3 silencing rescued the anti-proliferation capacity of miR-100 inhibitor on cultured SSCs. Given that the Stat3 3' untranslated region was not repressed by pre-miR-100 in a standard luciferase reporter assay, we suggest that miR-100 promotes SSC proliferation by indirect regulation of Stat3.
微小RNA在哺乳动物精子发生过程中发挥着重要作用，但特定微小RNA的功能仍 largely未知。在此，我们报道miR-100主要在未分化的小鼠精原细胞中表达，包括精原干细胞（SSCs）。我们分别利用微小RNA模拟物和抑制剂在培养的精原干细胞中敲低和过表达miR-100，发现miR-100在体外促进精原干细胞的增殖。此外，促进精原干细胞维持的信号诱导了miR-100的表达，而视黄酸则抑制了miR-100的表达。Stat3的表达受到miR-100的调节，与miR-100过表达后蛋白质水平降低相比，在存在miR-100抑制剂的情况下转录本和蛋白质丰度增加。Stat3沉默也模拟了与miR-100水平升高相关的精原干细胞增殖减少的表型。重要的是，Stat3沉默挽救了miR-100抑制剂对培养的精原干细胞的抗增殖能力。鉴于在标准荧光素酶报告基因检测中，pre-miR-100并未抑制Stat3的3'非翻译区，我们认为miR-100通过间接调节Stat3来促进精原干细胞的增殖。
