Ichise Hirotake, Ichise Taeko, Yoshida Nobuaki
Laboratory of Developmental Genetics, Center for Experimental Medicine and Systems Biology, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan.
PLoS One. 2016 Mar 7;11(3):e0150521. doi: 10.1371/journal.pone.0150521. eCollection 2016.
Phospholipase Cγ2 (PLCγ2)-deficient mice exhibit misconnections of blood and lymphatic vessels, and male infertility. However, the cell type responsible for vascular partitioning and the mechanism for male infertility remain unknown. Accordingly, we generated a mouse line that conditionally expresses endogenous Plcg2 in a Cre/loxP recombination-dependent manner, and found that Tie2-Cre- or Pf4-Cre-driven reactivation of Plcg2 rescues PLCγ2-deficient mice from the vascular phenotype. By contrast, male mice rescued from the vascular phenotype exhibited epididymal sperm granulomas. As judged from immunostaining, PLCγ2 was expressed in clear cells in the epididymis. PLCγ2 deficiency did not compromise differentiation of epididymal epithelial cells, including clear cells, and tube formation at postnatal week 2. However, luminal expansion of the epididymal duct was impaired during the prepubertal period, regardless of epithelial cell polarity and tube architecture. These results suggest that PLCγ2-deficient clear cells cause impaired luminal expansion, stenosis of the epididymal duct, attenuation of luminal flow, and subsequent sperm granulomas. Clear cell-mediated luminal expansion is also supported by the observation that PLCγ2-deficient males were rescued from infertility by epididymal epithelium-specific reactivation of Plcg2, although the edematous and hemorrhagic phenotype associated with PLCγ2 deficiency also caused spontaneous epididymal sperm granulomas in aging males. Collectively, our findings demonstrate that PLCγ2 in clear cells plays an essential role in luminal expansion of the epididymis during the prepubertal period in mice, and reveal an unexpected link between PLCγ2, clear cells, and epididymal development.
磷脂酶Cγ2（PLCγ2）缺陷型小鼠表现出血液和淋巴管连接错误以及雄性不育。然而，负责血管分隔的细胞类型和雄性不育的机制仍然未知。因此，我们构建了一种以Cre/loxP重组依赖方式条件性表达内源性Plcg2的小鼠品系，发现Tie2-Cre或Pf4-Cre驱动的Plcg2重新激活可使PLCγ2缺陷型小鼠从血管表型中恢复。相比之下，从血管表型中恢复的雄性小鼠表现出附睾精子肉芽肿。通过免疫染色判断，PLCγ2在附睾的透明细胞中表达。PLCγ2缺陷并不影响附睾上皮细胞（包括透明细胞）的分化以及出生后第2周的管腔形成。然而，在青春期前阶段，附睾管腔的扩张受损，与上皮细胞极性和管腔结构无关。这些结果表明，PLCγ2缺陷的透明细胞导致管腔扩张受损、附睾管狭窄、管腔液流减弱以及随后的精子肉芽肿。PLCγ2缺陷型雄性小鼠通过附睾上皮特异性重新激活Plcg2从不育中恢复，这一观察结果也支持了透明细胞介导的管腔扩张，尽管与PLCγ2缺陷相关的水肿和出血表型也在衰老雄性小鼠中导致了自发性附睾精子肉芽肿。总体而言，我们的研究结果表明，透明细胞中的PLCγ2在小鼠青春期前阶段附睾管腔扩张中起关键作用，并揭示了PLCγ2、透明细胞和附睾发育之间意想不到的联系。
