Androgen-Dependent Sertoli Cell Tight Junction Remodeling Is Mediated by Multiple Tight Junction Components
Androgen-Dependent Sertoli Cell Tight Junction Remodeling Is Mediated by Multiple Tight Junction Components
复制标题
DOI：
10.1210/me.2013-1134
复制
发表时间：
2014-07-01
影响因子：
--
通讯作者：
Braun, Robert E.
中科院分区：
文献类型：
--
作者：
Chakraborty, Papia;Buaas, F. William;Braun, Robert E.
生精上皮的支持细胞紧密连接（SCTJ）在睾丸中创造了一个特殊的微环境，以帮助精母细胞和精细胞从精原干细胞分化。 SCTJ 必须长期断裂并以高保真度重建，以允许前细线精母细胞从基底上皮室迁移到腔内上皮室。支持细胞雄激素信号传导受损会扰乱 SCTJ 重塑。 Claudin (CLDN) 3 是雄激素调节下的紧密连接成分，定位于新形成的 SCTJ，并且在支持细胞雄激素受体敲除 (SCARKO) 小鼠中不存在。我们在此表明，Cldn3 缺失小鼠不会复制 SCARKO 小鼠的表型：Cldn3(-/-) 小鼠具有生育能力，显示出不间断的精子发生，并且基于成像和小分子示踪剂分析显示出功能齐全的 SCTJ，这表明其他雄激素调节基因必定对 SCARKO 表型有贡献。为了进一步研究在 SCARKO 突变体中观察到的 SCTJ 表型，我们生成了一个新的 SCARKO 模型，并广泛分析了其他紧密连接组件的表达。除了 Cldn3 之外，我们还发现了其他几种 SCTJ 分子的表达改变，包括 Cldn13 和非经典紧密连接蛋白 2 亚型 (Tjp2iso3) 的下调。染色质免疫沉淀用于证明雄激素受体与这些靶基因区域的直接结合。此外，我们证明 CLDN13 是 SCTJ 的组成部分，并且 TJP2iso3 与三细胞连接的组成部分三纤维素共定位，强调了雄激素信号传导在调节双细胞和三细胞支持细胞紧密连接中的重要性。
Sertoli cell tight junctions (SCTJs) of the seminiferous epithelium create a specialized microenvironment in the testis to aid differentiation of spermatocytes and spermatids from spermatogonial stem cells. SCTJs must be chronically broken and rebuilt with high fidelity to allow the transmigration of preleptotene spermatocytes from the basal to adluminal epithelial compartment. Impairment of androgen signaling in Sertoli cells perturbs SCTJ remodeling. Claudin (CLDN) 3, a tight junction component under androgen regulation, localizes to newly forming SCTJs and is absent in Sertoli cell androgen receptor knockout (SCARKO) mice. We show here that Cldn3-null mice do not phenocopy SCARKO mice: Cldn3(-/-) mice are fertile, show uninterrupted spermatogenesis, and exhibit fully functional SCTJs based on imaging and small molecule tracer analyses, suggesting that other androgen-regulated genes must contribute to the SCARKO phenotype. To further investigate the SCTJ phenotype observed in SCARKO mutants, we generated a new SCARKO model and extensively analyzed the expression of other tight junction components. In addition to Cldn3, we identified altered expression of several other SCTJ molecules, including down-regulation of Cldn13 and a noncanonical tight junction protein 2 isoform (Tjp2iso3). Chromatin immunoprecipitation was used to demonstrate direct androgen receptor binding to regions of these target genes. Furthermore, we demonstrated that CLDN13 is a constituent of SCTJs and that TJP2iso3 colocalizes with tricellulin, a constituent of tricellular junctions, underscoring the importance of androgen signaling in the regulation of both bicellular and tricellular Sertoli cell tight junctions.