The adenohypophysis is composed of the anterior and intermediate lobes (AL and IL), and secretes important hormones for growth, sexual development, metabolism, and reproduction. In the marginal cell layer (MCL) facing Rathke’s cleft between the IL and AL, cluster of differentiation (CD) 9-, CD81-, S100β-, and SOX2-quadruple positive (CD9/CD81/S100β/SOX2-positive) cells in the adult IL are settled as tissue-resident stem/progenitor cells supplying hormone-producing cells to the AL. However, it is unclear how CD9/CD81/S100β/SOX2-positive cells in the IL-side MCL migrate into the AL across Rathke’s cleft. In the present study, we performed chimeric pituitary tissue culture using S100β/GFP-transgenic rats and Wistar rats, and traced the footprint of S100β/GFP-expressing cells. We detected IL-side S100β/GFP-expressing cells in the AL tissue, demonstrating that these cells migrate from the IL to the AL. However, the cells failed to migrate in the opposite direction. Consistently, scanning electron microscopic analysis revealed well-developed cytoplasmic protrusions in the IL-side MCL, but not in the AL-side MCL, suggesting that IL-side CD9/CD81/S100β/SOX2-positive cells had higher migratory activity. We also searched for a specific marker for IL-side CD9/CD81/S100β/SOX2-positive cells and identified tetraspanin 1 (TSPAN1) from microarray analysis. Downregulation of Tspan1 by specific siRNA impaired cell migration and significantly reduced expression of snail family transcriptional repressor 2 (Slug), a marker of epithelial-mesenchymal transition (EMT). Therefore, CD9/CD81/S100β/SOX2-positive cells in the IL-side MCL can be stem/progenitor cells that provide stem/progenitor cells to the AL-side MCL via SLUG-mediated EMT and cell migration.

腺垂体由前叶和中叶（AL和IL）组成，分泌对生长、性发育、新陈代谢和生殖重要的激素。在 IL 和 AL 之间面向 Rathke 裂隙的边缘细胞层 (MCL) 中，分化簇 (CD) 9-、CD81-、S100β-和 SOX2-四联阳性 (CD9/CD81/S100β/SOX2-阳性) 细胞成人 IL 被固定为组织驻留干细胞/祖细胞，向 AL 提供激素产生细胞。然而，尚不清楚 IL 侧 MCL 中的 CD9/CD81/S100β/SOX2 阳性细胞如何通过 Rathke 的裂隙迁移到 AL 中。在本研究中，我们使用 S100β/GFP 转基因大鼠和 Wistar 大鼠进行嵌合垂体组织培养，并追踪 S100β/GFP 表达细胞的足迹。我们在 AL 组织中检测到 IL 侧 S100β/GFP 表达细胞，证明这些细胞从IL迁移到AL。然而，细胞未能向相反方向迁移。一致地，扫描电子显微镜分析显示IL侧MCL中发育良好的细胞质突起，但AL侧MCL中没有，表明IL侧CD9/CD81/S100β/SOX2阳性细胞具有更高的迁移活性。我们还搜索了 IL 侧 CD9/CD81/S100β/SOX2 阳性细胞的特异性标记，并从微阵列分析中鉴定了四跨膜蛋白 1 (TSPAN1)。下调 表明 IL 侧 CD9/CD81/S100β/SOX2 阳性细胞具有更高的迁移活性。我们还搜索了 IL 侧 CD9/CD81/S100β/SOX2 阳性细胞的特异性标记，并从微阵列分析中鉴定了四跨膜蛋白 1 (TSPAN1)。下调 表明 IL 侧 CD9/CD81/S100β/SOX2 阳性细胞具有更高的迁移活性。我们还搜索了 IL 侧 CD9/CD81/S100β/SOX2 阳性细胞的特异性标记，并从微阵列分析中鉴定了四跨膜蛋白 1 (TSPAN1)。下调Tspan1通过特异性 siRNA 损害细胞迁移并显着降低蜗牛家族转录抑制因子 2 ( Slug ) 的表达，这是上皮间质转化 (EMT) 的标志物。因此，IL 侧 MCL 中的 CD9/CD81/S100β/SOX2 阳性细胞可以是干/祖细胞，通过 SLUG 介导的 EMT 和细胞迁移向 AL 侧 MCL 提供干/祖细胞。