Approximately 8% of CD9-, S100β- and SOX2-triple positive (CD9/S100β/SOX2-positive) stem/progenitor cells in the anterior lobe of the rat pituitary gland have previously been shown to differentiate into endothelial cells in vitro, suggesting that they play a role in vascularisation as tissue-resident vascular precursor cells. In the present study, we focused on chemokine ligands to further characterise the CD9/S100β/SOX2-positive cells and found that they distinctively express CX3C chemokine ligand 1 (Cx3cl1). Immunohistochemical analysis of the anterior lobe showed that CX3CL1-positive cells comprised 7.8% in CD9-positive cells. By cultivation of the CD9-positive cells on laminin-coated plates, we observed that the expression levels of Cx3cl1 decreased, while those of Sox18, an endothelial cell-progenitor marker, and Cx3cr1, a CX3CL1 receptor, increased. Furthermore, in a rat model of prolactinoma, the most common pituitary tumour, which is accompanied by frequent neo-vasculogenesis in the anterior lobe, we have confirmed a decrease in Cx3cl1 expression and an increase in Cx3cr1 expression, as well as a prominent increase in Sox18 expression. These findings suggest that CX3CL1/CX3CR1 signalling in CD9/S100β/SOX2-positive cells plays an important role in resupplying endothelial cells for vascular remodelling in the anterior lobe.

在大鼠垂体前叶中，大约有8％的CD9-，S100β-和SOX2三联阳性（CD9 /S100β/ SOX2阳性）干/祖细胞已在体外分化为内皮细胞，这表明它们在血管形成中作为组织驻留的血管前体细胞发挥作用。在本研究中，我们集中于趋化因子配体以进一步表征CD9 /S100β/ SOX2阳性细胞，并发现它们独特地表达CX3C趋化因子配体1（Cx3cl1）。前叶的免疫组织化学分析显示，CX3CL1阳性细胞在CD9阳性细胞中占7.8％。通过在层粘连蛋白包被的板上培养CD9阳性细胞，我们观察到Cx3cl1的表达水平下降，而Cx3cl1的表达水平下降。SOX18，内皮细胞祖标记，CX3CR1，一个CX3CL1受体，增加了。此外，在催乳素瘤（最常见的垂体肿瘤，伴有前叶频繁的新生血管生成）的大鼠模型中，我们已经证实Cx3cl1表达降低，Cx3cr1表达升高以及Cx3cr1表达显着增加。Sox18表达。这些发现表明，CD9 /S100β/ SOX2阳性细胞中的CX3CL1 / CX3CR1信号传导在内皮细胞的前叶血管重构中起重要作用。