Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
J Endocrinol. 2012 Mar;212(3):363-70. doi: 10.1530/JOE-11-0433. Epub 2011 Dec 19.
Folliculostellate (FS) cells of the anterior pituitary gland express a variety of regulatory molecules. Using transgenic rats that express green fluorescent protein specifically in FS cells, we recently demonstrated that FS cells in vitro showed marked changes in motility, proliferation, and that formation of cellular interconnections in the presence of laminin, a component of the extracellular matrix, closely resembled those observed in vivo. These findings suggested that FS cells express matrix metalloproteinase-9 (MMP-9), which assists their function on laminin. In the present study, we investigate MMP-9 expression in rat anterior pituitary gland and examine its role in motility and proliferation of FS cells on laminin. Immunohistochemistry, RT-PCR, immunoblotting, and gelatin zymography were performed to assess MMP-9 expression in the anterior pituitary gland and cultured FS cells. Real-time RT-PCR was used to quantify MMP-9 expression in cultured FS cells under different conditions and treatments. MMP-9 expression was inhibited by pharmacological inhibitor or downregulated by siRNA and time-lapse images were acquired. A 5-bromo-2'-deoxyuridine assay was performed to analyze the proliferation of FS cells. Our results showed that MMP-9 was expressed in FS cells, that this expression was upregulated by laminin, and that laminin induced MMP-9 secretion by FS cells. MMP-9 inhibition and downregulation did not impair FS motility; however, it did impair the capacity of FS cells to form interconnections and it significantly inhibited proliferation of FS cells on laminin. We conclude that MMP-9 is necessary in FS cell interconnection and proliferation in the presence of laminin.
垂体前叶的滤泡星状细胞表达多种调节分子。我们最近使用特异性在滤泡星状细胞中表达绿色荧光蛋白的转基因大鼠证明，体外的滤泡星状细胞在层粘连蛋白存在的情况下表现出明显的运动性、增殖性和细胞连接形成的变化，与体内观察到的变化非常相似。这些发现表明，滤泡星状细胞表达基质金属蛋白酶-9（MMP-9），它有助于它们在层粘连蛋白上的功能。在本研究中，我们研究了大鼠垂体前叶中 MMP-9 的表达，并检查了其在 MMP-9 对层粘连蛋白上的 FS 细胞运动性和增殖的作用。通过免疫组织化学、RT-PCR、免疫印迹和明胶酶谱分析评估垂体前叶和培养的 FS 细胞中的 MMP-9 表达。使用实时 RT-PCR 定量分析了不同条件和处理下培养的 FS 细胞中 MMP-9 的表达。用药理学抑制剂抑制 MMP-9 表达或用 siRNA 下调 MMP-9 表达，并获取延时图像。进行 5-溴-2'-脱氧尿苷测定以分析 FS 细胞的增殖。结果表明，MMP-9 在 FS 细胞中表达，层粘连蛋白可上调其表达，且层粘连蛋白可诱导 FS 细胞分泌 MMP-9。MMP-9 抑制和下调不影响 FS 细胞的运动性，但会损害 FS 细胞形成连接的能力，并显著抑制 FS 细胞在层粘连蛋白上的增殖。我们得出结论，MMP-9 是 FS 细胞在层粘连蛋白存在下连接和增殖所必需的。
