Department of Neurosurgery, Nippon Medical School, Tokyo, Japan.
J Neuroendocrinol. 2009 May;21(5):481-8. doi: 10.1111/j.1365-2826.2009.01867.x.
Stromal cell-derived factor (SDF)-1 and its receptor, CXCR4, have been identified in both neurones and glia of many brain areas. Previous studies have mainly focused on the role of SDF-1 and CXCR4 in modulating the hypothalamic-pituitary axis and their possible involvement in the development of pituitary adenomas. An alternative SDF-1 receptor, CXCR7, has recently been identified, but it has not been studied in the context of pituitary adenomas. The present study aimed to investigate the distribution and function of CXCR7 in pituitary adenomas. The expression of CXCR7, normalised to β-actin, was assessed by tissue microarray analysis of 62 adenomas, including 23 growth hormone (GH)-producing adenomas, 22 nonfunctioning adenomas, seven prolactin (PRL)-producing adenomas, six adrenocorticotrophic hormone-producing adenomas and four thyroid-stimulating hormone-producing adenomas. In vitro functional studies used RNA interference (RNAi) and cDNA microarray analysis to evaluate the CXCR7 signalling pathway in AtT-20 mouse pituitary adenoma cells treated with recombinant mouse SDF-1α and transfected with RNAi against Cxcr7 or control RNAi. In tissue microarray analysis, prominent expression of CXCR7 was observed in GH-producing adenomas and PRL-producing adenomas, and in macroadenomas (P < 0.05). Intracellular signalling via CXCR7 up-regulated Bub1, Cdc29 and Ccnb1, and down-regulated Asns, Gpt, Pycr1, Cars and Dars. The present study demonstrates that the SDF-1α ⁄ CXCR7 signalling pathway regulates genes involved in cell cycle control, amino acid metabolism and ligase activity, which comprise targets that are distinct from those of CXCR4.
基质细胞衍生因子 (SDF)-1 及其受体 CXCR4 已在许多脑区的神经元和神经胶质细胞中被发现。先前的研究主要集中在 SDF-1 和 CXCR4 调节下丘脑-垂体轴的作用及其在垂体腺瘤发生中的可能作用。最近已经确定了替代 SDF-1 受体 CXCR7,但尚未在垂体腺瘤的背景下进行研究。本研究旨在研究 CXCR7 在垂体腺瘤中的分布和功能。通过对 62 例腺瘤(包括 23 例生长激素 (GH) 产生腺瘤、22 例无功能腺瘤、7 例催乳素 (PRL) 产生腺瘤、6 例促肾上腺皮质激素产生腺瘤和 4 例促甲状腺激素产生腺瘤)的组织微阵列分析,评估 CXCR7 的表达情况,通过β-肌动蛋白归一化。体外功能研究使用 RNA 干扰 (RNAi) 和 cDNA 微阵列分析,评估用重组小鼠 SDF-1α 处理和转染 RNAi 针对 Cxcr7 或对照 RNAi 的 AtT-20 小鼠垂体腺瘤细胞中的 CXCR7 信号通路。在组织微阵列分析中,在 GH 产生腺瘤和 PRL 产生腺瘤以及大腺瘤中观察到 CXCR7 的显著表达(P<0.05)。通过 CXCR7 进行的细胞内信号传导上调了 Bub1、Cdc29 和 Ccnb1,并下调了 Asns、Gpt、Pycr1、Cars 和 Dars。本研究表明,SDF-1α/CXCR7 信号通路调节参与细胞周期控制、氨基酸代谢和连接酶活性的基因,这些基因构成了与 CXCR4 不同的靶点。