Localization of interleukin-18 and its receptor in somatotrophs of the bovine anterior pituitary gland
Localization of interleukin-18 and its receptor in somatotrophs of the bovine anterior pituitary gland
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DOI：
10.1007/s00441-005-0016-0
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发表时间：
2005-07
影响因子：
3.6
通讯作者：
Y. Nagai;T. Nochi;Kouichi Watanabe;Keisuke Watanabe;H. Aso;H. Kitazawa;M. Matsuzaki;S. Ohwada;Takahiro Yamaguchi
中科院分区：
文献类型：
--
作者：
Y. Nagai;T. Nochi;Kouichi Watanabe;Keisuke Watanabe;H. Aso;H. Kitazawa;M. Matsuzaki;S. Ohwada;Takahiro Yamaguchi
促炎细胞因子白细胞介素18（IL-18）诱导IL-1的细胞内表达和IL-6的释放。在垂体前叶细胞中检测到IL-1和IL-6，表明IL-18在垂体前叶细胞中产生，并可能有助于免疫内分泌调节。在本研究中，我们解决了这一假设，通过调查细胞内定位的IL-18及其受体在牛垂体前叶。RT-PCR和Western blotting检测垂体前叶IL-18 mRNA及其蛋白表达。原位杂交结果显示，IL-18 mRNA在垂体前叶细胞中有表达。IL-18和特定激素的免疫组织化学显示生长激素细胞中存在IL-18。免疫激光显微切割证实IL-18免疫反应阳性细胞表达GH mRNA。这些结果首次证明了生长激素细胞产生IL-18。随后，研究了IL-18受体α（IL-18 R α）的分布，以了解垂体前叶细胞中的IL-18信号传导。对牛IL-18 R α cDNA进行部分序列测定，并采用RT-PCR方法在垂体前叶中检测到IL-18 R α基因。IL-18 R α、IL-18和GH的免疫组化结果显示，IL-18 R α共定位于IL-18免疫反应阳性细胞或生长激素细胞。这些数据表明，IL-18通过自分泌途径作为免疫内分泌介质作用于生长激素细胞。
A pro-inflammatory cytokine, interleukin 18 (IL-18), induces intracellular expression of IL-1 and the release of IL-6. IL-1 and IL-6 has been detected in anterior pituitary cells, suggesting that IL-18 is produced in anterior pituitary cells and may serve to aid immuno-endocrine regulation. In the present study, we addressed this hypothesis by investigating the intracellular localization of IL-18 and its receptor in bovine anterior pituitary gland. IL-18 mRNA and its protein were detected in the anterior pituitary gland by RT-PCR and Western blotting. In situ hybridization showed that IL-18 mRNA was expressed in the anterior pituitary cells. Immunohistochemistry of IL-18 and specific hormones revealed the presence of IL-18 in somatotrophs. Furthermore, the expression of GH mRNA in IL-18 immunoreactive cells was confirmed by immuno-laser microdissection. These results first demonstrated that somatotrophs produced IL-18. Subsequently, the distribution of the IL-18 receptor alpha (IL-18Rα) was investigated in order to understand IL-18 signaling among the anterior pituitary cells. Bovine IL-18Rα cDNA was partially sequenced and detected in the anterior pituitary gland by RT-PCR. Immunohistochemistry of IL-18Rα, IL-18 and GH showed that IL-18Rα was co-localized in IL-18 immunoreactive cells or somatotrophs. These data suggest that IL-18 acts on somatotrophs as an immuno-endocrine mediator through the autocrine pathway.