Prolactin induces MFG-E8 production in macrophages via transcription factor C/EBPβ-dependent pathway
Prolactin induces MFG-E8 production in macrophages via transcription factor C/EBPβ-dependent pathway
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DOI：
10.1007/s10495-008-0201-1
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发表时间：
2008-05-01
期刊：
影响因子：
7.2
通讯作者：
Kinoshita, Yoshikazu
中科院分区：
文献类型：
--
作者：
Aziz, Md. Monowar;Ishihara, Shunji;Kinoshita, Yoshikazu
泌乳激素（PRL）调节乳腺中乳蛋白基因的表达。为了维持体内的稳态平衡，乳脂球表皮生长因子8 （MFG-E8）对凋亡细胞的吞噬清除至关重要。我们通过评估PRL的启动子功能来研究PRL对巨噬细胞MFG-E8表达的影响。用PRL刺激巨噬细胞，采用real-time PCR和Western blotting检测MFG-E8的表达。显微镜观察MFG-E8对PRL处理的巨噬细胞吞噬凋亡细胞的作用，荧光素酶法观察PRL对MFG-E8表达的反应。PRL处理后，巨噬细胞中PRL受体和MFG-E8的表达明显上调，但PRL处理后的巨噬细胞更有效地吞噬凋亡细胞。MFG-E8启动子分析结果显示，PRL处理后巨噬细胞中启动子活性显著上调，MFG-E8启动子突变分析结果表明，C/EBP β结合位点是PRL诱导MFG-E8启动子活化的原因。电泳迁移迁移试验（EMSA）发现，在prl处理的细胞中，C/EBP β活性上调。综上所述，PRL是巨噬细胞中MFG-E8表达的有效诱导剂，其作用是通过MFG-E8启动子中应答元件的存在介导的。
The lactogenic hormone prolactin (PRL) regulates milk protein gene expression in mammary glands. To maintain homeostatic balance in the body, milk fat globule epidermal growth factor 8 (MFG-E8) is vital for phagocytic clearance of apoptotic cells. We investigated the effects of PRL on MFG-E8 expression in macrophages by evaluating its promoter function. Macrophages were stimulated with PRL, and the expression of MFG-E8 was determined using real-time PCR and Western blotting. The role of MFG-E8 on phagocytosis of apoptotic cells in PRL-treated macrophages was assessed using microscopy, while the response of PRL to MFG-E8 expression was evaluated using luciferase assay. Following treatment with PRL, significant up-regulations of the PRL receptor and MFG-E8 were observed in macrophages, though PRL-treated macrophages more efficiently engulfed apoptotic cells. The results of MFG-E8 promoter analysis showed considerable up-regulation of promoter activity in macrophages following PRL treatment and results from mutation analysis of the MFG-E8 promoter suggested that the C/EBP beta binding site was responsible for PRL-induced activation of the MFG-E8 promoter. C/EBP beta activity was found to be up-regulated in PRL-treated cells as revealed by an electrophoretic mobility shift assay (EMSA). In conclusion, PRL is a potent inducer of MFG-E8 expression in macrophages, while its effect is mediated by the presence of a responsive element in the MFG-E8 promoter.