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Physiological significance of placental leucine aminopeptidase /oxytocinase at the interface between mother and fetus

母胎界面胎盘亮氨酸氨肽酶/催产素酶的生理意义

基本信息

批准号：
13671705
负责人：
NOMURA Seiji
金额：
$ 2.24万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

We firstly demonstrated that the region from-297 to-94, which contains four footprint sites (FP1 to FP4), is important for transcription in choriocarcinoma trophoblastic cells. AP-2α, AP-2γ, and Ikaros binding to FP3 (-214 to -183) was important for high promoter activity in these cells. Functional analysis showed that AP-2 is critical for human P-LAP gene expression and Ikaros cooperates with AP-2 to induce maximal promoter activity. This is apparently the first result that Ikaros, initially characterized as a lymphoid-restricted transcriptional factor, is expressed in trophoblasts. P-LAP promoter region contains putative binding sites for cytokine-induced transcription factors. We therefore postulated that inflammatory cytokines suppress P-LAP expression in trophoblasts. Interleukin-1beta (IL-1β) increased P-LAP activity and proteins. Semi-quantitative RT-PCR and Southern blotting showed that IL-1β also increased P-LAP mRNA, which was abrogated by prior exposure to cycloheximide. Luciferase assays did not reveal any regulatory regions that could explain IL-1β-induced P-LAP mRNA accumulation. Immunohistochemical analysis of the human placenta with chorioamnionitis demonstrated prominent P-LAP staining at sites of abundant inflammatory cell infiltration. These findings indicated that prolonged exposure to IL-1β induces P-LAP in the placenta, possibly via other de novo protein synthesis. Transmission immunoelectron microscopy revealed that P-LAP was expressed on the surface of apical microvilli of syncytiotrophoblast cells. Our observation that P-LAP is present on the microvilli, which is a site of interaction between the mother and fetus, suggests possible involvement of these enzymes in cleaving peptide hormones from the fetus and mother in order to regulate bioactivity.

我们首次证明了从-297到-94的区域，其中包含四个足迹位点（FP 1到FP 4），是重要的绒毛膜癌滋养层细胞的转录。AP-2α、AP-2γ和Ikaros与FP 3（-214至-183）的结合对于这些细胞中的高启动子活性很重要。功能分析表明AP-2对人P-gp基因的表达至关重要，Ikaros与AP-2协同作用可诱导最大的启动子活性。这显然是第一个结果，Ikaros，最初的特点是作为一个淋巴限制性转录因子，在滋养层细胞中表达。P-gp启动子区含有推测的结合位点，为丝氨酸诱导的转录因子。因此，我们推测炎症细胞因子抑制滋养层细胞中P-gp的表达。白细胞介素-1 β（IL-1β）增加P-LAP活性和蛋白质。半定量RT-PCR和Southern杂交结果显示，IL-1β还可增加P-gp mRNA的表达，而放线菌酮可抑制P-gp的表达。荧光素酶测定没有发现任何可以解释IL-1β诱导的P-LAP mRNA积累的调节区域。免疫组化分析显示，在大量炎性细胞浸润的部位，胎盘绒毛膜炎的胎盘组织中有明显的P-β染色。这些发现表明，长期暴露于IL-1β诱导胎盘中的P-CRP，可能通过其他从头蛋白质合成。透射免疫电镜显示，P-gp表达于合体滋养层细胞顶端微绒毛表面。我们观察到，P-glutamate是目前的微绒毛，这是一个网站之间的相互作用的母亲和胎儿，表明这些酶可能参与切割肽激素从胎儿和母亲，以调节生物活性。