Irwin J C, Suen L F, Faessen G H, Popovici R M, Giudice L C
Division of Reproductive Endocrinology and Infertility, Center for Research on Women's Health and Reproductive Medicine, Department of Gynecology and Obstetrics, Stanford University School of Medicine, California 94305-5317, USA.
J Clin Endocrinol Metab. 2001 May;86(5):2060-4. doi: 10.1210/jcem.86.5.7451.
In human pregnancy, insulin-like growth factor (IGF)-II messenger RNA (mRNA) is expressed at the maternal-fetal interface exclusively by the placental trophoblast. Highest levels are expressed by the invading extravillous trophoblasts, which also secrete matrix metalloproteinases as they degrade the decidual extracellular matrix. In contrast, the maternal decidua expresses high levels of IGF-binding protein (IGFBP)-1 and tissue inhibitors of matrix metalloproteinase (TIMPs), both of which inhibit trophoblast invasiveness in vitro. The present study investigated the hypothesis that IGF-II may serve as a paracrine modulator of maternal restraints on invasion, by examining its effects on TIMP-3 and IGFBP-1 expression by decidualized endometrial stromal cells. Human endometrial stromal cells were decidualized in vitro with progesterone (P), after which 0-130 nM IGF-II and IGF analogs were added. IGFBP-1 in conditioned medium was assayed by immunoradiometric assay. In addition, Northern analyses were conducted using a PCR-generated 421-bp complementary DNA (cDNA) fragment corresponding to nucleotides 132-553 of the human TIMP-3 cDNA, and a 934-bp EcoRI fragment of the human IGFBP-1 cDNA. TIMP-3 mRNA transcripts of 2.2, 2.5, and 4.4 kilobases were detected in decidualized stromal cells not treated with IGF-II, but not detected in nondecidualized stromal cells, consistent with its known induction upon decidualization and in response to P. In decidualized stromal cells, IGF-II and Des(1-6) IGF-II, an analog with reduced affinity for IGFBPs, caused a dose-dependent inhibition of TIMP-3 mRNA expression. Long R(3) IGF-I, an IGF analog with minimal affinity for IGFBPs, also significantly inhibited (79 +/- 0.3%) TIMP-3 mRNA expression in these cells at 6 nM. Decidualized stromal cells secreted IGFBP-1 and expressed a 1.5-kilobase IGFBP-1 transcript, which was not detected in nondecidualized cells, consistent with its known induction upon decidualization and in response to P. IGF-II caused a dose-dependent inhibition of IGFBP-1 mRNA expression and protein secretion in decidualized stromal cells when added in molar excess of endogenous IGFBP-1 levels, with virtually complete inhibition at higher concentrations of IGF-II (65 and 130 nM). By comparison, Long R(3) IGF-I inhibited IGFBP-1 expression with a 50% effective dose of 0.2-0.4 nM. These data suggest that the invading trophoblast has the capacity, via IGF-II, to inhibit maternal restraints on trophoblast invasiveness by regulating decidual TIMP-3 and IGFBP-1.
在人类妊娠过程中，胰岛素样生长因子（IGF）-II信使核糖核酸（mRNA）仅由胎盘滋养层细胞在母胎界面表达。侵入的绒毛外滋养层细胞表达水平最高，它们在降解蜕膜细胞外基质时还分泌基质金属蛋白酶。相比之下，母体蜕膜表达高水平的IGF结合蛋白（IGFBP）-1和基质金属蛋白酶组织抑制剂（TIMPs），这两种物质在体外均抑制滋养层细胞的侵袭性。本研究通过检测IGF-II对蜕膜化子宫内膜基质细胞中TIMP-3和IGFBP-1表达的影响，探讨了IGF-II可能作为母体对侵袭的抑制作用的旁分泌调节因子这一假说。人子宫内膜基质细胞在体外经孕酮（P）诱导蜕膜化，之后加入0 - 130 nM的IGF-II和IGF类似物。用免疫放射分析法检测条件培养基中的IGFBP-1。此外，使用对应于人TIMP-3 cDNA核苷酸132 - 553的421 bp聚合酶链反应（PCR）生成的互补DNA（cDNA）片段以及人IGFBP-1 cDNA的934 bp EcoRI片段进行Northern分析。在未用IGF-II处理的蜕膜化基质细胞中检测到2.2、2.5和4.4千碱基的TIMP-3 mRNA转录本，但在未蜕膜化的基质细胞中未检测到，这与其在蜕膜化时以及对P的反应中已知的诱导情况一致。在蜕膜化基质细胞中，IGF-II和对IGFBPs亲和力降低的类似物Des(1 - 6) IGF-II导致TIMP-3 mRNA表达呈剂量依赖性抑制。对IGFBPs亲和力最小的IGF类似物长R(3) IGF-I在6 nM时也显著抑制（79±0.3%）这些细胞中TIMP-3 mRNA的表达。蜕膜化基质细胞分泌IGFBP-1并表达1.5千碱基的IGFBP-1转录本，在未蜕膜化细胞中未检测到，这与其在蜕膜化时以及对P的反应中已知的诱导情况一致。当以摩尔过量于内源性IGFBP-1水平加入时，IGF-II导致蜕膜化基质细胞中IGFBP-1 mRNA表达和蛋白分泌呈剂量依赖性抑制，在较高浓度的IGF-II（65和130 nM）时几乎完全抑制。相比之下，长R(3) IGF-I抑制IGFBP-1表达的半数有效剂量为0.2 - 0.4 nM。这些数据表明，侵入的滋养层细胞有能力通过IGF-II，通过调节蜕膜TIMP-3和IGFBP-1来抑制母体对滋养层细胞侵袭性的抑制作用。
