Department of Obstetrics and Gynecology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
Placenta. 2013 Nov;34(11):1036-43. doi: 10.1016/j.placenta.2013.08.004. Epub 2013 Aug 20.
The invasion of extravillous trophoblasts (EVTs) to the decidua and spiral arteries in early pregnancy is a crucial step for a successful pregnancy; however, its mechanisms are not fully understood. Lipocalin2 (LCN2), a multifunctional secretory protein known as neutrophil gelatinase-associated lipocalin (NGAL), reportedly enhanced invasiveness via the activation of matrix metalloproteinase-9 (MMP-9) in several cancer cells. In this study, the expression and function of LCN2 in early placenta were analyzed.
Early placental tissues between 7 and 10 weeks of gestation were obtained from normal pregnant women who underwent elective termination. The expression of LCN2 was examined using immunostaining and RT-PCR. EVTs isolated from these placental tissues and a choriocarcinoma cell line (JAR) were used to investigate the effects of LCN2 on proliferation, invasion potential, and MMP-9 activity under hypoxia using a WST-1 assay, Matrigel invasion assay, and gelatin gel zymography, respectively.
The immunohistochemical expression of LCN2 was observed in the cytoplasm of EVTs, cytotrophoblasts and the decidua, but not in syncytiotrophoblasts. The addition of recombinant LCN2 did not affect proliferation, but enhanced the invasiveness (500 ng/mL, p < 0.01) and MMP-9 activity of primary cultured EVTs and JAR in a dose-dependent manner. Silencing LCN2 using shRNA reduced the invasiveness (p < 0.01) and MMP-9 activity of JAR. In addition, the hypoxic condition (2% O₂) increased LCN2 expression (p < 0.01), MMP-9 activity, and invasive ability (p < 0.01).
LCN2 was involved in the invasiveness of EVTs, especially under hypoxia, via increased MMP-9 activity.
滋养层细胞外突（EVTs）侵入早孕蜕膜和螺旋动脉是成功妊娠的关键步骤；然而，其机制尚不完全清楚。脂联素 2（LCN2）是一种多功能分泌蛋白，又称为中性粒细胞明胶酶相关脂质运载蛋白（NGAL），据报道，它可以通过激活基质金属蛋白酶-9（MMP-9）来增强几种癌细胞的侵袭性。在本研究中，分析了 LCN2 在早期胎盘组织中的表达和功能。
从行选择性终止妊娠的正常孕妇中获取 7 至 10 周妊娠的早期胎盘组织。使用免疫组化和 RT-PCR 检测 LCN2 的表达。从这些胎盘组织中分离出 EVTs 和绒毛膜癌细胞系（JAR），使用 WST-1 检测法、Matrigel 侵袭检测法和明胶凝胶酶谱分析法分别检测 LCN2 在缺氧条件下对增殖、侵袭潜能和 MMP-9 活性的影响。
LCN2 的免疫组化表达可见于 EVTs、滋养层细胞和蜕膜的细胞质中，但不在合体滋养层细胞中。添加重组 LCN2 不会影响增殖，但以剂量依赖性方式增强原代培养的 EVTs 和 JAR 的侵袭性（500ng/ml，p<0.01）和 MMP-9 活性。使用 shRNA 沉默 LCN2 可降低 JAR 的侵袭性（p<0.01）和 MMP-9 活性。此外，缺氧条件（2%O₂）增加了 LCN2 的表达（p<0.01）、MMP-9 活性和侵袭能力（p<0.01）。
LCN2 通过增加 MMP-9 活性参与 EVTs 的侵袭性，尤其是在缺氧条件下。
