Shan N, Zhang X, Xiao X, Zhang H, Tong C, Luo X, Chen Y, Liu X, Yin N, Deng Q, Qi H
Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
Laboratory of Lipid and Glucose Research, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
Placenta. 2015 Aug;36(8):809-20. doi: 10.1016/j.placenta.2015.04.008. Epub 2015 May 21.
The laminin α4 subunit (LAMA4) has been shown to promote migration, proliferation, and survival of various cell types. This study investigated LAMA4's role in trophoblast cells during placental development.
LAMA4 expression was immunohistochemically assessed in the first trimester and term human placentas. LAMA4 siRNA was applied to silence LAMA4 expression in extravillous explants and HTR8/SVneo cells. Hypoxia-reoxygenation (H/R) conditions were applied to mimic preeclampsia. LAMA4 expression and trophoblast cell invasion, migration, and tube formation (a measure of angiogenesis) were assessed in HTR8/SVneo cells. The p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 was used to study the mechanism underlying LAMA4 activity. LAMA4 promoter methylation was assessed by bisulfite-sequencing polymerase chain reaction (PCR) or methylation-specific PCR.
LAMA4 levels in preeclamptic placentas were significantly lower than those in controls. LAMA4 silencing significantly inhibited extravillous explant outgrowth as well as HTR8/SVneo cell invasion and migration. H/R conditions significantly lowered LAMA4 expression. Application of either H/R conditions or LAMA4 silencing both significantly decreased HTR8/SVneo cell invasion, migration, and tube formation, decreased MMP2 and MMP9 expression, and increased TIMP2 expression. SB203580 significantly reduced LAMA4 expression. LAMA4 silencing significantly decreased p-p38, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal-regulated kinase (ERK) expressions; by contrast, H/R conditions induced significant upregulation of p-p38 and p-ERK but decreased p-JNK. LAMA4 promoter methylation was not significantly altered in preeclamptic placentas compared to controls.
LAMA4 expression is lowered in preeclamptic placentas and promotes trophoblast cell invasion, migration, and angiogenesis. H/R conditions decrease LAMA4 expression and appear to decouple the positive relationship between LAMA4 expression and p38 and ERK activation.
层粘连蛋白α4亚基（LAMA4）已被证明可促进多种细胞类型的迁移、增殖和存活。本研究调查了LAMA4在胎盘发育过程中对滋养层细胞的作用。
采用免疫组织化学方法评估早孕期和足月人胎盘组织中LAMA4的表达。应用LAMA4小干扰RNA（siRNA）沉默绒毛外植体和HTR8/SVneo细胞中LAMA4的表达。采用缺氧复氧（H/R）条件模拟子痫前期。评估HTR8/SVneo细胞中LAMA4的表达以及滋养层细胞的侵袭、迁移和管形成（血管生成的一种指标）。使用p38丝裂原活化蛋白激酶（MAPK）抑制剂SB203580研究LAMA4活性的潜在机制。通过亚硫酸氢盐测序聚合酶链反应（PCR）或甲基化特异性PCR评估LAMA4启动子甲基化情况。
子痫前期胎盘组织中LAMA4水平显著低于对照组。LAMA4沉默显著抑制绒毛外植体生长以及HTR8/SVneo细胞的侵袭和迁移。H/R条件显著降低LAMA4表达。施加H/R条件或沉默LAMA4均显著降低HTR8/SVneo细胞的侵袭、迁移和管形成，降低基质金属蛋白酶2（MMP2）和基质金属蛋白酶9（MMP9）的表达，并增加金属蛋白酶组织抑制因子2（TIMP2）的表达。SB203580显著降低LAMA4表达。LAMA4沉默显著降低磷酸化p38（p-p38）、磷酸化c-Jun氨基末端激酶（p-JNK）和磷酸化细胞外信号调节激酶（p-ERK）的表达；相比之下，H/R条件诱导p-p38和p-ERK显著上调，但降低p-JNK。与对照组相比，子痫前期胎盘组织中LAMA4启动子甲基化无显著变化。
子痫前期胎盘组织中LAMA4表达降低，其可促进滋养层细胞的侵袭、迁移和血管生成。H/R条件降低LAMA4表达，且似乎破坏了LAMA4表达与p38和ERK激活之间的正相关关系。
