title: Laminin α4 (LAMA4) expression promotes trophoblast cell invasion, migration, and angiogenesis, and is lowered in preeclamptic placentas.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: N
authors.initials: N
authors.lastname: Shan
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Laboratory of Lipid and Glucose Research, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: X
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: C
authors.initials: C
authors.lastname: Tong
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: N
authors.initials: N
authors.lastname: Yin
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Deng
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China. Electronic address: qihongbocq@gmail.com.
authors.forename: H
authors.initials: H
authors.lastname: Qi
mesh_terms: D002465:Cell Movement / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D006801:Humans; D007797:Laminin / Q000235:genetics* / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000235:genetics*; D010920:Placenta / Q000378:metabolism* / Q000473:pathology; D011225:Pre-Eclampsia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000235:genetics; D014327:Trophoblasts / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation
chemical_list: C501369:LAMA4 protein, human; D007797:Laminin; D034741:RNA, Small Interfering
keywords: ERK; JNK; LAMA4; Laminin; MAPK; Methylation; Placenta; Preeclampsia; Trophoblast; p38