Placental expression of aminopeptidase-Q (laeverin) and its role in the pathophysiology of preeclampsia

Mona Nystad; Vasilis Sitras; Merethe Larsen; Ganesh Acharya

doi:10.1016/j.ajog.2014.06.047

Placental expression of aminopeptidase-Q (laeverin) and its role in the pathophysiology of preeclampsia

Am J Obstet Gynecol. 2014 Dec;211(6):686.e1-31. doi: 10.1016/j.ajog.2014.06.047. Epub 2014 Jun 21.

Authors

Mona Nystad¹, Vasilis Sitras², Merethe Larsen³, Ganesh Acharya⁴

Affiliations

¹ Department of Clinical Medicine, Women's Health and Perinatology Research Group, Faculty of Health Sciences, University of Tromsø, Norway; Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway. Electronic address: mona.nystad@unn.no.
² Department of Clinical Medicine, Women's Health and Perinatology Research Group, Faculty of Health Sciences, University of Tromsø, Norway; Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway; Department of Obstetrics, Oslo University Hospital-Rikshospitalet, Oslo, Norway.
³ Department of Occupational and Environmental Medicine, University Hospital of North Norway, Tromsø, Norway.
⁴ Department of Clinical Medicine, Women's Health and Perinatology Research Group, Faculty of Health Sciences, University of Tromsø, Norway; Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway; Department of Clinical Sciences, Intervention, and Technology, Karolinska Institute, Stockholm, Sweden.

PMID: 24959655
DOI: 10.1016/j.ajog.2014.06.047

Abstract

Objective: The purpose of this study was to investigate the expression and subcellular localization of laeverin, a placenta-specific membrane-bound aminopeptidase, in preeclamptic placentas and its role in trophoblast cell migration and invasion.

Study design: Expression of laeverin was investigated in 6 normal and 6 preeclamptic placentas with the use of immunofluorescence, sodium dodecylsulfate-polyacrylamide gel electrophoresis with Western blot analysis and immunoelectron microscopy. The role of laeverin in trophoblast migration and invasion was studied with the use of the xCelligence system and Boyden chambers with Matrigel in HTR-8/SVneo cells. The effect of laeverin gene-silencing on selected genes that are involved in cell transformation and tumorigenesis was evaluated by polymerase chain reaction array. The Student t test, Mann-Whitney U test, χ(2) test, or F-test was used to compare groups as appropriate.

Results: Laeverin was expressed in the cell membrane of villous trophoblasts in third-trimester healthy placentas; in preeclamptic placentas, it was expressed ectopically in the cytoplasm, especially in microvesicles. Immunoelectron microscopy showed laeverin leakage into the fetal capillaries and abundant expression in microvesicles in preeclamptic placentas. Migration and invasion of HTR-8/SVneo cells were reduced by 11.5% (P = .023) and 56.7% (P = .001), respectively, by laeverin gene-silencing. Analysis of downstream pathways affected by laeverin-silencing demonstrated significant down-regulation of integrin A2 (39-fold), integrin B3 (5-fold), and matrix metalloprotease 1 (36-fold).

Conclusion: Expression of laeverin protein is altered in preeclamptic placentas. Its ectopic expression in the cytoplasm and microvesicles, rather than the cell membrane and leakage into the fetal capillaries, may have a role in the pathophysiologic condition of preeclampsia. Laeverin gene appears to be involved in trophoblast cell migration and invasion through interaction with integrins and matrix metalloprotease 1.

Keywords: aminopeptidase; laeverin; microvesicle; placenta; preeclampsia.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Case-Control Studies
Cell Line
Cell Membrane / metabolism
Cell Movement*
Cytoplasm / metabolism
Cytoplasmic Vesicles / metabolism
Down-Regulation
Female
Gene Knockdown Techniques
Humans
Integrin alpha2 / genetics
Integrin beta3 / genetics
Matrix Metalloproteinase 1 / genetics
Metalloproteases / genetics
Metalloproteases / metabolism*
Placenta / metabolism*
Pre-Eclampsia / metabolism*
Pre-Eclampsia / pathology
Pregnancy
RNA, Small Interfering
Reverse Transcriptase Polymerase Chain Reaction
Trophoblasts / metabolism*

Substances

Integrin alpha2
Integrin beta3
RNA, Small Interfering
LVRN protein, human
Metalloproteases
MMP1 protein, human
Matrix Metalloproteinase 1