Pemphigoid gestationis autoantigen, transmembrane collagen XVII, promotes the migration of cytotrophoblastic cells of placenta and is a structural component of fetal membranes.
In pemphigoid gestationis (PG), autoantibodies target collagen XVII, a hemidesmosomal transmembrane protein, which is an important element in cutaneous epithelial adhesion and signalling. We report that collagen XVII is expressed in the first trimester and term syncytial and cytotrophoblastic cells of normal placenta and in epithelial cells of amniotic membrane. Immunoelectron microscopy confirmed the localization of collagen XVII to the hemidesmosomes of amniotic epithelium. Examination of three PG placentas showed mild villitis, but there were no differences between collagen XVII expression levels or immunostaining signals as compared to normal placenta. Collagen XVII expression was also detected in cultured extravillous trophoblast HTR-8/SVneo cells, where collagen XVII expression was upregulated by PMA and TGF-beta1. Interestingly, the presence of Col15, the cell migration domain of collagen XVII, induced the migration of HTR-8/SVneo cells in transmigration assay. Analysis of amniotic fluid samples at different gestational weeks revealed that a large quantity of collagen XVII ectodomain was shed into amniotic fluid throughout pregnancy. Biochemical and immunoblotting analysis indicated that the ectodomain in amniotic fluid is structurally very similar to the ectodomain produced by cultured keratinocytes. Cultured cells from amniotic fluid samples also expressed collagen XVII. Our results suggest that collagen XVII may contribute to the invasion of extravillous trophoblasts during placental development and is also required for the integrity of amniotic basement membrane. Although the exact pathomechanism of PG is still largely unknown, the clinical symptoms of PG are initiated after the expression of collagen XVII in placenta during the first trimester of pregnancy.
Huilaja
Laura
L
Department of Dermatology, University of Oulu and Clinical Research Center, Oulu University Hospital, Oulu, Finland.
Hurskainen
Tiina
T
Autio-Harmainen
Helena
H
Hofmann
Silke C
SC
Sormunen
Raija
R
Räsänen
Juha
J
Ilves
Mika
M
Franzke
Claus-Werner
CW
Bruckner-Tuderman
Leena
L
Tasanen
Kaisa
K
D000328:Adult; D000650:Amnion / Q000378:metabolism; D001324:Autoantigens / Q000737:chemistry*; D001485:Basement Membrane / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D024041:Non-Fibrillar Collagens / Q000737:chemistry*; D006559:Pemphigoid Gestationis / Q000276:immunology* / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D014327:Trophoblasts / Q000378:metabolism*; D000097805:Collagen Type XVII
D001324:Autoantigens; D024041:Non-Fibrillar Collagens; D000097805:Collagen Type XVII