Expression of P450 aromatase and 17beta-hydroxysteroid dehydrogenase type 1 at fetal-maternal interface during tubal pregnancy.
Steroidogenesis in the placenta has been studied widely, but little is known about steroid metabolism in ectopic pregnancy. Previous studies have indicated that trophoblast invasion and placentation in the uterus and the fallopian tube may be controlled by similar mechanisms. As far as 17beta-estradiol (E(2)) production is concerned, it has been well demonstrated that its biosynthesis in the placenta involves the action of P450 aromatase (P450arom) and 17beta-hydroxysteroid dehydrogenase type 1 (17HSD1). The purpose of this study was to characterize the expression pattern of P450arom and 17HSD1 at the fetal-maternal interface, particularly in various trophoblast cells, in tubal pregnancy. Using in situ hybridization, P450arom mRNA was localized in syncytiotrophoblast (ST) cells, which are mainly responsible for hormone production during pregnancy, whereas no signal was detected in villous cytotrophoblast (VCT), column CT and extravillous CT (EVCT) cells. Immunohistochemical assays revealed that 17HSD1 is present in ST cells, a large portion of EVCT cells and 20% of column CT cells. On the other hand, no expression of 17HSD1 was detected in VCT cells. In addition, 17HSD1 was found in epithelial cells of the fallopian tube. Interestingly, the expression level of 17HSD1 in fallopian tube epithelium during tubal pregnancy was significantly higher than that during normal cycle. Our data provide the first evidence that normal and tubal pregnancies possess identical expression of P450arom and 17HSD1 in ST cells and therefore, similar E(2) production in the placenta. Further, the association of 17HSD1 with EVCT cells indicates that 17HSD1 perhaps play a role in trophoblast invasion. Finally, increased expression of 17HSD1 in epithelial cells of fallopian tube may lead to a local E(2) supply sufficient for the maintenance of tubal pregnancy.
Li
Yan
Y
Biocenter Oulu and Research Center for Molecular Endocrinology, WHO Collaborating Centre, University of Oulu, FIN-90014 Oulu, Finland.
Qin
Li
L
Xiao
Zhi-Jie
ZJ
Wang
Yan-Ling
YL
Herva
Riitta
R
Leng
Jin-Hua
JH
Lang
Jing-He
JH
Isomaa
Veli
V
Piao
Yun-Shang
YS
D015067:17-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis*; D000328:Adult; D001141:Aromatase / Q000096:biosynthesis*; D005187:Fallopian Tubes / Q000201:enzymology; D005260:Female; D005498:Follicular Phase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008183:Luteal Phase / Q000378:metabolism; D010920:Placenta / Q000166:cytology / Q000201:enzymology*; D011247:Pregnancy; D011274:Pregnancy, Tubal / Q000201:enzymology* / Q000503:physiopathology; D012333:RNA, Messenger / Q000096:biosynthesis
D012333:RNA, Messenger; D015067:17-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase; D001141:Aromatase