title: Nuclear progesterone receptor A and B isoforms in mouse fallopian tube and uterus: implications for expression, regulation, and cellular function.
abstract: Progesterone and its interaction with nuclear progesterone receptors (PR) PR-A and PR-B play a critical role in the regulation of female reproductive function in all mammals. However, our knowledge of the regulation and possible cellular function of PR protein isoforms in the fallopian tube and uterus in vivo is still very limited. In the present study, we revealed that equine chorionic gonadotropin (eCG) treatment resulted in a time-dependent increase in expression of both isoforms, reaching a maximal level at 48 h in the fallopian tube. Regulation of PR-A protein expression paralleled that of PR-B protein expression. However, in the uterus PR-B protein levels increased and peaked earlier than PR-A protein levels after eCG treatment. With prolonged exposure to eCG, PR-B protein levels decreased, whereas PR-A protein levels continued to increase. Furthermore, subsequent treatment with human (h)CG decreased the levels of PR protein isoforms in both tissues in parallel with increased endogenous serum progesterone levels. To further elucidate whether progesterone regulates PR protein isoforms, we demonstrated that a time-dependent treatment with progesterone (P(4)) decreased the expression of PR protein isoforms in both tissues, whereas decreases in p27, cyclin D(2), and proliferating cell nuclear antigen protein levels were observed only in the uterus. To define the potential PR-mediated effects on apoptosis, we demonstrated that the PR antagonist treatment increased the levels of PR protein isoforms, induced mitochondrial-associated apoptosis, and decreased in epidermal growth factor (EGF) and EGF receptor protein expression in both tissues. Interestingly, immunohistochemistry indicated that the induction of apoptosis by PR antagonists was predominant in the epithelium, whereas increase in PR protein expression was observed in stromal cells of both tissues. Taken together, these observations suggest that 1) the tissue-specific and hormonal regulation of PR isoform expression in mouse fallopian tube and uterus, where they are potentially involved in regulation of mitochondrial-mediated apoptosis depending on the cellular compartment; and 2) a possible interaction between functional PR protein and growth factor signaling may have a coordinated role for regulating apoptotic process in both tissues in vivo.
authors.affiliation: Section of Endocrinology, Dept. of Physiology and Pharmacology, Sahlgrenska Academy, Göteborg University, SE-40530, Gothenburg, Sweden. ruijin.shao@fysiologi.gu.se
authors.forename: Ruijin
authors.initials: R
authors.lastname: Shao
authors.forename: Birgitta
authors.initials: B
authors.lastname: Weijdegård
authors.forename: Karin
authors.initials: K
authors.lastname: Ljungström
authors.forename: Anders
authors.initials: A
authors.lastname: Friberg
authors.forename: Changlian
authors.initials: C
authors.lastname: Zhu
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Wang
authors.forename: Yihong
authors.initials: Y
authors.lastname: Zhu
authors.forename: Julia
authors.initials: J
authors.lastname: Fernandez-Rodriguez
authors.forename: Emil
authors.initials: E
authors.lastname: Egecioglu
authors.forename: Emilia
authors.initials: E
authors.lastname: Rung
authors.forename: Håkan
authors.initials: H
authors.lastname: Billig
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D006063:Chorionic Gonadotropin / Q000502:physiology; D004815:Epidermal Growth Factor / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D004958:Estradiol / Q000097:blood; D004963:Estrenes / Q000494:pharmacology; D005187:Fallopian Tubes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005663:Furans / Q000494:pharmacology; D005786:Gene Expression Regulation; D006727:Hormone Antagonists / Q000494:pharmacology; D006736:Horses; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D015735:Mifepristone / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D011374:Progesterone / Q000097:blood / Q000494:pharmacology; D011980:Receptors, Progesterone / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology*; D014599:Uterus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
chemical_list: D006063:Chorionic Gonadotropin; D004963:Estrenes; D005663:Furans; D006727:Hormone Antagonists; D011980:Receptors, Progesterone; C101118:progesterone receptor A; C097314:progesterone receptor B; C076196:Org 31710; D015735:Mifepristone; D011374:Progesterone; D004958:Estradiol; D004815:Epidermal Growth Factor; D066246:ErbB Receptors