Regulation der Progesteron-Rezeptor-Isoformen A und B im humanen Endometrium und ihr Einfluss auf spezifische Zielgene (Amphiregulin und Calcitonin)

Introduction: The progesterone receptor (PR) is expressed in two different isoforms A and B. The sequence of both isoforms is identical, however, the longer isoform PR-B has an additional chain of amino acids at its N-terminus, therefore, also their molecular weight differs (PR- A= 94 kDa, PR- B= 114 kDa). Expression and localization of both isoforms throughout the human menstrual cycle were investigated. In addition, the expression of amphiregulin and calcitonin, two candidate markers which are regulated by the PR A isoform in the mouse model, were studied throughout the menstrual cycle. Material & Methods: An antibody specific for PR-B (Ab-6) and an antibody specific for PR-A (Ab-7) as well as an antibody against both isoforms (Ab-8, all Neomarkers) were used for immunofluorescence and Western Blots. The human endometrial samples were obtained at different days of the cycle from women undergoing hysterectomy. They had a regular cycle and were not recently treated with hormones. In order to investigate the differences in expression and localization of the two isoforms within the same tissue section, dual immunonfluorescence staining was performed. The PR-A and PR-B specific antibodies were linked to two different fluorochromes and pictures were taken for the specific wavelengths. By using a special software (Axiovision, Zeiss) both pictures were put together in an overlay technique allowing the identification of colocalization and differential expression of the PR isoforms within single cells. For Western Blot analysis the tissue samples were separated in stromal and epithelial cells. The samples were homogenized and the separated proteins electroblotted and detected by the specific antibodies. Amphiregulin and Calcitonin were detected with immunohistochemistry, PCR and Western Blot. Results: Both PR-A and PR-B were detected throughout the cycle by immunofluorescence and Western blotting. Immunofluorescence studies revealed a strong expression of both PR-A and PR-B in the proliferative phase in both glands and stroma. However, in the late secretory phase, staining strongly decreases in the glands, with the abscence of PR-A in the glands, whereas the stroma remains positive for PR-A and to a lesser extent also PR-B. Western Blot analysis showed expression of both isoforms for proliferative endometrium samples and expression of PR-A only during late secretory phase endometrium. Amphiregulin and calcitonin were both detected, but were not regulated by progesterone in human endometrium. Discussion & conclusion: PR-A and PR-B are regulated differentially throughout the human menstrual cycle. Both isoforms are co-expressed during the proliferative phase, but their expression differs in the mid to late secretory phase. During this phase, as the expression of PR decreases in the glands, PR-A remains strong in the stroma, which might indicate its importance for progesterone-dependent signaling after ovulation. The role of PR-B might lie in glandular function. These results might contribute to the understanding of the distinct pathways of progesterone action and function.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2005

Author dc:creator

• Rebhan, Stephanie

Contributors dc:contributor

• Claßen-Linke, Irmgard

• info:eu-repo/classification/ddc/610
• Medizin
• Progesteronrezeptor
• Endometrium

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121989%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:60266