241. Changes in the expression of Annexin IV mRNA and protein in human endometrium
A. P. Ponnampalam A and P. A. W. Rogers AMonash University Obstetrics and Gynaecology, Centre for Women’s Health Research, Clayton, VIC, Australia
Reproduction, Fertility and Development 17(9) 95-95 https://doi.org/10.1071/SRB05Abs241
Submitted: 26 July 2005 Accepted: 26 July 2005 Published: 5 September 2005
Abstract
In a previous study investigating global gene expression throughout the menstrual cycle,1 Annexin 4 (ANXIV) was identified as having significant cyclic changes in human endometrium. ANXIV belongs to a ubiquitous family of Ca2+-dependent phospholipid and membrane-binding proteins. The aims of this study were to investigate the cellular localization and regulation of ANXIV mRNA and temporal expression of ANXIV protein in human endometrium during the menstrual cycle.
mRNA Expression: The menstrual cycle was divided into seven stages by histological evaluation. Curettings of endometrium were collected from 60 cycling women. For cellular localization, tissues from eight endometrial curettings were dissociated with collagenase into single cells, separated into epithelial and stromal cell fractions and snap frozen. Total RNA was extracted and ANXIV mRNA was quantified by real-time PCR.
Immunohistochemistry: Full thickness endometrial tissue was collected from 50 reproductive age women undergoing hysterectomy. Tissue sections were formalin-fixed and paraffin-embedded. Goat polyclonal ANXIV antibody was used to localize ANXIV protein.
ANXIV mRNA was significantly upregulated in the whole tissue during mid-late secretory phase of the cycle, and was predominantly expressed in epithelial cells. ANXIV protein was detected in the luminal and glandular epithelium in high levels throughout the menstrual cycle except in early secretory (ES) phase. The intensity of immunostaining was stronger in the glands of the basalis compared to functionalis in early proliferative phase, however, by the late secretory phase the functionalis glands showed higher expression levels.
ANXIV mRNA data are consistent with a role for progesterone in upregulating the expression of ANXIV, although protein levels remain high through menstruation and into the proliferative phase. ANXIV can indirectly inhibit prostaglandin production, which is important for implantation. Hence the low levels of ANXIV protein at ES phase may relate to processes involved in implantation.
(1) Ponnampalam et al. (2004). Mol. Hum. Reprod. 10(12), 879–893.
