Galectin-9: a new endometrial epithelial marker for the mid- and late-secretory and decidual phases in humans.
BACKGROUND
The galectin family has been reported to play a role in the regulation of cell growth, cell adhesion, apoptosis, inflammation, and immunomodulation, all of which are important for endometrial function, as well as implantation.


OBJECTIVE
The objective of the study was to investigate the expression and regulation of galectin-9, a beta-galactoside-binding lectin in the human endometrium.


METHODS
Galectin-9 mRNA and protein were analyzed in dated endometrial biopsies throughout the menstrual cycle and in human early-pregnancy decidua, as well as in the different endometrial cell compartments. Regulation of galectin-9 by estradiol, progesterone, epidermal growth factor, and interferon-gamma in endometrial epithelial cells in vitro was studied.


RESULTS
Galectin-9 mRNA analyzed by RNase protection assay is expressed in the human endometrium, specifically in the human endometrial epithelial cells but not in stromal or immune cells. It is expressed at very low concentrations during the proliferative phase and the early-secretory phase and shows a sharp and significant increase in the mid- and late-secretory phases, the window of implantation, as well as in the decidua. Accordingly, galectin-9 protein is also exclusively increased in human endometrial epithelial cells during the mid- and late-secretory phases and in the decidua, however, not in endometrial stromal cells or decidualized cells in vivo or in vitro. A regulation in vitro by estradiol, progesterone, epidermal growth factor, and interferon-gamma could not be detected.


CONCLUSIONS
Based on these findings and on the functional studies of other galectins, we suggest galectin-9 as a novel endometrial marker for the mid- and late-secretory and decidual phases.
Popovici
Roxana M
RM
Department of Gynecological Endocrinology and Reproductive Medicine, University of Heidelberg, Voss Strasse 9, 69115 Heidelberg, Germany. roxana.popovici@med.uni-heidelberg.de
Krause
Miriam S
MS
Germeyer
Ariane
A
Strowitzki
Thomas
T
von Wolff
Michael
M
D000328:Adult; D017209:Apoptosis; D015415:Biomarkers; D003656:Decidua / Q000378:metabolism*; D004717:Endometrium / Q000737:chemistry*; D005260:Female; D037161:Galectins / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000494:pharmacology; D008597:Menstrual Cycle / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis
D015415:Biomarkers; D037161:Galectins; C105032:LGALS9 protein, human; D012333:RNA, Messenger; D007371:Interferon-gamma