Endometrial osteopontin, a ligand of beta3-integrin, is maximally expressed around the time of the "implantation window".
OBJECTIVE
To analyze endometrial mRNA and protein expression of osteopontin and its receptor, beta3-integrin, throughout the menstrual cycle.


METHODS
Study by immunohistochemistry, RNase protection assay, and ELISA.


METHODS
Academic research unit.


METHODS
Forty-five regularly cycling women without endometrial pathology.


METHODS
Expression of endometrial osteopontin and beta3-integrin mRNA was analyzed by RNase protection assay in endometrium, endometrial epithelial cells, stromal cells, and endometrial leukocytes (CD45) and by immunohistochemistry in frozen sections of endometrium throughout the menstrual cycle. Concentration of osteopontin was studied in uterine secretions by ELISA.


METHODS
mRNA and protein expression of osteopontin and beta3-integrin.


RESULTS
Osteopontin mRNA and protein was weakly expressed in the proliferative phase and maximally expressed in the mid to late secretory phases in endometrium, endometrial epithelial cells, and endometrial leukocytes and in uterine secretions. Beta3-integrin mRNA and protein were expressed in stromal cells throughout the menstrual cycle and were maximally expressed in epithelial cells in the mid to late secretory phases.


CONCLUSIONS
Expression of osteopontin and its receptor, beta3-integrin, in human endometrial glands and osteopontin secretion into the uterine cavity around the time of the "implantation window" suggest a role for these proteins in endometrial function and implantation.
von Wolff
M
M
Department of Obstetrics and Gynecology, Ludwig Maximilians University-Grosshaden, Munich, Germany. Michael.von.Wolff@med.uni-heidelberg.de
Strowitzki
T
T
Becker
V
V
Zepf
C
C
Tabibzadeh
S
S
Thaler
C J
CJ
D000328:Adult; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D010064:Embryo Implantation / Q000502:physiology*; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D006801:Humans; D039661:Integrin beta3; D008597:Menstrual Cycle / Q000378:metabolism; D008875:Middle Aged; D053495:Osteopontin; D010980:Platelet Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*; D014599:Uterus / Q000378:metabolism
D015703:Antigens, CD; D039661:Integrin beta3; D010980:Platelet Membrane Glycoproteins; D012333:RNA, Messenger; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin