Endometrial TIMP-4 mRNA is expressed in the stroma, while TIMP-4 protein accumulates in the epithelium and is released to the uterine fluid.
We have previously reported that endometrial mRNA expression of both tissue inhibitors of metalloproteinase-4 (TIMP-4) and matrix metalloproteinase-26 (MMP-26) peaks in the early secretory phase, which implies a role in implantation. The objective of this study was to compare the distribution of TIMP-4 and MMP-26 in endometrial tissue and uterine fluid over the menstrual cycle. Endometrial tissue was analysed with in situ hybridization and immunohistochemistry to localize mRNA and protein for TIMP-4 and MMP-26 in the same set of samples. TIMP-4 mRNA was quantified in separated stromal and epithelial cells using real-time PCR. Uterine fluid was analysed with western blotting. TIMP-4 mRNA was exclusively localized to the stroma, whereas MMP-26 mRNA was expressed by epithelial cells. TIMP-4 protein was only occasionally found in the stroma but was consistently present in granules of the apical part of luminal and glandular epithelial cells. TIMP-4, but not MMP-26, was demonstrated in uterine fluid. Thus, TIMP-4 is produced in the stroma only, secreted by stromal cells, taken up by epithelial cells, accumulated in apical granules and finally secreted to the uterine fluid. Maximal expression of MMP-26, and its strongest inhibitor TIMP-4, in the early and mid-secretory phase suggests a role during implantation. MMP-26 is stored in epithelial cells in its active form, is not released spontaneously and is controlled by TIMP-4 in both stroma and uterine fluid.
Pilka
R
R
Department of Obstetrics and Gynecology, University Hospital, SE-221 84 Lund, Sweden.
Noskova
V
V
Domanski
H
H
Andersson
C
C
Hansson
S
S
Casslén
B
B
D000328:Adult; D000368:Aged; D015153:Blotting, Western / Q000379:methods; D010064:Embryo Implantation; D004717:Endometrium / Q000166:cytology / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D020782:Matrix Metalloproteinases / Q000378:metabolism* / Q000652:urine; D053505:Matrix Metalloproteinases, Secreted; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000378:metabolism*; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics* / Q000378:metabolism / Q000652:urine; D014599:Uterus / Q000378:metabolism; D000097792:Tissue Inhibitor of Metalloproteinase-4
D020782:Matrix Metalloproteinases; D053505:Matrix Metalloproteinases, Secreted; D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4; C410599:MMP26 protein, human