Claudin 7 is reduced in uterine epithelial cells during early pregnancy in the rat
- First Online:
The non-receptive uterine luminal epithelium forms an intact polarised epithelial barrier that is refractory to blastocyst invasion. During implantation, organised dismantling of this barrier leads to a receptive state promoting blastocyst attachment. Claudins are tight junction proteins that increase in the uterine epithelium at the time of implantation. Claudin 7 is a member of this family but demonstrates a basolateral localisation pattern that is distinct from other claudins. The present study investigated the localisation, abundance and hormonal regulation of claudin 7 to elucidate a role for the protein during implantation. The results showed that claudin 7 demonstrates a distinct basal and lateral localisation in the uterine luminal and glandular epithelium throughout early pregnancy. On day 1, claudin 7 is abundantly present in response to ovarian estrogen. At the time of implantation, claudin 7 decreases in abundance. This decrease is not dependent on blastocyst presence, as shown by results in pseudopregnant animals. We propose that claudin 7 mediates intercellular adhesions in the uterine epithelium and also may be responsible for stabilising adhesion proteins at the basolateral cell surface. Thus, claudin 7 may function under the maintenance of the uterine luminal epithelial barrier, in the non-receptive state preventing implantation from occurring.
KeywordsRat Hormones Ovariectomy Uterus Pseudopregnancy
- Kaneko Y, Lecce L, Day ML, Murphy CR (2011) Beta(1) and beta(3) integrins disassemble from basal focal adhesions and beta(3) integrin is later localised to the apical plasma membrane of rat uterine luminal epithelial cells at the time of implantation. Reprod Fertil Dev 23:481–495PubMedCrossRefGoogle Scholar
- Psychoyos A (1976) Hormonal control of uterine receptivity for nidation. J Reprod Fertil Suppl 25:17–28Google Scholar