Alterations in intracellular Ca2+ levels in human endometrial stromal cells after decidualization.

Calcium (Ca2+) is an important element for many physiological functions of the uterus, including embryo implantation. Here, we investigated the possible involvement of altered intracellular Ca2+ levels in decidualization in human endometrial stromal cells (hEMSCs). hEMSCs showed high levels of mesenchymal stem cell marker expression (CD73, CD90, and CD105) and did not express markers of hematopoietic progenitor cells (CD31, CD34, CD45, and HLA-DR). Decidualization is a process of ovarian steroid-induced endometrial stromal cell proliferation and differentiation. Several types of ion channels, which are regulated by the ovarian hormones progesterone and estradiol, as well as growth factors, are important for endometrial receptivity and embryo implantation. The combined application of progesterone (1 µM medroxyprogesterone acetate) and cyclic AMP (0.5 mM) for 6 days not only elevated inositol 1,4,5-triphosphate receptor (IP3R)-mediated Ca2+ release and IP3R expression, it also promoted ORAI and STIM expression as well as cyclopiazonic acid-induced Ca2+ release. Finally, intracellular Ca2+ levels and ion channel gene expression influenced hEMSC proliferation. These results suggest that cytosolic Ca2+ dynamics, mediated by specific ion channels, serve as an important step in the decidualization of hEMSCs.

Integrins expressed on the surface of human endometrial stromal cells derived from a female patient experiencing spontaneous abortion.

Here, as a basic study in revealing the correlation between extracellular matrix components and spontaneous abortion, we defined the types of integrins expressed on the surface of endometrial stromal (ES) cells retrieved from the uterus of a patient experiencing spontaneous abortion. For these, the types of integrin subunits in the ES cells retrieved from a woman with spontaneous abortion were identified at the transcriptional and translational levels, and functional assay was conducted for confirming the combinations of integrin α and ß subunits. Among the genes encoding 25 integrin subunits, significantly high transcription was seen in integrins α1, α2, α3, α4, α5, αV, ß1, ß3, and ß5. Translation of integrins α1, α3, α5, αV, and ß1 on the cell surface was detected in almost all ES cells, whereas integrins α2, α4, ß3, and ß4 were expressed translationally only in some ES cells. Subsequently, ES cells showed significantly increased adhesion to collagen I, laminin, fibronectin, and vitronectin, and functional blocking of integrin α1, α3, α5, and αV significantly inhibited adhesion to these molecules. These results demonstrated that active heterodimers composed of integrins α1ß1, α3ß1, α5ß1, and αVß1 were co-localized on the surface of ES cells derived from a patient experiencing spontaneous abortion.