Stomatin-like Protein-2 Promotes Aggregation, Colonization and Migration of Endometriotic Cells.

Endometriosis is a chronic gynecological disease in women of childbearing age, which leads to infertility with risk of endometrial and ovarian cancer. The pathogenesis of endometriosis is poorly understood, and cure/treatment for it is not available, except for symptomatic treatment. The recurrence rate of endometriosis is high. SLP-2 is an inner mitochondrial membrane protein whose participation has been explained in cases of endometrial stromal cell growth, differentiation and migration, but its role in endometriosis is yet to be understood. Previous studies have found altered expression of stomatin-like protein 2 (SLP-2) in the serum of endometriotic patients. Therefore, we have studied the possible role of SLP-2 in the development of endometriosis. We found the ubiquitous and high expression of SLP-2 in the endometriotic tissue of both human endometriosis patients and rat endometriosis model. SLP-2 is seen in the glandular epithelial cells and stromal cells in the eutopic/normal or non-endometriosis group endometrium from human subjects. Finding high expression levels of SLP-2 in endometriotic tissue and ovarian cystic cells derived from endometriosis patients, we explored the possible role of SLP-2 in the cell aggregation, colonization, migration, and invasion in the human endometriotic cells associated with the progression of the endometriosis. Transient silencing of SLP-2 by its siRNA hinders endometriotic cells, aggregation, migration, and invasion into the extracellular matrix, which confirms SLP-2 involvement in endometriotic disease onset and progression. This study unravels the ubiquitous expression of SLP-2 in the human ectopic endometrial tissue and its role in the endometriotic cell migration, colonization, aggregation, and invasion leading to endometriosis progression.

Sorcin is involved during embryo implantation via activating VEGF/PI3K/Akt pathway in mice.

Our earlier studies have demonstrated the cyclic variation and also the altered expression of sorcin in endometrium during early-to-mid-secretory phase transition in women with unexplained infertility. The current study was undertaken to establish the functional role of sorcin in endometrial receptivity in mice. Results indicated that sorcin was highly expressed during the window of implantation in mice and functional blockage of sorcin caused significant reduction in number of implanted blastocyst. The receptivity markers (i.e.Integrin ß3, HBEGF, IGFBP1, WNT4 and Cyclin E)) were found to be downregulated in sorcin knocked down uterine horn on day 5 as compared to untreated horn. The reduced attachment and expansion of BeWo spheroids on RL95-2 endometrial cells with sorcin knock down, in in vitro model of endometrium-trophoblast interaction further supported these findings. Uterine sorcin expression pattern during estrous cycle and in delayed implantation mice model suggested the upregulation of sorcin by estrogen. The functional blockade of sorcin induced the intracellular Ca+2 levels in endometrial epithelial cells (EECs), which indicated that altered Ca+2 homeostasis might be responsible for implantation failure. Sorcin silencing led to significant reduction in the expression of angiogenic factor VEGF and its downstream effector molecules i.e. PI3K, Akt and NOS. The migratory and invasive properties of HUVECs were abrogated by anti-VEGF or by adding culture media from sorcin blocked EECs, which indicated that sorcin might mediate angiogenesis during implantation. Taken together, sorcin is involved in the regulation of Ca+2-mediated angiogenesis via VEGF/PI3K/Akt pathway in endometrial cells and plays a crucial role in preparing the endometrium for implantation.

The regulation of Hh/Gli1 signaling cascade involves Gsk3ß- mediated mechanism in estrogen-derived endometrial hyperplasia.

The present study was undertaken to explore the functional involvement of Hh signaling and its regulatory mechanism in endometrial hyperplasia. Differential expression of Hh signaling molecules i.e., Ihh, Shh, Gli1 or Gsk3ß was observed in endometrial hyperplasial (EH) cells as compared to normal endometrial cells. Estradiol induced the expression of Hh signaling molecules and attenuated the expression of Gsk3ß whereas anti-estrogen (K1) or progestin (MPA) suppressed these effects in EH cells. Cyclopamine treatment or Gli1 siRNA knockdown suppressed the growth of EH cells and reduced the expression of proliferative markers. Estradiol also induced the nuclear translocation of Gli1 which was suppressed by both MPA and K1 in EH cells. While exploring non-canonical mechanism, LY-294002 (Gsk3ß activator) caused a decrease in Gli1 expression indicating the involvement of Gsk3ß in Gli1 regulation. Further, Gsk3ß silencing promoted the expression and nuclear translocation of Gli1 demonstrating that Gsk3ß serves as a negative kinase regulator of Gli1 in EH cells. Similar attenuation of Hh signaling molecules was observed in rats with uterine hyperplasia undergoing anti-estrogen treatment. The study suggested that Hh/Gli1 cascade (canonical pathway) as well as Gsk3ß-Gli1 crosstalk (non-canonical pathway) play crucial role in estrogen-dependent cell proliferation in endometrial hyperplasia.