Estrogen receptor-alpha (ER-alpha) and defects in uterine receptivity in women

Endometriosis is a disorder that affects 5% of the normal population but is present in up to 40% of women with pelvic pain and/or infertility. Recent evidence suggests that the endometrium of women with endometriosis exhibits progesterone insensitivity. One endometrial protein that fluctuates in response to progesterone is the estrogen receptor-alpha (ER alpha), being down-regulated at the time of peak progesterone secretion during the window of implantation. Here we demonstrate that the biomarker of uterine receptivity, beta 3 integrin subunit, is reduced or absent in some women with endometriosis and that such defects are accompanied by inappropriate over-expression of ER alpha during the mid-secretory phase. Using a well-differentiated endometrial cell line we showed that the beta 3 integrin protein is negatively regulated by estrogen and positively regulated by epidermal growth factor (EGF). By competing against estrogen with various selective estrogen receptor modulators (SERMs) and estrogen receptor agonists and antagonists, inhibition of expression of the beta 3 integrin by estrogen can be mitigated. In conclusion, we hypothesize that certain types of uterine receptivity defects may be caused by the loss of appropriate ER alpha down-regulation in the mid-secretory phase, leading to defects in uterine receptivity. Such changes might be effectively treated by timely administration of the appropriate anti-estrogens to artificially block ER alpha and restore normal patterns of gene expression. Such treatments will require further clinical studies

The RhoA Guanine Nucleotide Exchange Factor, LARG, Mediates ICAM-1-Dependent Mechanotransduction In Endothelial Cells To Stimulate Transendothelial Migration

RhoA-mediated cytoskeletal rearrangements in endothelial cells (ECs) play an active role in leukocyte transendothelial cell migration (TEM), a normal physiological process in which leukocytes cross the endothelium to enter the underlying tissue. While much has been learned about RhoA signaling pathways downstream from ICAM-1 in ECs, little is known about the consequences of the tractional forces that leukocytes generate on ECs as they migrate over the surface before TEM. We have found that after applying mechanical forces to ICAM-1 clusters, there is an increase in cellular stiffening and enhanced RhoA signaling compared to ICAM-1 clustering alone. We have identified that the Rho GEF LARG/ARHGEF12 acts downstream of clustered ICAM-1 to increase RhoA activity and that this pathway is further enhanced by mechanical force on ICAM-1. Depletion of LARG decreases leukocyte crawling and inhibits TEM. This is the first report of endothelial LARG regulating leukocyte behavior and EC stiffening in response to tractional forces generated by leukocytes.Doctor of Philosoph

cAMP-Response Element-Binding 3-Like Protein 1 (CREB3L1) is Required for Decidualization and its Expression is Decreased in Women with Endometriosis

Endometriosis is a major cause of infertility and pelvic pain, affecting more than 10% of reproductive-aged women. Progesterone resistance has been observed in the endometrium of women with this disease, as evidenced by alterations in progesterone-responsive gene and protein expression. cAMP-Response Element-Binding 3-like protein 1 (Creb3l1) has previously been identified as a progesterone receptor (PR) target gene in mouse uterus via high density DNA microarray analysis. However, CREB3L1 function has not been studied in the context of endometriosis and uterine biology. In this study, we validated progesterone (P4) regulation of Creb3l1 in the uteri of wild-type and progesterone receptor knockout (PRKO) mice. Furthermore, we observed that CREB3L1 expression was significantly higher in secretory phase human endometrium compared to proliferative phase and that CREB3L1 expression was significantly decreased in the endometrium of women with endometriosis. Lastly, by transfecting CREB3L1 siRNA into cultured human endometrial stromal cells (hESCs) prior to hormonal induction of in vitro decidualization, we showed that CREB3L1 is required for the decidualization process. Interestingly, phosphorylation of ERK1/2, critical factor for decidualization, was also significantly reduced in CREB3L1-silenced hESCs. It is known that hESCs from patients with endometriosis show impaired decidualization and that dysregulation of the P4-PR signaling axis is linked to a variety of endometrial diseases including infertility and endometriosis. Therefore, these results suggest that CREB3L1 is required for decidualization in mice and humans and may be linked to the pathogenesis of endometriosis in a P4-dependent manner

Design and Synthesis of Novel pH-Sensitive Anticancer Drug and Efflux Pump Inhibitor Conjugates

Resistance to anti-cancer therapies has proven a challenge for effective treatments. Efflux pumps when overexpressed in cancer cells, eject drugs from the cell, rendering them ineffective. The pH of cancer cells is generally lower than that of normal cells, due to their raised metabolic rate. This disparity can be exploited using a prodrug that is activated at an acidic pH, resulting in improved efficacy for treatments. Co-administration of an efflux pump inhibitor (EPI) with an anticancer drug can prevent drug efflux, reduce normal cell cytotoxicity, and improve the efficacy. Using the cytotoxic drug, doxorubicin, the EPIs, MC70 and norverapamil with the cis¬-aconityl linker, possible conjugates were modelled. We chose the cis-aconityl linker because it is acid-labile at pH values <7 and, is suitable for targeted release of doxorubicin in tumours. Linker conjugates for glucosamine and 4-aminotetrahydropyran, model compounds for doxorubicin, 4-phenylphenol, the model compound for MC70, and dibutylamine, phenethylamine and N-methyl-phenethylamine, model compounds for norverapamil, were synthesized and analysed. This study has laid the groundwork for a novel way of increasing the efficacy of doxorubicin, and possibly other medicine, which will hopefully lead to more studies and eventual treatments and therapies

Embryo Implantation

A lesson learned from modern developmental biology is the striking degree of conservation of strategies and molecules used to program developmental events in species as diverse as insects, birds, amphibians, and mammals. Nonetheless, mammals retain distinctions with regard to the strategies used to protect and nourish their offspring during development, namely the processes of implantation and placentation. While involving relatively few cell types, placentation is a complex process. Furthermore, genes associated with this process display remarkably high spontaneous mutational rates, suggesting a strong adaptive/selection pressure on this tissue (Roberts et al., 1999). In the case of implantation, a highly coordinated process is set into motion hereby specialized cells of the embryo, the trophectoderm and trophoblast, establish contact with a specialized tissue of the mother, the uterus. The exquisite coordination involves the regulated production of growth factors, cytokines, and hormones by embryonic as well as maternal tissues of both uterine and extrauterine origins. In concert, complementary receptors for these factors must be expressed by the appropriate tissues to propagate implantation signals. In addition, cell surface components must become functionally available to support attachment of trophectoderm/trophoblast and uterine cells. To add to the challenge, it has been shown that, in most mammals, there is only a restricted time during the uterine cycle during which implantation can occur (Psychoyos, 1986). Failure to initiate the critical early events of implantation during this “window of receptivity” results in early pregnancy failure

A smart fishing suite

A range of cell phone applications, known as mFisheries, improves market connections, supply chain efficiency and safety at sea for small-scale fishers in Trinidad and Tobago

Regulation of RhoA Activity by Adhesion Molecules and Mechanotransduction

The low molecular weight GTP-binding protein RhoA regulates many cellular events, including cell migration, organization of the cytoskeleton, cell adhesion, progress through the cell cycle and gene expression. Physical forces influence these cellular processes in part by regulating RhoA activity through mechanotransduction of cell adhesion molecules (e.g. integrins, cadherins, Ig superfamily molecules). RhoA activity is regulated by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) that are themselves regulated by many different signaling pathways. Significantly, the engagement of many cell adhesion molecules can affect RhoA activity in both positive and negative ways. In this brief review, we consider how RhoA activity is regulated downstream from cell adhesion molecules and mechanical force. Finally, we highlight the importance of mechanotransduction signaling to RhoA in normal cell biology as well as in certain pathological states

Progesterone Function in Human Endometrium: Clinical Perspectives

Progesterone is essential for endometrial receptivity and successful establishment of pregnancy. Either an insufficient progesterone concentration or an insufficient response to progesterone, therefore can lead to infertility and pregnancy loss. Assessment of the role that either progesterone insufficiency or inadequate progesterone response plays in human reproductive failure has been difficult to assess because serum progesterone concentrations fluctuate markedly, limiting the ability to characterize sufficiency of progesterone, and there are no highly reliable markers of endometrial function available. Recent evidence demonstrates exquisite sensitivity of normal endometrium to very low levels of progesterone stimulation, suggesting that progesterone insufficiency should not be a common cause of reproductive failure. Further evidence suggests that women with endometriosis, and possibly polycystic ovarian syndrome, have an altered progesterone response, which may explain some of the clinical features of these disorders and supports the hypothesis that progesterone resistance underlies some cases of human reproductive failure

Immune-inflammation gene signatures in endometriosis patients

To determine if the molecular profiles of endometriotic lesions contain informative measures of inflammation and immune dysfunction that may contribute to better understanding of the interplay between immune dysfunction and inflammation and their contribution to endometriosis pathogenesis

Protein Inhibitor of Activated STAT3 (PIAS3) Is Down-Regulated in Eutopic Endometrium of Women with Endometriosis

Endometriosis is a major cause of chronic pelvic pain and infertility. Activation of STAT3 appears central to the inflammatory phenotype of eutopic endometrium in women with endometriosis. However, the molecular mechanism by which this occurs remains unknown. Our objective is to determine how STAT3 activity is regulated in endometriosis. Protein inhibitor of activated STAT3 (PIAS3) is a negative regulator of STAT3 activity. We examined the levels of PIAS3 in endometrium from women with and without endometriosis using Western blot analysis and immunohistochemistry. Levels of PIAS3 are significantly lower, in contrast with phosphorylation of STAT3, in women with endometriosis compared to women without endometriosis. Furthermore, induction of endometriosis in the baboon showed a significant reduction of PIAS3 expression during the progression of the disease. Interferon-γ (INFγ) reduces PIAS3 protein levels and increases phospho-STAT3 levels through CXCL10 in endometrial cells, Ishikawa, and 12Z cells. These results suggest that attenuation of PIAS3 causes aberrant activation of STAT3 in endometriosis, leading to inflammatory changes that may impair fertility or cause pain