The immunoglobulin-like, transmembrane Advanced Glycation End product (AGE) Receptor (RAGE) is a pattern recognition receptor implicated in the transduction of pro-inflammatory signalling and processes. Over the past decade a substantial body of evidence has accrued implicating RAGE in the pathogenesis of several chronic inflammatory and vascular diseases such as diabetes, rheumatoid arthritis, amyloidosis, atherosclerosis and renal failure. More recently RAGE has been linked to cancer progression, possibly through its role in the inflammatory process. AGE products have been shown to exert their intracellular effects through ligation of their cognate receptor RAGE and the subsequent transactivation of NFKB signalling in several cellular contexts. Polycystic Ovary Syndrome (PCOS) is a reproductive endocrine disorder characterized by hyperandrogenism, chronic anovulation and insulin resistance, thus increasing the risk of diabetes mellitus in these patients. Non-enzymatically glycated AGEs are formed at an accelerated rate and accumulate in tissues in conditions of high glucose and oxidative stress. Interestingly, young normoglycemic women with PCOS exhibit higher serum AGE levels and increased RAGE expression in poly-cystic ovaries. RAGE is also regulated through the activity of the estrogen receptor (ER). The natural cyclical expression of estrogen throughout the menstrual cycle is perturbed in endometriosis even post menopause, suggesting that RAGE could also be dysregulated. Finally PCOS has been implicated in increased risk to endometrial cancer progression as has uterine exposure to the selective estrogen receptor modulator Tamoxifen (TX) therefore it is plausible that RAGE has a function in this disease. Objectives: The principal aims of this thesis were to characterise RAGE expression for the first time in fertile and infertile endometriotic and PCO human endometrium, and to initiate RAGE characterisation in endometrium obtained from patients with endometrial hyperplasia and cancer. Secondly, this thesis endeavoured to elucidate the transcriptional mechanisms regulating RAGE in vitro response to 17beta-estradiol and AGEs which are elevated in endometriosis and PCOS pathology respectively, and in endometrial cancer. Methodology: This project employed the use of real time Polymerase Chain Reaction (RT-PCR), Chromatin Immunoprecipitation (ChIP), Immunohistochemistry (IHC) and western blotting (WB). Results: Immunohistochemistry and RT-PCR data revealed that basal RAGE expression was significantly greater in PCO and endometriotic endometrium when compared to fertile controls, and significantly elevated in two cancer patients. RAGE was also characterised in endometrial cell models in which it was shown to be modulated at the mRNA and protein level by AGE-HSA, 17beta-estradiol (E2) and its antagonist 4-hydroxytamoxifen. Moreover, we have shown that RAGE is modulated by two distinct pathways through the estrogen receptor (ER) and NFKB. Novel ChIP results confirmed the presence of p65 and ER-alpha on the RAGE promoter at non- classical Spl and Apl sites in response to AGEs, E2 and TX. Conclusions: The results in this thesis may implicate endometrial RAGE expression in the infertility evident in women with PCOS and endometriosis. Furthermore, recent evidence implicates RAGE in mediating inflammation-driven tumourigenesis. Thus, over-expression of endometrial RAGE in PCOS and endometriosis, and in patients receiving tamoxifen for breast cancer treatment may predispose these women to an elevated risk of cancer.

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Endometriosis is an estrogen-dependent disease that is characterized by the growth of endometrial tissue outside of the uterine cavity. The most common endometriotic lesions are ovarian endometrioma, peritoneal lesions, and deeply-infiltrating endometriosis. Ten percent of women in reproductive age are affected, a gross underestimate due to the delay in diagnosis and non-specific symptoms. The etiology of endometriosis is not well understood, making diagnosis difficult, and treatments suboptimal. Currently, laparoscopic surgery is the gold standard for diagnosis, however this method is invasive, costly, and physicians are often reluctant to send their patients to surgery without certainty of disease. It is therefore a research priority to identify a minimally-invasive biomarker for endometriosis. Over the years, the search for a biomarker has shifted from a single circulating biomarker, to a panel of circulating biomarkers, and finally to the advent of newer technologies. The studies of proteomics, genomics, phenomics, and metabolomics have shown some promise thus far. MicroRNAs, a discovery of genomics, are short, non-coding RNA strands that regulate mRNA expression by silencing or degrading the transcript. The dysregulation of miRNAs have been shown to contribute to the pathology of many gynecological conditions, and have shown to be dysregulated in endometriosis. To date however, results have been underwhelming due to differences in methodologies and failure to consider endometriosis as a heterogeneous disease. Three miRNAs were studied based on their prevalence in the literature (miR-9, -21, and -424), and three others (miR-10a, -10b, and -204) were measured based on their association with BDNF. In the current study, miR-204 expression was significantly lower (p=0.0016) in the eutopic endometrium of women with endometriosis compared to controls. Relative expression of miR-21, miR-424, and miR-10b differed significantly (p<0.05) across lesion types in women with exclusively endometriomas, peritoneal or deep-infiltrating lesions. Corresponding BDNF expression in the lesion types were inversely correlated to miRNA expression suggesting these miRNA regulate BDNF and are implicated in endometriosis pathology. Due to the findings that miRNAs are differentially expressed between endometriotic lesions, this study also suggests that, different lesion types are biochemically distinct. / Thesis / Master of Health Sciences (MSc)

published_or_final_version / abstract / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / toc / Pathology / Master / Master of Philosophy

Call number: LD2668 .T4 1965 L334 / Master of Science

The human endometrium is a dynamic, multi-cellular tissue that lines the inside of the uterine cavity. During a woman’s reproductive lifespan the endometrium is subjected to cyclical episodes of proliferation, angiogenesis, differentiation/decidualisation, shedding (menstruation), repair and regeneration in response to fluctuating levels of oestrogen and progesterone secreted by the ovaries. The endometrium displays unparalleled, tightly regulated, tissue remodelling resulting in a healed, scar-free tissue following menses or parturition. Mechanisms responsible for initiation of menses have been well documented: following progesterone withdrawal there is an increase in inflammatory mediators, focal hypoxia and induction and activation of matrix-degrading enzymes. In contrast, the molecular and cellular changes responsible for rapid, regulated, tissue repair at a time when oestrogen and progesterone are low are poorly understood. Histological studies using human menstrual phase endometrium have revealed that tissue destruction and shedding occur in close proximity to re-epithelialisation/repair. It has been proposed that re-epithelialisation involves proliferation of glandular epithelial cells in the remaining basal compartment; there is also evidence for a contribution from the underlying stroma. A role for androgens in the regulation of apoptosis of endometrial stromal cells has been proposed but the impact of androgens on tissue repair has not been investigated. Studies using human xenografts and primates have been used to model some aspects of the impact of progesterone withdrawal but simultaneous shedding (menses) and repair have not been modelled in mice; the species of choice for translational biomedical research. In the course of the studies described in this thesis, the following aims have been addressed: 1. To establish a model of menses in the mouse which mimics menses in women, namely; simultaneous breakdown and repair, overt menstruation, immune cell influx, tissue necrosis and re-epithelialisation. 2. To use this model to determine if the stromal cell compartment contributes to endometrial repair. 3. To examine the impact of androgens on the regulation of menses (shedding) and repair. An informative mouse model of endometrial breakdown that was characterised by overt menses, as well as rapid repair, was developed. Immunohistological evidence for extensive tissue remodelling including active angiogenesis, transient hypoxia, epithelial cell-specific proliferation and re-epithelialisation were obtained by examining uterine tissues recovered during an “early window of breakdown and repair” (4 to 24 hours after progesterone withdrawal). Novel data included identification of stromal cells that expressed epithelial cell markers, close to the luminal surface following endometrial shedding, suggesting a role for mesenchymal to epithelial transition (MET) in re-epithelialisation of the endometrium. In support of this idea, array and qRTPCR analyses revealed dynamic changes in expression of mRNAs encoded by genes known to be involved in MET during the window of breakdown and repair. Roles for hypoxia and tissue-resident macrophages in breakdown and tissue remodelling were identified. Treatment of mice with dihydrotestosterone to mimic concentrations of androgens circulated in women at the time of menses had an impact on the timing and duration of endometrial breakdown. Array analysis revealed altered expression of genes implicated in MET and angiogenesis/inflammation highlighting a potential, previously unrecognised role for androgens in regulation of tissue turnover during menstruation. In summary, using a newly refined mouse model new insights were obtained, implicating androgens and stromal MET in restoration of endometrial tissue homeostasis during menstruation. These findings may inform development of new treatments for disorders associated with aberrant repair such as heavy menstrual bleeding and endometriosis.

No description available.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences