No description available.

No description available.

No description available.

No description available.

The endometrium is a complex multicellular tissue that undergoes dynamic alterations under the control of ovarian-derived sex steroid hormones. During the proliferative phase of the human menstrual cycle, oestrogen induces proliferation of the endometrial epithelium while during the progesterone-dominated secretory phase, the endometrial stromal compartment differentiates in preparation for pregnancy. This differentiation event is termed decidualisation and it is accompanied by immune cell infiltration, vascular remodelling and secretion of cytokines and growth factors, as well as a newfound capacity of active steroid synthesis in the endometrium. Defective decidualisation has been described in several endometrial-associated disorders such as endometriosis, a pathology of ectopic endometrial tissue in the peritoneal cavity, often associated with infertility. Rodent models have been used for the investigation of endometrial physiology and pathology due to the similarity in uterine tissue architecture, appropriate endometrial responses to steroid hormones and the opportunity to inform cellular mechanisms using genetic manipulation. While the impact of 17β-oestradiol and progesterone on endometrial function have been extensively studied, androgens have only recently emerged as potent potential regulators of the endometrium, however, their impact on cell function has not been fully elucidated. The aims of this study were to: Identify the impact of androgens on endometrial function using a mouse model of steroid depletion (ovariectomy) followed by administration of the potent androgen dihydrotestosterone (DHT). Investigate the capacity of endometrial stromal cells to synthesise androgens during decidualisation using human primary endometrial stromal cells (hESCs) decidualised in vitro. Elucidate the decidualisation response of hESCs from women with endometriosis after modulation of androgen receptor (AR) function during decidualisation. Novel results obtained provided evidence of a role for androgens in inducing a trophic effect in the mouse uterus characterised by: pronounced endometrial epithelial proliferation, altered expression pattern of AR, changes in the expression of genes involved in cell-cycle progression and stromal-epithelial cross-talk. In addition, androgen treatment resulted in a striking and unexpected increase in the number of endometrial glands. Decidualisation of hESCs resulted in time-dependent changes in expression of the androgen synthesising enzymes AKR1C3 and 5α-reductase (accompanied by biosynthesis of both testosterone and DHT in a dynamic time-dependent manner). Notably, blocking of AR action arising from local androgen signalling during decidualisation of hESCs culminates in sub-optimal decidualisation as detected by the expression of the classical decidualisation markers IGFBP1 and PRL. Women with endometriosis are reported to exhibit defective decidualisation, which may be accompanied with infertility. Treatment of hESCs from women with endometriosis with an AR agonist (DHT) or antagonist (flutamide) during decidualisation resulted in striking differences in decidualisation response as demonstrated in a case-study approach. Taken together, these findings highlight novel roles of androgens in regulating endometrial function by impacting on cell proliferation, gland formation and decidualisation. These striking new findings have implications for endometrial disorders such as endometriosis. Future studies will focus on the use of selective androgen receptor modulators, a novel class of compounds, with tissue-selective actions and without the undesired side-effects of potent androgens. The use of AR modulators would benefit from a personalised medicine approach, instructed by patient profiling to direct therapeutic targeting of endometrial disorders.

No description available.

archives@tulane.edu / Androgen excess predisposes females to type 2 diabetes. Using mouse models, our lab reported that androgen excess causes insulin resistance via activation of the androgen receptor (AR) in the brain. Neurons of the arcuate nucleus of the hypothalamus (ARC) regulate hepatic glucose production (HGP). Thus, I hypothesized that in female mice, androgen excess in neurons of the ARC causes hepatic insulin resistance by increasing HGP. To test this, I injected AaV-Cre-GFP or AaV-GFP into the ARC of ARlox/lox female mice to generate ARC-specific AR knockout (ARC-ARKO) and control mice, respectively. When exposed to a Western diet, control female mice chronically treated with dihydrotestosterone (DHT) developed insulin resistance and fasting hyperglycemia compared to vehicle-treated control mice. In contrast, DHT-treated ARC-ARKO mice remained insulin sensitive and normoglycemic compared to vehicle-treated ARC-ARKO mice. During a hyperinsulinemic-euglycemic clamp, insulin’s ability to suppress HGP was blunted in DHT-treated control mice. In contrast, insulin was still able to suppress HGP in DHT-treated ARC-ARKO females. Additionally, during the clamp, DHT-treated control mice showed no alteration in hepatic activation of AKT, a marker of hepatocyte insulin sensitivity, but exhibited reduced activation of hepatic STAT3, a marker of hypothalamic insulin sensitivity. In contrast, in DHT-treated ARC-ARKO mice activation of hepatic STAT3 was increased. In a parallel study, estradiol treatment improved insulin sensitivity in control ovariectomized (OVX) mice. In contrast, in DHT-treated OVX mice, estradiol treatment did not improve insulin sensitivity. Together these results suggest that in female mice exposed to a Western diet, androgen excess causes hypothalamic estrogen resistance and insulin resistance in ARC neurons via action at the AR leading to impairments in the brain-IL6-pSTAT3 pathway which results in unsuppressed HGP. / 1 / Jamie Morford

Thesis (Ph.D.), Memorial University of Newfoundland, 2000. / Bibliography: leaves 109-124.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 87-114).

Src signaling plays an important role in prostate cancer (PrCa) progression. It has previously been shown that Src interacts with androgen receptor (AR) and enhances AR transactivation. Although it has been shown that Src promotes AR activity, the underlying pathway has not been defined. To help characterize the Src-AR pathway, the cellular localizations of Src, p-Src, AR, pAR, and Prostate Specific Antigen (PSA, an AR target gene) were analyzed in androgen-dependent (AD) LNCaP cells and in androgen-independent (AI) castration-resistant C4-2B cells. Using sub-cellular fractionation, the data showed that treatment of AD cells with synthetic androgen R1881 increased p-Src, AR, pAR, and PSA in the nucleus, while the levels of c-Src remained unchanged. Treatment of AI cells with R1881 increased pSrc and AR in the nucleus, while the levels of c-Src and PSA remained unchanged. When using immunofluorescence microscopy, R1881 did not appear to increase the nuclear levels of p-Src or c-Src, so perhaps this technique is not as sensitive or quantitative as subcellular fractionation immunoblots. The presence of PSA in the nucleus was unexpected given its well proven role as a secreted protein. Nuclear PSA was observed upon androgen stimulation in AD and AI cells, and in the nucleus of AI cells upon androgen deprivation. Given PSA's ability to induce cell division and decrease apoptosis when transfected into cells, its presence in the nucleus may imply that PSA acts there to help induce tumorigenesis. The effect of Src on AR activity was further studied by transfection of a dominant negative src (SrcK298M) in AD and AI cells. Transfection with SrcK298M did not affect PSA expression in LNCaP cells, but strongly inhibited PSA levels in AI cells. Integrin signaling through Src was investigated in PrCa by ligand binding assay in AD and AI cells. The data showed that alpha v beta 3 integrin (but not alpha v beta 6) upon attachment to fibronectin or TGF-beta-latency associated peptide (TGF- beta-LAP) increases p-Src levels in AD and AI cells, while the levels of c-Src, PSA, and AKT remain unchanged. Thus, alpha v beta 3 integrin facilitates Src signaling, but the activation does not appear to affect AR transactivation. In conclusion, these data show that Src is required for AR activity and, consequently, PSA expression in AI prostate cancer cells, but not in AD cells. These data also suggest that the nuclear co-localization of p-Src, AR and PSA might allow macromolecular interactions, which can further enhance AR transactivation and promote disease progression. With respect to the switch in tumor progression from an AD to AI state, the data indicate that the integrin-Src pathway does not include AKT or PSA (and not AR by deduction), so perhaps other non-AR pathways help facilitate tumor growth at the AI state.