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Burchall GF, Pouniotis DS, Teede HJ, Ranasinha S, Walters KA, Piva TJ. Expression of the plasminogen system in the physiological mouse ovary and in the pathological polycystic ovary syndrome (PCOS) state. Reprod Biol Endocrinol 2019; 17:33. [PMID: 30878040 PMCID: PMC6420749 DOI: 10.1186/s12958-019-0472-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 02/25/2019] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The fibrinolytic system and its inhibitors play a number of roles, apart from their function in blood haemostasis and thrombosis, namely in ovarian folliculogenesis and in ovulation. Plasminogen is converted to active plasmin at the time of follicular rupture through a decrease in plasminogen activator inhibitor-1 (PAI-1) and an increase in plasminogen activators. Oligo-/anovulation and follicle arrest are key characteristics of PCOS, but studies evaluating fibrinolytic/proteolytic markers within human or animal PCOS ovaries are lacking. We aimed to investigate and compare the expression and distribution of the plasminogen system markers in PCOS and control ovaries. METHODS A hyperandrogenised PCOS mouse model was used that mimics the ovarian, endocrine and metabolic features of the human condition. Immunohistochemistry and digital image analysis were used to investigate and compare fibrinolytic/proteolytic markers plasminogen, plasminogen/plasmin, tissue plasminogen activator, urokinase plasminogen activator and inhibitor PAI-1 in PCOS and control ovaries. Student's t-test was used to compare data sets for normally distributed data and Wilcoxon-Mann Whitney test for non-normally distributed data. RESULTS We noted differences in the ovarian distribution of PAI-1 that was expressed throughout the PCOS ovary, unlike the peripheral distribution observed in control ovaries. Plasminogen was present in small follicles only in PCOS ovaries but not in small follicles of control ovaries. When we assessed and compared PAI-1 expression within follicles of different developmental stages we also noted significant differences for both the PCOS and control ovaries. While we noted differences in distribution and expression within specific ovarian structures, no differences were noted in the overall ovarian expression of markers assessed between acyclical PCOS mice and control mice at the diestrus stage of the estrous cycle. CONCLUSIONS Our novel study, that comprehensively assessed the fibrinolytic/proteolytic system in the mouse ovary, showed the expression, differential localisation and a potential role for the plasminogen system in the physiological mouse ovary and in PCOS. Androgens may be involved in regulating expression of the ovarian plasminogen system. Further studies evaluating these markers at different time-points of ovulation may help to further clarify both physiological and potential pathological actions these markers play in ovulatory processes distorted in PCOS.
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Tarulli GA, Laven-Law G, Shehata M, Walters KA, Denis IM, Rahman MM, Handelsman DJ, Dean NR, Tilley WD, Hickey TE. Androgen Receptor Signalling Promotes a Luminal Phenotype in Mammary Epithelial Cells. J Mammary Gland Biol Neoplasia 2019; 24:99-108. [PMID: 30099649 DOI: 10.1007/s10911-018-9406-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 07/18/2018] [Indexed: 01/11/2023] Open
Abstract
Androgens influence mammary gland development but the specific role of the androgen receptor (AR) in mammary function is largely unknown. We identified cell subsets that express AR in vivo and determined the effect of AR activation and transgenic AR inhibition on sub-populations of the normal mouse mammary epithelium by flow cytometry and immunohistochemistry. Immunolocalisation of AR with markers of lineage identity was also performed in human breast tissues. AR activation in vivo significantly decreased the proportion of basal cells, and caused an accumulation of cells that expressed a basal cell marker but exhibited morphological features of luminal identity. Conversely, in AR null mice the proportion of basal mammary epithelial cells was significantly increased. Inhibition of AR increased basal but not luminal progenitor cell activity in vitro. A small population of AR-positive cells in a basal-to-luminal phenotype transition was also evident in human breast lobules. Collectively, these data support a role for AR in promoting a luminal phenotype in mammary epithelial cells.
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Bertoldo MJ, Caldwell ASL, Riepsamen AH, Lin D, Gonzalez MB, Robker RL, Ledger WL, Gilchrist RB, Handelsman DJ, Walters KA. A Hyperandrogenic Environment Causes Intrinsic Defects That Are Detrimental to Follicular Dynamics in a PCOS Mouse Model. Endocrinology 2019; 160:699-715. [PMID: 30657917 DOI: 10.1210/en.2018-00966] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 01/10/2019] [Indexed: 02/06/2023]
Abstract
Polycystic ovary syndrome (PCOS) is a common cause of female infertility. Hyperandrogenism is both a major symptom and key diagnostic trait of PCOS; however, the direct impact of this androgen excess on ovarian dynamics is unclear. By combining a DHT-induced PCOS mouse model with an ex vivo follicle culture system, we investigated the impact of hyperandrogenism on ovarian function. Ovaries from PCOS mice exhibited the characteristic polycystic ovary morphology with numerous large cystic follicles and no corpora lutea present. Isolation and individual culture of preantral and antral follicles from PCOS mice resulted in slower growth rates during 5 days compared with the follicles isolated from control mice (P < 0.01). In contrast, preovulatory follicles from PCOS mice exhibited a significant increase in growth rate compared with controls (P < 0.01). Preantral follicles from PCOS ovaries maintained comparable follicular health as control follicles, but antral and preovulatory PCOS follicles exhibited reduced follicle health (P < 0.01) and survival rates (P < 0.01). Compared with controls, PCOS females also exhibited a poorer response to hyperstimulation (P < 0.01), impaired oocyte function evident by increased levels of reactive oxygen species (P < 0.01), and a reduction in on-time embryo development (P < 0.01). These results demonstrate that prolonged exposure to androgen excess leads to aberrant follicle development, which persists even after removal from the hyperandrogenic environment, causing perturbed follicular developmental trajectories. These findings indicate that an in vivo hyperandrogenic environment in patients with PCOS may intrinsically induce detrimental effects on follicles and oocytes.
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Walters KA, Gilchrist RB, Ledger WL, Teede HJ, Handelsman DJ, Campbell RE. New Perspectives on the Pathogenesis of PCOS: Neuroendocrine Origins. Trends Endocrinol Metab 2018; 29:841-852. [PMID: 30195991 DOI: 10.1016/j.tem.2018.08.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 11/25/2022]
Abstract
Polycystic ovary syndrome (PCOS) is the most common endocrine condition in reproductive-aged women. It is characterized by reproductive, endocrine, metabolic, and psychological features. The cause of PCOS is unknown, thus there is no cure and its management remains suboptimal because it relies on the ad hoc empirical management of symptoms only. We review here the strong support for PCOS having a neuroendocrine origin. In particular, we focus on the role of aberrant hypothalamic-pituitary function and associated hyperandrogenism, and their role as major drivers of the mechanisms underpinning the development of PCOS. This important information now provides a target site and a potential mechanism for the future development of novel, targeted, and mechanism-based effective therapies for the treatment of PCOS.
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Walters KA, Eid S, Edwards MC, Thuis-Watson R, Desai R, Bowman M, Marren AJ, Handelsman DJ. Steroid profiles by liquid chromatography-mass spectrometry of matched serum and single dominant ovarian follicular fluid from women undergoing IVF. Reprod Biomed Online 2018; 38:30-37. [PMID: 30527851 DOI: 10.1016/j.rbmo.2018.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 10/19/2018] [Accepted: 10/23/2018] [Indexed: 10/27/2022]
Abstract
RESEARCH QUESTION Can IVF outcomes be predicted from the steroid profile generated by liquid chromatography-mass spectrometry (LC-MS/MS) from follicular fluid collected from a single dominant follicle and serum after ovarian stimulation. DESIGN Prospective observational cohort study in which serum and follicular fluid were collected from women and used to generate steroid profiles by LC-MS/MS. A total of 93 consecutive women enrolled for IVF treatment were recruited at the Fertility Unit, Royal Prince Alfred Women and Babies Hospital, Sydney between September 2014 and July 2015. Baseline and serum levels at oocyte retrieval, as well as follicular fluid samples from the largest single antral follicle, were collected. All samples underwent steroid analysis within a single batch to measure progesterone (P4), oestradiol (E2), oestrone (E1), dehydroepiandrosterone (DHEA), androstenedione (A4), testosterone (T), dihydrotestosterone (DHT), and 3 α, 5α androstanediol (3α-diol) and 3β, 5α androstanediol (3β-diol). RESULTS P4, E2, E1, A4, T, DHEA and A4 were detectable in all baseline serum levels, at oocyte retrieval and in follicular fluid samples, whereas DHT, 3α-diol and 3β-diol were only detectable in a minority of samples. The most consistent predictor of pre-transfer (number of follicles >14mm in diameter, oocytes retrieved or fertilized, day-5 blastocysts) outcomes was baseline serum anti-Müllerian hormone. In follicular fluid, E2 was a negative predictor of the number of oocytes retrieved and the number of day-5 blastocysts but no follicular fluid steroids predicted pregnancy outcome. CONCLUSIONS None of the nine steroids measured in follicular fluid predicted pregnancy outcome in women undergoing IVF.
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Walters KA, Bertoldo MJ, Handelsman DJ. Evidence from animal models on the pathogenesis of PCOS. Best Pract Res Clin Endocrinol Metab 2018; 32:271-281. [PMID: 29779581 DOI: 10.1016/j.beem.2018.03.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Polycystic ovarian syndrome (PCOS) is the most common endocrine condition in women, and is characterized by reproductive, endocrine and metabolic features. However, there is no simple unequivocal diagnostic test for PCOS, its etiology remains unknown and there is no cure. Hence, the management of PCOS is suboptimal as it relies on the ad hoc empirical management of its symptoms only. Decisive studies are required to unravel the origins of PCOS, but due to ethical and logistical reasons these are not possible in humans. Experimental animal models for PCOS have been established which have enhanced our understanding of the mechanisms underlying PCOS and propose novel mechanism-based therapies to treat the condition. This review examines the findings from various animal models to reveal the current knowledge of the mechanisms underpinning the development of PCOS, and also provides insights into the implications from these studies for improved clinical management of this disorder.
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Bertoldo MJ, Uddin GM, Youngson NA, Agapiou D, Walters KA, Sinclair DA, Morris MJ, Gilchrist RB. Multigenerational obesity-induced perturbations in oocyte-secreted factor signalling can be ameliorated by exercise and nicotinamide mononucleotide. Hum Reprod Open 2018; 2018:hoy010. [PMID: 30895251 PMCID: PMC6276682 DOI: 10.1093/hropen/hoy010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/05/2018] [Accepted: 05/03/2018] [Indexed: 12/13/2022] Open
Abstract
STUDY QUESTION Can maternal and offspring high-fat diet (HFD)-induced changes in mRNA expression levels in mice be ameliorated by interventions in female offspring? SUMMARY ANSWER Our results indicate that exercise and nicotinamide mononucleotide (NMN) can ameliorate the negative effects of maternal and post-weaning HFD in female offspring. WHAT IS KNOWN ALREADY Maternal and post-weaning HFD can perturb offspring developmental trajectories. As rates of maternal obesity are rising globally, there is a need for effective treatments in offspring to ameliorate the negative effects from a maternal obesogenic environment. Modulation of the nicotinamide adenine dinucleotide (NAD+) pathway by exercise and the NAD+ precursor NMN has previously been shown to reduce the effects of obesity. STUDY DESIGN SIZE DURATION This study consisted of a multigenerational study using C57Bl6 mice. Mice were fed a control (chow) or HFD ad libitum throughout mating, pregnancy and lactation (n = 13-25). Female offspring (n = 72) were then also supplied either a chow or HFD post-weaning. At 9 weeks of age offspring from HFD dams were subjected to exercise on a treadmill for 9 weeks or at 16 weeks of age administered NMN (i.p.) for 2.5 weeks. At 18.5 weeks mice were euthanized and ovaries and cumulus-oocyte complexes (COC) were collected to examine the possibility of ameliorating the negative effects of maternal and post-weaning HFD. PARTICIPANTS/MATERIALS SETTING METHODS Ovary and COC mRNA expression was analysed using RT-qPCR. An initial screen of candidate genes was developed to test which molecular pathways may be involved in generating adverse reproductive system effects. For histological analysis, ovarian tissue was fixed in paraformaldehyde and embedded in paraffin and stained with haematoxylin and eosin. The numbers of primordial, primary, secondary and antral follicles were counted. MAIN RESULTS AND THE ROLE OF CHANCE In the offspring's COC, maternal obesity increased both growth differentiation factor 9 (Gdf9: 2-fold; P < 0.05, HFD versus chow) and bone morphogenetic protein 15 (Bmp15: 4-fold; P < 0.05, HFD versus chow) mRNA expression levels while exercise and NMN interventions did not regulate Gdf9 and Bmp15 in the same manner. In whole ovary, maternal diet programmed a 25-50% reduction in FSH receptor and sirtuin-3 mRNA expression levels in daughter ovaries (P < 0.05, HFD versus chow). There was a significant interaction between HFD and intervention on the proportion of large preantral and preovulatory follicles (P < 0.05). However, the increase in preovulatory follicles did not translate to increased oocyte yield. NMN administration resulted in reduced body weight in HFD-fed individuals. LIMITATIONS REASONS FOR CAUTION It is unclear if the changes in oocyte mRNA expression levels reported here will impact oocyte quality and fertility in offspring. Offspring ovulation rate or fecundity could not be studied here and fertility trials are required to determine if the changes in gene expression do reduce fertility. WIDER IMPLICATIONS OF THE FINDINGS Our results demonstrate that maternal and offspring HFD perturbs key signalling pathways that are known to regulate fertility in mice, highlighting the importance of interventions in helping to prevent the declining rates of fertility in the context of the current obesity epidemic. STUDY FUNDING/COMPETING INTERESTS This work was supported by grants and fellowships from the National Health and Medical Research Council to R.B.G. (APP1023210, APP1062762, APP1117538) and to M.J.M. and D.A.S. (APP1044295). DAS is a consultant to and inventor on patents licenced to Ovascience, Metrobiotech and GlaxoSmithKline. The other authors declare that there is no conflict of interest.
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Walters KA, Handelsman DJ. Role of androgens in the ovary. Mol Cell Endocrinol 2018; 465:36-47. [PMID: 28687450 DOI: 10.1016/j.mce.2017.06.026] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/28/2017] [Accepted: 06/30/2017] [Indexed: 11/18/2022]
Abstract
It has been well established for decades that androgens, namely testosterone (T) plays an important role in female reproductive physiology as the precursor for oestradiol (E2). However, in the last decade a direct role for androgens, acting via the androgen receptor (AR), in female reproductive function has been confirmed. Deciphering the specific roles of androgens in ovarian function has been hindered as complete androgen resistant females cannot be generated by natural breeding. In addition, androgens can be converted into estrogens which has caused confusion when interpreting findings from pharmacological studies, as observed effects could have been mediated via the AR or estrogen receptor. The creation and analysis of genetic mouse models with global and cell-specific disruption of the Ar gene, the sole mediator of pure androgenic action, has now allowed the elucidation of a role for AR-mediated androgen actions in the regulation of normal and pathological ovarian function. This review aims to summarize findings from clinical, animal, pharmacological and novel genetic AR mouse models to provide an understanding of the important roles androgens play in the ovary, as well as providing insights into the human implications of these roles.
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Upton DH, Walters KA, McTavish KJ, Holt J, Handelsman DJ, Allan CM. Reproductive failure in mice expressing transgenic follicle-stimulating hormone is not caused by loss of oocyte quality. Biol Reprod 2018; 98:491-500. [PMID: 29365049 DOI: 10.1093/biolre/ioy015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/21/2018] [Indexed: 12/30/2022] Open
Abstract
Human female reproductive aging features declining ovarian follicle reserve and oocyte quality, and rising levels of circulating follicle-stimulating hormone (FSH). We determined the effects of elevated FSH on oocyte-embryo development in mature mice exhibiting premature infertility caused by progressively rising transgenic human FSH (TgFSH) levels. Oocyte-embryo developmental competence and quality were examined using oocyte maturation and aneuploidy rates, biomarkers of oocyte quality, and reciprocal embryo transfers assessed for implantation and pregnancy. In vitro maturation suggested that TgFSH exposure only hindered oocyte developmental competence in old females, as significantly more oocytes from ≥12-month-old TgFSH females remained at germinal vesicle stage compared with age-matched control oocytes. Aneuploidy rates were equivalent in oocytes from aging TgFSH compared with wildtype females. Cumulus cell expression levels of candidate biomarker Inhba, Egfr, and Rgs2 transcripts were elevated in associated aneuploid vs euploid oocytes from both TgFSH and wildtype females. In vivo, embryos transferred from subfertile 6-month-old TgFSH females to wildtype recipients yielded normal implantation rates and more pups born compared with controls. Transfer of wildtype embryos rescued the fertility of 6-month-old TgFSH-recipient females, although pup birth weight was reduced in TgFSH vs wildtype recipients. Our current findings show that elevated FSH had minimal disruption of either embryo developmental capacity or uterine function when examined in isolation, and the subfertility of TgFSH female mice was not caused by altered oocyte aneuploidy or quality.
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Camlin NJ, Jarnicki AG, Vanders RL, Walters KA, Hansbro PM, McLaughlin EA, Holt JE. Grandmaternal smoke exposure reduces female fertility in a murine model, with great-grandmaternal smoke exposure unlikely to have an effect. Hum Reprod 2018; 32:1270-1281. [PMID: 28402417 DOI: 10.1093/humrep/dex073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/28/2017] [Indexed: 01/22/2023] Open
Abstract
STUDY QUESTION What effect does multigenerational (F2) and transgenerational (F3) cigarette smoke exposure have on female fertility in mice? SUMMARY ANSWER Cigarette smoking has a multigenerational effect on female fertility. WHAT IS KNOWN ALREADY It has been well established that cigarette smoking decreases female fertility. Furthermore, a growing body of evidence suggests that smoking during pregnancy decreases the fertility of daughters and increases cancer and asthma incidence in grandchildren and great-grandchildren. STUDY DESIGN, SIZE, DURATION Six-week-old C57BL/6 female mice were exposed nasally to cigarette smoke or room air (controls) for 5 weeks prior to being housed with males. Females continued to be exposed to smoke throughout pregnancy and lactation until pups were weaned. A subset of F1 female pups born to these smoke and non-smoke exposed females were bred to create the F2 grandmaternal exposed generation (multigenerational). Finally, a subset of F2 females were bred to create the F3 great-grandmaternal exposed generation (transgenerational). The reproductive health of F2 and F3 females was examined at 8 weeks and 9 months. PARTICIPANTS/MATERIALS, SETTING, METHODS Ovarian and oocyte quality was examined in smoke exposed and control animals. A small-scale fertility trial was performed before ovarian changes were examined using ovarian histology and immunofluorescence and/or immunoblotting analysis of markers of apoptosis (TUNEL) and proliferation (proliferating cell nuclear antigen (PCNA) and anti-Mullerian hormone (AMH)). Oocyte quality was examined using immunocytochemistry to analyze the metaphase II spindle and ploidy status. Parthenogenetic activation of oocytes was used to investigate meiosis II timing and preimplantation embryo development. Finally, diestrus hormone serum levels (FSH and LH) were quantified. MAIN RESULTS AND THE ROLE OF CHANCE F2 smoke exposed females had no detectable change in ovarian follicle quality at 8 weeks, although by 9 months ovarian somatic cell proliferation was reduced (P = 0.0197) compared with non-smoke exposed control. Further investigation revealed changes between control and smoke exposed F2 oocyte quality, including altered meiosis II timing at 8 weeks (P = 0.0337) and decreased spindle pole to pole length at 9 months (P = 0.0109). However, no change in preimplantation embryo development was observed following parthenogenetic activation. The most noticeable effect of cigarette smoke exposure was related to the subfertility of F2 females; F2 smoke exposed females displayed significantly increased time to conception (P = 0.0042) and significantly increased lag time between pregnancies (P = 0.0274) compared with non-smoke exposed F2 females. Conversely, F3 smoke exposed females displayed negligible oocyte and follicle changes up to 9 months of age, and normal preimplantation embryo development. LARGE SCALE DATA None. LIMITATIONS, REASONS FOR CAUTION This study focused solely on a mouse model of cigarette smoke exposure to simulate human exposure. WIDER IMPLICATIONS OF THE FINDINGS Our results demonstrate that grandmaternal cigarette smoke exposure reduces female fertility in mice, highlighting the clinical need to promote cessation of cigarette smoking in pregnant women. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by the Australian Research Council, National Health and Medical Research Council, Hunter Medical Research Institute, Newcastle Permanent Building Society Charitable Trust, and the University of Newcastle Priory Research Centers in Chemical Biology, Healthy Lungs and Grow Up Well. The authors declare no conflict of interest.
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Walters KA, Edwards MC, Tesic D, Caldwell ASL, Jimenez M, Smith JT, Handelsman DJ. The Role of Central Androgen Receptor Actions in Regulating the Hypothalamic-Pituitary-Ovarian Axis. Neuroendocrinology 2018; 106:389-400. [PMID: 29635226 DOI: 10.1159/000487762] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/16/2018] [Indexed: 12/20/2022]
Abstract
The androgen receptor (AR) is expressed throughout the hypothalamic-pituitary-gonadal (HPG) axis, and findings from female global AR knockout mice confirm that AR-mediated androgen actions play important roles in regulating female reproductive function. We generated neuron-specific AR knockout mice (NeurARKO) to investigate the functional role of neuronal AR-mediated androgen action in regulating the female HPG axis and fertility. Relative to control females, NeurARKO females exhibited elevated luteinizing hormone (LH) levels at diestrus (p < 0.05) and a compromised serum LH response to ovariectomy and E2 priming (p < 0.01). Furthermore, NeurARKO females displayed reduced Kiss1 mRNA expression in the anteroventral periventricular nucleus at diestrus (p < 0.05) and proestrus (p < 0.05), but elevated Kiss1 (p < 0.05) and neurokinin B (Tac2, p < 0.05) mRNA expression in the arcuate nucleus at proestrus compared to WT controls. Ovarian follicle dynamics were also altered in NeurARKO ovaries at 3 months of age, with a significant reduction in large antral follicle numbers at the proestrus stage compared to control WT ovaries (p < 0.05). Increased follicular atresia was evident in NeurARKO ovaries with a 4-fold increase in unhealthy large preantral follicles (p < 0.01). Despite the findings of aberrant neuroendocrine and ovarian characteristics in the NeurARKO females, estrous cyclicity and overall fertility were comparable between NeurARKO and WT females. In conclusion, our findings revealed that selective loss of neuronal AR actions impacts the kisspeptin/GnRH/LH cascade leading to compromised ovarian follicle dynamics.
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Rodgers RJ, Reid GD, Koch J, Deans R, Ledger WL, Friedlander M, Gilchrist RB, Walters KA, Abbott JA. The safety and efficacy of controlled ovarian hyperstimulation for fertility preservation in women with early breast cancer: a systematic review. Hum Reprod 2017; 32:1033-1045. [DOI: 10.1093/humrep/dex027] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/29/2017] [Indexed: 12/29/2022] Open
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Walters KA, Handelsman DJ. Androgen receptor splice variants and polycystic ovary syndrome: cause or effect? Asian J Androl 2017; 18:442-3. [PMID: 26306851 PMCID: PMC4854100 DOI: 10.4103/1008-682x.161600] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Solon-Biet SM, Cogger VC, Pulpitel T, Heblinski M, Wahl D, McMahon AC, Warren A, Durrant-Whyte J, Walters KA, Krycer JR, Ponton F, Gokarn R, Wali JA, Ruohonen K, Conigrave AD, James DE, Raubenheimer D, Morrison CD, Le Couteur DG, Simpson SJ. Defining the Nutritional and Metabolic Context of FGF21 Using the Geometric Framework. Cell Metab 2016; 24:555-565. [PMID: 27693377 DOI: 10.1016/j.cmet.2016.09.001] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 06/30/2016] [Accepted: 08/31/2016] [Indexed: 12/11/2022]
Abstract
Fibroblast growth factor 21 (FGF21) is the first known endocrine signal activated by protein restriction. Although FGF21 is robustly elevated in low-protein environments, increased FGF21 is also seen in various other contexts such as fasting, overfeeding, ketogenic diets, and high-carbohydrate diets, leaving its nutritional context and physiological role unresolved and controversial. Here, we use the Geometric Framework, a nutritional modeling platform, to help reconcile these apparently conflicting findings in mice confined to one of 25 diets that varied in protein, carbohydrate, and fat content. We show that FGF21 was elevated under low protein intakes and maximally when low protein was coupled with high carbohydrate intakes. Our results explain how elevation of FGF21 occurs both under starvation and hyperphagia, and show that the metabolic outcomes associated with elevated FGF21 depend on the nutritional context, differing according to whether the animal is in a state of under- or overfeeding.
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Shankara-Narayana N, Zawada S, Walters KA, Desai R, Marren A, Handelsman DJ. Accuracy of a Direct Progesterone Immunoassay. ACTA ACUST UNITED AC 2016; 1:294-299. [DOI: 10.1373/jalm.2016.020123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 11/06/2022]
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Upton DH, Walters KA, Allavena RE, Jimenez M, Desai R, Handelsman DJ, Allan CM. Global or Granulosa Cell-Specific Pten Mutations in Combination with Elevated FSH Levels Fail to Cause Ovarian Tumours in Mice. Discov Oncol 2016; 7:316-326. [PMID: 27506975 DOI: 10.1007/s12672-016-0272-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/25/2016] [Indexed: 01/22/2023] Open
Abstract
Phosphatase and tensin homologue (PTEN) is a known tumour suppressor. To explore the role of Pten in ovarian tumorigenesis, we used transgenic (Tg) SOX2. Cre and AMH. Cre mouse models to direct global Pten haploinsufficiency (Pten +/-) or ovary-specific granulosa cell (GC) Pten disruption (Pten GC ). Pten mutant models were combined with progressively rising Tg-follicle-stimulating hormone (TgFSH) levels to study the tumorigenic potential of combined genetic/endocrine modification in vivo. Global Pten +/- mice exhibited grossly detectable tumours in multiple organs including uterine and mammary tissue and displayed reduced survival. Despite extra-ovarian tumorigenesis, Pten +/- females had no detectable ovarian tumours, although elevated corpus luteum numbers increased ovary size and estrous cycling was altered. Combined TgFSH/Pten +/- mice also had no ovarian tumours, but early survival was reduced in the presence of TgFSH. Ovary-specific Pten GC ± TgFSH females exhibited no detectable ovarian or uterine tumours, and corpus luteum numbers and estrous cycling remained unchanged. The non-tumorigenic ovarian phenotypes in Pten +/- and Pten GC ± TgFSH mice support the proposal that multi-hit genetic mutations (including ovarian and extra-ovarian tissue) initiate ovarian tumours. Our findings suggest that elevated FSH may reduce early cancer survival; however, the ovary remains remarkably resistant to Pten-induced tumorigenic changes even in the presence of uterine and reproductive cancers.
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Abstract
PURPOSE OF REVIEW In the last decade, it has been proven that androgens acting via the androgen receptor (AR) play an important role in the regulation of female reproductive function. However, the specific site of action and the precise pathways involved remain to be fully elucidated. This review aims to combine findings from emerging basic research to provide new insights into the roles of AR-mediated actions, and the mechanisms involved, in normal ovarian, uterine, and mammary gland function. RECENT FINDINGS Our understanding of the specific roles of androgens in females has been hindered as females with complete androgen insensitivity cannot be generated by natural breeding, and interpretation of results from pharmacological studies has led to confusion as some androgens can be converted into estrogens, which can mediate actions via estrogen receptors. However, with the creation of global and cell-specific female AR knockout mouse models by Cre-LoxP technology, and the use of aromatizable and nonaromatizable androgens, novel roles for androgens in the regulation of female reproductive physiology have been revealed. SUMMARY AR-mediated mechanisms play important roles in mediating normal ovarian, uterine, and mammary gland function and there is hope that further elucidation of the role of androgens in female reproductive physiology may translate into the development of novel, evidence-based, and targeted treatment for androgen-associated conditions.
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Abstract
PURPOSE OF REVIEW There is substantial evidence to support a role for androgens acting via the androgen receptor in the development of the pathological disorder, polycystic ovary syndrome (PCOS). PCOS is the most common endocrine condition in women, but its etiology remains unknown. This review focuses on how animal experimental models of PCOS are providing strong evidence to support hyperandrogenism as an important mediator in the development of PCOS characteristics. RECENT FINDINGS A variety of animal models for PCOS have now been established by increasing androgen exposure, supporting a role for androgens in the pathogenesis of PCOS. However, some androgens can be aromatized into estrogens leading to confusion on which PCOS traits are primary mediated via androgenic (mediated via the androgen receptor) or estrogenic (mediated via the estrogen receptor) mechanisms. Recent findings from studies comparing the induction of PCOS by aromatizable and nonaromatizable androgens, as well as androgen receptor knockout mouse models have enhanced our understanding of the mechanisms underlying PCOS, and verify that androgen receptor-mediated actions play a key role in the development of PCOS. SUMMARY Animal models have provided strong evidence to support that androgen receptor-mediated actions are key mediators in the development of PCOS traits.
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Wang X, Gook DA, Walters KA, Anazodo A, Ledger WL, Gilchrist RB. Improving fertility preservation for girls and women by coupling oocyte in vitro maturation with existing strategies. ACTA ACUST UNITED AC 2016; 12:275-8. [PMID: 27188229 DOI: 10.2217/whe-2016-0019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Androgens mediate their actions via the androgen receptor (AR), a member of the nuclear receptor superfamily. AR-mediated androgen action is essential in male reproductive development and function; however, only in the last decade has the suspected but unproven role for AR-mediated actions in female reproduction been firmly established. Deciphering the specific roles and precise pathways by which AR-mediated actions regulate ovarian function has been hindered by confusion on how to interpret results from pharmacological studies using androgens that can be converted into oestrogens, which exert actions via the oestrogen receptors. The generation and analysis of global and cell-specific femaleArknockout mouse models have deduced a role for AR-mediated actions in regulating ovarian function, maintaining female fertility, and have begun to unravel the mechanisms by which AR-mediated androgen actions regulate follicle health, development and ovulation. Furthermore, observational findings from human studies and animal models provide substantial evidence to support a role for AR-mediated effects not only in normal ovarian function but also in the development of the frequent ovarian pathological disorder, polycystic ovarian syndrome (PCOS). This review focuses on combining the findings from observational studies in humans, pharmacological studies and animal models to reveal the roles of AR-mediated actions in normal and pathological ovarian function. Together these findings will enable us to begin understanding the important roles of AR actions in the regulation of female fertility and ovarian ageing, as well as providing insights into the role of AR actions in the androgen-associated reproductive disorder PCOS.
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Caldwell ASL, Eid S, Kay CR, Jimenez M, McMahon AC, Desai R, Allan CM, Smith JT, Handelsman DJ, Walters KA. Haplosufficient genomic androgen receptor signaling is adequate to protect female mice from induction of polycystic ovary syndrome features by prenatal hyperandrogenization. Endocrinology 2015; 156:1441-52. [PMID: 25643156 DOI: 10.1210/en.2014-1887] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Polycystic ovary syndrome (PCOS) is associated with reproductive, endocrine, and metabolic abnormalities. Because hyperandrogenism is the most consistent PCOS feature, we used wild-type (WT) and androgen receptor (AR) knockout (ARKO) mice, together with a mouse model of PCOS, to investigate the contribution of genomic AR-mediated actions in the development of PCOS traits. PCOS features were induced by prenatal exposure to dihydrotestosterone (250 μg) or oil vehicle (control) on days 16-18 of gestation in WT, heterozygote, and homozygote ARKO mice. DHT treatment of WT mice induced ovarian cysts (100% vs 0%), disrupted estrous cycles (42% vs 100% cycling), and led to fewer corpora lutea (5.0±0.4 vs 9.8±1.8). However, diestrus serum LH and FSH, and estradiol-induced-negative feedback as well as hypothalamic expression of kisspeptin, neurokinin B, and dynorphin, were unaffected by DHT treatment in WT mice. DHT-treated WT mice exhibited a more than 48% increase in adipocyte area but without changes in body fat. In contrast, heterozygous and homozygous ARKO mice exposed to DHT maintained comparable ovarian (histo)morphology, estrous cycling, and corpora lutea numbers, without any increase in adipocyte size. These findings provide strong evidence that genomic AR signaling is an important mediator in the development of these PCOS traits with a dose dependency that allows even AR haplosufficiency to prevent induction by prenatal androgenization of PCOS features in adult life.
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Handelsman DJ, Jimenez M, Singh GKS, Spaliviero J, Desai R, Walters KA. Measurement of testosterone by immunoassays and mass spectrometry in mouse serum, testicular, and ovarian extracts. Endocrinology 2015; 156:400-5. [PMID: 25365769 DOI: 10.1210/en.2014-1664] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Accurate measurement of testosterone is important for reproductive endocrinology research, but the validity of direct (nonextraction) testosterone immunoassays, developed and validated for human serum, has not been appraised for application to mouse serum or steroidogenic tissue extracts. Testosterone was measured in serum and extracts of testis or ovary from male and female wild-type mice by 2 commercial direct testosterone immunoassays, with and without preassay extraction, and by the liquid chromatography, tandem mass spectrometry reference method. Results were compared hierarchically by correlation (Kendall's τ), regression (Passing-Bablok), and deviance (Bland-Altman) analysis, under the null hypothesis of perfect agreement between assays (slope = 1, intercept and deviation = 0). For mouse serum, immunoassays displayed an upward bias with performance better for male vs female sera and, within gender, improved by preassay extraction relative to liquid chromatography, tandem mass spectrometry. Testosterone was detectable in all serum samples, but few (male 54%, female 9%) were accurate (within 20% of the reference measurement). For mouse testis extracts, immunoassays were biased upwards, and preassay extraction improved immunoassay performance. Although testosterone was detectable in all extracts, a minority (45%) was accurate. For mouse ovary extracts, all correlations were poor with severe, upward bias, and while testosterone was detectable in all samples, virtually none were accurate. We conclude that these direct testosterone immunoassay kits provide relatively, but not absolutely, accurate results with male mouse serum and testis extracts but not with female mouse serum and ovary extracts, with performance improved by preassay extraction. Whether relative accuracy is fit for purpose depends on the experimental aims, design, and interpretation.
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Gao YRE, Walters KA, Desai R, Zhou H, Handelsman DJ, Simanainen U. Androgen receptor inactivation resulted in acceleration in pubertal mammary gland growth, upregulation of ERα expression, and Wnt/β-catenin signaling in female mice. Endocrinology 2014; 155:4951-63. [PMID: 25076121 DOI: 10.1210/en.2014-1226] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The androgen receptor (AR) is widely expressed in mammary cells of female mammals including humans and mice, indicating a possible role for AR-mediated androgen actions in breast development, function, and pathology, although the specific mechanisms remain unclear. To elucidate the mechanisms of androgen action in mammary gland physiology and development, we used AR-knockout (AR(Δex3)KO) female mice with a universally expressed, transcriptionally inactive AR protein harboring an in-frame deletion of its second zinc finger. Although in sexually mature wild-type (WT) and AR(ex3Δ)KO females, the mammary epithelial growth was fully extended to the edge of the fat pad, during puberty, AR(ex3Δ)KO females exhibit significantly accelerated mammary ductal growth and an increased number of terminal end buds compared with WT females. Accelerated AR(ex3Δ)KO female mammary growth was associated with significantly increased mammary epithelial ERα expression and activated Wnt/β-catenin signaling as shown by increased Wnt4 expression and accumulation of nuclear β-catenin. These findings are consistent with increased mammary estrogen exposure although ovarian estradiol content was unchanged compared with WT females. Furthermore, treatment with the potent pure androgen DHT markedly reduced ductal extension and terminal end bud numbers in WT but not in AR(Δex3)KO females, further supporting the concept that AR-mediated, androgen-induced suppression of murine mammary growth is a physiological characteristic of puberty. In summary, our findings reveal an inhibitory role of AR-mediated androgen actions in pubertal mammary gland development by reducing epithelial cell proliferation and could be mediated by regulation of Wnt/β-catenin signaling.
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Caldwell ASL, Middleton LJ, Jimenez M, Desai R, McMahon AC, Allan CM, Handelsman DJ, Walters KA. Characterization of reproductive, metabolic, and endocrine features of polycystic ovary syndrome in female hyperandrogenic mouse models. Endocrinology 2014; 155:3146-59. [PMID: 24877633 DOI: 10.1210/en.2014-1196] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Polycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age, causing a range of reproductive, metabolic and endocrine defects including anovulation, infertility, hyperandrogenism, obesity, hyperinsulinism, and an increased risk of type 2 diabetes and cardiovascular disease. Hyperandrogenism is the most consistent feature of PCOS, but its etiology remains unknown, and ethical and logistic constraints limit definitive experimentation in humans to determine mechanisms involved. In this study, we provide the first comprehensive characterization of reproductive, endocrine, and metabolic PCOS traits in 4 distinct murine models of hyperandrogenism, comprising prenatal dihydrotestosterone (DHT, potent nonaromatizable androgen) treatment during days 16-18 of gestation, or long-term treatment (90 days from 21 days of age) with DHT, dehydroepiandrosterone (DHEA), or letrozole (aromatase inhibitor). Prenatal DHT-treated mature mice exhibited irregular estrous cycles, oligo-ovulation, reduced preantral follicle health, hepatic steatosis, and adipocyte hypertrophy, but lacked overall changes in body-fat composition. Long-term DHT treatment induced polycystic ovaries displaying unhealthy antral follicles (degenerate oocyte and/or > 10% pyknotic granulosa cells), as well as anovulation and acyclicity in mature (16-week-old) females. Long-term DHT also increased body and fat pad weights and induced adipocyte hypertrophy and hypercholesterolemia. Long-term letrozole-treated mice exhibited absent or irregular cycles, oligo-ovulation, polycystic ovaries containing hemorrhagic cysts atypical of PCOS, and displayed no metabolic features of PCOS. Long-term dehydroepiandrosterone treatment produced no PCOS features in mature mice. Our findings reveal that long-term DHT treatment replicated a breadth of ovarian, endocrine, and metabolic features of human PCOS and provides the best mouse model for experimental studies of PCOS pathogenesis.
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Cheng XB, Jimenez M, Desai R, Middleton LJ, Joseph SR, Ning G, Allan CM, Smith JT, Handelsman DJ, Walters KA. Characterizing the neuroendocrine and ovarian defects of androgen receptor-knockout female mice. Am J Physiol Endocrinol Metab 2013; 305:E717-26. [PMID: 23880317 DOI: 10.1152/ajpendo.00263.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Homozygous androgen receptor (AR)-knockout (ARKO) female mice are subfertile due to both intra- and extraovarian (neuroendocrine) defects as defined by ovary transplantation. Using ARKO mice, this study set out to reveal the precise AR-regulated pathways required for optimal androgen-regulated ovulation and fertility. ARKO females exhibit deficient neuroendocrine negative feedback, with a reduced serum luteinizing hormone (LH) response to ovariectomy (OVX) (P < 0.01). Positive feedback is also altered as intact ARKO females, at late proestrus, exhibit an often mistimed endogenous ovulatory LH surge. Furthermore, at late proestrus, intact ARKO females display diminished preovulatory serum estradiol (E2; P < 0.01) and LH (P < 0.05) surge levels and reduced Kiss1 mRNA expression in the anteroventral periventricular nucleus (P < 0.01) compared with controls. However, this reduced ovulatory LH response in intact ARKO females can be rescued by OVX and E2 priming or treatment with endogenous GnRH. These findings reveal that AR regulates the negative feedback response to E2, E2-positive feedback is compromised in ARKO mice, and AR-regulated negative and positive steroidal feedback pathways impact on intrahypothalamic control of the kisspeptin/GnRH/LH cascade. In addition, intraovarian AR-regulated pathways controlling antral to preovulatory follicle dynamics are disrupted because adult ARKO ovaries collected at proestrus have small antral follicles with reduced oocyte/follicle diameter ratios (P < 0.01) and increased proportions of unhealthy large antral follicles (P < 0.05) compared with controls. As a consequence of aberrant follicular growth patterns, proestrus ARKO ovaries also exhibit fewer preovulatory follicle (P < 0.05) and corpora lutea numbers (P < 0.01). However, embryo development to the blastocyst stage is unchanged in ARKO females, and hence, the subfertility is a consequence of reduced ovulations and not altered embryo quality. These findings reveal that the AR has a functional role in neuroendocrine regulation and timing of the ovulatory LH surge as well as antral/preovulatory follicle development.
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