| Yes1 associated transcriptional regulator | OKDB#: 3424 |
| Symbols: | YAP1 | Species: | human | ||
| Synonyms: | YAP, YKI, COB1, YAP2, YAP65 | Locus: | 11q22.1 in Homo sapiens |
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| General Comment |
Surgical approaches of drug-free in vitro activation and laparoscopic ovarian incision to treat patients with ovarian infertility. Tanaka Y et al. (2020) To demonstrate our procedures of drug-free in vitro activation (IVA) for treating patients with premature ovarian insufficiency (POI) or diminished ovarian reserve (DOR), as well as the laparoscopic ovarian incision (LOI) procedure for treating patients with resistant ovary syndrome (ROS). Step-by-step video demonstration of the surgical procedures. Fertility clinic and reproductive medicine department. Women were diagnosed with POI based on recent amenorrhea before 40 years of age or with DOR according to the Bologna criteria, showing growth of a few antral follicles after ovarian stimulation. ROS patients were diagnosed based on amenorrhea with hypergonadotropic hypoestrogenism but showing age-appropriate number of antral follicles under transvaginal ultrasound. The drug-free IVA consists of the following 4 steps: removing a part of the cortex from one or both ovaries; cutting ovarian cortical pieces into small cubes in vitro; making pockets for ovarian tissue grafting; and grafting ovarian cortical cubes. The LOI procedure consisted of only one step: cutting ovarian cortex in situ. Both procedures were followed by ovarian hyperstimulation for at least 1 year. Informed consent was obtained from patients and approval was granted by the Biomedical Ethics Committee of the International University School of Medicine and the Rose Ladies Clinic. The present clinical trial was carried out in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki). Follicle growth. These procedures can be completed within 1 hour under laparoscopic surgery. There were no complications. In 13 of 15 patients treated with drug-free IVA, increases in antral follicle numbers were found, followed by a higher number of retrieved oocytes for in vitro fertilization. In addition to one spontaneous pregnancy, embryo transfer allowed four live births and one ongoing pregnancy. Five additional patients and one miscarriage patient have cryopreserved embryos for future transfer. We also found follicle growth to the preovulatory stage in seven of 11 ROS patients who have not responded to any endogenous and exogenous follicle-stimulating hormone stimulations for follicle growth prior to LOI treatment, allowing the retrieval of mature oocytes for in vitro fertilization. Four ROS patients became pregnant, followed by the delivery of three healthy infants and one ongoing pregnancy. A drug-free IVA approach provided an infertility treatment for recent POI or DOR patients. This procedure promoted growth of residual ovarian follicles following ovarian tissue fragmentation in vitro, leading to Hippo signaling disruption. Although ROS patients exhibited symptoms of hypergonadotropic hypoestrogenism similar to that of POI patients, they still had multiple secondary follicles. Hippo signaling disruption in vivo based on cutting ovarian cortex using LOI could promote follicle growth. UMIN000029807.////////////////// Drug-free in-vitro activation of follicles for infertility treatment in poor ovarian response patients with decreased ovarian reserve. Kawamura K et al. (2019) The recently developed in-vitro activation (IVA) approach provides a promising infertility treatment for patients with premature ovarian insufficiency. The IVA method promotes growth of residual ovarian follicles following ovarian tissue fragmentation leading to Hippo signalling disruption, together with in-vitro incubation with Akt stimulators. As poor ovarian response (POR) patients with decreased ovarian reserve (DOR) have multiple secondary follicles, this study tested whether Hippo signalling disruption alone using in-vitro ovarian cortical fragmentation, followed by autologous grafting, was sufficient to promote follicle growth. A case series study. In 9 out of 11 POR patients with DOR treated with a simplified IVA procedure, increases in antral follicle numbers in multiple growth waves were detected following FSH treatment. Subsequent injection with human chorionic gonadotrophin allowed retrieval of more mature oocytes for IVF (median antral follicle counts before and after IVA per ovarian stimulation: 1.0 versus 2.6) with 68.7% fertilization rates and 56.9% showing high-quality embryonic development. One natural conception and 16 embryo transfers in five patients resulted in one live birth, two ongoing pregnancies and one miscarriage. Three additional patients and the miscarriage patient have cryopreserved embryos for future transfer. The present drug-free IVA approach may be suitable for POR patients with DOR, as it increased the number of antral follicles. The procedure also eliminated the need for 2-day incubation with drugs and required only one surgery. This approach could allow the retrieval of more oocytes in middle-aged women to achieve higher pregnancy rates and deserves proper evaluation in future randomized controlled trials.//////////////////In vitro activation of ovarian cortex and autologous transplantation: A novel approach to primary ovarian insufficiency and diminished ovarian reserve. Devenutto L et al. (2020) Primary ovarian insufficiency (POI) and diminished ovarian reserve are two conditions that affect women's fertility. Oocyte donation remains an option for these patients; however, the development of certain novel technologies, such as in vitro activation of ovarian cortex (IVA), enables the possibility of activating the pool of resting primordial follicles, increasing the chance of pregnancy. Here, we review the main pathways (PI3K and Hippo signaling) that govern the activation of primordial follicles and its application through the development of culture systems that support ovarian cortex for autologous transplantation. We also review the available data from case reports regarding outcomes of pregnancy and live birth rates with IVA. A PubMed search was conducted using the PubMed-NCBI database to identify literature pertinent to the pathways involved in the activation of primordial follicles and the outcomes of IVA techniques from 2013 to the present. Women with POI have around a 5% chance of spontaneous pregnancy. Recently, novel techniques involving the activation of primordial follicles through molecular pathways have been developed, thus increasing the odds of these patients. More recently, the introduction of a drug-free IVA technique has shown to increase the number of antral follicles with successful oocyte maturation after gonadotropin treatment, reaching pregnancy rates over 30%, either through spontaneous conception or by the implementation of assisted reproductive technology. The evidence of this review is based on a few small series, so data should be interpreted with caution, and only randomized controlled trials could estimate the real magnitude and success of the procedure. IVA technique remains an experimental strategy, with limited available data and the requirement of invasive procedures. Moreover, possible carcinogenic effects not yet determined after transplantation require special caution. In view of the results achieved, IVA could provide a promising option for the preservation of fertility in some cancer patients and prepuberal girls where the only alternative is tissue cryopreservation. The authors received no specific funding for this work and declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.//////////////////
Intraovarian control of early folliculogenesis. Hsueh AJ 2014 et al.
Although hormonal regulation of ovarian follicle development has been extensively investigated, most studies concentrate on the development of early antral follicles to the preovulatory stage, leading to the successful use of exogenous FSH for infertility treatment. Accumulating data indicate that preantral follicles are under stringent regulation by FSH and local intra-ovarian factors, thus providing the possibility to develop new therapeutic approaches. Granulosa cell-derived C-type natriuretic factor (CNP) not only suppresses the final maturation of oocytes to undergo germinal vesicle breakdown before ovulation but also promotes preantral and antral follicle growth. In addition, several oocyte-and granulosa cell-derived factors stimulate preantral follicle growth by acting through WNT, receptor tyrosine kinase, receptor serine kinase, and other signaling pathways. In contrast, the ovarian Hippo signaling pathway constrains follicle growth and disruption of Hippo signaling promotes the secretion of downstream CCN growth factors capable of promoting follicle growth. Although the exact hormonal factors involved in primordial follicle activation has yet to be elucidated, the AKT and mTOR signaling pathways are important for the activation of dormant primordial follicles. Hippo signaling disruption following ovarian fragmentation, combined with treating ovarian fragments with PTEN inhibitors and phosphoinositide-3-kinase stimulators to augment AKT signaling, promote the growth of preantral follicles in patients with primary ovarian insufficiency (POI), leading to a new infertility intervention for such patients. Elucidation of intraovarian mechanisms underlying early folliculogenesis may allow the development of novel therapeutic strategies for patients diagnosed with POI, polycystic ovary syndrome (PCOS), and poor ovarian response to FSH stimulation, as well as for infertile women of advanced reproductive age.
//////////////////////// . Drug-free in-vitro activation of follicles and fresh tissue autotransplantation as a therapeutic option in patients with primary ovarian insufficiency. Ferreri J et al. (2020) Could in-vitro action of follicles and fresh tissue autotransplantation without tissue culture (drug-free IVA) be useful in patients with primary ovarian insufficiency (POI)? Prospective observational cohort study in a tertiary university hospital. Drug-Free IVA was carried out in 14 women with POI with a median age of 33 years (29-36 years), median length of amenorrhoea of 1.5 years (1-11 years), median FSH levels 69.2 mIU/ml (36.9-82.8 mIU/ml) and anti-Müllerian hormone of 0.02 ng/ml (0.01-0.1 ng/ml). The surgical procedure included laparoscopic removal of ovarian cortex, fragmentation of tissue and autografting. Human menopausal gonadotrophin (HMG) was started immediately after surgery. Follicle development was detected in seven out of the 14 patients, and five women achieved successful oocyte retrieval. In six women, HCG was administered in 10 cycles. Six embryo transfers were carried out in five women resulting in four pregnancies; a clinical pregnancy rate of four in seven oocyte retrievals and four in six embryo transfers. Drug-free IVA could be a useful therapeutic option for patients with POI, leading to successful IVF outcomes.////////////////// The hippo pathway regulates homeostatic growth of stem cell niche precursors in the Drosophila ovary. Sarikaya DP et al. (2015) The Hippo pathway regulates organ size, stem cell proliferation and tumorigenesis in adult organs. Whether the Hippo pathway influences establishment of stem cell niche size to accommodate changes in organ size, however, has received little attention. Here, we ask whether Hippo signaling influences the number of stem cell niches that are established during development of the Drosophila larval ovary, and whether it interacts with the same or different effector signaling pathways in different cell types. We demonstrate that canonical Hippo signaling regulates autonomous proliferation of the soma, while a novel hippo-independent activity of Yorkie regulates autonomous proliferation of the germ line. Moreover, we demonstrate that Hippo signaling mediates non-autonomous proliferation signals between germ cells and somatic cells, and contributes to maintaining the correct proportion of these niche precursors. Finally, we show that the Hippo pathway interacts with different growth pathways in distinct somatic cell types, and interacts with EGFR and JAK/STAT pathways to regulate non-autonomous proliferation of germ cells. We thus provide evidence for novel roles of the Hippo pathway in establishing the precise balance of soma and germ line, the appropriate number of stem cell niches, and ultimately regulating adult female reproductive capacity./////////////////Cutting the ovarian surface improves the responsiveness to exogenous hormonal treatment in aged mice 2020
NCBI Summary: This gene encodes a downstream nuclear effector of the Hippo signaling pathway which is involved in development, growth, repair, and homeostasis. This gene is known to play a role in the development and progression of multiple cancers as a transcriptional regulator of this signaling pathway and may function as a potential target for cancer treatment. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Aug 2013] |
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| General function | Transcription factor | ||||
| Comment | Enhancing the safety of ovarian cortex autotransplantation: cancer cells are purged completely from human ovarian tissue fragments by pharmacological inhibition of YAP/TAZ oncoproteins. Mulder CL et al. (2018) Is it possible to eliminate metastasized cancer cells from ovarian cortex fragments prior to autotransplantation without compromising the ovarian tissue or follicles? Ex vivo pharmacological inhibition of YAP/TAZ by Verteporfin enabled us to efficiently eradicate experimentally induced small tumours, derived from leukaemia and rhabdomyosarcoma, from human ovarian tissue fragments. Autotransplantation of ovarian tissue fragments that contain metastasized tumour cells may reintroduce the malignancy to the recipient. In order to enhance safety for the patient there is a strong need for protocols that effectively purges the ovarian tissue from malignant cells ex vivo prior to transplantation, without compromising ovarian tissue integrity. Tumour foci were experimentally induced in human ovarian cortex tissue fragments derived from at least three patients by micro-injection of cancer cell lines. Next, the tissue fragments were cultured to allow formation of metastasis-like structures followed by a 24 h ex vivo treatment with the YAP/TAZ inhibitor Verteporfin to eradicate the cancer cells. A control treatment was included in all experiments. The purged ovarian cortex fragments were cultured for an additional 6 days to allow any possibly surviving cancer cells to establish new metastatic foci. Human ovarian tissue was obtained after female-to-male sex reassignment surgery. Human rhabdomyosarcoma, leukeamia, breast cancer and Ewing's sarcoma cell lines were utilized for the induction of tumour foci. Tumour specific (immuno)histochemistry and RT-PCR were used for the detection of residual cancer cells after ex vivo treatment. Ovarian tissue and follicle integrity after exposure to Verteporfin was evaluated by histology, a follicular viability assay and a glucose uptake assay. Metastasized rhabdomyosarcoma and leukaemia cells could be effectively purged from ovarian cortex tissue by a 24 h ex vivo treatment with Verteporfin, while breast cancer and Ewing's sarcoma did not respond to this treatment. Ovarian tissue integrity was not affected by purging, as no statistically significant difference (P > 0.05) was observed in the percentage of morphologically normal follicles, percentage of follicles with apoptotic cells, follicular viability or glucose uptake between the control treated ovarian cortex and Verteporfin treated ovarian cortex. Our tumour model is based on growth of human cancer cell lines. It is unclear whether these cells reflect the behaviour of malignant cells that have metastasized to the ovary during natural disease progression. Furthermore, the functionality of the ovarian tissue after ex vivo treatment requires further investigation in vivo. The results indicate that ex-vivo tumour cell purging of human ovarian cortex fragments intended for fertility preservation purposes is feasible by short-term pharmacological treatment. Effective purging of the ovarian cortex tissue enhances safety of ovarian cortex autotransplantation for the patient. This increases the likelihood that this form of fertility restoration may become an option for patients with malignancies for which ovarian cortex transplantation is currently considered unsafe. Unconditional funding was received from Merck B.V. The Netherlands (Number 2016-FERT-1) and the foundation 'Radboud Oncologie Fonds' (Number KUN 00007682). The authors have no conflicts of interest. NA.////////////////// . Targeting Hippo pathway by specific interruption of YAP-TEAD interaction using cyclic YAP-like peptides. Zhou Z et al. (2014) Hippo signaling pathway is emerging as a novel target for anticancer therapy because it plays key roles in organ size control and tumorigenesis. As the downstream effectors, Yes-associated protein (YAP)-transcriptional enhancer activation domain family member (TEAD) association is essential for YAP-driven oncogenic activity, while TEAD is largely dispensable for normal tissue growth. We present the design of YAP-like peptides (17mer) to occupy the interface 3 on TEAD. Introducing cysteines at YAP sites 87 and 96 can induce disulfide formation, as confirmed by crystallography. The engineered peptide significantly improves the potency in disrupting YAP-TEAD interaction in vitro. To confirm that blocking YAP-TEAD complex formation by directly targeting on TEAD is a valid approach, we report a significant reduction in tumor growth rate in a hepatocellular carcinoma xenograft model after introducing the dominant-negative mutation (Y406H) of TEAD1 to abolish YAP-TEAD interaction. Our results suggest that targeting TEAD is a promising strategy against YAP-induced oncogenesis.-Zhou, Z., Hu, T., Xu, Z., Lin, Z., Zhang, Z., Feng, T., Zhu, L., Rong, Y., Shen, H., Luk, J.M., Zhang, X., Qin, N. Targeting Hippo pathway by specific interruption of YAP-TEAD interaction using cyclic YAP-like peptides.////////////////// Needs to bind TEAD transcriptional factors to regulate transcription.////////The clinically used photosensitizer Verteporfin (VP) inhibits YAP-TEAD and human retinoblastoma cell growth in vitro without light activation. Brodowska K 2014 et al. Verteporfin (VP), a benzoporphyrin derivative, is clinically used in photodynamic therapy for neovascular macular degeneration. Recent studies indicate that VP may inhibit growth of hepatoma cells without photoactivation hrough inhibition of YAP-TEAD complex. In this study, we examined the effects of VP without light activation on human retinoblastoma cell lines. Verteporfin but not vehicle control inhibited the growth, proliferation and viability of human retinoblastoma cell lines (Y79 and WERI) in a dose-dependent manner and was associated with downregulation of YAP-TEAD associated downstream proto-oncogenes such as c-myc, axl, and surviving. In addition VP affected signals involved in cell migration and angiogenesis such as CTGF, cyr61, and VEGF-A but was not associated with significant effect on the mTOR/autophagy pathway. Of interest the pluripotency marker Oct4 were downregulated by Verteporfin treatment. Our results indicate that the clinically used photosensitizer VP is a potent inhibitor of cell growth in retinoblastoma cells, disrupting YAP-TEAD signaling and pluripotential marker OCT4. This study highlights for the first time the role of the YAP-TEAD pathway in Retinoblastoma and suggests that VP may be a useful adjuvant therapeutic tool in treating Rb patients. ///////////////////////// | ||||
| Cellular localization | Cytoplasmic, Nuclear | ||||
| Comment | GWAS123 | ||||
| Ovarian function | Initiation of primordial follicle growth, Primary follicle growth, Preantral follicle growth, Antral follicle growth, Ovulation, Luteinization, Early embryo development | ||||
| Comment | Hippo signaling disruption and Akt stimulation of ovarian follicles for infertility treatment. Kawamura K 2013 et al. Primary ovarian insufficiency (POI) and polycystic ovarian syndrome are ovarian diseases causing infertility. Although there is no effective treatment for POI, therapies for polycystic ovarian syndrome include ovarian wedge resection or laser drilling to induce follicle growth. Underlying mechanisms for these disruptive procedures are unclear. Here, we explored the role of the conserved Hippo signaling pathway that serves to maintain optimal size across organs and species. We found that fragmentation of murine ovaries promoted actin polymerization and disrupted ovarian Hippo signaling, leading to increased expression of downstream growth factors, promotion of follicle growth, and the generation of mature oocytes. In addition to elucidating mechanisms underlying follicle growth elicited by ovarian damage, we further demonstrated additive follicle growth when ovarian fragmentation was combined with Akt stimulator treatments. We then extended results to treatment of infertility in POI patients via disruption of Hippo signaling by fragmenting ovaries followed by Akt stimulator treatment and autografting. We successfully promoted follicle growth, retrieved mature oocytes, and performed in vitro fertilization. Following embryo transfer, a healthy baby was delivered. The ovarian fragmentation-in vitro activation approach is not only valuable for treating infertility of POI patients but could also be useful for middle-aged infertile women, cancer patients undergoing sterilizing treatments, and other conditions of diminished ovarian reserve./////////Autotransplantation of the ovarian cortex after in-vitro activation for infertility treatment: a shortened procedure. Zhai J et al. (2021) Is it possible to establish a new in-vitro activation (IVA) protocol for infertility treatment? A new IVA procedure is an efficient and easily performed approach for infertility treatment of patients with diminished ovarian reserve (DOR). IVA of primordial follicles with or without stimulators has been developed to treat patients with primary ovarian insufficiency (POI) successfully. However, the efficiency of the procedure is still very low. There is a requirement to optimize the protocol with increased efficiency for clinical application. Newborn mouse ovaries were used to establish a new 1-h IVA protocol with the mechanistic target of rapamycin (mTOR) stimulator phosphatidic acid (PA, 200 µM) and the phosphatidylinositol-3-kinase (PI3K) stimulator 740Y-P (250 µg/ml); a prospective observational cohort study in POI patients was performed on 15 POI patients and 3 poor ovarian response (POR) patients in three different centers of reproductive medicine in China. One-third of ovarian cortex was removed and processed into bigger strips (1 × 1 cm2, 1-2 mm thickness). Strips were then sutured back after treatment. The new approach only requires one laparoscopic surgery. Follicular activation and development increased in cultured mouse and human ovarian tissues after 1 h of stimulator treatment. Compared with tiny ovarian cortex pieces (1 × 1 mm2), large ovarian strips (1 × 1 cm2) showed the lowest apoptotic signals after incubation. We applied the orthotropic transplantation procedure with large strips in the clinic, and 9 of 15 POI patients showed at least one-wave follicular growth during the monitoring period. One patient was reported with one healthy delivery after natural conception and another patient with a healthy singleton delivery after IVF. All the contacted patients (n = 13) responded with no side effects on their health 2-4 years after IVA procedure. Further clinical trials with a large number of well-defined patients are required to compare different IVA protocols. A long-term follow-up system should be set up to monitor patient's health in the future cohort study. By using stimulators, the findings in the study provide a more efficient IVA protocol for the treatment of patients with DOR. It requires only one laparoscopic surgery and thus minimizes patients' discomfort and costs. This strategy could be useful for patients diagnosed with POI and desire pregnancy as soon as possible after the operation. This work was supported by the National Key Research and Development Program of China (2018YFC1003703 and 2018YFC1004203); the National Natural Science Foundation of China (81871221); Co-construction of Provincial Department (201601006). The authors have no conflict of interest to disclose. ChiCTR2000030872.////////////////// //////////In-vitro fragmentation of ovarian tissue activates primordial follicles through the Hippo pathway. De Roo C et al. (2020) What is the role of the Hippo and PI3K/Akt pathway in follicles during ovarian tissue culture in tissue derived from oncological patients and transgender men? Results highlight a Hippo pathway driven primordial follicle activation in vitro, predominantly from Day 0 to Day 4. In-vitro ovarian tissue culture aims at activating and maturing primordial follicles for fertility restoration in patients with a threatened ovarian reserve. Not all patients are eligible for ovarian cortex transplantation and therefore several groups are attempting to culture ovarian tissue in-vitro. Cortex fragmentation disrupts the Hippo pathway, leading to increased expression of downstream growth factors and follicle growth. The PI3K/Akt pathway is considered the intracellular pathway to where different extracellular factors involved in primordial follicle activation in-vivo converge. In order to optimise current ovarian tissue culture models, information on progression of these pathways during tissue culture is mandatory. The first step of a multistep cortex culture system was performed using 144 ovarian cortex pieces from a total of six patients. Per patient, 24 cortical strips were cultured for 6 days and six pieces per patient were collected for downstream analysis of follicle development and Hippo and PI3K/Akt pathway targets every second day. Ovarian tissue was obtained from oncological (N = 3; 28.67 ± 4.51 years) and transgender (N = 3; 23.33 ± 1.53 years) patients. Follicles were analysed using haematoxylin-eosin staining and pathways were studied using immunohistochemistry and precise follicle excision by laser capture micro-dissection for RT-qPCR analysis. MIQE guidelines for RT-qPCR were pursued. Reference gene selection (GAPDH, RPL3A, 18s rRNA) was performed using GeNorm Reference Gene Selection Kit. Statistical analysis was conducted with IBM SPSS Statistics 23 (Poisson regression, negative binomial regression, ANOVA and paired t-test). Immunohistochemical analysis confirmed a Hippo pathway driven primordial follicle activation due to mechanical manipulation of the cortical strips. Ovarian tissue preparation and culture induced the inhibitory phosphorylated Yes-associated protein (pYAP) to disappear in granulosa cells of primordial follicles on Day 2. The stimulatory YAP on the contrary appeared in primordial granulosa cells over increasing culture days. Looking at the YAP target connective tissue growth factor (CTGF), a significantly up-regulated CTGF was noted in primordial follicles when comparing Day 2 and Day 4 (ratio Day 2/4 = 0.082; P < 0.05), clearly showing an effect on the Hippo pathway in primordial follicles during tissue culture. Follicle classification showed a significant drop in estimated primordial follicle counts in the oncological cohort (-78%; P = 0.021) on Day 2 and in the transgender cohort on Day 4 (-634%; P = 0.008). Intermediate follicle counts showed a non-significant increasing trend to during culture and this follicle recruitment and growth resulted in a significant rise in estimated primary follicle counts on Day 6 in oncological patients (170%; P = 0.025) and, although limited in absolute numbers, a significant increase in secondary follicles on Day 4 (367%; P = 0.021) in the transgender cohort. Subsequent antral follicle development could not be observed. A limitation is the small sample size, inherent to this study subject, especially as a large amount of tissue was needed per patient to reduce inter-patient variation in different downstream analysis techniques. A particular and specific weakness of this study is the inability to include an age-matched control group. These findings support an adapted tissue preparation for Hippo pathway disruption and a shorter first phase of tissue culture. This work may also have implications for transplantation of cryopreserved tissue as larger strips (and thus slower burnout due to less Hippo pathway disruption) could be a benefit. This research was financially supported by the Foundation Against Cancer (Stichting tegen Kanker, TBMT001816N), the Flemish Foundation of Scientific Research (FWO Vlaanderen, FWO G0.065.11N10) and the Gender Identity Research and Education Society (GIRES) foundation. The authors declare no competing interests. N/A.////////////////// In vitro activation of ovarian cortex and autologous transplantation: A novel approach to primary ovarian insufficiency and diminished ovarian reserve. Devenutto L et al. (2020) Primary ovarian insufficiency (POI) and diminished ovarian reserve are two conditions that affect women's fertility. Oocyte donation remains an option for these patients; however, the development of certain novel technologies, such as in vitro activation of ovarian cortex (IVA), enables the possibility of activating the pool of resting primordial follicles, increasing the chance of pregnancy. Here, we review the main pathways (PI3K and Hippo signaling) that govern the activation of primordial follicles and its application through the development of culture systems that support ovarian cortex for autologous transplantation. We also review the available data from case reports regarding outcomes of pregnancy and live birth rates with IVA. A PubMed search was conducted using the PubMed-NCBI database to identify literature pertinent to the pathways involved in the activation of primordial follicles and the outcomes of IVA techniques from 2013 to the present. Women with POI have around a 5% chance of spontaneous pregnancy. Recently, novel techniques involving the activation of primordial follicles through molecular pathways have been developed, thus increasing the odds of these patients. More recently, the introduction of a drug-free IVA technique has shown to increase the number of antral follicles with successful oocyte maturation after gonadotropin treatment, reaching pregnancy rates over 30%, either through spontaneous conception or by the implementation of assisted reproductive technology. The evidence of this review is based on a few small series, so data should be interpreted with caution, and only randomized controlled trials could estimate the real magnitude and success of the procedure. IVA technique remains an experimental strategy, with limited available data and the requirement of invasive procedures. Moreover, possible carcinogenic effects not yet determined after transplantation require special caution. In view of the results achieved, IVA could provide a promising option for the preservation of fertility in some cancer patients and prepuberal girls where the only alternative is tissue cryopreservation. The authors received no specific funding for this work and declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article./////Effects of low intensity pulsed ultrasound on expression of B-cell lymphoma-2 and BCL2-Associated X in premature ovarian failure mice induced by 4-vinylcyclohexene diepoxide. Xu H et al. (2021) Premature ovarian failure (POF) is a common disease in the field of Gynecology. Low intensity pulsed ultrasound (LIPUS) can promote tissue repair and improve function. This study was performed to determine the effects of LIPUS on granulosa cells (GCs) apoptosis and protein expression of B-cell lymphoma-2 (Bcl-2) and BCL2-Associated X (Bax) in 4-vinylcyclohexene diepoxide (VCD)-induced POF mice and investigate the mechanisms of LIPUS on ovarian function and reserve capacity. The current POF mice model was administrated with VCD (160 mg/kg) by intraperitoneal injection for 15 consecutive days. The mice were divided into the POF group, LIPUS group and control group. In the LIPUS group, the right ovary of mice was treated by LIPUS (acoustic intensity was 200 mW/cm2, frequency was 0.3 MHz, and duty cycle was 20%) for 20 min, 15 consecutive days from day 16. The mice of the POF group and control group were treated without ultrasonic output. The basic observation and body weight were recorded. Hematoxylin and eosin staining (H&E staining) and enzyme-linked immunosorbent assay (ELISA) were applied to detect ovarian follicle development, ovarian morphology and sex hormone secretion. Ovarian GCs apoptosis was detected by TUNEL assay and immunohistochemistry. The results showed that VCD can induce estrus cycle disorder, follicular atresia, sex hormone secretion decreased and GCs apoptosis in mice to establish POF model successfully. LIPUS significantly promoted follicular development, increased sex hormone secretion, inhibited excessive follicular atresia and GCs apoptosis. The mechanism might be achieved by increasing the protein expression of Bcl-2 and decreasing the expression of Bax in ovaries. LIPUS can improve the POF induced by VCD. These findings have the potential to provide novel methodological foundation for the future research, which help treat POF patients in the clinic./////////////////////Argonaute 2 is a key regulator of maternal mRNA degradation in mouse early embryos. Zhang JM et al. (2020) In mammalian early embryos, the transition from maternal to embryonic control of gene expression requires timely degradation of a subset of maternal mRNAs (MRD). Recently, zygotic genome activation (ZGA)-dependent MRD has been characterized in mouse 2-cell embryo. However, in early embryos, the dynamics of MRD is still poorly understood, and the maternal factor-mediated MRD before and along with ZGA has not been investigated. Argonaute 2 (Ago2) is highly expressed in mouse oocyte and early embryos. In this study, we showed that Ago2-dependent degradation involving RNA interference (RNAi) and RNA activation (RNAa) pathways contributes to the decay of over half of the maternal mRNAs in mouse early embryos. We demonstrated that AGO2 guided by endogenous small interfering RNAs (endosiRNAs), generated from double-stranded RNAs (dsRNAs) formed by maternal mRNAs with their complementary long noncoding RNAs (CMR-lncRNAs), could target maternal mRNAs and cooperate with P-bodies to promote MRD. In addition, we also showed that AGO2 may interact with small activating RNAs (saRNAs) to activate Yap1 and Tead4, triggering ZGA-dependent MRD. Thus, Ago2-dependent degradation is required for timely elimination of subgroups of maternal mRNAs and facilitates the transition between developmental states.///////////////////////////Ovulatory signals alter granulosa cell behavior through YAP1 signaling. Sun T et al. (2020) The Hippo pathway plays critical roles in regulating cell proliferation, differentiation and survival among species. Hippo pathway proteins are expressed in the ovary and are involved in ovarian function. Deletion of Lats1 causes germ cell loss, ovarian stromal tumors and reduced fertility. Ovarian fragmentation induces nuclear YAP1 accumulation and increased follicular development. At ovulation, follicular cells stop proliferating and terminally differentiate, but the mechanisms controlling this transition are not completely known. Here we explore the role of Hippo signaling in mouse granulosa cells before and during ovulation. To assess the effect of oocytes on Hippo transcripts in cumulus cells, cumulus granulosa cells were cultured with oocytes and cumulus oocyte complexes (COCs) were cultured with a pSMAD2/3 inhibitor. Secondly, to evaluate the criticality of YAP1 on granulosa cell proliferation, mural granulosa cells were cultured with oocytes, YAP1-TEAD inhibitor verteporfin or both, followed by cell viability assay. Next, COCs were cultured with verteporfin to reveal its role during cumulus expansion. Media progesterone levels were measured using ELISA assay and Hippo transcripts and expansion signatures from COCs were assessed. Lastly, the effects of ovulatory signals (EGF in vitro and hCG in vivo) on Hippo protein levels and phosphorylation were examined. Throughout, transcripts were quantified by qRT-PCR and proteins were quantified by immunoblotting. Data were analyzed by student's t-test or one-way ANOVA followed by Tukey's post-hoc test or Dunnett's post-hoc test. Our data show that before ovulation oocytes inhibit expression of Hippo transcripts and promote granulosa cell survival likely through YAP1. Moreover, the YAP1 inhibitor verteporfin, triggers premature differentiation as indicated by upregulation of expansion transcripts and increased progesterone production from COCs in vitro. In vivo, ovulatory signals cause an increase in abundance of Hippo transcripts and stimulate Hippo pathway activity as indicated by increased phosphorylation of the Hippo targets YAP1 and WWTR1 in the ovary. In vitro, EGF causes a transient increase in YAP1 phosphorylation followed by decreased YAP1 protein with only modest effects on WWTR1 in COCs. Our results support a YAP1-mediated mechanism that controls cell survival and differentiation of granulosa cells during ovulation.////////////////// Interaction between PI3K/AKT and Hippo pathways during in vitro follicular activation and response to fragmentation and chemotherapy exposure using a mouse immature ovary model. Devos M et al. (2019) Understanding and control of the massive and accelerated follicular growth that occurs during in vitro culture of ovarian tissue is a crucial step toward the development of efficient culture systems that offer an attractive alternative to ovarian tissue transplantation for fertility restoration in cancer survivors. One outstanding question focuses on processes that occur prior to cryopreservation, such as tissue sectioning or chemotherapeutic treatment, that might exacerbate this follicular activation. While the PI3K/AKT/mTOR pathway is well-known as a major trigger of physiological and chemotherapy-induced follicular activation, studies have shown that disruption of Hippo pathway due to ovarian fragmentation acts as an additional stimulator. This study aimed to characterize the possible interactions between these pathways using post-natal day 3 mouse ovaries cultured for 4 or 48 h. Morphology, gene transcription, and protein levels were assessed to investigate the impact of sectioning or chemotherapy exposure (4-hydroperoxycyclophosphamide [4HC], 3 and 20 μM). The effect of an mTORC1 inhibitor, Everolimus, alone or as a 4HC co-treatment to prevent follicle activation was evaluated. The results showed that organ removal from its physiological environment was as effective as sectioning for disruption of Hippo pathway and induction of follicle activation. Both PI3K/AKT/mTOR and Hippo pathways were involved in chemotherapy-induced follicular activation and responded to fragmentation. Surprisingly, Everolimus was able to prevent the activation of both pathways during chemotherapy exposure, suggesting cross-talk between them. This study underscores the major involvement of PI3K/AKT/mTOR and Hippo pathways in in vitro follicle activation and provides evidence that both can be regulated using mTORC1 inhibitor.////////////////// . Yes-associated protein (YAP1) is required for proliferation and function of bovine granulosa cells in vitro$. Plewes MR et al. (2019) Yes-associated protein (YAP1) is a major component of the Hippo signaling pathway. Although the exact extracellular signals that control the Hippo pathway are currently unknown, increasing evidence supports a critical role for the Hippo pathway in embryonic development, regulation of organ size, and carcinogenesis. Granulosa cells within the ovarian follicle proliferate and produce steroids and growth factors, which facilitate growth of follicle and maturation of the oocyte. We hypothesize that YAP1 plays a role in proliferation and estrogen secretion of granulosa cells. In the current study, we examined expression of the Hippo signaling pathway in bovine ovaries and determined whether it was important for granulosa cell proliferation. MST1 and LATS2 were identified as prominent upstream components of the Hippo pathway expressed in granulosa and theca cells of the follicle and large and small cells of the corpus luteum. Immunohistochemistry revealed that YAP1 was localized to the nucleus of growing follicles. In vitro, nuclear localization of the downstream Hippo signaling effector proteins YAP1 and TAZ (WWTR1) was inversely correlated with granulosa cell density, with greater nuclear localization under conditions of low cell density. Treatment with verteporfin and siRNA targeting YAP1 or TAZ revealed a critical role for these transcriptional co-activators in granulosa cell proliferation. Furthermore, knockdown of YAP1 in granulosa cells inhibited FSH-induced estradiol biosynthesis. The data indicate that Hippo pathway transcription co-activators YAP1/TAZ play an important role in granulosa cell proliferation and estradiol synthesis, two processes necessary for maintaining normal follicle development.//////////////////Hippo pathway functions as a downstream effector of AKT signaling to regulate the activation of primordial follicles in mice. Hu LL et al. (2018) Clarifying the molecular mechanisms by which primordial follicles are initiated is crucial for the prevention and treatment of female infertility and ovarian dysfunction. The Hippo pathway has been proven to have a spatiotemporal correlation with the size of the primordial follicle pool in mice in our previous work. But the role and underlying mechanisms of the Hippo pathway in primordial follicle activation remain unclear. Here, the localization and expression of the core components were examined in primordial follicles before and after activation. And the effects of the Hippo pathway on primordial follicle activation were determined by genetically manipulating yes-associated protein 1 (Yap1), the key transcriptional effector. Furthermore, an AKT specific inhibitor (MK2206) was added to determine the interaction between the Hippo pathway and AKT, an important signaling regulator of ovarian function. Results showed that the core components of the Hippo pathway were localized in both primordial and primary follicles and the expression levels of them changed significantly during the initiation of primordial follicles. Yap1 knockdown suppressed primordial follicle activation, while its overexpression led to the opposite trend. MK2206 downregulated the ratio of P-MST/MST1 and upregulated the ratio of P-YAP1/YAP1 significantly, whereas Yap1-treatment had no influence on AKT. In addition, YAP1 upregulation partially rescued the suppression of the primordial follicle activation induced by MK2206. Our findings revealed that the Hippo-YAP1 regulates primordial follicular activation, which is mediated by AKT signaling in mice, thus providing direct and new evidence to highlight the role of Hippo signaling in regulating ovarian follicles development.////////////////// /////////////////////////Dynamics of PI3K and Hippo signaling pathways during in vitro human follicle activation. Grosbois J et al. (2018) How does biochemical stimulation or inhibition of the PI3K/Akt/mTOR pathway affect the activation and the growth of human primordial follicles in vitro? The PI3K/Akt activators act synergistically with the Hippo signaling pathway, disrupted by tissue fragmentation, to accelerate primordial follicles recruitment while mTORC1 inhibitor partially prevents the massive spontaneous activation. Hippo disruption caused by ovarian fragmentation and exposure to PI3K/Akt activators have been successfully used to activate resting follicles prior to grafting in patients with premature ovarian insufficiency. Outside this indication, massive and premature activation is considered deleterious as it leads to the depletion of the follicular pool and developmental defects in vitro. One hundred and twelve frozen-thawed ovarian cortex fragments from four patients were exposed to dimethylsulfoxide (DMSO-control group), everolimus (inhibitor group) or bpV (HOpic) and 740Y-P (activators group) during the first 24 and 48 h, respectively, and cultured for additional 5 days. The ovarian fragments (4×2×1 mm3) were analyzed at Days 0, 1, 3 and 5 of culture. Cortex were either directly processed for immunohistological or western blot analysis or subjected to follicular isolation for assessment of gene expression. The follicle number and the developmental stage were evaluated in sections of ovarian fragments to assess the early follicular development. Survival and developmental potential were evaluated using TUNEL labeling, GDF9 and Ki67 immunostainings, Kit ligand mRNA relative expression and measurement of 17β-estradiol (E2) levels in the culture medium. qPCR and western blotting were used to explore the expression of PI3K/Akt and Hippo pathways (TSC1, mTOR, LATS1, BIRC1 and CCN2 genes and PTEN/p-PTEN, Akt/p-Akt and rpS6/p-rps6 proteins), and localization of YAP in human ovarian tissue was performed by immunofluorescence. Around 80% of the follicles spontaneously activated during the culture period, triggered by the activation of the PI3K/Akt/mTOR signaling. Moreover, ovarian fragmentation immediately promoted translocation of the Hippo effector YAP into the nucleus of granulosa cells, leading to upregulation of BIRC1 and CCN2 downstream targets at Day 0 and an increase of follicular growth near the cutting site. Short term exposure of thawed human ovarian fragments to PI3K/Akt activators had significant (P < 0.05 at D1 and D3; P < 0.001 at D6) but limited and potentially negative effects on follicular activation compared to spontaneous follicular growth as suggested by impaired E2 secretion. In contrast, transient incubation with an mTORC1 inhibitor partially prevented spontaneous activation by limiting growing follicle counts (P < 0.01 at D6), granulosa cell proliferation, and Kit ligand expression while ensuring appropriate steroidogenesis. N/A. Impact of in vitro culture might cover up the potential benefit of the everolimus on growing follicles morphology after 6 days. Our results demonstrate the synergistic effects of Hippo and PI3K/Akt/mTOR signaling, contributing to the acceleration of early primordial follicle recruitment in thawed human ovarian fragments, and suggest a beneficial effect of the mTORC1 inhibitor. This work was supported by a grant from the Fond National de la Recherche Scientifique de Belgique (Grant Télevie Nos. 7.6516.16 F and 7.4578.14 F) and the Fonds Erasme. No competing interests declared.////////////////// Role of Yes-Associated Protein 1, Angiomotin and Mitogen Activated Kinase Kinase 1/2 in Development of the Bovine Blastocyst. Negrón-Pérez VM et al. (2017) The morula-stage embryo is transformed into a blastocyst composed of epiblast, hypoblast and trophectoderm (TE) through mechanisms that, at least in the mouse, involve the Hippo signaling and mitogen-activated kinase (MAPK) pathways. Using the cow as an additional model, we tested the hypotheses that TE and hypoblast differentiation were regulated by the Hippo pathway regulators, YAP1 and AMOT, and MAPK kinase 1/2 (MAPK1/2). The presence of YAP1 and CDX2 in the nucleus and cytoplasm of MII oocytes and embryos was evaluated by immunofluorescence labeling. For both molecules, localization changed from cytoplasmic to nuclear as development advanced. Inhibition of YAP1 activity, either by verteporfin or a YAP1- targeting GapmeR, reduced the percent of zygotes that became blastocysts, the proportion of blastocysts that hatched and numbers of CDX2+ cells in blastocysts. Moreover, the YAP1- targeting GapmeR altered expression of 15 of 91 genes examined in the day 7.5 blastocyst. Treatment of embryos with an AMOT targeting GapmeR did not affect blastocyst development or hatching but altered expression of 16 of 91 genes examined at day 7.5 and reduced the number of CDX2+ nuclei and YAP1+ nuclei in blastocysts at day 8.5 of development. Inhibition of MAPK1/2 with PD0325901 did not affect blastocyst development but increased the number of epiblast cells. Results reported here are indicative of a role of YAP1 and AMOT in function of TE in the bovine blastocyst. YAP1 can also affect function of the epiblast and hypoblast and MAPK signaling is important for ICM differentiation by reducing epiblast numbers.//////////////////Stein and Leventhal: 80 Years On. Azziz R et al. (2015) Eighty years ago a publication in this journal proved to be seminal and transformative. The report By Irving Freiler Stein and Michael Leventhal titled "Amenorrhea Associated with Polycystic Ovaries" has proven to be a remarkably lasting and influential publication. The growth in related literature has been increasing exponentially: the 50 years between 1950 and 2000 saw a little over 8000 publications on the topic, while the 15 year period between 2001 and 2015 (so far) has seen over 20,000 related publications, a greater than 8-fold increase in publication rate post-2000. As we commemorate the 80(th) anniversary year of the publication of the report by Stein and Leventhal, it is important to ask ourselves….Was this publication truly as seminal as it is generally assumed to be? And why did it gain such a strong foothold on the medical psyche? To the first question a review of the antecedent medical literature makes it clear that the report of Drs. Stein and Leventhal in 1935, while not flawless, was both seminal and transformative. In fact, it was the first report to describe a series of patients, rather than isolated cases, who demonstrated the triad of polycystic ovaries, hirsutism, and oligo/amenorrhea, connecting what had previously been disparate features of polycystic ovaries and menorrhagia, and hirsutism and oligo/amenorrhea. Secondly, the facts that Dr. Stein and his collaborators were relatively prolific writers, consistent and clear in their message and descriptions; that a possible therapy (bilateral ovarian wedge resection) had been conveniently included in the report; and that the disorder was (is) relatively prevalent, permitted what would eventually be called the Stein-Leventhal syndrome to gain a strong foothold in contemporary medical practice. Overall, we in the field of medicine have much to celebrate, as we commemorate the 80th anniversary of the publication of the report by Stein and Leventhal in 1935, for a new disorder was described, one that we know today affects, in its various forms, one in every 7 to 17 women worldwide./////////////////Oocyte-expressed yes-associated protein is a key activator of the early zygotic genome in mouse. Yu C et al. (2016) In early mammalian embryos, the genome is transcriptionally quiescent until the zygotic genome activation (ZGA) which occurs 2-3 days after fertilization. Despite a long-standing effort, maternal transcription factors regulating this crucial developmental event remain largely elusive. Here, using maternal and paternal mouse models of Yap1 deletion, we show that maternally accumulated yes-associated protein (YAP) in oocyte is essential for ZGA. Maternal Yap1-knockout embryos exhibit a prolonged two-cell stage and develop into the four-cell stage at a much slower pace than the wild-type controls. Transcriptome analyses identify YAP target genes in early blastomeres; two of which, Rpl13 and Rrm2, are required to mediate maternal YAP's effect in conferring developmental competence on preimplantation embryos. Furthermore, the physiological YAP activator, lysophosphatidic acid, can substantially improve early development of wild-type, but not maternal Yap1-knockout embryos in both oviduct and culture. These observations provide insights into the mechanisms of ZGA, and suggest potentials of YAP activators in improving the developmental competence of cultured embryos in assisted human reproduction and animal biotechnology.////////////////// | ||||
| Expression regulated by | FSH, LH, Steroids, S1P, androgen, estrogen | ||||
| Comment | Deficiency of Pdk1 contributes to primordial follicle activation via the upregulation of YAP expression and the pro‑inflammatory response. Gao J et al. (2020) The molecular mechanisms underlying the activation of primordial follicles are poorly understood. The serine/threonine protein kinase phosphoinositide‑dependent kinase 1 (PDK1), a pivotal downstream effector of phosphatidyl inositol‑3 kinase (PI3K) signaling, plays a vital role in cellular signaling. In order to identify the function of PDK1 in ovarian follicle development, this study used conditional Pdk1 deletion in mouse oocytes by crossing Pdk1loxP/loxP mice with transgenic mice carrying Gdf‑9 promoter‑mediated Cre recombinase and found that Pdk1flx/flxGdf9Cre mice were subfertile with increased serum follicle‑stimulating hormone (FSH) and luteinizing hormone (LH) levels compared with Pdk1flx/flx mice. The deletion of Pdk1 in oocytes induced massive primordial follicle activation, leading to premature ovarian failure (POF). Further investigation revealed that enhanced Yes‑associated protein (YAP) expression and an increased pro‑inflammatory response also contributed to massive primordial follicle activation. PDK1 formed the complex with the core kinases of Hippo signaling and regulated the expression levels of YAP. On the whole, the findings of the present study demonstrate that PDK1 serves as an indispensable gatekeeper for maintaining the primordial follicle pool and provide a deeper understanding of POF treatment.////////////////// The Polycystic Ovary Syndrome-associated Gene Yap1 is Regulated by Gonadotropins and Sex Steroid Hormones in Hyperandrogenism-induced Oligo-ovulation in Mouse. Ji SY et al. (2017) What is the physiological function of Yes-associated protein-1 (Yap1), a susceptibility gene for polycystic ovarian syndrome (PCOS), in ovarian granulosa cells? Physiologically, steroid sex hormones stimulate follicle growth by activating YAP1; however, the preovulatory inhibition of YAP1 activity in granulosa cells is a prerequisite of LH actions. PCOS is a common gynecologic and endocrine disease with multiple short and long-term consequences. Many PCOS patients suffer anovulation caused by hyperandrogenism, but its etiology remains unclear. To study the effect of acute hyperandrogenism on ovulation, we injected pregnant mare serum gonadotrophin (PMSG)-primed (44 h) pubertal mice with dihydrotestosterone (DHT), the major biologically active form of androgen, in a superovulation assay. We investigated if YAP1 is regulated by testosterone and if it is potentially involved in follicle development and ovulation. Cultured primary granulosa cells were subjected to Yap1 depletion by RNA interference and Yap1 overexpression by adenoviral infections. Female mice at postnatal day (PD)-21~23 were analyzed to avoid the complexity of ovarian functions associated with estrous cycles and endogenous surges of gonadotropins. Immature mice were injected intraperitoneally with 5 IU PMSG to stimulate preovulatory follicle development followed 44 h later with 5 IU hCG to stimulate ovulation. For DHT treatments, female mice at PD23 were injected intraperitoneally with 5 IU PMSG followed 44 h later with 5 IU hCG alone (as control) or 5 IU hCG plus 100 μg DHT, which was dissolved in 0.1 ml DMSO. Methods of gene expression detection used include immunohistochemistry, immunofluorescence, Western blotting, and quantitative PCR. More than 3 biological and technical replicates were included in each experiments. we provide novel evidence in a mouse model that YAP1 is required for proliferation of ovarian granulosa cells, but is downregulated by luteinizing hormone (LH) through the extracellular-regulated kinase-1/2 (ERK1/2) cascade. Acute hyperandrogenism blocks LH actions and causes oligo-ovulation by activating YAP1. N/A. Results shown were obtained only in mouse, and need to be further confirmed in human samples. These findings not only elucidated the role of YAP1 in maintaining normal ovarian functions, but also link the YAP1 deregulation to the pathogenesis of PCOS. This study is funded by the National Key Research and Development Program of China (2016YFC1000600, 2017YFSF1001500) and National Natural Science Foundation of China (31528016, 31371449, 31671558). The authors have no competing interests.////////////////// Protein Kinase A: A Master Kinase of Granulosa Cell Differentiation. Puri P et al. (2016) Activation of protein kinase A (PKA) by follicle stimulating hormone (FSH) transduces the signal that drives differentiation of ovarian granulosa cells (GCs). An unresolved question is whether PKA is sufficient to initiate the complex program of GC responses to FSH. We compared signaling pathways and gene expression profiles of GCs stimulated with FSH or expressing PKA-CQR, a constitutively active mutant of PKA. Both FSH and PKA-CQR stimulated the phosphorylation of proteins known to be involved in GC differentiation including CREB, ß-catenin, AKT, p42/44 MAPK, GAB2, GSK-3ß, FOXO1, and YAP. In contrast, FSH stimulated the phosphorylation of p38 MAP kinase but PKA-CQR did not. Microarray analysis revealed that 85% of transcripts that were up-regulated by FSH were increased to a comparable extent by PKA-CQR and of the transcripts that were down-regulated by FSH, 76% were also down-regulated by PKA-CQR. Transcripts regulated similarly by FSH and PKA-CQR are involved in steroidogenesis and differentiation, while transcripts more robustly up-regulated by PKA-CQR are involved in ovulation. Thus, PKA, under the conditions of our experimental approach appears to function as a master upstream kinase that is sufficient to initiate the complex pattern of intracellular signaling pathway and gene expression profiles that accompany GC differentiation.////////////////// Sphingosine-1-phosphate induces COX-2 expression and PGE2 production in human granulosa cells through a S1P1/3-mediated YAP signaling. Cheng JC et al. (2016) Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that can regulate various physiological and pathological processes. The expression of S1P has been detected in human follicular fluid. In addition, two S1P receptors, S1P1 and S1P3, are expressed at a high level in human granulosa cells. Cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) production plays a critical role in the regulation of ovulation. However, thus far, the effect of S1P on COX-2 expression and PGE2 production in human granulosa cells remains unknown. In the present study, our results demonstrated that treatment with S1P significantly induced COX-2, but not COX-1, expression and increased PGE2 production in human granulosa cells. The stimulatory effects of S1P on COX-2 expression and PGE2 production were attenuated by treatment with specific antagonist of S1P1 or S1P3 and siRNA-mediated knockdown of S1P1 or S1P3. In addition, the COX-2 expression was induced by S1P1 or S1P3 agonist treatment. Interestingly, treatment with S1P activated YAP signaling via S1P1 and S1P3. Moreover, knockdown of YAP partially attenuated S1P-induced COX-2 expression and PGE2 production. These results provide evidence that S1P induces COX-2 expression and PGE2 production in human granulosa cells through a S1P1/3-mediated YAP signaling pathway.////////////////// Gene expression decreased. Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression. Agca C et al. The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (n = 11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; n = 6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; n = 5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P<0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function. YAp1 showed expression decreases (11-fold change) from preovulatory estrogenic to preovulatory luteinized granulosa cells. | ||||
| Ovarian localization | Oocyte, Granulosa, Luteal cells, Ovarian tumor | ||||
| Comment | The Hippo Signaling Pathway Regulates Ovarian Function via the Proliferation of Ovarian Germline Stem Cells. Ye H et al. (2017) To improve the separation, identification and cultivation of ovarian germline stem cells (OGSCs), to clarify the relationship between the Hippo signaling pathway effector YAP1 and the proliferation and differentiation of OGSCs in vitro and to identify the major contribution of Hippo signaling to ovarian function. Two-step enzymatic separation processes and magnetic separation were used to isolate and identify OGSCs by determining the expression of Mvh, Oct4, Nanog, Fragilis and Stella markers. Then, YAP1, as the main effector molecule in the Hippo signaling pathway, was chosen as the target gene of the study. Lentivirus containing overexpressed YAP1 or a YAP1-targeted shRNA was transduced into OGSCs. The effects of modulating the Hippo signaling pathway on the proliferation, differentiation, reproduction and endocrine function of ovaries were observed by microinjecting the lentiviral vectors with overexpressed YAP1 or YAP1 shRNA into infertile mouse models or natural mice of reproductive age. (1) The specific expression of Mvh, Oct4, Nanog, Fragilis and Stella markers was observed in isolated stem cells. Thus, the isolated cells were preliminarily identified as OGSCs. (2) The co-expression of LATS2, MST1, YAP1 and MVH was observed in isolated OGSCs. Mvh and Oct4 expression levels were significantly increased in OGSCs overexpressing YAP1 compared to GFP controls. Consistently, Mvh and Oct4 levels were significantly decreased in cells expressing YAP1-targeted shRNA. (3) After 14-75 days of YAP1 overexpression in infertile mouse models, we detected follicle regeneration in ovaries, the activation of primordial follicles and increased birth rate, accompanied by increasing levels of E2 and FSH. (4) However, we detected decreasing follicles in ovaries, lower birth rate, and decreasing E2 and FSH in serum from healthy mice of reproductive age following YAP1 shRNA expression. Methods for the isolation, identification and culture of OGSCs were successfully established. Further results indicate that isolated OGSCs can specifically recognize Hippo signaling molecules and that manipulation of YAP1 expression can be used to regulate the proliferation and differentiation of OGSCs, as well as ovarian function in mice. This study suggests that the Hippo signaling pathway may represent a new molecular target for the regulation of mouse ovarian functional remodeling.////////////////// Multiple Mechanisms Cooperate to Constitutively Exclude the Transcriptional Co-Activator YAP from the Nucleus During Murine Oogenesis. Abbassi L et al. (2016) Reproduction depends on the generation of healthy oocytes. Improving therapeutic strategies to prolong or rescue fertility depends on identifying the inter- and intracellular mechanisms that direct oocyte development under physiological conditions. Growth and proliferation of multiple cell types is regulated by the Hippo signaling pathway, whose chief effectors are the transcriptional co-activator YAP and its paralogue, WWTR1. To resolve conflicting results concerning the potential role of Hippo in mammalian oocyte development, we systematically investigated the expression and localization of YAP in mouse oocytes. We report that that YAP is expressed in the germ cells beginning as early as Embryonic Day-15.5 and subsequently throughout pre- and post-natal oocyte development. However, YAP is restricted to the cytoplasm at all stages. YAP is phosphorylated at serine-112 in growing and fully grown oocytes, identifying a likely mechanistic basis for its nuclear exclusion, and becomes dephosphorylated at this site during meiotic maturation. Phosphorylation at serine-112 is regulated by a mechanism dependent on cyclic AMP and protein kinase A, which is known to be active in oocytes prior to maturation. Growing oocytes also contain a sub-population of YAP, likely dephosphorylated, that is able enter the oocyte nucleus, but it is not retained there, implying that oocytes lack the co-factors required to retain YAP in the nucleus. Thus, although YAP is expressed throughout oocyte development, phosphorylation-dependent and -independent mechanisms cooperate to ensure that it does not accumulate in the nucleus. We conclude that nuclear YAP does not play a significant physiological role during oocyte development in mammals.////////////////// YAP Promotes Ovarian Cancer Cell Tumorigenesis and Is Indicative of a Poor Prognosis for Ovarian Cancer Patients. Xia Y 2014 et al. YAP is a key component of the Hippo signaling pathway and plays a critical role in the development and progression of multiple cancer types, including ovarian cancer. However, the effects of YAP on ovarian cancer development in vivo and its downstream effectors remain uncertain. In this study we found that strong YAP expression was associated with poor ovarian cancer patient survival. Specifically, we showed for the first time that high YAP expression levels were positively correlated with TEAD4 gene expression, and their co-expression was a prognostic marker for poor ovarian cancer survival. Hyperactivation of YAP by mutating its five inhibitory phosphorylation sites (YAP-5SA) increased ovarian cancer cell proliferation, resistance to chemotherapeutic drugs, cell migration, and anchorage-independent growth. In contrast, expression of a dominant negative YAP mutant reversed these phenotypes in ovarian cancer cells both in vitro and in vivo. Our results suggested that YAP caused these effects by promoting an epithelial-to-mesenchymal transition. Thus, YAP promotes ovarian cancer cell growth and tumorigenesis both in vitro and in vivo. Further, high YAP and TEAD4 expression is a prognostic marker for ovarian cancer progression and a potential target for ovarian cancer treatment. ///////////////////////// Activation of YAP1 Is Associated with Poor Prognosis and Response to Taxanes in Ovarian Cancer. Jeong W 2014 et al. UNLABELLED Aim: We aimed to investigate the clinical significance of the activation of Yes-Associated Protein 1 (YAP1), a key downstream effector of Hippo tumor-suppressor pathway, in ovarian cancer. MATERIALS AND METHODS A gene expression signature reflecting activation of YAP1 was developed from gene expression data of 267 samples from patients with ovarian cancer. A refined ovarian cancer YAP1 signature was validated in an independent ovarian cancer cohort (n=185). Associations between the YAP1 signature and prognosis were assessed using Kaplan-Meier plots, the log-rank test, and a Cox proportional hazards model. RESULTS We identified a 612-gene expression signature reflecting YAP1 activation in ovarian cancer. In multivariate analysis, the signature was an independent predictor of overall survival (hazard ratio=1.66; 95% confidence interval=1.1 to 2.53; p=0.01). In subset analysis, the signature identified patients likely to benefit from taxane-based adjuvant chemotherapy. CONCLUSION Activation of YAP1 is significantly associated with prognosis and the YAP1 signature can predict response to taxane-based adjuvant chemotherapy in patients with ovarian cancer. ///////////////////////// Ovarian Germline Stem Cells (OGSCs) and the Hippo Signaling Pathway Association with Physiological and Pathological Ovarian Aging in Mice. Li J et al. (2015) The Hippo signaling pathway plays fundamental roles in stem cell maintenance in a variety of tissues and has thus implications for stem cell biology. Key components of this recently discovered pathway have been shown to be associated with primordial follicle activation. However, whether the Hippo signaling pathway plays a role in the development of Ovarian Germline Stem Cells (OGSCs) during physiological and pathological ovarian aging in mice is unknown. Mice at the age of 7 days (7D), or of 2, 10, or 20 months (2M, 10M, 20M) and mice at 2M treated with TPT and CY/BUS drugs were selected as physiological and pathological ovarian aging models, respectively. Immunohistochemistry was used to assess the development of follicles, and the co-localization of genes characteristic of OGSCs with MST1, LATS2 and YAP1 was assessed by immunofluorescence, western blotting and real-time PCR methods. The Hippo signal pathway and MVH/OCT4 genes were co-expressed in the mouse ovarian cortex. The level and co-localization of LATS2, MST1, MVH, and OCT4 were significantly decreased with increased age, but YAP1 was more prevalent in the mouse ovarian cortex of 2M mice than 7D mice and was not observed in 20M mice. Furthermore, YAP1, MVH, and OCT4 were gradually decreased after TPT and CY/BUS treatment, and LATS2 mRNA and protein up-regulation persisted in TPT- and CY/BUS-treated mice. However, the expression of MST1 was lower in the TPT and CY/BUS groups compared with the control group. In addition, pYAP1 protein showed the highest expression in the ovarian cortexes of 7D mice compared with 20M mice, and the value of pYAP1/YAP1 decreased from 7D to 20M. Moreover, pYAP1 decreased in the TPT- and CY/BUS-treated groups, but the value of pYAP1/YAP1 increased in these groups. Taken together, our results show that the Hippo signaling pathway is associated with the changes that take place in OGSCs during physiological and pathological ovarian aging in mice. Thus, the Hippo signaling pathway may be involved in the development schedule of OGSCs. © 2015 S. Karger AG, Basel.////////////////// The Hippo Pathway Effector, Yap, is an Ovarian Cancer Oncogene. Hall CA et al. The Hippo Pathway regulates organ size and tumorigenesis in Drosophila and mammals and is altered in a variety of human cancers, yet it remains unclear if the Hippo Pathway is of prognostic significance to cancer patients. Here we show that Yap, the human homolog of the key transcriptional target of the Hippo pathway, plays a conserved role in promoting tumorigenesis in both the fly ovary and human ovarian cancer. While studies linking Yap to cancer in other tissues have focused on overall Yap levels, we demonstrate for the first time that subcellular levels of Yap show an exceptionally strong association with poor patient survival. Specifically, high levels of nuclear Yap, or low levels of cytoplasmic phosphorylated-Yap, associated with poor survival from ovarian cancer. Patients with both high nuclear Yap and low cytoplasmic phosphorylated-Yap had approximately 50% lower 5-year survival, and this combination is an independent prognostic marker for survival, with an exceptionally high hazard ratio of 7.8. Further, overexpression of Yap and phosphorylation-defective Yap-5A in immortalized ovarian surface epithelium cells resulted in increased cell proliferation, resistance to cisplatin-induced apoptosis, faster cell migration, and anchorage independent growth, while Yap knockdown resulted in increased sensitivity to cisplatin-induced apoptosis. Together, our results indicate that Hippo signaling is likely to define a novel pathway in ovarian cancer.//////////YAP regulates cell proliferation, migration, and steroidogenesis in adult granulosa cell tumors. Fu D 2014 et al. The Hippo signaling pathway has been implicated as a conserved regulator of organ size in both Drosophila and mammals. Yes associated protein (YAP), the central component of the Hippo signaling cascade, functions as an oncogene in several malignancies. Ovarian granulosa cell tumors (GCT) are characterized by enlargement of ovary, excess production of estrogen, high frequency of recurrence and potential of malignancy and metastasis. Whether the Hippo pathway plays a role in the pathogenesis of GCT is unknown. This study was conducted to examine the expression of YAP in human adult GCTs and to determine the role of YAP in the proliferation and steroidogenesis of GCT cells. Compared with age-matched normal human ovaries, GCT tissues exhibited higher levels of YAP expression. YAP protein was predominantly expressed in the nucleus of tumor cells, whereas the non-tumor ovarian stromal cells expressed very low levels of YAP. YAP was also expressed in cultured primary | ||||
| Follicle stages | Primordial, Primary, Secondary, Antral | ||||
| Comment | Hippo signaling pathway reveals a spatio-temporal correlation with the size of primordial follicle pool in mice. Xiang C et al. (2015) The Hippo signaling pathway, a highly conserved cell signaling system, exists in most multicellular organisms and regulates cell proliferation, differentiation, and apoptosis. It has been reported that the members of Hippo signaling are expressed in mammalian ovaries, but the exact functions of this pathway in primordial follicle development remains unclear. To analyze the spatio-temporal correlation between the core component of Hippo pathway and the size of primordial follicle pool, Western blot, Real-time PCR and immunohistochemistry were used, and the expression and localization of MST1, LATS2 and YAP1 mRNA and protein were examined in 3 d, 1 m, 5 m, 16 m postnatal mice ovary and the culture model of mice primordial follicle in vitro. Both the protein and mRNA expression of the MST1 and LATS2 were decreased significantly as mouse age increased (p < 0.05), however, the mRNA expression of them increased significantly in 16 m compared with 5 m as well as the protein expression of LATS2.The expression of YAP showed the opposite trend, and the significant protein expression of pYAP was increased before 1 m, after which no significant change was observed. Moreover, the ratio of pYAP/YAP decreased significantly. Culturing ovaries for 8 d in vitro resulted in the activation of primordial follicles in 3 d postnatal mice ovaries, and these developed into primary follicles with the expression of PCNA increasing significantly (p < 0.05). The mRNA and protein expression of MST and LATS decreased significantly (p < 0.05), and the expression of YAP increased significantly (p < 0.05, p < 0.01), whereas the ratio of pYAP/YAP decreased significantly (p < 0.05). The above results reveal that the expression of the core components of Hippo pathway changed during mouse follicular development, especially before and after primordial follicle activation in vitro. The primordial follicle activation may be related to the significant decrease of the ratio of pYAP1/YAP1. In conclusion, Hippo signaling pathway expressed in mice ovaries and have spatio-temporal correlation with the size of primordial follicle pool. © 2015 S. Karger AG, Basel.////////////////// | ||||
| Phenotypes |
PCO (polycystic ovarian syndrome) |
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| Mutations |
9 mutations
Species: human
Species: human
Species: human
Species: mouse
Species: mouse
Species: mouse
Species: mouse
Species: human
Species: human
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| Genomic Region | show genomic region | ||||
| Phenotypes and GWAS | show phenotypes and GWAS | ||||
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| created: | July 20, 2006, 1:35 p.m. | by: |
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| last update: | July 23, 2021, 3:05 p.m. | by: | hsueh email: |
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