Protective effects ROS up-regulation on premature ovarian failure by suppressing ROS-TERT signal pathway.

OBJECTIVE: Premature ovarian failure (POF) refers to the condition of pre-onset ovarian function failure, and is one commonly occurred disease in gynecology. Its pathogenic mechanism, however, is still unclear. Early study found decreased activity of telomerase reverse transcriptase (TERT). As an important factor to suppress TERT, oxidative stress has not been studied in POF. We, thus, investigated the role of reactive oxygen species (ROS)-TERT in POF. MATERIALS AND METHODS: Rat POF model was induced by a single intraperitoneal injection of cyclophosphamide plus 12 mg/kg busulfan. Level of follicle stimulating hormone (FSH) and inhibin B was measured by enzyme-linked immunosorbent assay (ELISA), along with hematoxylin and eosin (HE) staining to confirm successful generation of models. Western blot was applied to measure TERT expression, and N-acetyl-cysteine (NAC) or TERT small interfere RNA (siRNA) was injected to suppress ROS or TERT level, followed by HE staining to observe POF condition. RESULTS: In POF model, ovary tissues showed atrophy, less follicles, and more follicular atresia, plus mesenchymal hyperplasia. FSH and inhibin B level were significantly up-regulated and down-regulated, respectively (p<0.05). In POF rat, ROS level was elevated (p<0.05) whilst TERT level was decreased. NAC inhibited ROS level and enhanced TERT expression. In contrast, TERT siRNA further aggravated POF condition. CONCLUSIONS: ROS up-regulation inhibits TERT expression, suppresses TERT activity and facilitates POF. The ROS-TERT pathway may work as the target for treating POF.

Regulation of follicle growth through hormonal factors and mechanical cues mediated by Hippo signaling pathway.

The ovary is an interesting organ that shows major structural changes within a short period of time during each reproductive cycle. Follicle development is controlled by local paracrine and systemic endocrine factors. Many hormonal and molecular analyses have been conducted to find the mechanisms underlying structural changes in ovaries, However, exact mechanisms still remain to be determined. Recent development of mechanobiology facilitates the understanding on the contribution of physical forces and changes in the mechanical properties of cells and tissues to physiology and pathophysiology. The Hippo signaling pathway is one of the key players in mechanotransduction, providing an understanding of the molecular mechanisms by which cells sense and respond to mechanical signals to regulate cell proliferation and apoptosis for maintaining optimal organ sizes. Our group recently demonstrated the involvement of the Hippo signaling pathway in the regulation of ovarian follicle development. Fragmentation of ovarian cortex into small cubes changed cytoskeletal actin dynamics and induced disruption of the Hippo signaling pathway, leading to the production of CCN growth factors and anti-apoptotic BIRC. These factors, in turn, stimulated secondary follicle growth in vitro and in vivo. In this review, we summarized hormonal regulation of follicular structural changes and further focused on the role of Hippo signaling in the regulation of follicle development. We also suggest a new strategy of infertility treatments in patients with polycystic ovary syndrome and primary ovarian insufficiency based on mechanobiology.

[Effects of acupuncture on PI3K/Akt/mTOR signaling pathway in rats with premature ovarian failure].

OBJECTIVE: To explore the effects of acupuncture and medication on PI3K/Akt/mTOR signaling pathway in rats with premature ovarian failure. METHODS: Ten of fifty SPF-grade female SD rats were randomly selected into a normal group, and the remaining 40 rats were treated with intraperitoneal injection of cyclophospha mide (30 mg/kg) for consecutive 5 days to establish rat model of premature ovarian failure. Thirty five successful rat models were randomly divided into a model group (9 cases), a medication group (9 cases), an acupuncture group A (9 cases) and an acupuncture group B (8 cases). The rats in the model group and normal group did not receive any treatment. The rats in the medication group were treated with intragastric administration of diethylstil bestrol, once a day. The rats in the acupuncture group A and acupuncture group B were respectively treated with acupuncture at different acupoints, twice a day. All the treatment was given for 4 weeks. After the treatment, enzyme-linked immunosorbent assay (ELISA) was applied to test the levels of estradiol (E2), progesterone (P), follicle stimulating hormone (FSH) and luteotropic hormone (LH). The ovarian tissue sample was processed with hematoxylin eosin (HE) staining as well as RNA and protein extraction to test the mRNA expression of estrogen receptor alpha (ERalpha), estrogen receptor beta (ERP), phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR). RESULTS: High-dose short-term in- tervention of cyclophosphamide could establish rat model of premature ovarian failure with a successful rate of 87.5%. Compared with the normal group, the vaginal smear in the model group was featured with signs of estro gen deficiency, early-follicle reduction, structural damage to the follicle, and reducing number of mature follicles; the level of E2 was significantly reduced (P<0.05), levels of P, FSH and ILH were increased (all P<0.05), and mRNA expression of estrogen-related ERP3, PI3K, Akt and mTOR were all reduced (all P<0.05). Compared with the model group, the number of mature follicle was increased in the medication group and acupuncture groups, the levels of E2 was obviously increased (all P<0.05). level of FSH was reduced (all P<0.05), and mRNA expression of PI3K, Akt and mTOR all showed an increasing trend (all P<0.05). The differences of each index result between acupuncture groups and medication group were not significant (all P>0.05). CONCLUSION: Acupuncture has certain advantage for the treatment of premature ovarian failure, which achieves similar therapeu tic effect as estrogen; the possible mechanism may be related to up-regulation of gene and protein expression in PI3K/Akt/mTOR signaling pathway.

COMT polymorphism influences decrease of ovarian follicles and emerges as a predictive factor for premature ovarian insufficiency.

BACKGROUND: Estrogens are important factors in the female reproductive functions and are processed by a number of enzymes along their metabolic pathway. The COMT gene constitutes a crucial element in estrogen metabolism and is assumed to be involved in the development of Premature Ovarian Insufficiency (POI). This study aimed to determine whether the presence of the COMT Val/Met polymorphism (rs4680) is associated to the risk of developing POI. FINDINGS: In this case-control study, we evaluated 96 infertile women with POI and 120 fertile women as controls, after obtaining a detailed history of the disease and follicle-stimulating hormone measurements, besides karyotype determination and fragile-X premutation syndrome investigation. COMT (Val/Met) genotypes were identified by real time PCR (genotyping TaqMan assay), and the results were statistically analyzed. A statistically significant difference was found in the distribution of COMT genotypes (p = 0.003) and alleles (p = 0.015) between the POI patients and the control group. CONCLUSION: We were able to demonstrate a strong association between the COMT Val/Met polymorphism and the risk of premature ovarian insufficiency in the Brazilian women evaluated. However, further studies in larger populations are necessary to confirm these findings.

TAF4b promotes mouse primordial follicle assembly and oocyte survival.

Primary ovarian insufficiency (POI) affects 1% of women under the age of 40 and is associated with premature ovarian follicle depletion. TAF4b deficiency in adult female mouse models results in hallmarks of POI including stereotyped gonadotropin alterations indicative of early menopause, poor oocyte quality, and infertility. However, the precise developmental mechanisms underlying these adult deficits remain unknown. Here we show that TAF4b is required for the initial establishment of the primordial follicle reserve at birth. Ovaries derived from TAF4b-deficient mice at birth exhibit delayed germ cell cyst breakdown and a significant increase in Activated Caspase 3 staining compared to control ovaries. Culturing neonatal TAF4b-deficient ovaries with the pan-caspase inhibitor ZVAD-FMK suppresses the excessive loss of these oocytes around the time of birth. These data reveal a novel TAF4b function in orchestrating the correct timing of germ cell cyst breakdown and establishment of the primordial follicle reserve during a critical window of development.

Epistasis between the HSD17B4 and TG polymorphisms is associated with premature ovarian failure.

OBJECTIVE: To identify whether epistasis between TG and HSD17B4 and whether polymorphisms in HSD17B4 are associated with premature ovarian failure (POF). DESIGN: Case-control genetic association study. SETTING: Research laboratory of a university. PATIENT(S): Female patients with POF (98) and controls (218) of Korean ethnicity participated in this study. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Genotype distribution, haplotype (HT) inference, and gene-gene interaction. RESULT(S): Distribution of one haplotype (A-G-A-A-G-G) on the HSD17B4 gene was significantly different between the POF group and the control group in a dominant model. In addition, the combined effect of the single nucleotide polymorphisms (SNPs) HSD17B4 rs28943592 and TG rs2076740 was significantly associated with POF (odds ratio = 7.74, 95% confidence interval = 1.67-35.94), although a significant association was not observed in the single SNP model. CONCLUSION(S): A haplotype in the HSD17B4 gene was identified that was significantly associated with resistance to POF. In addition, epistasis between two missense SNPs (rs28943592, rs2076740) located in HSD17B4 and TG was significantly associated with susceptibility to POF.

Epistasis between FSHR and CYP19A1 polymorphisms is associated with premature ovarian failure.

Follicle-stimulating hormone secreted from the pituitary gland plays a key role in human reproduction and regulates estrogen production by acting on the regulatory region of CYP19A1. We observed a significant association between premature ovarian failure and the combined genetic effect of single nucleotide polymorphism (SNP) rs4646 (CA+AA) in the 3' untranslated region of CYP19A1 and the missense FSHR SNP rs6166 (AG+GG) genotype (odds ratio 5.42, 95% confidence interval 1.96-14.98), and we identified a significant association between premature ovarian failure and the combined genetic effect of the FSHR missense SNP rs6166 (AA) and the rs4646-rs10046 haplotype (C-T)+(C-C) (odds ratio 5.47, 95% confidence interval 2.03-14.75), suggesting that two biochemical pathways may be involved in the regulation of folliculogenesis.

Poly(ADP-ribose) polymerase inhibitor, 3-aminobenzamide, protects against experimental immune ovarian failure in mice.

The activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) may play an important role in numerous pathological conditions. The aim of the present study was to clarify the role of PARP in the pathogenesis of immune ovarian failure in mice and to examine the possible protective action of PARP inhibitor, 3-aminobenzamide (3-ABA). An experimental ovarian injury induced in mice by immunization with allogenic ovarian extract impaired the meiotic maturation of oocytes and increased apoptosis and necrosis of follicular cells and cells isolated from the spleen, lymph nodes and thymus. The immunization affected blood leukogram indicating the presence of an inflammatory response. Treatment with 3-ABA (1 h before antigen administrations, 0.02 mg/g intraperitoneally, twice a week during the three-week experiment) was effective to prevent meiotic maturation impairment, cell death and inflammation. The decrease in the necrosis of follicular and immune cells after 3-ABA treatment was more pronounced than that in apoptosis. It is concluded that PARP may contribute to immune-mediated ovary injury and PARP inhibitor, 3-ABA, protects against experimental immune ovarian failure, partially via a decrease in necrotic cell death.

A novel molecular mechanism for anticancer drug-induced ovarian failure: Irinotecan HCl, an anticancer topoisomerase I inhibitor, induces specific FasL expression in granulosa cells of large ovarian follicles to enhance follicular apoptosis.

Clinical use of CPT-11 combination chemotherapy frequently induces ovarian dysfunction in premenopausal and perimenopausal cancer patients, but its mechanism remains unclear. Mouse experiments were performed to clarify the molecular mechanism of CPT-11-induced ovarian dysfunction. Clinically therapeutic doses of CPT-11 were injected intraperitoneally into 8-week-old female MCH mice, and their ovaries were examined by the TUNEL assay to detect dead cells. Immunohistochemical examinations were simultaneously performed to detect the expression of activated caspase 3, Fas antigen and Fas ligand (FasL). Furthermore, normal murine ovarian tissue fragments were incubated with recombinant soluble FasL in organ cultures and stained by the TUNEL assay to detect apoptotic cells. Intraperitoneal CPT-11 injections induced specific TUNEL-positive cells and cell death with cleaved caspase 3 expression among large ovarian follicular granulosa cells. Apoptotic follicles (follicles containing >/=10 TUNEL-positive cells per ovarian section) were only found among large follicles. The final apoptotic follicle ratios were approximately 30% of the total follicles independent of the CPT-11 dose, while CPT-11 dose-dependently enhanced apoptotic processes in murine ovarian follicles. Fas antigen was expressed in most ovarian cells, with extremely high expression levels detected in luteal cells. CPT-11 injections did not significantly increase the Fas expression levels in ovarian cells. Although no FasL expression was detected in normal ovarian tissues, CPT-11 injections significantly induced specific FasL expression in granulosa cells. Incubation of organ-cultured normal murine ovarian tissue fragments with recombinant mouse soluble FasL significantly increased the numbers of TUNEL-positive granulosa and luteal cells. In conclusion, CPT-11 dose-dependently induced specific FasL expression in granulosa cells of developing ovarian follicles. The induced FasL reacted with the Fas antigen constitutively expressed on granulosa cells, such that apoptosis can only be enhanced and induced in granulosa cells in an autocrine and/or paracrine manner. This cell lineage-specific and differentiation stage-specific apoptosis in granulosa cells is thought to be the main molecular mechanism of the ovarian dysfunction induced by CPT-11 combination chemotherapy.

Branched chain alpha-keto acid dehydrogenase, E1-beta subunit gene is associated with premature ovarian failure.

Genetic variants of the human branched chain alpha-keto acid dehydrogenase, E1-beta subunit (BCKDHB) gene were identified and they have been associated with premature ovarian failure (POF). Reconstructed haplotype from these variants was also associated with POF.

Dominant inheritance of premature ovarian failure associated with mutant mitochondrial DNA polymerase gamma.

BACKGROUND: Premature ovarian failure (POF) results in menopause before the age of 40. Recently, mutations in the catalytic subunit of mitochondrial DNA polymerase gamma (POLG) were shown to segregate with POF in families with progressive external ophthalmoplegia (PEO) and multiple large-scale rearrangements of mitochondrial DNA (mtDNA). METHODS AND RESULTS: A patient, mother and maternal grandmother are described, all presenting with POF and PEO. The mother developed parkinsonism in her sixth decade. Normal mtDNA sequence excluded mitochondrial inheritance. Sequence analysis of polymerase gamma revealed a dominant Y955C mutation that segregated with disease. Southern blot analysis demonstrated mtDNA depletion in fibroblasts (43% of controls). In contrast, multiple rearrangements of mtDNA were seen in skeletal muscle, consistent with the relative sparing of nuclear-encoded complex II activity compared with other respiratory chain enzymes. Immunoblotting of native gels showed that DNA polymerase gamma stability was not affected, whereas a reverse-transcriptase primer-extension assay suggested a trend towards reduced polymerase activity in fibroblasts. CONCLUSIONS: This study confirms that POLG mutations can segregate with POF and parkinsonism and demonstrates for the first time that the Y955C mutation can lead to mtDNA depletion. Future screening projects will determine the frequency with which POLG is involved in the aetiology of POF and its impact on reproductive counselling.

Galactose-1-phosphate uridyl transferase gene mutations in women with premature ovarian failure.

We determined the frequency of galactose-1-phosphate uridyl transferase gene mutations: Q188R, K285N, and the Duarte allelle in 86 patients with idiopathic premature ovarian failure (POF) and 95 controls. No association of the mutations with POF was found.

Physical mapping of nine Xq translocation breakpoints and identification of XPNPEP2 as a premature ovarian failure candidate gene.

Women with balanced translocations between the long arm of the X chromosome (Xq) and an autosome frequently suffer premature ovarian failure (POF). Two "critical regions" for POF which extend from Xq13-->q22 and from Xq22-->q26 have been identified using cytogenetics. To gain insight into the mechanism(s) responsible for ovarian failure in women with X;autosome translocations, we have molecularly characterized the translocation breakpoints of nine X chromosomes. We mapped the breakpoints using somatic cell hybrids retaining the derivative autosome and densely spaced markers from the X-chromosome physical map. One of the POF-associated breakpoints in a critical region (Xq25) mapped to a sequenced PAC clone. The translocation disrupts XPNPEP2, which encodes an Xaa-Pro aminopeptidase that hydrolyzes N-terminal Xaa-Pro bonds. XPNPEP2 mRNA was detected in fibroblasts that carry the translocation, suggesting that this gene at least partially escapes X inactivation. Although the physiologic substrates for the enzyme are not known, XPNPEP2 is a candidate gene for POF. Our breakpoint mapping data will help to identify additional candidate POF genes and to delineate the Xq POF critical region(s).

3beta-hydroxysteroid dehydrogenase autoantibodies are rare in premature ovarian failure.

Premature ovarian failure (POF) is a disorder of heterogeneous etiology, and autoimmunity has been suspected as one cause of POF. The steroidogenic enzyme, 3beta-hydroxysteroid dehydrogenase (3betaHSD), has been characterized as a potential autoantigen in POF as well as in insulin-dependent diabetes mellitus (type 1 diabetes). Here we studied the presence of steroid cell antibodies (SCA), autoantibodies to 3betaHSD and to two other known autoantigens in ovarian failure, steroidogenic enzymes 17alpha-hydroxylase (P450c17), and side-chain cleavage enzyme (P450scc) in POF patients and patient groups with autoimmune polyendocrinopathy syndromes type 1 and 2 (APS1 and -2), isolated Addison's disease, type 1 diabetes, and healthy controls. The SCA were found in 2 of 48 POF, 11 of 15 APS1, and 1 of 9 APS2, and autoantibodies to in vitro translated 3betaHSD protein were detected in 1 POF serum associated with Addison's disease and 3 APS1 sera. All 3betaHSD precipitating sera were also positive for SCA. However, no SCA or 3betaHSD autoantibodies were found in 38 Addison's disease, 28 type 1 diabetes, and 71 healthy control sera. In analysis of autoantibodies to P450c17 and P450scc, antibodies to these enzymes were not found in POF sera, but were found in 10 and 12 APS1 patient sera, respectively, and 1 APS2 patient serum contained anti-P450c17 antibodies. Our results show that autoantibodies to 3betaHSD in POF patients are rare and are also found in patients with APS1.

Telomerase activity in normal ovaries and premature ovarian failure.

The average age for the onset of menopause in humans is about 51 years. On the other hand, premature ovarian failure (POF) is generally defined as the onset of menopause before the age of 40 years. Telomeres have been extensively examined as a mitotic clock. Telomeric DNA is elongated by telomerase. We analyzed the telomerase activity of 20 patients with normal ovaries and 5 patients with POF. Telomerase activity was present in the normal ovaries, however it decreased with age. Eight normal ovaries under 38 years of age showed significantly higher telomerase activity among the women with a regular menstrual cycle. Two POF patients showed high telomerase activity and 3 showed low telomerase activity. Our findings indicate that telomerase is present in the normal human ovary and that telomerase activity decreases with age. Patients with follicle dysfunction showed high telomerase activity and those with follicle depletion showed very low telomerase activity. Based on these results, we speculated that the decline of telomerase activity in the ovary is related to primordial follicle depletion with age and telomerase activity can be used as a marker of the ovarian functional age.