Apoptosis and active caspase-3 expression in human granulosa cells

Dietary exposure to an environmentally relevant phthalate mixture alters follicle dynamics, hormone levels, ovarian gene expression, and pituitary gene expression in female mice

Phthalates are chemicals ubiquitously used in industry. Individual phthalates have been found to adversely affect female reproduction; however, humans are exposed to a mixture of phthalates daily, primarily through ingestion. Previous studies show that exposure to an environmentally relevant mixture of phthalates (Mix) can affect female reproduction. Little research, however, has been conducted on the effects of short-term (1 month) and long-term (6 months) exposure to Mix on ovarian functions. Thus, this study tested the hypothesis that short-term and long-term exposure to Mix alters ovarian folliculogenesis, serum hormone concentrations, pituitary gene expression, and ovarian expression of genes involved in steroidogenesis, apoptosis, cell cycle regulation, and oxidative stress. Adult CD-1 female mice were exposed to vehicle control (corn oil) or Mix (0.15-1500 ppm) in the chow for 1 or 6 months. Exposure to Mix for 1 month increased the number of atretic follicles (0.15 ppm), altered ovarian gene expression (0.15 ppm, 1500 ppm), and decreased serum testosterone (1.5 ppm) compared to control. Exposure to Mix for 6 months increased serum follicle-stimulating hormone (FSH) (0.15 ppm), decreased serum luteinizing hormone (LH) (0.15 ppm, 1.5 ppm, and 1500 ppm), decreased serum estradiol (1500 ppm), altered pituitary gene expression (1500 ppm), increased the number (1500 ppm) and percentage (1.5 ppm and 1500 ppm) of primordial follicles, and decreased the percentage of preantral (1500 ppm) and antral (1.5 ppm and 1500 ppm) follicles compared to control. These data indicate that exposure to Mix can alter folliculogenesis, steroidogenesis, and gene expression in female mice.

Classification of Atretic Small Antral Follicles in the Human Ovary

The reproductive lifespan in humans is regulated by a delicate cyclical balance between follicular recruitment and atresia in the ovary. The majority of the small antral follicles present in the ovary are progressively lost through atresia without reaching dominance, but this process remains largely underexplored. In our study, we investigated the characteristics of atretic small antral follicles and proposed a classification system based on molecular changes observed in granulosa cells, theca cells, and extracellular matrix deposition. Our findings revealed that atresia spreads in the follicle with wave-like dynamics, initiating away from the cumulus granulosa cells. We also observed an enrichment of CD68+ macrophages in the antrum during the progression of follicular atresia. This work not only provides criteria for classifying three stages of follicular atresia in small antral follicles in the human ovary but also serves as a foundation for understanding follicular degeneration and ultimately preventing or treating premature ovarian failure. Understanding follicular remodeling in the ovary could provide a means to increase the number of usable follicles and delay the depletion of the follicular reserve, increasing the reproductive lifespan.

Investigation of the Mechanisms and Experimental Verification of Yulin Formula in the Treatment of Diminished Ovarian Reserve via Network Pharmacology

Purpose

The aim of this study is to examine, using network pharmacology analysis and experimental validation, the pharmacological processes by which Yulin Formula (YLF) reduces cyclophosphamide-induced diminished ovarian reserve (DOR).

Methods

First, information about the active components, associated targets, and related genes of YLF and DOR was gathered from open-access databases. The primary targets and pathways of YLF to reduce DOR were predicted using studies of functional enrichment from the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Protein-Protein Interaction (PPI) networks. Second, we built a cyclophosphamide-induced diminished ovarian reserve (DOR) rat model to verify the primary target proteins implicated in the predicted signaling pathway to explore the mechanism of improve ovarian function of YLF.

Results

98 targets met the targets of the 82 active ingredients in YLF and DOR after searching the intersection of the active ingredient targets and DOR targets. Fourteen targets, including AKT and Caspase-3 among others, were hub targets, according to the PPI network study. The PI3K/AKT pathway was revealed to be enriched by numerous targets by the GO and KEGG enrichment studies, and it was used as a target for in vivo validation. Animal studies showed that YLF administration not only reduced the number of atretic follicles, the proportion of TUNEL-positive ovarian cells, the rate of apoptosis of granulosa cells (GCs) and the proportion of abnormal mitochondria in DOR rats, but also reversed the high expression of Caspase-3, Caspase-9, BAX, cytochrome C, PI3K and P-AKT, improving the ovarian reserve in cyclophosphamide (CTX)-induced DOR rats.

Conclusion

Our research results predicted the active ingredients and potential targets of YLF-interfering DOR by an integrated network pharmacology approach, and experimentally validated some key target proteins participated in the predicted signaling pathway. A more comprehensive understanding of the pharmacological mechanism of YLF for DOR treatment was obtained.

Follicular Atresia, Cell Proliferation, and Anti-Mullerian Hormone in Two Neotropical Primates (Aotus nancymae and Sapajus macrocephalus)

This study evaluated the follicular atresia, cell proliferation, and anti-Mullerian hormone action in Aotus nancymae and Sapajus macrocephalus during three sexual phases (follicular, luteal, and gestational). Follicular quantification and immunolocalization of Caspase-3 protein, B-cell lymphoma 2 (BCL-2), proliferating cell nuclear antigen (PCNA), and anti-Mullerian hormone (AMH) were performed. A significant difference in the quantification between preantral and antral follicles, with a progressive decrease in the antrals, was identified. Protein and hormonal markers varied significantly between follicle cell types (A. nancymae p = 0.001; S. macrocephalus, p = 0.002). Immunostaining in the preantral and antral follicles was present in all sexual phases; for Caspase-3, in granulosa cells, oocytes, and stroma; for BCL-2, in granulosa cells, oocytes, and theca; and for PCNA and AMH, in oocytes and granulosa cells. The immunostaining for Caspase-3 was more expressive in the preantral follicles (follicular phase, p < 0.05), while that for BCL-2 and PCNA was more expressive in the antral follicles of the follicular phase. The AMH was more expressive in the primary and antral follicles of nonpregnant females, in both the follicular and luteal phases. Our results contribute to understanding the ovarian follicular selection, recruitment, and degeneration of these species.

Application of Single-Cell RNA Sequencing in Ovarian Development

The ovary is a female reproductive organ that plays a key role in fertility and the maintenance of endocrine homeostasis, which is of great importance to women's health. It is characterized by a high heterogeneity, with different cellular subpopulations primarily containing oocytes, granulosa cells, stromal cells, endothelial cells, vascular smooth muscle cells, and diverse immune cell types. Each has unique and important functions. From the fetal period to old age, the ovary experiences continuous structural and functional changes, with the gene expression of each cell type undergoing dramatic changes. In addition, ovarian development strongly relies on the communication between germ and somatic cells. Compared to traditional bulk RNA sequencing techniques, the single-cell RNA sequencing (scRNA-seq) approach has substantial advantages in analyzing individual cells within an ever-changing and complicated tissue, classifying them into cell types, characterizing single cells, delineating the cellular developmental trajectory, and studying cell-to-cell interactions. In this review, we present single-cell transcriptome mapping of the ovary, summarize the characteristics of the important constituent cells of the ovary and the critical cellular developmental processes, and describe key signaling pathways for cell-to-cell communication in the ovary, as revealed by scRNA-seq. This review will undoubtedly improve our understanding of the characteristics of ovarian cells and development, thus enabling the identification of novel therapeutic targets for ovarian-related diseases.

Decreased fatty acids induced granulosa cell apoptosis in patients with diminished ovarian reserve

PURPOSE

To investigate whether fatty acid changes in granulosa cells (GCs) underly the pathogenic mechanisms of diminished ovarian reserve (DOR).

METHODS

GCs were obtained from patients with DOR (n = 70) and normal ovarian reserve (NOR, n = 70). Analysis of fatty acids changes in GCs was then analyzed.

RESULTS

Patients with DOR had significantly lower levels of antral follicle count and anti-Mullerian hormone and higher levels of follicle-stimulating hormone compared with NOR patients (P < 0.001). The good-quality embryo rate was notably decreased in DOR patients (51.99 vs 39.52%, P < 0.05). A total of 15 significantly decreased fatty acids in GCs from patients with DOR. The ATP levels were markedly lower in DOR patients than in NOR patients (39.07 ± 12.89 vs 23.21 ± 13.69%, P < 0.05). Mitochondrial membrane potential decreased in DOR patients (P < 0.01). In GCs from DOR patients, the β-oxidation genes (HADHA and ACSL) and DNA repair genes (PRKDC and RAD50) were significantly downregulated (P < 0.05). The γH2AX foci/nucleus ratio in DOR patients markedly increased relative to that of NOR patients (0.31 ± 0.03 vs 0.87 ± 0.07, P < 0.001). Meanwhile, the apoptosis rate of GCs was significantly higher in DOR patients (6.43 ± 2.11 vs 48.06 ± 6.72%, P < 0.01).

CONCLUSION

GC apoptosis resulting from the decrease of fatty acids, and associated with reduced ATP production and DNA damage, may contribute to the pathogenic mechanisms responsible for DOR.

Perfluorooctanoic acid promotes proliferation of the human granulosa cell line HGrC1 and alters expression of cell cycle genes and Hippo pathway effector YAP1

Perfluorooctanoic acid (PFOA) is a common environmental contaminant that belongs to a group of manmade fluorinated chemicals called per- and polyfluoroalkyl substances (PFAS). Due to the pervasive nature of PFOA, the environmental health risks of PFOA contamination and exposure on reproductive health have increasing concern. In the present study, we exposed HGrC1 cells, an immortalized human granulosa cell line, to environmentally relevant (1-10 μM) concentrations of PFOA. Results indicated that HGrC1 cells treated with PFOA had increased proliferation and migration relative to vehicle treated controls. No differences in cell apoptosis were observed with 1-10 μM PFOA. Gene expression analysis revealed increases in mRNA transcripts for cell cycle regulators CCND1, CCNA2, and CCNB1. Upregulation of YAP1 protein and downstream target CTGF protein was also observed, suggesting that the Hippo pathway is involved in the proliferation and migratory effects of PFOA on HGrC1 cells. Further, the YAP1 inhibitor Verteporfin prevented the stimulatory effects of PFOA on HGrC1 cells. Together, these findings support a role for the Hippo pathway effector YAP1 in response to PFOA exposure in human granulosa cells.

Expression of pro-apoptotic and anti-apoptotic proteins in granulosa cells of women with diminished ovarian reserve

PURPOSE

To evaluate the expressions of caspase-3 and cytochrome c and heat shock protein 70 (Hsp70) in granulosa cells (GCs) from women with normal ovarian reserve (NOR) and diminished ovarian reserve (DOR) undergoing intracytoplasmic sperm injection (ICSI).

METHODS

GCs were collected from 117 infertile women during oocyte retrieval. Patients were classified into four groups as follows: DOR-COC score of 0, DOR-COC score of I, NOR-COC score of 0, and NOR-COC score of I. The caspase-3, cytochrome c, and Hsp70 analyses were performed immunohistochemically in GCs. The ICSI outcomes were evaluated prospectively.

RESULTS

The clinical pregnancy and live birth rates were higher in DOR-COC score of I (15, 30.6%; 14, 38.9%) and NOR-COC score of I (19, 38.77%; 19, 52.7%) groups, compared with DOR-COC score of 0 (12, 24.4%; 3, 6.1%) and NOR-COC score of 0 (3, 6.1%; 0%) groups (p = 0.0001; 0.00002), respectively. Caspase-3 and cytochrome c expression levels were higher in DOR-COC score of 0 (23, 65.7%; 25, 71.4%) and NOR-COC score of 0 groups (19, 61.3%; 20, 64.5%), compared with DOR-COC score of I (8, 32%; 9, 36%) and NOR-COC score of I groups (7, 26.9%; 8, 30.8%) (p = 0.00297; p = 0.002), respectively. Lower expression levels of Hsp70 were found in DOR-COC score of 0 (11, 31.4%) and NOR-COC score of 0 groups (10, 32.3%), compared with DOR-COC score of I (16, 64%) and NOR-COC score of I groups (20, 76.9%) (p = 0.001), respectively. Hsp70 expression levels were positively correlated with the number of day 3 good-quality embryo and negatively correlated with estradiol levels in the DOR group.

CONCLUSION

Our data suggest that COC score of 0 is associated with increased expression levels of apoptotic proteins, decreased expression levels of anti-apoptotic protein, and poor ICSI clinical outcomes in women with and without DOR.

An online tool for predicting ovarian reserve based on AMH level and age: A retrospective cohort study

PURPOSE

To establish a more convenient ovarian reserve model with anti-Müllerian hormone (AMH) level and age (the AA model), with blood samples taken at any time in the menstrual cycle.

METHODS

We have established this AA model for predicting ovarian reserve using the AMH level and age. The outcome variable was defined as poor ovarian response (POR) with <5 oocytes retrieved during assisted reproductive technology treatment cycles. Least Absolute Shrinkage and Selection Operator logistic regression with 5-fold cross validation methods was applied to construct the model, and that with the lowest scaled log-likelihood was selected as the final one.

RESULTS

The areas under the receiver operating characteristic curve for the training, inner, and external validation sets were 0.862, 0.843, and 0.854 respectively. The main effects of AMH level and age contributing to the prediction of POR were 95.3% and 1.8%, respectively. The incidences of POR increased with its predicted probability in both the model building and in external validation datasets, indicating its stability. An online website-based tool for assessing the score of ovarian reserve (http://121.43.113.123:9999) has been developed.

CONCLUSIONS

Based on external validation data, the AA model performed well in predicting POR, and was more cost-effective and convenient than our previous published models.

Hemodynamic, endocrine, and gene expression mechanisms regulating equine ovarian follicular and cellular development

Ovulatory follicle development and associated oocyte maturation involve complex coordinated molecular and cellular mechanisms not yet fully understood. This study addresses the relationships among follicle diameter, follicle wall blood flow, follicular-fluid factors, and gene expression for follicle growth, steroidogenesis, angiogenesis, and apoptosis in granulosa/cumulus cells and oocytes during different stages from the beginning of largest/ovulatory follicle to impending ovulation in mares. The most remarkable findings were (i) a positive association between follicle development, follicle blood flow, intrafollicular follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, and messenger RNA (mRNA) expression for FSHR and LHCGR in granulosa cells of the largest/ovulatory follicle; (ii) a plateau or decrease in follicle diameter and blood flow and granulosa cell mRNA for FSHR, LHCGR, IGF1R, VEGFR2, CYP19A1, and CASP3 at the preovulatory stage; (iii) higher StAR and BCL2 and lower CASP3 mRNA in granulosa cells at the time of impending ovulation; (iv) greater IGF1R mRNA for granulosa cells at the predeviation stage; and (v) lower FSHR, LHCGR, IGF1R, and VEGFR2 mRNA in cumulus cells and greater LHCGR and IGF1R mRNA in oocytes at the ovulatory stage. This study is a critical advance in the understanding of molecular mechanisms of follicle development and oocyte maturation and is expected to be vital for future studies targeting potential markers.

Protegrin-1 inhibits porcine ovarian granulosa cell apoptosis from H2O2-induced oxidative stress via the PERK/eIF2α/CHOP signaling pathway in vitro

In mammals, oxidative stress-induced apoptosis of granulosa cells is one of the major causes of follicular atresia, affecting ovarian physiological function. Protegrin-1 (PG-1) is an antimicrobial peptide with effective antimicrobial activity, immunomodulatory function, and porcine growth-promoting effects. PG-1 has been detected in porcine ovaries follicles. This study aimed to investigate the effect of PG-1 on oxidative stress-induced apoptosis of porcine ovarian granulosa cells and the underlying molecular mechanism. Granulosa cells were obtained from porcine follicles and treated with H₂O₂ to establish the oxidative stress model, and then treated with or without PG-1 (10 μg/mL). PG-1 significantly suppressed H₂O₂-induced apoptosis in granulosa cells after 24 h of treatment. Furthermore, these results revealed that PG-1 increased the mRNA and protein expression of anti-apoptotic B cell lymphoma/leukemia 2 (BCL2) and the BCL2/Bcl-2-associated X protein (BAX) ratio while decreasing the expression of pro-apoptotic BAX and active caspase-3. Using Western blot analysis, it was found that PG-1 decreased the phosphorylation of RNA-like endoplasmic reticulum kinase (PERK) and the α-subunit of eukaryotic initiation factor 2 (eIF2α) as well as the protein expression level of CCAAT enhancer-binding protein homologous protein (CHOP), all of which were increased by H₂O₂. Moreover, inhibitors against PERK and phospho-eIF2ɑ both suppressed the H₂O₂-induced granulosa cells apoptosis and enhanced the anti-apoptosis effect of PG-1. Taken together, our findings demonstrated that PG-1 inhibited porcine ovarian granulosa cell apoptosis from oxidative stress via the PERK/eIF2α/CHOP signaling pathway in vitro, which suggests the novel regulatory function of the antimicrobial peptide in the ovary.

Syzygium jambos extract mitigates pancreatic oxidative stress, inflammation and apoptosis and modulates hepatic IRS-2/AKT/GLUT4 signaling pathway in streptozotocin-induced diabetic rats

The protective effect of Syzygium jambos (SJ) bark extract against streptozotocin-induced diabetes was tested in rats. Animals were treated with 100 or 200 mg/kg of the extract or glibenclamide, 0.5 mg/kg per os, once daily: started 2 days before streptozotocin (STZ) injection and lasted for 14 days after STZ injection. The effect of the extract was also evaluated on normal rats in comparison with glibenclamide. Diabetic animals showed an elevated blood glucose level, positive glycosuria, elevated fructosamine, pancreatic malondialdehyde, pancreatic TNF-a, and pancreatic caspase-3 levels and decreased serum insulin, pancreatic IL-10, pancreatic BCL-2, reduced glutathione (GSH), liver insulin substrate-2, liver phosphorylated protein kinase B (p-AKT) and liver glucose transporter 4 (GLUT4) levels. Histopathological examination of diabetic rats revealed islets destruction and vacuolation and collagen fibers deposition. All these changes were mitigated dose dependently by the extract. The high dose of the extract exerted comparable effects with glibenclamide in most studied parameters. These results indicated the protective role of SJ against the STZ diabetogenic action. In the pancreatic and hepatic tissue of diabetic rats, SJ effectively recovered pancreatic cells by reducing hyperglycemia through activating endogenous antioxidants, dynamic insulin production, and suppressing inflammation and apoptosis. The observed results might be attributed to the existence of 10 secondary metabolites as annotated by LC-MS. Taken together, S. jambos is a potential candidate for further studies to confirm its activities as a therapeutic agent for diabetic patients.

Clinical Applications of Serum Anti-Müllerian Hormone Measurements in Both Males and Females: An Update

Infertility is one of the most common non-communicable diseases, affecting both men and women equally. Ovarian reserve, the number of primordial follicles in the ovaries is believed to be the most important determinants for female fertility. Anti-Müllerian hormone (AMH) secreted from granulosa cells of growing follicles is recognized as the most important biomarker for ovarian reserve. Ovarian reserve models have been developed using AMH and other hormonal indicators, thus childbearing plans and reproductive choices could be arranged by women. In assisted reproductive technology cycles, measurement of AMH helps to predict ovarian response and guide recombinant follicle-stimulating hormone dosing in women. Serum AMH level is increasingly being recognized as a potential surrogate marker for polycystic ovarian morphology, one of the criteria for diagnosis of polycystic ovarian syndrome. AMH is also secreted by Sertoli cells of testes in men, and AMH measurements in the prediction of surgical sperm recovery rate in men have also been investigated. AMH levels are significantly higher in boys than in girls before puberty. Therefore, serum levels of AMH in combination with testosterone is used for the differential diagnosis of disorders of sex development, anorchia, non-obstructive azoospermia, and persistent Müllerian duct syndrome. Recently, serum AMH measurements have also been used in fertility preservation programs in oncofertility, screening for granulosa cell tumors, and prediction of menopause applications. In this review, we will focus on clinical application of AMH in fertility assessments for healthy men and women, as well as for cancer patients.

•

Anti-Müllerian hormone (AMH) plays a key role in models assessing ovarian reserve

•

AMH is used for the differential diagnosis of disorders of sex development

•

AMH provides a molecular marker for related fertility and infertility disorders

•

An international standard will aid in the development of various AMH assays

Pro-caspase-3 is constitutively expressed in luteinized granulosa cells from women undergoing controlled ovarian stimulation for in vitro fertilization

Apoptosis regulation in luteinized granulosa cells (LGC) during assisted reproduction procedures is still controversial. Caspase-3 is a major apoptosis mediator encoded by CASP3 and formed through cleavage of its precursor pro-caspase-3. The aim of this study was to investigate the expression patterns of pro-caspase-3 (mRNA and protein) and cleaved caspase-3 in human LGC. Thirty-five women undergoing controlled ovarian stimulation for in vitro fertilization were prospectively enrolled in the study. LGC were isolated from follicular fluid during oocyte pickup and evaluated by immunocytochemistry for pro-caspase-3 and cleaved caspase-3, and by real-time PCR for CASP3 mRNA expression. We found a positive staining of pro-caspase-3 in 77 % of the LGC (95 % confidence interval [CI] 60%-84%), whereas cleaved caspase-3 was found in only 4% of the cells (95 % CI 3%-6%). The abundance of cells expressing pro-caspase-3 was independent from CASP3 mRNA levels (r = 0.24, p = 0.255) and did not correlate with the amount of cleaved caspase-3 (r = -0.24, p = 0.186). Multivariable logistic regression showed that pro-caspase-3 positivity was not influenced by clinical characteristics such as age, cause or length of infertility, antral follicle count or hormonal drugs used to induce ovulation. These findings suggest that pro-caspase-3 is constitutively expressed in LGC, allowing quick cleavage into active caspase-3 and apoptosis triggering whenever needed in the course of gonadotropin-induced follicular development.

Adverse effect of superoxide-induced mitochondrial damage in granulosa cells on follicular development in mouse ovaries

High mitochondrial oxidative phosphorylation (mt-OXPHOS) levels are required to supply the ATP necessary for follicle-stimulating hormone (FSH)-induced granulosa cell proliferation during the follicular development process. Consequently, excessive reactive oxygen species (ROS) might be generated and have an adverse effect on follicular health. This study aimed to elucidate the negative effects of ROS on mitochondrial functions in FSH-stimulated granulosa cells during the follicular development process and to investigate whether pyrroloquinoline quinone (PQQ) treatment could accelerate this process by ameliorating the adverse effects. To do this, both in vitro and in vivo experiments were performed with granulosa cells from superovulated immature (3-week-old) mice that were pretreated with or without PQQ, and a natural mating study was also performed. The ROS level in FSH-/eCG-stimulated granulosa cells was significantly increased. Moreover, high oxidative stress and mtDNA damage levels were evident in the granulosa cells. PQQ treatment not only reduced the ROS and oxidative stress levels but also ameliorated mtDNA damage, accelerated FSH-/eCG-induced ATP production, and increased the mitochondrial membrane potential and the expression levels of mitochondrial genes (Nd1, Cytb, Cox1, ATPase6) and the mt-ND1 protein. Accordingly, the proliferation and viability of granulosa cells, numbers of healthy preovulatory follicles and ovulated oocytes and serum estrogen level were significantly improved, while the apoptosis of granulosa cells was reduced. However, PQQ treatment did not change the fertility parameters in mature mice with natural cycles but did significantly increased the number of offspring born per delivery. These results revealed that ROS-associated damage in FSH-stimulated granulosa cells adversely affects their physiology and follicular health during the follicular development process. Treatment with PQQ is a beneficial tool to increase both the number of ovulated oocytes and pups per delivery.

Boron Attenuates Heat Stress-Induced Apoptosis by Inhibiting Endoplasmic Reticulum Stress in Mouse Granulosa Cells

Heat stress-induced apoptosis in granulosa cells is mediated by multiple apoptotic signaling pathways, including endoplasmic reticulum (ER) stress. Boron is a naturally occurring trace element with several cytoprotective properties. Nonetheless, the molecular mechanisms involved in the protective functions of boron in granulosa cells undergoing apoptosis caused by heat stress (HS) remain unclear. In this study, we investigated the role of boric acid, a predominant chemical form of boron, in HS-induced apoptotic damage in mouse granulosa cells (mGCs) and explored the underlying mechanisms. We found that HS treatment suppressed cell viability; increased the apoptotic rate of cells; potentiated the activity of caspase-3, a key player in the caspase-mediated apoptotic signaling pathway; and activated ER stress markers, including glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) in mGCs. However, boric acid treatment effectively alleviated the effects of both HS-induced and thapsigargin (an ER stress agonist)-induced apoptosis, such as the enhanced activity of caspase-3 and increase in GRP78 and CHOP expression. Moreover, treatment with 4-phenylbutyrate (4-PBA), an ER stress antagonist, significantly attenuated these HS-induced adverse effects in mGCs. In addition, boric acid supplementation in the culture medium significantly restored the decreased estradiol levels in heat-treated mGCs. The administration of boric acid to female mice previously exposed to hyperthermal conditions effectively restored the levels of serum estradiol in vivo. Collectively, these findings suggest that HS induces apoptosis in mGCs via ER stress pathways and that boron has a protective effect against these adverse effects. This study provides novel insights into the benefits of using boron against heat-induced apoptosis.

Role of GnRH and GnIH in paracrine/autocrine control of final oocyte maturation

The control of oocyte growth and its final maturation is multifactorial and involves a number of hypothalamic, hypophyseal, and peripheral hormones. In this study, we investigated the direct actions of the gonadotropin-releasing hormone (GnRH) and the gonadotropin-inhibitory hormone (GnIH), which are expressed in the ovarian follicles, on final oocyte maturation in zebrafish, in vitro. Our study demonstrates the expression of GnRH and GnIH in the ovarian follicles of zebrafish (Danio rerio) at different stages of development and provides information on the direct action of these hormones on final oocyte maturation. Treatment with both GnRH and GnIH peptides stimulated the germinal vesicle breakdown (GVBD) of the late-vitellogenic oocyte. Both the GnRH and GnIH treatments showed no significant change in the caspase-3 activity of pre-vitellogenic and mid-vitellogenic oocytes, while they displayed different responses in the late-vitellogenic follicles. The GnRH treatment increased caspase-3 activity, whereas the GnIH reduced caspase-3 activity in the late-vitellogenic follicles. We also investigated the effects of GnRH and GnIH on the hCG-induced resumption of meiosis and caspase activity in vitro. GnRH and GnIH were found to have a similar effect on the hCG-induced resumption of meiosis, while they showed the opposite effect on caspase-3 activity. Furthermore, we investigated the effects of concomitant treatment of GnRH and GnIH peptides with hCG. The results demonstrated that the presence of both GnRH3 and GnIH are necessary for the normal induction of final oocyte maturation by gonadotropins. The findings support the hypothesis that GnIH and GnRH peptides produced in the ovary are part of a complex multifactorial regulatory system that controls zebrafish final oocyte maturation in paracrine/autocrine manner working in concert with gonadotropin hormones.

MALDI-TOF Mass Spectrometry Revealed Significant Lipid Variations in Follicular Fluid and Somatic Follicular Cells but Not in Enclosed Oocytes between the Large Dominant and Small Subordinate Follicles in Bovine Ovary

Lipid metabolism in ovarian follicular cells supports the preparation of an enclosed oocyte to ovulation. We aimed to compare lipid composition of a dominant large follicle (LF) and subordinated small follicles (SFs) within the same ovaries. Mass spectrometry imaging displayed the differences in the distribution of several lipid features between the different follicles. Comparison of lipid fingerprints between LF and SF by Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight (MALDI-TOF) mass spectrometry revealed that in the oocytes, only 8 out of 468 detected lipids (1.7%) significantly changed their abundance (p < 0.05, fold change > 2). In contrast, follicular fluid (FF), granulosa, theca and cumulus cells demonstrated 55.5%, 14.9%, 5.3% and 9.8% of significantly varied features between LF and SF, respectively. In total, 25.2% of differential lipids were identified and indicated potential changes in membrane and signaling lipids. Tremendous changes in FF lipid composition were likely due to the stage specific secretions from somatic follicular cells that was in line with the differences observed from FF extracellular vesicles and gene expression of candidate genes in granulosa and theca cells between LF and SF. In addition, lipid storage in granulosa and theca cells varied in relation to follicular size and atresia. Differences in follicular cells lipid profiles between LF and SF may probably reflect follicle atresia degree and/or accumulation of appropriate lipids for post-ovulation processes as formation of corpus luteum. In contrast, the enclosed oocyte seems to be protected during final follicular growth, likely due in part to significant lipid transformations in surrounding cumulus cells. Therefore, the enclosed oocyte could likely keep lipid building blocks and energy resources to support further maturation and early embryo development.

Oxidative Stress and Endoplasmic Reticulum Stress Are Involved in the Protective Effect of Alpha Lipoic Acid Against Heat Damage in Chicken Testes

Simple Summary

In male animals, heat stress causes injury to the testes, resulting in an increase in the number of deformed sperm, a reduction in testosterone production, and consequently, reduced reproductive performance. As an important antioxidant, alpha lipoic acid (ALA) has been reported to have a protective effect against testicular injury caused by various pathological factors. However, few studies have focused on the role of ALA in heat-induced testicular lesions. In this study, the effects of ALA on histopathological parameters, the activity of key antioxidant enzymes involved in oxidative stress, biomarkers of endoplasmic reticulum stress signaling in the testicular tissue, and testosterone levels in serum were evaluated in heat-stressed chickens. The results showed that ALA significantly alleviated heat stress-induced adverse effects by affecting the activities of antioxidant enzymes, the expression of endoplasmic reticulum stress-related apoptotic modulators, and the protein levels of steroidogenic genes in the testes of chickens exposed to heat stress. These results suggest that in chickens, ALA may be beneficial for ameliorating decreased reproductive performance caused by heat stress and this study provides the basis for the design of novel therapies for heat-induced testicular damage.

Abstract

Heat stress (HS) causes testicular injury, resulting in decreased fertility. Alpha-lipoic acid (ALA) is a well-known antioxidant. The aim of this study was to investigate the protective effects of ALA on HS-induced testicular damage in chickens. Histological changes; biomarkers of oxidative stress, including glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA); markers of endoplasmic reticulum (ER) stress, including glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP); apoptosis-related modulators, including Bax, Bcl-2, and caspase 3, in testicular tissue and serum testosterone levels were evaluated in chickens under heat stress. Heat stress induces spermatogenic cell abnormalities in chicken testes. Compared to the HS group, the histomorphological abnormalities in testicular tissue were visibly ameliorated, with significant increases in the enzyme activities of GPx, SOD, and CAT, increased serum testosterone concentration, and decreased MDA levels in the ALA + HS group. Consistent with these results, compared with the HS group, the protein levels of GRP78, CHOP, caspase 3, and Bax were significantly decreased, whereas Bcl-2, StAR, and 3β-HSD protein levels were increased in the ALA + HS group. Collectively, these findings suggest that ALA significantly ameliorates the heat-induced histomorphological abnormalities in the testes and decreased testosterone production by potentiating the activities of anti-oxidative enzymes (GPx, SOD, and CAT), inhibiting ER stress-related apoptotic pathways (Bax, Bcl-2, and caspase 3), and increasing steroidogenic gene (StAR and 3β-HSD) expression in chickens.

Selenium Attenuates Chronic Heat Stress-Induced Apoptosis via the Inhibition of Endoplasmic Reticulum Stress in Mouse Granulosa Cells

Heat stress induces apoptosis in various cells. Selenium, an essential micronutrient, has beneficial effects in maintaining the cellular physiological functions. However, its potential protective action against chronic heat stress (CHS)-induced apoptosis in granulosa cells and the related molecular mechanisms are not fully elucidated. In this study, we investigated the roles of selenium in CHS-induced apoptosis in mouse granulosa cells and explored its underlying mechanism. The heat treatment for 6–48 h induced apoptosis, potentiated caspase 3 activity, increased the expression levels of apoptosis-related gene BAX and ER stress markers, glucose-regulated protein 78 (GRP78), and CCAAT/enhancer binding protein homologous protein (CHOP) in mouse granulosa cells. The treatment with ER stress inhibitor 4-PBA significantly attenuated the adverse effects caused by CHS. Selenium treatment significantly attenuated the CHS- or thapsigargin (Tg, an ER stress activator)-induced apoptosis, potentiation of caspase 3 activity, and the increased protein expression levels of BAX, GRP78, and CHOP. Additionally, treatment of the cells with 5 ng/mL selenium significantly ameliorated the levels of estradiol, which were decreased in response to heat exposure. Consistently, administering selenium supplement alleviated the hyperthermia-caused reduction in the serum estradiol levels in vivo. Together, our findings indicate that selenium has protective effects on CHS-induced apoptosis via inhibition of the ER stress pathway. The current study provides new insights in understanding the role of selenium during the process of heat-induced cell apoptosis.

Primary immunoprevention of adult onset cancers by vaccinating against retired tissue-specific self-proteins

Despite the enormous success of childhood prophylactic vaccination against diseases caused by pathogens, there is currently no similar preventive vaccine program against diseases confronted with age like breast cancer and ovarian cancer. With the exception of the annual influenza vaccine, current recommendations for adult vaccination are for either primary vaccines not received during childhood or for booster vaccinations to maintain the immunity against pathogens already induced during childhood. Here we describe a strategy to provide prophylactic pre-emptive immunity against the development of adult onset cancers not associated with any definitive etiopathogenic agent. We propose that safe and effective pre-emptive immunity may be induced in cancer-free subjects by vaccination against immunodominant tissue-specific self-proteins that are 'retired' from expression in normal tissues as part of the normal aging process but are expressed in tumors that emerge with age. Primary immunoprevention of adult onset cancers like breast cancer and ovarian cancer represents a great challenge and an even greater unmet need for our current healthcare.

Knockdown of CREB1 promotes apoptosis and decreases estradiol synthesis in mouse granulosa cells

Cyclic AMP response element-binding protein 1 (CREB1), a member of the CREB family, is known to be involved in follicular growth, ovulation, and ovarian disease. However, the physiological function of CREB1 in mouse granulosa cells (mGCs) remains lagerly unknown. The aim of this study was to determine the role of CREB1 in mGCs by knocking down CREB1 expression. CREB1 knock-down in mGCs at the mRNA and protein levels, was confirmed by quantitative real-time polymerase chain reaction and western blot. Results of enzyme linked immunosorbent assay revealed that CREB1 knockdown significantly decreased the concentrations of estradiol (E2) and progesterone (P4) in mGCs. Furthermore, the CREB1 knockdown in mGCs promoted cell proliferation and apoptosis, and arrested the cell cycle in S-phase. To elucidate the regulatory mechanism underlying the effects of CREB1 knockdown on steroid synthesis, cell cycle, and apoptosis, we measured the protein expression levels of several related genes in mGCs knocked down CREB1. When CREB1 was knocked down, the expression of Cyp1b1 and Cyp19a1, which encode steroidogenic enzymes, was down-regulated; the expression of the cell cycle factors CyclinA1, CyclinB1, and CyclinD2 were significantly decreased. Among apoptosis-related genes, Bcl-2 was down-regulated, whereas Bax and cleaved Caspase3 were upregulated. Moreover, CREB1 knockdown significantly decreased expression level of Has2, Ptgs2, and Igfbp4, which are essential genes for folliculogenesis in mGCs. Taken together, these findings suggested that CREB1 might be a key regulator of mGCs through regulating steroid synthesis, cell proliferation, cell cycle, apoptosis, and other regulators of folliculogenesis.

Research progress on the role of melatonin and its receptors in animal reproduction: A comprehensive review

Melatonin and its receptors play a crucial role in the regulation of the animal reproductive process, primarily in follicular development. However, the role that melatonin performs in regulating hormones related with reproduction remains unclear. Melatonin and its receptors are present both in female and male animals' organs, such as ovaries, heart, brain and liver. Melatonin regulates ovarian actions and is a key mediator of reproductive actions. Melatonin has numerous effects on animal reproduction, such as protection of gametes and embryos, response to clock genes, immune-neuroendocrine, reconciliation of seasonal variations in immune function, and silence or blockage of genes. The growth ratio of reproductive illnesses in animals has raised a remarkable concern for the government, animal caretakers and farm managers. In order to resolve this challenging issue, it is very necessary to conduct state-of-the-art research on melatonin and its receptors because melatonin has considerable physiognomies. This review article presents a current contemporary research conducted by numerous researchers from the entire world on the role of melatonin and its receptors in animal reproduction, from the year 1985 to the year 2017. Furthermore, this review shows scientific research challenges related to melatonin receptors and their explanations based on the findings of 172 numerous research articles, and also represents significant proficiencies of melatonin in order to show enthusiastic study direction for animal reproduction researchers.

Granulosa Cell Apoptosis in the Ovarian Follicle-A Changing View

Recent studies challenge the previous view that apoptosis within the granulosa cells of the maturing ovarian follicle is a reflection of aging and consequently a marker for poor quality of the contained oocyte. On the contrary, apoptosis within the granulosa cells is an integral part of normal development and has limited predictive capability regarding oocyte quality or the ensuing pregnancy rate in in vitro fertilization programs. This review article covers our revised understanding of the process of apoptosis within the ovarian follicle, its three phenotypes, the major signaling pathways underlying apoptosis as well as the associated mitochondrial pathways.

Knockdown of melatonin receptor 1 and induction of follicle-stimulating hormone on the regulation of mouse granulosa cell function

Melatonin receptor 1 (MT1) performs a critical role in the regulation of the animal reproductive system, particularly in follicular growth, and has a considerable effect on reproductive performance. However, the role that MT1 plays in regulating hormones associated with reproduction remains unclear. This study was designed to examine the physiological role of constitutive MT1 silencing and follicle stimulating hormone (FSH) treatment in reproduction, making use of mouse granulosa cells (mGCs) as a model. To understand the constitutive role of MT1 in ovarian physiology, the RNAi-Ready pSIREN-RETROQ-ZsGreen Vector mediated recombinant pshRNA was used to silence MT1 gene expression. Furthermore, we observed that the expression of MT1 was successfully inhibited both at the protein and mRNA levels (P<0.001). We demonstrated that RNAi-B-mediated MT1 down-regulation significantly promoted apoptosis (P<0.001), inhibited proliferation, and regulated the cell cycle at the S-phase; conversely, FSH treatment partially aided the apoptotic effect and improved proliferation but showed a significant effect at the S-phase of the cell cycle. Transitory knockdown of MT1 proved essential in the function of mGCs, as it significantly decreased cyclic adenosine monophospahte (cAMP) level and increased cell apoptosis. Following knockdown of MT1, the expression of Bax was significantly up-regulated (P<0.001), but Bcl-2 was slightly down-regulated, both at the transcriptional and at translational levels. Moreover, the silencing of MT1 and its constitutive effect on FSH significantly promoted an increase in estradiol (P<0.001) and slightly decreased the concentration of progesterone. Together, our data indicates that MT1 suppression leads to interference in the normal physiological function of the ovary by enhancing follicular apoptosis, inhibiting proliferation, and influencing hormonal signaling, whereas constitutive FSH treatment counteracted the negative down-regulatory effects of MT1 on mGCs.

Effects of phyto-oestrogen quercetin on productive performance, hormones, reproductive organs and apoptotic genes in laying hens

Quercetin, a polyphenolic flavonoid with diverse biological activities including anti-inflammatory and antiviral, inhibits lipid peroxidation, prevents oxidative injury and cell death. The purpose of the research was to investigate the effect of quercetin on productive performance, reproductive organs, hormones and apoptotic genes in laying hens between 37 and 45 weeks of age, because of the structure and oestrogenic activities similar to 17β-oestradiol. The trial was conducted using 240 Hessian laying hens (37 weeks old), housed in wire cages with two hens in each cage. These hens were randomly allotted to four treatments with six replicates, 10 hens in each replicate and fed with diets containing quercetin as 0, 0.2, 0.4 and 0.6 g/kg feed for 8 weeks. The results showed that dietary quercetin significantly increased (p < .05) the laying rate and was higher in group supplemented with 0.4 g/kg, and feed-egg ratio was decreased (p < .05) by quercetin. Dietary quercetin has no effect (p > .05) on average egg weight and average daily feed intake. Compared with control, secretion of hormones, oestradiol (E₂ )_, progesterone (P4), follicle-stimulating hormone (FSH), luteinizing hormone (LH), insulin-like growth factors-1 (IGF-1) and growth hormone (GH), was found to be significantly higher (p < .05) in quercetin-supplemented groups. Also ovary index, uterus index and oviduct index were not significantly influenced (p > .05) by quercetin, whereas magnum index, isthmus index, magnum length, isthmus length and follicle numbers were significantly increased (p < .05) with quercetin supplementation. Additionally, expression of apoptotic genes was significantly (p < .05) up-regulated or down-regulated by quercetin. These results indicated that quercetin improved productive performance, and its mechanism may be due to the oestrogen-like activities of quercetin.

Fresh embryos versus freeze-all embryos - transfer strategies: Nuances of a meta-analysis

Objective

The present meta-analysis aimed to evaluate whether the freeze-all strategy (Freeze/All-ET) could bring about improvements in the clinical assisted reproductive technique (ART) outcomes when compared with the fresh embryo transfer strategy (Fresh-ET) in patients undergoing an ART cycle in accordance with the mean number of oocytes collected.

Methods

A systematic review based on electronic searches in databases (PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane Central Register of Controlled Trials) was carried out to identify randomized controlled trails (RCTs) comparing ART outcomes between fresh-embryo transfers versus elective frozen-embryo transfers up to February of 2017. Four reviewers independently evaluated abstracts, validity assessment and data extraction. Odds Ratio (OR) values with a 95% confidence interval (CI), and heterogeneity were evaluated.

Results

Five RCTs were included as targets for data extraction and meta-analysis purposes. The results of this meta-analysis were divided into two parts (Freeze/All-ET versus Fresh-ET): Part I- All trials in which the mean number of collected oocytes was >12 and <21 for ongoing pregnancy rate (OR=1.24; 95%CI=1.06-1.44), clinical pregnancy rate (OR=1.19; 95%CI=0.98-1.43), live birth rate (OR= 1.39; 95%CI=0.99-1.95), and miscarriage rate (OR=0.68; 95%CI=0.46-1.00); Part II- Three studies where the mean number of oocytes retrieved was >12 and <15 for ongoing pregnancy rate (OR=1.17; 95%CI=1.00-1.38), clinical pregnancy rate (OR=1.34; 95%CI=0.79-2.28), live birth rate (OR= 1.24; 95%CI=1.00-1.55), and miscarriage rate (RR=0.68; 95%CI=0.46-1.02).

Conclusions

The freeze-all strategy could be favorable when high numbers of oocytes are collected, signaling an association between higher ovarian stimulation and consequent impairment of endometrial receptivity. However, when the mean number of oocytes collected is <15, the freeze-all strategy does not appear to be advantageous.

Apoptosis of bovine granulosa cells: Intracellular pathways and differentiation

Follicular atresia in granulosa and theca cells occurs by apoptosis through weak hormonal stimulation. We have previously proposed an in vitro model to study this process by inducing apoptosis in BGC-1, a bovine granulosa cell line, and in primary cultures from ovaries with or without corpus luteum (CPGB+ and CPGB-, respectively), with different doses of gonadotropin releasing hormone (GnRH) analogs (leuprolide acetate (LA) as agonist and antide as antagonist). BGC-1 represent immature granulosa cells, whereas CPGB represent different degrees of luteinization. Our aim was to evaluate the intracellular pathways involved in the GnRH regulation of apoptosis in BGC-1. Treatment with LA 100nM but not with antide led to an increase in BAX over BCL-2 expression, showing antagonism of antide. All treatments inhibited phospholipase-D (PLD) activity compared to control, implying agonist behavior of antide. Progesterone in vitro production and 3β-hydroxysteroid dehydrogenase (3β-HSD) expression revealed different degrees of luteinization: BGC-1 were immature, whereas CPGB+ were less differentiated than CPGB-. We concluded that LA-induced apoptosis in BGC-1 occurs by activation of the mitochondrial pathway and by inhibition of PLD activity and that antide might work both as an antagonist of the intrinsic pathway and as an agonist of the extrinsic protection pathway by inhibiting PLD activity.

ATF6 knockdown decreases apoptosis, arrests the S phase of the cell cycle, and increases steroid hormone production in mouse granulosa cells

Activating transcription factor 6 (ATF6), a sensor protein located in the endoplasmic reticulum (ER) membrane, is an important factor in the ER stress signaling pathway. ER stress is known to be involved in folliculogenesis, follicular growth, and ovulation; however, the physiological function of ATF6 in mouse granulosa cells remains largely unknown. The aim of this study was to assess the role of ATF6 in mouse granulosa cells with respect to apoptosis, the cell cycle, and steroid hormone production, as well as several key genes related to follicular development, via RNA interference, immunohistochemical staining, real-time quantitative PCR, Western blotting, flow cytometry, terminal deoxynucleotidyltransferase-mediated deoxy-UTP nick end labeling (TUNEL) assay, and ELISA. Immunohistochemical staining revealed that ATF6 was extensively distributed in the granulosa cells of various ovarian follicles and oocytes in adult female mice. FSH or LH treatment significantly increased ATF6 protein levels in mouse granulosa cells. In the meantime, a recombinant plasmid was used to deplete ATF6 successfully using short hairpin RNA-mediated interference technology, which was verified at both the mRNA and protein levels. Flow cytometry and TUNEL assay analysis indicated that ATF6 depletion decreased apoptosis and arrested the S phase of the cell cycle in mouse granulosa cells. Consistent with these results, p53, caspase-3, B cell lymphoma 2 (Bcl-2)-associated X protein, CCAAT-enhancer-binding protein homologous protein, cyclin A1, cyclin B1, and cyclin D2 mRNA expression decreased, whereas Bcl-2 and glucose-regulated protein 78 kDa mRNA expression increased. Interestingly, ATF6 knockdown obviously increased progesterone and estradiol production in mouse granulosa cells. Cytochrome P450 1b1 (Cyp1b1) mRNA levels were downregulated, whereas Cyp11a1, steroidogenic acute regulatory, and Cyp19a1 mRNA levels were upregulated, in keeping with the changes in steroid hormones. Furthermore, ATF6 disruption remarkably increased insulin-like growth factor binding protein4 (Igfbp4) expression and decreased hyaluronan synthase 2 (Has2), prostaglandin-endoperoxide synthase 2 (Ptgs2), and prostaglandin F receptor (Ptgfr) expression in mouse granulosa cells, which are proteins crucial for follicular development. But, after treating with tunicamycin, the levels of Has2, Ptgs2, and Ptgfr increased relatively, whereas Igfbp4 expression decreased. Collectively, these results imply that ATF6, as a key player in ER stress signaling, may regulate apoptosis, the cell cycle, steroid hormone synthesis, and other modulators related to folliculogenesis in mouse granulosa cells, which may indirectly be involved in the development, ovulation, and atresia of ovarian follicles by affecting the physiological function of granulosa cells. The present study extends our understanding and provides new insights into the physiological significance of ATF6, a key signal transducer of ER stress, in ovarian granulosa cells.

p53 activates miR-192-5p to mediate vancomycin induced AKI

Pathogenic role of p53 in AKI remains controversial and the underlying mechanism is unclear. Here, we tested whether the inhibition of p53 may ameliorate vancomycin (VAN) induced acute kidney injury (AKI). Mice with p53 knock out (p53-KO) were resistant to VAN induced AKI, indicated by the analysis of renal function, histology, and apoptosis. Mechanistically, AKI was associated with the upregulation of several known p53 target genes, including Bax and p21, and this association was attenuated in p53-KO mice. Furthermore, the expression of miR-192-5p was significantly decreased in the p53-KO kidney tissues. In human renal tubular epithelial cell line (HK-2), VAN induced p53 accumulation and miR-192-5p expression. Both apoptosis of HK-2 cells and expression of miR-192-5p were also suppressed by pifithrin-α. Anti-miR-192-5p significantly blocked VAN-induced apoptosis and caspase activity in HK-2 cells. Consistently, in vivo inhibition of miR-192-5p also suppressed VAN induced AKI. Thus, we provided clinical and genetic evidence that p53 was associated with the development of VAN induced AKI through upregulation of miR-192-5p.

Granulosa cell apoptosis by impairing antioxidant defense system and cellular integrity in caprine antral follicles post malathion exposure

Toxicological studies have demonstrated the exposure-risk relationship of several pesticides on reproduction of living organisms. To evaluate the role of malathion as a reproductive toxicant, this study aims at assessing the cytological and biochemical changes in the granulosa cells after malathion exposure in dose (1 nM, 10 nM, 100 nM) and time (4 h, 6 h, 8 h) dependent manner. Histomorphological analysis, fluorescence assay, apoptosis quantification, and terminal deoxynucleotidyl transferase d-UTP mediated nick end labeling (TUNEL) assay were done to determine cytological changes, whereas antioxidant enzyme assays were done to measure the oxidative stress in malathion treated ovarian antral follicles. Histological studies exhibited the occurrence of highly condensed or marginated chromatin with fragmented nucleus, pyknosis, loss of membrane integrity, increased empty spaces, and vacuolization in malathion treated granulosa cells. Ethidium bromide/acridine orange (EB/AO) fluorescence staining demonstrated a significant increase in incidence and percentage of apoptosis after malathion exposure (p < 0.001), both between and within the groups. Malathion exposure also resulted in increased DNA fragmentation and decline in both antioxidant enzymes activity namely catalase (CAT) and superoxide dismutase (SOD) in granulosa cells of antral follicles. Moreover, there was found a significant negative correlation between the apoptosis incidence and the level of antioxidant enzymes activity, SOD (r = -0.73 p < 0.01) and CAT (r = -0.80 p < 0.01), in malathion treated ovarian antral follicles. Thus, highlighting the role of DNA fragmentation and declining antioxidant level as a possible mechanism underlying malathion induced reproductive toxicity. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1944-1954, 2016.

The relationship between beta-catenin and apoptosis: A cytological and immunocytochemical examination

Disruption of the adhesive role of beta-catenin by caspases has been reported; however, the relationship between the Wnt/beta-catenin signaling pathway and apoptosis remains unclear. Therefore, we aimed to evaluate squamous epithelial cells in cervicovaginal smears by using cytological and immunocytochemical methods to observe changes in the presence and localization of beta-catenin during apoptosis, death receptor-, and mitochondria-mediated apoptosis. We investigated 224 cervicovaginal smears using the Papanicolaou method. Anti-beta-catenin and anti-cleaved caspase 3, 8, and 9 antibodies were used for immunocytochemical staining. Apoptotic cells were negative for beta-catenin. This showed that the Wnt/beta-catenin signaling pathway was inactive in apoptotic cells. However, beta-catenin showed intense positivity in the membrane, cytoplasm, and nucleus of non-apoptotic epithelial cells around these apoptotic cells. Therefore, the Wnt/beta-catenin signaling pathway was active in non-apoptotic epithelial cells, and this activity in non-apoptotic cells may have been induced by apoptotic cells. A highly significant association between the presence of death receptor-mediated apoptosis and the activity of the Wnt/beta-catenin signaling pathway was also found (P<0.001). In conclusion, the Wnt/beta-catenin signaling pathway was found to be inactive in apoptotic cells, but apoptotic cells may induce the Wnt/beta-catenin signaling pathway in non-apoptotic cells to compensate for a decrease in epithelial cells because of apoptosis in order to maintain epithelial tissue integrity.

RNAi-mediated knockdown of inhibin α subunit increased apoptosis in granulosa cells and decreased fertility in mice

Inhibin α (INHα), a member of TGFβ superfamily, is an important modulator of reproductive function that plays a vital role in follicular changes, cell differentiation, oocyte development, and ultimately in mammalian reproduction. However, the role of inhibin α in female fertility and ovarian function remains largely unknown. To define its role in reproduction, transgenic mice of RNAi-INHα that knock down the INHα expression by shRNAi were used. Inhibin α subunit gene was knocked down successfully at both transcriptional and translational levels by RNAi PiggyBac transposon (Pbi) mediated recombinant pshRNA vectors and purified DNA fragments were microinjected into mouse zygotes. Results showed that transgenic female mice were sub-fertile and exhibited 35.28% reduction in litter size in F1 generation relative to wild type. The decreased litter size associated with the reduction in the number of oocytes ovulated after puberty. Serum INHα level was significantly decreased in both 3 and 6 weeks; whereas, FSH was significantly increased in 3 weeks but not in 6 weeks. Furthermore, suppression of INHα expression significantly promoted apoptosis by up-regulating Caspase-3, bcl2, INHβB and GDF9 and down regulated Kitl and TGFβRIII genes both at transcriptional and translational levels. Moreover, it also dramatically reduced the progression of G1 phase of cell cycle and the number of cells in S phase as determined by flow cytometer. These results indicate that suppression of INHα expression in RNAi-transgenic mice leads to disruption of normal ovarian regulatory mechanism and causes reproductive deficiencies by promoting cellular apoptosis, arresting cellular progression and altering hormonal signaling.

Proliferation, apoptosis and expression of matrix metalloproteinase-9 in human fetal lung

Expression pattern of the Ki-67, caspase-3 and matrix metalloproteinases-9 (MMP-9) factors were immunohistochemically analyzed in 48 human fetal lungs from 12 to 40 weeks of gestation. The number of Ki-67 positive cells in the epithelium of canaliculare (88cells/mm(2)) and sacculare stage (93cells/mm(2)) were significantly higher than in the epithelium of pseudoglandular stage (12cells/mm(2)) (p=0.0008 vs. p=0.003). The number of Ki-67 positive cells in the mesenchyme of canaliculare stage (132cells/mm(2)) was significantly higher than in the mesenchyme of pseudoglandular stage (37cells/mm(2)) (p=0.001). The proliferation of mesenchymal cells was higher than the epithelial cells in all developmental stages, especially in the canaliculare stage (p=0.007). Similarly, the number of caspase-3 positive cells in the epithelium of canalicular stage (13cells/mm(2)) was significantly higher than in the epithelium of pseudoglandular stage (6cells/mm(2)) (p=0.002) with peaks in the conductive epithelium of canalicular stage. The number of caspase-3 positive cells in the mesenchyme of canaliculare stage (3cells/mm(2)) was significantly higher than in the mesenchyme of saccular stage (0cells/mm(2)) (p=0.05). There were no caspase-3 positive cells in the mesenchyme of pseudoglandular stage. However, unlike the Ki-67 expression, mesenchymal cells in comparison to epithelial cells express substantially less caspase-3 in all developmental stages. Up to the saccular stage, the expression of MMP-9 in mesenchymal cells showed a linear increase with most pronounced expression in that stage. The number of MMP-9 positive cells in the mesenchyme of canaliculare (20cells/mm(2)) and sacculare (39cells/mm(2)) stage were significantly higher than in the mesenchyme of pseudoglandular stage (12cells/mm(2)) (p=0.04 vs. p=0.004). The first epithelial cells that express MMP-9 were present only at the alveolar stage. Increased proliferation and apoptosis of the mesenchymal cells of canalicular stage is important for formation of definite structures within the stroma of the lung parenchyma. Although apoptosis in the epithelium is not pronounced as proliferation, it is important for thinning of the epithelium and consequent spread of respiratory tract. However in the saccular stage when mesenchyme disappears, MMP-9 expression is more important for primitive alveoli differentiation.

Is AMH a regulator of follicular atresia?

We discuss the hypothesis that AMH is an intraovarian regulator that inhibits follicular atresia within the human ovary. Several indirect lines of evidence derived from clinical and basic science studies in a variety of different patient populations and model systems collectively support this hypothesis. Evidence presented herein include 1) timing of onset of menopause in women with polycystic ovary syndrome, 2) site of cellular origin and timing of AMH production, 3) AMH's influence on other critical growth factors and enzymes involved in folliculogenesis, and 4) AMH's inhibition of granulosa apoptosis. If this hypothesis is true, it may provide insight for treatment strategies for prevention and treatment of premature ovarian insufficiency, slowing natural ovarian aging, and/or delaying eventual ovarian failure. Such findings may lead to the development of 1) AMH agonists for retarding the onset of menopause and/or as a chemoprotectant prior to cancer therapy and 2) AMH antagonists for the treatment of PCOS.

Constitutive and follicle-stimulating hormone-induced action of somatostatin receptor-2 on regulation of apoptosis and steroidogenesis in bovine granulosa cells

In the present study, we employed primary bovine culture of granulosa cells (GCs) as a cellular model to study the potential involvement of somatostatin receptor 2 (SSTR2) in ovarian function. The results showed that bovine GCs expressed SST2 receptor and further found that SSTR2 was possibly regulated by follicle-stimulating hormone (FSH), as a significant increase in protein level of SSTR2 was observed in FSH-treated GCs. For further analysis, endogenous SSTR2 expression was disrupted using small inhibitory RNA (siRNA) and the efficacy of differential silencing of endogenous SSTR2 expression was measured both at transcriptional and translational levels. Transient blockage of SSTR2 evidenced its constitutive action on GCs, as it significantly increased level of cAMP (2.4-folds) and basal progesterone production (∼2-fold, P<0.05) with significant increase (P<0.05) in mRNA levels of StAR and P450ssc without altering estradiol concentration and aromatase mRNA expression. Furthermore, silencing of SSTR2 reduced GCs apoptosis (52.5%, P<0.05) and increased cell proliferation, which was further corroborated by up-regulation in protein expressions of B-cell leukemia/lymphoma 2 (Bcl-2), inhibition of caspase3 and mRNA level of bcl2-associated-X protein (Bax). These results provide evidence that SSTR2 subtype controls GCs apoptosis, proliferation and hormonal secretions through selective constitutive action, independently of somatostatin (SST). Given the local inhibitory actions of SSTR2 on the gonads, we further found that apoptosis in ssRNAi-2 transfected cells decreased (6.8% vs 1.9%, P<0.05) more strongly on FSH treatment. Apoptotic protein expressions and steroid hormone mRNA levels were correlated with a relative decrease in apoptosis and increase in progesterone production. Our results suggest that SSTR2 may play a crucial role as a local inhibitor of FSH action on GCs apoptosis and steroidogenesis.

Transcriptome profiling of granulosa cells from bovine ovarian follicles during atresia

Background

The major function of the ovary is to produce oocytes for fertilisation. Oocytes mature in follicles surrounded by nurturing granulosa cells and all are enclosed by a basal lamina. During growth, granulosa cells replicate and a large fluid-filled cavity (the antrum) develops in the centre. Only follicles that have enlarged to over 10 mm can ovulate in cows. In mammals, the number of primordial follicles far exceeds the numbers that ever ovulate and atresia or regression of follicles is a mechanism to regulate the number of oocytes ovulated and to contribute to the timing of ovulation. To better understand the molecular basis of follicular atresia, we undertook transcriptome profiling of granulosa cells from healthy (n = 10) and atretic (n = 5) bovine follicles at early antral stages (< 5 mm).

Results

Principal Component Analysis (PCA) and hierarchical classification of the signal intensity plots for the arrays showed primary clustering into two groups, healthy and atretic. These analyses and size-frequency plots of coefficients of variation of signal intensities revealed that the healthy follicles were more heterogeneous. Examining the differentially-expressed genes the most significantly affected functions in atretic follicles were cell death, organ development, tissue development and embryonic development. The overall processes influenced by transcription factor gene TP53 were predicted to be activated, whereas those of MYC were inhibited on the basis of known interactions with the genes in our dataset. The top ranked canonical pathway contained signalling molecules common to various inflammatory/fibrotic pathways such as the transforming growth factor-β and tumour necrosis factor-α pathways. The two most significant networks also reflect this pattern of tissue remodelling/fibrosis gene expression. These networks also contain molecules which are present in the canonical pathways of hepatic fibrosis/hepatic stellate cell activation and transforming growth factor-β signalling and were up regulated.

Conclusions

Small healthy antral follicles, which have a number of growth outcomes, exhibit greater variability in gene expression, particularly in genes associated with cell division and other growth-related functions. Atresia, on the other hand, not only involves cell death but clearly is an active process similar to wound healing.

The expression patterns of pro-apoptotic and anti-apoptotic factors in human fetal and adult ovary

The influence of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins on the cell death (caspase-3, TUNEL) of different ovarian cell lineages was immunohistochemically analyzed in six fetal and five adult human ovaries in order to disclose possible mechanisms of cell number control. Mild to moderate expression of Bcl-2 characterized ovarian surface epithelium, follicular cells and oocytes of 15 and 22 week human ovaries, while expression of Bax and caspase-3 gradually increased in all ovarian cell populations, except caspase-3 in the ovarian surface epithelium. Different levels of Bax and Bcl-2 proteins co-expression characterized fetal ovarian cells, while TUNEL and caspase-3 co-expression was found only in some of them. In adult ovaries, Bcl-2 was moderately and Bax strongly expressed in the surface ovarian epithelium and stroma. Bcl-2 and Bax expression in granulosa and theca interna cells varied depending on the stage of follicular atresia. Caspase-3 apoptotic cells characterized granulosa cells of adult atretic follicles. Our results indicate that intracellular levels of Bcl-2 and Bax protein might regulate the final destiny of developing germ cells. Caspase-3 dependent apoptosis seems to be the most important, but not the only cell death pathway in ovaries. In adult ovaries, caspase-dependent cell death characterized granulosa cells, but not the germ cells.

Expression of antiapoptosis gene survivin in luteinized ovarian granulosa cells of women undergoing IVF or ICSI and embryo transfer: clinical correlations

BACKGROUND

The purpose of the study was to determine the incidence of survivin gene expression in human granulosa cells during ovarian stimulation in Greek women with normal FSH levels, undergoing IVF or ICSI and to discover any correlation between levels of gene expression and clinical parameters, efficacy of ovulation or outcomes of assisted reproduction.

METHODS

Twenty nine women underwent ovulation induction for IVF or ICSI and ET with standard GnRH analogue-recombinant FSH protocol. Infertility causes were male and tubal factor. Cumulus-mature oocyte complexes were denuded and the granulosa cells were analyzed for each patient separately using quantitative reverse transcription polymerase chain reaction analysis for survivin gene expression with internal standard the ABL gene.

RESULTS

The ABL and survivin mRNA were detected in granulosa cells in 93.1%. The expression levels of survivin were significantly lower in normal women (male infertility factor) compared to women with tubal infertility factor (p = 0.007). There was no additional statistically significant correlation between levels of survivin expression and estradiol levels or dosage of FSH for ovulation induction or number of dominant follicles aspirated or number of retrieved oocytes or embryo grade or clinical pregnancy rates respectively.

CONCLUSIONS

High levels of survivin mRNA expression in luteinized granulosa cells in cases with tubal infertility seem to protect ovaries from follicular apoptosis. A subpopulation of patients with low levels of survivin mRNA in granulosa cells might benefit with ICSI treatment to bypass possible natural barriers of sperm-oocyte interactions.

Evidence for a genomic mechanism of action for progesterone receptor membrane component-1

Progesterone receptor membrane component 1 (PGRMC1) is highly expressed in the granulosa and luteal cells of rodent and primate ovaries. Interestingly, its molecular weight as assessed by Western blot is dependent on its cellular localization with a ≈27kDa form being detected in the cytoplasm and higher molecular weight forms being detected in the nucleus. The higher molecular weight forms of PGRMC1 are sumoylated suggesting that they are involved in regulating gene transcription, since sumoylation of nuclear proteins often is associated with regulation of transcriptional activity of the sumoylated protein. In order to identify a set of candidate genes that are regulated by PGRMC1, a human granulosa/luteal cell line (hGL5 cells) was treated with PGRMC1 siRNA and changes in gene expression monitored by microarray analysis. The microarray analysis revealed that PGRMC1 generally functioned as a repressor of transcription, since depletion of PGRMC1 resulted in a disproportionate increase in the number of transcripts. Moreover, a pathway analysis implicated PGRMC1 in the regulation of apoptosis, which is consistent with PGRMC1's known biological action. More importantly these results support the concept that PGRMC1 influences gene transcription. Additional studies reveal that progesterone (P4) acting through a PGRMC1-dependent mechanism suppresses the activity of the transcription factor, Tcf/Lef, thereby identifying one molecular pathway through which P4-PGRMC1 can regulate gene transcription and ultimately apoptosis.

Follicular populations, recruitment and atresia in the ovaries of different strains of mice

Follicular atresia is a key event in the selection of the ovulatory follicles and occurs during all developmental stages. The aims of the study were to evaluate the follicular population as well as the rates of follicular recruitment and atresia in different strains of mice. Ovaries were obtained from four strains of mice: G1/ Swiss, G2/ F1 Swiss×C57BL/6, G3/ inbred strain C57BL/6, and G4/ F1 C57BL/6×Swiss. All mice used in the study were 60 days old. Ovaries collected from the mice were fixed and processed for histological analysis. The G2 ovaries were also used to examine immunolocalization of active caspase-3. The pimordial follicle population was smaller in G3 mice than in G1, G2 and G4 groups (7 565±1 845 vs. 17 180±3 159, 14 785±3 319 and 13 325±2 685, respectively; p<0.05). The rate of follicular recruitment in G3, however, was higher than in the other groups (29.2% vs. 18.2%, 17.3% and 13.0% in G1, G2 and G4, respectively; p<0.05), resulting in a similar (p>0.05) number of antral follicles among groups. The small follicular pool in G3 mice was also associated with a lower rate of follicular atresia (11.4% vs. 17.2%, 16.7% and 13.6% for G3, G1, G2 and G4, respectively; p<0.05). The number of follicles stained with active caspase-3 was higher (p<0.05) during the final stage of preantral folliculogenesis than in other stages of follicular development suggesting that apoptosis in mice occurs earlier in comparison to large animals. Thus, it was concluded that differences in follicle reservoir among mice strains are compensated by an increased rate of follicular recruitment and a decreased rate of follicular atresia; and atresia occurs in mice mainly at the end of the preantral stage of folliculogenesis.

Follicular atresia in the prepubertal spiny mouse (Acomys cahirinus) ovary

This study was designed to determine follicular atresia in the newborn and the prepubertal spiny mouse. We analyzed the processes of follicle loss using classical markers of apoptosis (TUNEL reaction, active caspase-3) and autophagy (Lamp1). Numerous small clear vacuoles and autophagosomes as well as strong Lamp1 staining were observed in dying oocytes of all follicle types, especially of the primordial and primary ones. Active caspase 3 and the TUNEL reaction were detected only in the granulosa cells of large secondary and antral follicles. The expression of apoptosis and autophagy markers was also changing during the prepubertal period. Western blot analysis indicated that at the moment of birth, females undergo an increased rate of follicular atresia mediated by autophagy, while apoptosis is the dominant form of ovarian atresia in consecutive postnatal days. On the basis of these observations, we concluded that apoptosis and autophagy are involved in follicular atresia and these processes are cell and developmental stage-specific.

Intra-uterine growth restriction is associated with increased apoptosis and altered expression of proteins in the p53 pathway in villous trophoblast

Intrauterine growth restriction (IUGR) affects 3-8% of pregnancies and is associated with altered cell turnover in the villous trophoblast, an essential functional cell type of the human placenta. The intrinsic pathway of apoptosis, particularly p53, is important in regulating placental cell turnover in response to damage. We hypothesised that expression of proteins in the p53 pathway in placental tissue would be altered in IUGR. Expression of constituents of the p53 pathway was assessed using real-time PCR, Western blotting and immunohistochemistry. p53 mRNA and protein expression was increased in IUGR, which localised to the syncytiotrophoblast. Similar changes were noted in p21 and Bax expression. There was no change in the expression of Mdm2, Bak and Bcl-2. The association between altered trophoblast cell turnover in IUGR and increased p53 expression is reminiscent of that following exposure to hypoxia. These observations provide further insight into the potential pathogenesis of IUGR. Further research is required to elicit the role and interactions of p53 and its place in the pathogenesis of IUGR.