Peroxisome proliferator-activated receptors (PPARs) and ovarian function--implications for regulating steroidogenesis, differentiation, and tissue remodeling

Piperine's potential in treating polycystic ovarian syndrome explored through in-silico docking

Polycystic Ovarian Syndrome (PCOS) is a multifaceted metabolic and hormonal condition that impacts women in their procreative ages, identified by ovarian dysfunction, hyperandrogenaemia overweight and insulin insensitivity. The piperine, an important alkaloid compound of black pepper has shown promise in modulating various physiological processes. In this work, employed computational docking studies to explore the potential of piperine as a treatment for PCOS. Utilizing computational methods, we analyzed the binding interactions between piperine and key molecular targets implicated in PCOS pathogenesis, including hyperandrogenism, and "oligomenorrhea. The network pharmacology analysis report found 988 PCOS-related genes, 108 hyperandrogenism-related genes, and 377 oligomenorrhea-related genes, and we finally shortlisted 5 common genes in PCOS, hyperandrogenism, and "oligomenorrhea": NR3C1, PPARG, FOS, CYP17A1, and H6PD. Our results reveal favorable binding affinities with PPARG (-8.34 Kcal/mol) and H6PD (-8.70 Kcal/mol) and interaction patterns, suggesting the potential of piperine to modulate these targets. Moreover, the reliability of the piperine-target interactions was revealed by molecular simulations studies. These findings support further experimental investigations to validate the therapeutic efficacy of piperine in PCOS management. The integration of computational approaches with experimental studies has the potential to lay the groundwork for the creation of new therapies specifically targeting PCOS and related endocrine disorders.

Exposure to environmental doses of DEHP causes phenotypes of polycystic ovary syndrome

Globally, approximately 6-20% of women who are of reproductive age suffer from polycystic ovary syndrome (PCOS), with environmental factors believed to be significant contributors. Di-2-ethylhexyl phthalate (DEHP) is known to be an endocrine disruptor, and is also suspected of being associated with the occurrence of PCOS, but in vivo studies to verify this association are lacking. In this study, female SD rats were exposed to DEHP at levels of 0.1, 1.0, and 10mg/kg/d, which are comparable to daily human exposure, to explore its potential role in the development of PCOS. The findings indicated that DEHP exposure reduced ovarian and uterine coefficients, decreased accumulation of primordial follicles, increased the prevalence of atretic and cystic follicles and fibrosis in ovarian tissues, altered serum hormone levels, elevated blood glucose levels and insulin resistance, disrupted the endocrine system and resulted in significant oxidative damage in the ovarian tissues. These results imply that DEHP exposure may cause lesions resembling PCOS to develop. By analyzing the differential expression of the proteome, and using GO and KEGG enrichment analyses, we found they were mainly enriched in the metabolic pathway and in the PPAR signaling pathway. We confirmed that activation of the PPARγ signaling pathway caused by DEHP exposure, is related to the emergence of PCOS-like lesions. This research provides direct in vivo experimental evidence for the association between DEHP exposure and PCOS.

Per- and Polyfluoroalkyl Substances (PFASs) and Their Potential Effects on Female Reproductive Diseases

Per- and polyfluoroalkyl substances (PFASs) are a class of anthropogenic organic compounds widely present in the natural and human living environments. These emerging persistent pollutants can enter the human body through multiple channels, posing risks to human health. In particular, exposure to PFASs in women may cause a series of reproductive health hazards and infertility. Based on a review of the existing literature, this study preliminarily summarizes the effects of PFAS exposure on the occurrence and development of female reproductive endocrine diseases, such as polycystic ovary syndrome (PCOS), endometriosis, primary ovarian insufficiency (POI), and diminished ovarian reserve (DOR). Furthermore, we outline the relevant mechanisms through which PFASs interfere with the physiological function of the female ovary and finally highlight the role played by nutrients in reducing the reproductive health hazards caused by PFASs. It is worth noting that the physiological mechanisms of PFASs in the above diseases are still unclear. Therefore, it is necessary to further study the molecular mechanisms of PFASs in female reproductive diseases and the role of nutrients in this process.

Effects of Per- and Polyfluoroalkylated Substances on Female Reproduction

Per- and poly-fluoroalkylated substances (PFAS) are a large group of chemicals that persist both in the environment and in the body. Legacy PFAS, e.g., perfluorooctanoic acid and perfluorooctane sulfonic acid, are implicated as endocrine disruptors and reproductive and developmental toxicants in epidemiological and animal model studies. This review describes female reproductive outcomes of reported studies and includes where associative relationships between PFAS exposures and female reproductive outcomes have been observed as well as where those are absent. In animal models, studies in which PFAS are documented to cause toxicity and where effects are lacking are described. Discrepancies exist in both human and animal studies and are likely attributable to human geographical contamination, developmental status, duration of exposure, and PFAS chemical identity. Similarly, in animal investigations, the model used, exposure paradigm, and developmental status of the female are important and vary widely in documented studies. Taken together, support for PFAS as reproductive and developmental toxicants exists, although the disparity in study conditions and human exposures contribute to the variation in effects noted.

Perfluorooctane sulfonate (PFOS) induces apoptosis and autophagy by inhibition of PI3K/AKT/mTOR pathway in human granulosa cell line KGN

Perfluorooctane sulfonate (PFOS) is recognized as an environmental endocrine disruptor with widespread use in industrial manufacturing and daily life, contributing to various public health concerns. However, the precise impacts of PFOS on the ovary and its regulatory mechanisms remain unclear. This study aims to delineate the ovarian toxicity of PFOS and scrutinize its effects on apoptosis and autophagy through modulation of the PI3K/AKT/mTOR pathway in the human granulosa cell line (KGN). Cell viability, assessed via the Cell Counting Kit-8 (CCK8), revealed a dose-dependent reduction in cell viability upon PFOS exposure. Flow cytometry analysis demonstrated an elevated proportion of apoptotic cells following PFOS treatment. Western blot analyses unveiled increased expression of Bax, Cyt c, cleaved caspase-9, and LC3-II/I, coupled with decreased expression of Bcl-2 and p62. Transmission electron microscopy (TEM) observations illustrated a heightened number of autophagosomes induced by PFOS. Molecular docking investigations, in conjunction with Western blot experiments, substantiated PFOS's significant inhibition of the PI3K/AKT/mTOR signaling pathway. These findings collectively underscore that PFOS induces apoptosis and autophagy in KGN cells through modulation of the PI3K/AKT/mTOR pathway, providing experimental evidence for PFOS-induced ovarian toxicity and elucidating the underlying regulatory mechanisms in KGN cells.

Progestin and adipoQ receptor 7 (PAQR7) mediate the anti-apoptotic effect of P4 on human granulosa cells and its deficiency reduces ovarian function in female mice

PURPOSE

PAQR7 plays a key role in cell apoptosis as a progesterone membrane receptor. The physiological mechanism of PAQR7 in ovarian function and its anti-apoptotic action in mammals remain poorly understood.

METHODS

We first added 0.2 µM aminoglutethimide (AG), an inhibitor of endogenous progesterone (P4) secretion, and transfected siPAQR7 co-incubated with P4 in human KGN cells to identify granulosa cell apoptosis, respectively. Additionally, we used Paqr7 knockout (PAQR7 KO) mice to assess the role of PAQR7 in the ovary.

RESULTS

The PAQR7 deficiency significantly increased apoptosis of KGN cells, and this significant difference disappeared following P4 supplementation. The Paqr7-/- female mice showed a prolonged estrous cycle, reduced follicular growth, increased the number of atresia follicles, and decreased the concentrations of E2 and AMH. The litters, litter sizes, and spontaneous ovulation in the Paqr7-/- mice were significantly decreased compared with the Paqr7+/+ mice. In addition, we also found low expression of PAQR7 in GCs from human follicular fluids of patients diagnosed with decreased ovarian reserve (DOR) and ovaries of mice with a DOR-like phenotype, respectively.

CONCLUSIONS

The present study has identified that PAQR7 is involved in mouse ovarian function and fertilization potential. One possible mechanism is mediating the anti-apoptotic effect of P4 on GC apoptosis via the BCL-2/BAX/CASPASE-3 signaling pathway. The mechanism underlying the effect of PAQR7 on ovarian development and aging remains to be identified.

Transcriptome profiling reveals transcriptional regulation of Protegrin-1 on immune defense and development in porcine granulosa cells

Protegrin-1 (PG1) is an antimicrobial peptide (AMP) that has garnered increasing attention due to its potent immune defense activity. Our previous studies demonstrated the ability of PG1 to enhance proliferation and inhibit apoptosis of porcine granulosa cells (GCs) under oxidative stress. GCs play a crucial role in ovary follicular development. However, the specific function and underlying mechanisms of AMP in follicular development still need further elucidation. The present study aimed to comprehensively explore the biological effects of PG1 on porcine GCs using transcriptome profiling by RNA sequencing technology. Isolated GCs were incubated with or without PG1 for 24 h and transcriptome-wide analysis was exerted to identify differentially expressed genes (DEGs). The results of expression analysis revealed 1,235 DEGs, including 242 up-regulated genes and 993 down-regulated genes (|log2 (FoldChange)| > 1; adjusted P-value < 0.05). The expression levels of 7 selected DEGs were validated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) analysis, which was consistent with the RNA-sequencing data. Among the significant DEGs, several genes associated with GC function and ovarian follicle development were identified, such as estrogen receptor 2 (ESR2), growth and differentiation factor 6 (GDF6), cell division cycle 20 homolog (CDC20), Notch3, ephrin and Eph receptor system, Egl nine homolog 3 (EGLN3), and BCL2 like 14 (BCL2L14). Gene Ontology (GO) analysis revealed that the top three significant GO terms were inflammatory response, defense response, and granulocyte migration. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis presented that DEGs were mainly enriched in the immune system, infectious disease, signaling molecules and interaction, and immune disease. Furthermore, Ingenuity Pathway Analysis (IPA) predicted that the top activated pathway was Liver X Receptor (LXR)/ Retinoid X Receptor (RXR) Activation which is known to be associated with female reproduction. Predicted protein-protein interactions (PPIs) analysis identified complement C3 (C3) as the top node with the highest degree of network connection and revealed that DEGs in the sub-networks were involved in cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, chemokine signaling pathway, and metabolic process. In conclusion, this study expanded the understanding of the effects of PG1 on porcine GCs at the transcriptomic level and provided a theoretical basis for further investigation into the role of PG1 in immune defense and mammalian ovarian follicular development.

RXR Agonists Enhance Lenalidomide Anti-Myeloma Activity and T Cell Functions while Retaining Glucose-Lowering Effect

Retinoid X receptor (RXR) heterodimerizes with the PPAR nuclear hormone receptor and regulates its downstream events. We investigated the effects of RXR agonists (LG100754, bexarotene, AGN194204, and LG101506) on lenalidomide's anti-myeloma activity, T cell functions, and the level of glucose and lipids in vivo. Genetic overexpression and CRISPR/Cas9 knockout experiments were conducted in multiple myeloma (MM) cell lines and Jurkat T cell lines to determine the roles of CRBN in RXR-agonist mediated effects. A xenograft mouse model of MM was established to determine the combination effect of LG100754 and lenalidomide. The combination of RXR agonists and lenalidomide demonstrated synergistic activity in increasing CRBN expression and killing myeloma cells. Mechanistically, the RXR agonists reduced the binding of PPARs to the CRBN promoter, thereby relieving the repressor effect of PPARs on CRBN transcription. RXR agonists downregulated the exhaustion markers and increased the activation markers of Jurkat T cells and primary human T cells. Co-administration of LG100754 and lenalidomide showed enhanced anti-tumor activity in vivo. LG100754 retained its glucose- and lipid-lowering effects. RXR agonists demonstrate potential utility in enhancing drug sensitivity and T-cell function in the treatment of myeloma.

miR-4433a-3p promotes granulosa cell apoptosis by targeting peroxisome proliferator-activated receptor alpha and inducing immune cell infiltration in polycystic ovarian syndrome

BACKGROUND

Granulosa cell (GC) proliferation and apoptosis are critical events of the ovum energy supply, which lead to follicular growth retardation or atresia, and various ovulatory obstacles, eventually resulting in the development of ovarian disorders such as polycystic ovarian syndrome (PCOS). Apoptosis and dysregulated miRNA expression in GCs are manifestations of PCOS. miR-4433a-3p has been reported to be involved in apoptosis. However, there is no study reporting the roles of miR-4433a-3p in GC apoptosis and PCOS progression.

METHODS

miR-4433a-3p and peroxisome proliferator-activated receptor alpha (PPAR-α) levels in GCs of PCOS patients or in tissues of a PCOS rat model were examined by quantitative polymerase chain reaction and immunohistochemistry. Bioinformatics analyses and luciferase assays were used to examine the association between miR-4433a-3p and PPAR-α, as well as PPAR-α and immune cell infiltration, in PCOS patients.

RESULTS

miR-4433a-3p expression in GCs of PCOS patients was increased. miR-4433a-3p overexpression inhibited the growth of the human granulosa-like tumor cell line (KGN) and promoted apoptosis, while co-treatment with PPAR-α and miR-4433a-3p mimic rescued miR-4433a-3p-induced apoptosis. PPAR-α was a direct target of miR-4433a-3p and its expression was decreased in PCOS patients. PPAR-α expression was also positively correlated with the infiltration of activated CD4+ T cells, eosinophils, B cells, gamma delta T cells, macrophages, and mast cells, but negatively correlated with the infiltration of activated CD8+ T cells, CD56+ bright natural killer cells, immature dendritic cells, monocytes, plasmacytoid dendritic cells, neutrophils, and type 1 T helper cells in PCOS patients.

CONCLUSION

The miR-4433a-3p/PPAR-α/immune cell infiltration axis may function as a novel cascade to alter GC apoptosis in PCOS.

Long-term exposure to di(2-ethylhexyl) phthalate, diisononyl phthalate, and a mixture of phthalates alters estrous cyclicity and/or impairs gestational index and birth rate in mice

Phthalates are found in plastic food containers, medical plastics, and personal care products. However, the effects of long-term phthalate exposure on female reproduction are unknown. Thus, this study investigated the effects of long-term, dietary phthalate exposure on estrous cyclicity and fertility in female mice. Adult female CD-1 mice were fed chow containing vehicle control (corn oil) or 0.15-1500 ppm of di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), or a mixture of phthalates (Mix) containing DEHP, DiNP, benzyl butyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, and diethyl phthalate. Measurements of urinary phthalate metabolites confirmed effective delivery of phthalates. Phthalate consumption for 11 months did not affect body weight compared to control. DEHP exposure at 0.15 ppm for 3 and 5 months increased the time that the mice spent in estrus and decreased the time the mice spent in metestrus/diestrus compared to control. DiNP exposure (0.15-1500 ppm) did not significantly affect time in estrus or metestrus/diestrus compared to control. Mix exposure at 0.15 and 1500 ppm for 3 months decreased the time the mice spent in metestrus/diestrus and increased the time the mice spent in estrus compared to control. DEHP (0.15-1500 ppm) or Mix (0.15-1500 ppm) exposure did not affect fertility-related indices compared to control. However, long-term DiNP exposure at 1500 ppm significantly reduced gestational index and birth rate compared to control. These data indicate that chronic dietary exposure to phthalates alters estrous cyclicity, and long-term exposure to DiNP reduces gestational index and birth rate in mice.

The Role of Peroxisome Proliferator-Activated Receptors in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) constitutes the most common endocrine disorder in women of reproductive age. Patients usually suffer from severe menstrual irregularities, skin conditions, and insulin resistance-associated health conditions. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptor proteins that regulate gene expression. In order to investigate the role of PPARs in the pathophysiology of PCOS, we conducted a literature review using the MEDLINE and LIVIVO databases and were able to identify 74 relevant studies published between 2003 and 2023. Different study groups reached contradictory conclusions in terms of PPAR expression in PCOS. Interestingly, numerous natural agents were found to represent a novel, potent anti-PCOS treatment alternatives. In conclusion, PPARs seem to play a significant role in PCOS.

Dietary n-3 PUFA augments pre-ovulatory follicle turnover and prolificacy in well-fed ewes

The present study evaluated the effect of dietary supplementation with n-3 polyunsaturated fatty acids (PUFA) on preovulatory follicle (POF) turnover, prolificacy, and endocrine and metabolic milieu in Malpura sheep. Fifty cyclic ewes with 3-3.5 body condition scores on a five-point scale were allocated equally to two groups (n = 25) following estrus synchronization and were supplemented with 0.6 mL/kg body weight of n-3 PUFA-rich fish oil (FO) or palm oil (PO) as control, for 60 d following an acclimatization period of 7 d. All ewes were mated with sexually active rams at the end of the supplementation period. On ultrasonographic ovarian scanning at the last fourth estrus, the mean number of POFs was 77.8% greater (P < 0.01) in FO ewes than in the PO ewes. The proportion of ewes with multiple ovulations two months after the beginning of supplementation was 56% in the FO group as compared to 8% in the PO group. The number of fetuses was 46% higher (P < 0.01) in the FO than in the PO ewes at d 45 of gestation. At lambing, the twinning percent in the FO ewes was three times greater than in the PO ewes (27.3 vs. 9.1%). Plasma cholesterol, estradiol, and insulin concentrations were lower (P < 0.01) in ewes fed with FO than those offered PO group at the end of the feeding period. It was concluded that the dietary supplementation of n-3 PUFA-rich FO in well-fed Malpura ewes improved the number of follicles and ovulation rate which led to an increased prolificacy, accompanied by a reduction of plasma cholesterols, estradiol, and insulin.

Potential therapeutic drug targets and pathways prediction for premature ovarian insufficiency -Based on network pharmacologic method

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of premature ovarian insufficiency (POI) is gradually increasing, the proportion is rising especially in female infertility patients. The risk of death of POI patients with cardiovascular disease also increases significantly. The cause of POI is complex and unclear, and clinical treatment is still in the exploratory stage, are two major constraints of treating POI. Traditional Chinese medicine (TCM) is widely used in the treatment of POI, and it is a good way to combine the development of modern new drugs with the help of TCM to predict the therapeutic targets.

AIM OF THE STUDY

In this study, four herbs commonly used in clinical treatment of POI, namely Radix Paeoniae, Polygonatum sibiricum, Rehmannia glutinosa and Eucommia ulmoides were selected to predict their mechanism in the treatment of POI, using network pharmacology methods. Then verify the predicted targets by animal test. Aim to find more effective POI potential core treatment targets and main pathways.

MATERIALS AND METHODS

We screened the active ingredients of drugs from the TCM System Pharmacology Analysis Platform (TCMSP), Performed target prediction of active ingredients from databases such as SwissTargetPrediction and compare and analyze the POI-related targets retrieved from them to obtain potential targets for drug treatment of POI. Used STRING database to construct a protein interaction network, Cytoscape 3.7.2 software to construct an active ingredient-target-pathway network, and DAVID database to conduct the Kyoto Encyclopedia of Genes and Genomes (KEGG) on the intersection targets and gene ontology (GO) enrichment analysis.

RESULTS

The result is: there were 25 key targets for the treatment of POI with Radix Paeoniae Alba, 31 for the treatment of POI by Eucommia ulmoides, 28 for the treatment of POI by Polygonatum sibiricum, and 8 key targets for the treatment of Rehmannia glutinosa. The intersection targets of four herbs were defined as the core targets, which are CYP19A1, EGF, ESR1, ESR2, MDM2, AR, PCYP17A1, PPARG. Four Chinese herbs treat POI mainly through HIF-1 signaling pathway, PI3K-Akt signaling pathway, FoxO signaling pathway, Estrogen signaling pathway etc. A mouse model of POI was constructed based on the results of network pharmacology to verify the predicted targets. The results showed that the protein expression of the core target changed, and the estrogen level was increased by reducing the expression of peroxisome proliferator-activated receptor gamma (PPARG).

CONCLUSIONS

This study predicts the mechanism of multiple herbs in the treatment of POI, screens out more potential therapeutic drug targets and main pathways of POI treatment and provides new ideas for the subsequent development of POI therapeutic drugs.

In vitro effects of PPAR gamma ligands on gene expression in corpus luteum explants in non-pregnant pigs - Transcriptome analysis

The corpus luteum (CL) is a temporary endocrine structure in the female ovaries that develops cyclically in mature females during luteinization. This study aimed to determine the in vitro effects of peroxisome proliferator-activated receptor gamma (PPARγ) ligands on the transcriptomic profile of the porcine CL in the mid- and late-luteal phase of the estrous cycle using RNA-seq technology. The CL slices were incubated in the presence of PPARγ agonist - pioglitazone or antagonist - T0070907. We identified 40 differentially expressed genes after treatment with pioglitazone and 40 after treatment with T0070907 in the mid-luteal phase as well as 26 after pioglitazone and 29 after T0070907 treatment in the late-luteal phase of the estrous cycle. In addition, we detected differences in gene expression between the mid- and late-luteal phase without treatment (409 differentially expressed genes). This study revealed a number of novel candidate genes that may play a role in controlling the function of CL by regulating signaling pathways related to ovarian steroidogenesis, metabolic processes, cell differentiation, apoptosis, and immune responses. These findings become a basis for further studies to explain the mechanism of PPARγ action in the reproductive system.

Effect of PFOA exposure on diminished ovarian reserve and its metabolism

Owing to its difficulty in degrading and ease of accumulation in the body, perfluorooctanoic acid (PFOA) has a detrimental effect on reproduction. This study aimed to examine the effect of PFOA concentration in follicular fluid during ovulation stimulation on embryo quality and the impact of PFOA exposure on the metabolic components of follicular fluid. This was a single-center prospective study that included 25 patients with diminished ovarian reserve (DOR), 25 with normal ovarian reserve (NOR), and 25 with polycystic ovary syndrome (PCOS). Follicular fluid samples were analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry. We demonstrated that the PFOA levels of follicular fluid in the DOR group were higher than those in the NOR group and PCOS group (P < 0.05). PFOA concentration in the PCOS group was negatively correlated with high-quality embryos (P < 0.05). To gain more insight into the impact of PFOA on the metabolic composition of follicular fluid, we classified the DOR group based on the PFOA concentration, for which metabolomic analysis was performed. In the high-concentration PFOA group, there was an increase and a decrease in three and nine metabolites, respectively, compared to that in the low-concentration group. These results suggest that PFOA may alter the metabolic composition of follicular fluid, thus, affecting ovarian reserve function.

Exposure assessment of aryl-organophosphate esters based on specific urinary biomarkers and their associations with reproductive hormone homeostasis disruption in women of childbearing age

The effects of aryl-organophosphate esters (aryl-OPEs) on female reproduction health are still unclear owing to the lack of specific exposure biomarkers. Here, we analyzed the hydroxylated metabolites of three aryl-OPEs (phenyl diphenyl phosphate [TPhP], 2-ethylhexyl diphenyl phosphate [EHDPP], and tricresyl phosphate [TCrP]) and diphenyl phosphate (DPhP) in urine samples from 913 women of childbearing age, and explored the association between exposure to the aryl-OPEs and reproductive hormone levels. The detection frequencies of 2-ethyl-5-hydroxyhexyl diphenyl phosphate (5-OH-EHDPP), phenyl di-p-tolyl phosphate (4-OH-MDTP), and 4-hydroxyphenyl diphenyl phosphate (4-OH-TPhP) were 94.6 %, 93.3 %, and 84.2 %, respectively. Multivariate linear regression analyses revealed that the quartiles of 4-OH-TPhP were positively associated with the progesterone (P4) level (p-trend = 0.008), and the P level in the highest quartile of 5-OH-EHDPP was 7.2 % (95 % CI, 5.7 % to 8.7 %) higher than that in the lowest quartile. The 17β-estradiol levels in the highest quartiles of 4-OH-TPhP and 5-OH-EHDPP were 15.0 % (95 % CI, 13.7 % to16.1 %) and 5.9 % (95 % CI, 15.7 % to 16.1 %) lower than those in the lowest quartiles, respectively. The anti-Müllerian hormone level linearly increased across the quartiles of 4-OH-MDTP (p-trend = 0.036), and the follicle-stimulating hormone exhibited the opposite trend (p-trend = 0.0047). These results indicate that aryl-OPEs may disrupt hormone homeostasis using their specific biomarkers and may negatively affect female reproduction.

Cannabinoids and PPAR Ligands: The Future in Treatment of Polycystic Ovary Syndrome Women with Obesity and Reduced Fertility

Cannabinoids (CBs) are used to treat chronic pain, chemotherapy-induced nausea and vomiting, and multiple sclerosis spasticity. Recently, the medicinal use of CBs has attracted increasing interest as a new therapeutic in many diseases. Data indicate a correlation between CBs and PPARs via diverse mechanisms. Both the endocannabinoid system (ECS) and peroxisome proliferator-activated receptors (PPARs) may play a significant role in PCOS and PCOS related disorders, especially in disturbances of glucose-lipid metabolism as well as in obesity and fertility. Taking into consideration the ubiquity of PCOS in the human population, it seems indispensable to search for new potential therapeutic targets for this condition. The aim of this review is to examine the relationship between metabolic disturbances and obesity in PCOS pathology. We discuss current and future therapeutic interventions for PCOS and related disorders, with emphasis on the metabolic pathways related to PCOS pathophysiology. The link between the ECS and PPARs is a promising new target for PCOS, and we examine this relationship in depth.

An Alkaloid from a Highly Invasive Seaweed Increases the Voracity and Reproductive Output of a Model Fish Species

The invasive macroalga Caulerpa cylindracea has spread widely in the Mediterranean Sea, becoming a favorite food item for native fish for reasons yet unknown. By using a combination of behavioral, morphological, and molecular approaches, herein we provide evidence that the bisindole alkaloid caulerpin, a major secondary metabolite of C. cylindracea, significantly increases food intake in the model fish Danio rerio, influencing the regulation of genes involved in the orexigenic pathway. In addition, we found that the compound improves fish reproductive performance by affecting the hypothalamus-pituitary-gonadal axis. The obtained results pave the way for the possible valorization of C. cylindracea as a sustainable source of a functional feed additive of interest to face critical challenges both in aquaculture and in human nutrition.

Adipose tissue and ovarian aging: Potential mechanism and protective strategies

Ovarian aging occurs approximately 10 years prior to the natural age-associated functional decline of other organ systems. With the increase of life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Therefore, understanding the causes and molecular mechanisms of ovarian aging is very essential for the inhibition of age-related diseases and the promotion of health and longevity in women. Recently, studies have revealed an association between adipose tissue (AT) and ovarian aging. Alterations in the function and quantity of AT have profound consequences on ovarian function because AT is central for follicular development, lipid metabolism, and hormonal regulation. Moreover, the interplay between AT and the ovary is bidirectional, with ovary-derived signals directly affecting AT biology. In this review, we summarize the current knowledge of the complex molecular mechanisms controlling the crosstalk between the AT and ovarian aging, and further discuss how therapeutic targeting of the AT can delay ovarian aging.

Analysis of changes in the proteomic profile of porcine corpus luteum during different stages of the oestrous cycle: effects of PPAR gamma ligands

CONTEXT

The corpus luteum (CL) is an endocrine gland in the ovary of mature females during the oestrous cycle and pregnancy. There is evidence of a relationship between the secretory function of the CL and PPARs.

AIMS

In this study, we investigated the changes in the proteome of the CL in relation to the phase of the oestrous cycle and the impact of PPARγ ligands on the proteomic profile of the CL during the mid- and late-luteal phase of the oestrous cycle.

METHODS

The porcine CL explants were incubated in vitro for 6h in the presence of PPARγ ligands (agonist pioglitazone, antagonist T0070907) or without ligands. Global proteomic analysis was performed using the TMT-based LC-MS/MS method.

KEY RESULTS

The obtained results showed the disparity in proteomic profile of the untreated CL - different abundance of 23 and 28 proteins for the mid- and late-luteal phase, respectively. Moreover, seven proteins were differentially regulated in the CL tissue treated with PPARγ ligands. In the mid-luteal phase, one protein, CAND1, was downregulated after treatment with T0070907. In the late-luteal phase, the proteins SPTAN1, GOLGB1, TP53BP1, MATR3, RRBP1 and SRRT were upregulated by pioglitazone.

CONCLUSIONS

Comparative proteomic analysis revealed that certain proteins constitute a specific proteomic signature for each examined phase. Moreover, the study showed that the effect of PPARγ ligands on the CL proteome was rather limited.

IMPLICATIONS

The results provide a broader insight into the processes that may be responsible for the structural luteolysis of the porcine CL, in addition to apoptosis and autophagy.

The Role of Peroxisome Proliferator-Activated Receptors in PGF2α-Induced Luteolysis in the Bovine Corpus Luteum

Simple Summary

The corpus luteum (CL) is responsible for progesterone (P₄) secretion. In the absence of pregnancy, luteolysis occurs, which leads to a reduction in P₄ production, followed by the structural regression of the CL. In cows, prostaglandin F_2α (PGF_2α) is the main luteolytic factor. It is also an endogenous ligand for peroxisome proliferator-activated receptors (PPARs), which are important factors regulating mammalian reproductive function. However, the mechanisms of action of PPAR isoforms, i.e., PPARα, PPARδ and PPARγ, in the luteolytic pathways in cattle are still not fully understood. The aim of this in vitro study was to determine the expression of PPAR isoforms in the bovine CL throughout the estrous cycle, and their involvement in PGF_2α-induced processes related to luteolysis. The obtained results indicate that the expression of PPARs changes in the bovine CL throughout the estrous cycle; moreover, PGF_2α affects its expression. This study provides evidence that PPARγ, among all examined PPAR isoforms, could be involved in the regulation of PGF_2α-induced luteolysis in cattle, and PPARs may affect CL regression at multiple sites. These results help to widen the knowledge of the mechanisms of luteal regression in the bovine CL.

Abstract

The participation of peroxisome proliferator-activated receptors (PPARs) in ovarian function in cattle is still not fully understood. The aim of this in vitro study was to determine: (i) the immunolocalization, mRNA expression and tissue concentration of PPARα, PPARδ and PPARγ in the bovine corpus luteum (CL) (n = 40) throughout the estrous cycle, and (ii) the involvement of PPAR in PGF_2α-induced processes related to luteolysis. CL (n = 9) explants were cultured in the presence of PPAR antagonists (10⁻⁵ M) in combination with or without PGF_2α receptor antagonist (10⁻⁵ M) and PGF_2α (10⁻⁶ M). The mRNA and protein expression of PPARs was evaluated through qPCR, IHC, and ELISA, respectively. The results showed that PPAR mRNA and protein expression differed according to the luteal stages. PGF_2α upregulated PPARδ and PPARγ mRNA expression in the bovine CL in vitro, whereas PPARγ increased the inhibitory effect of PGF_2α by decreasing progesterone secretion and the mRNA expression of hydroxy-delta-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 1 (HSD3B1) in the CL explants; mRNA transcription of tumor necrosis factor α (TNFα) and inducible nitric oxide synthase (iNOS) was increased. The obtained results indicate that the mRNA and protein expression of PPARs changes in the bovine CL throughout the estrous cycle and under the influence of PGF_2α. We suggest that isoform γ, among all examined PPARs, could be a factor involved in the regulation of PGF_2α-induced processes related to luteolysis in the bovine CL. Further studies are needed to understand the role of PPAR in luteal regression in the CL of cattle.

Phthalate monoesters act through peroxisome proliferator-activated receptors in the mouse ovary

Widespread use of phthalates as solvents and plasticizers leads to everyday human exposure. The mechanisms by which phthalate metabolites act as ovarian toxicants are not fully understood. Thus, this study tested the hypothesis that the phthalate metabolites monononyl phthalate (MNP), monoisononyl phthalate (MiNP), mono(2-ethylhexyl) phthalate (MEHP), monobenzyl phthalate (MBzP), monobutyl phthalate (MBP), monoisobutyl phthalate (MiBP), and monoethyl phthalate (MEP) act through peroxisome proliferator-activated receptors (PPARs) in mouse granulosa cells. Primary granulosa cells were isolated from CD-1 mice and cultured with vehicle control (dimethyl sulfoxide) or MNP, MiNP, MEHP, MBzP, MBP, MiBP, or MEP (0.4-400 μM) for 24 h. Following culture, qPCR was performed for known PPAR targets, Fabp4 and Cd36. Treatment with the phthalate metabolites led to significant changes in Fabp4 and Cd36 expression relative to control in dose-dependent or nonmonotonic fashion. Primary granulosa cell cultures were also transfected with a DNA plasmid containing luciferase expressed under the control of a consensus PPAR response element. MNP, MiNP, MEHP, and MBzP caused dose-dependent changes in expression of luciferase, indicating the presence of functional endogenous PPAR receptors in the granulosa cells that respond to phthalate metabolites. The effects of phthalate metabolites on PPAR target genes were inhibited in most of the cultures by co-treatment with the PPAR-γ inhibitor, T0070907, or with the PPAR-α inhibitor, GW6471. Collectively, these data suggest that some phthalate metabolites may act through endogenous PPAR nuclear receptors in the ovary and that the differing structures of the phthalates result in different levels of activity.

Follicular Fluid: A Powerful Tool for the Understanding and Diagnosis of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) represents one of the leading causes of anovulatory infertility and affects 5% to 20% of women worldwide. Until today, both the subsequent etiology and pathophysiology of PCOS remain unclear, and patients with PCOS that undergo assisted reproductive techniques (ART) might present a poor to exaggerated response, low oocyte quality, ovarian hyperstimulation syndrome, as well as changes in the follicular fluid metabolites pattern. These abnormalities originate a decrease of Metaphase II (MII) oocytes and decreased rates for fertilization, cleavage, implantation, blastocyst conversion, poor egg to follicle ratio, and increased miscarriages. Focus on obtaining high-quality embryos has been taken into more consideration over the years. Nowadays, the use of metabolomic analysis in the quantification of proteins and peptides in biological matrices might predict, with more accuracy, the success in assisted reproductive technology. In this article, we review the use of human follicular fluid as the matrix in metabolomic analysis for diagnostic and ART predictor of success for PCOS patients.

Lipid metabolism and endometrial receptivity

BACKGROUND

Obesity has now been recognized as a high-risk factor for reproductive health. Although remarkable advancements have been made in ART, a considerable number of infertile obese women still suffer from serial implantation failure, despite the high quality of embryos transferred. Although obesity has long been known to exert various deleterious effects on female fertility, the underlying mechanisms, especially the roles of lipid metabolism in endometrial receptivity, remain largely elusive.

OBJECTIVE AND RATIONALE

This review summarizes current evidence on the impacts of several major lipids and lipid-derived mediators on the embryonic implantation process. Emerging methods for evaluating endometrial receptivity, for example transcriptomic and lipidomic analysis, are also discussed.

SEARCH METHODS

The PubMed and Embase databases were searched using the following keywords: (lipid or fatty acid or prostaglandin or phospholipid or sphingolipid or endocannabinoid or lysophosphatidic acid or cholesterol or progesterone or estrogen or transcriptomic or lipidomic or obesity or dyslipidemia or polycystic ovary syndrome) AND (endometrial receptivity or uterine receptivity or embryo implantation or assisted reproductive technology or in vitro fertilization or embryo transfer). A comprehensive literature search was performed on the roles of lipid-related metabolic pathways in embryo implantation published between January 1970 and March 2022. Only studies with original data and reviews published in English were included in this review. Additional information was obtained from references cited in the articles resulting from the literature search.

OUTCOMES

Recent studies have shown that a fatty acids-related pro-inflammatory response in the embryo-endometrium boundary facilitates pregnancy via mediation of prostaglandin signaling. Phospholipid-derived mediators, for example endocannabinoids, lysophosphatidic acid and sphingosine-1-phosphate, are associated with endometrial receptivity, embryo spacing and decidualization based on evidence from both animal and human studies. Progesterone and estrogen are two cholesterol-derived steroid hormones that synergistically mediate the structural and functional alterations in the uterus ready for blastocyst implantation. Variations in serum cholesterol profiles throughout the menstrual cycle imply a demand for steroidogenesis at the time of window of implantation (WOI). Since 2002, endometrial transcriptomic analysis has been serving as a diagnostic tool for WOI dating. Numerous genes that govern lipid homeostasis have been identified and, based on specific alterations of lipidomic signatures differentially expressed in WOI, lipidomic analysis of endometrial fluid provides a possibility for non-invasive diagnosis of lipids alterations during the WOI.

WIDER IMPLICATIONS

Given that lipid metabolic dysregulation potentially plays a role in infertility, a better understanding of lipid metabolism could have significant clinical implications for the diagnosis and treatment of female reproductive disorders.

The effects of polycyclic aromatic compounds (PACs) on mammalian ovarian function

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Toxicity of polycyclic aromatic compounds (PACs) is limited to a subset of PACs.

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Exposure to these compounds impact major processes necessary for ovarian function.

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PAC exposure causes follicle loss and aberrant steroid production and angiogenesis.

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PAC exposure may increase the risk for impaired fertility and ovarian pathologies.

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The study of PACs as ovarian toxicants should include additional compounds.

Polycyclic aromatic compounds (PACs) are a broad class of contaminants ubiquitously present in the environment due to natural and anthropogenic activities. With increasing industrialization and reliance on petroleum worldwide, PACs are increasingly being detected in different environmental compartments. Previous studies have shown that PACs possess endocrine disruptive properties as these compounds often interfere with hormone signaling and function. In females, the ovary is largely responsible for regulating reproductive and endocrine function and thus, serves as a primary target for PAC-mediated toxicity. Perturbations in the signaling pathways that mediate ovarian folliculogenesis, steroidogenesis and angiogenesis can lead to adverse reproductive outcomes including polycystic ovary syndrome, premature ovarian insufficiency, and infertility. To date, the impact of PACs on ovarian function has focused predominantly on polycyclic aromatic hydrocarbons like benzo(a)pyrene, 3-methylcholanthrene and 7,12-dimethylbenz[a]anthracene. However, investigation into the impact of substituted PACs including halogenated, heterocyclic, and alkylated PACs on mammalian reproduction has been largely overlooked despite the fact that these compounds are found in higher abundance in free-ranging wildlife. This review aims to discuss current literature on the effects of PACs on the ovary in mammals, with a particular focus on folliculogenesis, steroidogenesis and angiogenesis, which are key processes necessary for proper ovarian functions.

Effects of endocrine disrupting chemicals on gonad development: Mechanistic insights from fish and mammals

Over the past century, evidence has emerged that endocrine disrupting chemicals (EDCs) have an impact on reproductive health. An increased frequency of reproductive disorders has been observed worldwide in both wildlife and humans that is correlated with accidental exposures to EDCs and their increased production. Epidemiological and experimental studies have highlighted the consequences of early exposures and the existence of key windows of sensitivity during development. Such early in life exposures can have an immediate impact on gonadal and reproductive tract development, as well as on long-term reproductive health in both males and females. Traditionally, EDCs were thought to exert their effects by modifying the endocrine pathways controlling reproduction. Advances in knowledge of the mechanisms regulating sex determination, differentiation and gonadal development in fish and rodents have led to a better understanding of the molecular mechanisms underlying the effects of early exposure to EDCs on reproduction. In this manuscript, we review the key developmental stages sensitive to EDCs and the state of knowledge on the mechanisms by which model EDCs affect these processes, based on the roadmap of gonad development specific to fish and mammals.

The Key Role of Peroxisomes in Follicular Growth, Oocyte Maturation, Ovulation, and Steroid Biosynthesis

The absence of peroxisomes can cause disease in the human reproductive system, including the ovaries. The available peroxisomal gene-knockout female mouse models, which exhibit pathological changes in the ovary and reduced fertility, are listed in this review. Our review article provides the first systematic presentation of peroxisomal regulation and its possible functions in the ovary. Our immunofluorescence results reveal that peroxisomes are present in all cell types in the ovary; however, peroxisomes exhibit different numerical abundances and strong heterogeneity in their protein composition among distinct ovarian cell types. The peroxisomal compartment is strongly altered during follicular development and during oocyte maturation, which suggests that peroxisomes play protective roles in oocytes against oxidative stress and lipotoxicity during ovulation and in the survival of oocytes before conception. In addition, the peroxisomal compartment is involved in steroid synthesis, and peroxisomal dysfunction leads to disorder in the sexual hormone production process. However, an understanding of the cellular and molecular mechanisms underlying these physiological and pathological processes is lacking. To date, no effective treatment for peroxisome-related disease has been developed, and only supportive methods are available. Thus, further investigation is needed to resolve peroxisome deficiency in the ovary and eventually promote female fertility.

Selective loss of kisspeptin signaling in oocytes causes progressive premature ovulatory failure

STUDY QUESTION

Does direct kisspeptin signaling in the oocyte have a role in the control of follicular dynamics and ovulation?

SUMMARY ANSWER

Kisspeptin signaling in the oocyte plays a relevant physiological role in the direct control of ovulation; oocyte-specific ablation of kisspeptin receptor, Gpr54, induces a state of premature ovulatory failure in mice that recapitulates some features of premature ovarian insufficiency (POI).

WHAT IS KNOWN ALREADY

Kisspeptins, encoded by the Kiss1 gene, are essential for the control of ovulation and fertility, acting primarily on hypothalamic GnRH neurons to stimulate gonadotropin secretion. However, kisspeptins and their receptor, Gpr54, are also expressed in the ovary of different mammalian species, including humans, where their physiological roles remain contentious and poorly characterized.

STUDY DESIGN, SIZE, DURATION

A novel mouse line with conditional ablation of Gpr54 in oocytes, named OoGpr54^−/−, was generated and studied in terms of follicular and ovulatory dynamics at different age-points of postnatal maturation. A total of 59 OoGpr54^−/− mice and 47 corresponding controls were analyzed. In addition, direct RNA sequencing was applied to ovarian samples from 8 OoGpr54^−/− and 7 control mice at 6 months of age, and gonadotropin priming for ovulatory induction was conducted in mice (N = 7) from both genotypes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Oocyte-selective ablation of Gpr54 in the oocyte was achieved in vivo by crossing a Gdf9-driven Cre-expressing transgenic mouse line with a Gpr54 LoxP mouse line. The resulting OoGpr54^−/− mouse line was subjected to phenotypic, histological, hormonal and molecular analyses at different age-points of postnatal maturation (Day 45, and 2, 4, 6 and 10–11 months of age), in order to characterize the timing of puberty, ovarian follicular dynamics and ovulation, with particular attention to identification of features reminiscent of POI. The molecular signature of ovaries from OoGpr54^−/− mice was defined by direct RNA sequencing. Ovulatory responses to gonadotropin priming were also assessed in OoGpr54^−/− mice.

MAIN RESULTS AND THE ROLE OF CHANCE

Oocyte-specific ablation of Gpr54 caused premature ovulatory failure, with some POI-like features. OoGpr54^−/− mice had preserved puberty onset, without signs of hypogonadism. However, already at 2 months of age, 40% of OoGpr54^−/− females showed histological features reminiscent of ovarian failure and anovulation. Penetrance of the phenotype progressed with age, with >80% and 100% of OoGpr54^−/− females displaying complete ovulatory failure by 6- and 10 months, respectively. This occurred despite unaltered hypothalamic Gpr54 expression and gonadotropin levels. Yet, OoGpr54^−/− mice had decreased sex steroid levels. While the RNA signature of OoGpr54^−/− ovaries was dominated by the anovulatory state, oocyte-specific ablation of Gpr54 significantly up- or downregulated of a set of 21 genes, including those encoding pituitary adenylate cyclase-activating polypeptide, Wnt-10B, matrix-metalloprotease-12, vitamin A-related factors and calcium-activated chloride channel-2, which might contribute to the POI-like state. Notably, the anovulatory state of young OoGpr54^−/− mice could be rescued by gonadotropin priming.

LARGE SCALE DATA

N/A. 

LIMITATIONS, REASONS FOR CAUTION

Conditional ablation of Gpr54 in oocytes unambiguously caused premature ovulatory failure in mice; yet, the ultimate molecular mechanisms for such state of POI can be only inferred on the basis of RNAseq data and need further elucidation, since some of the molecular changes observed in OoGpr54^−/− ovaries were secondary to the anovulatory state. Direct translation of mouse findings to human disease should be made with caution since, despite the conserved expression of Kiss1/kisspeptin and Gpr54 in rodents and humans, our mouse model does not recapitulate all features of common forms of POI.

WIDER IMPLICATIONS OF THE FINDINGS

Deregulation of kisspeptin signaling in the oocyte might be an underlying, and previously unnoticed, cause for some forms of POI in women.

STUDY FUNDING/COMPETING INTEREST(S)

This work was primarily supported by a grant to M.P. and M.T.-S. from the FiDiPro (Finnish Distinguished Professor) Program of the Academy of Finland. Additional financial support came from grant BFU2017-83934-P (M.T.-S.; Ministerio de Economía y Competitividad, Spain; co-funded with EU funds/FEDER Program), research funds from the IVIRMA International Award in Reproductive Medicine (M.T.-S.), and EFSD Albert Renold Fellowship Programme (S.T.R.). The authors have no conflicts of interest to declare in relation to the contents of this work.

TRIAL REGISTRATION NUMBER

N/A.

Systematic Understanding of Anti-Aging Effect of Coenzyme Q10 on Oocyte Through a Network Pharmacology Approach

BACKGROUND

Maternal oocyte aging is strongly contributing to age-related decline in female fertility. Coenzyme Q10 (CoQ10) exerts positive effects in improving aging-related deterioration of oocyte quality, but the exact mechanism is unclear.

OBJECTIVE

To reveal the system-level mechanism of CoQ10's anti-aging effect on oocytes based on network pharmacology.

METHODS

This study adopted a systems network pharmacology approach, including target identification, data integration, network and module construction, bioinformatics analysis, molecular docking, and molecular dynamics simulation.

RESULT

A total of 27 potential therapeutic targets were screened out. Seven hub targets (PPARA, CAT, MAPK14, SQSTM1, HMOX1, GRB2, and GSR) were identified. Functional and pathway enrichment analysis indicated that these 27 putative targets exerted therapeutic effects on oocyte aging by regulating signaling pathways (e.g., PPAR, TNF, apoptosis, necroptosisn, prolactin, and MAPK signaling pathway), and are involved oxidation-reduction process, mitochondrion, enzyme binding, reactive oxygen species metabolic process, ATP binding, among others. In addition, five densely linked functional modules revealed the potential mechanisms of CoQ10 in improving aging-related deterioration of oocyte quality are closely related to antioxidant, mitochondrial function enhancement, autophagy, anti-apoptosis, and immune and endocrine system regulation. The molecular docking study reveals that seven hub targets have a good binding affinity towards CoQ10, and molecular dynamics simulation confirms the stability of the interaction between the hub targets and the CoQ10 ligand.

CONCLUSION

This network pharmacology study revealed the multiple mechanisms involved in the anti-aging effect of CoQ10 on oocytes. The molecular docking and molecular dynamics simulation provide evidence that CoQ10 may act on these hub targets to fight against oocytes aging.

Metabolic exchanges between the oocyte and its environment: focus on lipids

Finely regulated fatty acid (FA) metabolism within ovarian follicles is crucial to follicular development and influences the quality of the enclosed oocyte, which relies on the surrounding intra-follicular environment for its growth and maturation. A growing number of studies have examined the association between the lipid composition of follicular compartments and oocyte quality. In this review, we focus on lipids, their possible exchanges between compartments within the ovarian follicle and their involvement in different pathways during oocyte final growth and maturation. Lipidomics provides a detailed snapshot of the global lipid profiles and identified lipids, clearly discriminating the cells or fluid from follicles at distinct physiological stages. Follicular fluid appears as a main mediator of lipid exchanges between follicular somatic cells and the oocyte, through vesicle-mediated and non-vesicular transport of esterified and free FA. A variety of expression data allowed the identification of common and cell-type-specific actors of lipid metabolism in theca cells, granulosa cells, cumulus cells and oocytes, including key regulators of FA uptake, FA transport, lipid transformation, lipoprotein synthesis and protein palmitoylation. They act in harmony to accompany follicular development, and maintain intra-follicular homeostasis to allow the oocyte to accumulate energy and membrane lipids for subsequent meiotic divisions and first embryo cleavages.

The therapeutic potential of inhibiting PPARγ phosphorylation to treat type 2 diabetes

A promising approach for treating type 2 diabetes mellitus (T2DM) is to target the Peroxisome Proliferator-Activated Receptor γ (PPARγ) transcription factor, which regulates the expression of proteins critical for T2DM. Mechanisms involved in PPARγ signaling are poorly understood, yet globally increasing T2DM prevalence demands improvements in drug design. Synthetic, nonactivating PPARγ ligands can abolish the phosphorylation of PPARγ at Ser273, a posttranslational modification correlated with obesity and insulin resistance. It is not understood how these ligands prevent phosphorylation, and the lack of experimental mechanistic information can be attributed to previous ambiguity in the field as well as to limitations in experimental approaches; in silico modeling currently provides the only insight into how ligands block Ser273 phosphorylation. The future availability of experimental evidence is critical for clarifying the mechanism by which ligands prevent phosphorylation and should be the priority of future T2DM-focused research. Following this, the properties of ligands that enable them to block phosphorylation can be improved upon to generate ligands tailored for blocking phosphorylation and therefore restoring insulin sensitivity. This would represent a significant step forward for treating T2DM. This review summarizes current knowledge of the roles of PPARγ in T2DM as well as the effects of synthetic ligands on the modulation of these roles. We hypothesize potential factors that contribute to the reduction in recent developments and summarize what has currently been done to shed light on this critical field of research.

In Utero and Lactational Exposure to Flame Retardants Disrupts Rat Ovarian Follicular Development and Advances Puberty

Brominated flame retardants (BFRs), including polybrominated diphenyl ethers and hexabromocyclododecane, leach out from consumer products into the environment. Exposure to BFRs has been associated with effects on endocrine homeostasis. To test the hypothesis that in utero and lactational exposure to BFRs may affect the reproductive system of female offspring, adult female Sprague Dawley rats were fed diets formulated to deliver nominal doses (0, 0.06, 20, or 60 mg/kg/day) of a BFR dietary mixture mimicking the relative congener levels in house dust from prior to mating until weaning. Vaginal opening and the day of first estrus occurred at a significantly earlier age among offspring from the 20 mg/kg/day BFR group, indicating that the onset of puberty was advanced. Histological analysis of ovaries from postnatal day 46 offspring revealed an increase in the incidence of abnormal follicles. A toxicogenomic analysis of ovarian gene expression identified upstream regulators, including HIF1A, CREB1, EGF, the β-estradiol, and PPARA pathways, predicted to be downregulated in the 20 or 60 mg/kg/day group and to contribute to the gene expression patterns observed. Thus, perinatal exposure to BFRs dysregulated ovarian folliculogenesis and signaling pathways that are fundamental for ovarian function in the adult.

Ovarian Toxicity and Epigenetic Mechanisms of Phthalates and Their Metabolites

Ovary plays an important role in the female reproductive system. The maintenance and regulation of ovarian function are affected by various physical and chemical factors. With the development of industrialization, environmental pollutants have caused great harm to public health. Phthalates, as a class of endocrine-disrupting chemicals (EDCs), are synthesized and used in large quantities as plasticizers due to their chemical properties. They are easily released into environment because of their noncovalent interactions with substances, causing human exposure and possibly impairing ovary. In recent years, more and more attention has been paid to the role of epigenetics in the occurrence and development of diseases. And it is urgent to study the role of methylation, gene imprinting, miRNA, and other epigenetic mechanisms in reproductive toxicology.

A novel PPRC1 point mutation in a Chinese family with premature ovarian failure: A case study

BACKGROUND

Patients with premature ovarian failure (POF) have an at least 6-month history of amenorrhea and elevated follicle-stimulating hormone levels in plasma. Most of the POF causes are idiopathic and hereditary, and chromosomal abnormalities have been associated with POF development. A pedigree study was performed on a family with idiopathic POF to observe the possible link between gene mutation and POF development.

METHODS

In total, eight women were diagnosed with POF and seven POF patients and five non-POF members from the same family were evaluated by whole exome sequencing and Sanger sequencing. An apoptotic assay, senescence staining, real-time polymerase chain reaction (qPCR) and overexpression of the peroxisome proliferator-activated receptor gamma coactivator-related 1 (PPRC1) gene were performed to examine the association of POF in vitro.

RESULTS

Through whole exome sequencing and Sanger sequencing, a novel point mutation (NM_015062: c.2902C>T:p.Thr958Ile) was identified and verified in the PPRC1 gene on chromosome 10 (10q24.32). The point mutation only presented in all the seven POF cases and not in non-POF cases or public databases. Subsequent expression of PPRC1 in COV434 granulosa cells showed that PPRC1 might be involved in regulating granulosa cell apoptosis but not senescence-associated POF development.

CONCLUSIONS

A novel point mutation in the PPRC1 gene was identified by the pedigree study and by sequence analysis of the case series with idiopathic POF in the present study. The subsequent PPRC1 expression analysis showed that PPRC1 was not involved in senescence-associated POF development. Further studies will be needed to confirm the link between PPRC1 gene mutation and POF.

Expression of tissue factor and tissue factor pathway inhibitors during ovulation in rats: a relevance to the ovarian hyperstimulation syndrome

BACKGROUND

Blood coagulation has been associated with ovulation and female infertility. In this study, the expression of the tissue factor system was examined during ovulation in immature rats; the correlation between tissue factor and ovarian hyperstimulation syndrome (OHSS) was evaluated both in rats and human follicular fluids.

METHODS

Ovaries were obtained at various times after human chorionic gonadotropin (hCG) injection to investigate the expression of tissue factor system. Expression levels of ovarian tissue factor, tissue factor pathway inhibitor (Tfpi)-1 and Tfpi-2 genes and proteins were determined by real-time quantitative polymerase chain reaction (qPCR), and Western blot and immunofluorescence analyses, respectively. Expression levels of tissue factor system were also investigated in ovaries of OHSS-induced rats and in follicular fluid of infertile women.

RESULTS

The expression of tissue factor in the preovulatory follicles was stimulated by hCG, reaching a maximum at 6 h. Tissue factor was expressed in the oocytes and the preovulatory follicles. Tfpi-2 mRNA levels were mainly increased by hCG in the granulosa cells whereas the mRNA levels of Tfpi-1 were decreased by hCG. Human CG-stimulated tissue factor expression was inhibited by the progesterone receptor antagonist. The increase in Tfpi-2 expression by hCG was decreased by the proliferator-activated receptor γ (PPARγ) antagonist. Decreased expression of the tissue factor was detected in OHSS-induced rats. Interestingly, the tissue factor concentrations in the follicular fluids of women undergoing in vitro fertilization were correlated with pregnancy but not with OHSS.

CONCLUSIONS

Collectively, the results indicate that tissue factor and Tfpi-2 expression is stimulated during the ovulatory process in rats; moreover, a correlation exists between the levels of tissue factor and OHSS in rats but not in humans.

Wnt/β-catenin Pathway-Mediated PPARδ Expression during Embryonic Development Differentiation and Disease

The Wnt/β-catenin signaling pathway plays a crucial role in early embryonic development. Wnt/β-catenin signaling is a major regulator of cell proliferation and keeps embryonic stem cells (ESCs) in the pluripotent state. Dysregulation of Wnt signaling in the early developmental stages causes several hereditary diseases that lead to embryonic abnormalities. Several other signaling molecules are directly or indirectly activated in response to Wnt/β-catenin stimulation. The crosstalk of these signaling factors either synergizes or opposes the transcriptional activation of β-catenin/Tcf4-mediated target gene expression. Recently, the crosstalk between the peroxisome proliferator-activated receptor delta (PPARδ), which belongs to the steroid superfamily, and Wnt/β-catenin signaling has been reported to take place during several aspects of embryonic development. However, numerous questions need to be answered regarding the function and regulation of PPARδ in coordination with the Wnt/β-catenin pathway. Here, we have summarized the functional activation of the PPARδ in co-ordination with the Wnt/β-catenin pathway during the regulation of several aspects of embryonic development, stem cell regulation and maintenance, as well as during the progression of several metabolic disorders.

Current Knowledge on the Multifactorial Regulation of Corpora Lutea Lifespan: The Rabbit Model

Simple Summary

Corpora lutea (CL) are temporary endocrine structures that secrete progesterone, which is essential for maintaining a healthy pregnancy. A variety of regulatory factors come into play in modulating the functional lifespan of CL, with luteotropic and luteolytic effects. Many aspects of luteal phase physiology have been clarified, yet many others have not yet been determined, including the molecular and/or cellular mechanisms that maintain the CL from the beginning of luteolysis during early CL development. This paper summarizes our current knowledge of the endocrine and cellular mechanisms involved in multifactorial CL lifespan regulation, using the pseudopregnant rabbit model.

Abstract

Our research group studied the biological regulatory mechanisms of the corpora lutea (CL), paying particular attention to the pseudopregnant rabbit model, which has the advantage that the relative luteal age following ovulation is induced by the gonadotrophin-releasing hormone (GnRH). CL are temporary endocrine structures that secrete progesterone, which is essential for maintaining a healthy pregnancy. It is now clear that, besides the classical regulatory mechanism exerted by prostaglandin E2 (luteotropic) and prostaglandin F2α (luteolytic), a considerable number of other effectors assist in the regulation of CL. The aim of this paper is to summarize our current knowledge of the multifactorial mechanisms regulating CL lifespan in rabbits. Given the essential role of CL in reproductive success, a deeper understanding of the regulatory mechanisms will provide us with valuable insights on various reproductive issues that hinder fertility in this and other mammalian species, allowing to overcome the challenges for new and more efficient breeding strategies.

Molecular Targets and Associated Signaling Pathways of Jingshu Granules in Ovarian Cysts Based on Systemic Pharmacological Analysis

Background

More than a third of women could develop ovarian cysts during their lifetime. Jingshu granules are used for the treatment of gynecological disease of primary dysmenorrhea. However, the molecular mechanisms of Jingshu granules in ovarian cysts are still unreported. We aimed to find the active ingredients, molecular targets, and potential signaling pathways of Jingshu granules in ovarian cysts by using the systemic pharmacological analysis.

Methods

Firstly, the effect of Jingshu granules on female hormones and reproductive organs of young female rats was evaluated. Secondly, candidate pharmaceutical ingredients of Jingshu granules were retrieved from the traditional Chinese medicine systems pharmacology (TCMSP) database and analysis platform. Potential protein targets for the active ingredients in Jingshu granules were then identified according to the oral bioavailability and drug-likeness indices. Thirdly, ovarian cyst-related gene targets were screened based on different databases. Finally, enrichment analysis was used to analyze the potential biological function of intersection targets between Jingshu granules and ovarian cysts.

Results

In young female rats, Jingshu granules reduced the secretion of estradiol, progesterone, and prolactin and could affect the development of the uterus. This suggested that Jingshu granules played roles in hormone secretion and reproduction. From the TCMSP, a total of 1021 pharmaceutical ingredients of Jingshu granules were retrieved. After further screening, a total of 166 active ingredients and 159 protein targets of Jingshu granules were identified. In addition, 4488 gene targets of ovarian cysts were screened out. After taking the intersection, a total of 110 intersection targets were identified between potential protein targets of Jingshu granules and gene targets of ovarian cysts. In the functional analysis of 110 intersection targets, 8 signaling pathways including progesterone-mediated oocyte maturation (MAPK8 and CDK1 involved), GnRH signaling pathway (JUN involved), T cell receptor signaling pathway and Toll-like receptor signaling pathway (MAPK1 involved), NOD-like receptor signaling pathway (TNF, IL6, and IL1B involved), p53 signaling pathway (CDK2 and CDK4 involved), VEGF signaling pathway (MAPK14 involved), and PPAR signaling pathway (PPARG involved) were obtained.

Conclusion

Our study revealed that Jingshu granules could function in patients with ovarian cysts through a number of molecular targets and signaling pathways. Our study may provide a new field into the mechanisms of Jingshu granules in ovarian cysts, from the molecular to the signaling pathway level.

The myokine irisin: localization and effects in swine late medium and large antral ovarian follicle

Irisin is mainly synthesized by skeletal muscle tissue, where it is believed to be responsible for the benefits of exercise on metabolism and cardiovascular system. In adipose tissue, its best-known effect is the browning of white adipocytes, resulting in the increase of thermogenesis and energy expenditure. As it has been largely documented that metabolic dysfunctions can frequently be associated with reductions in fertility, the possible involvement of this molecule in the regulation of reproductive processes represents an issue to be addressed. On this basis, the first aim of this work was the evaluation of the presence of irisin in the swine ovary; then, we investigated the expression of the associated molecules FNDC5, PGC-1α, and PPAR-γ. To verify a potential modulatory role both on ovarian function and on redox status, cell growth, steroidogenesis, production of superoxide anion and nitric oxide, the nonenzymatic antioxidant scavengers, were assessed in vitro on granulosa cells treated with increasing concentrations of irisin (50, 100, and 150 ng/mL). The data collected demonstrate the presence of irisin in swine ovarian follicle. Moreover, the highest concentrations tested stimulated metabolic activity and inhibited cell proliferation (P < 0.05); the peptide exerted a biphasic effect on progesterone (P < 0.01) production and, at the highest concentrations, inhibited nitric oxide while stimulated the nonenzymatic antioxidant power (P < 0.05). Superoxide anion and estradiol 17β were unaffected. The demonstration of the local presence of irisin at the ovarian level and the highlighted effects allow us to qualify this molecule as a potential physiological regulator of follicular function.

[Role of leptin and nuclear receptor PPARγ in PCOS pathogenesis]

Polycystic ovary syndrome (PCOS) is the most common cause of female endocrine infertility. Insulin resistanсе is supposed to be one of the essential factors of this disease pathways. At the same time, the mechanisms of PCOS development in insulin-resistant patients have not been completely established. Leptin and Peroxisome Proliferator-Activated Receptor γ(PPARγ) are involved in carbohydrate metabolism and reproduction function regulation. It indicates that leptin and PPARγ possibly play a role in the pathways of PCOS. This article is a review of publications on this issue. The purpose of this review was to systematize the available information on the molecular mechanisms that determine the role of leptin and PPARγ in the development of PCOS. The literature search was carried out from 04/05/2020 to 05/17/2020 using the scientific literature databases: NCBI PubMed (foreign sources) and Cyberleninka (domestic sources). We analyzed publications for the period 1990-2020.The review presents the current understanding of the possible role of leptin and PPARγ in the regulation of endocrine, immune systems, and reproductive function, as well as in the development of PCOS. Currently, no studies cover the mechanisms of interaction between leptin and PPARγ in the pathways of this syndrome. The available studies indicating the individual contribution and association of leptin and PPARγ with PCOS are conflicting and have many limitations. Therefore, more studies of direct and indirect interaction of leptin and PPARγ, as well as their role in PCOS pathways, are needed.

Etiopathogenesis, Challenges and Remedies Associated With Female Genital Tuberculosis: Potential Role of Nuclear Receptors

Extra-pulmonary tuberculosis (EPTB) is recognized mainly as a secondary manifestation of a primary tuberculosis (TB) infection in the lungs contributing to a high incidence of morbidity and mortality. The TB bacilli upon reactivation maneuver from the primary site disseminating to other organs. Diagnosis and treatment of EPTB remains challenging due to the abstruse positioning of the infected organs and the associated invasiveness of sample acquisition as well as misdiagnosis, associated comorbidities, and the inadequacy of biomarkers. Female genital tuberculosis (FGTB) represents the most perilous form of EPTB leading to poor uterine receptivity (UR), recurrent implantation failure and infertility in females. Although the number of TB cases is reducing, FGTB cases are not getting enough attention because of a lack of clinical awareness, nonspecific symptoms, and inappropriate diagnostic measures. This review provides an overview for EPTB, particularly FGTB diagnostics and treatment challenges. We emphasize the need for new therapeutics and highlight the need for the exaction of biomarkers as a point of care diagnostic. Nuclear receptors have reported role in maintaining UR, immune modulation, and TB modulation; therefore, we postulate their role as a therapeutic drug target and biomarker that should be explored in FGTB.

Acute and chronic effects of environmental realistic concentrations of clofibric acid in Danio rerio: Behaviour, oxidative stress, biotransformation and lipid peroxidation endpoints

Due to their widespread use, pharmaceuticals can be metabolized, excreted and ultimately discarded in the environment, thereby affecting aquatic organisms. Lipid-regulating drugs are among the most prescribed medications around the world, controlling human cholesterol levels, in more than 20 million patients. Despite this growing use of lipid-regulating drugs, particularly those whose active metabolite is clofibric acid, the potential toxicological effects of these pharmaceuticals in the environment is not fully characterized. This work intended to characterize the toxicity of an acute (120 hours post-fertilization) and chronic (60 days post-fertilization) exposures to clofibric acid in concentrations of 10.35, 20.7, 41.4, 82.8, and 165.6 μg L^-1 in zebrafish (Danio rerio). The concentrations which were implemented in both exposures were based on predicted environmental concentrations for Portuguese surface waters. The acute effects were analysed focusing on behavioural endpoints (small and large distance travelled, swimming time and total distance travelled), biomarkers of oxidative stress (activity of the enzymes superoxide dismutase, Cu/Zn- and Mn SOD; catalase, CAT; glutathione peroxidase, Se- and total GPx), biotransformation (activity of glutathione S-transferases, GSTs) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Chronically exposed individuals were also histologically analysed for sex determination and gonadal developmental stages. In terms of acute exposure, significant alterations were reported, in terms of behavioural alterations (hypoactivity), followed by an overall increase in all tested biomarkers. Chronically exposed organisms did not show alterations in terms of sex ratio and maturation stages, suggesting that clofibric acid did not act as an endocrine disruptor. Moreover, the metabolism of clofibric acid resulted in increased levels of both forms of SOD activity, especially for animals exposed to higher levels of this drug. An increase of CAT activity was observed in fish exposed to low levels, and a decrease in those exposed to higher amounts of clofibric acid. Both GPx forms had their activities increased. The enzyme of biotransformation GSTs were increased at low levels of clofibric acid but inhibited at higher amounts of this substance. Lipid peroxidation levels were also changed, with an induction of this parameter with increasing amounts of clofibric acid. Changes also occurred in behavioural endpoints and patterns for control organisms and for those exposed to clofibric acid were significantly distinct, for all types (light and darkness) of exposure, and for the two analysed endpoints (small and large distance). Results from this assay allow inferring that clofibric acid can have an ecologically relevant impact in living organisms exposed to this substance, with putative effects on the metabolism of individuals, affecting their behaviour and ultimately their survival.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) and their effects on the ovary

BACKGROUND

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are found widespread in drinking water, foods, food packaging materials and other consumer products. Several PFAS have been identified as endocrine-disrupting chemicals based on their ability to interfere with normal reproductive function and hormonal signalling. Experimental models and epidemiologic studies suggest that PFAS exposures target the ovary and represent major risks for women's health.

OBJECTIVE AND RATIONALE

This review summarises human population and toxicological studies on the association between PFAS exposure and ovarian function.

SEARCH METHODS

A comprehensive review was performed by searching PubMed. Search terms included an extensive list of PFAS and health terms ranging from general keywords (e.g. ovarian, reproductive, follicle, oocyte) to specific keywords (including menarche, menstrual cycle, menopause, primary ovarian insufficiency/premature ovarian failure, steroid hormones), based on the authors' knowledge of the topic and key terms.

OUTCOMES

Clinical evidence demonstrates the presence of PFAS in follicular fluid and their ability to pass through the blood-follicle barrier. Although some studies found no evidence associating PFAS exposure with disruption in ovarian function, numerous epidemiologic studies, mostly with cross-sectional study designs, have identified associations of higher PFAS exposure with later menarche, irregular menstrual cycles, longer cycle length, earlier age of menopause and reduced levels of oestrogens and androgens. Adverse effects of PFAS on ovarian folliculogenesis and steroidogenesis have been confirmed in experimental models. Based on laboratory research findings, PFAS could diminish ovarian reserve and reduce endogenous hormone synthesis through activating peroxisome proliferator-activated receptors, disrupting gap junction intercellular communication between oocyte and granulosa cells, inducing thyroid hormone deficiency, antagonising ovarian enzyme activities involved in ovarian steroidogenesis or inhibiting kisspeptin signalling in the hypothalamus.

WIDER IMPLICATIONS

The published literature supports associations between PFAS exposure and adverse reproductive outcomes; however, the evidence remains insufficient to infer a causal relationship between PFAS exposure and ovarian disorders. Thus, more research is warranted. PFAS are of significant concern because these chemicals are ubiquitous and persistent in the environment and in humans. Moreover, susceptible groups, such as foetuses and pregnant women, may be exposed to harmful combinations of chemicals that include PFAS. However, the role environmental exposures play in reproductive disorders has received little attention by the medical community. To better understand the potential risk of PFAS on human ovarian function, additional experimental studies using PFAS doses equivalent to the exposure levels found in the general human population and mixtures of compounds are required. Prospective investigations in human populations are also warranted to ensure the temporality of PFAS exposure and health endpoints and to minimise the possibility of reverse causality.

Peroxisome proliferator-activated receptor gamma expression along the male genital system and its role in male fertility

Peroxisome proliferator-activated receptor gamma (PPARγ) acts as a ligand activated transcription factor and regulates processes, such as energy homeostasis, cell proliferation and differentiation. PPARγ binds to DNA as a heterodimer with retinoid X receptor and it is activated by polyunsaturated fatty acids and fatty acid derivatives, such as prostaglandins. In addition, the insulin-sensitizing thiazolidinediones, such as rosiglitazone, are potent and specific activators of PPARγ. PPARγ is present along the hypothalamic-pituitary-testis axis and in the testis, where low levels in Leydig cells and higher levels in Sertoli cells as well as in germ cells have been found. High amounts of PPARγ were reported in the normal epididymis and in the prostate, but the receptor was almost undetectable in the seminal vesicles. Interestingly, in the human and in pig, PPARγ protein is highly expressed in ejaculated spermatozoa, suggesting a possible role of PPARγ signaling in the regulation of sperm biology. This implies that both natural and synthetic PPARγ ligands may act directly on sperm improving its performance. Given the close link between energy balance and reproduction, activation of PPARγ may have promising metabolic implications in male reproductive functions. In this review, we first describe PPARγ expression in different compartments of the male reproductive axis. Subsequently, we discuss the role of PPARγ in both physiological and several pathological conditions related to the male fertility.

Differential actions of diacylglycerol acyltransferase (DGAT) 1 and 2 in regulating lipid metabolism and progesterone secretion of goose granulosa cells

Accumulating evidence shows that granulosa cells within both mammalian and avian ovaries have the ability to synthesize fatty acids through de novo lipogenesis and to accumulate triglycerides essential for oocyte and ovarian development. However, very little is known about the exact roles of key genes involved in the lipid metabolic pathway in granulosa cells. The goal of this study was to investigate the differential actions of diacylglycerol acyltransferase (DGAT) 1 and 2, which are recognized as the rate-limiting enzymes catalyzing the last step of triglyceride biosynthesis, in regulating lipid metabolism and steroidogenesis in granulosa cells of goose follicles at different developmental stages. It was observed that the mRNAs encoding DGAT1 and DGAT2 were ubiquitous in all examined granulosa cell layers but exhibited distinct expression profiles during follicle development. Notably, the mRNA levels of DGAT1, DGAT2, FSHR, LHR, STAR, CYP11A1, and 3βHSD remained almost constant in all except for 1-2 follicles within the 8-10 mm cohort, followed by an acute increase/decrease in the F5 follicles. At the cellular level, siRNA-mediated downregulation of DGAT1 or DGAT2 did not change the amount of lipids accumulated in both undifferentiated- and differentiated granulosa cells, while overexpression of DGAT2 promoted lipid accumulation and expression of lipogenic-related genes in these cells. Meanwhile, we found that interfering DGAT2 had no effect but interfering DGAT1 or overexpressing DGAT2 stimulated progesterone secretion in undifferentiated granulosa cells; in contrast, interference or overexpression of DGAT1/2 failed to change progesterone levels in differentiated granulosa cells but differently modulated expression of steroidogenic-related genes. Therefore, it could be concluded that DGAT1 is less efficient than DGAT2 in promoting lipid accumulation in both undifferentiated- and differentiated granulosa cells and that DGAT1 negatively while DGAT2 positively regulates progesterone production in undifferentiated granulosa cells.

What is the impact of PPAR-γ agonist-rosiglitazone on ovarian reserve after hysterectomy? An experimental study

Background/aim

To evaluate the effects of hysterectomy on rat ovaries and the possible protective role of peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist-rosiglitazone against ovarian reserve decrement.

Materials and methods

Forty-five adult Wistar albino rats were randomly divided into three groups. Hysterectomy was performed (n = 15) in group 1 [H]; 1 mg/kg/day PPAR-γ agonist/rosiglitazone was used for 50 days after hysterectomy (n = 15) in group 2 [H + R]; a sham operation was performed (n = 15) in group 3 [control, C]. Blood samples were collected for anti-Müllerian hormone (AMH) evaluation in all groups and simultaneous ovarian Doppler examination was performed in [H] and [H + R] groups before and after (50 days) hysterectomy. All animals were sacrificed to obtain ovaries for histological examination.

Results

AMH levels were found to be significantly decreased at postoperative day 50 in all groups (P < 0.05). Histopathologic analysis showed that primary, preantral, and antral follicle counts were significantly higher in the [H] group as compared to the [C] and [H + R] groups (P < 0.05). There was no significant difference between the [C] and [H + R] groups in terms of follicle numbers (P > 0.05). In the ovarian Doppler blood flow analysis, all parameters were significantly decreased in group [H] (P < 0.05), but not in the [H + R] group (P > 0.05) on postoperative day 50.

Conclusion

Hysterectomy affects the histopathological structure of rat ovaries and PPAR-γ agonist-rosiglitazone improves the ovarian Doppler blood flow parameters.

Iloprost affects in vitro maturation and developmental competence of bovine oocytes

Prostacyclin (PGI2) is synthesised in oviductal fluid and enhance the embryo development during the preimplantation period. The objective of the present study was to determine the effect of an analogue of prostacyclin (iloprost) on the in vitro maturation (IVM) and the developmental competence of bovine oocytes. Cumulus oocyte complexes (COCs) were cultured in maturation medium with iloprost (0.5 μM) for 24 h. We found that iloprost assisted maturation rates and cumulus cell expansion of bovine oocytes, and it increased the mRNA expression of genes related to cumulus expansion: ADAM17, AREG, and TNFAIP6 and cathepsin genes (CTSK and CTSS). Moreover, iloprost reduced the occurrence of apoptosis in COCs and promoted an antiapoptotic balance in the transcription of genes involved in apoptosis (BAX and BCL2). COCs treatment with iloprost during IVM also reduced intracellular reactive oxygen species (ROS) levels, while glutathione (GSH) levels and the mRNA expression of antioxidant genes CAT and GPx4 were markedly increased. We also showed that an analogue of PGI2 influenced the mitochondrial status via distribution rates of mitochondria and mitochondrial membrane potential in oocytes. Although, iloprost-enhanced maturation had no direct effect on number of embryos cleaved, it increased blastocyst rates of bovine embryos as well as proportion of expanded blastocysts. These results indicate that the supplementation of maturation medium with iloprost is beneficial for the maturation efficiency and developmental competence of bovine oocytes.

Peroxisome Proliferator-Activated Receptor Gamma Modulator Promotes Neonatal Mouse Primordial Follicle Activation In Vitro

Peroxisome proliferator-activated receptor gamma (PPARγ) is known as a regulator of cellular functions, including adipogenesis and immune cell activation. The objectives of this study were to investigate the expression of PPARγ and identify the mechanism of primordial follicle activation via PPARγ modulators in mouse ovaries. We first measured the gene expression of PPARγ and determined its relationship with phosphatase and tensin homolog (PTEN), protein kinase B (AKT1), and forkhead box O3a (FOXO3a) expression in neonatal mouse ovaries. We then incubated neonatal mouse ovaries with PPARγ modulators, including rosiglitazone (a synthetic agonist of PPARγ), GW9662 (a synthetic antagonist of PPARγ), and cyclic phosphatidic acid (cPA, a physiological inhibitor of PPARγ), followed by transplantation into adult ovariectomized mice. After the maturation of the transplanted ovaries, primordial follicle growth activation, follicle growth, and embryonic development were evaluated. Finally, the delivery of live pups after embryo transfer into recipient mice was assessed. While PPARγ was expressed in ovaries from mice of all ages, its levels were significantly increased in ovaries from 20-day-old mice. In GW9662-treated ovaries in vitro, PTEN levels were decreased, AKT was activated, and FOXO3a was excluded from the nuclei of primordial follicles. After 1 month, cPA-pretreated, transplanted ovaries produced the highest numbers of oocytes and polar bodies, exhibited the most advanced embryonic development, and had the greatest blastocyst formation rate compared to the rosiglitazone- and GW9662-pretreated groups. Additionally, the successful delivery of live pups after embryo transfer into the recipient mice transplanted with cPA-pretreated ovaries was confirmed. Our study demonstrates that PPARγ participates in primordial follicle activation and development, possibly mediated in part by the PI3K/AKT signaling pathway. Although more studies are required, adapting these findings for the activation of human primordial follicles may lead to treatments for infertility that originates from poor ovarian reserves.