IGF-I signaling is essential for FSH stimulation of AKT and steroidogenic genes in granulosa cells

Genetic advancements and future directions in ruminant livestock breeding: from reference genomes to multiomics innovations

Ruminant livestock provide a rich source of products, such as meat, milk, and wool, and play a critical role in global food security and nutrition. Over the past few decades, genomic studies of ruminant livestock have provided valuable insights into their domestication and the genetic basis of economically important traits, facilitating the breeding of elite varieties. In this review, we summarize the main advancements for domestic ruminants in reference genome assemblies, population genomics, and the identification of functional genes or variants for phenotypic traits. These traits include meat and carcass quality, reproduction, milk production, feed efficiency, wool and cashmere yield, horn development, tail type, coat color, environmental adaptation, and disease resistance. Functional genomic research is entering a new era with the advancements of graphical pangenomics and telomere-to-telomere (T2T) gap-free genome assembly. These advancements promise to improve our understanding of domestication and the molecular mechanisms underlying economically important traits in ruminant livestock. Finally, we provide new perspectives and future directions for genomic research on ruminant genomes. We suggest how ever-increasing multiomics datasets will facilitate future studies and molecular breeding in livestock, including the potential to uncover novel genetic mechanisms underlying phenotypic traits, to enable more accurate genomic prediction models, and to accelerate genetic improvement programs.

Comparative analysis of PI3K-AKT and MEK-ERK1/2 signaling-driven molecular changes in granulosa cells

In brief

PI3K-AKT signaling activates steroidogenesis by inducing estradiol and progesterone production, while MEK-ERK1/2 signaling regulates steroidogenesis by inhibiting estradiol and inducing progesterone production in granulosa cells (GCs). Both pathways are essential for glycolytic and mitochondrial metabolism in these cells.

Abstract

The PI3K-AKT and MEK-ERK1/2 signaling pathways are integral to fundamental cellular processes, such as proliferation, viability and differentiation. In GCs, these pathways are activated by follicle-stimulating hormone (FSH) and IGF1 through respective receptors. We investigated the comparative transcriptome changes induced by the AKT and ERK (ERK1/2) pathways using corresponding inhibitors in GCs. GCs isolated from antral follicles showed positive signals for phospho-AKT and phospho-ERK proteins. Treatment of cultured GCs with FSH and IGF1 induced phospho-AKT and phospho-ERK levels. Transcriptome analysis revealed 1436 genes regulated by AKT and 654 genes regulated by the ERK pathway. Among these, 94 genes were commonly downregulated and 11 genes were commonly upregulated in both datasets, while 110 genes were oppositely regulated. Bioinformatics analysis revealed that the inhibition of the PI3K-AKT and MEK-ERK pathways downregulates key reproductive processes and upstream molecules. Notably, AKT inhibition affected FSH, ESRRG and HIF1 pathways, while ERK inhibition impacted CG, FOS, TGFβ, EGR1 and LH pathways. Transcriptome data showed that genes related to estradiol production were inhibited by ERK and induced by the AKT pathway. This was verified by radioimmunoassays, and mRNA and protein analysis of CYP19A1 and STAR genes. In addition, transcriptome data suggested the downregulation of glucose metabolism in GCs. Using validation experiments, we confirm that both pathways are essential for glucose uptake, lactate production and mitochondrial activity in GCs. These data provide a resource for informing future research for analyzing various novel candidate genes regulated by the AKT and ERK pathways in GCs and other cell types.

The signaling landscape of insulin-like growth factor 1

The sheer amplitude of biological actions of insulin-like growth factor I (IGF-1) affecting all types of cells in all tissues suggests a vast signaling landscape for this ubiquitous humoral signal. While the canonical signaling pathways primarily involve the Ras/MAPK and PI3K/AKT cascades, the evolutionary conservation of insulin-like peptides (ILPs) and their pathways hints at the potential for novel functions to emerge over time. Indeed, the evolutionary trajectory of ILPs opens the possibility of either novel functions for these two pathways, novel downstream routes, or both. Evidence supporting this notion includes observations of neofunctionalization in bony fishes or crustaceans, and the involvement of ILPs pathways in invertebrate eusociality or in vertebrate bone physiology, respectively. Such evolutionary processes likely contribute to the rich diversity of ILPs signaling observed today. Moreover, the interplay between conserved signaling pathways, such as those implicated in aging (predominantly involving the PI3K-AKT route), and lesser known pathways, such as those mediated by biased G-protein coupled receptors and others even less known, may underpin the context-dependent actions characteristic of ILPs signaling. While canonical IGF-1 signaling is often assumed to account for the intracellular pathways utilized by this growth factor, a comprehensive analysis of all the pathways mediated by the IGF-1 receptor (IGF-1R) remains lacking. This review aims to explore both canonical and non-canonical routes of IGF-1R action across various cell types, offering a detailed examination of the mechanisms underlying IGF-1 signaling and highlighting the significant gaps in our current understanding.

Acupuncture Increased the Number of Retrieved Oocytes in a Mouse Model of POR: The Involvement of DNA Methylation in the Oocytes

BACKGROUND

Poor ovarian response (POR) reduces the success rate of in vitro fertilization mainly because of fewer oocytes retrieved. Acupuncture (Ac) therapy can improve the number of retrieved oocytes in the controlled ovarian stimulation program. The role of Ac in the corresponding epigenetic mechanism of POR has not been studied.

OBJECTIVE

This study was conducted to determine the effect of Ac on the number of retrieved oocytes and its role in DNA methylation in a mouse model of POR.

METHODS

Forty C57BL/6N female mice with normal estrous cycles were randomly classified into 4 groups of 10 each: control (Con) group, Ac-Con group, POR group, and Ac-POR group. Mice in POR and Ac-POR groups received a gastric gavage of Tripterygium wilfordii polyglycoside suspension of 50 mg/kg-1 once a day for 14 consecutive days. Ac was applied at "Shenting" (DU 24), "Guanyuan" (CV 4), "Zusanli" (ST 36), and "Shenshu" (BL 23) in the Ac-POR group for 10 min per session, once a day for 14 consecutive days. All four groups were stimulated with pregnant mare serum gonadotropin and human chorionic gonadotropin, and the number of retrieved oocytes and proportion of mature oocytes were recorded. The DNA methylation level in a single mouse oocyte in each group was analyzed using single-cell genome-wide bisulfite sequencing (scBSseq), and key pathways were identified using GO and KEGG enrichment analyses.

RESULTS

A dissecting microscope revealed that the Ac therapy improved the number of retrieved oocytes compared with the POR group (p < 0.05). ScBS-seq showed that there was no significant change in global DNA methylation levels between the POR model and control group mice. However, differences were primarily observed in the differentially methylated regions (DMRs) of each chromosome, and Ac decreased global DNA methylation. DMR analysis identified 13 genes that may be associated with Ac treatment. Cdk5rap2 and Igf1r, which mediate germ cell apoptosis, growth, and development, maybe most closely related to the Ac treatment of POR. KEGG analysis revealed that differentially expressed genes were mainly enriched in Wnt, GnRH, and calcium signaling pathways. The genes were closely related to the regulation of POR via Ac.

CONCLUSION

The results suggest that DNA methylation in oocytes is related to the development of POR and that the role of Ac in affecting DNA methylation in oocytes is associated with the Wnt, GnRH, and calcium signaling pathways as well as Cdk5rap2 and Igf1r in POR mice.

Gene expression levels in cumulus cells are correlated with developmental competence of bovine oocytes

The generation of mammalian embryos by in vitro culture is hampered by the failure of many of the embryos to develop to the blastocyst stage. This problem occurs even when cumulus-oocyte complexes (COCs) with good morphology are visually selected and used for culture. Because cumulus cells are important for oocyte maturation and subsequent embryo development, here we compared gene expression patterns in cumulus cells of COCs that developed in vitro to the blastocyst stage with those of COCs that failed to develop. Cumulus cells were aspirated from bovine COCs selected for in vitro culture. Oocyte developmental competence was evaluated by screening for cleavage and development to the blastocyst stage. The collected cumulus cells were used to quantify mRNA levels of FSH receptor (FSHR), insulin-like growth factor-1 receptor (IGF-1R), anti-Müllerian hormone (AMH), AMH receptor II (AMHRII), epidermal growth factor receptor (EGFR), estrogen receptor β (ERβ), B cell lymphoma/leukemia-2 associated X (Bax), and cysteine-aspartic acid protease-3 (Caspase-3). We found that the expression levels of FSHR, IGF-1R, AMH, and EGFR were higher in cumulus cells from COCs that developed to blastocysts as compared with those that failed to develop, whereas expression levels of Bax and Caspase-3 were lower in cumulus cells of COCs that matured to the blastocyst stage. Positive correlations were found between FSHR and IGF-1R expression (r = 0.59) and between ERβ and EGFR expression (r = 0.43) in cumulus cells from COCs that developed to the blastocyst stage. Our findings indicate that gene expression levels in cumulus cells are correlated with the developmental competence of bovine oocytes. Measurement of gene expression in cumulus cells therefore offers a non-invasive means of predicting oocyte developmental competence.

Acephate Exposure Induces Transgenerational Ovarian Developmental Toxicity by Altering the Expression of Follicular Growth Markers in Female Rats

Acephate is an organophosphate foliar and soil insecticide that is used worldwide. In this study, the transgenerational ovarian developmental toxicity caused by acephate, along with its in utero reprogramming mechanisms, were explored. Thirty female virgin Wistar albino rats were randomly assigned to three groups: one control group and two acephate treatment groups. The treatment groups received daily low or high doses of acephate (34.2 mg/kg or 68.5 mg/kg body weight, respectively) from gestational day 6 until spontaneous labor, resulting in F1 offspring. At 28 days, a subgroup of F1 females were euthanized. The ovaries were extracted, thoroughly cleaned, and weighed before being fixed for further analysis. The remaining F1 females were mated with normal males to produce the F2 generation. The F1 female offspring presented reduced fertility and body weight, whereas the ovarian weight index and sex ratio increased in a dose-dependent manner. Structural analysis revealed altered follicular abnormalities with ovarian cells displaying pyknotic nuclei. Additionally, the gene and protein expression of Cyp19 decreased, whereas that of Gdf-9 increased in the high-dose treatment group (68.5 mg/kg). We also observed significantly increased expression levels of ovarian estrogen receptor 1 (Esr1) and insulin-like growth factor 1 (Igf1), whereas Insl3 expression was significantly decreased. The F2 female offspring presented reproductive phenotype alterations similar to those of F1 females including decreased fertility, reduced Cyp19 gene and protein expression, and structural ovarian abnormalities similar to those of polycystic ovary syndrome (PCOS). In conclusion, acephate induced ovarian developmental toxicity across two generations of rats, which may be linked to changes in the ovarian Cyp19, Gdf9, Insl3, and Igf1 levels.

Dynamics of IGF Signaling During the Ovulatory Peak in Women Undergoing Ovarian Stimulation

CONTEXT

Insulin-like growth factor (IGF) signaling is known to affect human ovarian follicular function during growth and development. However, the role of the IGF system is unknown during the ovulatory peak, which is characterized by profound changes in granulosa cell (GCs) mitosis and function.

OBJECTIVE

How is the IGF system expressed and regulated during the midcycle surge in women?

METHODS

Follicular fluid (FF) and GCs were collected during the ovulatory peak from 2 specific time points. One sample was obtained before oocyte pickup (OPU): before ovulation trigger (OT) (T = 0 hours) or at 12, 17, or 32 hours after OT, and 1 sample was obtained at OPU 36 hours after OT. Fifty women undergoing ovarian stimulation at a university hospital were included. Gene expression profiles were assessed by microarray analysis of GCs. IGF-related proteins in the FF were assessed by immunoassay or by determination of activity with a proteinase assay.

RESULTS

Gene expression of proteins promoting IGF activity (ie, IGF2, PAPP-A, and IRS1) together with proliferation markers were downregulated on a transcriptional level in GCs after OT, whereas proteins inhibiting the IGF signal (ie, IGFBPs, IGF2, and STC1) were upregulated. STC1 gene expression and protein levels were greatly upregulated after OT with a parallel steep downregulation of PAPP-A proteolytic activity.

CONCLUSION

These data suggest that downregulation of IGF signaling mediated by increased STC1 expression is instrumental for the sudden cessation in GC proliferation and onset of differentiation during the ovulatory peak.

Characterization of a novel IGFBP-2 transcript in the ovarian granulosa cells of chicken follicles: mRNA expression, function and effect of reproductive hormones and IGF1

Insulin-like growth factor binding protein-2 (IGFBP-2), a binding protein of insulin-like growth factor (IGF) system, regulates the activity of IGFs and also influences cellular function with endogenous activity. In mammals, IGFBP-2 is reported to affect ovarian follicle development and steroidogenesis; however, its role in the chicken ovary is unknown. In this study, we investigated the mRNA expression and function of a novel IGFBP-2 transcript and the effect of reproductive hormones and insulin-like growth factor 1 (IGF1) on its expression in the ovarian granulosa cells of chicken follicles. The mRNA expression of IGFBP-2 was significantly increased in granulosa cells after follicle selection and was higher in hierarchical granulosa cells (Post-GCs) than in pre-hierarchical granulosa cells (Pre-GCs). IGFBP-2 promoted the proliferation and inhibited the apoptosis of both Pre-GCs and Post-GCs, enhanced the mRNA expression of genes involved in progesterone (P4) synthesis in Pre-GCs. However, in Post-GCs, IGFBP-2 inhibited the mRNA expression of these genes and suppressed P4 secretion. The mRNA expression of IGFBP-2 was inhibited by estradiol (E2) and follicle-stimulating hormone (FSH), but enhanced by P4 in Pre-GCs. In Post-GCs, FSH and IGF1 stimulated the mRNA expression of IGFBP-2 synergistically. Knockdown of IGFBP-2 attenuated the stimulatory effect of IGF1 on the mRNA expression of the side chain cleavage enzyme cytochrome P450 family 11 subfamily A member 1 (CYP11A1). These findings indicate that IGFBP-2 is regulated by FSH and IGF1, exerts different functions in Pre-GCs and Post-GCs in regulating IGF1 and plays an important role in chicken follicle development by affecting granulosa cell proliferation and P4 synthesis.

GHRH and reproductive systems: Mechanisms, functions, and clinical implications

Growth hormone-releasing hormone (GHRH) has classically been considered a regulatory neuropeptide of the hypothalamic-pituitary system, which mediates its anabolic effects through hepatic GH/IGF-I axis. However, during the last decades it has been demonstrated that this key regulatory hormone may be produced in numerous peripheral tissues outside the central nervous system, participating in fundamental physiological functions through a complex balance between its purely endocrine action, and the recently local (autocrine/paracrine) discovered role. Among peripheral sites, its presence in the male and female reproductive systems stands out. In this review, we will first explore the role of the GHRH/GHRH-R hormone axis as a central player in the gonadal function; then, we will discuss available information regarding the presence of GHRH/GHRH-R and the potential physiological roles in reproductive systems of various species; and finally, we will address how reproductive system-related disorders-such as infertility problems, endometriosis, or tumor pathologies (including prostate, or ovarian cancer)-could benefit from hormonal interventions related to the manipulation of the GHRH axis.

Slit1 inhibits ovarian follicle development and female fertility in mice†

Previous in vitro studies have suggested that SLIT ligands could play roles in regulating ovarian granulosa cell proliferation and gene expression, as well as luteolysis. However, no in vivo study of Slit gene function has been conducted to date. Here, we investigated the potential role of Slit1 in ovarian biology using a Slit1-null mouse model. Female Slit1-null mice were found to produce larger litters than their wild-type counterparts due to increased ovulation rates. Increased ovarian weights in Slit1-null animals were found to be due to the presence of greater numbers of healthy antral follicles with similar numbers of atretic ones, suggesting both an increased rate of follicle recruitment and a decreased rate of atresia. Consistent with this, treatment of cultured granulosa cells with exogenous SLIT1 induced apoptosis in presence or absence of follicle-stimulating hormone, but had no effect on cell proliferation. Although few alterations in the messenger RNA levels of follicle-stimulating hormone-responsive genes were noted in granulosa cells of Slit1-null mice, luteinizing hormone target gene mRNA levels were greatly increased. Finally, increased phospho-AKT levels were found in granulosa cells isolated from Slit1-null mice, and SLIT1 pretreatment of cultured granulosa cells inhibited the ability of both follicle-stimulating hormone and luteinizing hormone to increase AKT phosphorylation, suggesting a mechanism whereby SLIT1 could antagonize gonadotropin signaling. These findings therefore represent the first evidence for a physiological role of a SLIT ligand in the ovary, and define Slit1 as a novel autocrine/paracrine regulator of follicle development.

Transcriptome Analysis of Hypothalamic-Pituitary-Ovarian Axis Reveals circRNAs Related to Egg Production of Bian Chicken

The hypothalamic-pituitary-ovarian (HPO) axis plays a pivotal role in the regulation of egg production in chickens. In addition to the traditional understanding of the HPO axis, emerging research highlights the significant role of circRNAs in modulating the functions of this axis. In the study, we collected hypothalamus, pituitary, and ovarian tissues from low-yielding and high-yielding Bian chickens for transcriptome sequencing. We identified 339, 339, and 287 differentially expressed (DE) circRNAs with p_value < 0.05 and |log2 (fold change)| ≥ 1 in hypothalamus, pituitary, and ovarian tissues. The Gene Ontology (GO) enrichment analysis for the source genes of DE circRNAs has yielded multiple biological process (BP) entries related to cell development, the nervous system, and proteins, including cellular component morphogenesis, cell morphogenesis, nervous system development, neurogenesis, protein modification process, and protein metabolic process. In the top 30 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, we observed the enrichment of the GnRH signaling pathway in both the hypothalamus and the pituitary, solely identified the GnRH secretion pathway in the pituitary, and discovered the pathway of oocyte meiosis in the ovary. Furthermore, given that circRNA primarily functions through the ceRNA mechanism, we constructed ceRNA regulatory networks with DE circRNAs originating from the GnRH signaling pathway, GnRH secretion, ovarian steroidogenesis, steroid hormone biosynthesis, and the estrogen signaling pathway. Finally, several important ceRNA regulatory networks related to reproduction were discovered, such as novel_circ_003662-gga-let-7b/miR-148a-3p/miR-146a-5p/miR-146b-5p and novel_circ_003538-gga-miR-7464-3p-SLC19A1. This study will contribute to advancements in understanding the involvement of circRNAs in the HPO axis, potentially leading to innovations in improving egg production and poultry health.

IGF-1 Acts through Kiss1-expressing Cells to Influence Metabolism and Reproduction

Objective

Kisspeptin, encoded by the Kiss1 gene, ties puberty and fertility to energy status; however, the metabolic factors that control Kiss1-expressing cells need to be clarified.

Methods

To evaluate the impact of IGF-1 on the metabolic and reproductive functions of kisspeptin producing cells, we created mice with IGF-1 receptor deletion driven by the Kiss1 promoter (IGF1RKiss1 mice). Previous studies have shown IGF-1 and insulin can bind to each other's receptor, permitting IGF-1 signaling in the absence of IGF1R. Therefore, we also generated mice with simultaneous deletion of the IGF1R and insulin receptor (IR) in Kiss1-expressing cells (IGF1R/IRKiss1 mice).

Results

Loss of IGF1R in Kiss1 cells caused stunted body length. In addition, female IGF1RKiss1 mice displayed lower body weight and food intake plus higher energy expenditure and physical activity. This phenotype was linked to higher proopiomelanocortin (POMC) expression and heightened brown adipose tissue (BAT) thermogenesis. Male IGF1RKiss1 mice had mild changes in metabolic functions. Moreover, IGF1RKiss1 mice of both sexes experienced delayed puberty. Notably, male IGF1RKiss1 mice had impaired adulthood fertility accompanied by lower gonadotropin and testosterone levels. Thus, IGF1R in Kiss1-expressing cells impacts metabolism and reproduction in a sex-specific manner. IGF1R/IRKiss1 mice had higher fat mass and glucose intolerance, suggesting IGF1R and IR in Kiss1-expressing cells together regulate body composition and glucose homeostasis.

Conclusions

Overall, our study shows that IGF1R and IR in Kiss1 have cooperative roles in body length, metabolism, and reproduction.

A Dose-Response Study on Functional and Transcriptomic Effects of FSH on Ex Vivo Mouse Folliculogenesis

Follicle-stimulating hormone (FSH) binds to its membrane receptor (FSHR) in granulosa cells to activate various signal transduction pathways and drive the gonadotropin-dependent phase of folliculogenesis. Both FSH insufficiency (due to genetic or nongenetic factors) and FSH excess (as encountered with ovarian stimulation in assisted reproductive technology [ART]) can cause poor female reproductive outcomes, but the underlying molecular mechanisms remain elusive. Herein, we conducted single-follicle and single-oocyte RNA sequencing analysis along with other approaches in an ex vivo mouse folliculogenesis and oogenesis system to investigate the effects of different concentrations of FSH on key follicular events. Our study revealed that a minimum FSH threshold is required for follicle maturation into the high estradiol-secreting preovulatory stage, and such threshold is moderately variable among individual follicles between 5 and 10 mIU/mL. FSH at 5, 10, 20, and 30 mIU/mL induced distinct expression patterns of follicle maturation-related genes, follicular transcriptomics, and follicular cAMP levels. RNA sequencing analysis identified FSH-stimulated activation of G proteins and downstream canonical and novel signaling pathways that may critically regulate follicle maturation, including the cAMP/PKA/CREB, PI3K/AKT/FOXO1, and glycolysis pathways. High FSH at 20 and 30 mIU/mL resulted in noncanonical FSH responses, including premature luteinization, high production of androgen and proinflammatory factors, and reduced expression of energy metabolism-related genes in oocytes. Together, this study improves our understanding of gonadotropin-dependent folliculogenesis and provides crucial insights into how high doses of FSH used in ART may impact follicular health, oocyte quality, pregnancy outcome, and systemic health.

Lactation body condition loss impaired conceptus development and plasma progesterone concentration at day 8 post-ovulation in primiparous sows

The current study investigated effects of dietary amino acid (AA) availability on lactational body condition loss and metabolic status, in relation to reproductive parameters after weaning up to Day 8 post-ovulation. Primiparous sows (n = 35) were allocated to one of two lactation diets containing either low crude protein (CP, 140 g/kg) with a low percentage (8%) of slow protein in total protein (LL, n = 18) or high CP (180 g/kg) with a high (16%) percentage of slow protein (HH, n = 17). The HH diet was expected to improve AA utilization by supplying more AA, in a more gradual fashion. The diets did not affect sow body condition loss during lactation, while the HH diet tended to increase litter weight gain during the week 3 of lactation (Δ = 1.3 kg, P = 0.09). On Day 14 post-farrowing, HH diet led to higher plasma urea both pre-feeding and post-feeding (Δ = 2.3 mmol/L, P < 0.01, Δ = 2.4 mmol/L, P < 0.01, respectively), whilst plasma creatinine, NEFA and IGF-1 were similar. No dietary effects on reproductive parameters were found, however several relationships were found between body condition and reproductive parameters. Sows with higher body weight on Day 1 or Day 21 post-farrowing had greater follicle size on Day 3 post-weaning (β = 0.03 mm/kg, P < 0.01, β = 0.04 mm/kg, P < 0.01, respectively). At Day 8 post-ovulation, plasma progesterone concentration was negatively related to loin muscle loss (β = -0.67 ng/ml · mm-1, P = 0.02), backfat loss (β = -2.33 ng/ml · mm-1, P = 0.02), and estimated body fat loss (β = -0.67 ng/ml · mm-1, P = 0.02). Both plasma progesterone and the number of corpora lutea were positively related to the energy balance during lactation (β = 0.03 ng/ml · ME MJ-1, P = 0.01, β = 0.01 CL/ME MJ, P = 0.02, respectively). The conceptus size at Day 8 post-ovulation was negatively related to body weight loss (β = -0.01 mm/kg, P = 0.01), estimated body fat loss (β = -0.02 mm/kg, P = 0.03) and estimated body protein loss (β = -0.06 mm/kg, P = 0.04), and was positively related to the energy balance during lactation (β = 5.2*10-4 mm/ME MJ, P = 0.01). In conclusion, body protein and fat losses during lactation reduced subsequent plasma progesterone concentration and conceptus development at Day 8 post-ovulation.

A matter of new life and cell death: programmed cell death in the mammalian ovary

BACKGROUND

The mammalian ovary is a unique organ that displays a distinctive feature of cyclic changes throughout the entire reproductive period. The estrous/menstrual cycles are associated with drastic functional and morphological rearrangements of ovarian tissue, including follicular development and degeneration, and the formation and subsequent atrophy of the corpus luteum. The flawless execution of these reiterative processes is impossible without the involvement of programmed cell death (PCD).

MAIN TEXT

PCD is crucial for efficient and careful clearance of excessive, depleted, or obsolete ovarian structures for ovarian cycling. Moreover, PCD facilitates selection of high-quality oocytes and formation of the ovarian reserve during embryonic and juvenile development. Disruption of PCD regulation can heavily impact the ovarian functions and is associated with various pathologies, from a moderate decrease in fertility to severe hormonal disturbance, complete loss of reproductive function, and tumorigenesis. This comprehensive review aims to provide updated information on the role of PCD in various processes occurring in normal and pathologic ovaries. Three major events of PCD in the ovary-progenitor germ cell depletion, follicular atresia, and corpus luteum degradation-are described, alongside the detailed information on molecular regulation of these processes, highlighting the contribution of apoptosis, autophagy, necroptosis, and ferroptosis. Ultimately, the current knowledge of PCD aberrations associated with pathologies, such as polycystic ovarian syndrome, premature ovarian insufficiency, and tumors of ovarian origin, is outlined.

CONCLUSION

PCD is an essential element in ovarian development, functions and pathologies. A thorough understanding of molecular mechanisms regulating PCD events is required for future advances in the diagnosis and management of various disorders of the ovary and the female reproductive system in general.

Evaluation of growth hormone deficiency in women with unexplained infertility

PURPOSE

Growth hormone (GH) has been recognized to play a regulatory role in female reproduction. It has been reported that infertile GH deficient patients regained fertility after GH replacement. The frequency of GH deficiency is not established in patients diagnosed with unexplained infertility. Here, we aim to present the prevalence of GH deficieny in this patient group.

METHODS

We included patients diagnosed with unexplained infertility throughout 18 months. Insulin tolerance test (ITT) and glucagon stimulation tests (GST) were performed and insufficient response to both tests was required for the diagnosis of GH deficiency.

RESULTS

Twenty-five patients were included in the study, the mean age was 27.4 ± 4.5 years and the median duration of infertility was 60 months (min:14, max:120). Two patients were GH deficient according to GST and 14 to ITT. Two patients (8%) showed lack of response on both tests and were diagnosed with GH deficiency.

CONCLUSION

The rate of GH deficiency among women with unexplained infertility was 8% in this preliminary study. There is need for further studies with larger patient groups to verify the results.

Metabolic hormones are integral regulators of female reproductive health and function

The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.

Molecular crosstalk between insulin-like growth factors and follicle-stimulating hormone in the regulation of granulosa cell function

Background

The last phase of folliculogenesis is driven by follicle-stimulating hormone (FSH) and locally produced insulin-like growth factors (IGFs), both essential for forming preovulatory follicles.

Methods

This review discusses the molecular crosstalk of the FSH and IGF signaling pathways in regulating follicular granulosa cells (GCs) during the antral-to-preovulatory phase.

Main findings

IGFs were considered co-gonadotropins since they amplify FSH actions in GCs. However, this view is not compatible with data showing that FSH requires IGFs to stimulate GCs, that FSH renders GCs sensitive to IGFs, and that FSH signaling interacts with factors downstream of AKT to stimulate GCs. New evidence suggests that FSH and IGF signaling pathways intersect at several levels to regulate gene expression and GC function.

Conclusion

FSH and locally produced IGFs form a positive feedback loop essential for preovulatory follicle formation in all species. Understanding the mechanisms by which FSH and IGFs interact to control GC function will help design new interventions to optimize follicle maturation, perfect treatment of ovulatory defects, improve in vitro fertilization, and develop new contraceptive approaches.

Exploring the Impact of Controlled Ovarian Stimulation and Non-Invasive Oocyte Assessment in ART Treatments

Invasive and noninvasive features are normally applied to select developmentally competent oocytes and embryos that can increase the take-home baby rates in assisted reproductive technology. The noninvasive approach mainly applied to determine oocyte and embryo competence has been, since the early days of IVF, the morphological evaluation of the mature cumulus-oocyte complex at the time of pickup, first polar body, zona pellucida thickness, perivitelline space and cytoplasm appearance. Morphological evaluation of oocyte quality is one of the options used to predict successful fertilization, early embryo development, uterine implantation and the capacity of an embryo to generate a healthy pregnancy to term. Thus, this paper aims to provide an analytical revision of the current literature relating to the correlation between ovarian stimulation procedures and oocyte/embryo quality. In detail, several aspects of oocyte quality such as morphological features, oocyte competence and its surrounding environment will be discussed. In addition, the main noninvasive features as well as novel approaches to biomechanical parameters of oocytes that might be correlated with the competence of embryos to produce a healthy pregnancy and live birth will be illustrated.

The effects of apelin on IGF1/FSH-induced steroidogenesis, proliferation, Bax expression, and total antioxidant capacity in granulosa cells of buffalo ovarian follicles

Apelin (APLN) was believed to be an adipokine secreted from adipose tissue. However, studies demonstrate that it is a pleiotropic peptide and has several effects on the female reproductive system. In this study, We examined the effects of different doses of IGF1 and FSH in the presence of APLN-13 on the production of progesterone in buffalo ovary granulosa cells. Furthermore, different doses of APLN isoforms (APLN-13 and APLN-17) were tested on proliferation, Bax protein expression, and antioxidant capacity in the same cells. Granulosa cells of buffalo ovaries were cultured in the presence of different doses of IGF1 and FSH with or without APLN-13 (10-9 M) to evaluate its effect on the secretion of progesterone tested by ELISA assay. The WST-1 method was used to survey the effect of APLN on granulosa cell proliferation and cytotoxicity. In addition, the antioxidant capacity of the cells in the presence of APLN was assessed using the FRAP method. mRNA and Bax protein levels were measured in granulosa cells treated with APLN using real-time PCR and western blot techniques. APLN-13 (10-9) stimulated the effect of IGF1 on the production of progesterone, and its levels were affected by APLN-13 dose-dependently. However, it did not significantly stimulate the effect of FSH on the secretion of progesterone. APLN-13 (all doses) and APLN-17 (10-8 and 10-9 M) improved the proliferation of granulosa cells. Moreover, preincubation of the cells for an hour by APLN receptor antagonist (ML221, 10 µM) did not significantly affect the proliferation of cells induced by APLN. Neither APLN-13 nor APLN-17 were not cytotoxic for the cells compared to the control treatment. APLN-13 at the doses of 10-6 and 10-8 M substantially up and down-regulated Bax protein expression; however, such effects were not observed when the cells were preincubated with ML221. In addition, APLN-17 did not influence the expression amount of Bax. Furthermore, both APLN-13 and -17 improved the total antioxidant capacity of the ovarian granulosa cells, but such effects were not seen when the cells were preincubated with ML221. According to these results, APLN enhanced the steroidogenesis induced by IGF1 but did not affect the steroidogenesis induced by FSH. APLN also enhanced the cell proliferation and antioxidant capacity of buffalo ovaries follicular granulosa cells; however, its effect on Bax expression was different.

Human-relevant exposure to di-n-butyl phthalate tampers with the ovarian insulin-like growth factor 1 system and disrupts folliculogenesis in young adult mice

Phthalates are compounds used in consumer and medical products worldwide. Phthalate exposure in women has been demonstrated by detection of phthalate metabolites in their urine and ovarian follicular fluid. High urinary phthalate burden has been associated with reduced ovarian reserve and oocyte retrieval in women undergoing assisted reproduction. Unfortunately, no mechanistic explanation for these associations is available. In short term in vivo and in vitro animal studies modeling human-relevant exposures to di-n-butyl phthalate (DBP), we have identified ovarian folliculogenesis as a target for phthalate exposures. In the present study, we investigated whether DBP exposure negatively influences insulin-like growth factor 1 (IGF1) signaling in the ovary and disrupts ovarian folliculogenesis. CD-1 female mice were exposed to corn oil (vehicle) or DBP (10 µg/kg/day, 100 µg/kg/day, or 1000 mg/kg/day) for 20-32 days. Ovaries were collected as animals reached the proestrus stage to achieve estrous cycle synchronization. Levels of mRNAs encoding IGF1 and 2 (Igf1 and Igf2), IGF1 receptor (Igf1r), and IGF-binding proteins 1-6 (Ifgbp1-6) were measured in whole ovary homogenates. Ovarian follicle counts and immunostaining for phosphorylated IGF1R protein (pIGF1R) were used to evaluate folliculogenesis and IGF1R activation, respectively. DBP exposure, at a realistic dose that some women may experience (100 µg/kg/day for 20-32 days), reduced ovarian Igf1 and Igf1r mRNA expression and reduced small ovarian follicle numbers and primary follicle pIGF1R positivity in DBP-treated mice. These findings reveal that DBP tampers with the ovarian IGF1 system and provide molecular insight into how phthalates could influence the ovarian reserve in females.

Physiological and metabolic aspects of follicular developmental competence as affected by lactational body condition loss

Metabolic demands of modern hybrid sows have increased over the years, which increases the chance that sows enter a substantial negative energy balance (NEB) during lactation. This NEB can negatively impact reproductive outcome, which is especially evident in primiparous sows causing a reduced second parity reproductive performance. The negative effects of the lactational NEB on reproductive performance can be partly explained by the influence of the premating metabolic state, during and after lactation, on the development of follicles from which oocytes will give rise to the next litter. In addition, the degree and type of body tissue mobilization during lactation that is, adipose tissue or lean mass, highly influences follicular development. Research investigating relations between the premating metabolic state and follicular and oocyte competence in modern hybrid sows, which experience higher metabolic demands during lactation, is limited. In this review we summarize current knowledge of physiological relations between the metabolic state of modern hybrid sows and follicular developmental competence. In addition, we discuss potential implications of these relations for current sow management strategies.

Effects of Cyanobacterial Harmful Algal Bloom Toxin Microcystin-LR on Gonadotropin-Dependent Ovarian Follicle Maturation and Ovulation in Mice

BACKGROUND

Cyanobacterial harmful algal blooms (CyanoHABs) originate from the excessive growth or bloom of cyanobacteria often referred to as blue-green algae. They have been on the rise globally in both marine and freshwaters in recently years with increasing frequency and severity owing to the rising temperature associated with climate change and increasing anthropogenic eutrophication from agricultural runoff and urbanization. Humans are at a great risk of exposure to toxins released from CyanoHABs through drinking water, food, and recreational activities, making CyanoHAB toxins a new class of contaminants of emerging concern.

OBJECTIVES

We investigated the toxic effects and mechanisms of microcystin-LR (MC-LR), the most prevalent CyanoHAB toxin, on the ovary and associated reproductive functions.

METHODS

Mouse models with either chronic daily oral or acute intraperitoneal exposure, an engineered three-dimensional ovarian follicle culture system, and human primary ovarian granulosa cells were tested with MC-LR of various dose levels. Single-follicle RNA sequencing, reverse transcription-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, western blotting, immunohistochemistry (IHC), and benchmark dose modeling were used to examine the effects of MC-LR on follicle maturation, hormone secretion, ovulation, and luteinization.

RESULTS

Mice exposed long term to low-dose MC-LR did not exhibit any differences in the kinetics of folliculogenesis, but they had significantly fewer corpora lutea compared with control mice. Superovulation models further showed that mice exposed to MC-LR during the follicle maturation window had significantly fewer ovulated oocytes. IHC results revealed ovarian distribution of MC-LR, and mice exposed to MC-LR had significantly lower expression of key follicle maturation mediators. Mechanistically, in both murine and human granulosa cells exposed to MC-LR, there was reduced protein phosphatase 1 (PP1) activity, disrupted PP1-mediated PI3K/AKT/FOXO1 signaling, and less expression of follicle maturation-related genes.

DISCUSSION

Using both in vivo and in vitro murine and human model systems, we provide data suggesting that environmentally relevant exposure to the CyanoHAB toxin MC-LR interfered with gonadotropin-dependent follicle maturation and ovulation. We conclude that MC-LR may pose a nonnegligible risk to women's reproductive health by heightening the probability of irregular menstrual cycles and infertility related to ovulatory disorders. https://doi.org/10.1289/EHP12034.

Human relevant exposure to di-n-butyl phthalate tampers with the ovarian insulin-like growth factor 1 system and disrupts folliculogenesis in young adult mice

Phthalates are compounds used in consumer and medical products worldwide. Phthalate exposure in women has been demonstrated by detection of phthalate metabolites in their urine and ovarian follicular fluid. High urinary phthalate burden has been associated with reduced ovarian reserve and oocyte retrieval in women undergoing assisted reproduction. Unfortunately, no mechanistic explanation for these associations is available. In short term in vivo and in vitro animal studies modeling human relevant exposures to di-n-butyl phthalate (DBP), we have identified ovarian folliculogenesis as a target for phthalate exposures. In the present study, we investigated whether DBP exposure negatively influences insulin-like growth factor 1 (IGF) signaling in the ovary and disrupts ovarian folliculogenesis. CD-1 female mice were exposed to corn oil (vehicle) or DBP (10 or 100 μg/kg/day) for 20-32 days. Ovaries were collected as animals reached the proestrus stage to achieve estrous cycle synchronization. Levels of mRNAs encoding IGF1 and 2 ( Igf1 and Igf2 ), IGF1 receptor ( Igf1r ), and IGF binding proteins 1-6 ( Ifgbp1-6 ) were measured in whole ovary homogenates. Ovarian follicle counts and immunostaining for phosphorylated IGF1R protein (pIGF1R) were used to evaluate folliculogenesis and IGF1R activation, respectively. DBP exposure, at a realistic dose that some women may experience (100 μg/kg/day for 20-32 days), reduced ovarian Igf1 and Igf1r mRNA expression and reduced small ovarian follicle numbers and primary follicle pIGF1R positivity in DBP-treated mice. These findings reveal that DBP tampers with the ovarian IGF1 system and provide molecular insight into how phthalates could influence the ovarian reserve in females.

Alterations in gonadotropin, apoptotic and metabolic pathways in granulosa cells warrant superior fertility of the Dummerstorf high fertility mouse line 1

The development and maturation of ovarian follicles is a complex and highly regulated process, which is essential for successful ovulation. During recent decades, several mouse models provided insights into the regulation of folliculogenesis. In contrast to the commonly used transgenic or knockout mouse models, the Dummerstorf high-fertility mouse line 1 (FL1) is a worldwide unique selection experiment for increased female reproductive performance and extraordinary high fertility. Interactions of cycle-related alterations of parameters of the hypothalamic pituitary gonadal axis and molecular factors in the ovary lead to improved follicular development and therefore increased ovulation rates in FL1 mice. FL1 females almost doubled the number of ovulated oocytes compared to the unselected control mouse line. To gain insights into the cellular mechanisms leading to the high fertility phenotype we used granulosa cells isolated from antral follicles for mRNA sequencing. Based on the results of the transcriptome analysis we additionally measured hormones and growth factors associated with follicular development to complement the picture of how the signaling pathways are regulated. While IGF1 levels are decreased in FL1 mice in estrus, we found no differences in insulin, prolactin and oxytocin levels in FL1 mice compared to the control line. The results of the mRNA sequencing approach revealed that the actions of insulin, prolactin and oxytocin are restricted local to the granulosa cells, since hormonal receptor expression is differentially regulated in FL1 mice. Additionally, numerous genes, which are involved in important gonadotropin, apoptotic and metabolic signaling pathways in granulosa cells, are differentially regulated in granulosa cells of FL1 mice.We showed that an overlap of different signaling pathways reflects the crosstalk between gonadotropin and growth factor signaling pathways, follicular atresia in FL1 mice is decreased due to improved granulosa cell survival and by improving the efficiency of intracellular signaling, glucose metabolism and signal transduction, FL1 mice have several advantages in reproductive performance and therefore increased the ovulation rate. Therefore, this worldwide unique high fertility model can provide new insights into different factors leading to improved follicular development and has the potential to improve our understanding of high fertility.

Insulin-like growth factor 1 enhances follicle-stimulating hormone-induced phosphorylation of GATA4 in rat granulosa cells

Preovulatory granulosa cell (GC) differentiation is essential for the maturation and release of oocytes from the ovary. We have previously demonstrated that follicle-stimulating hormone (FSH) and insulin-like growth factors (IGFs) closely interact to control GC function. Similarly, we showed that GATA4 mediates FSH actions and it is required for preovulatory follicle formation. This report aimed to determine in vivo the effect of FSH on GATA4 phosphorylation and to investigate whether FSH and IGF1 interact to regulate GATA4 activity. In rat ovaries, treatment with equine chorionic gonadotropin (eCG) increased the phosphorylation of GATA4, which was confined to the nucleus of GCs. Using primary rat GCs, we observed that GATA4 phosphorylation at serine 105 increases the transcriptional activity of this transcription factor. Like FSH, IGF1 stimulated GATA4 phosphorylation at serine 105. Interestingly, GATA4 phosphorylation was significantly higher in cells cotreated with FSH and IGF1 when compared to FSH or IGF1 alone, suggesting that IGF1 augments the effects of FSH on GATA4. It was also found that the enhancing effect of IGF1 requires AKT activity and is mimicked by the inhibition of glycogen synthase kinase-3 β (GSK3β), suggesting that AKT inhibition of GSK3β may play a role in the regulation of GATA4 phosphorylation. The data support an important role of the IGF1/AKT/GSK3β signaling pathway in the regulation of GATA4 transcriptional activity and provide new insights into the mechanisms by which FSH and IGF1 regulate GC differentiation. Our findings suggest that GATA4 transcriptional activation may, at least partially, mediate AKT actions in GCs.

“Adipose-derived mesenchymal stem cell therapy for the management of female sexual dysfunction: Literature reviews and study design of a clinical trial”

Hormone imbalance and female sexual dysfunction immensely affect perimenopausal female health and quality of life. Hormone therapy can improve female hormone deficiency, but long-term use increases the risk of cardiovascular diseases and cancer. Therefore, it is necessary to develop a novel effective treatment to achieve long-term improvement in female general and sexual health. This study reviewed factors affecting syndromes of female sexual dysfunction and its current therapy options. Next, the authors introduced research data on mesenchymal stromal cell/mesenchymal stem cell (MSC) therapy to treat female reproductive diseases, including Asherman’s syndrome, premature ovarian failure/primary ovarian insufficiency, and vaginal atrophy. Among adult tissue-derived MSCs, adipose tissue-derived stem cells (ASCs) have emerged as the most potent therapeutic cell therapy due to their abundant presence in the stromal vascular fraction of fat, high proliferation capacity, superior immunomodulation, and strong secretion profile of regenerative factors. Potential mechanisms and side effects of ASCs for the treatment of female sexual dysfunction will be discussed. Our phase I clinical trial has demonstrated the safety of autologous ASC therapy for women and men with sexual hormone deficiency. We designed the first randomized controlled crossover phase II trial to investigate the safety and efficacy of autologous ASCs to treat female sexual dysfunction in perimenopausal women. Here, we introduce the rationale, trial design, and methodology of this clinical study. Because aging and metabolic diseases negatively impact the bioactivity of adult-derived MSCs, this study will use ASCs cultured in physiological oxygen tension (5%) to cope with these challenges. A total of 130 perimenopausal women with sexual dysfunction will receive two intravenous infusions of autologous ASCs in a crossover design. The aims of the proposed study are to evaluate 1) the safety of cell infusion based on the frequency and severity of adverse events/serious adverse events during infusion and follow-up and 2) improvements in female sexual function assessed by the Female Sexual Function Index (FSFI), the Utian Quality of Life Scale (UQOL), and the levels of follicle-stimulating hormone (FSH) and estradiol. In addition, cellular aging biomarkers, including plasminogen activator inhibitor-1 (PAI-1), p16 and p21 expression in T cells and the inflammatory cytokine profile, will also be characterized. Overall, this study will provide essential insights into the effects and potential mechanisms of ASC therapy for perimenopausal women with sexual dysfunction. It also suggests direction and design strategies for future research.

Comparative transcriptome provides insights into differentially expressed genes between testis and ovary of Onychostoma macrolepis in reproduction period

The Onychostoma macrolepis (O. macrolepis) is a rare and endangered fishery species inhabiting the river of Qinling Mountains and some flowing freshwaters in China. The declining population of O. macrolepis caused by asynchrony of male and female development prompted us to focus on genetic regulation of its reproduction. In this study, high-throughput RNA-sequencing technology was applied to assemble and annotate the transcriptome of O. macrolepis testis and ovary. The results showed that a number of 338089335 (ovary:163216500, testis:174872835) raw sequences were obtained. After non-redundant analysis, a number of 207826065 (ovary:102334008, testis:105492057) high quality reads were obtained and predicted as unigenes, in which 201,038,682 unigenes were annotated with multiple databases. Taking the ovarian transcriptome as a control, comparative transcriptome analysis showed that 9918 differentially expressed genes (DEGs) up-regulated in the testis and 13,095 DEGs down-regulated. Many DEGs were involved with sex-related GO terms and KEGG pathways, such as oocyte maturation, gonadal development, steroid biosynthesis pathways, MAPK signaling pathway and Wnt signaling pathway. Finally, the expression patterns of 19 unigenes were validated by using quantitative real-time polymerase chain reaction (qRT-PCR). This study illustrates a potential molecular mechanism on the unsynchronized male and female development of the O. macrolepis during the reproduction period in June and provides a theoretical basis for future artificial reproduction.

The insulin-like growth factor and its players: their functions, significance, and consequences in all aspects of ovarian physiology

Background

Insulin-like growth factor (IGF) has unique and well-known functions in female fertility, according to documents reporting improved yield of oocytes, reinforced quality of the embryo, and enhanced live births with simultaneous reduction of miscarriage. However, there is no detailed information on the bio-mechanisms linking such clinical differences.

Main body

IGF and its receptors are expressed in a variety of tissues in the reproductive system such as granulosa cells, oocytes, and theca cells. Hence, the development of female gametes may be directly regulated by IGF, thereby affecting gamete quality and so its competence for implantation. IGF is a central player in changing the fate of cells during survival and proliferation through the modulation of leading signaling pathways, including Jak/STAT, MAP kinase/ERK, and PI3K/Akt, and subsequent impacts on steroidogenesis and cell division.

Conclusion

The current review aims to scrutinize the performance of IGF to regulate the normal ovarian, and its impacts on cell signaling pathways and resulting alterations in steroidogenesis and cell proliferation. The function of IGF and its receptor has been reviewed in female fertility at both molecular and biochemical levels.

Leptin Promotes Primordial Follicle Activation by Regulating Ovarian Insulin-like Growth Factor System in Chicken

Leptin and insulin-like growth factor 1 (IGF-1) regulate follicle development and reproduction in vertebrates. This study investigated the role played by leptin and IGF-1 in primordial follicle activation in the ovary of 7-day-old chicks. Different doses of leptin were intraperitoneally administrated to female layer chicks, and further analyses were performed. While leptin administration did not affect hepatic leptin receptor (LEPR), growth hormone receptor (GHR), or IGF-1, the lower dose of leptin significantly increased the messenger RNA (mRNA) expression of IGF-1, IGF-1 receptor, and IGF-binding protein (IGFBP)-2 and attenuated anti-Müllerian hormone (AMH) gene expression in the ovary. Furthermore, the ovaries of the same age chicks were challenged with leptin and/or IGF-1 in vitro. Leptin at a lower dose increased the mRNA expression of IGF-1, LEPR, and leptin; 100 ng/mL leptin and 10 ng/mL IGF-1 alone or combined with leptin reduced IGFBP-2 mRNA expression. AMH gene expression was also reduced by all doses except 10 ng/mL leptin. Histological studies showed that a lower dose of leptin injection induced the primordial follicle growth in the ovary in vivo, and the number of primordial follicles was higher in all leptin treatments over control in vitro. Moreover, the luciferase assay revealed that leptin enhanced IGF-1 promoter activity in LEPR-expressing CHO-K1 cells. Collectively, these results indicate that leptin directly affects the IGF-1/IGFBP system and promotes primordial follicular growth in the ovary of early posthatch chicks. In addition, the follicular development by leptin-induced IGF-1 is, at least in part, caused by the suppression of AMH in the ovary.

Prenatal Exposure to Delta-9-tetrahydrocannabinol (THC) Alters the Expression of miR-122-5p and Its Target Igf1r in the Adult Rat Ovary

As cannabis use during pregnancy increases, it is important to understand its effects on the developing fetus. Particularly, the long-term effects of its psychoactive component, delta-9-tetrahydrocannabinol (THC), on the offspring’s reproductive health are not fully understood. This study examined the impact of gestational THC exposure on the miRNA profile in adult rat ovaries and the possible consequences on ovarian health. Prenatal THC exposure resulted in the differential expression of 12 out of 420 evaluated miRNAs. From the differentially expressed miRNAs, miR-122-5p, which is highly conserved among species, was the only upregulated target and had the greatest fold change. The upregulation of miR-122-5p and the downregulation of its target insulin-like growth factor 1 receptor (Igf1r) were confirmed by RT-qPCR. Prenatally THC-exposed ovaries had decreased IGF-1R-positive follicular cells and increased follicular apoptosis. Furthermore, THC decreased Igf1r expression in ovarian explants and granulosa cells after 48 h. As decreased IGF-1R has been associated with diminished ovarian health and fertility, we propose that these THC-induced changes may partially explain the altered ovarian follicle dynamics observed in THC-exposed offspring. Taken together, our data suggests that prenatal THC exposure may impact key pathways in the developing ovary, which could lead to subfertility or premature reproductive senescence.

The use of intraovarian injection of autologous platelet rich plasma (PRP) in patients with poor ovarian response and premature ovarian insufficiency

PURPOSE OF REVIEW

Intraovarian injection of platelet rich plasma (PRP) is a novel treatment for patients with poor ovarian response (POR) and primary ovarian insufficiency (POI). This article reviews the latest literature on the effect of PRP on markers of ovarian reserve, oocyte and embryo yield, and live birth for these poor prognosis patients.

RECENT FINDINGS

Several case series and one prospective trial have demonstrated improvements in markers of ovarian reserve in patients with POI and POR and improved oocyte and embryo yields in patients with POR. These studies report multiple live births in patients who had previously failed treatment. The positive effects of PRP persist throughout the literature despite the fact that multiple protocols for preparing and injecting PRP exist, with no consensus on the optimal protocol.

SUMMARY

Intra-ovarian injection of PRP is a promising new technology for poor prognosis patients. Rigorous and appropriately controlled clinical trials are warranted to confirm the utility of this treatment for improving patients' ability to successfully conceive.

Effects of IGF-1 on the Three-Dimensional Culture of Ovarian Preantral Follicles and Superovulation Rates in Mice

Insulin-like growth factor-1 (IGF-1) plays a crucial role during folliculogenesis, which has been demonstrated by previous research. However, the optimal IGF-1 dosage in the three-dimensional (3D) culture system is unknown. Mouse secondary follicles (140−150 µm) were cultured for 6 days within an alginate bead in a medium supplemented with 0 (G0), 5 ng/mL (G5), 10 ng/mL (G10), or 50 ng/mL IGF-1 (G50). Secretions of 17β-estradiol and progesterone were significantly increased in G10 and G50 (p < 0.05). However, G50 significantly inhibited follicular growth (p < 0.05), while G10 showed a higher oocyte maturation rate. Thus, the 10 ng/mL IGF-1 was used in subsequent experiments. IGF-1 enhanced the function of granulosa cells (GCs) by upregulating expressions of Star, Cyp19a1, Hsd3b1, Fshr, and Lhcgr. Oocyte secretory function was promoted by upregulating expressions of Bmp-15, Gdf-9, and Fgf-8. Addition of IGF-1 showed anti-apoptotic effect. However, G10 did not improve fertilization rate of MII oocytes compared to G0. In an intraperitoneal injection experiment in mice, IGF-1 significantly increased the number of ovulated oocytes (p < 0.05). In conclusion, 10 ng/mL IGF-1 can promote the production of mature oocytes in the 3D culture medium and injection of IGF-1 before superovulation increases the number of ovulated oocytes.

Inositols in the ovaries: activities and potential therapeutic applications

INTRODUCTION

Myo-inositol (MI) and d-chiro-inositol (DCI) play a key role in ovarian physiology, as they are second messengers of insulin and gonadotropins. Ex-vivo and in-vitro experiments demonstrate that both isomers are deeply involved in steroid biosynthesis, and that reduced MI-to-DCI ratios are associated with pathological imbalance of sex hormones.

AREAS COVERED

This expert opinion provides an overview of the physiological distribution of MI and DCI in the ovarian tissues, and a thorough insight of their involvement into ovarian steroidogenesis. Insulin resistance and compensatory hyperinsulinemia dramatically reduce the MI-to-DCI ratio in the ovaries, leading to gynecological disorders characterized by hyperandrogenism, altered menstrual cycle and infertility.

EXPERT OPINION

Available evidence indicates that MI and DCI have very specific physiological roles and, seemingly, physiological MI-to-DCI ratios in the ovaries are crucial to maintain the correct homeostasis of steroids. Inositol treatments should be evaluated on the patients' specific conditions and needs, as long-term supplementation of high doses of DCI may cause detrimental effects on the ovarian functionality. In addition, the effects of inositol therapy on the different PCOS phenotypes should be further investigated in order to better tailor the supplementation.

Sperm-carried IGF2 downregulated the expression of mitogens produced by Sertoli cells: A paracrine mechanism for regulating spermatogenesis?

INTRODUCTION

Insulin-like growth factor 2 (IGF2) mRNA has been found in human and mouse spermatozoa. It is currently unknown whether the IGF2 protein is expressed in human spermatozoa and, if so, its possible role in the cross-talk between germ and Sertoli cells (SCs) during spermatogenesis.

METHODS

To accomplish this, we analyzed sperm samples from four consecutive Caucasian men. Furthermore, to understand its role during the spermatogenetic process, porcine SCs were incubated with increasing concentrations (0.33, 3.33, and 10 ng/mL) of recombinant human IGF2 (rhIGF2) for 48 hours. Subsequently, the experiments were repeated by pre-incubating SCs with the non-competitive insulin-like growth factor 1 receptor (IGF1R) inhibitor NVP-AEW541. The following outcomes were evaluated: 1) Gene expression of the glial cell-line derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), and stem cell factor (SCF) mitogens; 2) gene and protein expression of follicle-stimulating hormone receptor (FSHR), anti-Müllerian hormone (AMH), and inhibin B; 3) SC proliferation.

RESULTS

We found that the IGF2 protein was present in each of the sperm samples. IGF2 appeared as a cytoplasmic protein localized in the equatorial and post-acrosomal segment and with a varying degree of expression in each cell. In SCs, IGF2 significantly downregulated GDNF gene expression in a concentration-dependent manner. FGF2 and SCF were downregulated only by the highest concentration of IGF2. Similarly, IGF2 downregulated the FSHR gene and FSHR, AMH, and inhibin B protein expression. Finally, IGF2 significantly suppressed the SC proliferation rate. All these findings were reversed by pre-incubation with NVP-AEW541, suggesting an effect mediated by the interaction of IGF2 with the IGFR.

CONCLUSION

In conclusion, sperm IGF2 seems to downregulate the expression of mitogens, which are known to be physiologically released by the SCs to promote gonocyte proliferation and spermatogonial fate adoption. These findings suggest the presence of paracrine regulatory mechanisms acting on the seminiferous epithelium during spermatogenesis, by which germ cells can influence the amount of mitogens released by the SCs, their sensitivity to FSH, and their rate of proliferation.

Mechanism of negative modulation of FSH signaling by salt-inducible kinases in rat granulosa cells

The optimal development of preovulatory follicles needs follicle-stimulating hormone (FSH). Recent findings revealed that salt-inducible kinases (SIKs) inhibit FSH actions in humans and rodents. This report seeks to increase our understanding of the molecular mechanisms controlled by SIKs that participate in the inhibition of FSH actions in primary rat granulosa cells (GCs). The results showed that FSH causes a transient induction of Sik1 mRNA. In contrast, SIK inhibition had no effects on FSH receptor expression. Next, we determined whether SIK inhibition enhances the effect of several sequential direct activators of the FSH signaling pathway. The findings revealed that SIK inhibition stimulates the induction of steroidogenic genes by forskolin, cAMP, protein kinase A (PKA), and cAMP-response element-binding protein (CREB). Strikingly, FSH stimulation of CREB and AKT phosphorylation was not affected by SIK inhibition. Therefore, we analyzed the expression and activation of putative CREB cofactors and demonstrated that GCs express CREB-regulated transcriptional coactivators (CRTC2) and that FSH treatment and SIK inhibition increase the nuclear expression of this factor. We concluded that SIKs target the FSH pathway by affecting factors located between cAMP/PKA and CREB and propose that SIKs control the activity of CRTC2 in ovarian GCs. The findings demonstrate for the first time that SIKs blunt the response of GCs to FSH, cAMP, PKA, and CREB, providing further evidence for a crucial role for SIKs in regulating ovarian function and female fertility.

Growth hormone for in vitro fertilisation (IVF)

BACKGROUND

In an effort to improve outcomes of in vitro fertilisation (IVF) cycles, the use of growth hormone (GH) has been considered as adjuvant treatment in ovarian stimulation. Improving the outcomes of IVF is especially important for women with infertility who are considered 'poor responders'. We have compared the outcomes of IVF with adjuvant GH versus no adjuvant treatment in routine use, and specifically in poor responders.

OBJECTIVES

To assess the effectiveness and safety of growth hormone as an adjunct to IVF compared to standard IVF for women with infertility SEARCH METHODS: We searched the following databases (to November 2020): Cochrane Gynaecology and Fertility (CGF) Group specialised register, CENTRAL, MEDLINE, Embase, CINAHL, Epistemonikos database and trial registers together with reference checking and contact with study authors and experts in the field to identify additional trials.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) of adjuvant GH treatment in IVF compared with no adjuvant treatment for women with infertility. We excluded trials where additional adjuvant treatments were used with GH. We also excluded trials comparing different IVF protocols.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Two review authors independently performed assessment of trial risk of bias and extraction of relevant data. The primary review outcome was live birth rate. The secondary outcomes were clinical pregnancy rate, oocytes retrieved, embryo transfer, units of gonadotropin used and adverse events, i.e. ectopic pregnancy, multiple pregnancy, ovarian hyperstimulation syndrome (OHSS), congenital anomalies, oedema.

MAIN RESULTS

We included 16 RCTs (1352 women). Two RCTs (80 women) studied GH in routine use, and 14 RCTs (1272 women) studied GH in poor responders. The evidence was low to very low certainty, the main limitations being risk of bias, imprecision and heterogeneity. Adjuvant growth hormone compared to no adjuvant: routine use for in vitro fertilisation (IVF) The evidence is very uncertain about the effect of GH on live birth rate per woman randomised for routine use in IVF (odds ratio (OR) 1.32, 95% confidence interval (CI) 0.40 to 4.43; I2 = 0%; 2 trials, 80 participants; very low-certainty evidence). If the chance of live birth without adjuvant GH is assumed to be 15%, the chance of live birth with GH would be between 6% and 43%. There was insufficient evidence to reach a conclusion regarding clinical pregnancy rates per woman randomised, number of women with at least one oocyte retrieved per woman randomised and embryo transfer achieved per woman randomised; reported data were unsuitable for analysis. The evidence is very uncertain about the effect of GH on mean number of oocytes retrieved in normal responders (mean difference (MD) -0.02, 95% CI -0.79 to 0.74; I2 = 0%; 2 trials, 80 participants; very low-certainty evidence). The evidence is very uncertain about the effect of GH on mean units of gonadotropin used in normal responders (MD 13.57, 95% CI -112.88 to 140.01; I2 = 0%; 2 trials, 80 participants; very low-certainty evidence). We are uncertain of the effect of GH on adverse events in normal responders. Adjuvant growth hormone compared to no adjuvant: use in poor responders for in vitro fertilisation (IVF) The evidence is very uncertain about the effect of GH on live birth rate per woman randomised for poor responders (OR 1.77, 95% CI 1.17 to 2.70; I2 = 0%; 8 trials, 737 participants; very low-certainty evidence). If the chance of live birth without adjuvant GH is assumed to be 11%, the chance of live birth with GH would be between 13% and 25%. Adjuvant GH results in a slight increase in pregnancy rates in poor responders (OR 1.85, 95% CI 1.35 to 2.53; I2 = 15%; 11 trials, 1033 participants; low-certainty evidence). The results suggest, if the pregnancy rate without adjuvant GH is assumed to be 15%, with GH the pregnancy rate in poor responders would be between 19% and 31%. The evidence suggests that GH results in little to no difference in number of women with at least one oocyte retrieved (OR 5.67, 95% CI 1.54 to 20.83; I2 = 0%; 2 trials, 148 participants; low-certainty evidence). If the chance of retrieving at least one oocyte in poor responders was 81%, with GH the chance is between 87% and 99%. There is a slight increase in mean number of oocytes retrieved with the use of GH for poor responders (MD 1.40, 95% CI 1.16 to 1.64; I2 = 87%; 12 trials, 1153 participants; low-certainty evidence). The evidence is very uncertain about the effect of GH on embryo transfer achieved (OR 2.32, 95% CI 1.08 to 4.96; I2 = 25%; 4 trials, 214 participants; very low-certainty evidence). If the chance of achieving embryo transfer is assumed to be 77%, the chance with GH will be 78% to 94%. Use of GH results in reduction of mean units of gonadotropins used for stimulation in poor responders (MD -1088.19, 95% CI -1203.20 to -973.18; I2 = 91%; 8 trials, 685 participants; low-certainty evidence). High heterogeneity in the analyses for mean number of oocytes retrieved and units of GH used suggests quite different effects according to differences including in trial protocols (populations, GH dose and schedule), so these results should be interpreted with caution. We are uncertain of the effect of GH on adverse events in poor responders as six of the 14 included trials failed to report this outcome.

AUTHORS' CONCLUSIONS

The use of adjuvant GH in IVF treatment protocols has uncertain effect on live birth rates and mean number of oocytes retrieved in normal responders. However, it slightly increases the number of oocytes retrieved and pregnancy rates in poor responders, while there is an uncertain effect on live birth rates in this group. The results however, need to be interpreted with caution, as the included trials were small and few in number, with significant bias and imprecision. Also, the dose and regimen of GH used in trials was variable. Therefore, further research is necessary to fully define the role of GH as adjuvant therapy in IVF.

Intrauterine endogenous high glucocorticoids program ovarian dysfunction in female offspring secondary to prenatal caffeine exposure

Ovarian dysfunction has an intrauterine origin, and prenatal caffeine exposure (PCE) could lead to abnormal follicle counts in offspring after birth. However, the effect of PCE on offspring ovarian function and its mechanism of intrauterine programming have not been reported thus far. In this study, pregnant Wistar rats were intragastrically administered caffeine (30 and 120 mg/kg·d) at gestational days 9-20 (GD9-20). Certain tests were performed on the blood, ovaries and hypothalamus of female offspring at different time points. PCE female offspring had ovarian dysfunction in adulthood compared with the control. Further results showed that in utero ovarian morphological development and estradiol synthesis were inhibited but rapidly increased during puberty in the PCE group. The histone 3 lysine 27 acetylation (H3K27ac) level of the insulin-like growth factor 1 (IGF1) promoter region and its expression were decreased in the ovary, which was due to exposure to high levels of fetal blood corticosterone, and the H3K27ac level of IGF1 and its expression shifted to increase after birth with a decrease in serum corticosterone levels. Chronic stress led to increased serum corticosterone levels in adult offspring, whereas ovarian morphological development, the H3K27ac level of IGF1 and its expression, and estradiol synthesis were significantly inhibited. Moreover, the activity of the hypothalamic-pituitary-ovarian (HPO) axis was increased in the early postnatal period of PCE offspring, and chronic stress reversed these changes. In the KGN cell line, it was found that cortisol could promote the translocation of the glucocorticoid receptor (GR) into the nucleus and upregulate histone deacetylase 10 (HDAC10) to inhibit the H3K27ac level of IGF1 and its expression and estradiol synthesis. In summary, PCE is associated with ovarian dysfunction in female adult offspring, and the potential mechanism is related to intrauterine high glucocorticoid exposure by activating the GR and recruiting HDAC10 to affect ovarian glucocorticoid-IGF1 axis programming and to inhibit estradiol synthesis.

Igf3: a novel player in fish reproduction†

As in other vertebrates, fish reproduction is tightly controlled by gonadotropin signaling. One of the most perplexing aspects of gonadotropin action on germ cell biology is the restricted expression of gonadotropin receptors in somatic cells of the gonads. Therefore, the identification of factors conveying the action of gonadotropins on germ cells is particularly important for understanding the mechanism of reproduction. Insulin-like growth factors (Igfs) are recognized as key factors in regulating reproduction by triggering a series of physiological processes in vertebrates. Recently, a novel member of Igfs called Igf3 has been identified in teleost. Different from the conventional Igf1 and Igf2 that are ubiquitously expressed in a majority of tissues, Igf3 is solely or highly expressed in the fish gonads. The role of Igf3 in mediating the action of gonadotropin through Igf type 1 receptor on several aspects of oogenesis and spermatogenesis have been demonstrated in several fish species. In this review, we will summarize existing data on Igf3. This new information obtained from Igf3 provides insight into elucidating the molecular mechanism of fish reproduction, and also highlights the importance of Igf system in mediating the action of gonadotropin signaling on animal reproduction.

Exogenous insulin-like growth factor 1 accelerates growth and maturation of follicles in human cortical xenografts and increases ovarian output in mice

OBJECTIVE

To measure the influence of exogenous insulin-like growth factor 1 (IGF1) on follicle growth and maturation in human ovarian cortical xenografts.

DESIGN

Xenotransplantation model.

SETTING

University-based research laboratory.

PATIENTS/ANIMALS

Ovarian tissue was donated with consent and institutional review board approval by brain-dead organ donors or patients undergoing ovarian tissue cryopreservation for fertility preservation. Cortical fragments were transplanted into immunocompromised mice.

INTERVENTIONS

Cryopreserved ovarian cortical fragments from four women (aged 19, 25, 33, and 46 years) were transplanted into the gluteus muscle of immunocompromised mice in a fibrin matrix containing endothelial cells that were transduced with lentiviral particles encoding secreted IGF1. Xenografts were recovered after 3, 8, and 14 weeks. In addition, C57/Bl6 mice underwent intraovarian injection of saline or recombinant IGF1 (60 μg), followed by superovulation, analysis of ethynyl-deoxyuridine incorporation, and ribonucleic acid sequencing of the whole ovaries.

MAIN OUTCOME MEASURES

For xenografts: follicle count and distribution; antral follicle count; and corpora lutea/albicans count. For mice: follicle count and distribution; oocyte yield, ethynyl-deoxyuridine incorporation (granulosa cell proliferation); and ovarian transcriptomic signature.

RESULTS

At 3 weeks, xenografts in the IGF1 condition revealed a decreased percentage of primary follicles and increased percentage of secondary follicles that were concentrated in the preantral subtype; at 8 weeks, an increase in secondary follicles was concentrated in the simple subtype; after 14 weeks, primordial follicles were reduced, and while the number of advanced follicles did not power the experiment to demonstrate significance, antral follicles reduced and corpora lutea increased. Supporting experiments in mice revealed an increase in normal oocytes following intraovarian injection of recombinant IGF1 (60 μg) as well as increased proliferative index among follicles of secondary and preantral stages. Ribonucleic acid sequencing analysis of the whole ovaries following injection of recombinant IGF1 (25 μg) revealed an acute (24 hours) upregulation of transcripts related to steroidogenesis and luteinization.

CONCLUSIONS

Exogenous IGF1 advances the pace of growth among primordial, primary, and secondary stage follicles but results in near absence of antral stage follicles in long-term (14 weeks) xenografts. In mice, acute administration of IGF1 promotes follicle advance and increased oocyte yield. The results suggest that while superphysiological IGF1 alone advances the pace of growth among early/preantral follicles, a sustained and/or later-stage influence undermines antral follicle growth/survival or promotes premature luteinization. These findings provide a temporal framework for interpreting follicle growth/mobilization and may be useful in understanding the clinical application of human growth hormone in the context of assisted reproduction.

Consequences of negative energy balance on follicular development and oocyte quality in primiparous sows†

Metabolic demands of modern hybrid sows have increased over the years, which increases the chance that sows enter a substantial negative energy balance (NEB) during lactation. This NEB can influence the development of follicles and oocytes that will give rise to the next litter. To study effects of a lactational NEB on follicular development, we used 36 primiparous sows of which 18 were subjected to feed restriction (3.25 kg/day) and 18 were full-fed (6.5 kg/day) during the last 2 weeks of a 24.1 ± 0.3 day lactation. Feed restriction resulted in a 70% larger lactational body weight loss and 76% higher longissimus dorsi depth loss, but similar amounts of backfat loss compared to the full fed sows. These changes were accompanied by lower plasma insulin-like growth factor 1 (IGF1) and higher plasma creatinine levels in the restricted sows from the last week of lactation onward. Ovaries were collected 48 h after weaning. Restricted sows had a lower average size of the 15 largest follicles (−26%) and cumulus–oocyte complexes showed less expansion after 22 h in vitro maturation (−26%). Less zygotes of restricted sows reached the metaphase stage 24 h after in vitro fertilization and showed a higher incidence of polyspermy (+89%). This shows that feed restriction had severe consequences on oocyte developmental competence. Follicular fluid of restricted sows had lower IGF1 (−56%) and steroid levels (e.g., β-estradiol, progestins, and androgens), which indicated that follicles of restricted sows were less competent to produce steroids and growth factors needed for oocytes to obtain full developmental competence.

Current Understandings of Core Pathways for the Activation of Mammalian Primordial Follicles

The mammalian ovary has two main functions-producing mature oocytes for fertilization and secreting hormones for maintaining the ovarian endocrine functions. Both functions are vital for female reproduction. Primordial follicles are composed of flattened pre-granulosa cells and a primary oocyte, and activation of primordial follicles is the first step in follicular development and is the key factor in determining the reproductive capacity of females. The recent identification of the phosphatidylinositol 3 kinase (PI3K)/phosphatase and tensin homolog deleted on chromosome 10 (PTEN) signaling pathway as the key controller for follicular activation has made the study of primordial follicle activation a hot research topic in the field of reproduction. This review systematically summarizes the roles of the PI3K/PTEN signaling pathway in primordial follicle activation and discusses how the pathway interacts with various other molecular networks to control follicular activation. Studies on the activation of primordial follicles have led to the development of methods for the in vitro activation of primordial follicles as a treatment for infertility in women with premature ovarian insufficiency or poor ovarian response, and these are also discussed along with some practical applications of our current knowledge of follicular activation.

Role of Akt and mammalian target of rapamycin signalling in insulin-like growth factor 1-mediated cell proliferation in porcine Sertoli cells

The critical role of insulin-like growth factor (IGF) 1 in promoting Sertoli cell proliferation invivo and invitro has been established, but its downstream signalling mechanisms remain unknown. In addition to mitogenic effects, a role for IGF1 in mediating cholesterol biosynthesis within testes has been implied. The aims of this study were to investigate the roles of: (1) phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (mTOR) signalling in IGF1-mediated Sertoli cell proliferation; and (2) IGF1 in mediating cholesterol biosynthesis in Sertoli cells. Primary cultures of Sertoli cells were prepared from 1-week-old porcine testes. On Day 3 of culture, Sertoli cells were treated with 300ng mL-1 IGF1, alone or in combination with inhibitors of IGF1 receptor (2μM picropodophyllotoxin), Akt (1μM wortmannin) or mTOR (200nM rapamycin). Cells were cultured for 30min and phosphorylation levels of Akt, mTOR and p70 ribosomal protein S6 kinase (p70S6K) were determined by immunoblotting. Cell proliferation and quantitative polymerase chain reaction assays were conducted using cells cultured for 24h. IGF1 increased phosphorylation of Akt, mTOR and p70S6K and cell proliferation, and these effects were inhibited by inhibitors of IGF1R, Akt and mTOR. Furthermore, IGF1 upregulated the expression of cholesterol biosynthetic genes (3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS1) and cytochrome P450, family 5, subfamily A, polypeptide 1 (CYP5A1)), but not sterol regulatory element-binding transcription factor 1 (SREBF1). Increased phosphorylation of p70S6K, a major downstream target of mTOR, and upregulated expression of genes involved in cholesterol biosynthesis are indicative of the key role played by IGF1 in regulating the synthesis of cholesterol, the precursor for steroid hormones.

Oocyte-secreted factors strongly stimulate sFRP4 expression in human cumulus cells

Secreted frizzled-related protein-4 (SFRP4) belongs to a family of soluble ovarian-expressed proteins that participate in female reproduction, particularly in rodents. In humans, SFRP4 is highly expressed in cumulus cells (CCs). However, the mechanisms that stimulate SFRP4 in CCs have not been examined. We hypothesise that oocyte-secreted factors such as growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are involved in the regulation of SFRP4. Human CCs were collected from patients undergoing fertility treatments and treated with GDF9 or BMP15 or their combination in the presence of FSH or vehicle. FSH treatment significantly decreased SFRP4 mRNA levels when compared with nontreated cells. However, SFRP4 mRNA levels were increased significantly by GDF9 plus BMP15 in a concentration-dependent manner in the presence or absence of FSH. The combination of GDF9 plus BMP15 also increased SFRP4 protein levels and decreased the activity of the β-catenin/T cell factor-responsive promoter significantly. GDF9 plus BMP15 inhibited steroidogenic acute regulatory protein and LH/hCG receptor stimulation by FSH, while treatment with SFRP4 blocked the stimulatory effect of FSH on these genes. The evidence demonstrates that GDF9 and BMP15 act in coordination to stimulate SFRP4 expression and suggests that SFRP4 mediates the anti-luteinising effects of the oocyte in human CCs.

Recent advances in understanding gonadotropin signaling

Gonadotropins are glycoprotein sex hormones regulating development and reproduction and bind to specific G protein–coupled receptors expressed in the gonads. Their effects on multiple signaling cascades and intracellular events have recently been characterized using novel technological and scientific tools. The impact of allosteric modulators on gonadotropin signaling, the role of sugars linked to the hormone backbone, the detection of endosomal compartments supporting signaling modules, and the dissection of different effects mediated by these molecules are areas that have advanced significantly in the last decade. The classic view providing the exclusive activation of the cAMP/protein kinase A (PKA) and the steroidogenic pathway by these hormones has been expanded with the addition of novel signaling cascades as determined by high-resolution imaging techniques. These new findings provided new potential therapeutic applications. Despite these improvements, unanswered issues of gonadotropin physiology, such as the intrinsic pro-apoptotic potential to these hormones, the existence of receptors assembled as heteromers, and their expression in extragonadal tissues, remain to be studied. Elucidating these issues is a challenge for future research.

Pseudo-Starvation Driven Energy Expenditure Negatively Affects Ovarian Follicle Development

In the present investigation, we examined whether a change in whole body energy fluxes could affect ovarian follicular development, employing mice ectopically expressing uncoupling protein 1 in skeletal muscle (UCP1-TG). Female UCP1-TG and wild-type (WT) mice were dissected at the age of 12 weeks. Energy intake and expenditure, activity, body weight and length, and body composition were measured. Plasma insulin, glucose, leptin, plasma fibroblast growth factor 21 (FGF21) and plasma insulin-like growth factor 1 (IGF1) levels were analyzed and ovarian follicle and corpus luteum numbers were counted. IGF1 signaling was analyzed by immunohistochemical staining for the activation of insulin receptor substrate 1/2 (IRS1/2) and AKT. UCP1-TG female mice had increased energy expenditure, reduced body size, maintained adiposity, and decreased IGF1 concentrations compared to their WT littermates, while preantral and antral follicle numbers were reduced by 40% and 60%, respectively. Corpora lutea were absent in 40% of the ovaries of UCP1-TG mice. Phospho-IRS1, phospho-AKT -Ser473 and -Thr308 immunostaining was present in the granulosa cells of antral follicles in WT ovaries, but faint to absent in the antral follicles of UCP1-TG mice. In conclusion, the reduction in circulating IGF1 levels due to the ectopic expression of UCP1 is associated with reduced immunostaining of the IRS1-PI3/AKT pathway, which may negatively affect ovarian follicle development and ovulation.

Transcriptome Analysis of Long Noncoding RNAs and mRNAs in Granulosa Cells of Jinghai Yellow Chickens Illuminated With Red Light

Jinghai Yellow chickens are a new indigenous breed with a dual purpose in China, but their egg laying performance is limited. Compared with white light (WL), exposure to red light (RL) can improve the egg laying performance of hens. Herein, to elucidate the molecular mechanism by which RL affects the egg laying performance, RNA sequencing was used to analyze long noncoding RNAs (lncRNAs) and mRNAs from granulosa cells of small yellow follicles from Jinghai Yellow chickens in RL and WL groups. A total of 12,466 lncRNAs were identified among the assembled transcripts, of which 168 lncRNAs were significantly different between the RL and WL groups (101 downregulated and 67 upregulated). Additionally, 1182 differentially expressed mRNAs were identified (958 downregulated and 224 upregulated). Integrated network analysis demonstrated that numerous differential mRNAs were involved in follicular development through steroid hormone synthesis, oocyte meiosis, and the PI3K-Akt signaling pathway. The impact of lncRNAs on cis and trans target mRNAs indicates that some lncRNAs play important roles in follicular development of small yellow follicles. The results provide a starting point for studies aimed at understanding the molecular mechanisms by which monochromatic light affects follicular development and egg production in hens.

Ovarian Rejuvenation Using Autologous Platelet-Rich Plasma

Advanced maternal age is associated with the natural oocyte depletion, leading to low oocyte yield, high infertility treatment cancellation rates, and eventual decreases in pregnancy rates. Various innovative interventions have been introduced to improve the outcome of infertility treatment for aging patients. Numerous published data demonstrated that early follicle development was regulated by intraovarian growth factors through autocrine or paracrine mechanisms. Platelet-rich plasma (PRP), a plasma fraction of peripheral blood with a high concentration of platelets, has been implemented in regenerative medicine in the last decade. The plasma contains a variety of growth factors that were suggested to be able to enhance angiogenesis regeneration and the cell proliferation process. The initial report showed that an intraovarian injection of PRP improved the hormonal profile and increased the number of retrieved oocytes in patients with diminished ovarian reserve. Subsequently, several studies with larger sample sizes have reported that this approach resulted in several healthy live births with no apparent complications. However, the use of ovarian PRP treatment needs to be fully investigated, because no randomized controlled trial has yet been performed to confirm its efficacy.