Maternal obesity is associated with ovarian inflammation and upregulation of early growth response factor 1

Impact of high-fat diet on ovarian epigenetics: Insights from altered intestinal butyric acid levels

Objective

To investigate the effects of a high-fat diet (HFD) on the gut bacterium Roseburia intestinalis and butyric acid levels, and to assess their impact on ovarian function and epigenetic markers in mice.

Methods

A total of 20 female ICR mice aged 4 weeks were randomly assigned to two groups and fed either a control diet (CD) or an HFD for 36 weeks. Post-intervention, ileal contents were analyzed for the quantification of butyric acid using ELISA, while feces were obtained for Roseburia intestinalis expression assessment via qPCR. Histological evaluations of intestinal and ovarian tissues included H&E and Alcian Blue-Periodic Acid Schiff (AB-PAS) staining, alongside immunohistochemical analysis for F4/80, and immunofluorescent detection of Occludin, ZO-1, 5 mC, and H3K36me3. Ovarian health was assessed through follicle counts and morphological evaluations. Statistical analyses were performed using GraphPad Prism 8.0, with P < 0.05 considered significant.

Results

After 36 weeks, the HFD group showed significantly higher body weight compared to the CD group (P < 0.01). The HFD led to a decrease in Roseburia intestinalis and butyric acid levels, a reduction in intestinal goblet cells, and an increase in intestinal inflammation. Histological analyses revealed impaired ovarian follicular development and enhanced inflammation in the HFD mice, with immunofluorescent staining showing downregulation of the ovarian epigenetic markers 5 mC and H3K36me3.

Conclusion

Our study demonstrates that long-term HFD negatively impacts ovarian function and epigenetic regulation. We found decreased levels of the gut bacterium Roseburia intestinalis and its metabolite, butyric acid, which contribute to these adverse effects. Additionally, the associated intestinal inflammation and compromised mucosal barrier may contribute to these adverse outcomes on female reproductive health.

Intermittent fasting improves the oocyte quality of obese mice through the regulation of maternal mRNA storage and translation by LSM14B

Obesity has significant repercussions for female reproductive health, including adverse effects on oocyte quality, fertility, embryo development and offspring health. Here, we showed that intermittent fasting (IF) has several notable effects on follicular development, oocyte development and maturation and offspring health in obese mice. IF treatment prevents obesity-associated germline-soma communication defects, mitochondrial dysfunction, oxidative damage, apoptosis, and spindle/chromosomal disruption. RNA-sequencing analysis of oocytes from normal diet (ND), high-fat diet (HFD), and HFD + IF mice indicated that IF treatment improved mitochondrial oxidative phosphorylation function and mRNA storage and translation, which was potentially mediated by the Smith-like family member 14 B (LSM14B). Knockdown of LSM14B by siRNA injection in oocytes from ND mice recapitulates all the translation, mitochondrial dysfunction and meiotic defect phenotypes of oocytes from HFD mice. Remarkably, the injection of Lsm14b mRNA into oocytes from HFD mice rescued the translation, mitochondrial dysfunction and meiotic defect phenotypes. These results demonstrated that dysfunction in the oocyte translation program is associated with obesity-induced meiotic defects, while IF treatment increased LSM14B expression and maternal mRNA translation and restored oocyte quality. This research has important implications for understanding the effects of obesity on female reproductive health and offers a potential nonpharmacological intervention to improve oocyte quality and fertility in obese individuals.

Maternal metabolic health and fertility: we should not only care about but also for the oocyte!

Metabolic disorders due to obesity and unhealthy lifestyle directly alter the oocyte's microenvironment and impact oocyte quality. Oxidative stress and mitochondrial dysfunction play key roles in the pathogenesis. Acute effects on the fully grown oocytes are evident, but early follicular stages are also sensitive to metabolic stress leading to a long-term impact on follicular cells and oocytes. Improving the preconception health is therefore of capital importance but research in animal models has demonstrated that oocyte quality is not fully recovered. In the in vitro fertilisation clinic, maternal metabolic disorders are linked with disappointing assisted reproductive technology results. Embryos derived from metabolically compromised oocytes exhibit persistently high intracellular stress levels due to weak cellular homeostatic mechanisms. The assisted reproductive technology procedures themselves form an extra burden for these defective embryos. Minimising cellular stress during culture using mitochondrial-targeted therapy could rescue compromised embryos in a bovine model. However, translating such applications to human in vitro fertilisation clinics is not simple. It is crucial to consider the sensitive epigenetic programming during early development. Research in humans and relevant animal models should result in preconception care interventions and in vitro strategies not only aiming at improving fertility but also safeguarding offspring health.

Effects of an obesogenic diet on the oviduct depend on the duration of feeding

Research question

How long does it take for an obesogenic (high-fat/high-sugar, HF/HS) diet to influence the oviductal microenvironment? What are the affected cellular pathways and are they dependent on the genetic background of the mouse model?

Design

Female Swiss (outbred) and C57BL/6N (B6, inbred) mice were fed either a control (10% fat) or HF/HS (60% fat, 20% fructose) diet. Body weight was measured weekly. Mice were sacrificed at 3 days (3d), 1 week (1w), 4w, 8w, 12w and 16w on the diet (n = 5 per treatment per time point). Total cholesterol concentrations and inflammatory cytokines were measured in serum. Oviductal epithelial cells (OECs) were used to study the expression of genes involved in (mitochondrial) oxidative stress (OS), endoplasmic reticulum (ER) stress and inflammation using qPCR.

Results

Body weight and blood cholesterol increased significantly in the HF/HS mice in both strains compared to controls. In Swiss mice, HF/HS diet acutely increased ER-stress and OS-related genes in the OECs already after 3d. Subsequently, mitochondrial and cytoplasmic antioxidants were upregulated and ER-stress was alleviated at 1w. After 4-8w (mid-phase), the expression of ER-stress and OS-related genes was increased again and persisted throughout the late-phase (12-16w). Serum inflammatory cytokines and inflammatory marker-gene expression in the OECs were increased only in the late-phase. Some of the OEC stress responses were stronger or earlier in the B6.

Conclusions

OECs are sensitive to an obesogenic diet and may exhibit acute stress responses already after a few days of feeding. This may impact the oviductal microenvironment and contribute to diet-induced subfertility.

The physiology of experimental overfeeding in animals

BACKGROUND

Body weight is defended by strong homeostatic forces. Several of the key biological mechanisms that counteract weight loss have been unraveled over the last decades. In contrast, the mechanisms that protect body weight and fat mass from becoming too high remain largely unknown. Understanding this aspect of energy balance regulation holds great promise for curbing the obesity epidemic. Decoding the physiological and molecular pathways that defend against weight gain can be achieved by an intervention referred to as 'experimental overfeeding'.

SCOPE OF THE REVIEW

In this review, we define experimental overfeeding and summarize the studies that have been conducted on animals. This field of research shows that experimental overfeeding induces a potent and prolonged hypophagic response that seems to be conserved across species and mediated by unidentified endocrine factors. In addition, the literature shows that experimental overfeeding can be used to model the development of non-alcoholic steatohepatitis and that forced intragastric infusion of surplus calories lowers survival from infections. Finally, we highlight studies indicating that experimental overfeeding can be employed to study the transgenerational effects of a positive energy balance and how dietary composition and macronutrient content might impact energy homeostasis and obesity development in animals.

MAJOR CONCLUSIONS

Experimental overfeeding of animals is a powerful yet underappreciated method to investigate the defense mechanisms against weight gain. This intervention also represents an alternative approach for studying the pathophysiology of metabolic liver diseases and the links between energy balance and infection biology. Future research in this field could help uncover why humans respond differently to an obesogenic environment and reveal novel pathways with therapeutic potential against obesity and cardiometabolic disorders.

A Systematic Review of the Effects of High-Fat Diet Exposure on Oocyte and Follicular Quality: A Molecular Point of View

Worldwide, infertility affects between 10 and 15% of reproductive-aged couples. Female infertility represents an increasing health issue, principally in developing countries, as the current inclinations of delaying pregnancy beyond 35 years of age significantly decrease fertility rates. Female infertility, commonly imputable to ovulation disorders, can be influenced by several factors, including congenital malformations, hormonal dysfunction, and individual lifestyle choices, such as smoking cigarettes, stress, drug use and physical activity. Moreover, diet-related elements play an important role in the regulation of ovulation. Modern types of diet that encourage a high fat intake exert a particularly negative effect on ovulation, affecting the safety of gametes and the implantation of a healthy embryo. Identifying and understanding the cellular and molecular mechanisms responsible for diet-associated infertility might help clarify the confounding multifaceted elements of infertility and uncover novel, potentially curative treatments. In this view, this systematic revision of literature will summarize the current body of knowledge of the potential effect of high-fat diet (HFD) exposure on oocyte and follicular quality and consequent female reproductive function, with particular reference to molecular mechanisms and pathways. Inflammation, oxidative stress, gene expression and epigenetics represent the main mechanisms associated with mammal folliculogenesis and oogenesis.

The interactions of CAP and LYN with the insulin signaling transducer CBL play an important role in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a hormonal disorder characterized by hyperandrogenism, ovulatory dysfunction, and insulin resistance. Evidence suggests that aberrations in insulin signaling-associated pathways may underlie PCOS pathogenesis. Our aim was to investigate the molecular mechanisms underlying PCOS and associated insulin resistance using in silico analyses, in vitro cell models, and in vivo murine models.

METHODS

R-based bioinformatics analysis was performed on granulosa cell microarray data from three human cohorts: healthy control, PCOS patients without insulin resistance, and PCOS patients with insulin resistance. Transgenic human granulosa cell models were utilized for in vitro studies. Transgenic murine models of dehydroepiandrosterone (DHEA)-induced PCOS were utilized for in vivo studies.

RESULTS

Sorbin and SH3 Domain Containing 1 (SORBS1), the parent gene of the insulin receptor-associated Casitas B-lineage lymphoma protein (CBL)-associated protein (CAP), is a key downregulated gene in PCOS patients with insulin resistance. CAP binding to CBL reduced CBL^Y731 phosphorylation, CBL-phosphoinositide 3-kinase (PI3K) p85α interactivity, protein kinase B (Akt)^S473 phosphorylation, and NFκB-induced inflammatory marker expression but enhanced CRKII-mediated membrane GLUT4 translocation in granulosa cells. In contrast, the tyrosine kinase Lck/Yes-Related Novel Protein (LYN) is upregulated in PCOS patients with insulin resistance. LYN binding to CBL enhanced CBL^Y731 phosphorylation, CBL-PI3K p85α interactivity, Akt^S473 phosphorylation, and NFκB-induced inflammatory marker expression but did not impact membrane GLUT4 translocation. In PCOS mice, Cap overexpression, Cap transactivation by metformin, or enhancing Cbl-CrkII binding improved insulin sensitivity and ovarian dysfunction (i.e., estrous cycle disruption, cyst-like follicle formation, and sex hormone dysregulation). In contrast, Lyn knockdown, Lyn inhibition by PP2, or CBL-PI3K p85α blockade improved only ovarian dysfunction. Cbl^3YF phosphomutant overexpression (which enhances Cbl-CrkII binding but blocks Cbl-PI3K p85α binding) ameliorated both ovarian dysfunction and insulin resistance.

CONCLUSIONS

The interactions of CAP and LYN with CBL, and the resulting effects on CBL phosphorylation and activity, may play an important role in PCOS pathogenesis. Targeting these players may be a viable therapeutic strategy for PCOS.

Novel role of xanthine oxidase-dependent H2O2 production in 12/15-lipoxygenase-mediated de novo lipogenesis, triglyceride biosynthesis and weight gain

12/15-lipoxygenase (12/15-LOX) plays an essential role in oxidative conversion of polyunsaturated fatty acids into various bioactive lipid molecules. Although 12/15-LOX's role in the pathophysiology of various human diseases has been well studied, its role in weight gain is controversial and poorly clarified. Here, we demonstrated the role of 12/15-LOX in high-fat diet (HFD)-induced weight gain in a mouse model. We found that 12/15-LOX mediates HFD-induced de novo lipogenesis (DNL), triglyceride (TG) biosynthesis and the transport of TGs from the liver to adipose tissue leading to white adipose tissue (WAT) expansion and weight gain via xanthine oxidase (XO)-dependent production of H₂O₂. 12/15-LOX deficiency leads to cullin2-mediated ubiquitination and degradation of XO, thereby suppressing H₂O₂ production, DNL and TG biosynthesis resulting in reduced WAT expansion and weight gain. These findings infer that manipulation of 12/15-LOX metabolism may manifest a potential therapeutic target for weight gain and obesity.

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12/15-LOX-12(S)-HETE axis via activation of CREB-Egr1 enhances TG biosynthesis.

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12/15-LOX-12(S)-HETE axis via activation of SREBP1c triggers DNL.

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H₂O₂ mediates 12/15-LOX-12(S)-HETE axis-induced DNL and TG biosynthesis.

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12/15-LOX via TG biosynthesis leads to WAT expansion and body weight gain.

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Downstream to 12/15-LOX, H₂O₂-mediates WAT expansion and body weight gain.

Adiposity is associated with anovulation independent of serum free testosterone: A prospective cohort study

BACKGROUND

Obesity, a body mass index (BMI) ≥30 kg/m2 , is linked to infertility, potentially through a greater risk of anovulation due to elevated androgens. Yet, previous studies have not directly assessed the impact of adiposity, or body fat, on anovulation in the absence of clinical infertility.

OBJECTIVE

To characterise the associations between adiposity and anovulation among women menstruating on a regular basis.

METHODS

Women from the EAGeR trial (n = 1200), a randomised controlled trial of low-dose aspirin and pregnancy loss among women trying to conceive, were used to estimate associations between adiposity and incident anovulation. Participants completed baseline questionnaires and anthropometry, and provided blood specimens. Women used fertility monitors for up to six consecutive menstrual cycles, with collection of daily first morning voids for hormone analysis in the first two menstrual cycles for prospective assessment of anovulation. Anovulation was assessed by urine pregnanediol glucuronide or luteinising hormone concentration or the fertility monitor. Weighted mixed-effects log-binomial regression was used to estimate associations between measures of adiposity and incident anovulation, adjusted for free (bioavailable) testosterone, anti-Mullerian hormone (AMH), serum lipids, and demographic and life style factors.

RESULTS

343 (28.3%) women experienced at least one anovulatory cycle. Anovulation risk was higher per kg/m2 greater BMI (relative risk [RR] 1.03, 95% confidence interval (CI) 1.01, 1.04), cm waist circumference (RR 1.01, 95% CI 1.00, 1.02), mm subscapular skinfold (RR 1.02, 95% CI 1.01, 1.03), and mm middle upper arm circumference (RR 1.04, 95% CI 1.01, 1.06) adjusted for serum free testosterone, AMH, lipids, and other factors.

CONCLUSIONS

Adiposity may be associated with anovulation through pathways other than testosterone among regularly menstruating women. This may account in part for reported associations between greater adiposity and infertility among women having menstrual cycles regularly. Understanding the association between adiposity and anovulation might lead to targeted interventions for preventing infertility.

Different response of embryos originating from control and obese mice to insulin in vitro

The aim of the present work was to investigate the impact of maternal obesity on DNA methylation in ovulated oocytes, and to compare the response of in vitro-developing preimplantation embryos originating from control and obese mice to insulin. An intergenerational, diet-induced obesity model was used to produce outbred mice with an increased body weight and body fat. Two-cell and eight-cell embryos recovered from obese and control mice were cultured in a medium supplemented with 1 or 10 ng/ml insulin until blastocyst formation. In the derived blastocysts, cell proliferation, differentiation, and death rates were determined. The results of immunochemical visualization of 5-methylcytosine indicated a slightly higher DNA methylation in ovulated metaphase II oocytes recovered from obese females; however, the difference between groups did not reach statistical significance. Expanded blastocysts developed from embryos provided by control dams showed increased mean cell numbers (two and eight-cell embryos exposed to 10 ng/ml), an increased inner-cell-mass/trophectoderm ratio (two-cell embryos exposed to 1 ng/ml and eight-cell embryos exposed to 10 ng/ml), and a reduced level of apoptosis (two and eight-cell embryos exposed to 10 ng/ml). In contrast, embryos originating from obese mice were significantly less sensitive to insulin; indeed, no difference was recorded in any tested variable between the embryos exposed to insulin and those cultured in insulin-free medium. Real-time RT-PCR analysis showed a significant increase in the amount of insulin receptor transcripts in blastocysts recovered from obese dams. These results suggest that maternal obesity might modulate the mitogenic and antiapoptotic responses of preimplantation embryos to insulin.

Inflammation in Obesity-Related Complications in Children: The Protective Effect of Diet and Its Potential Role as a Therapeutic Agent

Obesity is a growing health problem in both children and adults, impairing physical and mental state and impacting health care system costs in both developed and developing countries. It is well-known that individuals with excessive weight gain frequently develop obesity-related complications, which are mainly known as Non-Communicable Diseases (NCDs), including cardiovascular disease, type 2 diabetes mellitus, metabolic syndrome, non-alcoholic fatty liver disease, hypertension, hyperlipidemia and many other risk factors proven to be associated with chronic inflammation, causing disability and reduced life expectancy. This review aims to present and discuss complications related to inflammation in pediatric obesity, the critical role of nutrition and diet in obesity-comorbidity prevention and treatment, and the impact of lifestyle. Appropriate early dietary intervention for the management of pediatric overweight and obesity is recommended for overall healthy growth and prevention of comorbidities in adulthood.

The CC-chemokine receptor 2 is involved in the control of ovarian folliculogenesis and fertility lifespan in mice

The chemokine receptor 2 (CCR2) was first described as a chemotactic factor involved in immune responses, but it also plays an essential function in several biological processes. The chemokine (C-C motif) ligand 2 (CCL2) binds to CCR2 triggering G protein-coupled receptor (GPCR) signaling in leukocytes, including activation of PI3K/Akt/mTOR, a key pathway that is also related to follicular activation and survival. However, the potential role of CCR2 in ovarian follicular physiology remain unexplored. Thus, we investigated the role of CCR2 on follicular growth during adult life and aging. Ovaries and oocytes were collected from wild type (WT) mice at 1.5 months old (mo), and CCR2 expression was observed predominantly in oocytes included in growing follicles, as well as after ovulation. Follicle populations were assessed in WT and CCR2-/- mice at 1.5 mo, and CCR2-/- mice had more primordial and less primary and secondary follicles, while there were no differences in antral follicle numbers. Pro-apoptotic genes Bax and Casp3 were downregulated, while anti-apoptotic Bcl2 was upregulated in CCR2-/- mice. To further characterize the role of CCR2 in ovarian aging, follicle populations were assessed in WT and CCR2-/- mice at 1.5, 2.5, 6, 10, and 12 mo. A larger ovarian follicular reserve at 1.5-6 mo was observed in CCR2-/- mice. Finally, CCR2-/- aged mice (6-12 mo) ovulated more oocytes than WT mice. Altogether, these data suggest that CCR2 plays an important role in the regulation of murine folliculogenesis, potentially affecting the reproductive lifespan.

Direct role of the C-C motif chemokine receptor 2/monocyte chemoattractant protein 1 system in the feline cumulus oocyte complex†

Studies were designed to (a) evaluate the mRNA expression of the C-C motif chemokine receptor 2 (CCR2) and its chemokine ligands, as well as genes related to periovulatory events, within the cumulus oocyte complex (COC) and follicle wall after a luteinizing hormone (LH) stimulus in cultured feline antral follicles; (b) assess the immunolocalization of CCR2 and its main ligand (monocyte chemoattractant protein 1, MCP1) within the feline COC; and (c) examine the direct effects of exogenous recombinant MCP1 on mRNA expression of the CCR2 receptor and MCP1 as well as key periovulatory genes in the COC, using a feline COC culture system. Both culture systems were developed by our laboratory and exhibit physiological response to gonadotropin stimuli. In summary, this study demonstrated mRNA expression of CCR2 receptor and its assessed ligands (MCP1, MCP2, MCP3, and MCP4) within the feline COC and follicle antral wall, and a significant increase in CCR2 mRNA by LH within the COC. Also, CCR2 and MCP1 immunoreactivity was observed in the oocyte and cumulus cells of the feline COC. Remarkably, this is the first report, in any species, describing a direct effect of the recombinant MCP1 in the CCR2/MCP1 system within the COC, by increasing the mRNA levels of key genes involved in the ovulatory cascade, as well as its own receptor CCR2. Together, these data suggest that CCR2 receptor signaling in the COC may regulate events critical for promoting cumulus oocyte expansion and/or oocyte maturation.

Effect of body mass index on pregnancy outcomes with the freeze-all strategy in women with polycystic ovarian syndrome

OBJECTIVE

To investigate the effects of body mass index (BMI) on assisted reproductive outcomes with the freeze-all strategy for patients with polycystic ovary syndrome (PCOS).

DESIGN

Retrospective cohort study.

SETTING

Tertiary care academic medical center.

PATIENT(S)

A total of 3,079 women with PCOS across different BMIs at our institution from January 2015 to May 2017 were stratified into cohorts.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Implantation rate, clinical pregnancy rate, early miscarriage rate, and live birth rate.

RESULT(S)

The live birth rate was most favorable in underweight (BMI < 18.5 kg/m²) and normal weight cohorts (18.5 ≤ BMI < 25 kg/m²) and progressively decreased as BMI increased. Moreover, the obese cohort (BMI ≥ 30 kg/m²) of patients with PCOS who had frozen ET cycles had a relatively high early miscarriage rate.

CONCLUSION(S)

The live birth rates are highest in underweight and normal weight patients with PCOS undergoing IVF with the freeze-all strategy. Furthermore, there is a progressive and statistically significant decrease in the live birth rate and an increase in the miscarriage rate in obese patients with PCOS.

Obesity leads to distinct metabolomic signatures in follicular fluid of women undergoing in vitro fertilization

Although obesity negatively influences the metabolic homeostasis of cells within a broad range of tissues, its impact on oocyte metabolism is not fully understood. Prior evidence suggests that obesity increases expression of oocyte genes associated with inflammation, oxidative stress, and lipid metabolism; however, the metabolic impact of these genetic differences is not known. To address this gap, we conducted an exploratory assessment of the follicular fluid (FF) metabolome in eight overweight/obese (OW) and nine normal-weight (NW) women undergoing in vitro fertilization. FF and serum were collected and analyzed by untargeted metabolomics using gas chromatography-quadrupole time-of-flight mass spectrometry and charged-surface hybrid column-electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Untargeted metabolomics identified obesity-associated changes in FF metabolites related to oxidative stress/antioxidant capacity, xenometabolism/amino acid biosynthesis, and lipid metabolism. Discriminant FF metabolites included elevated uric acid, isothreonic acid, one unknown primary metabolite, and six unknown complex lipids in OW compared with NW women. Conversely, 2-ketoglucose dimethylacetal, aminomalonate, two unknown primary metabolites, and two unknown complex lipids were decreased in FF of OW relative to NW women. Indole-3-propionic acid (IPA), a bacteria-derived metabolite, was also decreased in both FF and serum of OW women ( P < 0.05). The significant correlation between antioxidant IPA in serum and FF ( R = 0.95, P < 0.0001) suggests a potential serum biomarker of FF antioxidant status or reflection of the gut metabolism interaction with the follicle. These results suggest that obesity has important consequences for the follicular environment during the preconception period, a window of time that may be important for lifestyle interventions to ameliorate obesity-associated risk factors.

A decade in female reproduction: an endocrine view of the past and into the future

Over the last decade, huge achievements have been made in the fields of neurophysiology, molecular endocrinology, and biochemistry, as well as in the successful translation of clinical research into diseases into clinical practice. As regards female reproduction, most of the advances made in this area were achieved in gonadal axis regulation, regulation of behavior through sex steroids, reproductive genetics, preservation of ovarian reproductive function, steroid profiling, and metabolic and overall reproductive outcomes. The coming years are expected to bring further understanding of the relationships between nutrition, energy metabolism, and reproductive function and to succeed in identifying new genetic markers linked to adverse metabolic and unfavorable cardiovascular outcomes in women. From our perspective, future research in the field of female reproduction should be directed toward doing research into genetic reproductive abnormalities and neuroendocrine diseases, pathophysiology, long-term health outcomes for oligo/amenorrhea, hyperandrogenism, and ovulatory dysfunction. It is additionally expected that a better understanding will be gained of the endocrinology of the placenta and of pregnancy, the role of the microbiome in female reproduction, the role of insulin sensitizers, anti-obesity and anti-diabetic drugs, and various advances in the prevention of ovarian damage caused by various oncology therapies, while new therapeutic options for the treatment of infertility, including kisspeptin, will be developed.

Transcriptome profiling of bovine ovarian theca cells treated with fibroblast growth factor 9

We reported previously that fibroblast growth factor 9 (FGF9) acts as an antidifferentiation factor, stimulating proliferation of granulosa cells (GCs) and theca cells (TCs) while suppressing hormone-induced steroidogenesis of these cells. How FGF9 acts to simultaneously suppress steroidogenesis and stimulate proliferation remains to be fully elucidated. Thus, this study was undertaken to clarify the effects of FGF9 on the TC transcriptome. Ovaries were obtained from beef heifers at a local abattoir, TCs were isolated from large antral follicles, and cultured with or without 30 ng/mL of FGF9 for 24 h in the presence of LH and IGF-1. After treatment, total RNA was extracted from TC and processed for microarray using Affymetrix GeneChip Bovine Genome Arrays (n = 4/group). Transcriptome analysis comparing FGF9-treated TC with control TC using 1.3-fold cutoff, and a P < 0.05 significance level identified 355 differentially expressed transcripts, with 164 elements upregulated and 191 elements downregulated by FGF9. The ingenuity pathway analysis (IPA) was used to investigate how FGF9 treatment affects molecular pathways, biological functions, and the connection between molecules in bovine TC. The IPA software identified 346 pathways in response to FGF9 in TC involved in several biological functions and unveiled interesting relationships among genes related to cell proliferation (eg, CCND1, FZD5, and MYB), antioxidation/cytoprotection (eg, HMOX1 and NQO1), and steroidogenesis (eg, CYP11A1 and STAR). Overall, genes, pathways, and networks identified in this study painted a picture of how FGF9 may regulate folliculogenesis, providing novel candidate genes for further investigation of FGF9 functions in ovarian follicular development.

Obesity Modulates Inflammation and Lipid Metabolism Oocyte Gene Expression: A Single-Cell Transcriptome Perspective

CONTEXT

It is hypothesized that obesity adversely affects the ovarian environment, which can disrupt oocyte maturation and embryonic development.

OBJECTIVE

This study aimed to compare oocyte gene expression profiles and follicular fluid (FF) content from overweight/obese (OW) women and normal-weight (NW) women who were undergoing fertility treatments.

DESIGN

Using single-cell transcriptomic analyses, we investigated oocyte gene expression using RNA sequencing.

PATIENTS OR OTHER PARTICIPANTS

Eleven OW women and 13 NW women undergoing fertility treatments were enrolled.

MAIN OUTCOME MEASURES

Oocyte messenger RNA profiles as well as serum and FF hormone and lipid levels were assessed.

RESULTS

OW women had significantly higher body mass index, body fat percentage, and serum homeostatic model assessment-insulin resistance index compared with NW women (P < 0.01). Serum leptin and C-reactive protein (CRP) levels as well as FF leptin, CRP, and triglyceride levels were increased (P < 0.05) in OW compared with NW women. Oocytes from OW women had increased expression of proinflammatory (CXCL2; P = 0.071) and oxidative stress-related (DUSP1; P = 0.051) genes but had decreased expression of GAS7 (fat metabolism; P = 0.065), TXNIP (oxidative stress; P = 0.055), and transcription factors ID3 (P = 0.075) and TWIST1 (P = 0.099) compared with NW women.

CONCLUSIONS

These findings provide evidence for the significant influence of body composition on oocyte transcript abundance in women undergoing hormonal induction to retrieve oocytes. They further identify the potential for maternal diet to influence oocyte gene expression. The preconception period is, therefore, an important window of opportunity to consider for lifestyle interventions.