Metformin improves polycystic ovary syndrome in mice by inhibiting ovarian ferroptosis

Endoplasmic reticulum stress-mediated ferroptosis in granulosa cells contributes to follicular dysfunction of polycystic ovary syndrome driven by hyperandrogenism

RESEARCH QUESTION

Does hyperandrogenaemia affect the function of ovarian granulosa cells by activating ferroptosis, and could this process be regulated by endoplasmic reticulum stress?

DESIGN

Levels of ferroptosis and endoplasmic reticulum stress in granulosa cells were detected in women with and without polycystic ovary syndrome (PCOS) undergoing IVF. Ferroptosis and endoplasmic reticulum stress levels of ovarian tissue and follicle development were detected in control mice and PCOS-like mice models, induced by dehydroepiandrosterone. An in-vitro PCOS model of KGN cells was constructed with testosterone and ferroptosis inhibitor Fer-1. Endoplasmic reticulum stress inhibitor, tauroursodeoxycholate (TUDCA), determined the potential mechanism associated with excessive induction of ferroptosis in granulosa cells related to PCOS, and levels of ferroptosis and endoplasmic reticulum stress were detected.

RESULTS

Activation of ferroptosis and endoplasmic reticulum stress occurred in granulosa cells of women with PCOS and the varies of PCOS-like mice. The findings in KGN cells demonstrated that testosterone treatment results in elevation of oxidative stress levels, particularly lipid peroxidation, and intracellular iron accumulation in granulosa cells. The expression of genes and proteins associated with factors related to ferroptosis, mitochondrial membrane potential and ultrastructure showed that testosterone activated ferroptosis, whereas Fer-1 reversed these alterations. During in-vitro experiments, activation of endoplasmic reticulum stress induced by testosterone treatment was detected in granulosa cells. In granulosa cells, TUDCA, an inhibitor of endoplasmic reticulum stress, significantly mitigated testosterone-induced ferroptosis.

CONCLUSIONS

Ferroptosis plays a part in reproductive injury mediated by hyperandrogens associated with PCOS, and may be regulated by endoplasmic reticulum stress.

Metformin induces tumor immunogenic cell death in ovarian cancer by activating AMPK pathway

Inducing immunogenic cell death (ICD) process may be an important antitumor strategy in ovarian cancer (OC). Metformin (Met) has been shown to have antitumor effects in OC, but whether it mediates the ICD to inhibit OC process is unclear. Human OC cell lines (SKOV3 and A2780) were treated with Met. Dendritic cell (DC) and CD8+T cells were isolated from the peripheral blood mononuclear cells of volunteers. Cell counting kit 8 assay was used to measure cell viability, and immunofluorescence staining was performed to detect the percentages of membrane and intracellular calreticulin (CRT). CRT level, DC maturation and effector cell activation were evaluated by flow cytometry. The levels of IL-10 and IFN-γ, as well as the releasements of HMGB1 and ATP, were detected using corresponding kits. The protein levels of heat shock protein 70/90 (HSP70/90) and AMPKα were tested by western blot analysis, and the mRNA levels of CD80, CD86, IL-10, and IFN-γ were measured by quantitative real-time PCR. Colony formation assay was utilized for assessing cell cytotoxicity. Mice transplanted tumor model was constructed to assess the effect of Met on OC tumor growth, and immunohistochemistry staining was used to analyze CD80+ and CD86+ cells in mice tumor tissues. Our data showed that Met inhibited OC cell viability and induced CRT exposure. Besides, Met could promote the release of HMGB1 and ATP, as well as induce DC maturation. In vivo experiments suggested that Met restrained OC tumor growth via activating antitumor immune response. Moreover, Met activated AMPK pathway, and silenced AMPK pathway reversed the promoting effect of Met on CRT exposure and the releasements of HMGB1 and ATP in OC cells. In conclusion, Met induced ICD-mediated immune destruction in OC via activating AMPK pathway, indicating that Met might be used in the immunotherapy of OC.

Metformin enhances the survival ability of ovarian granulosa cells in polycystic ovary syndrome by promoting LINC00548 to suppress androgen receptor/klotho pathway

BACKGROUND

Metformin (Met) has been reported to play the key role in the pathogenesis of polycystic ovary syndrome (PCOS). However, the precise mechanisms underlying the actions of Met in PCOS remain incompletely understood. This study aimed to confirm the mechanism of Met interacting with a long non-coding RNA LINC00548 in PCOS.

METHODS

Ovarian granulosa cells (OGCs) were incubated 500 nM dihydrotestosterone (DHT) to construct PCOS in vitro model and then were treated 20 μM Met. A series of cell experiments including Cell Counting Kit-8, Terminal uridine nucleotide end labeling, and flow cytometry were performed to confirm the changes of OGC survival ability. Quantitative real-time polymerase chain reaction was conducted to determine the levels of LINC00548, whereas Western blotting was applied to determine the levels of androgen receptor (AR) and klotho.

RESULTS

Met improved the cell viability and suppressed cell apoptosis in DHT-treated OGCs. LINC00548 downregulated in DHT-treated OGCs was upregulated by Met, and its overexpression further enhanced the positive effects of Met on the survival ability of DHT-treated OGCs. In addition, Met could induce the upregulation of LINC00548 to suppress the activation of AR/klotho pathway in DHT-treated OGCs.

CONCLUSION

Overall, this study discovers that Met enhances the survival ability of OGCs in PCOS by elevating LINC00548 expression to suppress AR/klotho pathway.

Broadening horizons: the role of ferroptosis in polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a common heterogeneous reproductive endocrine metabolic disorder in women of reproductive age characterized by clinical and biochemical hyperandrogenemia, ovulation disorders, and polycystic ovarian morphology. Ferroptosis is a novel type of cell death driven by iron accumulation and lipid peroxidation. Ferroptosis plays a role in maintaining redox balance, iron metabolism, lipid metabolism, amino acid metabolism, mitochondrial activity, and many other signaling pathways linked to diseases. Iron overload is closely related to insulin resistance, decreased glucose tolerance, and the occurrence of diabetes mellitus. There is limited research on the role of ferroptosis in PCOS. Patients with PCOS have elevated levels of ferritin and increased reactive oxygen species in ovarian GCs. Studying ferroptosis in PCOS patients is highly important for achieving personalized treatment. This article reviews the progress of research on ferroptosis in PCOS, introduces the potential connections between iron metabolism abnormalities and oxidative stress-mediated PCOS, and provides a theoretical basis for diagnosing and treating PCOS.

Targeted inhibition of kisspeptin neurons reverses hyperandrogenemia and abnormal hyperactive LH secretion in a preclinical mouse model of polycystic ovary syndrome

STUDY QUESTION

Do hyperactive kisspeptin neurons contribute to abnormally high LH secretion and downstream hyperandrogenemia in polycystic ovary syndrome (PCOS)-like conditions and can inhibition of kisspeptin neurons rescue such endocrine impairments?

SUMMARY ANSWER

Targeted inhibition of endogenous kisspeptin neuron activity in a mouse model of PCOS reduced the abnormally hyperactive LH pulse secretion and hyperandrogenemia to healthy control levels.

WHAT IS KNOWN ALREADY

PCOS is a reproductive disorder characterized by hyperandrogenemia, anovulation, and/or polycystic ovaries, along with a hallmark feature of abnormal LH hyper-pulsatility, but the mechanisms underlying the endocrine impairments remain unclear. A chronic letrozole (LET; aromatase inhibitor) mouse model recapitulates PCOS phenotypes, including polycystic ovaries, anovulation, high testosterone, and hyperactive LH pulses. LET PCOS-like females also have increased hypothalamic kisspeptin neuronal activation which may drive their hyperactive LH secretion and hyperandrogenemia, but this has not been tested.

STUDY DESIGN, SIZE, DURATION

Transgenic KissCRE+/hM4Di female mice or littermates Cre- controls were treated with placebo, or chronic LET (50 µg/day) to induce a PCOS-like phenotype, followed by acute (once) or chronic (2 weeks) clozapine-N-oxide (CNO) exposure to chemogenetically inhibit kisspeptin cells (n = 6 to 10 mice/group).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Key endocrine measures, including in vivo LH pulse secretion patterns and circulating testosterone levels, were assessed before and after selective kisspeptin neuron inhibition and compared between PCOS groups and healthy controls. Alterations in body weights were measured and pituitary and ovarian gene expression was determined by qRT-PCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Acute targeted inhibition of kisspeptin neurons in PCOS mice successfully lowered the abnormally hyperactive LH pulse secretion (P < 0.05). Likewise, chronic selective suppression of kisspeptin neuron activity reversed the previously high LH and testosterone levels (P < 0.05) down to healthy control levels and rescued reproductive gene expression (P < 0. 05).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Ovarian morphology was not assessed in this study. Additionally, mouse models can offer mechanistic insights into neuroendocrine processes in PCOS-like conditions but may not perfectly mirror PCOS in women.

WIDER IMPLICATIONS OF THE FINDINGS

These data support the hypothesis that overactive kisspeptin neurons can drive neuroendocrine PCOS-like impairments, and this may occur in PCOS women. Our findings complement recent clinical investigations using NKB receptor antagonists to lower LH in PCOS women and suggest that pharmacological dose-dependent modulation of kisspeptin neuron activity may be a valuable future therapeutic target to clinically treat hyperandrogenism and lower elevated LH in PCOS women.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by NIH grants R01 HD111650, R01 HD090161, R01 HD100580, P50 HD012303, R01 AG078185, and NIH R24 HD102061, and a pilot project award from the British Society for Neuroendocrinology. There are no competing interests.

Liraglutide Improves PCOS Symptoms in Rats by Targeting FDX1

BACKGROUND

Polycystic ovary syndrome (PCOS) is a gynecological endocrine disorder characterized by ovulatory disorders, hyperandrogenemia, and polycystic changes in the ovaries. FDX1 is a ferredoxin-reducing protein on human mitochondria that plays an important role in steroid anabolism. Liraglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), has recently emerged as a potential therapeutic agent for PCOS. Recent studies have suggested that FDX1 may be associated with the development of PCOS. This study aims to explore the pivotal role of FDX1 in the amelioration of PCOS through liraglutide intervention.

MATERIALS AND METHODS

A PCOS rat model was induced via subcutaneous DHEA injections. Following successful model establishment, the rats were treated with liraglutide combined with metformin, or with each drug individually, over a six-week period. After 6 weeks of treatment, we assessed changes in body weight, fasting blood glucose, sex hormone levels, estrous cycle regularity, ovarian morphology, FDX1 expression in ovarian tissue, and ovarian ROS levels.

RESULTS

PCOS rats exhibited significant increases in body weight and fasting blood glucose levels, disrupted estrous cycles, and polycystic ovarian morphology. FDX1 expression was notably reduced in the ovarian tissues of PCOS rats. Treatment with liraglutide, both alone and in combination with metformin, led to improvements in body weight, fasting blood glucose, sex hormone balance, estrous cycle regularity, ovarian morphology, and ovarian ROS levels. Notably, FDX1 expression was significantly restored in all treatment groups, with the most substantial increase observed in the liraglutide-treated group.

CONCLUSION

This study suggests that FDX1 could serve as a potential biomarker for elucidating the underlying mechanisms of liraglutide's therapeutic effects in PCOS management.

Apelin receptor modulation mitigates letrozole-induced polycystic ovarian pathogenesis in mice

AIMS

Polycystic ovarian syndrome (PCOS) is one of the most common (about 5-20%) reproductive disorders in women of reproductive age; it is characterized by polycystic ovaries, hyperandrogenism, and oligo/ anovulation. The levels and expression of ovarian adipokines are deregulated in the PCOS. Apelin is an adipokine that acts through its receptor (APJ) and is known to express in the various tissues including the ovary. It has also been suggested that apelin and APJ could be targeted as therapeutic adjuncts for the management of PCOS. However, no study has been conducted on the management of PCOS by targeting the apelin system. Thus, we aimed to evaluate its impact on combating PCOS-associated ovarian pathogenesis.

METHODS

The current work employed a letrozole-induced-hyperandrogenism PCOS-like mice model to investigate the effects of apelin13 and APJ, antagonist ML221. The PCOS model was induced by oral administration of letrozole (1 mg/kg) for 21 days. A total of four experimental groups were made, control, PCOS control, PCOS + aplein13, and PCOS + ML221. The treatment of apelin13 and ML221 was given from day 22 for two weeks.

KEY FINDINGS

The letrozole-induced PCOS-like features such as hyperandrogenism, cystic follicle, decreased corpus luteum, elevated levels of LH/FSH ratio, and up-regulation of ovarian AR expression were ameliorated by apelin13 and ML221 treatment. However, the PCOS-augmented oxidative stress and apoptosis were suppressed by apelin 13 treatments only. ML221 treatment still showed elevated oxidative stress and stimulated apoptosis as reflected by decreased antioxidant enzymes and increased active caspase3 and Bax expression. The expression of ERs was elevated in all groups except control. Furthermore, the PCOS model showed elevated expression of APJ and apelin13 treatment down-regulated its own receptor. Overall, observing the ovarian histology, corpus luteum formation, and decreased androgen levels by both apelin13 and ML221 showed ameliorative effects on the cystic ovary.

SIGNIFICANCE

Despite the similar morphological observation of ovarian histology, apelin13 and ML221 exhibited opposite effects on oxidative stress and apoptosis. Therefore, apelin13 (which down-regulates APJ) and ML221 (an APJ antagonist) may have suppressed APJ signalling, which would account for our findings on the mitigation of polycystic ovarian syndrome. In conclusion, both apelin13 and ML221 mediated mitigation have different mechanisms, which need further investigation.

PPAR-α inhibits DHEA-induced ferroptosis in granulosa cells through upregulation of FADS2

BACKGROUND

Polycystic ovary syndrome (PCOS), a prevalent endocrine disorder among women of reproductive age, is characterized by disturbances in hormone levels and ovarian dysfunction. Ferroptosis, a unique form of regulated cell death characterized by iron-dependent lipid peroxidation. Emerging evidence indicates that ferroptosis may have a significant role in the pathogenesis of PCOS, highlighting the importance of studying this mechanism to better understand the disorder and potentially develop novel therapeutic interventions.

METHODS

To create an in vivo PCOS model, mice were injected with dehydroepiandrosterone (DHEA) and the success of the model was confirmed through further assessments. Ferroptosis levels were evaluated through detecting ferroptosis-related indicators. Ferroptosis-related genes were found through bioinformatic analysis and identified by experiments. An in vitro PCOS model was also established using DHEA treated KGN cells. The molecular binding relationship was confirmed using a chromatin immunoprecipitation (ChIP) assay.

RESULTS

In PCOS model, various ferroptosis-related indicators such as MDA, Fe2+, and lipid ROS showed an increase, while GSH, GPX4, and TFR1 exhibited a decrease. These findings indicate an elevated level of ferroptosis in the PCOS model. The ferroptosis-related gene FADS2 was identified and validated. FADS2 and PPAR-α were shown to be highly expressed in ovarian tissue and primary granulosa cells (GCs) of PCOS mice. Furthermore, the overexpression of both FADS2 and PPAR-α in KGN cells effectively suppressed the DHEA-induced increase in ferroptosis-related indicators (MDA, Fe2+, and lipid ROS) and the decrease in GSH, GPX4, and TFR1 levels. The ferroptosis agonist erastin reversed the suppressive effect, suggesting the involvement of ferroptosis in this process. Additionally, the FADS2 inhibitor SC26196 was found to inhibit the effect of PPAR-α on ferroptosis. Moreover, the binding of PPAR-α to the FADS2 promoter region was predicted and confirmed. This indicates the regulatory relationship between PPAR-α and FADS2 in the context of ferroptosis.

CONCLUSIONS

Our study indicates that PPAR-α may have an inhibitory effect on DHEA-induced ferroptosis in GCs by enhancing the expression of FADS2. This discovery provides valuable insights into the pathophysiology and potential therapeutic targets for PCOS.

High coverage of targeted lipidomics revealed lipid changes in the follicular fluid of patients with insulin-resistant polycystic ovary syndrome and a positive correlation between plasmalogens and oocyte quality

Background

Polycystic ovary syndrome with insulin resistance (PCOS-IR) is the most common endocrine and metabolic disease in women of reproductive age, and low fertility in PCOS patients may be associated with oocyte quality; however, the molecular mechanism through which PCOS-IR affects oocyte quality remains unknown.

Methods

A total of 22 women with PCOS-IR and 23 women without polycystic ovary syndrome (control) who underwent in vitro fertilization and embryo transfer were recruited, and clinical information pertaining to oocyte quality was analyzed. Lipid components of follicular fluid (FF) were detected using high-coverage targeted lipidomics, which identified 344 lipid species belonging to 19 lipid classes. The exact lipid species associated with oocyte quality were identified.

Results

The number (rate) of two pronuclear (2PN) zygotes, the number (rate) of 2PN cleaved embryos, and the number of high-quality embryos were significantly lower in the PCOS-IR group. A total of 19 individual lipid classes and 344 lipid species were identified and quantified. The concentrations of the 19 lipid species in the normal follicular fluid (control) ranged between 10-3 mol/L and 10-9 mol/L. In addition, 39 lipid species were significantly reduced in the PCOS-IR group, among which plasmalogens were positively correlated with oocyte quality.

Conclusions

This study measured the levels of various lipids in follicular fluid, identified a significantly altered lipid profile in the FF of PCOS-IR patients, and established a correlation between poor oocyte quality and plasmalogens in PCOS-IR patients. These findings have contributed to the development of plasmalogen replacement therapy to enhance oocyte quality and have improved culture medium formulations for oocyte in vitro maturation (IVM).

Rhythm gene PER1 mediates ferroptosis and lipid metabolism through SREBF2/ALOX15 axis in polycystic ovary syndrome

OBJECTIVE

This work aimed to investigate the role of rhythm gene PER1 in mediating granulosa cell ferroptosis and lipid metabolism of polycystic ovary syndrome (PCOS).

METHODS

We injected dehydroepiandrosterone and Ferrostatin-1 (Fer-1) into mice to explore the mechanism of ferroptosis in PCOS. The effect of PER1 on ferroptosis-like changes in granulosa cells was explored by overexpression of PER1 plasmid transfection and Fer-1 treatment.

RESULTS

We found that Fer-1 ameliorated the characteristic polycystic ovary morphology, suppressed ferroptosis in the PCOS mice. PER1 and ALOX15 were highly expressed in PCOS, whereas SREBF2 was lowly expressed. Overexpression of PER1 decreased granulosa cell viability and inhibited proliferation. Meanwhile, overexpression of PER1 increased lipid reactive oxygen species, 4-Hydroxynonenal (4-HNE), Malondialdehyde (MDA), total Fe, and Fe2+ levels in granulosa cells and decreased Glutathione (GSH) content. Fer-1, SREBF2 overexpression, or ALOX15 silencing treatment reversed the effects of PER1 overexpression on granulosa cells. PER1 binds to the SREBF2 promoter and represses SREBF2 transcription. SREBF2 binds to the ALOX15 promoter and represses ALOX15 transcription. Correlation analysis of clinical trials showed that PER1 was positively correlated with total cholesterol, low-density lipoprotein cholesterol, luteinizing hormone, testosterone, 4-HNE, MDA, total Fe, Fe2+, and ALOX15. In contrast, PER1 was negatively correlated with SREBF2, high-density lipoprotein cholesterol, follicle-stimulating hormone, progesterone, and GSH.

CONCLUSION

This study demonstrates that the rhythm gene PER1 promotes ferroptosis and dysfunctional lipid metabolism in granulosa cells in PCOS by inhibiting SREBF2/ALOX15 signaling.

Comparative analysis of oral and local intraovarian administration of metformin and nanoparticles (NPs11) in alleviating testosterone-induced polycystic ovary syndrome in rats

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic dysfunction. This study aims to compare the oral and local treatments of metformin or its nanoparticles (NPs11) for ameliorating PCOS in rats. Rats were divided into 4 groups: the control group with no drug treatment; the PCOS group, where subcutaneous testosterone was given (10 mg/kg/day) for 28 days; the MET group, where metformin was administered orally or locally; and the NP group, where metformin NPs11 were also administered orally or locally. Oral administrations were for 21 days, while local injection was performed once surgically. After 7 weeks, all rats were sacrificed; blood glucose and serum hormonal levels and lipid profile were estimated, and the ovaries were assessed by histopathological, Ki-67 immunohistochemical, and histomorphometric evaluations. Blood glucose levels were significantly decreased in groups of orally administered metformin or NPs11 only, while the most efficient option for modulating PCOS-induced hormonal and lipid profile changes was intraovarian injection of NPs11. The ovaries of PCOS rats demonstrated large follicular cysts, massive collagen depositions, and attenuated Ki-67 immunoexpression. Also, the PCOS group revealed a significant decrease in the count of all stages of growing follicles, corpora lutea, granulosa cell layer thickness, and surface area of corpora lutea, in addition to an increase in the number of atretic follicles and follicular cysts, theca cell layer thickness, and surface area of the follicular cysts. All these parameters were recovered with metformin or their NPs11 treatments in different degrees, while local injection of NPs11 was the best option.

Baicalein improves the symptoms of polycystic ovary syndrome by mitigating oxidative stress and ferroptosis in the ovary and gravid placenta

BACKGROUND

Polycystic ovary syndrome is a metabolic and hormonal disorder that is closely linked to oxidative stress. Within individuals diagnosed with PCOS, changes occur in the ovaries, resulting in an excessive buildup of iron and peroxidation of lipids, both of which may be associated with the occurrence of ferroptosis. Baicalein, a flavonoid found in the roots of Scutellaria baicalensis and widely known as Chinese skullcap, is known for its anti-inflammatory and anti-ferroptotic properties, which protect against various diseases. Nevertheless, there has been no investigation into the impact of baicalein on polycystic ovary syndrome.

PURPOSE

This study aimed to correlate ferroptosis with polycystic ovary syndrome and to assess the effects of baicalein on ovarian dysfunction and placental development in pregnant patients.

STUDY DESIGN AND METHODS

Polycystic ovary syndrome was induced in a rat model through the administration of dehydroepiandrosterone, and these rats were treated with baicalein. Oxidative stress and inflammation levels were assessed in serum and ovaries, and tissue samples were collected for histological and protein analyses. Furthermore, different groups of female rats were mated with male rats to observe pregnancy outcomes and tissue samples were obtained for histological, protein, and RNA sequencing. Then, RNA sequencing of the placenta was performed to determine the key genes involved in ferroptosis negative regulation (FNR) signatures.

RESULTS

Baicalein was shown to reduce ovarian oxidative stress and pathology. Baicalein also ameliorated polycystic ovary syndrome by decreasing lipid peroxidation and chronic inflammation and modulating mitochondrial functions and ferroptosis in the ovaries. Specifically, glutathione peroxidase and ferritin heavy chain 1 were considerably downregulated in polycystic ovary syndrome gravid rats compared to their expression in the control group, and most of these differences were reversed after baicalein intervention.

CONCLUSIONS

Our findings, initially, indicated that baicalein could potentially enhance the prognosis of individuals suffering from polycystic ovary syndrome by reducing oxidative stress and ferroptosis, thus potentially influencing the formulation of a therapeutic approach to address this condition.

Advances in the mechanism of metformin with wide-ranging effects on regulation of the intestinal microbiota

Metformin is of great focus because of its high safety, low side effects, and various effects other than lowering blood sugar, such as anti-inflammation, anti-tumor, and anti-aging. Studies have shown that metformin has a modulating effect on the composition and function of the intestinal microbiota other than acting on the liver. However, the composition of microbiota is complex and varies to some extent between species and individuals, and the experimental design of each study is also different. Multiple factors present a major obstacle to better comprehending the effects of metformin on the gut microbiota. This paper reviews the regulatory effects of metformin on the gut microbiota, such as increasing the abundance of genus Akkermansia, enriching short-chain fatty acids (SCFAs)-producing bacterial genus, and regulating gene expression of certain genera. The intestinal microbiota is a large and vital ecosystem in the human body and is considered to be the equivalent of an "organ" of the human body, which is highly relevant to human health and disease status. There are a lot of evidences that the gut microbiota is responsible for metformin's widespread effects. However, there are only a few systematic studies on this mechanism, and the specific mechanism is still unclear. This paper aims to summarize the possible mechanism of metformin in relation to gut microbiota.

Spotlight on iron overload and ferroptosis: Research progress in female infertility

Iron is an essential trace element for organisms. However, iron overload, which is common in haematological disorders (e.g. haemochromatosis, myelodysplastic syndromes, aplastic anaemia, and thalassaemia, blood transfusion-dependent or not), can promote reactive oxygen species generation and induce ferroptosis, a novel form of programmed cell death characterised by excess iron and lipid peroxidation, thus causing cell and tissue damage. Infertility is a global health concern. Recent evidence has indicated the emerging role of iron overload and ferroptosis in female infertility by inducing hypogonadism, causing ovary dysfunction, impairing preimplantation embryos, attenuating endometrial receptivity, and crosstalk between subfertility-related disorders, such as polycystic ovary syndrome and endometriosis. In addition, gut microbiota and their metabolites are involved in iron metabolism, ferroptosis, and female infertility. In this review, we systematically elaborate on the current research progress in female infertility with a novel focus on iron overload and ferroptosis and summarise promising therapies targeting iron overload and ferroptosis to recover fertility in women. In summary, our study provides new insights into female infertility and offers literature references for the clinical management of female infertility associated with iron overload and ferroptosis, which may be beneficial for females with haematopoietic disorders suffering from both iron overload and infertility.

Induced Pluripotent Stem Cells as a Possible Approach for Exploring the Pathophysiology of Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine condition among women with pleiotropic sequelae possessing reproductive, metabolic, and psychological characteristics. Although the exact origin of PCOS is elusive, it is known to be a complex multigenic disorder with a genetic, epigenetic, and environmental background. However, the pathogenesis of PCOS, and the role of genetic variants in increasing the risk of the condition, are still unknown due to the lack of an appropriate study model. Since the debut of induced pluripotent stem cell (iPSC) technology, the ability of reprogrammed somatic cells to self-renew and their potential for multidirectional differentiation have made them excellent tools to study different disease mechanisms. Recently, researchers have succeeded in establishing human in vitro PCOS disease models utilizing iPSC lines from heterogeneous PCOS patient groups (iPSCPCOS). The current review sets out to summarize, for the first time, our current knowledge of the implications and challenges of iPSC technology in comprehending PCOS pathogenesis and tissue-specific disease mechanisms. Additionally, we suggest that the analysis of polygenic risk prediction based on genome-wide association studies (GWAS) could, theoretically, be utilized when creating iPSC lines as an additional research tool to identify women who are genetically susceptible to PCOS. Taken together, iPSCPCOS may provide a new paradigm for the exploration of PCOS tissue-specific disease mechanisms.

Metabolic dysfunction-associated steatotic liver disease: ferroptosis related mechanisms and potential drugs

Metabolic dysfunction-associated steatotic liver disease (MASLD) is considered a "multisystem" disease that simultaneously suffers from metabolic diseases and hepatic steatosis. Some may develop into liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Given the close connection between metabolic diseases and fatty liver, it is urgent to identify drugs that can control metabolic diseases and fatty liver as a whole and delay disease progression. Ferroptosis, characterized by iron overload and lipid peroxidation resulting from abnormal iron metabolism, is a programmed cell death mechanism. It is an important pathogenic mechanism in metabolic diseases or fatty liver, and may become a key direction for improving MASLD. In this article, we have summarized the physiological and pathological mechanisms of iron metabolism and ferroptosis, as well as the connections established between metabolic diseases and fatty liver through ferroptosis. We have also summarized MASLD therapeutic drugs and potential active substances targeting ferroptosis, in order to provide readers with new insights. At the same time, in future clinical trials involving subjects with MASLD (especially with the intervention of the therapeutic drugs), the detection of serum iron metabolism levels and ferroptosis markers in patients should be increased to further explore the efficacy of potential drugs on ferroptosis.

The emerging role of ferroptosis in female reproductive disorders

Iron, as an essential trace element for the organism, is vital for maintaining the organism's health. Excessive iron can promote reactive oxygen species (ROS) accumulation, thus damaging cells and tissues. Ferroptosis is a novel form of programmed cell death distinguished by iron overload and lipid peroxidation, which is unique from autophagy, apoptosis and necrosis, more and more studies are focusing on ferroptosis. Recent evidence suggests that ferroptosis is associated with the development of female reproductive disorders (FRDs), including polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI), endometriosis (EMs), ovarian cancer (OC), preeclampsia (PE) and spontaneous abortion (SA). Pathways and genes associated with ferroptosis may participate in processes that regulate granulosa cell proliferation and secretion, oocyte development, ovarian reserve function, early embryonic development and placental oxidative stress. However, its exact mechanism has not been fully revealed. Therefore, our review systematically elaborates the occurrence mechanism of ferroptosis and its research progress in the development of FRDs, with a view to providing literature references for clinical targeting of ferroptosis -related pathways and regulatory factors for the management of FRDs.

The mechanisms crosstalk and therapeutic opportunities between ferroptosis and ovary diseases

Ferroptosis, a form of regulated cell death, was first defined in 2012. Ferroptosis mainly involves iron-driven lipid peroxidation damage of cells. This process is regulated by iron homeostasis, redox balance, lipid metabolism, glutathione metabolism, and various disease signaling pathways. Iron is one of the key mineral elements that regulate the physiological function of women and the development of ovarian tumors. Occurrence of Ferroptosis has some hidden dangers and advantages in ovary diseases. Some scholars have shown that ferroptosis of ovarian granulosa cells (GC) promotes the development of ovarian dysfunction and polycystic ovary syndrome (PCOS). Interestingly, drug-resistant ovarian cancer cells are very sensitive to ferroptosis, suggesting that pharmacological positive and negative regulation of ferroptosis has great potential in the treatment of benign ovarian diseases and ovarian cancer. This article aimed to assess how ferroptosis occurs and the factors controlling ferroptosis. Moreover, we summarize how ferroptosis can be used to predict, diagnose and target treatment ovary disease. Meanwhile, we also evaluated the different phenomena of Ferroptosis in ovarian diseases. It aims to provide new directions for the research and prevention of female reproductive diseases.

The roles of sirtuins in ferroptosis

Ferroptosis represents a novel non-apoptotic form of regulated cell death that is driven by iron-dependent lipid peroxidation and plays vital roles in various diseases including cardiovascular diseases, neurodegenerative disorders and cancers. Plenty of iron metabolism-related proteins, regulators of lipid peroxidation, and oxidative stress-related molecules are engaged in ferroptosis and can regulate this complex biological process. Sirtuins have broad functional significance and are targets of many drugs in the clinic. Recently, a growing number of studies have revealed that sirtuins can participate in the occurrence of ferroptosis by affecting many aspects such as redox balance, iron metabolism, and lipid metabolism. This article reviewed the studies on the roles of sirtuins in ferroptosis and the related molecular mechanisms, highlighting valuable targets for the prevention and treatment of ferroptosis-associated diseases.

Unveiling Key Biomarkers and Therapeutic Drugs in Polycystic Ovary Syndrome (PCOS) Through Pathway Enrichment Analysis and Hub Gene-miRNA Networks

Background

Polycystic ovary syndrome (PCOS) affects women of reproductive age globally with an incidence rate of 5% - 26%. Growing evidence reports important roles for microRNAs (miRNAs) in the pathophysiology of granulosa cells (GCs) in PCOS.

Objectives

The objectives of this study were to identify the top differentially expressed miRNAs (DE-miRNAs) and their corresponding targets in hub gene-miRNA networks, as well as identify novel DE-miRNAs by analyzing three distinct microarray datasets. Additionally, functional enrichment analysis was performed using bioinformatics approaches. Finally, interactions between the 5 top-ranked hub genes and drugs were investigated.

Methods

Using bioinformatics approaches, three GC profiles from the gene expression omnibus (GEO), namely gene expression omnibus series (GSE)-34526, GSE114419, and GSE137684, were analyzed. Targets of the top DE-miRNAs were predicted using the multiMiR R package, and only miRNAs with validated results were retrieved. Genes that were common between the "DE-miRNA prediction results" and the "existing tissue DE-mRNAs" were designated as differentially expressed genes (DEGs). Gene ontology (GO) and pathway enrichment analyses were implemented for DEGs. In order to identify hub genes and hub DE-miRNAs, the protein-protein interaction (PPI) network and miRNA-mRNA interaction network were constructed using Cytoscape software. The drug-gene interaction database (DGIdb) database was utilized to identify interactions between the top-ranked hub genes and drugs.

Results

Out of the top 20 DE-miRNAs that were retrieved from the GSE114419 and GSE34526 microarray datasets, only 13 of them had "validated results" through the multiMiR prediction method. Among the 13 DE-miRNAs investigated, only 5, namely hsa-miR-8085, hsa-miR-548w, hsa-miR-612, hsa-miR-1470, and hsa-miR-644a, demonstrated interactions with the 10 hub genes in the hub gene-miRNA networks in our study. Except for hsa-miR-612, the other 4 DE-miRNAs, including hsa-miR-8085, hsa-miR-548w, hsa-miR-1470, and hsa-miR-644a, are novel and had not been reported in PCOS pathogenesis before. Also, GO and pathway enrichment analyses identified "pathogenic E. coli infection" in the Kyoto encyclopedia of genes and genomes (KEGG) and "regulation of Rac1 activity" in FunRich as the top pathways. The drug-hub gene interaction network identified ACTB, JUN, PTEN, KRAS, and MAPK1 as potential targets to treat PCOS with therapeutic drugs.

Conclusions

The findings from this study might assist researchers in uncovering new biomarkers and potential therapeutic drug targets in PCOS treatment.