Derailed peripheral circadian genes in polycystic ovary syndrome patients alters peripheral conversion of androgens synthesis

Circadian rhythm disruption and polycystic ovary syndrome: a systematic review and meta-analysis

Objective

The aim of our systematic review and meta-analysis was to determine if circadian rhythm disruption (CRD) is associated with polycystic ovary syndrome (PCOS). Our objective was to pool the overall mean differences in biomarkers of CRD (including melatonin levels, morning and evening cortisol levels, and sleep efficiency) between PCOS patients and controls. We hypothesized that CRD will be more prominent in patients with PCOS.

Data sources

A systematic search of PubMed, Scopus, Embase, ClinicalTrials.Gov, and the Cochrane Database of Systematic Reviews was conducted from inception until 2024 using the following MeSH terms "circadian rhythm" OR "sleep disturbance" OR "melatonin" AND "polycystic ovary syndrome." Citation search supplemented the systematic database search.

Study eligibility criteria

Inclusion criteria were women with PCOS, original case-control, cross-sectional, and cohort studies that identify parameters of CRD (melatonin, cortisol, and sleep disturbance). Exclusion criteria were women with endocrine and metabolic co-morbidities, menopausal women, case reports, review studies, animal studies, abstracts, and conference presentations. There was no time restriction for year of publication.

Study appraisal and synthesis methods

Two investigators (T.H. and P.R.) assessed the quality of the studies included using the Newcastle-Ottawa Scale. Forest plots were created using the Open Meta Analyst software. Publication bias was assessed in Egger's and Begg's tests.

Results

A total of 16 studies were included in the systematic review and 12 studies were included in the meta-analysis (N=1,100 women [531 PCOS patients and 569 controls]). Pooled analysis showed that the mean difference in melatonin levels between PCOS patients and controls was 14.294 pg/mL, 95% CI [6.895, 21.693]. The overall mean difference in morning and evening cortisol between PCOS patients and controls was 1.103 pg/mL, 95% CI [-1.058, 3.265], and 3.574 pg/mL, 95% CI [1.741, 5.407], respectively. Pooled difference in mean sleep efficiency scores between PCOS patients and controls was -4.059, 95% CI [-6.752, -1.366]. Risk of bias assessment showed that NOS scores ranged from 7 to 9.

Conclusions

Our meta-analysis provides evidence that circadian rhythm disruption is positively associated with polycystic ovary syndrome. This is substantiated by differences in parameters indicative of circadian rhythm disruption, including melatonin levels, evening cortisol, and sleep efficiency.

Melatonin refines ovarian mitochondrial dysfunction in PCOS by regulating the circadian rhythm gene Clock

Mitochondrial dysfunction is present in the ovaries of patients with polycystic ovary syndrome (PCOS). Melatonin (MT) has shown promise in treating PCOS by improving mitochondrial dysfunction, though the underlying mechanisms remain unclear. In this study, we first assessed the levels of proteins associated with mitochondrial autophagy and dynamics in ovary granulosa cells (GCs) of PCOS patients and in the ovaries of DHEA-induced PCOS mice. We found abnormal expression of these proteins, indicating the presence of mitochondrial dysfunction in PCOS ovaries. Notably, the expression of the circadian gene Clock and melatonin synthetic enzymes were also decreased in the ovaries of PCOS patients. Studies have suggested a potential role of circadian rhythm genes in the pathogenesis and progression of PCOS. We subsequently observed that pretreatment with MT could ameliorate the abnormal levels of mitochondrial-related proteins, reverse the low expression of CLOCK, and reduce pyroptosis in PCOS ovaries. Given the potential interaction between MT and Clock, we focused on whether exogenous MT improves mitochondrial dysfunction in PCOS ovaries by regulating the expression of the circadian gene Clock. Through in vitro culture of the human ovarian granulosa cell line KGN, we further found that when CLOCK levels were inhibited, the beneficial effects of MT on abnormal mitochondrial autophagy, disturbed mitochondrial dynamics, and mitochondrial dysfunction in PCOS ovaries were not significant, and there was no notable improvement in ovary GCs pyroptosis. Our study suggests that MT may improve ovary mitochondrial dysfunction by regulating circadian gene Clock while also reducing GCs pyroptosis in PCOS.

BMAL1 improves assisted reproductive technology outcomes in patients with polycystic ovary syndrome by targeting BMP6 and regulating ovarian granulosa cell apoptosis

PURPOSE

To investigate BMAL1 and BMP6 expressive differences in ovarian granulosa cells (OGCs) of patients with polycystic ovary syndrome (PCOS), explore regulatory relationship, assess their impacts on OGC proliferation and apoptosis, and analyze their correlations with ART outcomes of patients.

METHODS

A clinical study selected 40 PCOS patients who underwent IVF/ICSI in our hospital from January to October 2022 and 39 controls with male or tubal factor infertility. RT-qPCR and Western blot assessed BMAL1 and BMP6 mRNA/protein levels. The number of oocytes retrieved, 2PN fertilized oocytes, available embryos, and high-quality embryos were compared between groups and analyzed their correlations with BMAL1 and BMP6 expression levels. Cellular experiments were performed by overexpressing or knocking down BMAL1 in KGN cells by plasmid transfection. The dual-luciferase reporter assay was used to identify BMAL1/BMP6 regulatory relationship. CCK-8 and flow cytometry assessed cellular proliferation and apoptosis.

RESULTS

BMAL1 mRNA/protein expression (P < 0.001) in the PCOS group was significantly lower than that in controls, as was the number of high-quality embryos (P = 0.001). Contrastingly, BMP6 (P < 0.001) was significantly higher in the PCOS group. BMAL1 expression levels were negatively correlated with BMP6 (r = - 0.684, P = 0.002) and positively correlated with the number of 2PN fertilized oocytes, available embryos, and high-quality embryos (r = 0.659, P = 0.003; r = 0.623, P = 0.006; and r = 0.738, P < 0.001). Cellular experiments showed that overexpression of BMAL1 significantly decreased relative luciferase activity (P < 0.01). Overexpression of BMAL1 significantly decreased KGN cell apoptosis (P < 0.01) and enhanced proliferation (P < 0.01).

CONCLUSION

BMAL1 regulates OGCs proliferation and apoptosis by targeting BMP6, thereby influencing ART outcomes in patients with PCOS. This study might provide molecular factors that indicate ART outcomes and therapeutic targets for PCOS.

TRIAL REGISTRATION

Registration number: ChiCTR2100052331; registration date: 2021-10-24.

Characteristics of polycystic ovary syndrome rat models induced by letrozole, testosterone propionate and high-fat diets

RESEARCH QUESTION

What are the long-term effects of different models of polycystic ovary syndrome (PCOS), and which model could be used in future research?

DESIGN

PCOS models induced by letrozole, letrozole plus high-fat diet (LE+HFD), testosterone propionate (TP) or testosterone propionate plus HFD (TP+HFD) were established in rats. Body weight, energy intake, blood glucose, sex hormone concentrations, lipid profiles and the oestrus cycle were observed. Histology of ovaries, large intestine and fat was displayed. Protein and mRNA levels relating to hormone synthesis, oocyte maturation, the gut barrier, lipid metabolism and inflammation were evaluated using western blotting, immunohistochemistry and PCR. The composition of the microbial community was measured using 16S RNA sequencing.

RESULTS

Letrozole treatment induced hyperandrogenaemia, polycystic ovarian morphology, a disrupted oestrus cycle and impaired ovarian function, which could be restored within 42 days. Concurrently, letrozole disturbed glucose, fat, and energy metabolism, affected the inflammatory state and compromised intestinal homeostasis. HFD could amplify the disturbances in the metabolism and intestinal microenvironment, and the pituitary-ovarian axis was more efficiently and consistently affected by testosterone propionate. Testosterone propionate and TP+HFD treatment also disturbed the intestinal microenvironment. Although the metabolic effects of testosterone propionate were not as profound as those of letrozole, they were enhanced by HFD.

CONCLUSIONS

Letrozole is useful for studies on metabolic disturbances in PCOS, and LE+HFD treatment is suitable for investigations on PCOS metabolic abnormalities and the gut-PCOS link. Testosterone propionate injection is appropriate for studying reproductive abnormalities in PCOS, while TP+HFD treatment is the most comprehensive for studying PCOS reproductive abnormalities, metabolic disturbances and the gut-PCOS link.

The circadian rhythm: A key variable in aging?

The determination of age-related transcriptional changes may contribute to the understanding of health and life expectancy. The broad application of results from age cohorts may have limitations. Altering sample sizes per time point or sex, using a single mouse strain or tissue, a limited number of replicates, or omitting the middle of life can bias the surveys. To achieve higher general validity and to identify less distinctive players, bulk RNA sequencing of a mouse cohort, including seven organs of two strains from both sexes of 5 ages, was performed. Machine learning by bootstrapped variable importance and selection methodology (Boruta) was used to identify common aging features where the circadian rhythms (CiR) transcripts appear as promising age markers in an unsupervised analysis. Pathways of 11 numerically analyzed local network clusters were affected and classified into four major gene expression profiles, whereby CiR and proteostasis candidates were particularly conspicuous with partially opposing changes. In a data-based interaction association network, the CiR-proteostasis axis occupies an exposed central position, highlighting its relevance. The computation of 11,830 individual transcript associations provides potential superordinate contributors, such as hormones, to age-related changes, as in CiR. In hormone-sensitive LNCaP cells, short-term supraphysiologic levels of the sex hormones dihydrotestosterone or estradiol increase the expression of the CiR transcript Bhlhe40 and the associated senescence regulator Cdkn2b (p15). According to these findings, the bilateral dysregulation of CiR appears as a fundamental protagonist of aging, whose transcripts could serve as a biological marker and its restoration as a therapeutic opportunity.

Polycystic ovary syndrome in obstructive sleep apnea-hypopnea syndrome: an updated meta-analysis

Background

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is correlated with metabolic deterioration in patients experiencing polycystic ovary syndrome (PCOS). Women diagnosed with PCOS exhibit a heightened prevalence of OSAHS. This meta-analysis aims to assess the morbidity of OSAHS in women affected by PCOS and to examine the differences in metabolism-related indicators between OSAHS-positive and OSAHS-negative in women with PCOS.

Methods

A comprehensive literature analysis of OSAHS morbidity in women with PCOS was conducted, utilizing databases such as CNKI, EMBASE, PubMed, Web of Science, and Wanfang. A comparison was carried out between patients with OSAHS-positive and those with OSAHS-negative in terms of their clinical characteristics and metabolic differences. The search language included English and Chinese. The acquired data were analyzed by employing RevMan 5.2 and Stata 11.0. Continuous variables with the same units were combined and analyzed through weighted mean differences (WMDs) as effect sizes, while continuous variables with different units were combined and analyzed through standardized mean differences (SMDs) as effect sizes. A conjoint analysis was performed on the basis of I2 value, using either a fixed effect model (I2 ≤ 50%) or a random effect model (I2 > 50%).

Results

A total of 21 articles met the inclusion criteria for this study. The findings indicated that 20.8% of women with PCOS were found to have comorbid OSAHS. The subjects were categorized into various subgroups for meta-analysis on the basis of race, age, disease severity, body mass index (BMI), and diagnostic criteria of PCOS. The results revealed high morbidity of OSAHS in all subgroups. In addition, most metabolic indicators and parameters of metabolic syndrome were notably worse in women suffering from both PCOS and OSAHS in comparison to their counterparts solely diagnosed with PCOS.

Conclusion

The current literature indicates higher morbidity of OSAHS among women with PCOS, linking OSAHS with worse metabolic status and obesity in this population. Consequently, clinicians are advised to prioritize the detection and management of OSAHS in women with PCOS.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/#myprospero PROSPERO, identifier (CRD42024528264).

Bmal1 regulates female reproduction in mice via the hypothalamic-pituitary-ovarian axis

The hypothalamic-pituitary-gonadal axis (HPG) is the key neuroendocrine axis involved in reproductive regulation. Brain and muscle ARNT-like protein 1 (Bmal1) participates in regulating the metabolism of various endocrine hormones. However, the regulation of Bmal1 on HPG and female fertility is unclear. This study aims to explore the regulation of female reproduction by Bmal1 via the HPG axis in mice. Bmal1-knockout (Ko) mice were generated using the CRISPR/Cas9 technology. The structure, function, and estrous cycle of ovarian in Bmal1 Ko female mice were measured. The key genes and proteins of the HPG axis involved in regulating female reproduction were examined through transcriptome analysis and then verified by RT-PCR, immunohistochemistry, and western blot. Furthermore, the fertility of female mice was detected after intervening prolactin (PRL) and progesterone (Pg) in Bmal1 ko mice. The number of offspring and ovarian weight were significantly lower in Bmal1-Ko mice than in wild-type (Wt) mice. In Bmal1-Ko mice, ovarian cells were arranged loosely and irregularly, and the total number of follicles was significantly reduced. No corpus luteum was found in the ovaries. Vaginal smears revealed that Bmal1-Ko mice had an irregular estrus cycle. In Bmal1-Ko mice, Star expression was decreased, PRL and luteinizing hormone (LH) levels were increased, and dopamine (DA) and Pg levels were decreased. Inhibition of PRL partially recovered the estrous cycle, corpus luteum formation, and Star expression in the ovaries. Pg supplementation promoted embryo implantation in Bmal1-Ko female mice. Bmal1 Ko increases serum PRL levels in female mice likely by reducing DA levels, thus affecting luteal formation, resulting in decreased Star expression and Pg production, hindering female reproduction. Inhibition of PRL or restoration of Pg can partially restore reproductive capacity in female Bmal1-Ko mice. Thus, Bmal1 may regulate female reproduction via the HPG axis in mice, suggesting that Bmal1 is a potential target to treat female infertility.

Outdoor Artificial Light at Night and Reproductive Endocrine and Glucose Homeostasis and Polycystic Ovary Syndrome in Women of Reproductive Age

BACKGROUND

Artificial light at night, a well-recognized circadian clock disrupter, causes disturbances in endocrine homeostasis. However, the association of artificial light at night with polycystic ovary syndrome (PCOS) is still unknown. This study examines the effects of outdoor artificial light at night on sex hormones, glucose homeostasis markers, and PCOS prevalence in Anhui Province, China.

METHODS

We recruited 20,633 women of reproductive age from Anhui Medical University Reproductive Medicine Center. PCOS was diagnosed according to Rotterdam criteria. We estimated long-term (previous year) and short-term (previous month) artificial light at night values for residential addresses using 500 m resolution satellite imagery. We fitted multivariable models, using both linear and logistic regression, to estimate the association of artificial light at night with sex hormones, glucose homeostasis markers, and PCOS prevalence.

RESULTS

Both long-term and short-term exposure to outdoor artificial light at night were negatively associated with follicle-stimulating hormone and luteinizing hormone levels, while positively associated with testosterone, fasting insulin, homeostasis model assessment-insulin resistance, and homeostasis model assessment-insulin resistance-β levels. The second-highest quintile of artificial light at night was associated with increased PCOS prevalence (odds ratio [OR long-term ] = 1.4; 95% confidence interval [CI] = 1.2, 1.6 and OR short-term = 1.3; 95% CI = 1.1, 1.5) compared with the lowest quintile. In addition, prevalence of PCOS was linearly associated with long-term exposure to artificial light at night, but nonlinearly associated with short-term exposure. This association was more evident in younger, obese or overweight, moderately educated, rural women, and for the summer and fall seasons.

CONCLUSION

Outdoor artificial light at night may be a novel risk factor for PCOS.

Epigenetic/circadian clocks and PCOS

Polycystic ovary syndrome (PCOS) affects 6-20% of reproductive-aged women. It is associated with increased risks of metabolic syndrome, Type 2 diabetes, cardiovascular diseases, mood disorders, endometrial cancer and non-alcoholic fatty liver disease. Although various susceptibility loci have been identified through genetic studies, they account for ∼10% of PCOS heritability. Therefore, the etiology of PCOS remains unclear. This review explores the role of epigenetic changes and modifications in circadian clock genes as potential contributors to PCOS pathogenesis. Epigenetic alterations, such as DNA methylation, histone modifications, and non-coding RNA changes, have been described in diseases related to PCOS, such as diabetes, cardiovascular diseases, and obesity. Furthermore, several animal models have illustrated a link between prenatal exposure to androgens or anti-Müllerian hormone and PCOS-like phenotypes in subsequent generations, illustrating an epigenetic programming in PCOS. In humans, epigenetic changes have been reported in peripheral blood mononuclear cells (PBMC), adipose tissue, granulosa cells (GC), and liver from women with PCOS. The genome of women with PCOS is globally hypomethylated compared to healthy controls. However, specific hypomethylated or hypermethylated genes have been reported in the different tissues of these women. They are mainly involved in hormonal regulation and inflammatory pathways, as well as lipid and glucose metabolism. Additionally, sleep disorders are present in women with PCOS and disruptions in clock genes' expression patterns have been observed in their PBMC or GCs. While epigenetic changes hold promise as diagnostic biomarkers, the current challenge lies in distinguishing whether these changes are causes or consequences of PCOS. Targeting epigenetic modifications potentially opens avenues for precision medicine in PCOS, including lifestyle interventions and drug therapies. However, data are still lacking in large cohorts of well-characterized PCOS phenotypes. In conclusion, understanding the interplay between genetics, epigenetics, and circadian rhythms may provide valuable insights for early diagnosis and therapeutic strategies in PCOS in the future.

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.

Androgen excess: a hallmark of polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a metabolic, reproductive, and psychological disorder affecting 6-20% of reproductive women worldwide. However, there is still no cure for PCOS, and current treatments primarily alleviate its symptoms due to a poor understanding of its etiology. Compelling evidence suggests that hyperandrogenism is not just a primary feature of PCOS. Instead, it may be a causative factor for this condition. Thus, figuring out the mechanisms of androgen synthesis, conversion, and metabolism is relatively important. Traditionally, studies of androgen excess have largely focused on classical androgen, but in recent years, adrenal-derived 11-oxygenated androgen has also garnered interest. Herein, this Review aims to investigate the origins of androgen excess, androgen synthesis, how androgen receptor (AR) signaling mediates adverse PCOS traits, and the role of 11-oxygenated androgen in the pathophysiology of PCOS. In addition, it provides therapeutic strategies targeting hyperandrogenism in PCOS.

Population Dynamics, Plasma Cytokines and Platelet Centrifugation: Technical and Sociodemographic Aspects of 'Ovarian Rejuvenation'

While advanced reproductive technologies have attained remarkable increases in sophistication, success, and availability since the 1980s, clinicians always meet a therapeutic impasse when the ovarian reserve reaches exhaustion. Irrespective of fertility aspirations, the decline in and eventual collapse of ovarian estrogen output means that menopause arrives with tremendous physiologic changes and reduced overall productivity. Because more women are gaining in longevity or delaying the age at pregnancy, the number of affected patients has never been larger. As concerns regarding standard hormone replacement therapy and the limitations of IVF are confronted, a workable path to enable primordial germ cell recruitment and de novo oocyte development would be welcome. Proof-of-concept case reports and clinical studies on autologous activated platelet-rich plasma (PRP) or its condensed cytokine derivatives suggest a way to facilitate these goals. However, ovarian PRP faces vexing challenges that place 'ovarian rejuvenation' under caution as it enters this therapeutic space. Here, we review key features of experimental human ovarian stem cell isolation/handling and reaffirm the need to harmonize laboratory protocols. Recognizing the regenerative science borrowed from other disciplines, specimen centrifugation, platelet processing, and condensed plasma cytokine enrichment are highlighted here. As the refinement of this rejuvenation approach would promise to reprogram adult ovarian physiology, the disruption of established treatment paradigms for infertility, menopause, and perhaps overall women's health seems likely. Emerging roles in reproductive biology and clinical practice are thus placed in a broader social and demographic context.

Endocrine Disrupting Chemicals in Polycystic Ovary Syndrome: The Relevant Role of the Theca and Granulosa Cells in the Pathogenesis of the Ovarian Dysfunction

Polycystic ovary syndrome (PCOS) is the most common heterogeneous endocrine disorder among women of reproductive age. The pathogenesis of PCOS remains elusive; however, there is evidence suggesting the potential contribution of genetic interactions or predispositions combined with environmental factors. Among these, endocrine disrupting chemicals (EDCs) have been proposed to potentially contribute to the etiology of PCOS. Granulosa and theca cells are known to cooperate to maintain ovarian function, and any disturbance can lead to endocrine disorders, such as PCOS. This article provides a review of the recent knowledge on PCOS pathophysiology, the role of granulosa and theca cells in PCOS pathogenesis, and the evidence linking exposure to EDCs with reproductive disorders such as PCOS.

Acute hypoxia induced dysregulation of clock-controlled ovary functions

High altitudes or exposure to hypoxia leads to female reproductive disorders. Circadian clocks are intrinsic time-tracking systems that enable organisms to adapt to the Earth's 24-h light/dark cycle, which can be entrained by other environmental stimuli to regulate physiological and pathological responses. In this study, we focused on whether ovarian circadian clock proteins were involved in regulating female reproductive dysfunction under hypoxic conditions. Hypobaric hypoxia was found to induce a significantly prolonged estrous cycle in female mice, accompanied by follicular atresia, pituitary/ovarian hormone synthesis disorder, and decreased LHCGR expression in the ovaries. Under the same conditions, the levels of the ovarian circadian clock proteins, CLOCK and BMAL1, were suppressed, whereas E4BP4 levels were upregulated. Results from granulosa cells (GCs) further demonstrated that CLOCK: BMAL1 and E4BP4 function as transcriptional activators and repressors of LHCGR in ovarian GCs, respectively, whose responses were mediated by HIF1ɑ-dependent (E4BP4 upregulation) and ɑ-independent (CLOCK and BMAL1 downregulation) manners. The LHCGR agonist was shown to efficiently recover the impairment of ovulation-related gene (EREG and PGR) expression in GCs induced by hypoxia. We conclude that hypoxia exposure causes dysregulation of ovarian circadian clock protein (CLOCK, BMAL1, and E4BP4) expression, which mediates female reproductive dysfunction by impairing LHCGR-dependent signaling events. Adjusting the timing system or recovering the LHCGR level in the ovaries may be helpful in overcoming female reproductive disorders occurring in the highlands.

Physiological regulation of leptin as an integrative signal of reproductive readiness

Reproductive function is tightly regulated by both environmental and physiological factors. The adipose-derived hormone leptin has been identified as one such critical factor that relays information about peripheral energy availability to the centrally-governed HPG axis to ensure there is sufficient energy availability to support the high energy demands of mammalian reproduction. In the absence of adequate central leptin signaling, reproductive function is suppressed. While leptin levels are predominantly regulated by adiposity, circulating leptin levels are also under the modulatory influence of other factors, such as stress system activation, circadian rhythmicity, and immune activation and the inflammatory response. Furthermore, changes in leptin sensitivity can affect the degree to which leptin exerts its influence on the neuroendocrine reproductive axis. This review will discuss the different mechanisms by which leptin serves to integrate and relay information about metabolic, psychological, environmental and immune conditions to the central neuronal network that governs reproductive function.

Therapeutic potential of exosomes/miRNAs in polycystic ovary syndrome induced by the alteration of circadian rhythms

Polycystic ovary syndrome (PCOS) is a reproductive dysfunction associated with endocrine disorders and is most common in women of reproductive age. Clinical and/or biochemical manifestations include hyperandrogenism, persistent anovulation, polycystic ovary, insulin resistance, and obesity. Presently, the aetiology and pathogenesis of PCOS remain unclear. In recent years, the role of circadian rhythm changes in PCOS has garnered considerable attention. Changes in circadian rhythm can trigger PCOS through mechanisms such as oxidative stress and inflammation; however, the specific mechanisms are unclear. Exosomes are vesicles with sizes ranging from 30-120nm that mediate intercellular communication by transporting microRNAs (miRNAs), proteins, mRNAs, DNA, or lipids to target cells and are widely involved in the regulation of various physiological and pathological processes. Circadian rhythm can alter circulating exosomes, leading to a series of related changes and physiological dysfunctions. Therefore, we speculate that circadian rhythm-induced changes in circulating exosomes may be involved in PCOS pathogenesis. In this review, we summarize the possible roles of exosomes and their derived microRNAs in the occurrence and development of PCOS and discuss their possible mechanisms, providing insights into the potential role of exosomes for PCOS treatment.