Vitamin D3 regulates steroidogenesis in granulosa cells through AMP-activated protein kinase (AMPK) activation in a mouse model of polycystic ovary syndrome

Role of the AMP-Activated Protein Kinase in the Pathogenesis of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a complex disorder characterized by elevated androgen levels, menstrual irregularities, and polycystic morphology of the ovaries. Affecting 6-10% of women in childbearing age, PCOS is a leading cause of infertility worldwide. In recent years, there has been a growing acknowledgment of the involvement of adenosine monophosphate-activated protein kinase (AMPK) in the development of polycystic ovary syndrome (PCOS). The expression of AMPK is diminished in polycystic ovaries, and when AMPK is silenced in human granulosa cells, there is a rise in the expression of steroidogenic enzymes, resulting in increased production of estradiol and progesterone. Additionally, in mouse models, the inhibiting AMPK intensifies the polycystic appearance of ovaries and impairs the process of ovulation. Moreover, it has been shown that AMPK activators like metformin and resveratrol ameliorate PCOS associated signs and symptoms in experimental and clinical studies. These findings, collectively, indicate the key role of AMPK in the pathogenesis of PCOS. Understanding the role of AMPK in PCOS will offer rewarding information on details of PCOS pathogenesis and will provide novel more specific therapeutic approaches. The present review summarizes the latest findings regarding the role of AMPK in PCOS obtained in experimental and clinical studies.

Vitamin D status alters genes involved in ovarian steroidogenesis in muskrat granulosa cells

This study aims to explore the relationship between altered vitamin D (VitD3) status and ovarian steroidogenesis in muskrats during the breeding and non-breeding seasons. During the breeding season, the ovaries of muskrats were observably enlarged and increased in weight, accompanied by elevated serum and ovarian VitD3 status. Vitamin D receptor (VDR), VitD3 metabolic molecules (CYP2R1, CYP27B1, and CYP24A1), and steroidogenic enzymes were immunolocalized in the ovarian cells of muskrats. The mRNA levels of VDR, CYP2R1, CYP27B1, and steroidogenic enzymes were considerably higher during the breeding season compared to the non-breeding season. RNA-seq analysis revealed a prominent enrichment of vitamin-related and ovarian steroidogenesis pathways. Furthermore, the addition of 1,25(OH)2D3 to the muskrat granulosa cells in vitro increased VDR and steroidogenic enzymes mRNA levels and enhanced the 17β-estradiol level. Overall, these findings supported that VitD3 promotes the secretion of steroid hormones, thereby affecting seasonal changes in ovarian function in the muskrats.

Seasonal changes of vitamin D3 and ovarian steroidogenesis in the wild ground squirrels (Citellus dauricus Brandt)

There is mounting evidence that vitamin D3 regulates female reproductive function critically, while little is known about the function of seasonally variable vitamin D3 in regulating ovarian steroidogenesis. This study examined the seasonal expressions of vitamin D receptor (VDR), vitamin D metabolic molecules (CYP2R1, CYP27B1, and CYP24A1), and steroidogenic enzymes (P450scc, 3β-HSD, P450c17, and P450arom) in the ovaries of the wild ground squirrels (Citellus dauricus Brandt) during the different breeding seasons. VDR, CYP2R1, CYP27B1, and CYP24A1 were shown to be localized in different types of ovarian cells in the wild ground squirrels during the breeding and non-breeding seasons. Meanwhile, the mRNA levels of VDR, CYP2R1, CYP27B1, CYP11A1, HSD3B1, CYP17A1, and CYP19A1 in the ovaries were remarkably higher in the breeding season. Furthermore, RNA-seq data of ovaries revealed that 6036 genes were differentially expressed genes (DEGs); further analysis revealed that several DEGs known to be involved in ovarian steroidogenesis pathway and cellular response to vitamin D pathway were identified. In addition, during the breeding season, the concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone, and 17β-estradiol were greater in the serum of the wild female ground squirrels. This observation was positively correlated with seasonal changes in the concentration of 25(OH)D3, supporting the fact that the 25(OH)D3 content in the ovaries was significantly higher in the breeding season. These findings suggested that seasonal changes in vitamin D3 might regulate the ovarian steroidogenesis of the wild female ground squirrels.

Synthesis, Regulatory Factors, and Signaling Pathways of Estrogen in the Ovary

New insights have been thrown for understanding the significant role of estrogen on various systems of humans. Increasing evidences have determined the significant roles of estrogen in female reproductive system. So, the normal synthesis and secretion of estrogen play important roles in maintaining the function of tissues and organs. The ovaries are the main synthetic organs of estrogen. In this review, we summarized the current knowledge of the estrogen synthesis in the ovaries. A series of factors and signaling pathways that regulate the synthesis of estrogen are expounded in detail. Understanding the regulating factors and potential mechanism related to estrogen synthesis will be beneficial for understanding estrogen disorder related diseases and may provide novel therapeutic targets.

Polycystic ovary syndrome and obesity: a modern paradigm

Polycystic ovary syndrome is a heterogeneous endocrine disease that affects women of childbearing age. The pathogenesis of polycystic ovary syndrome has not been fully studied to date, its paradigm considers the genetic determinism of the manifestation of hormonal and metabolic disorders, which are considered to be criteria for the verification of the disease (hyperandrogenism, oligo/anovulation and/or polycystic ovarian transformation during ultrasound examination (ultrasound). This review discusses the main ways of interaction between hyperandrogenism, insulin resistance and obesity and their role in the pathogenesis of polycystic ovary syndrome, as well as possible methods of treatment for this category of patients. The review analyzes the role of hyperandrogenism and insulin resistance in the implementation of the genetic scenario of polycystic ovary syndrome and finds out the reasons why women with polycystic ovary syndrome often demonstrate the presence of a «metabolic trio» - hyperinsulinemia, insulin resistance and type 2 diabetes mellitus. It is noted that obesity is not included in the criteria for the diagnosis of polycystic ovary syndrome, but epidemiological data confirm the existence of a relationship between these diseases. Obesity, especially visceral, which is often found in women with polycystic ovary syndrome, enhances and worsens metabolic and reproductive outcomes with polycystic ovary syndrome, as well as increases insulin resistance and compensatory hyperinsulinemia, which, in turn, stimulates adipogenesis and suppresses lipolysis. Obesity increases the sensitivity of tech cells to luteinizing hormone stimulation and enhances functional hyperandrogenism of the ovaries, increasing the production of androgens by the ovaries. Excess body weight is associated with a large number of inflammatory adipokines, which, in turn, contribute to the growth of insulin resistance and adipogenesis. Obesity and insulin resistance exacerbate the symptoms of hyperandrogenism, forming a vicious circle that contributes to the development of polycystic ovary syndrome. These data allow us to conclude that bariatric surgery can become an alternative to drugs (metformin, thiazolidinedione analogs of glucagon-like peptide-1), which has shown positive results in the treatment of patients with polycystic ovary syndrome and obesity.

A bibliometric analysis of global research on vitamin D and reproductive health between 2012 and 2021: Learning from the past, planning for the future

Background

Vitamin D plays an invaluable role in reproductive health, but vitamin D insufficiency and deficiency are generally common among couples of childbearing age and pregnant women. This study aimed to evaluate the evolution, development trend, and research hotspot of publications on vitamin D and reproductive health.

Methods

The literature on vitamin D and reproductive health between 2012 and 2021 was retrieved from the Web of Science Core Collection (WoSCC). We used VOSviewer and CiteSpace to analyze publication years, countries, institutions, journals, highly cited authors and publications, and co-occurrence and citation bursts of keywords.

Results

A total of 1,828 articles and reviews on vitamin D and reproductive health published between 2012 and 2021 were identified. The annual publication outputs showed steady growth, with the most publications (272) and citations (7,097) in 2021. The United States contributed the most publications (458) and had the highest h-index (58). In terms of the number of publications and h-index, the journal named Nutrients ranked first. Nutrition dietetics, obstetrics gynecology, and endocrinology metabolism were three well-represented disciplines in research on vitamin D and reproductive health. Hollis BW, Wagner CL, and Litonjua AA were the top three most productive authors in this field during the last decade. Apart from vitamin D, the five keywords with the most frequent occurrence were vitamin D deficiency, pregnancy, risk, vitamin D supplementation, and 25-hydroxyvitamin D. Keyword citation burst analysis revealed that low birth weight, adipose tissue, marker, and embryo had a citation burst lasting until 2021.

Conclusion

In conclusion, vitamin D has received continuous attention in the field of reproductive health, and there appears to have a higher level of research in North America. Multidisciplinary intersection contributed to the in-depth exploration in this field. And the effect of maternal vitamin D levels on fetal lipid metabolism and the prediction of fertility by vitamin D-related markers might be hotspots for the research.

Association of Insulin Resistance and Elevated Androgen Levels with Polycystic Ovarian Syndrome (PCOS): A Review of Literature

The polycystic ovary syndrome (PCOS) is the disease featured by elevated levels of androgens, ovulatory dysfunction, and morphological abnormalities. At reproductive stage of women, the rate of PCOS occurrence is measured as 6–10% and the prevalence rate may be double. There are different pathophysiological factors involved in PCOS, and they play a major role in various abnormalities in individual patient. It is clear that there is noteworthy elevation of androgen in PCOS, causing substantial misery and infertility problems. The overexposure of androgen is directly linked with insulin resistance and hyperinsulinaemia. It has been reported previously that PCOS is related to cardiac metabolic miseries and potently increases the risk of heart diseases. Endometrial cancer is also a serious concern which is reported with exceedingly high incidence in women with PCOS. However, the overexposure of androgen has direct and specific influence on the development of insulin resistance. Although many factors are involved, resistance to the insulin and enhanced level of androgen are considered the major causes of PCOS. In the present review, we have focused on the pathophysiology and major revolutions of insulin resistance and excessive levels of androgen in females with PCOS.

Expression profile analysis of sheep ovary after superovulation and estrus synchronisation treatment

Superovulation is a widely used reproductive technique in livestock production, but the mechanism of sheep's superovulation is not yet clear. Here, a method of superovulation and estrus synchronisation was used to treat female Duolang sheep. After treatment, there were significant differences in serum FSH and LH levels and the number of dominant follicles between the two groups of sheep. We identified a total of 5021 differentially expressed genes (11, 13 and 15 days after treatment) and performed RT‐qPCR analysis to identify several mRNA expression levels. GO and KEGG enrichment analysis revealed that differentially expressed genes were involved in the regulation of signalling pathways of follicular development, cell cycle, material synthesis, energy metabolism, such as COL3A1, RPS8, ACTA2, RPL7 RPS6 and TNFAIP6 may play a key role in regulating the development of follicles. Our results show a comprehensive expression profile after superovulation and estrus synchronisation treatment. We provide the basis for further research on breeding techniques to improve the ovulation rate and birth rate of livestock.

Alterations of Cortisol and Melatonin Production by the Theca Interna Cells of Porcine Cystic Ovarian Follicles

Simple Summary

The mechanism of follicular cyst formation is largely unknown but changes in follicular composition are known to be involved. In particular, there is abnormal hormone secretion in cystic follicles. Here, we found there was disruption of hormone secretion in the fluid of cystic follicles in sows. The glucocorticoid receptor was highly expressed, and the melatonin receptor was weakly expressed in cystic follicles compared with control follicles. Thus, secretion of steroid hormones in cystic follicles is disrupted and disturbances in signaling via cortisol and melatonin are involved in the development of follicular cysts in sows.

Abstract

(1) Background: Cortisol and melatonin (MT) act in regulating follicular development. We hypothesized that abnormal levels of cortisol, MT, and steroids in theca interna cells might be involved in the development of follicular cysts in sows. (2) Methods: To test this hypothesis, we measured the mRNA levels of enzymes involved in steroid hormone synthesis, the glucocorticoid receptor (GR), and melatonin receptors (MTRs) in theca interna cells of cystic and normal porcine follicles. (3) Results: The concentrations of estradiol, progesterone, and cortisol were greater in cystic follicles than in control ones (p = 0.034, p = 0.020, p = 0.000), but the concentration of MT was significantly lower (p = 0.045). The levels of GR, 11β-HSD1, and 11β-HSD2 were higher in cystic follicles than in control l follicles. MT types 1 and 2 were significantly lower in cystic follicles (p < 0.05). The mRNA expression levels of genes encoding the steroid hormone synthesis enzymes, steroidogenic acute regulatory protein (StAR), recombinant cytochrome P45011A1 (CYP11A1), and 3β-hydroxysteroid dehydrogenase (3β-HSD) in theca interna cells of cystic follicles were significantly higher than in control follicles. Thus, there was disruption of hormone secretion in the fluid of cystic follicles in sows. (4) Conclusions: The levels of steroid hormones, cortisol and MT are disrupted in porcine cystic follicles.

Crocus sativus (saffron) petals extract and its active ingredient, anthocyanin improves ovarian dysfunction, regulation of inflammatory genes and antioxidant factors in testosterone-induced PCOS mice

ETHNOPHARMACOLOGICAL RELEVANCE

Saffron petal has traditionally been used to treat a variety of diseases, such as gynecological disease such as primary dysmenorrhea and premenstrual tension. Polycystic Ovary Syndrome (PCOS) is a form of gynecological disease that causes amenorrhea, infertility, menopausal and urogenital disorders. This disease may be treated with saffron petals.

AIM OF THE STUDY

In this study, the effects of saffron petal extract (SPE) and saffron petal anthocyanins (SPA) on ovarian hormones, steroidogenic enzymes, ovarian dysfunction, regulation of anti-inflammatory genes, and antioxidant factors in female PCOS mice were studied.

METHODS AND RESULTS

The PCOS mouse model was induced by testosterone enanthate (TE), and an in vivo evaluation of whether the dietary consumption of SPE and SPA improved the PCOS-like symptoms was conducted. The luteinizing hormone (LH), testosterone, and estrogen levels increased in PCOS mice, but decreased following SPE and SPA treatment. In the PCOS mice, the reduced follicular-stimulating hormone (FSH) progesterone levels were restored to that of normal controls with SPE and SPA treatment in serum. The transcription level(s) of gonadotropin receptors (Fshr and Lhr), steroid receptors (Pgr, and Esr1), inflammatory markers (TNFα, IL1ß, IL6 and IL18), inflammatory-related factors (NF-κB, NF-κB p65, IκB) and antioxidant enzymes (GPx, SOD, CAT, GST, and GSH) changed under the PCOS condition. Moreover, they were regulated by SPE and SPA treatment in PCOS mice ovaries. The reproductive tissues of TE induced PCOS mice were restored into estrogenic conditions from androgen environments. The study of antioxidant activity of SPE and SPA using FRAP and DPPH tests showed high antioxidant activity.

CONCLUSION

These results suggest that SPE and SPA ameliorates symptoms of PCOS by improving dysregulation of ovarian steroids, steroidogenic, antioxidant enzymes and inflammatory markers in PCOS mice.

Time-restricted feeding improves metabolic and endocrine profiles in mice with polycystic ovary syndrome

OBJECTIVES

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathy disorders in premenopausal women, which is characterized by hyperandrogenemia, anovulation, and polycystic ovarian morphology (PCOM). Time-restricted feeding (TRF) is a new intermittent restriction dietary pattern, which has been shown to have positive benefits on obesity and glycolipid metabolism disorders. We aimed to explore the effect of the feeding regimen (ad libitum vs. TRF) on the glycolipid metabolism and reproductive endocrine disorders in a PCOS mouse model.

METHODS

PCOS mouse model was induced by continuous subcutaneous administration of dihydrotestosterone for 21 days. Mice were fed a high-fat diet (HFD) for 8 weeks on an ad libitum or time- restricted diet (from 10:30 p.m. to 6:30 a.m.).

RESULTS

Compared to control mice, PCOS mice that received TRF treatment had significantly lower body weight, reduced adiposity, lower area under the curve (AUC) of glucose response in the oral glucose tolerance test (OGTT), and lower AUC in the insulin tolerance test (ITT). TRF also ameliorated lipid metabolism, as shown by a reduction in plasma lipid profiles (triglycerides and cholesterol) and the triglyceride content in the liver of PCOS mice. In terms of reproduction, the plasma androgen level, plasma estrogen (E2) level, and luteinizing hormone (LH)/follicle stimulating hormone (FSH) ratio in PCOS mice were significantly reduced after 8 weeks of TRF treatment. In addition, ovarian histology showed that TRF inhibits cyst formation and promotes corpus luteum formation.

CONCLUSION

In conclusion, TRF improved metabolic and endocrine profiles in mice with PCOS.

Cholecalciferol and metformin protect against lipopolysaccharide-induced endothelial dysfunction and senescence by modulating sirtuin-1 and protein arginine methyltransferase-1

Endothelial cell activation through nuclear factor-kappa-B (NFkB) and mitogen-activated protein kinases leads to increased biosynthesis of pro-inflammatory mediators, cellular injury and vascular inflammation under lipopolysaccharide (LPS) exposure. Recent studies report that LPS up-regulated global methyltransferase activity. In this study, we observed that a combination treatment with metformin (MET) and cholecalciferol (VD) blocked the LPS-induced S-adenosylmethionine (SAM)-dependent methyltransferase (SDM) activity in Eahy926 cells. We found that LPS challenge (i) increased arginine methylation through up-regulated protein arginine methyltransferase-1 (PRMT1) mRNA, intracellular concentrations of asymmetric dimethylarginine (ADMA) and homocysteine (HCY); (ii) up-regulated cell senescence through mitigated sirtuin-1 (SIRT1) mRNA, nicotinamide adenine dinucleotide (NAD+) concentration, telomerase activity and total antioxidant capacity; and (iii) lead to endothelial dysfunction through compromised nitric oxide (NOx) production. However, these LPS-mediated cellular events in Eahy926 cells were restored by the synergistic effect of MET and VD. Taken together, this study identified that the dual compound effect inhibits LPS-induced protein arginine methylation, endothelial senescence and dysfunction through the components of epigenetic machinery, SIRT1 and PRMT1, which is a previously unidentified function of the test compounds. In silico results identified the presence of vitamin D response element (VDRE) sequence on PRMT1 suggesting that VDR could regulate PRMT1 gene expression. Further characterization of the cellular events associated with the dual compound challenge, using gene silencing approach or adenoviral constructs for SIRT1 and/or PRMT1 under inflammatory stress, could identify therapeutic strategies to address the endothelial consequences in vascular inflammation-mediated atherosclerosis.

Integrated analyses of miRNA-mRNA expression profiles of ovaries reveal the crucial interaction networks that regulate the prolificacy of goats in the follicular phase

BACKGROUND

Litter size is an important index of mammalian prolificacy and is determined by the ovulation rate. The ovary is a crucial organ for mammalian reproduction and is associated with follicular development, maturation and ovulation. However, prolificacy is influenced by multiple factors, and its molecular regulation in the follicular phase remains unclear.

METHODS

Ten female goats with no significant differences in age and weight were randomly selected and divided into either the high-yielding group (n = 5, HF) or the low-yielding group (n = 5, LF). Ovarian tissues were collected from goats in the follicular phase and used to construct mRNA and miRNA sequencing libraries to analyze transcriptomic variation between high- and low-yield Yunshang black goats. Furthermore, integrated analysis of the differentially expressed (DE) miRNA-mRNA pairs was performed based on their correlation. The STRING database was used to construct a PPI network of the DEGs. RT-qPCR was used to validate the results of the predicted miRNA-mRNA pairs. Luciferase analysis and CCK-8 assay were used to detect the function of the miRNA-mRNA pairs and the proliferation of goat granulosa cells (GCs).

RESULTS

A total of 43,779 known transcripts, 23,067 novel transcripts, 424 known miRNAs and 656 novel miRNAs were identified by RNA-seq in the ovaries from both groups. Through correlation analysis of the miRNA and mRNA expression profiles, 263 negatively correlated miRNA-mRNA pairs were identified in the LF vs. HF comparison. Annotation analysis of the DE miRNA-mRNA pairs identified targets related to biological processes such as "estrogen receptor binding (GO:0030331)", "oogenesis (GO:0048477)", "ovulation cycle process (GO:0022602)" and "ovarian follicle development (GO:0001541)". Subsequently, five KEGG pathways (oocyte meiosis, progesterone-mediated oocyte maturation, GnRH signaling pathway, Notch signaling pathway and TGF-β signaling pathway) were identified in the interaction network related to follicular development, and a PPI network was also constructed. In the network, we found that CDK12, FAM91A1, PGS1, SERTM1, SPAG5, SYNE1, TMEM14A, WNT4, and CAMK2G were the key nodes, all of which were targets of the DE miRNAs. The PPI analysis showed that there was a clear interaction among the CAMK2G, SERTM1, TMEM14A, CDK12, SYNE1 and WNT4 genes. In addition, dual luciferase reporter and CCK-8 assays confirmed that miR-1271-3p suppressed the proliferation of GCs by inhibiting the expression of TXLNA.

CONCLUSIONS

These results increase the understanding of the molecular mechanisms underlying goat prolificacy. These results also provide a basis for studying interactions between genes and miRNAs, as well as the functions of the pathways in ovarian tissues involved in goat prolificacy in the follicular phase.

Vitamin D status determines the impact of metformin on circulating prolactin levels in premenopausal women

WHAT IS KNOWN AND OBJECTIVE

Metformin was found to normalize secretory function of overactive pituitary cells. Its effect on circulating thyrotropin levels was more pronounced in women receiving exogenous vitamin D. The aim of the current study was to investigate whether vitamin D status determines the impact of metformin on prolactin levels in premenopausal women with hyperprolactinaemia.

METHODS

The study population consisted of three groups of women with prediabetes and elevated prolactin levels: vitamin D-naïve women with vitamin D insufficiency (group 1; n = 19), women receiving vitamin D preparations because of vitamin D deficiency (group 2 n = 20), as well as vitamin D-naïve women with normal vitamin D status (group 3 n = 23). All participants were then treated with metformin (2.55-3 g daily). Circulating levels of glucose, insulin, prolactin, thyrotropin, free thyroid hormones, gonadotropins, estradiol, calcium and 25-hydroxyvitamin were determined at baseline and six months later.

RESULTS AND DISCUSSION

At baseline, prolactin levels were higher in group 1 than in the remaining groups of patients. Although metformin decreased glucose levels and improved insulin sensitivity in all treatment groups, this effect was more pronounced in groups 2 and 3. Only in subjects with 25-hydroxyvitamin D levels within the reference range, metformin reduced prolactin levels. The impact on prolactin levels correlated with 25-hydroxyvitamin D levels and with the improvement in insulin sensitivity. The drug produced a neutral effect on circulating levels of thyrotropin, free thyroid hormones, gonadotropins, estradiol, calcium and 25-hydroxyvitamin D.

WHAT IS NEW AND THE CONCLUSION

The results of the current study suggest that the impact of metformin on secretory function of overactive lactotropes depends on the vitamin D status of patients.

Vitamin D3 potentiates the nephroprotective effects of metformin in a rat model of metabolic syndrome: role of AMPK/SIRT1 activation and DPP-4 inhibition

The current study aimed to investigate the molecular mechanisms of metformin and vitamin D3-induced nephroprotection in a metabolic syndrome (MetS) rat model, evaluating the capacity of vitamin D3 to potentiate metformin action. MetS was induced by 10% fructose in drinking water and 3% salt in the diet. After 6 weeks, serum lipid profile and uric acid were measured, an oral glucose tolerance test (OGTT) was performed, and kidney function was investigated. In conjunction with the same concentrations of fructose and salt feeding, MetS rats with significant weight gain, dyslipidemia, hyperuricemia, and dysglycemia were treated orally with metformin (200 mg/kg), vitamin D3 (10 µg/kg), or both daily for 6 weeks. At the end of the study period, anthropometrical parameters were recorded, OGTT was reperformed, urine and blood samples were collected, and tissue samples were harvested at sacrifice. MetS rats showed dramatically declined renal function, enhanced intrarenal oxidative stress and inflammation, and extravagant renal histopathological damage with interstitial fibrosis. Metformin and vitamin D3 significantly reversed all the aforementioned deleterious effects in MetS rats. The study has verified the nephroprotective effects of metformin and vitamin D3 in MetS, accentuating the critical role of AMP-activated protein kinase/sirtuin-1 activation and dipeptidyl peptidase-4 inhibition. Given the synergistic effects of the combination, vitamin D3 is worth being investigated as an additional therapeutic agent for preventing MetS-induced nephropathy.

Oral Vitamin D supplementation impacts gene expression in granulosa cells in women undergoing IVF

STUDY QUESTION

Does oral Vitamin D supplementation alter the hormonal milieu of follicular fluid (FF) and the transcriptomic profile of luteinised granulosa cells (GCs) in women with Vitamin D deficiency undergoing IVF?

SUMMARY ANSWER

A transcriptomic signature relevant to oral Vitamin D supplementation in luteinised GCs was demonstrated, although Vitamin D supplementation did not alter hormone levels in FF.

WHAT IS KNOWN ALREADY

Vitamin D deficiency is linked to lower live birth rates among women undergoing IVF. It is unclear whether Vitamin D elicits a targeted action in reproductive physiology or is a surrogate marker of overall well-being. Several in-vitro studies, but none in vivo, have examined the impact of Vitamin D on the periovulatory follicle, focusing on GCs as a proxy marker of oocyte competence.

STUDY DESIGN, SIZE, DURATION

We present a report of secondary outcomes from the SUNDRO clinical trial, which was launched in 2016 to determine whether Vitamin D supplementation can improve the IVF outcomes of women who are deficient in Vitamin D (<30 ng/ml). FF samples of 145 women who were randomised to receive Vitamin D or placebo from March 2017 to January 2019 were collected. All follicles that were aspirated in our study measured ≥11 mm on the day of hCG trigger. The first cohort of samples was collected from the dominant follicle of each participant and utilised for hormone profiling (n = 50 Vitamin D, n = 45 Placebo). For the second cohort, the follicle aspirates of each participant were pooled to create a single FF sample, which was used for the isolation of GCs for gene expression studies (n = 20 Vitamin D, n = 30 placebo). Six of the samples from the second cohort were used for RNA-sequencing analysis (n = 3 Vitamin D, n = 3 placebo).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two academic infertility units were involved in the recruitment of the participants, who received a single dose of oral 25-hydroxyvitamin D (600 000 IU) or placebo, 2-12 weeks before oocyte retrieval. Women in both groups were deficient in Vitamin D, aged 18-39 years with a normal BMI (18-25 kg/m2) and <3 previous IVF cycles. The FF was aspirated at the time of oocyte retrieval and stored. Liquid chromatography tandem mass spectrometry was used to measure FF abundance of 25-hydroxyvitamin D, aldosterone, androstenedione, cortisol, cortisone, corticosterone, 11-deoxycorticosterone, 11-deoxycortisol, 21-deoxycortisol, dehydroepiandrosterone, dehydroepiandrosterone sulfate, dihydrotestosterone, oestradiol (E2), 17-OH-hydroxyprogesterone, progesterone (P4) and testosterone. GCs were isolated from pooled FFs and the transcriptome was evaluated by RNA-sequencing and RT-PCR. Ingenuity pathway analysis (IPA) was used to assess the top canonical pathways and upstream regulators mediating the action of Vitamin D.

MAIN RESULTS AND THE ROLE OF CHANCE

At oocyte retrieval, FF concentration of 25-hydroxyvitamin D was 2.8-fold higher (P < 0.001) in the Vitamin D group (39.5 ng/ml; n = 50) compared to placebo (13.8 ng/ml; n = 45) but no other hormonal differences were detected. In the placebo group, but not the Vitamin D group, weak correlations of 25-hydroxyvitamin D concentration with P4 (r = 0.31, P = 0.03) and E2 (r = 0.45, P = 0.002) were observed. RNA-sequencing identified 44 differentially expressed genes in the GCs of patients who received Vitamin D (n = 3) compared to placebo (n = 3). RT-PCR demonstrated upregulation of VDR (vitamin D receptor), GSTA3 (glutathione S-transferase A3) and IL21R (interleukin 21 receptor), and downregulation of P T GS2 (prostaglandin-endoperoxide synthase 2), KLF4 (kruppel-like factor 4), T RP C4 (transient receptor potential cation channel subfamily C member 4), VEGF (vascular endothelial growth factor), RXRB (retinoid X receptor beta) and AGER (advanced glycosylation end-product specific receptor) genes in the Vitamin D (n = 17) versus placebo (n = 27) group. IPA suggested roles of Vitamin D in antioxidant defence.

LIMITATIONS, REASONS FOR CAUTION

Interpretation of the data is influenced by our intervention strategy (2-12 weeks prior to retrieval). As folliculogenesis may last 5-6 months, our protocol can only examine with confidence the impact of Vitamin D on the final stages of follicular growth. Furthermore, we examined the hormonal profile of the dominant follicle only, while the GC data reflect the transcriptome of all (pooled) follicles large enough to be used for IVF. Luteinised GCs from controlled ovarian stimulation were used in this study, which may be functionally distinct from the GCs of developing follicles. Moreover, the sample size for RNA-sequencing analysis was low (n = 3 per group), regardless of validation by RT-PCR that was performed on a larger cohort, introducing complexity to the IPA analysis, which required an input of data with P-adjusted <0.08 instead of <0.05 to be informative.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first in-vivo study to show that Vitamin D supplementation alters gene expression in luteinised GCs. In contrast to some in-vitro evidence, no effect of the intervention on expression of genes encoding steroidogenic enzymes was observed. Unlike other studies, our results suggest that supplementation with Vitamin D is unlikely to directly influence hormone availability in FF. Our findings instead reinforce the hypothesis that Vitamin D could be considered one of the gatekeepers in protecting against an exaggerated response to ovarian stimulation.

STUDY FUNDING/COMPETING INTEREST(S)

The study has been funded by the Italian Ministry of Health (RF-2013-02358757) following peer review in the competitive 'Bando di Ricerca Finalizzata e Giovani Ricercatori 2013' for the clinical trial SUNDRO (EudraCT registration number 2015-004233-27). There are no competing interests.

TRIAL REGISTRATION NUMBER

EudraCT registration number 2015-004233-27.

1,25-(OH)2D3 ameliorates renal interstitial fibrosis in UUO rats through the AMPKα/mTOR pathway

Objective

To investigate the effects of 1,25(OH)₂D₃ on renal fibrosis associated with the AMP-activated protein kinase (AMPK)α/mechanistic target of rapamycin (mTOR) signalling pathway in a rat model of unilateral ureteral obstruction (UUO).

Methods

A total of 54 male Sprague Dawley rats were randomly divided into three groups: sham-operation group, UUO group, and UUO plus calcitriol (3 ng/100 g) group. Renal tissue was excised for histological examination by immunohistochemistry and Western blot, and for gene expression analysis using real-time polymerase chain reaction.

Results

1,25(OH)₂D₃ enhanced AMPKα levels, inhibited mTOR levels and slowed the development of interstitial fibrosis in kidney tissue. Compared with the UUO plus calcitriol group, UUO rats demonstrated more severe renal damage characterized by marked tubular atrophy, interstitial fibrosis and significant induction of fibrogenic transforming growth factor-β1 and increased extra-cellular matrix proteins (α-smooth muscle actin and collagen type III), and decreased E-cadherin.

Conclusion

Treatment with 1,25(OH)₂D₃ altered the AMPKα/mTOR signalling pathway to suppress excessive fibroblast activation observed in UUO rats. This may serve as a novel mechanism to ameliorate renal dysfunction and fibrotic lesions.

The Effect of RBP4 on microRNA Expression Profiles in Porcine Granulosa Cells

Simple Summary

Retinol binding protein 4 (RBP4), mainly secreted by the liver and adipocytes, is a transporter of vitamin A. RBP4 has been shown to be involved in several pathophysiological processes, such as polycystic ovary syndrome (PCOS), obesity, insulin resistance, and cardiovascular risk. However, the role of RBP4 in mammalian follicular granulosa cells (GCs) remains largely unknown. To characterize the molecular pathways associated with the effects of RBP4 on GCs, we used sRNA deep sequencing to detect differential microRNA (miRNA) expression in GCs overexpressing RBP4. A total of 17 miRNAs were significantly different between the experimental and control groups. Our results support the notion that several miRNAs are involved in important biological processes associated with folliculogenesis and pathogenesis. These results will be useful for further studies investigating the role of RBP4 in porcine GCs.

Abstract

Retinol binding protein 4 (RBP4) is a transporter of vitamin A that is secreted mainly by hepatocytes and adipocytes. It affects diverse pathophysiological processes, such as obesity, insulin resistance, and cardiovascular diseases. MicroRNAs (miRNAs) have been reported to play indispensable roles in regulating various developmental processes via the post-transcriptional repression of target genes in mammals. However, the functional link between RBP4 and changes in miRNA expression in porcine granulosa cells (GCs) remains to be investigated. To examine how increased expression of RBP4 affects miRNA expression, porcine GCs were infected with RBP4-targeted lentivirus for 72 h, and whole-genome miRNA profiling (miRNA sequencing) was performed. The sequencing data were validated using real-time quantitative polymerase chain reaction (RT-qPCR) analysis. As a result, we obtained 2783 known and 776 novel miRNAs. In the experimental group, 10 and seven miRNAs were significantly downregulated and upregulated, respectively, compared with the control group. Ontology analysis of the biological processes of these miRNAs indicated their involvement in a variety of biological functions. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that these miRNAs were involved mainly in the chemokine signaling pathway, peroxisome proliferators-activated receptors (PPAR) signaling pathway, insulin resistance pathway, nuclear factor-kappa B(NF-kappa B) signaling pathway, and steroid hormone biosynthesis. Our results indicate that RBP4 can regulate the expression of miRNAs in porcine GCs, with consequent physiological effects. In summary, this study profiling miRNA expression in RBP4-overexpressing porcine GCs provides an important reference point for future studies on the regulatory roles of miRNAs in the porcine reproductive system.

Mitochondrial Dysfunction and Chronic Inflammation in Polycystic Ovary Syndrome

Polycystic ovarian syndrome (PCOS) is the most common endocrine-metabolic disorder affecting a vast population worldwide; it is linked with anovulation, mitochondrial dysfunctions and hormonal disbalance. Mutations in mtDNA have been identified in PCOS patients and likely play an important role in PCOS aetiology and pathogenesis; however, their causative role in PCOS development requires further investigation. As a low-grade chronic inflammation disease, PCOS patients have permanently elevated levels of inflammatory markers (TNF-α, CRP, IL-6, IL-8, IL-18). In this review, we summarise recent data regarding the role of mtDNA mutations and mitochondrial malfunctions in PCOS pathogenesis. Furthermore, we discuss recent papers dedicated to the identification of novel biomarkers for early PCOS diagnosis. Finally, traditional and new mitochondria-targeted treatments are discussed. This review intends to emphasise the key role of oxidative stress and chronic inflammation in PCOS pathogenesis; however, the exact molecular mechanism is mostly unknown and requires further investigation.

Energy sensors and reproductive hypothalamo-pituitary ovarian axis (HPO) in female mammals: Role of mTOR (mammalian target of rapamycin), AMPK (AMP-activated protein kinase) and SIRT1 (Sirtuin 1)

In female, energy metabolism influences reproductive function by modulating the Hypothalamic Pituitary Ovarian axis including the hypothalamic GnRH neuronal network, the pituitary gonadotropin secretion and the ovarian follicle growth and steroidogenesis. Several hormones and neuropeptides or metabolites are important signals between energy balance and reproduction. These energy sensors mediate their action on reproductive cells through specific kinases or signaling pathways. This review focuses on the role of three main enzymes-specifically, mTOR, AMPK, and SIRT1 at the hypothalamic pituitary and ovarian axis in normal female fertility and then we discuss their possible involvement in some women reproductive disorders known to be associated with metabolic complications, such as polycystic ovary syndrome (PCOS) and premature ovarian failure (POF).

Novel mechanisms underlying anti-polycystic ovary like syndrome effects of electroacupuncture in rats: suppressing SREBP1 to mitigate insulin resistance, mitochondrial dysfunction and oxidative stress

Background

Acupuncture, a therapy of traditional Chinese medicine, is confirmed to exert the therapeutic action on polycystic ovary syndrome (PCOS). However, the detailed therapeutic mechanisms of acupuncture in PCOS remain ambiguous. In this study, we further investigated whether electroacupuncture (EA) alleviated PCOS-like symptoms in rats via regulating a metabolic regulator, sterol regulatory element binding protein-1 (SREBP1).

Methods

The PCOS-like rat model was built by hypodermic injection with dehydroepiandrosterone (DHEA). The rats were subjected to EA intervention (ST29 and SP6 acupuncture points) for 5 weeks. Primary granulosa cells were isolated from control and PCOS-like rats for evaluating insulin resistance, mitochondrial dysfunction and oxidative stress in vitro.

Results

The expression of SREBP1 was increased in PCOS-like rats, which was suppressed by EA treatment. In addition, lentivirus-mediated overexpression of SREBP1 restrained EA treatment-induced improvement in pathological changes, serum hormone levels and insulin resistance in rats. In addition, overexpression of SREBP1 repressed insulin-stimulated phosphorylation of insulin receptor β (IR) and AKT in primary granulosa cells. Moreover, upregulation of SREBP1 further exacerbated mitochondrial dysfunction and oxidative stress in granulosa cells isolated from PCOS-like rats. Mechanically, EA treatment suppressed SREBP1 expression through inducing the activation of AMP-activated protein kinase (AMPK) signaling pathway in PCOS-like rats.

Conclusion

EA intervention alleviated PCOS-like symptoms in rats via improving IR, mitochondrial dysfunction and oxidative stress through regulating SREBP1, a lipid metabolism regulator. Our findings illuminate the novel protective mechanisms of EA in the treatment of PCOS.

Altered vitamin D3 metabolism in the ovary and periovarian adipose tissue of rats with letrozole-induced PCOS

Vitamin D₃ (VD₃) plays an important role in the ovary and its deficiency is associated with ovarian pathologies, including polycystic ovary syndrome (PCOS). However, there is no data related to VD₃ metabolism in the ovary during PCOS. Herein, we investigated differences in the expression of VD₃ receptor (VDR) and key VD₃ metabolic enzymes, 1α-hydroxylase (CYP27B1) and 24-hydroxylase (CYP24A1), in the ovary and periovarian adipose tissue (POAT) of control (proestrus and diestrus) and PCOS induced by letrozole rats. Vdr, Cyp27b1 and Cyp24a1 mRNA expression was determined, their protein abundance was examined and immunolocalized. Furthermore, VD₃ metabolite concentrations in plasma (25OHD) and tissues (ovary and POAT; 1,25(OH)₂D₃), and plasma calcium level were determined. 25OHD concentration decreased markedly in letrozole-treated rats in comparison with controls, whereas calcium concentration did not vary among the examined groups. The amount of 1,25(OH)₂D₃ decreased in both ovary and POAT of PCOS rats. In the ovary, we found decreased Cyp27b1 and increased Vdr mRNA expression in letrozole-treated and diestrus control group. Corresponding protein abundances were down-regulated and up-regulated, respectively but only following letrozole treatment. In POAT, only Cyp27b1 transcript level and CYP27B1 protein abundance were decreased in letrozole-treated rats. VDR was immunolocalized in healthy and cystic follicles, while CYP27B1 and CYP24A1 were found exclusively in healthy ones. Concluding, our results provide the first evidence of disrupted VD₃ metabolism in the ovary and POAT of PCOS rats. The reduced 1,25(OH)₂D₃ concentration in those tissues suggests their contribution to VD₃ deficiency observed in PCOS and might implicate in PCOS pathogenesis.

Pomegranate derivative urolithin A enhances vitamin D receptor signaling to amplify serotonin-related gene induction by 1,25-dihydroxyvitamin D

Mediated by the nuclear vitamin D receptor (VDR), the hormonally active vitamin D metabolite, 1,25-dihydroxyvitamin D₃ (1,25D), is known to regulate expression of genes impacting calcium and phosphorus metabolism, the immune system, and behavior. Urolithin A, a nutrient metabolite derived from pomegranate, possibly acting through AMP kinase (AMPK) signaling, supports respiratory muscle health in rodents and longevity in C. elegans by inducing oxidative damage-reversing genes and mitophagy. We show herein that urolithin A enhances transcriptional actions of 1,25D driven by co-transfected vitamin D responsive elements (VDREs), and dissection of this genomic effect in cell culture reveals: 1) urolithin A concentration-dependency, 2) occurrence with isolated natural VDREs, 3) nuclear receptor selectivity for VDR over ER, LXR and RXR, and 4) significant 3- to 13-fold urolithin A-augmentation of 1,25D-dependent mRNA encoding the widely expressed 1,25D-detoxification enzyme, CYP24A1, a benchmark vitamin D target gene. Relevant to potential behavioral effects of vitamin D, urolithin A elicits enhancement of 1,25D-dependent mRNA encoding tryptophan hydroxylase-2 (TPH2), the serotonergic neuron-expressed initial enzyme in tryptophan metabolism to serotonin. Employing quantitative real time-PCR, we demonstrate that TPH2 mRNA is induced 1.9-fold by 10 nM 1,25D treatment in culture of differentiated rat serotonergic raphe (RN46A-B14) cells, an effect magnified 2.5-fold via supplementation with 10 μM urolithin A. This potentiation of 1,25D-induced TPH2 mRNA by urolithin A is followed by a 3.1- to 3.7-fold increase in serotonin concentration in culture medium from the pertinent neuronal cell line, RN46A-B14. These results are consistent with the concept that two natural nutrient metabolites, urolithin A from pomegranate and 1,25D from sunlight/vitamin D, likely acting via AMPK and VDR, respectively, cooperate mechanistically to effect VDRE-mediated regulation of gene expression in neuroendocrine cells. Finally, gedunin, a neuroprotective natural product from Indian neem tree that impacts the brain derived neurotropic factor pathway, similarly potentiates 1,25D/VDR-action.

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Hormonal 1,25-dihydroxyvitamin D acts in brain to induce tryptophan hydroxylase-2.

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Urolithin A derived from ellagitannins in pomegranates curbs neuroinflammation.

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Urolithin A enhances the transcriptional actions of 1,25-dihydroxyvitamin D.

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Urolithin A raises 1,25-dihydroxyvitamin D-induced tryptophan hydroxylase-2 mRNA.

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Serotonin rises in raphe cells exposed to urolithin A and 1,25-dihydroxyvitamin D.

Updates on molecular and environmental determinants of luteal progesterone production

Progesterone, a critical hormone in reproduction, is a key sex steroid in the establishment and maintenance of early pregnancy and serves as an intermediary for synthesis of other steroid hormones. Progesterone production from the corpus luteum is a tightly regulated process which is stimulated and maintained by multiple factors, both systemic and local. Multiple regulatory systems, including classic mediators of gonadotropin stimulation such as the cAMP/PKA pathway and TGFβ-mediated signaling pathways, as well as local production of hormonal factors, exist to promote granulosa cell function and physiological fine-tuning of progesterone levels. In this manuscript, we provide an updated narrative review of the known mediators of human luteal progesterone and highlight new observations regarding this important process, focusing on studies published within the last five years. We will also review recent evidence suggesting that this complex system of progesterone production is sensitive to disruption by exogenous environmental chemicals that can mimic or interfere with the activities of endogenous hormones.

TGF-β1 promotes vitamin D-induced prostaglandin E2 synthesis by upregulating vitamin D receptor expression in human granulosa-lutein cells

There is increasing evidence showing the importance of vitamin D (Vit D) and its nuclear receptor, the Vit D receptor (VDR), in female reproductive health. Transforming growth factor-β1 (TGF-β1) and its functional receptors are expressed in human oocytes and granulosa cells that participate in follicular development and ovulation. Recently, Sma- and Mad-related protein 3 (SMAD3; a downstream effector of TGF-β1) has been proposed to mediate crosstalk between the Vit D and TGF-β1 signaling pathways, but this relationship has not been fully explored and has yet to be tested in human granulosa-lutein (hGL) cells. In this study, we showed that TGF-β1 significantly promoted the expression of VDR, and this stimulatory effect occurred through the activin receptor-like kinase 5 type I receptor-mediated SMAD3 and ERK1/2 signaling pathways in hGL cells. Additionally, we showed that Vit D increased the expression of cyclooxygenase 2 (COX-2) and the synthesis of prostaglandin E2 (PGE2) in a time- and dose-dependent manner. Furthermore, we demonstrated a synergistic effect of TGF-β1 and Vit D on the expression of COX-2 and synthesis of PGE2, and this effect could be attenuated by silencing the expression of VDR. Our findings indicate that TGF-β1 upregulates the expression of VDR, which promotes Vit D-induced COX-2 expression and subsequent PGE2 production by activating the SMAD3 and ERK1/2 signaling pathways in hGL cells.

Daily and seasonal mitochondrial protection: Unraveling common possible mechanisms involving vitamin D and melatonin

From an evolutionary point of view, vitamin D and melatonin appeared very early and share functions related to defense mechanisms. In the current clinical setting, vitamin D is exclusively associated with phosphocalcic metabolism. Meanwhile, melatonin has chronobiological effects and influences the sleep-wake cycle. Scientific evidence, however, has identified new actions of both molecules in different physiological and pathological settings. The biosynthetic pathways of vitamin D and melatonin are inversely related relative to sun exposure. A deficiency of these molecules has been associated with the pathogenesis of cardiovascular diseases, including arterial hypertension, neurodegenerative diseases, sleep disorders, kidney diseases, cancer, psychiatric disorders, bone diseases, metabolic syndrome, and diabetes, among others. During aging, the intake and cutaneous synthesis of vitamin D, as well as the endogenous synthesis of melatonin are remarkably depleted, therefore, producing a state characterized by an increase of oxidative stress, inflammation, and mitochondrial dysfunction. Both molecules are involved in the homeostatic functioning of the mitochondria. Given the presence of specific receptors in the organelle, the antagonism of the renin-angiotensin-aldosterone system (RAAS), the decrease of reactive species of oxygen (ROS), in conjunction with modifications in autophagy and apoptosis, anti-inflammatory properties inter alia, mitochondria emerge as the final common target for melatonin and vitamin D. The primary purpose of this review is to elucidate the common molecular mechanisms by which vitamin D and melatonin might share a synergistic effect in the protection of proper mitochondrial functioning.

Comprehensive analysis of mRNAs and miRNAs in the ovarian follicles of uniparous and multiple goats at estrus phase

Background

Fertility is an important economic trait in the production of meat goat, and follicular development plays an important role in fertility. Although many mRNAs and microRNAs (miRNAs) have been found to play critical roles in ovarian biological processes, the interaction between mRNAs and miRNAs in follicular development is not yet completely understood. In addition, less attention has been given to the study of single follicle (dominant or atretic follicle) in goats. This study aimed to identify mRNAs, miRNAs, and signaling pathways as well as their interaction networks in the ovarian follicles (large follicles and small follicles) of uniparous and multiple Chuanzhong black goats at estrus phase using RNA-sequencing (RNA-seq) technique.

Results

The results showed that there was a significant difference in the number of large follicles between uniparous and multiple goats (P < 0.05), but no difference in the number of small follicles was observed (P > 0.05). For the small follicles of uniparous and multiple goats at estrus phase, 289 differentially expressed mRNAs (DEmRNAs) and 16 DEmiRNAs were identified; and for the large follicles, 195 DEmRNAs and 7 DEmiRNAs were identified. The functional enrichment analysis showed that DE genes in small follicles were significantly enriched in ovarian steroidogenesis and steroid hormone biosynthesis, while in large follicles were significantly enriched in ABC transporters and steroid hormone biosynthesis. The results of quantitative real-time polymerase chain reaction were consistent with those of RNA-seq. Analysis of the mRNA-miRNA interaction network suggested that CD36 (miR-122, miR-200a, miR-141), TNFAIP6 (miR-141, miR-200a, miR-182), CYP11A1 (miR-122), SERPINA5 (miR-1, miR-206, miR-133a-3p, miR-133b), and PTGFR (miR-182, miR-122) might be related to fertility, but requires further research on follicular somatic cells.

Conclusions

This study was used for the first time to reveal the DEmRNAs and DEmiRNAs as well as their interaction in the follicles of uniparous and multiple goats at estrus phase using RNA-seq technology. Our findings provide new clues to uncover the molecular mechanisms and signaling networks of goat reproduction that could be potentially used to increase ovulation rate and kidding rate in goat.

Vitamin D3 affects mitochondrial biogenesis through mitogen-activated protein kinase in polycystic ovary syndrome mouse model

Polycystic ovarian syndrome (PCOS) is a disorder characterized by oligomenorrhea, anovulation, and hyperandrogenism. Altered mitochondrial biogenesis can result in hyperandrogenism. The goal of this study was to examine the effect of vitamin D3 on mitochondrial biogenesis of the granulosa cells in the PCOS-induced mouse model. Vitamin D3 applies its effect via the mitogen-activated pathway kinase-extracellular signal-regulated kinases (MAPK-ERK1/2) pathway. The PCOS mouse model was induced by the injection of dehydroepiandrosterone (DHEA). Isolated granulosa cells were subsequently treated with vitamin D3, MAPK activator, and MAPK inhibitor. Gene expression levels were measured using real-time polymerase chain reaction. MAPK proteins were investigated by western blot analysis. We also determined reactive oxygen species (ROS) levels with 2', 7'-dichlorofluorescein diacetate. Mitochondrial membrane potential (mtMP) was also measured by TMJC1. Mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator 1-α and nuclear respiratory factor), antioxidant (superoxide dismutase, glutathione peroxidase, and catalase), and antiapoptotic (B-cell lymphoma-2) genes were upregulated in the PCOS mice that treated with vitamin D3 compared with the PCOS mice without any treatment. Vitamin D3 and MAPK activator-treated groups also reduced ROS levels compared with the nontreated PCOS group. In summary, vitamin D3 and MAPK activator increased the levels of mitochondrial biogenesis, MAPK pathway, and mtMP markers, while concomitantly decreased ROS levels in granulosa cells of the PCOS-induced mice. This study suggests that vitamin D3 may improve mitochondrial biogenesis through stimulation of the MAPK pathway in cultured granulosa cells of DHEA-induced PCOS mice which yet to be investigated.

Effects of vitamin D in the nervous system: Special focus on interaction with steroid hormone signalling and a possible role in the treatment of brain cancer

The active vitamin D hormone, 1,25-dihydroxyvitamin D₃ , exerts many physiological actions in the body, including effects on the nervous system. Studies of steroidogenesis in cells of the nervous system and elsewhere not only indicate that 1,25-dihydroxyvitamin D₃ affects steroidogenic pathways but also suggest varying responses in different cell types. For example, 1,25-dihydroxyvitamin D₃ stimulates the expression of aromatase in human glioma but not in human neuroblastoma cells or rat astrocytes. However, in astrocytes, 1,25-dihydroxyvitamin D₃ suppresses 3β-hydroxysteroid dehydrogenase and steroid 17-hydroxylase/lyase. Other studies indicate cross-talk between vitamin D signalling and signalling of oestrogens, progesterone or glucocorticoids. Reported data indicate synergistic effects of combinations of 1,25-dihydroxyvitamin D₃ and other steroid hormones on neuroinflammation, neurite outgrowth and neuroprotection. Also, dysregulation of steroid pathways affecting brain cells is found in vitamin D deficiency. Thus, several studies suggest that active vitamin D may affect steroid hormone synthesis and/or signalling in the nervous system, although the potential mechanisms for these responses remain unclear. 1,25-Dihydroxyvitamin D₃ suppresses proliferation in several cell types and is therefore of interest in cancer treatment. Also, epidemiological studies associate vitamin D levels with cancer risk or outcomes. Reported data on tumours of the nervous system are mainly on glioma, a common type of brain cancer. Expression of the vitamin D receptor in glioma tumours is associated with improved survival. Several studies show that 1,25-dihydroxyvitamin D₃ and vitamin D analogues (synthetic vitamin D-like compounds) suppress proliferation and migration in human vitamin D receptor-expressing glioma cell lines. Studies on mechanisms for actions of 1,25-dihydroxyvitamin D₃ or its analogues indicate regulation of cell cycle proteins and senescence markers. These compounds also show synergism in combination with other cancer therapies treating glioma. From the data available, vitamin D analogues emerge as interesting candidates for the future improved treatment of human glioma and possibly also other cancers of the nervous system.

Polycystic ovarian syndrome: Correlation between hyperandrogenism, insulin resistance and obesity

Polycystic ovary syndrome (PCOS) is a complex and heterogeneous endocrine disease characterized by clinical or laboratorial hyperandrogenism, oligo-anovulation and metabolic abnormalities, including insulin resistance, excessive weight or obesity, type II diabetes, dyslipidemia and an increased risk of cardiovascular disease. The most significant clinical manifestation of PCOS is hyperandrogenism. Excess androgen profoundly affects granulosa cell function and follicular development via complex mechanisms that lead to obesity and insulin resistance. Most PCOS patients with hyperandrogenism have steroid secretion defects that result in abnormal folliculogenesis and failed dominant follicle selection. Hyperandrogenism induces obesity, hairy, acne, and androgenetic alopecia. These symptoms can bring great psychological stress to women. Drugs such as combined oral contraceptive pills, metformin, pioglitazone and low-dose spironolactone help improve pregnancy rates by decreasing androgen levels in vivo. Notably, PCOS is heterogeneous, and hyperandrogenism is not the only pathogenic factor. Obesity and insulin resistance aggravate the symptoms of hyperandrogenism, forming a vicious cycle that promotes PCOS development. Although numerous studies have been conducted, the definitive pathogenic mechanisms of PCOS remain uncertain. This review summarizes and discusses previous and recent findings regarding the relationship between hyperandrogenism, insulin resistance, obesity and PCOS.

Baicalin ameliorates polycystic ovary syndrome through AMP-activated protein kinase

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder and regarded as the leading cause of anovulatory infertility. PCOS is characterized by reproductive dysfunction and metabolic disorders. Baicalin (BAL) is one of the most potent bioactive flavonoids isolated from the radix of Scutellaria baicalensis. In the present study, we investigated the potential effects of BAL on PCOS in dehydroepiandrosterone-treated rats. We found that BAL notably reduced the serum levels of free testosterone, total testosterone, follicle-stimulating hormone, luteinizing hormone, progesterone, and estradiol in PCOS rats. The increase of serum insulin level and HOMA-IR was markedly inhibited by BAL. Moreover, BAL decreased body weights, increased the number of rats with the regular estrous cycle, and ameliorated ovarian histological changes and follicular development in the DHEA-treated PCOS rats. The increase of pro-inflammatory cytokines (TNFα, IL-1β, and IL-18) and decrease of anti-inflammatory cytokine (IL-10) in PCOS rats were suppressed by BAL. BAL induced a significant decrease in the mRNA expression of steroidogenic enzymes, including 3β-HSD, CYP11A1, CYP19A1, StAR, in ovarian tissues in PCOS rats. Furthermore, BAL inhibited the decrease of AMPK protein level and phosphorylation, the decrease of Akt phosphorylation and the increase of 5α-reductase enzyme 1 expression in ovarian tissues in PCOS rats. The effects of BAL were inhibited by an inhibitor of AMPK, dorsomorphin. The upregulation of AMPK contributed to the beneficial effects of BAL. The results highlight the potential role of BAL for the intervention of PCOS.

Diabetic Hemodialysis: Vitamin D Supplementation and its Related Signaling Pathways Involved in Insulin and Lipid Metabolism

BACKGROUND

This study was conducted to determine the effects of vitamin D supplementation on some of the gene expressions related to insulin and lipid metabolism in diabetic hemodialysis (HD) patients.

METHODS

A double-blind, randomized, placebo-controlled clinical trial was carried out in 55 patients with diabetic HD. The current project used two groups in which each subject received vitamin D supplements (50,000 IU, n=28) or placebo (50,000 IU, n=27) every 2 weeks for 12 weeks. Gene expression analyses (RT-PCR) were included to obtain the rate of gene expression of the related insulin and lipid metabolism genes in peripheral blood mononuclear cells (PBMCs) of patients with diabetic HD.

RESULTS

Our data revealed that consumption of vitamin D supplementation enables to overexpress the peroxisome proliferation-activated receptor gamma (PPAR-γ) (P=0.001), AKT (P=0.04), PI3K (P=0.02), insulin receptor substrate-1 (IRS1) (P0.008) and glucose transporter type 4 (GLUT-4) (P=0.01) and downregulate the expression of protein kinase C (PKC) (P=0.001) in patients with diabetic HD than control group following the 12-week intervention. In addition, vitamin D supplementation downregulated low-density lipoprotein receptor (LDLR) (P=0.03) expression in the subjects with diabetic HD than the control group. Vitamin D supplementation did not show any effects on the expression of pyruvate dehydrogenase kinase 1 (PDK1) (P=0.37), IRS2 (P=0.90) and lipoprotein (a) [Lp(a)] (P=0.05).

CONCLUSION

Our findings confirmed that diabetic HD subjects who received the vitamin D supplementation (for 12 weeks), showed a significant overexpression in the PPAR-γ, AKT, PI3K, IRS1 and GLUT4 genes, and also showed a significant downregulation in the PKC and LDLR genes. Moreover, no effects on PDK1, IRS2 and Lp(a) expression were observed.

Metabolic Control of Dendritic Cell Functions: Digesting Information

Dendritic cells (DCs) control innate and adaptive immunity by patrolling tissues to gather antigens and danger signals derived from microbes and tissue. Subsequently, DCs integrate those environmental cues, orchestrate immunity or tolerance, and regulate tissue homeostasis. Recent advances in the field of immunometabolism highlight the notion that immune cells markedly alter cellular metabolic pathways during differentiation or upon activation, which has important implications on their functionality. Previous studies showed that active oxidative phosphorylation in mitochondria is associated with immature or tolerogenic DCs, while increased glycolysis upon pathogen sensing can promote immunogenic DC functions. However, new results in the last years suggest that regulation of DC metabolism in steady state, after immunogenic activation and during tolerance in different pathophysiological settings, may be more complex. Moreover, ontogenically distinct DC subsets show different functional specializations to control T cell responses. It is, thus, relevant how metabolism influences DC differentiation and plasticity, and what potential metabolic differences exist among DC subsets. Better understanding of the emerging connection between metabolic adaptions and functional DC specification will likely allow the development of therapeutic strategies to manipulate immune responses.

The role of vitamin D in ovarian cancer: epidemiology, molecular mechanism and prevention

Vitamin D is a fat-soluble prohormone best known for its role in maintaining calcium homeostasis. Large numbers of epidemiological studies have shown that vitamin D plays an important role in cancer prevention by regulating cellular proliferation and metabolism. Studies of the cellular mechanism of vitamin D in ovarian cancer strongly suggest that it exhibits protective and antitumorigenic activities through genomic and nongenomic signal transduction pathways. These results indicate that vitamin D deficiency results in an increase in the risk of developing ovarian cancer and that vitamin supplements may potentially be an efficient way of preventing cancer. Consequently, this review describes the epidemiology, molecular mechanism and evidence linking vitamin D deficiency to ovarian cancer.