Whole-Exome Sequencing Analysis of Idiopathic Hypogonadotropic Hypogonadism: Comparison of Varicocele and Nonobstructive Azoospermia.

As a rare disease leading to male infertility, idiopathic hypogonadotropic hypogonadism (IHH) has strong heterogeneity of clinical phenotype and gene mutation. At present, there is no effective diagnosis and treatment method for this disease. This study is to explore the possible new pathogenic gene of idiopathic hypogonadotrophic hypogonadism and the pathological mechanism affecting its occurrence. We performed a whole-exome sequencing on 9 patients with normosmic idiopathic hypogonadotropic hypogonadism (nIHH), 19 varicocele patients with asthenospermia, oligospermia, or azoospermia, 5 patients with simple nonobstructive azoospermia, and 13 normal healthy adult males and carried out comparative analysis, channel analysis, etc. After preliminary sequencing screening, 309-431 genes harbouring variants, including SNPs and indels, were predicted to be harmful per single patient in each group. In genetic variations of nIHH patients' analysis, variants were detected in 10 loci and nine genes in nine patients. And in co-analysis of the three patient groups, nine nIHH patients, 19 VC patients, and five SN patients shared 116 variants, with 28 variant-harbouring genes detected in five or more patients. We found that the NEFH, CCDC177, and PCLO genes and the Gene Ontology pathways GO:0051301: cell division and GO:0090066: regulation of anatomical structure size may be key factors in the pathogenic mechanism of IHH. Our results suggest that the pathogenic mechanism of IHH is not limited to the central nervous system effects of GnRH but may involve other heterogeneous pathogenic genetic variants that affect peripheral organs.

Effect of SGLT2 Inhibitors on Improving Glucolipid Metabolism and Reproductive Hormone Status in Overweight/Obese Women with PCOS: A Systematic Review and Meta-Analysis.

BACKGROUND: Obesity, insulin resistance, and hyperandrogenemia are commonly seen in women with polycystic ovary syndrome (PCOS), and these three conditions form a vicious cycle leading to reproductive and metabolic abnormalities. Metformin improves the symptoms of PCOS by increasing insulin sensitivity but is not therapeutically optimal. Recent studies have reported that sodium-glucose co-transporter protein receptor inhibitors improve insulin resistance and reduce the weight of patients with PCOS. We performed a meta-analysis to assess the influence of sodium-glucose co-transporter protein-2 (SGLT2) inhibitors on anthropometric, glycolipid metabolism and reproductive outcomes after therapy of overweight/obese women with PCOS. METHODS: We searched the relevant literature published up to April 2023. Information on the effect of SGLT2 inhibitors on overweight/obese patients with PCOS was extracted independently by two reviewers. Review Manager 5.3 was used for meta-analysis. RESULTS: Five randomized controlled trials that met our criteria were retrieved. Our meta-analysis demonstrated that in overweight/obese patients with PCOS, SGLT2 inhibitors treatment was significantly superior to metformin treatment in terms of reducing body weight (P = 0.02, I2 = 36%), decreasing dehydroepiandrosterone sulfate concentrations [SMD = -0.42, 95% CI (-0.76, -0.07), I2 = 22%, P = 0.02], and reducing the incidence of nausea [RR = 0.35, 95% CI (0.21, 0.60), I2 = 71%, P = 0.0001]. CONCLUSIONS: SGLT2 inhibitors are a possible alternative therapy for treating overweight/obese women with PCOS who do not respond favorably to metformin treatment. However, further large randomized controlled trials and cost-effectiveness analyses are warranted to guide the implementation of SGLT2 inhibitors treatment in this population.

Expression of aldose reductase in mouse endometrial epithelial cells and its role in sperm capacitation.

The survival, motility and capacitation of sperm in the female reproductive tract are important prerequisites for fertilization. The uterus is the main location for sperm capacitation. One of the most important physiological functions of the endometrial epithelium is to create a suitable uterine environment under the regulation of ovarian hormones, to ensure sperm capacitation. The composition of uterine fluid directly affects sperm capacitation. Fructose is an important component of semen that supports sperm viability and motility. Aldose reductase, a rate-limiting enzyme in the polyol pathway, metabolizes sorbitol and fructose, thereby supplying cells with necessary energy for functional activities. Existing studies have reported the presence aldose reductase in the endometrium, leading us to hypothesize that its expression in endometrial epithelium might promote sperm capacitation by maintaining the uterine environment. Yet, the mechanism of regulation has not been clarified. In this study, we investigated the expression of aldose reductase in mouse endometrial epithelium and its potential role in sperm capacitation. We initially investigated the periodic characteristics of glucose, fructose and sorbitol in uterine fluid. We then studied the temporal and spatial characteristics of aldose reductase in the endometrial epithelium. Next, we examined the effect of aldose reductase on glucose, fructose and sorbitol in uterine fluid. Finally, we explored the effect of aldose reductase on sperm capacitation and fertilization. The results showed that glucose and fructose content in uterine fluid and the expression of aldose reductase fluctuated periodically during physiological periods. Inhibition of aldose reductase in the endometrial epithelium interfered with sperm capacitation and fertilization by reducing the fructose levels in the uterine fluid. To conclude, the aldose reductase-mediated polyol pathway in endometrial epithelial cells is essential to maintain an appropriate fructose environment in the uterine fluid for sperm capacitation and fertilization.

Physiological and pathological roles of locally expressed kisspeptin and KISS1R in the endometrium.

Kisspeptins, encoded by the KISS1 gene, are a family of polypeptides that bind the kisspeptin receptor (KISS1R) to perform biological functions. Produced mainly in the hypothalamus, these neuropeptides regulate the pulsatile secretion of GnRH and trigger the hypothalamus-pituitary-gonadal axis. Other peripheral organs also express kisspeptin, which inhibits metastasis. Kisspeptin and KISS1R are reportedly present in the endometrium and may play roles in limiting the migration and invasion of trophoblasts into the endometrium during pregnancy (decidua) to maintain endometrial homeostasis. A deficiency of kisspeptin and KISS1R in the endometrium can lead to pathological conditions such as endometriosis and endometrial carcinoma. Kisspeptin and KISS1R in the endometrium can also promote endometrial receptivity and decidualization. Overall, kisspeptin and KISS1R are important for maintaining the normal physiological functions of the endometrium. By summarizing the roles of kisspeptin and KISS1R in the endometrium, our review explores the regulatory roles in the peripheral reproductive system of this peptide family that plays broad and profound roles in many physiological processes.

PCSK9 involves in the high-fat diet-induced abnormal testicular function of male mice.

In brief: Impaired spermatogenesis resulting from disturbed cholesterol metabolism due to intake of high-fat diet (HFD) has been widely recognized, however, the role of preprotein invertase subtilin 9 (PCSK9), which is a negative regulator of cholesterol metabolism, has never been reported. This study aims to reveal the role of PCSK9 on spermatogenesis induced by HFD in mice. Abstract: Long-term consumption of a high-fat diet (HFD) is an important factor that leads to impaired spermatogenesis exhibiting poor sperm quantity and quality. However, the mechanism of this is yet to be elucidated. Disrupted cholesterol homeostasis is one of many crucial pathological factors which could contribute to impaired spermatogenesis. As a negative regulator of cholesterol metabolism, preprotein invertase subtilin 9 (PCSK9) mediates low density lipoprotein receptor (LDLR) degradation to the lysosome, thereby reducing the expression of LDLR on the cell membrane and increasing serum low-density lipoprotein cholesterol level, resulting in lipid metabolism disorders. Here, we aim to study whether PCSK9 is a pathological factor for impaired spermatogenesis induced by HFD and the underlying mechanism. To meet the purpose of our study, we utilized wild-type C57BL/6 male mice and PCSK9 knockout mice with same background as experimental subjects and alirocumab, a PCSK9 inhibitor, was used for treatment. Results indicated that HFD induced higher PCSK9 expression in serum, liver, and testes, and serum PCSK9 is negatively correlated with spermatogenesis, while both PCSK9 inhibitor treatment and PCSK9 knockout methodologies ameliorated impaired lipid metabolism and spermatogenesis in mice fed a HFD. This could be due to the overexpression of PCSK9 induced by HFD leading to dyslipidemia, resulting in testicular lipotoxicity, thus activating the Bcl-2-Bax-Caspase3 apoptosis signaling pathway in testes, particularly in Leydig cells. Our study demonstrates that PCSK9 is an important pathological factor in the dysfunction of spermatogenesis in mice induced by HFD. This finding could provide innovative ideas for the diagnosis and treatment of male infertility.

Hyperandrogen-induced polyol pathway flux increase affects ovarian function in polycystic ovary syndrome via excessive oxidative stress.

AIMS: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in the women of childbearing age. It is characterized by hyperandrogenism and abnormal follicular growth and ovulation. The polyol pathway is a glucose metabolism bypass pathway initiated by aldose reductase (ADR). Androgen induces the expression of ADR in the male reproductive tract, which has a general physiological significance for male reproductive function. Here we investigate whether hyperandrogenemia in PCOS leads to increased flux of the polyol pathway in ovarian tissue, which in turn affects follicular maturation and ovulation through oxidative stress. MAIN METHODS: We used clinical epidemiological methods to collect serum and granulosa cells from clinical subjects for a clinical case-control study. At the same time, cell biology and molecular biology techniques were used to conduct animal and cell experiments to further explore the mechanism of hyperandrogen-induced ovarian polyol pathway hyperactivity and damage to ovarian function. KEY FINDINGS: Here, we find that hyperandrogenism of PCOS can induce the expression of ovarian aldose reductase, which leads to the increase of the polyol pathway flux, and affects ovarian function through excessive oxidative stress. SIGNIFICANCE: Our research has enriched the pathological mechanism of PCOS and may provide a new clue for the clinical treatment of PCOS.

Consistency and synchronization of AMPK-glycogen in endometrial epithelial cells are critical to the embryo implantation.

Uterine receptivity to the embryo is crucial for successful implantation. The establishment of uterine receptivity requires a large amount of energy, and abnormal energy regulation causes implantation failure. Glucose metabolism in the endometrium is tissue specific. Glucose is largely stored in the form of glycogen, which is the main energy source for the endometrium. AMP-activated protein kinase (AMPK), an important energy-sensing molecule, is a key player in the regulation of glucose metabolism and its regulation is also tissue specific. However, the mechanism of energy regulation in the endometrium for the establishment of uterine receptivity remains to be elucidated. In this study, we aimed to investigate the energy regulation mechanism of mouse uterine receptivity and its significance in embryo implantation. The results showed that the AMPK, p-AMPK, glycogen synthase 1, and glycogen phosphorylase M levels and the glycogen content in mouse endometrial epithelium varied in a periodic manner under regulation by the ovarian hormone. Specifically, progesterone significantly activated AMPK, promoted glycogenolysis, and upregulated glycogen phosphorylase M expression. AMPK regulated glycogen phosphorylase M expression and promoted glycogenolysis. AMPK was also found to be activated by changes in the energy or glycogen of the endometrial epithelial cells. The inhibition of AMPK activity or glycogenolysis altered the uterine receptivity markers during the window of implantation and ultimately interfered with implantation. In summary, consistency and synchronization of AMPK and glycogen metabolism constitute the core regulatory mechanism in mouse endometrial epithelial cells involved in the establishment of uterine receptivity.

Activation of SGLT3a in endometrial epithelial cells induces paracrine stromal cell decidualization.

Endometrial epithelial cells (EECs) and stromal cells (ESCs) have a close functional association. During the peri-implantation period, EECs with enhanced functional activities secrete a variety of paracrine factors to promote the decidualization of ESCs. However, little is known about the specific process by which EECs secrete paracrine factors to induce the decidualization of ESCs. Some evidence suggests that the activation of sodium-glucose cotransporter 3a (SGLT3a) induces the depolarization of ESCs to affect their function. Therefore, SGLT3a acts as a sensor molecule in certain cell types. In this study, the expression of SGLT3a was investigated in EECs to determine whether its levels increased during the peri-implantation period in female mice. The activation of SGLT3a in mouse EECs induced Na+ -dependent depolarization of the cell membrane and an influx of extracellular Ca2+ , which further promoted the expression and release of the paracrine factors prostaglandin E2 (PGE2) and F2-alpha (PGF2α) by upregulating the expression of cyclooxygenase-2. In turn, PGE2 and PGF2α induced the decidualization of ESCs. Importantly, we identified SGLT3a as a key molecule involved in the cross-talk between EECs and ESCs during the process of uterine decidualization.

Contribution of high-fat diet-induced PCSK9 upregulation to a mouse model of PCOS is mediated partly by SREBP2.

The incidence of polycystic ovary syndrome (PCOS) due to high-fat diet (HFD) consumption has been increasing significantly. However, the mechanism by which a HFD contributes to the pathogenesis of PCOS has not been elucidated. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key protein that regulates cholesterol metabolism. Our previous study revealed abnormally high PCSK9 levels in serum from patients with PCOS and in serum and hepatic and ovarian tissues from PCOS model mice, suggesting that PCSK9 is involved in the pathogenesis of PCOS. However, the factor that induces high PCSK9 expression in PCOS remains unclear. In this study, Pcsk9 knockout mice were used to further explore the role of PCSK9 in PCOS. We also studied the effects of a HFD on the expression of PCSK9 and sterol regulatory element-binding protein 2 (SREBP2), a regulator of cholesterol homeostasis and a key transcription factor that regulates the expression of PCSK9, and the roles of these proteins in PCOS pathology. Our results indicated HFD may play an important role by inducing abnormally high PCSK9 expression via SREBP2 upregulation. We further investigated the effects of an effective SREBP inhibitor, fatostain, and found that it could reduce HFD-induced PCSK9 expression, ameliorate hyperlipidemia and improve follicular development in PCOS model mice. Our study thus further elucidates the important role of an HFD in the pathogenesis of PCOS and provides a new clue in the prevention and treatment of this disorder.

Expression of SGLT1 in the Mouse Endometrial Epithelium and its Role in Early Embryonic Development and Implantation.

Many functional activities of endometrium epithelium are energy consuming which are very important for maintaining intrauterine environment needed by early embryonic development and establishment of implantation window. Glucose is a main energy supplier and one of the main components of intrauterine fluid. Obviously, glucose transports in endometrium epithelium involve in for these activities but their functions have not been elucidated. In this research, we observed a spatiotemporal pattern of sodium glucose transporter 1 (SGLT1) expression in the mouse endometrium. We also determined that progesterone can promote the expression of SGLT1 in the mouse endometrial epithelium in response to the action of oestrogen. Treatment with the SGLT1 inhibitor phlorizin or small interfering RNA specific for SGLT1 (SGLT1-siRNA) altered glucose uptake in primary cultured endometrial epithelial cells, which exhibited reduced ATP levels and AMPK activation. The injection of phlorizin or SGLT1-siRNA into one uterine horn of each mouse on day 2 of pregnancy led to an increased glucose concentration in the uterine fluid and decreased number of harvested normal blastocysts and decreased expression of integrin αVß3 in endometrial epithelium and increased expression of mucin 1 and lactoferrin in endometrial epithelium and the uterine homogenates exhibited activated AMPK, a decreased ATP level on day 4, and a decreased number of implantation sites on day 5. In embryo transfer experiments, pre-treatment of the uterine horn with phlorizin or SGLT1-siRNA during the implantation window led to a decreased embryo implantation rate on day 5 of pregnancy, even when embryos from normal donor mice were used. In conclusion, SGLT1, which participates in glucose transport in the mouse endometrial epithelium, inhibition and/or reduced expression of SGLT1 affects early embryo development by altering the glucose concentration in the uterine fluid. Inhibition and/or reduced expression of SGLT1 also affects embryo implantation by influencing energy metabolism in epithelial cells, which consequently influences implantation-related functional activities.

GLUT4 in Mouse Endometrial Epithelium: Roles in Embryonic Development and Implantation.

GLUT4 is involved in rapid glucose uptake among various kinds of cells to contribute to glucose homeostasis. Prior data have reported that aberrant glucose metabolism by GLUT4 dysfunction in the uterus could be responsible for infertility and increased miscarriage. However, the expression and precise functions of GLUT4 in the endometrium under physiological conditions remain unknown or controversial. In this study, we observed that GLUT4 exhibits a spatiotemporal expression in mouse uterus on pregnant days 1-4; its expression especially increased on pregnant day 4 during the window of implantation. We also determined that estrogen, in conjunction with progesterone, promotes the expression of GLUT4 in the endometrial epithelium in vivo or in vitro. GLUT4 is an important transporter that mediates glucose transport in endometrial epithelial cells (EECs) in vitro or in vivo. In vitro, glucose uptake decreased in mouse EECs when the cells were treated with GLUT4 small interfering RNA (siRNA). In vivo, the injection of GLUT4-siRNA into one side of the mouse uterine horns resulted in an increased glucose concentration in the uterine fluid on pregnant day 4, although it was still lower than in blood, and impaired endometrial receptivity by inhibiting pinopode formation and the expressions of leukemia inhibitory factor (LIF) and integrin ανß3, finally affecting embryonic development and implantation. Overall, the obtained results indicate that GLUT4 in the endometrial epithelium affects embryo development by altering glucose concentration in the uterine fluid. It can also affect implantation by impairing endometrial receptivity due to dysfunction of GLUT4.

Intrauterine administration of peripheral blood mononuclear cells activated by human chorionic gonadotropin in patients with repeated implantation failure: A meta-analysis.

The purpose of this study was to assess whether intrauterine administration of peripheral blood mononuclear cells (PBMCs) activated by human chorionic gonadotropin (hCG) could improve the pregnancy and live birth rates in women with repeated implantation failure (RIF), and whether the parameters of co-culture of hCG and PBMCs would affect the clinical outcomes. Six databases (PubMed, Ovid, Medline, NCBI, Cqvip and Wanfang) were searched up to October 2020 by two independent reviewers. Seven studies were included according to specific inclusion and exclusion criteria. A meta-analysis showed that the pregnancy and live birth rates were significantly increased in the case group compared with the control group (odds ratio [OR]: 3.43, 95 % confidence interval [CI]: 1.78-6.61; P = 0.0002 and OR: 2.79, 95 % CI: 1.09-7.15; P = 0.03), especially when hCG was cultured with PBMCs for 48 h or PBMCs administration was performed two or three days before embryo transfer (ET). Neither the dosage of the hCG co-cultured with PBMCs nor the mean concentration of the administered PBMCs appeared to influence the therapeutic efficiency. In conclusion, intrauterine administration of PBMCs co-cultured with hCG for 48 h, conducted two or three days before ET, could be an effective therapy for women experiencing RIF. Due to the limitations of sample size and quality of the included studies, further high-quality studies with large sample sizes are warranted to optimize the parameters of hCG and PBMC co-culture to help more RIF patients benefit from this therapy.

Serum kisspeptin levels in polycystic ovary syndrome: A meta-analysis.

AIM: To clarify the association of serum kisspeptin levels in women with polycystic ovary syndrome (PCOS) by meta-analysis. METHODS: Two English databases and two Chinese databases were searched for the relationship between kisspeptin and PCOS published from 2009. After the studies screening according to specific principles, we used STATA 12.0 for meta-analysis. Standardized mean difference (SMD) and its 95% confidence intervals (95% CIs) were used as the effect size and STATA 12.0 software was performed by this meta-analysis. RESULTS: Nine articles were included in the end, with a total of 1282 participants (699 patients and 583 controls). Heterogeneity between studies was statistically significant. Therefore, the random effects model was used to combine the effects. Meta-analysis showed statistically significant differences in serum kisspeptin levels between the PCOS patients and controls (SMD = 0.57, 95% CI [0.32, 0.82]), which indicated that there is a strong association between serum kisspeptin levels and PCOS. The source of high heterogeneity between the inclusion studies (I2  = 73.2%) might be due to the small sample size. The larger variation of kisspeptin concentration might be caused by different diagnosis criteria of PCOS and short half-time period of kisspeptin combined with nonstandard testing process. CONCLUSION: Serum kisspeptin levels in PCOS patients were higher than non-PCOS patients. It is a hint to indicate us that kisspeptin might be an independent biomarker of PCOS patients.

The Effects of Altered Endometrial Glucose Homeostasis on Embryo Implantation in Type 2 Diabetic Mice.

Type 2 diabetes mellitus (T2DM) is a disease characterized by hyperglycemia resulting from insulin resistance. In recent years, the incidence of T2DM has been increasing. Women with T2DM often suffer from infertility and early miscarriage; however, the underlying mechanisms remain unclear. Insulin is the most important regulatory hormone of glycogen metabolism. In addition, 5' adenosine monophosphate-activated protein kinase (AMPK) is an important regulator of glycogen metabolism. Patients with T2DM have inhibited AMPK expression in the liver, which leads to impaired glucose metabolism. However, the role of AMPK in endometrial glycogen metabolism has not been reported. In this study, a mouse model of T2DM was established to investigate whether altered endometrial glucose metabolism affects early embryo implantation. Metformin and insulin were used for therapy; the resulting changes to glycogen metabolism and embryo implantation were examined. The results indicate that the concentrations of glycogen decreased significantly in T2DM mice, resulting in insufficient energy supplies for proper endometrial function, and thereby impeding embryonic implantation. Interestingly, endometrial AMPK was not found to be overactivated. Insulin treatment was found to partially resolve the embryo implantation defects in T2DM mice. Metformin improved blood glucose but did not have a significant effect on local endometrial glucose metabolism. This study explored the changes in endometrial glucose metabolism in T2DM mouse, and the effects of these changes on embryo implantation. We found that insulin, but not metformin, significantly resolved embryo implantation problems. These findings will help to increase our understanding of the pathomechanisms of infertility and early miscarriage in women with T2DM.

Changes in Expression of Follicular Glucose Transporters May Be Involved in Ovarian Function Impairment during Diabetic Hyperglycemia.

Diabetes-induced hyperglycemia has a direct damaging effect on ovarian function. Despite its deadly impact on ovaries, the mechanism of this condition has not been fully elucidated. Glucose transporters are involved in glucose uptake and utilization. Many transporters have been detected in the ovaries, but their roles in diabetes-induced ovarian impairment are still unclear. In this study, the goal is to analyze glucose transporter expression in the ovarian follicles of type 1 diabetes mellitus patients and determine their roles within ovarian function impairment. The ovarian function of a mouse model of type 1 diabetes mellitus was evaluated by observing its estrus cycle, follicular development, and ovulation. Subtypes of the glucose transporter (GLUT2, GLUT3, GLUT4, SGLT1, and SGLT2), adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated AMPK (Thr172) were found to be simultaneously present in follicle cells. Compared with nondiabetic control mice, the diabetic mice showed a dysregulated estrus cycle and a significantly higher number of abnormal ova. Furthermore, the expression of multiple glucose transporters was lower than that of phosphorylated AMPK. Phosphorylated AMPK possessed more follicular granulosa cells and oocytes of diabetic mice than in those of the control mice. These results suggest that diabetes-induced hyperglycemia reduces the capability of ovarian follicle cells by downregulating glucose transporter expression, causing decreased glucose uptake and energy deprivation. This impact can potentially impair egg maturation and ovulation.

Role of PCSK9 in lipid metabolic disorders and ovarian dysfunction in polycystic ovary syndrome.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a critical role in the cholesterol metabolism by negatively regulating the low-density lipoprotein receptor (LDLR). Lipid metabolic and ovarian disorders are the common clinical manifestation of polycystic ovary syndrome (PCOS). Here, we intended to elucidate the role of PCSK9 in the pathogenesis of PCOS conducted on a human population in case-control design and animal part in an interventional study. METHODS: We firstly investigated the serum levels of PCSK9 in 46 PCOS patients compared with 49 healthy women as controls, and then developed a PCOS mouse model induced by dehydroepiandrosterone (DHEA) and a high-fat diet (HFD) to determine the role of PCSK9 in abnormal lipid metabolism and ovarian dysfunction of PCOS in four groups (n = 40 per group): control, PCOS mice, PCOS plus alirocumab group, and PCOS plus vehicle group. The expression of PCSK9 in their serum, hepatic and ovarian tissues, serum lipid profiles and hormones were measured. Additionally, mRNA and protein expression levels of LDLR in hepatic and ovarian tissues, ovarian morphology and function were determined. Finally, we used freshly isolated theca-interstitial cells (TICs) and granulosa cells (GCs) from prepubertal normal mice to explore the effect of PCSK9 on LDL uptake of the cells. RESULTS: Serum PCSK9 concentrations were higher in PCOS patients than normal controls (P < 0.05). The PCOS model mice exhibited significantly increased serum levels of total cholesterol (TC), LDL-C and high-density lipoprotein-cholesterol (HDL-C; P < 0.001, P < 0.001, P = 0.0004, respectively). Moreover, the serum PCSK9 protein level was significantly increased in PCOS mice (P = 0.0002), which positively correlated with serum LDL-C (r = 0.5279, P = 0.0004) and TC (r = 0.4151, P = 0.035). In both liver and ovary of PCOS mice, PCSK9 mRNA and protein levels were significantly increased (P < 0.05), but LDLR levels were significantly decreased (P < 0.05). Furthermore, alirocumab inhibiting PCSK9 partly increased in LDLR expression in both liver and ovary in PCOS mice, also ameliorated the lipid metabolic disorders and pathological changes of ovarian morphology and function and serum reproductive hormones but not in the PCOS plus vehicle group. In vitro experiment, recombinant PCSK9 decreased LDL uptake in TICs and GCs (P < 0.001, P = 0.0011, respectively), which were partly reversed by alirocumab (P < 0.001, P = 0.012, respectively). CONCLUSION: Abnormal high expression of PCSK9 in the blood, liver and ovary may be involved in the pathogenesis of PCOS by affecting lipid metabolism and ovarian function, and the inhibition of PCSK9 may partly reverse the pathological changes of PCOS. Our research suggests a possibility of PCSK9 as a new attractive target for diagnosis and treatment of PCOS.

Progesterone-induced miR-152 interferes with embryonic implantation by downregulating GLUT3 in endometrial epithelium.

To investigate the role of progesterone-induced micro-RNA (miR)-152 in early embryonic development and implantation by regulating GLUT3 in endometrial epithelium, qRT-PCR was used to detect the expression of miR-152, GLUT1, and GLUT3 in the endometrial epithelial cells of female mice. GLUT1 and GLUT3 proteins were detected by immunohistochemical staining in the mouse endometrial epithelium. Bioinformatics prediction associated with a luciferase assay was performed to determine whether GLUT1 and GLUT3 are target genes of miR-152. Specific miR-152 mimics or inhibitors were transfected into the endometrial epithelial cells to, respectively, overexpress or downregulate miR-152. Next, the glucose concentration of uterine fluid was measured by conducting high-performance liquid chromatography in vivo, and the glucose uptake of the endometrial epithelial cells was observed using a fluorometric assay in vitro. Early embryonic development and implantation were also observed after the miR-152 mimics or inhibitors had been transfected. Embryo transfer was observed after the miR-152 mimic transfection. miR-152 was found to directly target and thereby downregulate GLUT3 expression. The expressions of both miR-152 and GLUT3 in the mouse endometrial epithelium had spatiotemporal characteristics on days 1-4 of pregnancy. miR-152 affected the glucose concentration of uterine fluid and the glucose uptake of endometrial epithelial cells. The transfection of specific miR-152 mimics led to impaired embryonic development and implantation. To conclude, in endometrial epithelial cells, progesterone-induced miR-152 downregulates GLUT3 at the posttranscriptional level to maintain a proper glucose concentration in the uterine fluid, which is necessary for early embryonic development and implantation.

Progesterone-Induced miR-145/miR-143 Inhibits the Proliferation of Endometrial Epithelial Cells.

Our previous study showed that progesterone (P4) can specifically regulate the expression of some microRNAs (miRNAs) in endometrial epithelium. In the present study, we verified the P4-dependent expression of miR-145/miR-143 in endometrial epithelial cells, explored the regulative mechanism of the P4 receptor (PR), and investigated their effects on the proliferation of endometrial epithelial cells. Our results showed that P4 can induce the expression of miR-145/143 in endometrial epithelial cells by acting on the PR A subtype. P4-induced miR-145/143 can inhibit the expression of cyclin D2 by binding to cyclin D2 mRNA 3'UTR. It can also inhibit cell proliferation in mouse endometrial epithelium by arresting the cell cycle during the G1-S checkpoint. Furthermore, miR-145 and miR-143 can inhibit the proliferation of human endometrial cancer cells. In conclusion, P4-induced miR-145/miR-143 is an important regulator in the proliferation of endometrial epithelial cells, and it can also inhibit the proliferation of human endometrial cancer cells. Our study indicates miRNAs are important mechanism of P4 in inhibiting the proliferation of endometrial epithelial cells. And these miRNAs are potential candidates for the diagnosis of endometrial cancer and therapeutic targets.

The association between the environmental endocrine disruptor bisphenol A and polycystic ovary syndrome: a systematic review and meta-analysis.

OBJECTIVE: To investigate the association between bisphenol A (BPA) and polycystic ovary syndrome (PCOS). METHODS: A systematic review and meta-analysis using STATA software for observational studies. RESULTS: Nine studies involving 493 PCOS patients and 440 controls were included in this review. The meta-analysis demonstrated that PCOS patients had significantly higher BPA levels compared with control groups (standardized mean difference (SMD): 2.437, 95% confidence interval (CI): (1.265, 3.609), p < .001). For studies of serum samples detected by enzyme-linked immunosorbent assay (ELISA), subgroup analyses according to ethnicity, body mass index (BMI), sample size, detection method (high-performance liquid chromatography (HPLC) and ELISA), PCOS-to-control ratio and study quality displayed that high BPA levels were significantly associated with Caucasian PCOS patients (SMD: 0.615, 95% CI: (0.308, 0.922), p < .001), high BMI (SMD: 0.512, 95% CI: (0.180, 0.843), p = .002), high quality (SMD: 0.624, 95% CI: (0.391, 0.856), p < .001), and high HOMA-IR (SMD: 0.467, 95% CI: (0.121, 0.813), p = .008). CONCLUSIONS: Serum BPA may be positively associated with women with PCOS and BPA might be involved in the insulin-resistance and hyperandrogenism of PCOS. More evidence from high quality studies, advanced detection methods, and larger cohorts for observational trials are needed to further confirm the association between BPA and PCOS.

Bisphenol A Initiates Excessive Premature Activation of Primordial Follicles in Mouse Ovaries via the PTEN Signaling Pathway.

The essence of primary ovarian insufficiency (POI) is the premature exhaustion of primordial follicles in the follicle pool, which is caused by the excessive premature activation of primordial follicles after birth. Bisphenol A (BPA) exposure promotes the transition of primordial follicles to primary follicles, thus the number of primordial follicles in the primordial follicle pool decreases significantly. However, the molecular mechanisms underlying abnormal follicle activation are poorly understood. Phosphatase and tensin homologue (PTEN) signal system is a negative regulator of follicle activation, which is called the brake of follicle activation. Besides, BPA induces Michigan Cancer Foundation-7 breast cancer cells proliferation by dysregulating PTEN/serine/threonine kinase/p53 axis. Whether BPA initiates the excessive premature activation of primordial follicles in the mouse ovaries via PTEN signaling pathway is unclear. In this study, we treated 6-week-old female CD-1 mice with different concentrations of BPA to study the effect of BPA on follicular activation and development in vivo, as well as the role of PTEN signaling in this process. We observed that BPA in concentrations from 1 µg/kg to 10 mg/kg groups downregulated PTEN expression and initiated excessive premature activation of primordial follicles in the mouse ovaries, and this effect was partly reversible by PTEN overexpression. Our results improve the understanding of both the effect of BPA in occurrence of POI and molecular mechanisms underlying initiation of primordial follicle pool activation, thus providing insight for POI treatment and theoretical basis for reducing the risk of POI.