Carbon Black Nanoparticles Inhibit Aromatase Expression and Estradiol Secretion in Human Granulosa Cells Through the ERK1/2 Pathway

Zingiberis rhizoma-based carbon dots alter serum oestradiol and follicle-stimulating hormone levels in female mice

Chinese herbs contain substances that regulate female hormones. Our study confirmed that Zingiberis rhizoma carbonisata contains Zingiberis rhizoma-based carbon dots (ZR-CDs), which exert regulatory effects on serum oestradiol and FSH in mice and show impacts on endometrial growth and follicular development that potentially affect the ability of female fertility. ZR-CDs were characterized to clarify the microstructure, optical features, and functional group characteristics. It shows that ZR-CDs are spherical carbon nanostructures ranging from 0.97 to 2.3 nm in diameter, with fluorescent properties and a surface rich in functional groups. We further investigated the impact of ZR-CDs on oestradiol and FSH in serum, growth, and the development of ovarian and uterine using normal female mice and exogenous oestradiol intervention model. It was observed that ZR-CDs accelerated oestrogen metabolism and attenuated oestradiol-induced endometrial hyperplasia. Simultaneously, ZR-CDs triggered an increase in FSH, even in the presence of high-serum oestradiol that inhibits FSH secretion. Our findings suggest that ZR-CDs could be a potential therapeutic treatment for anovulatory menstruation.

Excessive fluoride induces ovarian function impairment by regulating levels of ferroptosis in fluorosis women and ovarian granulosa cells

The aim of this study was to investigate the role of ferroptosis in fluorosis women and the in vitro molecular mechanisms leading to ovarian dysfunction and abnormal hormone secretion by sodium fluoride (NaF) treatment of KGN cells. Fifty women with fluorosis as Fluorosis group and fifty healthy women as Control group were included in this study. The levels of lipid peroxidation and activities of antioxidant enzyme were assessed by photometric methods. The content of iron and glutathione (GSH) in serum was measured by microplate method. KGN cells were treated by different concentration of NaF (0, 1, 2, 4 and 8 ×10-3 M) for 24 h. The mRNA and protein expression levels of ferroptosis-related molecules, including glutathione peroxidase 4 (GPX4), solute carrier family 7 member (SLC7A11), nuclear factor erythroid 2-related factor 2 (Nrf2), ferritin heavy chain 1 (FTH1) and p53, were assessed by qRT-PCR and western blot analysis. Fluorosis group women had a significant higher levels of iron, Malondialdehyde (MDA), FSH and LH, and a lower levels of E2 and antioxidant enzyme in serum than that in the control group. The representative molecular changes of ferroptosis, such as the decrease in GPX4, Nrf2 and SLC7A11 expression (mRNA and protein expression), the increase in protein expression of p53, and a reduced level of E2 were observed in KGN cells treated by excessive NaF.It is concluded therefore that NaF increases the expression of p53 and inhibits ovarian granulosa cell ferroptosis preventive protein expression, resulting in abnormal hormone secretion and the ovarian dysfunction.

Ambient black carbon particles in human ovarian tissue and follicular fluid

Evidence indicates a link between exposure to ambient air pollution and decreased female fertility. The ability of air pollution particles to reach human ovarian tissue and follicles containing the oocytes in various maturation stages has not been studied before. Particulate translocation might be an essential step in explaining reproductive toxicity and assessing associated risks. Here, we analysed the presence of ambient black carbon particles in (i) follicular fluid samples collected during ovum pick-up from 20 women who underwent assisted reproductive technology treatment and (ii) adult human ovarian tissue from 5 individuals. Follicular fluid and ovarian tissue samples were screened for the presence of black carbon particles from ambient air pollution using white light generation by carbonaceous particles under femtosecond pulsed laser illumination. We detected black carbon particles in all follicular fluid (n = 20) and ovarian tissue (n = 5) samples. Black carbon particles from ambient air pollution can reach the ovaries and follicular fluid, directly exposing the ovarian reserve and maturing oocytes. Considering the known link between air pollution and decreased fertility, the impact of such exposure on oocyte quality, ovarian ageing and fertility needs to be clarified urgently.

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.

3D Microtissues Mimic the Architecture, Estradiol Synthesis, and Gap Junction Intercellular Communication of the Avascular Granulosa

Humans are consistently exposed to thousands of untested chemicals that have been detected in the follicular fluid of the ovaries, and can disrupt reproductive health. Human granulosa cells (GCs) are the functional unit of the ovarian follicle with steroidogenic and signaling activities, and play a pivotal role in oocyte development. During follicle progression, GCs multiply to form a 3D avascular structure, and establish gap junction intercellular communication (GJIC) that is critical to maintaining optimal viability and function. We developed a high-throughput in vitro platform of human GCs for the screening of chemicals that can impact GJIC and estradiol (E2) production of human granulosa. Our granulosa 3D microtissues fabricated with human ovarian granulosa-like tumor KGN cells are multicell-layered structures that mimic the avascular granulosa layers surrounding the oocyte. These microtissues robustly expressed the steroidogenic CYP19 aromatase enzyme and GJIC intercellular membrane channel, connexin 43. Granulosa microtissues produced E2 at rates comparable to primary human GCs as previously reported. E2 production was suppressed by the CYP19 inhibitor, letrozole, and induced by CYP19 activators, bisphenol A at 100 µM, and genistein at 100 µM. Granulosa microtissues displayed active GJIC function, as demonstrated by the connexin 43-dependent diffusion of calcein fluorescent dye from microtissue surface to the core using high-throughput confocal microscopy in conjunction with our open-sourced automated image analysis tool. Overall, our 3D human granulosa screening platform is highly promising for predictive and efficient in vitro toxicity testing to screen for chemicals that contaminate follicular fluid and may affect fertility.

Carbon Black Nanoparticles Selectively Alter Follicle-Stimulating Hormone Expression in vitro and in vivo in Female Mice

Toxic effects of nanoparticles on female reproductive health have been documented but the underlying mechanisms still need to be clarified. Here, we investigated the effect of carbon black nanoparticles (CB NPs) on the pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are key regulators of gonadal gametogenesis and steroidogenesis. To that purpose, we subjected adult female mice to a weekly non-surgical intratracheal administration of CB NPs at an occupationally relevant dose over 4 weeks. We also analyzed the effects of CB NPs in vitro, using both primary cultures of pituitary cells and the LβT2 gonadotrope cell line. We report here that exposure to CB NPs does not disrupt estrous cyclicity but increases both circulating FSH levels and pituitary FSH β-subunit gene (Fshb) expression in female mice without altering circulating LH levels. Similarly, treatment of anterior pituitary or gonadotrope LβT2 cells with increasing concentrations of CB NPs dose-dependently up-regulates FSH but not LH gene expression or release. Moreover, CB NPs enhance the stimulatory effect of GnRH on Fshb expression in LβT2 cells without interfering with LH regulation. We provide evidence that CB NPs are internalized by LβT2 cells and rapidly activate the cAMP/PKA pathway. We further show that pharmacological inhibition of PKA significantly attenuates the stimulatory effect of CB NPs on Fshb expression. Altogether, our study demonstrates that exposure to CB NPs alters FSH but not LH expression and may thus lead to gonadotropin imbalance.

Advances in endocrine toxicity of nanomaterials and mechanism in hormone secretion disorders

The size of nanoparticles is about 1-100 nm. People are exposed to nanoparticles in environmental pollutants from ancient times to the present. With the maturity of nanotechnology in the past two decades, the production of manufactured nanomaterials is rapidly increasing and they are used in a wide range of aerospace, medicine, food, and industrial applications. However, both natural and manufactured nanomaterials have been proved to pose a threat to diverse organs and systems. The endocrine system is critical to maintaining homeostasis. Endocrine disorders are associated with many diseases, including cancer, reduced fertility, and metabolic diseases. Therefore, we review the literatures dealing with the endocrine toxicity of nanomaterial. This review provides an exhaustive description of toxic effects of several common nanomaterials in the endocrine system; more involved are reproductive endocrinology. Then physicochemical factors that determine the endocrine toxicity of nanomaterials are discussed. Furthermore, oxidative stress, changes in steroid production and metabolic enzymes, organelle disruption, and alterations in signal pathways are introduced as potential mechanisms that may cause changes in hormone levels. Finally, we suggest that a risk assessment of endocrine toxicity based on standard procedures and consideration of endocrine disrupting effects of nanomaterials in the field and its environmental and population effects could be future research directions for endocrine toxicity of nanomaterials.

Ovarian toxicity of nanoparticles

The ovary is a highly important organ for female reproduction. The main functions include sex steroid hormone synthesis, follicular development, and achievement of oocyte meiotic and development competence for proper fertilization. Nanoparticle (NP) exposure is becoming unavoidable because of its wide use in different products, including cosmetics, food, health, and personal care products. Studies examining different nonreproductive tissues or systems have shown that characteristics such as the size, shape, core material, agglomeration, and dissolution influence the effects of NPs. However, most studies evaluating NP-mediated reproductive toxicity have paid little or no attention to the influence of the physicochemical characteristics of NP on the observed effects. As accumulating evidence indicates that NP may reach the ovary to impair proper functions, this review summarizes the available data on NP accumulation in ovarian tissue, as well as data describing toxicity to ovarian functions, including sex steroid hormone production, follicular development, oocyte quality, and fertility. Due to their toxicological relevance, this review also describes the main physicochemical characteristics involved in NP toxicity and the importance of considering NP physicochemical characteristics as factors influencing the ovarian toxicity of NPs. Finally, this review summarizes the main mechanisms of toxicity described in ovarian cells.

Ovariectomy reduces the cardiac cytoprotection in rats exposed to particulate air pollutant

Fine particulate matter (PM_2.5) has been considered a risk factor for cardiovascular diseases by inducing an oxidative and inflammatory phenotype. Besides, the reduction of 17β-estradiol (E2) levels during menopause is a natural risk for cardiovascular outcomes. During the E2 downfall, there is a high requirement of the 70-kDa heat shock proteins (HSP70), which present essential antioxidant, anti-inflammatory, and anti-senescence roles. We investigated if the ovariectomy, an animal model for menopause, could induce additional effects in cardiac health by impairing oxidative and heat shock response parameters of female rats chronically exposed to residual oil fly ash (ROFA; an inorganic fraction of PM_2.5). Thus, ROFA was obtained from São Paulo (Brazil) and solubilized it in saline. Further, female Wistar rats were exposed to 50 μL of saline (control group) or ROFA solution (250 μg) (polluted) by intranasal instillation, 5 days/week, 12 weeks. At the 12th week, animals were subdivided into four groups (n = 6 p/group): control, OVX, polluted, and polluted + OVX. Control and polluted were submitted to false surgery, while OVX and polluted + OVX were ovariectomized. ROFA or saline exposure continued for 12 weeks. Ovariectomy reduced the cardiac catalase activity and iHSP70 expression in female rats exposed to ROFA. Neither plasma eHSP72 levels nor H-index (eHSP72 to cardiac iHSP70 ratio) was affected. In conclusion, ovariectomy reduces the cardiac cytoprotection and antioxidant defense, and enhances the susceptibility to premature cellular senescence in rats exposed to ROFA.

Estrogen disorders: Interpreting the abnormal regulation of aromatase in granulosa cells (Review)

Ovarian granulosa cells (GCs) are the most important source of estrogen. Therefore, aromatase (estrogen synthase), which is the key enzyme in estrogen synthesis, is not only an important factor of ovarian development, but also the key to estrogen secretion by GCs. Disorders of the ovarian estrogen secretion are more likely to induce female estrogen-dependent diseases and fertility issues, such as ovarian cancer and polycystic ovary syndrome. Hence, aromatase is an important drug target; treatment with its inhibitors in estrogen-dependent diseases has attracted increasing attention. The present review article focuses on the regulation and mechanism of the aromatase activity in the GCs, as well as the specific regulation of aromatase promoters. In GCs, follicle-stimulating hormone (FSH) is dependent on the cyclic adenosine monophosphate (cAMP) pathway to regulate the aromatase activity, and the regulation of this enzyme is related to the activation of signaling pathways, such as phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK). In addition, endocrine-disrupting substance and other related factors affect the expression of aromatase, which eventually create an imbalance in the estrogen secretion by the target tissues. The present review highlights these useful factors as potential inhibitors for target therapy.

Endocrine Disruption of the Follicle-Stimulating Hormone Receptor Signaling During the Human Antral Follicle Growth

An increasing number of pollutants with endocrine disrupting potential are accumulating in the environment, increasing the exposure risk for humans. Several of them are known or suspected to interfere with endocrine signals, impairing reproductive functions. Follicle-stimulating hormone (FSH) is a glycoprotein playing an essential role in supporting antral follicle maturation and may be a target of disrupting chemicals (EDs) likely impacting female fertility. EDs may interfere with FSH-mediated signals at different levels, since they may modulate the mRNA or protein levels of both the hormone and its receptor (FSHR), perturb the functioning of partner membrane molecules, modify intracellular signal transduction pathways and gene expression. In vitro studies and animal models provided results helpful to understand ED modes of action and suggest that they could effectively play a role as molecules interfering with the female reproductive system. However, most of these data are potentially subjected to experimental limitations and need to be confirmed by long-term observations in human.

Ovariectomy enhances female rats' susceptibility to metabolic, oxidative, and heat shock response effects induced by a high-fat diet and fine particulate matter

Obesity and exposure to fine particulate matter (air pollutant PM_2.5) are important risk factors for metabolic and cardiovascular diseases. They are also related to early menopause. The reduction of 17β-estradiol (E2) levels during female climacteric, marked by menopause, is of significant concern because of its imminent influence on metabolism, redox and inflammatory status. This complex homeostasis-threatening scenario may induce a heat shock response (HSR) in cells, enhancing the expression of the 70 kDa heat shock protein (HSP70). A failure in this mechanism could predispose women to cardiovascular diseases. In this study, we evaluated if the climacteric could represent an additional risk among obese rats exposed to PM_2.5 by worsening lipid, oxidative, and inflammatory parameters and HSP70 in cardiac tissue. We induced obesity in female Wistar rats using a high-fat diet (HFD) (58.3% as fats) and exposed them to 50 μL of saline 0.9% (control, n = 15) or 250 μg residual oil fly ash (ROFA, the inorganic portion of PM_2.5) (polluted, n = 15) by intranasal instillation, 5 days/w for 12 weeks. At the 12th week, we subdivided these animals into four groups: control (n = 6), OVX (n = 9), polluted (n = 6) and polluted + OVX (n = 9). OVX and polluted + OVX were submitted to a bilateral ovariectomy (OVX), a surgical model for menopause, while control and polluted received a false surgery (sham). ROFA exposure and HFD consumption were continued for 12 additional weeks, after which the animals were euthanized. ROFA enhanced the susceptibility to ovariectomy-induced dyslipidemia, while ovariectomy predisposed female rats to the ROFA-induced decrease of cardiac iHSP70 expression. Ovariectomy also decreased the IL-6 levels and IL-6/IL-10 in obese animals, reinforcing a metabolic impairment and a failure to respond to unfavorable conditions. Our results support the hypothesis that obese ovariectomized animals are predisposed to a metabolic worsening under polluted conditions and are at higher risk of cardiovascular diseases.

Possible role of C60 fullerene in the induction of reproductive toxicity in the freshwater fish, Anabas testudineus (Bloch, 1792)

In recent years, the impact of ultrafine nanomaterials on the aquatic organisms and their ecosystems contributed much concern due to their abundance in environment. Several toxicity studies have reported that nanoparticles induced reproductive stress and resulted in reproductive impairment of fishes. The present study was aimed to investigate the stress-induced toxicity of C₆₀ fullerene nanomaterial on various reproductive parameters of the freshwater fish, Anabas testudineus. Fish were exposed to two sublethal concentrations of fullerene C₆₀, one-tenth (5 mg/L) and one-fifth (10 mg/L) of LC₅₀-96 h, for 4, 7, 15, 30, and 60-day durations. At the end of exposure period, the activities of steroidogenic enzymes, 3β-, and 17β-hydroxysteroid dehydrogenase decreased in the testis and ovary thereby indicated that the nanomaterial affected gonadal steroidogenesis. The level of serum testosterone decreased significantly (p < 0.05) in male whereas the level of estradiol showed significant (p < 0.05) reduction in female fish with significant (p < 0.05) increase in the level of serum cortisol in both sexes in concentration- and time-dependent manner. The analysis of the levels of alkali-labile phosphates, plasma calcium, and total protein showed significant (p < 0.05) reduction in female fish without significant changes in male fish, and this could be due to the antiestrogenic action of fullerene C₆₀ nanomaterial. The activity of aromatase enzyme decreased significantly (p < 0.05) in the ovary and brain of female fish, and the decline in the enzyme activity was prominent only in the brain tissue of male fish. The present results suggested that the stress-induced by fullerene C₆₀ exposure provoked reproductive toxicity in the fish, Anabas testudineus.

Can atmospheric pollutants influence menstrual cycle function?

A few experimental studies suggest that atmospheric pollutants could affect the endocrine system, and in particular stress hormones and the hypothalamic-hypophyseal-ovarian axis, which could in turn influence menstrual cycle function. We aimed to study the possible short-term effects of atmospheric pollutants on the length of the follicular and luteal phases and on the duration of the menstrual cycle in humans. To do so, from a nation-wide study on couples' fecundity, we recruited 184 women not using contraception who collected urine samples at least every other day during one menstrual cycle, from which a progesterone metabolite was assayed, allowing estimation of the duration of the follicular and luteal phases of the cycle. Atmospheric pollution (nitrogen dioxide and particulate matter with an aerodynamical diameter below 10 μm, PM₁₀) levels were estimated from a dispersion model with a 1-km resolution combined with permanent monitoring stations measurements, allowing to estimate exposures in the 30-day, 1-10 and 11-30-day periods before the start of the menstrual cycle. Regression models allowed to quantify the change in cycle duration associated with atmospheric pollutants and adjusted for potential confounders. Follicular phase duration increased on average by 0.7 day (95% confidence interval, CI, 0.2; 1.3) for each increase by 10 μg/m³ in NO₂ concentration averaged over the 30 days before the cycle and by 1.6 day (95% CI, 0.3; 2.9) for each increase by 10 μg/m³ in PM₁₀. There was no strong evidence of associations of exposures in this time window with luteal phase or with total menstrual cycle durations (p > 0.2). Exposures in the 1-10 day period before the cycle start were also associated with increased follicular phase duration. This study is one of the first prospective studies to suggest short-term alterations in follicular phase duration following atmospheric pollutants exposure.

Human cytochrome P450 enzymes 5-51 as targets of drugs and natural and environmental compounds: mechanisms, induction, and inhibition - toxic effects and benefits

Cytochrome P450 (P450, CYP) enzymes have long been of interest due to their roles in the metabolism of drugs, pesticides, pro-carcinogens, and other xenobiotic chemicals. They have also been of interest due to their very critical roles in the biosynthesis and metabolism of steroids, vitamins, and certain eicosanoids. This review covers the 22 (of the total of 57) human P450s in Families 5-51 and their substrate selectivity. Furthermore, included is information and references regarding inducibility, inhibition, and (in some cases) stimulation by chemicals. We update and discuss important aspects of each of these 22 P450s and questions that remain open.

Methods for Evaluation of Ovarian Granulosa Cells with Exposure to Nanoparticles

Increasing evidence demonstrates that a substantial number of chemicals including nanoparticles have potential toxic effects on human and wildlife reproductive health. Ovarian granulosa cells (GCs), the functional unit of the ovary, play a pivotal role in the regulation of ovarian reproductive health in females. They are considered to be the main target by the chemicals at all stages of their development. It has been reported that nanoparticles induced toxicity of GCs by interfering with cell cycle. Some basic methods for evaluation of GCs with exposure to nanoparticles are described in this chapter including isolation of GCs, determination of apoptosis by immunofluorescence, and measurement of progesterone level by ELISA.