Estrogen Physiology Research Articles

UNRAVELING NONGENOMIC MECHANISMS BY WHICH 17Α-ESTRADIOL EXTENDS HEALTHSPAN AND LONGEVITY

Abstract Recent work indicates that exogenous 17α-estradiol (17α-E2), a stereoisomer of 17β-E2, produces unprecedented longevity increases (~20%) in male mice, challenging prevailing assumptions that 17α-E2 is a weak estrogen. However, is unclear how 17α-E2 acts. Therefore, this study aimed to obtain mechanistic insights into 17α-E2 actions in the uterus, the most widely used vivo model system for estrogen action. We hypothesized that 17α-E2 signals through membrane (m)ESR1 to affect target tissues and promote longevity. To test this, we treated pre-pubertal (postnatal day 20) female CD-1 mice with 3 daily IP injections of vehicle or 10 mg/kg of 17α-E2 or 17β-E2 (n=4/group). 17α-E2 treatment did not significantly increase uterine weight – a marker of nuclear (n)ESR1 signaling (20.3 ± 2.1 mg vs. vehicle 15.7 ± 2.0 mg, p>0.05), while 17β-E2 strongly increased it to 41.4 ± 1.1 mg (p<0.05). Accordingly, histological analysis revealed reduced cell proliferation in 17α-E2- vs. 17β-E2-treated uteri. Both 17α-E2 and 17β-E2 robustly stimulated epithelial p-ERK and p-AKT expression, the active phosphorylated forms of these protein kinases, and western blotting showed a strong and comparable stimulation of EZH2, a critical mediator of estrogen’s epigenetic effects, which are linked to mESR1 signaling. In conclusion, our results indicate that despite limited actions through nESR1, 17α-E2 robustly signals through mESR1 to activate uterine protein kinase cascades and produce epigenetic effects. These findings may cause a significant reappraisal of 17α-E2 biological effects and role in normal estrogen physiology and provide critical insights into its unique ability to stimulate longevity.

UNRAVELING NONGENOMIC MECHANISMS BY WHICH 17A-ESTRADIOL EXTENDS HEALTHSPAN AND LONGEVITY

Abstract Recent work indicates that exogenous 17α-estradiol (17α-E2), a stereoisomer of 17β-E2, produces unprecedented longevity increases (~20%) in male mice, challenging prevailing assumptions that 17α-E2 is a weak estrogen. However, is unclear how 17α-E2 acts. Therefore, this study aimed to obtain mechanistic insights into 17α-E2 actions in the uterus, the most widely used vivo model system for estrogen action. We hypothesized that 17α-E2 signals through membrane (m)ESR1 to affect target tissues and promote longevity. To test this, we treated pre-pubertal (postnatal day 20) female CD-1 mice with 3 daily IP injections of vehicle or 10 mg/kg of 17α-E2 or 17β-E2 (n=4/group). 17α-E2 treatment did not significantly increase uterine weight – a marker of nuclear (n)ESR1 signaling (20.3 ± 2.1 mg vs. vehicle 15.7 ± 2.0 mg, p>0.05), while 17β-E2 strongly increased it to 41.4 ± 1.1 mg (p< 0.05). Accordingly, histological analysis revealed reduced cell proliferation in 17α-E2- vs. 17β-E2-treated uteri. Both 17α-E2 and 17β-E2 robustly stimulated epithelial p-ERK and p-AKT expression, the active phosphorylated forms of these protein kinases, and western blotting showed a strong and comparable stimulation of EZH2, a critical mediator of estrogen’s epigenetic effects, which are linked to mESR1 signaling. In conclusion, our results indicate that despite limited actions through nESR1, 17α-E2 robustly signals through mESR1 to activate uterine protein kinase cascades and produce epigenetic effects. These findings may cause a significant reappraisal of 17α-E2 biological effects and role in normal estrogen physiology and provide critical insights into its unique ability to stimulate longevity.

Practical aspects of laboratory monitoring of estrogens in men

Since the discovery of estrogens in the 30s of the XX century, scientific and practical interest in them has been concentrated exclusively from the standpoint of female endocrinology, and the physiology and pathophysiology of estrogens in men, due to the historically established interpretation of the role of these steroids exclusively as female sex hormones, have remained practically unexplored for a long time. However, according to the classical theory of steroidogenesis, estrogens are the end product of this biochemical process, and testosterone, in addition to its well-known independent functions in the male body, also acts as their biochemical precursor. Therefore, normal endocrinology of sex steroids in men is in principle impossible without the participation of estrogens, and over the past decades, convincing scientific data have been accumulated indicating important physiological functions of estrogens in the male body. The review article, based on the literature of recent years, briefly examines the key aspects of clinical endocrinology of estrogens in men and describes in more detail the modern possibilities of methods for laboratory monitoring of estrogens in blood serum in men and some diagnostic tools that allow a more complete and objective interpretation of the results of laboratory methods for determining estrogens, in particular, testosterone/estradiol ratio. It is shown that the calculation of this ratio is a more reliable method for assessing estrogen metabolism disorders in routine clinical practice than the separate determination of serum levels of sex steroids, and can be considered as an important marker of various diseases in men.

Segregation of nuclear and membrane-initiated actions of estrogen receptor using genetically modified animals and pharmacological tools

Estrogen receptor alpha (ERα) and beta (ERβ) are members of the nuclear receptor superfamily, playing widespread functions in reproductive and non-reproductive tissues. Beside the canonical function of ERs as nuclear receptors, in this review, we summarize our current understanding of extra-nuclear, membrane-initiated functions of ERs with a specific focus on ERα. Over the last decade, in vivo evidence has accumulated to demonstrate the physiological relevance of this ERα membrane-initiated-signaling from mouse models to selective pharmacological tools. Finally, we discuss the perspectives and future challenges opened by the integration of extra-nuclear ERα signaling in physiology and pathology of estrogens.

Adrenal-permissive HSD3B1 genetic inheritance and risk of estrogen-driven postmenopausal breast cancer.

10503 Background: Genetic factors that contribute to endogenous estrogen synthesis and postmenopausal breast cancer risk are unknown. We set out to test the hypothesis that homozygous inheritance of the common 1245A→C missense-encoding polymorphism in HSD3B1, which is common (8-10%) in White populations, functionally adrenal permissive and increases synthesis of the aromatase substrate, androstenedione, is associated with postmenopausal estrogen receptor-positive breast cancer. Methods: A prospective single institution study of postmenopausal estrogen receptor-driven breast cancer for determination of HSD3B1 genotype, circulating steroid concentrations, and adrenal-permissive genotype frequency compared with the genotype frequency in the general population and in estrogen receptor-negative breast cancer. Validation was performed in 2 breast cancer genomic studies with estrogen receptor documentation. The primary outcome is the adrenal-permissive genotype frequency in postmenopausal estrogen receptor-positive breast cancer and the general population. Genotype comparisons were also done with postmenopausal estrogen receptor-negative breast cancer and the association with circulating adrenal androgen concentrations determined. Results: The prospective and validation studies had 199 and 1628 women, respectively. The adrenal-permissive genotype frequency in postmenopausal White women with estrogen-driven breast cancer in the prospective cohort was 17.5% (21/120) compared with 9.6% (429/4451) in the general population [p = 0.0077]. The adrenal-permissive genotype frequency for estrogen-driven postmenopausal breast cancer was validated using the Cambridge and TCGA genomic datasets together: 14.4% (56/389) compared with 6.0% (9/149) for estrogen receptor-negative breast cancer (p = 0.007) and the general population (p = 0.005). Circulating androstenedione concentration was significantly higher for women with the adrenal-permissive genotype compared with the other genotypes (p = 0.03). Conclusions: The adrenal-permissive genotype is associated with estrogen-driven postmenopausal breast cancer. These findings link genetic inheritance of endogenous estrogen exposure to estrogen-driven breast cancer and have broad implications for risk stratification, prevention, potential biomarkers for hormonal therapy response and possibly other clinical outcomes related to estrogen physiology in postmenopausal women.

Therapeutic Perspectives on the Modulation of G-Protein Coupled Estrogen Receptor, GPER, Function.

Estrogens exert their physiological and pathophysiological effects via cellular receptors, named ERα, ERβ, and G-protein coupled estrogen receptor (GPER). Estrogen-regulated physiology is tightly controlled by factors that regulate estrogen bioavailability and receptor sensitivity, while disruption of these control mechanisms can result in loss of reproductive function, cancer, cardiovascular and neurodegenerative disease, obesity, insulin resistance, endometriosis, and systemic lupus erythematosus. Restoration of estrogen physiology by modulating estrogen bioavailability or receptor activity is an effective approach for treating these pathological conditions. Therapeutic interventions that block estrogen action are employed effectively for the treatment of breast and prostate cancer as well as for precocious puberty and anovulatory infertility. Theoretically, treatments that block estrogen biosynthesis should prevent estrogen action at ERs and GPER, although drug resistance and ligand-independent receptor activation may still occur. In addition, blockade of estrogen biosynthesis does not prevent activation of estrogen receptors by naturally occurring or man-made exogenous estrogens. A more complicated scenario is provided by anti-estrogen drugs that antagonize ERs since these drugs function as GPER agonists. Based upon its association with metabolic dysregulation and advanced cancer, GPER represents a therapeutic target with promise for the treatment of several critical health concerns facing Western society. Selective ligands that specifically target GPER have been developed and may soon serve as pharmacological agents for treating human disease. Here, we review current forms of estrogen therapy and the implications that GPER holds for these therapies. We also discuss existing GPER targeted drugs, additional approaches towards developing GPER-targeted therapies and how these therapies may complement existing modalities of estrogen-targeted therapy.

Genome-Wide Analysis of Low Dose Bisphenol-A (BPA) Exposure in Human Prostate Cells.

Endocrine disrupting compounds (EDCs) have the potential to cause adverse effects on wild-life and human health. Two important EDCs are the synthetic estrogen 17α-ethynylestradiol (EE2) and bisphenol-A (BPA) both of which are xenoestrogens (XEs) as they bind the estrogen receptor and dis-rupt estrogen physiology in mammals and other vertebrates. In the recent years the influence of XEs on oncogenes, specifically in relation to breast and prostate cancer has been the subject of considerable study.Methodology: In this study, healthy primary human prostate epithelial cells (PrECs) were exposed to environmentally relevant concentrations of BPA (5nM and 25nM BPA) and interrogated using a whole genome microarray.Results: Exposure to 5 and 25nM BPA resulted in 7,182 and 7,650 differentially expressed (DE) genes, respectively in treated PrECs. Exposure to EE2 had the greatest effect on the PrEC transcriptome (8,891 DE genes).Conclusion: We dissected and investigated the nature of the non-estrogenic gene signature associated with BPA with a focus on transcripts relevant to epigenetic modifications. The expression of transcripts encoding nuclear hormone receptors as well as histone and DNA methylation, modifying enzymes were significantly perturbed by exposure to BPA.

Androgenic deficiency and its impact on women`s health status

The review analyzes the current state of the problem of androgen deficiency in the female body. The features of androgens synthesis, metabolism, and impact on woman`s reproductive organs and the state of the organism as a whole are discussed. The methods of examining the homeostasis of androgens, their advantages and disadvantages are shown. The state of the problem of hypo-androgenic conditions in women of the perimenopausal and postmenopausal age, as well as the possibility of correcting the androgen deficiency in these categories of women is highlighted. In general, the features of the physiology of estrogens and progesterone have been well studied by modern science, at the same time, new fundamental research and clinical trials are needed to study the role of androgens in order to comprehensive study the role of these hormones in women of different ages. Thus, to date, not all aspects of the correction of sexual dysfunction of the female population of different age groups have been resolved. To study the role of androgens in restoring the hormonal balance of the female body, new fundamental research is needed

Del Editor sobre la Terapia hormonal de reemplazo para la prevención primaria de enfermedades crónicas – Borrador del documento de recomendación del Grupo de Trabajo de los Servicios de Prevención de los EE UU

En 16 de mayo de 2017, el Grupo de Trabajo de Servicios de Prevención de los EE UU solicitó comentarios a una declaración de recomendación y revisión de la evidencia sobre la terapia hormonal para la menopausia en la prevención primaria de enfermedades crónicas. Basado en la revisión de la evidencia, el Grupo de Trabajo hace la recomendación contra el uso combinado de estrógeno y progestágeno para la prevención de condiciones crónicas en las mujeres posmenopáusicas. A partir de este documento, se realiza una breve consideración sobre la fisiología hormonal estrogénica durante la menopausia y las recomendaciones subsecuentes por instituciones especializadas sobre la terapia hormonal con estrógenos y progestágenos para la prevención de la sintomatología crónica cardiovascular, vasomotora, neurológica y osteoporótica.

Sex and longevity: Why women live longer than men.

Sex differences in lifespan exist in most countries in the world, with women outliving men. This difference has existed for as long as records have been kept. This gap is not a uniquely human phenomenon; it exists in many animals as well. This is an important health issue that is not fully understood. Aging is a complex process. In this review we will examine the scientific basis for sex differences by focusing on four hypotheses that begin with examining why women are different from men. Men and women differ in our DNA. Women have two X chromosomes and men have an X and Y sex chromosome. Women have a second copy of the genes on the X chromosome which could be protective. Other hypotheses focus on the physiological difference between the sexes that result from the ratio of our sex hormones. Estrogen physiology changes women’s body shape, affects the major organs like the heart and as a result impacts longevity. Sex differences in longevity are important because this becomes a lens for us to examine nutrition, health and wellness.

Brain Estrogens and Feeding Behavior.

Estrogens play essential roles in suppressing food intake and preventing body weight gain. Tremendous research efforts have been focused on estrogen physiology in the context of feeding control. Estrogen receptors and the related signals have been attractive targets for development of new obesity therapies. This chapter focuses on the functional interactions between brain estrogens and other appetite-regulatory signals, the critical estrogen receptor isoforms and distinct brain regions that mediate effects of estrogens on feeding, and the intracellular signals that are involved.

Progress in the molecular understanding of central regulation of body weight by estrogens.

ObjectiveEstrogens can act in the brain to prevent body weight gain. Tremendous research efforts have been focused on estrogen physiology in the brain in the context of body weight control; estrogen receptors and the related signals have been attractive targets for development of new obesity therapies. The objective is to review recent findings in these aspects.MethodsWe reviewed recent studies, primarily from those using the conventional and conditional knockout mouse strains, regarding the cellular and molecular mechanisms for the beneficial effects of estrogens on body weight balance. We also discuss emerging genetic tools that could further benefit the field of estrogen research, and newly developed estrogen-based regimen that produce body weight-lowering benefits.ResultsThe body weight-lowering effects of estrogens are mediated by multiple forms of estrogen receptors, in different brain regions through distinct but coordinated mechanisms. Both rapid signals and “classic” nuclear receptor actions of estrogen receptors appear to contribute to estrogenic regulation on body weight.ConclusionEstrogen receptors and associated signal networks are potential targets for obesity treatment, and further investigations are warranted.

The role of estrogens at men. Part 1. General and developmental endocrinology, physiology and pathophysiology of estrogens at men

The role of estrogens at men. Part 1. General and developmental endocrinology, physiology and pathophysiology of estrogens at men

Expanding the structural footprint of xenoestrogens

Many synthetic chemicals with structural similarity to estradiol bind to the estrogen receptor and disrupt the normal estrogen physiology in humans and other vertebrates. Most of these xenoestrogens contain a structure that mimics the phenolic A ring on E2. This phenolic A ring is a defining property of E2 that distinguishes it from aldosterone, cortisol, progesterone and testosterone. However, Δ5-androstenediol, 5α-androstanediol and 27-hydroxy-cholesterol also have estrogenic activity, despite having important structural differences in their A rings compared to E2. Unlike E2, these steroids have a saturated A ring with a 3β-hydroxyl and a C19 methyl group. An implication of their estrogenic activity is that synthetic chemicals containing a saturated A ring with a 3β-hydroxyl and a C19 methyl group are potential xenoestrogens.

Aberrant Synthesis, Metabolism, and Plasma Accumulation of Circulating Estrogens and Estrogen Metabolites in Preeclampsia Implications for Vascular Dysfunction

Estrogens and estrogen metabolites have important functions in cardiovascular and other physiology, yet the patterns of estrogen synthesis, metabolism, and the individual plasma profile of estrogens and estrogen metabolites during human pregnancy as well as in preeclampsia remain undetermined. We performed liquid chromatography mass spectrometry on plasma samples from normotensive pregnant women (normP; n=8), women with mild (mPE; n=8), and severe (sPE; n = 8) preeclampsia at labor. Compared with normP, estrone was lower in sPE, whereas plasma level of estradiol-17β was significantly lower in women with mPE and sPE. Estriol was lower in sPE, but not in mPE. Although 2-hydroxyestrone was lower in mPE and sPE, 4-hydroxyestrone was high in sPE. 16-α-hydroxyestrone was higher in mPE, but not in sPE. 2-hydroxyestradiol in women with mPE and sPE were lower compared with normP. Compared with 2-methoxyestrone in normP, levels were lower in sPE. 3-methoxyestrone and 4-methoxyestrone were unchanged. 2-methoxyestradiol was lower in mPE and sPE; however, 4-methoxyestradiol was low only in sPE. Compared with normP, 16-keto-estradiol-17β levels were significantly higher in sPE, whereas 16-epi-estriol and 17-epi-estriol were lower in women with sPE. Our findings show that preeclampsia is characterized by aberrant synthesis, metabolism, and accumulation of estrogens and estrogen metabolites that are likely to be associated with alterations in vascular function. These results underscore the need to investigate the functional vascular and other physiology of estrogens and estrogen metabolites in the pathophysiology of preeclampsia.

3D Models of MBP, a Biologically Active Metabolite of Bisphenol A, in Human Estrogen Receptor α and Estrogen Receptor β

Bisphenol A [BPA] is a widely dispersed environmental chemical that is of much concern because the BPA monomer is a weak transcriptional activator of human estrogen receptor α [ERα] and ERβ in cell culture. A BPA metabolite, 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene [MBP], has transcriptional activity at nM concentrations, which is 1000-fold lower than the concentration for estrogenic activity of BPA, suggesting that MBP may be an environmental estrogen. To investigate the structural basis for the activity of MBP at nM concentrations and the lower activity of BPA for human ERα and ERβ, we constructed 3D models of human ERα and ERβ with MBP and BPA for comparison with estradiol in these ERs. These 3D models suggest that MBP, but not BPA, has key contacts with amino acids in human ERα and ERβ that are important in binding of estradiol by these receptors. Metabolism of BPA to MBP increases the spacing between two phenolic rings, resulting in contacts between MBP and ERα and ERβ that mimic those of estradiol with these ERs. Mutagenesis of residues on these ERs that contact the phenolic hydroxyls will provide a test for our 3D models. Other environmental chemicals containing two appropriately spaced phenolic rings and an aliphatic spacer instead of an estrogenic B and C ring also may bind to ERα or ERβ and interfere with normal estrogen physiology. This analysis also may be useful in designing novel chemicals for regulating the actions of human ERα and ERβ.

Genes regulating estradiol and estrone-conjugate levels in postmenopausal women with resected early-stage breast cancer detected by a genome-wide association study (GWAS).

1001 Background: There is large inter-individual variation in baseline estrone (E1), estradiol (E2), E1-conjugate (E1-C), androstenedione (A), and testosterone (T) levels in postmenopausal women with resected early stage breast cancer (Ingle et al., Ca Res 70:3278−86, 2010). We hypothesized that genetic variation can explain some of this variation in baseline (before anastrozole) hormone levels and performed a GWAS. Methods: Baseline plasma was obtained for E1, E2, E1-C, A, and T assays by GC-MS-MS. Genotypes were determined with the Illumina Human610-Quad BeadChip. Eigenstrat analyses were performed to control for population stratification (PS). Analysis of each baseline hormone level was assessed with each genotype using a quasi-likelihood model because of the skewness in baseline hormone levels, with adjustment for PS as well as body mass index, age and any additional clinical variables associated with baseline hormone levels (p<0.01). SNPs were imputed within 200 Kb on either side of regions containing SNPs with p < 3E-05 using HapMap. Results: 563,945 SNPs were used in the analyses. SNP genotypes were modeled in terms of the number of minor alleles (0, 1 or 2), with SNPs achieving genome-wide significance after Bonferroni correction (p<5E-08) identified for both E2 and E1-C. For E2 (n=757 patients), the genotyped SNP (rs1864729) with the lowest p-value (p=1.13E-08) was on chromosome (chr) 8 and had a multiplicative effect (ME: estimated fold change per minor allele) of 1.62 (95% CI: 1.38, 1.91), with the closest gene being TSPYL5 (Testis-specific Y-encoded-like protein 5), which we showed to be regulated by E2. There were 8 imputed SNPs near rs1864729 with lower p-values (1.03E-08-3.85E-09). For E1-C (n=752 patients), one nonsynonymous SNP (rs4149056) on chr 12 in the SLCO1B1 gene (which encodes an E1-C transporter) was significant (p=5E-08) with ME 1.41 (95% CI: 1.25, 1.60). Conclusions: This GWAS revealed novel loci associated with the baseline levels of E2 and E1-C in postmenopausal women that may be of importance for understanding the estrogen physiology of postmenopausal women and their response to aromatase inhibitor therapy.

Need for research on estrogen receptor function: Importance for postmenopausal hormone therapy and atherosclerosis

Cardiovascular disease is the leading cause of morbidity and mortality in men and women worldwide. Although rare in premenopausal women, its incidence rises sharply after menopause, indicating atheroprotective effects of endogenous estrogens. This review discusses the differential effects of estrogen receptor function on atherosclerosis progression in pre- and postmenopausal women, including aspects of gender differences in vascular physiology of estrogens and androgens. Recent advances in the understanding of the pathogenesis of atherosclerosis, estrogen receptor function, and hormone therapy are reviewed, with particular emphasis on clinical and molecular issues. Whether hormone therapy can improve cardiovascular health in postmenopausal women remains controversial. Current evidence suggests that the vascular effects of estrogen are affected by the stage of reproductive life, the time since menopause, and the extent of subclinical atherosclerosis. The mechanisms of vascular responsiveness to sex steroids during different stages of atherosclerosis development remain poorly understood in women and men. In view of the expected increase in the prevalence of atherosclerotic vascular disease worldwide due to population aging, research is needed to determine the vascular mechanism of endogenous and exogenous sex steroids in patients with atherosclerosis. Such research may help to define new strategies to improve cardiovascular health in women and possibly also in men.

The Unexpected Science of Estrogen Receptor-β Selective Agonists: A New Class of Anti-Inflammatory Agents?

In the nine years since the unexpected discovery of a second form of the estrogen receptor (ER), ERβ has been mentioned in about 2,800 literature citations. Such prolific research is testimony to interest in explaining its role in estrogen physiology as well as investigating its potential as a drug target. Our current understanding is that ERα, not ERβ is responsible for mediating the effects of estrogens in “classic” model systems such as the reproductive tract and skeleton. The role of ERβ is still being defined, but profiling of ERβ selective agonists in several animal models of human disease indicates these compounds may have utility as novel anti-inflammatory agents. The challenge for the future is to elucidate their mechanism of action and determine the clinical relevance of the impressive preclinical observations.

A Transmembrane Intracellular Estrogen Receptor Mediates Rapid Cell Signaling

The steroid hormone estrogen regulates many functionally unrelated processes in numerous tissues. Although it is traditionally thought to control transcriptional activation through the classical nuclear estrogen receptors, it also initiates many rapid nongenomic signaling events. We found that of all G protein-coupled receptors characterized to date, GPR30 is uniquely localized to the endoplasmic reticulum, where it specifically binds estrogen and fluorescent estrogen derivatives. Activating GPR30 by estrogen resulted in intracellular calcium mobilization and synthesis of phosphatidylinositol 3,4,5-trisphosphate in the nucleus. Thus, GPR30 represents an intracellular transmembrane estrogen receptor that may contribute to normal estrogen physiology as well as pathophysiology.