Distinct Estrogen Receptor Research Articles

Distinct ER and PR expression patterns significantly affect the clinical outcomes of early HER2-positive breast cancer: A real-world analysis of 871 patients treated with neoadjuvant therapy

IntroductionThe impact of distinct estrogen receptor (ER) and progesterone receptor (PR) expression patterns on tumor behavior and treatment outcomes within HER2-positive breast cancer is not fully explored. This study aimed to comprehensively examine the clinical differences among patients with HER2-positive breast cancer harboring distinct ER and PR expression patterns in the neoadjuvant setting. MethodsThis retrospective analysis included 871 HER2-positive breast patients treated with neoadjuvant therapy at our hospital between 2011 and 2022. Comparisons were performed across the three hormone receptor (HR)-specific subtypes, namely the ER-negative/PR-negative/HER2-positive (ER-/PR-/HER2+), the single HR-positive (HR+)/HER2+, and the triple-positive breast cancer (TPBC) subtypes. ResultsOf 871 patients, 21.0% had ER-/PR-/HER2+ tumors, 33.6% had single HR+/HER2+ disease, and 45.4% had TPBC. Individuals with single HR+/HER2+ tumors and TPBC cases demonstrated significantly lower pathological complete response (pCR) rates compared to those with ER-/PR-/HER2+ tumors (36.9% vs. 24.3% vs. 49.2%, p < 0.001). Multivariate analysis confirmed TPBC as significantly associated with decreased pCR likelihood (OR = 0.42, 95%CI 0.28–0.63, p < 0.001). Survival outcomes, including disease-free survival (DFS) and overall survival (OS), showed no significant differences across HR-specific subtypes in the overall patient population. However, within patients without anti-HER2 therapy, TPBC was linked to improved DFS and a trend towards better OS. ConclusionsHER2-positive breast cancer exhibited three distinct HR-specific subtypes with varying clinical manifestations and treatment responses. These findings suggest personalized treatment strategies considering ER and PR expression patterns, emphasizing the need for further investigations to unravel molecular traits underlying HER2-positive breast cancer with distinct HR expression patterns.

Distribution of estrogen receptors alpha and beta in the brain of male rats with same-sex preference

Two distinct estrogen receptors (ERs) exist, ERα and ERβ. Both receptors participate in sexual differentiation of the rat brain and likely participate in the regulation of adult sexual orientation (i.e. partner preference). This last idea was investigated herein by examining males treated with the aromatase inhibitor, letrozole, administered prenatally (0.56 μg/kg G10–22). This treatment usually provokes same-sex preference in 1–2 males per litter. Vehicle-treated males (with female preference) and females in spontaneous proestrus (with male preference) were included as controls. ERα and ERβ expression was analyzed by immunohistochemistry in brain areas known to control masculine sexual behavior and partner preference, like the medial preoptic area (MPOA), bed nucleus of the stria terminalis (BNST), medial amygdala (MeA) and ventromedial hypothalamic nucleus (VMH), as well as other brain regions suspected to participate in these processes. In addition, serum levels of estradiol were determined in all male groups. Letrozole-treated male rats that preferred sexually experienced males (LPM) showed over-expressed ERα in the hippocampal cornu Ammonis (CA 1, 3, 4) and dentate gyrus. The LPM group showed up-regulated ERβ expression in the CA2 and reticular thalamic nucleus. The levels of estradiol did not differ between the groups. Higher expression of ERs in these males was different than their expression in females, with male sex-preference. This suggests that males with same-sex preference showed a unique brain, this sui generis steroid receptor expression probably participates in the biological underpinnings of sexual preference.

Distinct breast cancer phenotypes in BRCA 1/2 carriers based on ER status.

BRCA1/2 genes are the two main genes associated with hereditary breast cancers (BC). In the present study, we explore clinical and molecular characteristics of BRCA-associated BC in relation to estrogen receptor (ER) status. Three BC databases (DB) were evaluated: (i) Hadassah oncogenetics (n = 4826); (ii) METABRIC (n = 1980), and (iii) Nick-Zainal (n = 560). We evaluated age at diagnosis in BRCA positive (BP) and BRCA negative (BN) patients,and tested for mutational signature differences in cohort iii. mRNA differential expression analysis(DEA) and pathway analysis were performed in cohort ii. Age at diagnosis was lower in BP vs. BN tumors in all cohorts in the ER- group, and only in cohort i for the ER + group. Signature 3 was universal in BP BC, whereas several signatures were associated with ER status.Pathway analysis was performed between BP&BN, and was significant only in ER- tumors: the major activated pathways involved cancer-related processes and were highly significant. The most significant pathway was estrogen-mediated S-phase entry and the most activated upstream regulator was ERBB2. Signature 3 was universal for all BP BC, while other signatures were associated with ER status. ER + BP& BN show similar genomic characteristics, ER- BP differed markedly from BN. This suggests that the initial carcinogenic process is universal for all BRCA carriers, but further insults lead to the development of two genomically distinct subtypes ER- and ER + . This may shed light on possible mechanisms involved in BP and carry preventive and therapeutic implications.

Transcription factor-nucleosome dynamics from plasma cfDNA identifies ER-driven states in breast cancer.

Genome-wide binding profiles of estrogen receptor (ER) and FOXA1 reflect cancer state in ER+ breast cancer. However, routine profiling of tumor transcription factor (TF) binding is impractical in the clinic. Here, we show that plasma cell-free DNA (cfDNA) contains high-resolution ER and FOXA1 tumor binding profiles for breast cancer. Enrichment of TF footprints in plasma reflects the binding strength of the TF in originating tissue. We defined pure in vivo tumor TF signatures in plasma using ER+ breast cancer xenografts, which can distinguish xenografts with distinct ER states. Furthermore, state-specific ER-binding signatures can partition human breast tumors into groups with significantly different ER expression and mortality. Last, TF footprints in human plasma samples can identify the presence of ER+ breast cancer. Thus, plasma TF footprints enable minimally invasive mapping of the regulatory landscape of breast cancer in humans and open vast possibilities for clinical applications across multiple tumor types.

THE GOOD, BETTER AND BEST ABOUT SELECTIVE ESTROGEN RECEPTOR MODULATORS AS NOVEL GUARDIANS AGAINST OSTEOPOROSIS

The functions of estrogen are highly significant in human physiology. The regulatory effect of estrogen is mediated through three distinct estrogen receptors (ER), namely estrogen receptor alpha (ER α), estrogen receptor beta (ER β) and G protein coupled estrogen receptor (GPCER). Selective estrogen receptor modulators (SERMs) are synthetic/ natural molecules that aid in transcriptional roles such as estrogen agonistic / antagonist activity in target tissues by binding to ER. These compounds lack the steroidal back bone of estrogen but structurally resemble estrogen and hence can compete with estrogen and bind to estrogen responsive elements. This in turn triggers downstream signaling pathways that decide the fate of the cell to transit between proliferation and death. This review article describes the various synthetic and natural SERMS, their chemical classification, mechanism of action, side effects, bioavailability and clinical implications in several pathogenic conditions majorly in osteoporosis. This is based on a systematic review and consideration of the recent literature on various approaches (Pharmacogenomics, nutrigenomics, Pharmaconutritional approaches) on osteoporosis and strategies involved in the management of its clinical symptoms. Osteoporosis is a growing health burden all over the world, affecting the quality of life especially in elderly women population. Apart from the role of SERMs in osteoporosis, this review summarizes the promising roles of SERMs in other pathologic conditions like breast cancer, cardiovascular diseases, neuroprotection and reproductive biology. Hence the exploitation of SERMs as therapeutic and prophylactic agents with increased tolerability, safety and efficacy is an area of booming research in the recent decades.

Endogenous and Therapeutic Estrogens: Maestro Conductors of the Microenvironment of ER+ Breast Cancers.

Simple SummaryBreast cancers that express estrogen receptor alpha (ER+) are the most common subtype of breast cancers. Although surgery and anti-estrogen therapies are successful for most of these patients, treatment-resistant ER+ metastatic cancers account for the majority of breast-cancer-related deaths. Immunotherapies have shown promise for other cancer types, but these have been much less effective for ER+ breast cancers. In this review, we update progress in our understanding of the immune microenvironment and the community of other cells that surround ER+ cancer cells at the primary and metastatic sites, the responses of these different cell types to various anti-estrogen therapies, and the net outcomes in experimental and clinical studies. We highlight evolving technologies that will provide greater insight into the biology of ER+ breast cancer and the foundation for new treatment and prevention strategies, in order to reduce mortality of this disease.Estrogen receptor alpha (ERα) marks heterogeneous breast cancers which display a repertoire of somatic genomic mutations and an immune environment that differs from other breast cancer subtypes. These cancers also exhibit distinct biological behaviors; despite an overall better prognosis than HER2+ or triple negative breast cancers, disseminated dormant cells can lead to disease recurrence decades after the initial diagnosis and treatment. Estrogen is the best studied driver of these cancers, and antagonism or reduction of estrogen activity is the cornerstone of therapeutic approaches. In addition to reducing proliferation of ERα+ cancer cells, these treatments also alter signals to multiple other target cells in the environment, including immune cell subpopulations, cancer-associated fibroblasts, and endothelial cells via several distinct estrogen receptors. In this review, we update progress in our understanding of the stromal cells populating the microenvironments of primary and metastatic ER+ tumors, the effects of estrogen on tumor and stromal cells to modulate immune activity and the extracellular matrix, and net outcomes in experimental and clinical studies. We highlight new approaches that will illuminate the unique biology of these cancers, provide the foundation for developing new treatment and prevention strategies, and reduce mortality of this disease.

Estradiol 17-β Induces Pancreatic Beta-Cell Proliferation through Distinct Estrogen Receptors in a Glucose Dependent Manner

Background: Estradiol 17-beta (E2) enhances the function and survival of pancreatic beta-cells but its clinical use has been questioned due to concerns regarding oncogenic potential and feminizing effects in males. The G-protein coupled estrogen receptor (GPER), expressed in pancreatic islets, exhibits estrogenic beta-cell protective effects, without the feminizing effects of the nuclear ERs. Here, we examine the outcome of selective activation of the three estrogen receptors ERα, ERβ and GPER on replication, in human pancreatic islets and the INS1-E rodent β-cell line, under hyperglycemic conditions such as occur in diabetes mellitus. Methods: Pancreatic islets from nine human donors and INS1-E cells were grown at glucose concentrations of 11mM and 25mM and examined for DNA synthesis using 3[H]-thymidine incorporation, after 24 hour treatment with E2 and specific agonists for ERα, ERβ and GPER (PPT 10nM, DPN 10nM and G1 100nM, respectively). Expression of the three ERs was examined by qRT-PCR. Results: In human islets, under glucose 11mM, agonists to ERα and GPER induced a significant ~2 folds increase in 3[H]-thymidine incorporation (p

Neuroprotective and neurotrophic actions of estrogens on amyloid β synaptotoxicity are mediated by distinct estrogen receptors

Neuroprotective and neurotrophic actions of estrogens on amyloid β synaptotoxicity are mediated by distinct estrogen receptors

Cartilaginous Fishes Provide Insights into the Origin, Diversification, and Sexually Dimorphic Expression of Vertebrate Estrogen Receptor Genes.

Vertebrate estrogen receptors (ERs) perform numerous cell signaling and transcriptional regulatory functions. ERɑ (Esr1) and ERβ (Esr2) likely evolved from an ancestral receptor that duplicated and diverged at the protein and cis-regulatory levels, but the evolutionary history of ERs, including the timing of proposed duplications, remains unresolved. Here we report on identification of two distinct ERs in cartilaginous fishes and demonstrate their orthology to ERα and ERβ. Phylogenetic analyses place the ERα/ERβ duplication near the base of crown gnathostomes (jawed vertebrates). We find that ERα and ERβ from little skate (Leucoraja erinacea) and mammals share key subtype-specific residues, indicating conserved protein evolution. In contrast, jawless fishes have multiple non-orthologous Esr genes that arose by parallel duplications. Esr1 and Esr2 are expressed in subtype-specific and sexually dimorphic patterns in skate embryos, suggesting that ERs might have functioned in sexually dimorphic development before the divergence of cartilaginous and bony fishes.

17β-Estradiol Acutely Potentiates Glutamatergic Synaptic Transmission in the Hippocampus through Distinct Mechanisms in Males and Females

Estradiol (E2) acutely potentiates glutamatergic synaptic transmission in the hippocampus of both male and female rats. Here, we investigated whether E2-induced synaptic potentiation occurs via presynaptic and/or postsynaptic mechanisms and which estrogen receptors (ERs) mediate E2's effects in each sex. Whole-cell voltage-clamp recordings of mEPSCs in CA1 pyramidal neurons showed that E2 increases both mEPSC frequency and amplitude within minutes, but often in different cells. This indicated that both presynaptic and postsynaptic mechanisms are involved, but that they occur largely at different synapses. Two-photon (2p) glutamate uncaging at individual dendritic spines showed that E2 increases the amplitude of uncaging-evoked EPSCs (2pEPSCs) and calcium transients (2pCaTs) at a subset of spines on a dendrite, demonstrating synapse specificity of E2's postsynaptic effects. All of these results were essentially the same in males and females. However, additional experiments using ER-selective agonists indicated sex differences in the mechanisms underlying E2-induced potentiation. In males, an ERβ agonist mimicked the postsynaptic effects of E2 to increase mEPSC, 2pEPSC, and 2pCaT amplitude, whereas in females, these effects were mimicked by an agonist of G protein-coupled ER-1. The presynaptic effect of E2, increased mEPSC frequency, was mimicked by an ERα agonist in males, whereas in females, an ERβ agonist increased mEPSC frequency. Thus, E2 acutely potentiates glutamatergic synapses similarly in both sexes, but distinct ER subtypes mediate the presynaptic and postsynaptic aspects of potentiation in each sex. This indicates a latent sex difference in which different molecular mechanisms converge to the same functional endpoint in males versus females.SIGNIFICANCE STATEMENTSome sex differences in the brain may be latent differences, in which the same functional endpoint is achieved through distinct underlying mechanisms in males versus females. Here we report a latent sex difference in molecular regulation of excitatory synapses in the hippocampus. The steroid 17β-estradiol is known to acutely potentiate glutamatergic synaptic transmission in both sexes. We find that this occurs through a combination of increased presynaptic glutamate release probability and increased postsynaptic sensitivity to glutamate in both sexes, but that distinct estrogen receptor subtypes underlie each aspect of potentiation in each sex. These results indicate that therapeutics targeting a specific estrogen receptor subtype or its downstream signaling would likely affect synaptic transmission differently in the hippocampus of each sex.

Update on the therapeutic significance of estrogen receptor beta in malignant gliomas.

Malignant glioma is the most fatal of the astrocytic lineage tumors despite therapeutic advances. Men have a higher glioma incidence than women, indicating that estrogen level differences between men and women may influence glioma pathogenesis. However, the mechanism underlying the anticancer effects of estrogen has not been fully clarified and is complicated by the presence of several distinct estrogen receptor types and the identification of a growing number of estrogen receptor splice variants. Specifically, it is generally accepted that estrogen receptor alpha (ERα) functions as a tumor promoter, while estrogen receptor beta (ERβ) functions as a tumor suppressor, and the role and therapeutic significance of ERβ signaling in gliomas remains elusive. Thus, a deeper analysis of ERβ could elucidate the role of estrogens in gender-related cancer incidence. ERβ has been found to be involved in complex interactions with malignant gliomas. In addition, the prognostic value of ERβ expression in glioma patients should not be ignored when considering translating experimental findings to clinical practice. More importantly, several potential drugs consisting of selective ERβ agonists have exhibited anti-glioma activities and could further extend the therapeutic potential of ERβ-selective agonists. Here, we review the literature to clarify the anti-glioma effect of ERβ. To clarify ERβ-mediated treatment effects in malignant gliomas, this review focuses on the potential mechanisms mediated by ERβ in the intracellular signaling events in glioma cells, the prognostic value of ERβ expression in glioma patients, and various ERβ agonists that could be potential drugs with anti-glioma activities.

A ternary classification using machine learning methods of distinct estrogen receptor activities within a large collection of environmental chemicals.

Endocrine-disrupting chemicals (EDCs), which can threaten ecological safety and be harmful to human beings, have been cause for wide concern. There is a high demand for efficient methodologies for evaluating potential EDCs in the environment. Herein an evaluation platform was developed using novel and statistically robust ternary models via different machine learning models (i.e., linear discriminant analysis, classification and regression tree, and support vector machines). The platform is aimed at effectively classifying chemicals with agonistic, antagonistic, or no estrogen receptor (ER) activities. A total of 440 chemicals from the literature were selected to derive and optimize the three-class model. One hundred and nine new chemicals appeared on the 2014 EPA list for EDC screening, which were used to assess the predictive performances by comparing the E-screen results with the predicted results of the classification models. The best model was obtained using support vector machines (SVM) which recognized agonists and antagonists with accuracies of 76.6% and 75.0%, respectively, on the test set (with an overall predictive accuracy of 75.2%), and achieved a 10-fold cross-validation (CV) of 73.4%. The external predicted accuracy validated by the E-screen assay was 87.5%, which demonstrated the application value for a virtual alert for EDCs with ER agonistic or antagonistic activities. It was demonstrated that the ternary computational model could be used as a faster and less expensive method to identify EDCs that act through nuclear receptors, and to classify these chemicals into different mechanism groups.

A second estrogen receptor from Japanese lamprey (Lethenteron japonicum) does not have activities for estrogen binding and transcription

Estrogens regulate many physiological responses in vertebrates by binding to the estrogen receptor (ER), a ligand-activated transcription factor. To understand the evolution of vertebrate ERs and to investigate how estrogen acts in a jawless vertebrate, we used degenerate primer sets and PCR to isolate DNA fragments encoding two distinct ER subtypes, Esr1a and Esr1b from the Japanese lamprey, Lethenteron japonicum. Phylogenetic analysis indicates that these two ERs are the result of lineage-specific gene duplication within the jawless fishes, different from the previous duplication event of Esr1 (ERα) and Esr2 (ERβ) within the jawed vertebrates. Reporter gene assays show that lamprey Esr1a displays both constitutive and estrogen-dependent activation of gene transcription. Domain swapping experiments indicate that constitutive activity resides in the A/B domain of lamprey Esr1a. Unexpectedly, lamprey Esr1b does not bind estradiol and is not stimulated by other estrogens, androgens or corticosteroids. A 3D model of lamprey Esr1b suggests that although estradiol fits into the steroid binding site, some stabilizing contacts between the ligand and side chains that are found in human Esr1 and Esr2 are missing in lamprey Esr1b.

17β-Estradiol Acutely Potentiates Glutamatergic Synaptic Transmission in the Hippocampus through Distinct Mechanisms in Males and Females

Estradiol (E2) acutely potentiates glutamatergic synaptic transmission in the hippocampus of both male and female rats. Here, we investigated whether E2-induced synaptic potentiation occurs via presynaptic and/or postsynaptic mechanisms and which estrogen receptors (ERs) mediate E2's effects in each sex. Whole-cell voltage-clamp recordings of mEPSCs in CA1 pyramidal neurons showed that E2 increases both mEPSC frequency and amplitude within minutes, but often in different cells. This indicated that both presynaptic and postsynaptic mechanisms are involved, but that they occur largely at different synapses. Two-photon (2p) glutamate uncaging at individual dendritic spines showed that E2 increases the amplitude of uncaging-evoked EPSCs (2pEPSCs) and calcium transients (2pCaTs) at a subset of spines on a dendrite, demonstrating synapse specificity of E2's postsynaptic effects. All of these results were essentially the same in males and females. However, additional experiments using ER-selective agonists indicated sex differences in the mechanisms underlying E2-induced potentiation. In males, an ERβ agonist mimicked the postsynaptic effects of E2 to increase mEPSC, 2pEPSC, and 2pCaT amplitude, whereas in females, these effects were mimicked by an agonist of G protein-coupled ER-1. The presynaptic effect of E2, increased mEPSC frequency, was mimicked by an ERα agonist in males, whereas in females, an ERβ agonist increased mEPSC frequency. Thus, E2 acutely potentiates glutamatergic synapses similarly in both sexes, but distinct ER subtypes mediate the presynaptic and postsynaptic aspects of potentiation in each sex. This indicates a latent sex difference in which different molecular mechanisms converge to the same functional endpoint in males versus females. Some sex differences in the brain may be latent differences, in which the same functional endpoint is achieved through distinct underlying mechanisms in males versus females. Here we report a latent sex difference in molecular regulation of excitatory synapses in the hippocampus. The steroid 17β-estradiol is known to acutely potentiate glutamatergic synaptic transmission in both sexes. We find that this occurs through a combination of increased presynaptic glutamate release probability and increased postsynaptic sensitivity to glutamate in both sexes, but that distinct estrogen receptor subtypes underlie each aspect of potentiation in each sex. These results indicate that therapeutics targeting a specific estrogen receptor subtype or its downstream signaling would likely affect synaptic transmission differently in the hippocampus of each sex.

Autocrine interferon-γ may affect malignant behavior and sensitivity to tamoxifen of MCF-7 via estrogen receptor β subtype.

Mitogenic actions of estrogens are mediated by two distinct estrogen receptors (ERs), which are critical in the progression and therapeutic response of breast cancer. ER expression is a dynamic phenomenon that is regulated by numerous factors, including cytokines, in the tumor microenvironment. Recently, studies have shown that autocrine production of IL-4 promotes cancer cell growth and there is negative correlation between tumor IL-4 and hormone receptor levels, suggesting that there is crosstalk between cytokine receptors and ER. Thus, we evaluated for interaction between the two ERs and the cytokines IL-4 and IFN-γ, and if this interaction modulates malignant behavior. We identified that ERβ exerts protective activity in the progression of breast cancer cell line MCF-7, which co-expresses ERα and ERβ. IFN-γ and IL-4 have the opposite effects on malignant biological behavior. Furthermore, we found positive correlation between IFN-γ and ERβ expression in MCF-7. We also determined that autocrine IFN-γ in MCF-7 increases mRNA expression of ERβ resulting in enhanced sensitivity to tamoxifen (TAM). These results indicate that ERβ and autocrine IFN-γ represent two putative targets for breast cancer therapy.

Reporter cell lines to evaluate the selectivity of chemicals for human and zebrafish estrogen and peroxysome proliferator activated γ receptors.

Zebrafish is increasingly used as an animal model to study the effects of environmental nuclear receptors (NRs) ligands. As most of these compounds have only been tested on human NRs, it is necessary to measure their effects on zebrafish NRs. Estrogen receptors (ER) α and β and peroxysome proliferator activated receptor (PPAR) γ are main targets of environmental disrupting compounds (EDCs). In humans there are two distinct nuclear ERs (hERα and hERβ), whereas the zebrafish genome encodes three ERs, zfERα, zfERβ1, and zfERβ2. Only one isoform of PPARγ is expressed in both humans and zebrafish. In this review, we described reporter cell lines that we established to study the interaction of EDCs with human and zebrafish ERs and PPARγ. Using these cell lines, we observed that zfERs are thermo-sensitive while zfPPARγ is not. We also showed significant differences in the ability of environmental and synthetic ligands to modulate activation of zfERs and zfPPARγ in comparison to hERs and hPPARγ. Some environmental estrogens (bisphenol A, mycoestrogens) which are hER panagonists displayed greater potency for zfERα as compared to zfERβs. hERβ selective agonists (8βVE2, DPN, phytoestrogens) also displayed zfERα selectivity. Among hERα selective synthetic agonists, 16α-LE2 was the most zfERα selective compound. Almost all zfPPARγ environmental ligands (halogenated bisphenol A derivatives, phthalates, perfluorinated compounds) displayed similar affinity for human and zebrafish PPARγ while pharmaceutical hPPARγ agonists like thiazolidones are not recognized by zfPPARγ. Altogether, our studies show that all hERs and hPPARγ ligands do not control in a similar manner the transcriptional activity of zfERs and zfPPARγ and point out that care has to be taken in transposing the results obtained using the zebrafish as a model for human physiopathology.

ERβ and ERα Differentially Regulate NKT and Vγ4+ T-cell Activation and T-regulatory Cell Response in Coxsackievirus B3 Infected Mice.

Coxsackievirus B3 (CVB3) induced myocarditis is sex dependent with males developing more severe disease than females. Previous studies had shown that sex-associated hormones determine the sex bias with testosterone and progesterone promoting myocarditis while estrogen (E2) is protective. There are two major estrogen receptors: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). The goal of the current study was to determine the relative role of these receptors to myocarditis susceptibility and the mechanism of their action. Female C57Bl/6 wild-type mice and C57Bl/6 mice deficient in ERα, or ERβ were infected intraperitoneally with 102 plaque forming units CVB3. After 7 days, hearts were evaluated for virus titers by plaque forming assay and myocardial inflammation. Lymphoid cells either from the spleen or infiltrating the heart were characterized by labeling with antibodies including CD4, CD25, FoxP3, IFNγ, IL-4, CD11b, CD1d, Vγ4, TCRβ, or with CD1d-tetramer and evaluated by flow cytometry. To confirm that signaling through distinct estrogen receptors controlled myocarditis susceptibility and T-regulatory cell response, male C57Bl/6 mice were treated with the ERα-specific agonist, propyl pyrazole triol (PPT), ERβ agonist, diarylpropionitrile (DPN), or 17-β-estradiol (E2) as a non-specific estrogen receptor agonist. Myocarditis, cardiac virus titers, and CD4+ Th1 (IFNγ) bias were increased in infected ERαKO and decreased in infected ERβKO mice compared to C57Bl/6 controls. CD4+Th1 bias and myocarditis severity correlated inversely with numbers of CD4+CD25+FoxP3+ T regulatory cells which were decreased in ERαKO and increased in ERβKO mice. Increased T-regulatory cells corresponded to a preferential activation of natural killer T (NKT) cells in ERβKO mice. Male C57Bl/6 mice treated with DPN showed increased myocarditis while those treated with PPT and E2 showed decreased myocarditis corresponding to either decreased (DPN) or increased (PPT/E2) T-regulatory cell responses in male C57Bl/6 mice. DPN and PPT treatment had no effect on T-regulatory cell responses in NKT KO or γδKO mice. These results demonstrate that ERα and ERβ both modulated CVB3 myocarditis susceptibility but in opposite directions and that their predominant effect is mediated through their ability to alter NKT and Vγ4+ innate T cell responses in the infected host. It is these innate T cells which positively or negatively modulate T-regulatory cell responses.

Update on the neuroprotective effect of estrogen receptor alpha against Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by memory loss and disordered cognition. Women have a higher AD incidence than men, indicating that the declining estrogen levels during menopause may influence AD pathogenesis. However, the mechanism underlying estrogen's neuroprotective effect is not fully clarified and is complicated by the presence of several distinct estrogen receptor (ER) types and the identification of a growing number of ER splice variants. Thus, a deeper analysis of ERs could elucidate the role of estrogen in age-related cognitive changes. Intracellular calcium signaling cascades play a pivotal role in ERα neuroprotection against AD. The ERα-mediated inhibition of Death domain-associated protein (Daxx) translocation and the combination of membrane ERα and caveolin in caveolae may protect against AD. Moreover, the voltage-dependent anion channel (VDAC)/ERα association may be important for maintaining channel inactivation and may be relevant in neuronal preservation against Aβ injury. Additionally, ERα may prevent glutamate excitotoxic injury by Aβ through estrogen signaling mechanisms. ERα and IGF-IR co-activation may mediate neuroprotection, and many other growth factors and intracellular signaling responses triggered by ERα may also play important roles in this process. Furthermore, details regarding the genes and mRNA variants of ERα that are expressed in different parts of the human organs have been clarified recently. Therefore, here we review the literature to clarify the neuroprotective role of ERα. This review focuses on the potential mechanisms mediated by ERα in the intracellular signaling events in nervous system cells, thereby clarifying ERα-mediated protection against AD.

Estrogen receptors’ neuroprotective effect against glutamate-induced neurotoxicity

Glutamate is the most abundant excitatory brain neurotransmitter that has important functional significance with respect to neurodegenerative conditions. Glutamate-mediated excitotoxicity and neurodegeneration in Alzheimer's disease (AD) has been gradually becoming elucidated recently. Excessive release of glutamate induces an increase in intracellular Ca(2+) levels, thus triggers a cascade of cellular responses, ultimately leading to neuronal cell death. This type of neuronal damage induced by over-excitation has been proposed to be involved in a number of neuropathological conditions, ranging from acute insults to chronic neurodegenerative disorders. Estrogen could be effective in modulating glutamate-induced neurotoxicity and the protective responsivenesses are mostly estrogen receptors (ERs)-dependent. However, the mechanism underlying estrogen's neuroprotective effect is not fully clarified and is complicated by the presence of several distinct ER types. So a deeper research into the neuroprotection of ERs might be informative about the positive effect that estrogen might have on ageing-related cognitive changes. Extensive studies have indicated the neuroprotective effects of ERs against glutamate-induced neurotoxicity. The purpose of this review is to elucidate ERs' neuroprotective effects against glutamate-induced cytotoxicity and explore new ways to prevent and cure neurotoxicity-associated neurodegenerative disorders.

Novel daidzein analogs enhance osteogenic activity of bone marrow-derived mesenchymal stem cells and adipose-derived stromal/stem cells through estrogen receptor dependent and independent mechanisms.

IntroductionOsteoporosis is a disease characterized by low bone mineral density (BMD) and increased risk of fractures. Studies have demonstrated the use of phytoestrogens, or plant-derived estrogens, such as genistein and daidzein, to effectively increase osteogenic activity of bone marrow-derived mesenchymal stem cells (BMSCs). Herein, the effects of daidzein analogs on the osteogenic differentiation efficiency of human BMSC and adipose-derived stromal/stem cells (ASC) were explored.MethodsBMSCs and ASCs underwent osteogenic differentiation in the presence of vehicle, 17β-estradiol (E2), phytoestrogens, or daidzein analogs. Cells were stained for alkaline phosphatase (ALP) enzymatic activity, calcium deposition by alizarin red s, and phosphate mineralization by silver nitrate. Gene expression analysis was conducted on cells treated with daidzein analogs.ResultsCells treated with E2, daidzein, or genistein increased calcium deposition by 1.6-, 1.5-, and 1.4-fold, respectively, relative to vehicle-treated BMSCs and 1.6-, 1.7-, and 1.4-fold relative to vehicle-treated ASCs, respectively. BMSCs treated with daidzein analog 2c, 2g, and 2l demonstrated a 1.6-, 1.6-, and 1.9-fold increase in calcium deposition relative to vehicle-treated BMSCs, respectively, while ASCs treated with daidzein analog 2c, 2g, or 2l demonstrated a 1.7-, 2.0-, and 2.2-fold increase in calcium deposition relative to vehicle-treated ASCs, respectively. Additional analysis with BMSCs and ASCs was conducted in the more efficient compounds: 2g and 2l. ALP activity and phosphate mineralization was increased in 2g- and 2l-treated cells. The analysis of lineage specific gene expression demonstrated increased expression of key osteogenic genes (RUNX2, c-FOS, SPARC, DLX5, SPP1, COL1A1, IGF1, SOST, and DMP1) and earlier induction of these lineage specific genes, following treatment with 2g or 2l, relative to vehicle-treated cells. Estrogen receptor (ER) inhibitor studies demonstrated that ER antagonist fulvestrant inhibited the osteogenic differentiation of 2g in BMSCs and ASCs, while fulvestrant only attenuated the effects of 2l, suggesting that 2l acts by both ER dependent and independent pathways.ConclusionsThese studies provide support for exploring the therapeutic efficacy of daidzein derivatives for the treatment of osteoporosis. Furthermore, the patterns of gene induction differed following treatment with each daidzein analog, suggesting that these daidzein analogs activate distinct ER and non-ER pathways to induce differentiation in BMSCs and ASCs.Electronic supplementary materialThe online version of this article (doi:10.1186/scrt493) contains supplementary material, which is available to authorized users.