Role of estrogen receptor beta in neural differentiation of mouse embryonic stem cells

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

Molecular insights into the potential effects of selective estrogen receptor β agonists in Alzheimer's and Parkinson's diseases

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative disorders. Pathologically, AD and PD are characterized by the accumulation of misfolded proteins. Hence, they are also called as proteinopathy diseases. Gender is considered as one of the risk factors in both diseases. Estrogens are widely accepted to be neuroprotective in several neurodegenerative disorders. Estrogens can be produced in the central nervous system, where they are called as neurosteroids. Estrogens mediate their neuroprotective action mainly through their actions on estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). However, ERα is mainly involved in the growth and development of the primary and secondary sexual organs in females. Hence, the activation of ERα is associated with undesired side effects such as gynecomastia and increase in the risk of breast cancer, thromboembolism, and feminization. Therefore, selective activation of ERβ is often considered to be safer. In this review, we explore the role of ERβ in regulating the expression and functions of AD- and PD-associated genes. Additionally, we discuss the association of these genes with the amyloid-beta peptide (Aβ) and α-synuclein mediated toxicity. Ultimately, we established a correlation between the importance of ERβ activation and the process underlying ERβ's neuroprotective mechanisms in AD and PD.

Zebrafish as an emerging model to study estrogen receptors in neural development

Estrogens induce several regulatory signals in the nervous system that are mainly mediated through estrogen receptors (ERs). ERs are largely expressed in the nervous system, yet the importance of ERs to neural development has only been elucidated over the last decades. Accumulating evidence shows a fundamental role for estrogens in the development of the central and peripheral nervous systems, hence, the contribution of ERs to neural function is now a growing area of research. The conservation of the structure of the ERs and their response to estrogens make the zebrafish an interesting model to dissect the role of estrogens in the nervous system. In this review, we highlight major findings of ER signaling in embryonic zebrafish neural development and compare the similarities and differences to research in rodents. We also discuss how the recent generation of zebrafish ER mutants, coupled with the availability of several transgenic reporter lines, its amenability to pharmacological studies and in vivo live imaging, could help us explore ER function in embryonic neural development.

Estradiol and progesterone in female reward-learning, addiction, and therapeutic interventions

Sex steroid hormones like estradiol (E2) and progesterone (P4) guide the sexual organization and activation of the developing brain and control female reproductive behavior throughout the lifecycle; importantly, these hormones modulate functional activity of not just the endocrine system, but most of the nervous system including the brain reward system. The effects of E2 and P4 can be seen in the processing of and memory for rewarding stimuli and in the development of compulsive reward-seeking behaviors like those seen in substance use disorders. Women are at increased risk of developing substance use disorders; however, the origins of this sex difference are not well understood and therapeutic interventions targeting ovarian hormones have produced conflicting results. This article reviews the contribution of the E2 and P4 in females to functional modulation of the brain reward system, their possible roles in origins of addiction vulnerability, and the development and treatment of compulsive reward-seeking behaviors.

Embryonic Exposure to Cigarette Smoke Extract Impedes Skeletal Development and Evokes Craniofacial Defects in Zebrafish

Exposure to cigarette smoke represents the largest source of preventable death and disease in the United States. This may be in part due to the nature of the delayed harmful effects as well as the lack of awareness of the scope of harm presented by these products. The presence of “light” versions further clouds the harmful effects of tobacco products. While active smoking in expectant mothers may be reduced by educational and outreach campaigns, exposure to secondhand smoke is often involuntary yet may harm the developing embryo. In this study, we show that the main component of secondhand smoke, sidestream cigarette smoke, from several brands, including harm-reduction versions, triggered unsuccessful hatching at 3 dpf and reduced overall survival at 6 dpf in developing zebrafish. At non-lethal concentrations, craniofacial defects with different severity based on the cigarette smoke extract were noted by 6 dpf. All tested products, including harm-reduction products, significantly impacted cartilage formation and/or bone mineralization in zebrafish embryos, independent of whether the bones/cartilage formed from the mesoderm or neural crest. Together, these results in a model system often used to detect embryonic malformations imply that exposure of a woman to secondhand smoke while pregnant may lead to mineralization issues in the skeleton of her newborn, ultimately adding a direct in utero association to the increased fracture risk observed in children of mothers exposed to cigarette smoke.

Association Between Polymorphisms in Estrogen Receptor Genes and Depression in Women: A Meta-Analysis

Objective: It is suggested that estrogen receptors (ERs) might be associated with the disproportionate vulnerability of women to depressive episodes. Several variants in ER-alpha (ERα) and ER-beta (ERβ) have been linked to depression, but the results were not consistent. Hence, we conducted a meta-analysis to evaluate the association between ERα/ERβ and depression in a cohort of women.

Methods: A comprehensive literature search was performed in public databases. The genetic association between polymorphisms in Erα/ERβ and depression risk in a cohort of women was evaluated by odds ratios (ORs) and 95% confidence intervals (CIs). Cochran’s Q test and the I² index were used to evaluate heterogeneity.

Results: In total, 10 studies and 4 SNPs (rs2234693, rs9340799, rs4986938, rs1256049) were included in our meta-analysis. rs2234693 genotype was significantly associated with the risk of depression in women by dominant model (CC + CT vs TT, OR = 1.30, 95% CI: 1.09–1.55, p = 0.0031), recessive model (CC vs CT + TT, OR = 1.64, 95% CI: 1.00–2.67, p = 0.0478), additive model (CC vs TT, OR = 1.93, 95% CI: 1.12–3.35, p = 0.0189) and allelic model (C vs T, OR = 1.24, 95% CI: 1.10–1.39, p = 0.0003). For rs9340799, the frequencies of risk genotypes according to the dominant (GG + GA vs AA, OR = 1.47, 95% CI = 1.10–1.98, p = 0.0096, I² = 0%, p = 0.43) and allelic (G vs A, OR = 1.33, 95% CI: 1.04–1.69, p = 0.0236, I² = 0%, p = 0.39) models were significantly lower in women with depression than in controls within the Asian subgroup. For rs1256049, risk genotypes were significantly more frequent in depressed subjects than in controls under the dominant model (AA+ GA vs GG, OR = 1.62, 95% CI: 1.19–2.21, p = 0.0024) and the allelic model (A vs G, OR = 1.35, 95% CI: 1.07–1.72, p = 0.012) after sensitivity analysis by omitting one study which induce the heterogeneity.

Conclusions: The current meta-analysis is the first and most comprehensive investigation of the association between ERs and depression in women, and the findings support the concept that ERs participate in the etiology of sex heterogeneity in depression.

Perfluorinated Iodine Alkanes Promoted Neural Differentiation of mESCs by Targeting miRNA-34a-5p in Notch-Hes Signaling

The neurodevelopmental process is highly vulnerable to environmental stress from exposure to endocrine-disrupting chemicals. Perfluorinated iodine alkanes (PFIs) possess estrogenic activities, while their potential neurodevelopmental toxicity remains blurry. In the present study, the effects of two PFIs, including dodecafluoro-1,6-diiodohexane (PFHxDI) and tridecafluorohexyl iodide (PFHxI), were investigated in the neural differentiation of the mouse embryonic stem cells (mESCs). Without influencing the cytobiological process of the mESCs, PFIs interfered the triploblastic development by increasing ectodermal differentiation, thus promoting subsequent neurogenesis. The temporal regulation of PFIs in Notch-Hes signaling through the targeting of mmu-miRNA-34a-5p provided a substantial explanation for the underlying mechanism of PFI-promoted mESC commitment to the neural lineage. The findings herein provided new knowledge on the potential neurodevelopmental toxicities of PFIs, which would help advance the health risk assessment of these kinds of emerging chemicals.

Loss of Foxd4 Impacts Neurulation and Cranial Neural Crest Specification During Early Head Development

The specification of anterior head tissue in the late gastrulation mouse embryo relies on signaling cues from the visceral endoderm and anterior mesendoderm (AME). Genetic loss-of-function studies have pinpointed a critical requirement of LIM homeobox 1 (LHX1) transcription factor in these tissues for the formation of the embryonic head. Transcriptome analysis of embryos with gain-of-function LHX1 activity identified the forkhead box gene, Foxd4, as one downstream target of LHX1 in late-gastrulation E7.75 embryos. Our analysis of single-cell RNA-seq data show Foxd4 is co-expressed with Lhx1 and Foxa2 in the anterior midline tissue of E7.75 mouse embryos, and in the anterior neuroectoderm (ANE) at E8.25 alongside head organizer genes Otx2 and Hesx1. To study the role of Foxd4 during early development we used CRISPR-Cas9 gene editing in mouse embryonic stem cells (mESCs) to generate bi-allelic frameshift mutations in the coding sequence of Foxd4. In an in vitro model of the anterior neural tissues derived from Foxd4-loss of function (LOF) mESCs and extraembryonic endoderm cells, expression of head organizer genes as well as Zic1 and Zic2 was reduced, pointing to a need for FOXD4 in regulating early neuroectoderm development. Mid-gestation mouse chimeras harbouring Foxd4-LOF mESCs displayed craniofacial malformations and neural tube closure defects. Furthermore, our in vitro data showed a loss of FOXD4 impacts the expression of cranial neural crest markers Twist1 and Sox9. Our findings have demonstrated that FOXD4 is essential in the AME and later in the ANE for rostral neural tube closure and neural crest specification during head development.

Application of Transgenic Zebrafish Models for Studying the Effects of Estrogenic Endocrine Disrupting Chemicals on Embryonic Brain Development

Endocrine disrupting chemicals (EDCs) are environmental pollutants that mimic hormones and/or disrupt their function. Estrogenic EDCs (eEDCs) interfere with endogenous estrogen signalling pathway(s) and laboratory animal and human epidemiological studies have provided evidence for a causal link between exposure to them during embryonic/early life and neurological impairments. However, our understanding of the molecular and cellular mechanism(s) underlying eEDCs exposure effects on brain development, tissue architecture and function and behaviour are limited. Transgenic (TG) zebrafish models offer new approach methodologies (NAMs) to help identify the modes of action (MoAs) of EDCs and their associated impacts on tissue development and function. Estrogen biosensor TG zebrafish models have been applied to study eEDC interactions and resulting transcriptional activation (via a fluorescent reporter expression) across the entire body of the developing zebrafish embryo, including in real time. These estrogen biosensor TG zebrafish models are starting to deepen our understanding of the spatiotemporal actions of eEDCs and their resulting impacts on neurological development, brain function and behaviour. In this review, we first investigate the links between early life exposure to eEDCs and neurodevelopmental alterations in model organisms (rodents and zebrafish) and humans. We then present examples of the application of estrogen biosensor and other TG zebrafish models for elucidating the mechanism(s) underlying neurodevelopmental toxicities of eEDCs. In particular we illustrate the utility of combining estrogen biosensor zebrafish models with other TG zebrafish models for understanding the effects of eEDCs on the brain, spanning cellular processes, brain circuitry, neurophysiology and behaviour. Finally, we discuss the future prospects of TG zebrafish models as experimental models for studying more complex scenarios for exposure to contaminant mixtures on neurological development and function.

Estrogens regulate early embryonic development of the olfactory sensory system via estrogen-responsive glia

Estrogens are well-known to regulate development of sexual dimorphism of the brain; however, their role in embryonic brain development prior to sex-differentiation is unclear. Using estrogen biosensor zebrafish models, we found that estrogen activity in the embryonic brain occurs from early neurogenesis specifically in a type of glia in the olfactory bulb (OB), which we name estrogen-responsive olfactory bulb (EROB) cells. In response to estrogen, EROB cells overlay the outermost layer of the OB and interact tightly with olfactory sensory neurons at the olfactory glomeruli. Inhibiting estrogen activity using an estrogen receptor antagonist, ICI182,780 (ICI), and/or EROB cell ablation impedes olfactory glomerular development, including the topological organisation of olfactory glomeruli and inhibitory synaptogenesis in the OB. Furthermore, activation of estrogen signalling inhibits both intrinsic and olfaction-dependent neuronal activity in the OB, whereas ICI or EROB cell ablation results in the opposite effect on neuronal excitability. Altering the estrogen signalling disrupts olfaction-mediated behaviour in later larval stage. We propose that estrogens act on glia to regulate development of OB circuits, thereby modulating the local excitability in the OB and olfaction-mediated behaviour.

Estrogen receptors and the aging brain

The female sex hormone estrogen has been ascribed potent neuroprotective properties. It signals by binding and activating estrogen receptors that, depending on receptor subtype and upstream or downstream effectors, can mediate gene transcription and rapid non-genomic actions. In this way, estrogen receptors in the brain participate in modulating neural differentiation, proliferation, neuroinflammation, cholesterol metabolism, synaptic plasticity, and behavior. Circulating sex hormones decrease in the course of aging, more rapidly at menopause in women, and slower in men. This review will discuss what this drop entails in terms of modulating neuroprotection and resilience in the aging brain downstream of spatiotemporal estrogen receptor alpha (ERα) and beta (ERβ) signaling, as well as in terms of the sex differences observed in Alzheimer's disease (AD) and Parkinson's disease (PD). In addition, controversies related to ER expression in the brain will be discussed. Understanding the spatiotemporal signaling of sex hormones in the brain can lead to more personalized prevention strategies or therapies combating neurodegenerative diseases.

Prenatal Octamethylcyclotetrasiloxane Exposure Impaired Proliferation of Neuronal Progenitor, Leading to Motor, Cognition, Social and Behavioral Functions

Cyclic siloxane octamethylcyclotetrasiloxane (D4) has raised concerns as an endocrine-disrupting chemical (EDC). D4 is widely used in detergent products, cosmetics, and personal care products. Recently, robust toxicological data for D4 has been reported, but the adverse effects of D4 on brain development are unknown. Here, pregnant mice on gestational day 9.5 were treated daily with D4 to postnatal day 28, and the offspring mice were studied. The prenatal D4-treated mice exhibited cognitive dysfunction, limited memory, and motor learning defect. Moreover, prenatal D4 exposure reduced the proliferation of neuronal progenitors in the offspring mouse brain. Next, the mechanisms through which D4 regulated the cell cycle were investigated. Aberrant gene expression, such as cyclin-dependent kinases CDK6 and cyclin-dependent kinase inhibitor p27, were found in the prenatal D4-treated mice. Furthermore, the estrogen receptors ERa and ERb were increased in the brain of prenatal D4-treated mice. Overall, these findings suggest that D4 exerts estrogen activity that affects the cell cycle progression of neuronal progenitor cells during neurodevelopment, which may be associated with cognitive deficits in offspring.

Obesity alters the ovarian proteomic response to zearalenone exposure†

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin, is detrimental to female reproduction. Altered chemical biotransformation, depleted primordial follicles and a blunted genotoxicant response have been discovered in obese female ovaries, thus, this study investigated the hypothesis that obesity would enhance ovarian sensitivity to ZEN exposure. Seven-week-old female wild-type nonagouti KK.Cg-a/a mice (lean) and agouti lethal yellow KK.Cg-Ay/J mice (obese) received food and water ad libitum, and either saline or ZEN (40 μg/kg) per os for 15 days. Body and organ weights, and estrous cyclicity were recorded, and ovaries collected posteuthanasia for protein analysis. Body and liver weights were increased (P < 0.05) in the obese mice, but obesity did not affect (P > 0.05) heart, kidney, spleen, uterus, or ovary weight and there was no impact (P > 0.05) of ZEN exposure on body or organ weight in lean or obese mice. Obese mice had shorter proestrus (P < 0.05) and a tendency (P = 0.055) for longer metestrus/diestrus. ZEN exposure in obese mice increased estrus but shortened metestrus/diestrus length. Neither obesity nor ZEN exposure impacted (P > 0.05) circulating progesterone, or ovarian abundance of EPHX1, GSTP1, CYP2E1, ATM, BRCA1, DNMT1, HDAC1, H4K16ac, or H3K9me3. Lean mice exposed to ZEN had a minor increase in γH2AX abundance (P < 0.05). In lean and obese mice, LC–MS/MS identified alterations to proteins involved in chemical metabolism, DNA repair and reproduction. These data identify ZEN-induced adverse ovarian modes of action and suggest that obesity is additive to ZEN-induced ovotoxicity.

Comparative Neurodevelopment Effects of Bisphenol A and Bisphenol F on Rat Fetal Neural Stem Cell Models

Bisphenol A (BPA) is considered as one of the most extensively synthesized and used chemicals for industrial and consumer products. Previous investigations have established that exposure to BPA has been linked to developmental, reproductive, cardiovascular, immune, and metabolic effects. Several jurisdictions have imposed restrictions and/or have banned the use of BPA in packaging material and other consumer goods. Hence, manufacturers have replaced BPA with its analogues that have a similar chemical structure. Some of these analogues have shown similar endocrine effects as BPA, while others have not been assessed. In this investigation, we compared the neurodevelopmental effects of BPA and its major replacement Bisphenol F (BPF) on rat fetal neural stem cells (rNSCs). rNSCs were exposed to cell-specific differentiation media with non-cytotoxic doses of BPA or BPF at the range of 0.05 M to 100 M concentrations and measured the degree of cell proliferation, differentiation, and morphometric parameters. Both of these compounds increased cell proliferation and impacted the differentiation rates of oligodendrocytes and neurons, in a concentration-dependent manner. Further, there were concentration-dependent decreases in the maturation of oligodendrocytes and neurons, with a concomitant increase in immature oligodendrocytes and neurons. In contrast, neither BPA nor BPF had any overall effect on cellular proliferation or the cytotoxicity of astrocytes. However, there was a concentration-dependent increase in astrocyte differentiation and morphological changes. Morphometric analysis for the astrocytes, oligodendrocytes, and neurons showed a reduction in the arborization. These data show that fetal rNSCs exposed to either BPA or BPF lead to comparable changes in the cellular differentiation, proliferation, and arborization processes.

Estrogen receptor beta and neural development

The female sex hormone estradiol (E2, 17β-estradiol) has important functions in the developing brain. In addition to regulating sexual differentiation of the brain, E2 participates in the development of brain areas involved in functions unrelated to reproduction, such as cognition. E2 signals mainly thorough two estrogen receptors; estrogen receptor alpha (ERα) and beta (ERβ). While ERα has distinct functions for sexual imprinting of the developing brain, ERβ is considered to participate in the development of brain areas related to cognitive function. In this chapter we will focus on ERβ's role during neural development. We will discuss the contributions of sex chromosomal and sex hormonal effects in this process and place it in relation to recent data on ERβ obtained from stem cell models. Finally, we will discuss the lessons learned from mouse and stem cell models in understanding ERβ's role in neural development and how new stem cell models, by addressing the human relevance, may help to advance our progress in this field.

Hormonal Regulation of Oligodendrogenesis I: Effects across the Lifespan

The brain’s capacity to respond to changing environments via hormonal signaling is critical to fine-tuned function. An emerging body of literature highlights a role for myelin plasticity as a prominent type of experience-dependent plasticity in the adult brain. Myelin plasticity is driven by oligodendrocytes (OLs) and their precursor cells (OPCs). OPC differentiation regulates the trajectory of myelin production throughout development, and importantly, OPCs maintain the ability to proliferate and generate new OLs throughout adulthood. The process of oligodendrogenesis, the creation of new OLs, can be dramatically influenced during early development and in adulthood by internal and environmental conditions such as hormones. Here, we review the current literature describing hormonal regulation of oligodendrogenesis within physiological conditions, focusing on several classes of hormones: steroid, peptide, and thyroid hormones. We discuss hormonal regulation at each stage of oligodendrogenesis and describe mechanisms of action, where known. Overall, the majority of hormones enhance oligodendrogenesis, increasing OPC differentiation and inducing maturation and myelin production in OLs. The mechanisms underlying these processes vary for each hormone but may ultimately converge upon common signaling pathways, mediated by specific receptors expressed across the OL lineage. However, not all of the mechanisms have been fully elucidated, and here, we note the remaining gaps in the literature, including the complex interactions between hormonal systems and with the immune system. In the companion manuscript in this issue, we discuss the implications of hormonal regulation of oligodendrogenesis for neurological and psychiatric disorders characterized by white matter loss. Ultimately, a better understanding of the fundamental mechanisms of hormonal regulation of oligodendrogenesis across the entire lifespan, especially in vivo, will progress both basic and translational research.

TWIST1 and chromatin regulatory proteins interact to guide neural crest cell differentiation

Protein interaction is critical molecular regulatory activity underlining cellular functions and precise cell fate choices. Using TWIST1 BioID-proximity-labeling and network propagation analyses, we discovered and characterized a TWIST-chromatin regulatory module (TWIST1-CRM) in the neural crest cells (NCC). Combinatorial perturbation of core members of TWIST1-CRM: TWIST1, CHD7, CHD8, and WHSC1 in cell models and mouse embryos revealed that loss of the function of the regulatory module resulted in abnormal differentiation of NCCs and compromised craniofacial tissue patterning. Following NCC delamination, low level of TWIST1-CRM activity is instrumental to stabilize the early NCC signatures and migratory potential by repressing the neural stem cell programs. High level of TWIST1 module activity at later phases commits the cells to the ectomesenchyme. Our study further revealed the functional interdependency of TWIST1 and potential neurocristopathy factors in NCC development.

Shaping the head and face during development relies on a complex ballet of molecular signals that orchestrates the movement and specialization of various groups of cells. In animals with a backbone for example, neural crest cells (NCCs for short) can march long distances from the developing spine to become some of the tissues that form the skull and cartilage but also the pigment cells and nervous system.

NCCs mature into specific cell types thanks to a complex array of factors which trigger a precise sequence of binary fate decisions at the right time and place. Amongst these factors, the protein TWIST1 can set up a cascade of genetic events that control how NCCs will ultimately form tissues in the head. To do so, the TWIST1 protein interacts with many other molecular actors, many of which are still unknown.

To find some of these partners, Fan et al. studied TWIST1 in the NCCs of mice and cells grown in the lab. The experiments showed that TWIST1 interacted with CHD7, CHD8 and WHSC1, three proteins that help to switch genes on and off, and which contribute to NCCs moving across the head during development. Further work by Fan et al. then revealed that together, these molecular actors are critical for NCCs to form cells that will form facial bones and cartilage, as opposed to becoming neurons. This result helps to show that there is a trade-off between NCCs forming the face or being part of the nervous system.

One in three babies born with a birth defect shows anomalies of the head and face: understanding the exact mechanisms by which NCCs contribute to these structures may help to better predict risks for parents, or to develop new approaches for treatment.

Activation of estrogen receptor beta signaling reduces stemness of glioma stem cells

Glioblastoma (GBM) is the most common and deadliest tumor of the central nervous system. GBM has poor prognosis and glioma stem cells (GSCs) are implicated in tumor initiation and therapy resistance. Estrogen receptor β (ERβ) is expressed in GBM and exhibit tumor suppressive function. However, the role of ERβ in GSCs and the therapeutic potential of ERβ agonists on GSCs remain largely unknown. Here, we examined whether ERβ modulates GSCs stemness and tested the utility of two ERβ selective agonists (LY500307 and Liquiritigenin) to reduce the stemness of GSCs. The efficacy of ERβ agonists was examined on GSCs isolated from established and patient derived GBMs. Our results suggested that knockout of ERβ increased the proportion of CD133+ and SSEA+ positive GSCs and overexpression of ERβ reduced the proportion of GSCs in GBM cells. Overexpression of ERβ or treatment with ERβ agonists significantly inhibited the GSCs cell viability, neurosphere formation, self-renewal ability, induced the apoptosis and reduced expression of stemness markers in GSCs. RNA sequencing analysis revealed that ERβ agonist modulate pathways related to stemness, differentiation and apoptosis. Mechanistic studies showed that ERβ overexpression or agonist treatment reduced glutamate receptor signaling pathway and induced apoptotic pathways. In orthotopic models, ERβ overexpression or ERβ agonists treatment significantly reduced the GSCs mediated tumor growth and improved the mice overall survival. Immunohistochemical studies demonstrated that ERβ overexpression decreased SOX2 and GRM3 expression and increased expression of GFAP in tumors. These results suggest that ERβ activation could be a promising therapeutic strategy to eradicate GSCs.

Estrogen and estrogen receptors in kidney diseases

Acute kidney injury (AKI) and chronic kidney disease (CKD) are posing great threats to global health within this century. Studies have suggested that estrogen and estrogen receptors (ERs) play important roles in many physiological processes in the kidney. For instance, they are crucial in maintaining mitochondrial homeostasis and modulating endothelin-1 (ET-1) system in the kidney. Estrogen takes part in the kidney repair and regeneration via its receptors. Estrogen also participates in the regulation of phosphorus homeostasis via its receptors in the proximal tubule. The ERα polymorphisms have been associated with the susceptibilities and outcomes of several renal diseases. As a consequence, the altered or dysregulated estrogen/ERs signaling pathways may contribute to a variety of kidney diseases, including various causes-induced AKI, diabetic kidney disease (DKD), lupus nephritis (LN), IgA nephropathy (IgAN), CKD complications, etc. Experimental and clinical studies have shown that targeting estrogen/ERs signaling pathways might have protective effects against certain renal disorders. However, many unsolved problems still exist in knowledge regarding the roles of estrogen and ERs in distinct kidney diseases. Further research is needed to shed light on this area and to enable the discovery of pathway-specific therapies for kidney diseases.

Motor Function Deficits in the Estrogen Receptor Beta Knockout Mouse: Role on Excitatory Neurotransmission and Myelination in the Motor Cortex

BACKGROUND

Male estrogen receptor beta (ERβ) knockout (BERKO) mice display anxiety and aggression linked to, among others, altered serotonergic signaling in the basolateral amygdala and dorsal raphe, impaired cortical radial glia migration, and reduced GABAergic signaling. The effects on primary motor cortex (M1 cortex) and locomotor activity as a consequence of ERβ loss have not been investigated.

OBJECTIVE

The aim of this study was to determine whether locomotor activity is altered as a consequence of the changes in the M1 cortex.

METHODS

The locomotor activity of male wild-type (WT) and BERKO mice was evaluated using the open-field and rotarod tests. Molecular changes in the M1 cortex were analyzed by RNA sequencing, electron microscopy, electrophysiology, and immunohistological techniques. In addition, we established oligodendrocyte (OL) cultures from WT and BERKO mouse embryonic stem cells to evaluate OL function.

RESULTS

Locomotor profiling revealed that BERKO mice were more active than WT mice but had impaired motor coordination. Analysis of the M1 cortex pointed out differences in synapse function and myelination. There was a reduction in GABAergic signaling resulting in imbalanced excitatory and inhibitory neurotransmission as well as a defective OL differentiation accompanied by myelin defects. The effects of ERβ loss on OL differentiation were confirmed in vitro.

CONCLUSION

ERβ is an important regulator of GABAergic interneurons and OL differentiation, which impacts on adult M1 cortex function and may be linked to increased locomotor activity and decreased motor coordination in BERKO mice.

Androgen Receptor signaling promotes the neural progenitor cell pool in the developing cortex

Neural Progenitor Cells (NPCs) are multipotent cells that are able to self-renew and differentiate into neurons. The size of the initial pool of NPCs during the brain development strongly affects the number of neurons that compose cortical multi-layer during development. Gonadal hormones can influence the balance between self-renewal and differentiation processes. Herein, we investigated the role of dihydrotestosterone (DHT), the active metabolite of testosterone, in the regulation of NPC stemness and differentiation. First, we evaluated the expression of the androgen receptor (AR), the transcription factor activated by DHT that mediates the physiological effects of androgens, in NPCs. Western blot analysis showed that DHT-mediated activation of AR induces mitogenic signaling pathways (PI3K/AKT and MAPK/ERK) in NPCs, whereas luciferase activity assays demonstrated the induction of AR transcriptional activity. AR activation mediated by DHT treatment strongly increased the proliferation of NPCs and reduced their propensity to differentiate into neurons. Furthermore, the effects of AR activation were mediated, at least in part, by increased expression of Aldehyde Dehydrogenase 1 Family Member A3 enzyme (ALDH1A3). Pharmacological inhibition of ALDH activity with N,N-diethylaminobenzaldehyde (DEAB) reduced the effect of DHT on NPC proliferation in vitro. Furthermore, inhibition of AR activity by Enzalutamide reduced the NPC pool in the developing cortex of male C57/BL6 mouse embryos. These findings indicate that androgens engage an AR-dependent signaling pathway that impact on neurogenesis by increasing the NPC pool in the developing mouse cortex.

17β-Estradiol Protects Neural Stem/Progenitor Cells Against Ketamine-Induced Injury Through Estrogen Receptor β Pathway

Ketamine inhibits neural stem/progenitor cell (NSPC) proliferation and disrupts normal neurogenesis in the developing brain. 17β-Estradiol alleviates neurogenesis damage and enhances behavioral performance after ketamine administration. However, the receptor pathway of 17β-estradiol that protects NSPCs from ketamine-induced injury remains unknown. In the present study, we investigated the role of estrogen receptor α (ER-α) and estrogen receptor β (ER-β) in 17β-estradiol’s protection against ketamine-exposed NSPCs and explored its potential mechanism. The primary cultured NSPCs were identified by immunofluorescence and then treated with ketamine and varying doses of ER-α agonist 4,4′,4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT) or ER-β agonist 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN) for 24 h. NSPC proliferation was analyzed by 5-bromo-2-deoxyuridine incorporation test. The expression of phosphorylated glycogen synthase kinase-3β (p-GSK-3β) was quantified by western blotting. It was found that treatment with different concentrations of PPT did not alter the inhibition of ketamine on NSPC proliferation. However, treatment with DPN attenuated the inhibition of ketamine on NSPC proliferation at 24 h after their exposure (P < 0.05). Furthermore, treatment with DPN increased p-GSK-3β expression in NSPCs exposed to ketamine. These findings indicated that ER-β mediates probably the protective effects of 17β-estradiol on ketamine-damaged NSPC proliferation and GSK-3β is involved in this process

Hippo-YAP signaling controls lineage differentiation of mouse embryonic stem cells through modulating the formation of super-enhancers

Hippo-YAP signaling pathway functions in early lineage differentiation of pluripotent stem cells, but the detailed mechanisms remain elusive. We found that knockout (KO) of Mst1 and Mst2, two key components of the Hippo signaling in mouse embryonic stem cells (ESCs), resulted in a disruption of differentiation into mesendoderm lineage. To further uncover the underlying regulatory mechanisms, we performed a series of ChIP-seq experiments with antibodies against YAP, ESC master transcription factors and some characterized histone modification markers as well as RNA-seq assays using wild type and Mst KO samples at ES and day 4 embryoid body stage respectively. We demonstrate that YAP is preferentially co-localized with super-enhancer (SE) markers such as Nanog, Sox2, Oct4 and H3K27ac in ESCs. The hyper-activation of nuclear YAP in Mst KO ESCs facilitates the binding of Nanog, Sox2 and Oct4 as well as H3K27ac modification at the loci where YAP binds. Moreover, Mst depletion results in novel SE formation and enhanced liquid-liquid phase-separated Med1 condensates on lineage associated genes, leading to the upregulation of these genes and the distortion of ESC differentiation. Our study reveals a novel mechanism on how Hippo-YAP signaling pathway dictates ESC lineage differentiation.

Ventral prostate and mammary gland phenotype in mice with complete deletion of the ERβ gene

Disagreements about the phenotype of estrogen receptor β (ERβ) knockout mouse, created by removing the DNA-binding domain of the ERβ gene or interruption of the gene with a neocassette (Oliver Smithies ERβ knockout mice [ERβ^OS-/-]), prompted us to create an ERβ knockout mouse by deleting the ERβ gene with the use of CRISPR/Cas9 technology. We confirmed that the ERβ gene was eliminated from the mouse genome and that no ERβ mRNA or protein was detectable in tissues of this mouse. Overall the phenotype of the ventral prostate (VP) and mammary gland (MG) in ERβ^crispr-/- mice was similar to, but more severe than, that in the ERβ^OS-/-mice. In the VP of 6-mo-old ERβ^crispr-/- mice there was epithelial hyperplasia, fibroplasia, inflammation, stromal overgrowth, and intraductal cancer-like lesions. This was accompanied by an increase in Ki67 and P63 and loss in DACH1 and PURα, two androgen receptor (AR) repressors. In the MG there was overexpression of estrogen receptor α and progesterone receptor, loss of collagen, increase in proliferation and expression of metalloproteases, and invasive epithelium. Surprisingly, by 18 mo of age, the number of hyperplastic foci was reduced, the ducts of the VP and MG became atrophic, and, in the VP, there was massive immune infiltration and massive desquamation of the luminal epithelial cells. These changes were coincident with reduced levels of androgens in males and estrogens in females. We conclude that ERβ is a tumor suppressor gene in the VP and MG where its loss increases the activity AR and ERα, respectively.

Sexually dimorphic leanness and hypermobility in p16Ink4a/CDKN2A-deficient mice coincides with phenotypic changes in the cerebellum

p16Ink4a/CDKN2A is a tumor suppressor that critically regulates the cell cycle. Indeed, p16Ink4a deficiency promotes tumor formation in various tissues. We now report that p16Ink4a deficiency in female mice, but not male mice, induces leanness especially in old age, as indicated by lower body weight and smaller white adipose tissue, although other major organs are unaffected. Unexpectedly, the integrity, number, and sizes of adipocytes in white adipose tissue were unaffected, as was macrophage infiltration. Hence, hypermobility appeared to be accountable for the phenotype, since food consumption was not altered. Histological analysis of the cerebellum and deep cerebellar nuclei, a vital sensorimotor control center, revealed increased proliferation of neuronal cells and improved cerebellum integrity. Expression of estrogen receptor β (ERβ) and PCNA also increased in deep cerebellar nuclei, implying crosstalk between p16Ink4a and ERβ. Furthermore, p16Ink4a deficiency expands LC3B+ cells and GFAP+ astrocytes in response to estrogen. Collectively, the data suggest that loss of p16INK4a induces sexually dimorphic leanness in female mice, which appears to be due to protection against cerebellar senescence by promoting neuronal proliferation and homeostasis via ERβ.

Comparative Evaluation of Hormones and Hormone-Like Molecule in Lineage Specification of Human Induced Pluripotent Stem Cells

Background and Objectives

Proficient differentiation of human pluripotent stem cells (hPSCs) into specific lineages is required for applications in regenerative medicine. A growing amount of evidences had implicated hormones and hormone-like molecules as critical regulators of proliferation and lineage specification during in vivo development. Therefore, a deeper understanding of the hormones and hormone-like molecules involved in cell fate decisions is critical for efficient and controlled differentiation of hPSCs into specific lineages. Thus, we functionally and quantitatively compared the effects of diverse hormones (estradiol 17-β (E2), progesterone (P4), and dexamethasone (DM)) and a hormone-like molecule (retinoic acid (RA)) on the regulation of hematopoietic and neural lineage specification.

Methods and Results

We used 10 nM E2, 3 µM P4, 10 nM DM, and 10 nM RA based on their functional in vivo developmental potential. The sex hormone E2 enhanced functional activity of hematopoietic progenitors compared to P4 and DM, whereas RA impaired hematopoietic differentiation. In addition, E2 increased CD34⁺CD45⁺ cells with progenitor functions, even in the CD43^- population, a well-known hemogenic marker. RA exhibited lineage-biased potential, preferentially committing hPSCs toward the neural lineage while restricting the hematopoietic fate decision.

Conclusions

Our findings reveal unique cell fate potentials of E2 and RA treatment and provide valuable differentiation information that is essential for hPSC applications.

G protein-coupled estrogen receptor 1 negatively regulates the proliferation of mouse-derived neural stem/progenitor cells via extracellular signal-regulated kinase pathway

G protein-coupled estrogen receptor 1 (GPER1, also known as GPR30) has been reported to play a wide range of function in the central nervous system (CNS). However, whether GPER1 is expressed by neural stem/progenitor cells (NSPCs) and its role has not been established. Here, we found the expression of GPER1 in mouse-derived NSPCs via western blot and immunofluorescent staining. Moreover, we revealed that specific activation of GPER1 by the agonist G1 decreased the proliferation of NSPCs in a dose-dependent manner. The neurosphere formation assay and Ki67 staining further demonstrated that activation of GPER1 inhibited the proliferation of NSPCs. Additionally, the inhibitory effect of G1 on the proliferation of NSPCs could be blocked by the specific GPER1 antagonist G15. Intriguingly, ERK pathway was involved in the negative effect of GPER1 on the proliferation of NSPCs, because the phosphorylation level of ERK in NSPCs was remarkably decreased during G1 treatment. However, the antagonist G15 reversed the down-regulated level of p-ERK. Knock-down GPER1 also reversed the inhibitory effect of G1 on NSPCs proliferation. Together, our results provide the first evidence that GPER1 is expressed by NSPCs and its activation negatively modulates the proliferation of NSPCs, highlighting the importance of GPER1 in regulating NSPC behaviors.

Potentiation of paclitaxel effect by resveratrol in human breast cancer cells by counteracting the 17β-estradiol/estrogen receptor α/neuroglobin pathway

Neuroglobin (NGB), an antiapoptotic protein upregulated by 17β-estradiol (E2), is part of E2/estrogen receptor α (ERα) pathway pointed to preserve cancer cell survival in presence of microenvironmental stressors including chemotherapeutic drugs. Here, the possibility that resveratrol (Res), an anticancer plant polyphenol, could increase the susceptibility of breast cancer cells to paclitaxel (Pacl) by affecting E2/ERα/NGB pathway has been evaluated. In MCF-7 and T47D (ERα-positive), but not in MDA-MB 231 (ERα-negative) nor in SK-N-BE (ERα and ERβ positive), Res decreases NGB levels interfering with E2/ERα-induced NGB upregulation and with E2-induced ERα and protein kinase B phosphorylation. Although Res treatment does not reduce cell viability by itself, this compound potentiates Pacl proapoptotic effects. Notably, the increase of NGB levels by NGB expression vector transfection prevents Pacl or Res/Pacl effects. Taken together, these findings indicate a new Res-based mechanism that acts on tumor cells impairing the E2/ERα/NGB signaling pathways and increasing cancer cell susceptibility to chemotherapeutic agent.

Initial Priming on Soft Substrates Enhances Subsequent Topography-Induced Neuronal Differentiation in ESCs but Not in MSCs

Differentiation of stem cells into neurogenic lineage is of great interest for treatment of neurodegenerative diseases. While the role of chemical cues in regulating stem cell fate is well appreciated, the identification of physical cues has revolutionized the field of tissue engineering leading to development of scaffolds encoding one or more physical cues for inducing stem cell differentiation. In this study, using human mesenchymal stem cells (hMSCs) and mouse embryonic stem cells (mESCs), we have tested if stiffness and topography can be collectively tuned for inducing neuronal differentiation by culturing these cells on polyacrylamide hydrogels of varying stiffness (5, 10, and 20 kPa) containing rectangular grooves (10, 15, and 25 μm in width). While hMSCs maximally elongate and express neuronal markers on soft 5 kPa gels containing 10/15 μm grooves, single mESCs are unable to sense topographical features when cultured directly on grooved gels. However, this inability to sense topography is rescued by priming mESCs initially on soft 1 kPa flat gels and then replating these cells onto the grooved gels. Compared to direct culture on the grooved gels, this sequential adaptation increases both viability as well as neuronal differentiation. However, this two-step process does not enhance neuronal marker expression in hMSCs. In addition to highlighting important differences between hMSCs and mESCs in their responsiveness to physical cues, our study suggests that conditioning on soft substrates is essential for inducing topography-mediated neuronal differentiation in mESCs.

Fluoxetine Affects Differentiation of Midbrain Dopaminergic Neurons In Vitro

Recent meta-analyses found an association between prenatal exposure to the antidepressant fluoxetine (FLX) and an increased risk of autism in children. This developmental disorder has been related to dysfunctions in the brains' rewards circuitry, which, in turn, has been linked to dysfunctions in dopaminergic (DA) signaling. The present study investigated if FLX affects processes involved in dopaminergic neuronal differentiation. Mouse neuronal precursors were differentiated into midbrain dopaminergic precursor cells (mDPCs) and concomitantly exposed to clinically relevant doses of FLX. Subsequently, dopaminergic precursors were evaluated for expression of differentiation and stemness markers using quantitative polymerase chain reaction. FLX treatment led to increases in early regional specification markers orthodenticle homeobox 2 (Otx2) and homeobox engrailed-1 and -2 (En1 and En2). On the other hand, two transcription factors essential for midbrain dopaminergic (mDA) neurogenesis, LIM homeobox transcription factor 1 α (Lmx1a) and paired-like homeodomain transcription factor 3 (Pitx3) were downregulated by FLX treatment. The stemness marker nestin (Nes) was increased, whereas the neuronal differentiation marker β3-tubulin (Tubb3) decreased. Additionally, we observed that FLX modulates the expression of several genes associated with autism spectrum disorder and downregulates the estrogen receptors (ERs) α and β Further investigations using ERβ knockout (BERKO) mDPCs showed that FLX had no or even opposite effects on several of the genes analyzed. These findings suggest that FLX affects differentiation of the dopaminergic system by increasing production of dopaminergic precursors, yet decreasing their maturation, partly via interference with the estrogen system.