scholarly journals Neonatal Inhibition of DNA Methylation Disrupts Testosterone-Dependent Masculinization of Neurochemical Phenotype

Endocrinology ◽  
2019 ◽  
Vol 161 (1) ◽  
Author(s):  
Carla D Cisternas ◽  
Laura R Cortes ◽  
Ilona Golynker ◽  
Alexandra Castillo-Ruiz ◽  
Nancy G Forger
Keyword(s):  
Dna Methylation ◽  
Sex Differences ◽  
Estrogen Receptor Alpha ◽  
Molecular Mechanisms ◽  
Preoptic Area ◽  
Cell Types ◽  
Cell Number ◽  
Cell Phenotype ◽  
Stria Terminalis ◽  
Bed Nucleus

Abstract Many neural sex differences are differences in the number of neurons of a particular phenotype. For example, male rodents have more calbindin-expressing neurons in the medial preoptic area (mPOA) and bed nucleus of the stria terminalis (BNST), and females have more neurons expressing estrogen receptor alpha (ERα) and kisspeptin in the ventromedial nucleus of the hypothalamus (VMH) and the anteroventral periventricular nucleus (AVPV), respectively. These sex differences depend on neonatal exposure to testosterone, but the underlying molecular mechanisms are unknown. DNA methylation is important for cell phenotype differentiation throughout the developing organism. We hypothesized that testosterone causes sex differences in neurochemical phenotype via changes in DNA methylation, and tested this by inhibiting DNA methylation neonatally in male and female mice, and in females given a masculinizing dose of testosterone. Neonatal testosterone treatment masculinized calbindin, ERα and kisspeptin cell number of females at weaning. Inhibiting DNA methylation with zebularine increased calbindin cell number only in control females, thus eliminating sex differences in calbindin in the mPOA and BNST. Zebularine also reduced the sex difference in ERα cell number in the VMH, in this case by increasing ERα neuron number in males and testosterone-treated females. In contrast, the neonatal inhibition of DNA methylation had no effect on kisspeptin cell number. We conclude that testosterone normally increases the number of calbindin cells and reduces ERα cells in males through orchestrated changes in DNA methylation, contributing to, or causing, the sex differences in both cell types.

scholarly journals Epigenetic Control of Sexual Differentiation of the Bed Nucleus of the Stria Terminalis

Endocrinology ◽  
2009 ◽  
Vol 150 (9) ◽  
pp. 4241-4247 ◽  
Author(s):  
Elaine K. Murray ◽  
Annie Hien ◽  
Geert J. de Vries ◽  
Nancy G. Forger
Keyword(s):  
Cell Death ◽  
Sex Differences ◽  
Sexual Differentiation ◽  
Cell Number ◽  
Histone Deacetylation ◽  
Postnatal Life ◽  
Sexually Dimorphic ◽  
Stria Terminalis ◽  
Bed Nucleus ◽  
Deacetylase Inhibitor

Abstract The principal nucleus of the bed nucleus of the stria terminalis (BNSTp) is larger in volume and contains more cells in male than female mice. These sex differences depend on testosterone and arise from a higher rate of cell death during early postnatal life in females. There is a delay of several days between the testosterone surge at birth and sexually dimorphic cell death in the BNSTp, suggesting that epigenetic mechanisms may be involved. We tested the hypothesis that chromatin remodeling plays a role in sexual differentiation of the BNSTp by manipulating the balance between histone acetylation and deacetylation using a histone deacetylase inhibitor. In the first experiment, a single injection of valproic acid (VPA) on the day of birth increased acetylation of histone H3 in the brain 24 h later. Next, males, females, and females treated neonatally with testosterone were administered VPA or saline on postnatal d 1 and 2 and killed at 21 d of age. VPA treatment did not influence volume or cell number of the BNSTp in control females but significantly reduced both parameters in males and testosterone-treated females. As a result, the sex differences were eliminated. VPA did not affect volume or cell number in the suprachiasmatic nucleus or the anterodorsal nucleus of the thalamus, which also did not differ between males and females. These findings suggest that a disruption in histone deacetylation may lead to long-term alterations in gene expression that block the masculinizing actions of testosterone in the BNSTp.

scholarly journals Evolutionarily Conserved Glucocorticoid Regulation of Corticotropin-Releasing Factor Expression

Endocrinology ◽  
2008 ◽  
Vol 149 (5) ◽  
pp. 2352-2360 ◽  
Author(s):  
Meng Yao ◽  
Jay Schulkin ◽  
Robert J. Denver
Keyword(s):  
Glucocorticoid Receptor ◽  
Paraventricular Nucleus ◽  
Molecular Mechanisms ◽  
Preoptic Area ◽  
Corticotropin Releasing Factor ◽  
Stria Terminalis ◽  
Medial Amygdala ◽  
Cell Type ◽  
Synthesis Inhibitor ◽  
Bed Nucleus

Glucocorticoids (GCs) exert feedback regulation on corticotropin-releasing factor (CRF) neurons in mammals. The nature of GC actions is cell-type specific, being either inhibitory (e.g. paraventricular nucleus) or stimulatory (e.g. amygdala and bed nucleus of the stria terminalis). Nothing is known about differential regulation of CRF gene expression by GCs in nonmammalian vertebrates. We studied the actions of GCs on CRF expression in discrete brain regions of the frog Xenopus laevis. Treatment with corticosterone (CORT) decreased, whereas the corticosteroid synthesis inhibitor metyrapone increased CRF expression in the anterior preoptic area (homolog of the mammalian paraventricular nucleus), as measured by CRF primary transcript, mRNA, and CRF immunoreactivity (ir) (by immunocytochemistry). By contrast to the preoptic area, CORT increased CRF-ir in the medial amygdala and bed nucleus of the stria terminalis, whereas metyrapone decreased CRF-ir in the medial amygdala. CRF-ir and glucocorticoid receptor-ir were colocalized in cells in the frog brain. In transient transfection assays in PC-12 cells, GCs decreased forskolin-induced activation of the frog CRF promoters. Treatment with CORT also reduced CRF promoter activity in transfected tadpole brain in vivo. Frog glucocorticoid receptor bound with high-affinity in vitro to regions in the proximal promoters of frog CRF genes that are homologous with the human CRF gene. Our findings suggest that the neural cell-type specificity and molecular mechanisms of GC-dependent regulation of CRF are phylogenetically ancient, and that the limbic pathways mediating behavioral and physiological responses to stressors were likely present in the earliest land-dwelling vertebrates.

scholarly journals Sexual Differentiation of Vasopressin Innervation of the Brain: Cell Death Versus Phenotypic Differentiation

Endocrinology ◽  
2008 ◽  
Vol 149 (9) ◽  
pp. 4632-4637 ◽  
Author(s):  
Geert J. de Vries ◽  
Michelle Jardon ◽  
Mohammed Reza ◽  
Greta J. Rosen ◽  
Eleanor Immerman ◽  
...  
Keyword(s):  
Cell Death ◽  
Sex Difference ◽  
Cell Number ◽  
Lateral Septum ◽  
Projection Area ◽  
Cell Phenotype ◽  
Stria Terminalis ◽  
Phenotypic Differentiation ◽  
Bed Nucleus ◽  
Differential Cell

In most vertebrates studied, males have more vasopressin (VP) cells in the bed nucleus of the stria terminalis, or homologous vasotocin cells in nonmammalian species, than females. Previous research excluded differential cell birth and migration as likely mechanisms underlying this difference, leaving just differential cell death and phenotypic differentiation of existing cells. To differentiate between these remaining possibilities, we compared VP cell number in wild-type mice vs. mice overexpressing the anti-cell death factor, Bcl-2. All animals were gonadectomized in adulthood and given testosterone capsules. Three weeks later, brains were processed for in situ hybridization to identify VP cells. Bcl-2 overexpression increased VP cell number in both sexes but did not reduce the sex difference. We repeated this experiment in mice with a null mutation of the pro-cell death gene, Bax, and obtained similar results; cell number was increased in Bax−/− mice of both sexes, but males had about 40% more VP cells, regardless of Bax gene status. Taken together, cell death is unlikely to account for the sex difference in VP cell number, leaving differentiation of cell phenotype as the most likely underlying mechanism. We also used immunocytochemistry to examine VP projections in Bcl-2-overexpressing mice. As expected, males showed denser VP-immunoreactive fibers than females in the lateral septum, a projection area of the bed nucleus of the stria terminalis. However, even though Bcl-2 overexpression increased VP cell number, it did not affect fiber density. Thus, a compensatory mechanism may control total septal innervation regardless of the number of contributing cells.

A novel epithelial cell from neonatal rat lung: isolation and differentiated phenotype

1990 ◽  
Vol 259 (6) ◽  
pp. L415-L425 ◽  
Author(s):  
P. E. Roberts ◽  
D. M. Phillips ◽  
J. P. Mather
Keyword(s):  
Epithelial Cell ◽  
Molecular Mechanisms ◽  
Basal Medium ◽  
Fold Increase ◽  
Cell Types ◽  
Cell Number ◽  
Neonatal Rat ◽  
Rat Lung ◽  
Cell Type

A novel epithelial cell from normal neonatal rat lung has been isolated, established, and maintained for multiple passages in the absence of serum, without undergoing crisis or senescence. By careful manipulation of the nutrition/hormonal microenvironment, we have been able to select, from a heterogeneous population, a single epithelial cell type that can maintain highly differentiated features in vitro. This cell type has characteristics of bronchiolar epithelial cells. A clonal line, RL-65, has been selected and observed for greater than 2 yr in continuous culture. It has been characterized by ultrastructural, morphological, and biochemical criteria. The basal medium for this cell line is Ham's F12/Dulbecco's modified Eagle's (DME) medium plus insulin (1 micrograms/ml), human transferrin (10 micrograms/ml), ethanolamine (10(-4) M), phosphoethanolamine (10(-4) M), selenium (2.5 x 10(-8) M), hydrocortisone (2.5 x 10(-7) M), and forskolin (5 microM). The addition of 150 micrograms/ml of bovine pituitary extract to the defined basal medium stimulates a greater than 10-fold increase in cell number and a 50- to 100-fold increase in thymidine incorporation. The addition of retinoic acid results in further enhancement of cell growth and complete inhibition of keratinization. We have demonstrated a strategy that may be applicable to isolating other cell types from the lung and maintaining their differentiated characteristics for long-term culture in vitro. Such a culture system promises to be a useful model in which to study cellular events associated with differentiation and proliferation in the lung and to better understand the molecular mechanisms involved in these events.

scholarly journals LY75 Ablation Mediates Mesenchymal-Epithelial Transition (MET) in Epithelial Ovarian Cancer (EOC) Cells Associated with DNA Methylation Alterations and Suppression of the Wnt/β-Catenin Pathway

2020 ◽  
Vol 21 (5) ◽  
pp. 1848 ◽  
Author(s):  
Sadia Mehdi ◽  
Magdalena Bachvarova ◽  
Marie-Pier Scott-Boyer ◽  
Arnaud Droit ◽  
Dimcho Bachvarov
Keyword(s):  
Ovarian Cancer ◽  
Dna Methylation ◽  
Epithelial Ovarian Cancer ◽  
Molecular Mechanisms ◽  
Specific Inhibitor ◽  
Alternative Methods ◽  
Cell Phenotype ◽  
Mesenchymal Transition ◽  
Proteomic Approach ◽  
Mesenchymal Epithelial Transition

Growing evidence demonstrates that epithelial–mesenchymal transition (EMT) plays an important role in epithelial ovarian cancer (EOC) progression and spreading; however, its molecular mechanisms remain poorly defined. We have previously shown that the antigen receptor LY75 can modulate EOC cell phenotype and metastatic potential, as LY75 depletion directed mesenchymal–epithelial transition (MET) in EOC cell lines with mesenchymal phenotype. We used the LY75-mediated modulation of EMT as a model to investigate for DNA methylation changes during EMT in EOC cells, by applying the reduced representation bisulfite sequencing (RRBS) methodology. Numerous genes have displayed EMT-related DNA methylation patterns alterations in their promoter/exon regions. Ten selected genes, whose DNA methylation alterations were further confirmed by alternative methods, were further identified, some of which could represent new EOC biomarkers/therapeutic targets. Moreover, our methylation data were strongly indicative for the predominant implication of the Wnt/β-catenin pathway in the EMT-induced DNA methylation variations in EOC cells. Consecutive experiments, including alterations in the Wnt/β-catenin pathway activity in EOC cells with a specific inhibitor and the identification of LY75-interacting partners by a proteomic approach, were strongly indicative for the direct implication of the LY75 receptor in modulating the Wnt/β-catenin signaling in EOC cells.

Sign in / Sign up

Export Citation Format

Share Document