scholarly journals Postlesion Estradiol Treatment Increases Cortical Cholinergic Innervations via Estrogen Receptor-α Dependent Nonclassical Estrogen Signaling in Vivo

Endocrinology ◽  
2011 ◽  
Vol 152 (9) ◽  
pp. 3471-3482 ◽  
Author(s):  
Zsombor Kőszegi ◽  
Éva M. Szegő ◽  
Rachel Y. Cheong ◽  
Emeline Tolod-Kemp ◽  
István M. Ábrahám
Keyword(s):  
Estrogen Receptor ◽  
Protein Kinase ◽  
Cell Loss ◽  
Estrogen Receptor Α ◽  
Estrogen Signaling ◽  
Ovariectomized Mice ◽  
Cholinergic Cell ◽  
Kinase A

17β-Estradiol (E2) treatment exerts rapid, nonclassical actions via intracellular signal transduction system in basal forebrain cholinergic (BFC) neurons in vivo. Here we examined the effect of E2 treatment on lesioned BFC neurons in ovariectomized mice and the role of E2-induced nonclassical action in this treatment. Mice given an N-methyl-d-aspartic acid (NMDA) injection into the substantia innominata-nucleus basalis magnocellularis complex (SI-NBM) exhibited cholinergic cell loss in the SI-NBM and ipsilateral cholinergic fiber loss in the cortex. A single injection of E2 after NMDA lesion did not have an effect on cholinergic cell loss in the SI-NBM, but it restored the ipsilateral cholinergic fiber density in the cortex in a time- and dose-dependent manner. The most effective cholinergic fiber restoration was observed with 33 ng/g E2 treatment at 1 h after NMDA lesion. The E2-induced cholinergic fiber restoration was absent in neuron-specific estrogen receptor-α knockout mice in vivo. Selective activation of nonclassical estrogen signaling in vivo by estren induced E2-like restorative actions. Selective blockade of the MAPK or protein kinase A pathway in vivo prevented E2's ability to restore cholinergic fiber loss. Finally, studies in intact female mice revealed an E2-induced restorative effect that was similar to that of E2-treated ovariectomized mice. These observations demonstrate that a single E2 treatment restores the BFC fiber loss in the cortex, regardless of endogenous E2 levels. They also reveal the critical role of nonclassical estrogen signaling via estrogen receptor-α and protein kinase A-MAPK pathways in E2-induced restorative action in the cholinergic system in vivo.

scholarly journals Estrogen Receptor (ER)-β Reduces ERα-Regulated Gene Transcription, Supporting a “Ying Yang” Relationship between ERα and ERβ in Mice

2003 ◽  
Vol 17 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Marie K. Lindberg ◽  
Sofia Movérare ◽  
Stanko Skrtic ◽  
Hui Gao ◽  
Karin Dahlman-Wright ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Gene Transcription ◽  
Physiological Role ◽  
Estrogen Receptor Α ◽  
Mrna Levels ◽  
Wild Type ◽  
Ovariectomized Mice ◽  
Adult Bone

Abstract Estrogen is of importance for the regulation of adult bone metabolism. The aim of the present study was to determine the role of estrogen receptor-β (ERβ) in vivo on global estrogen-regulated transcriptional activity in bone. The effect of estrogen in bone of ovariectomized mice was determined using microarray analysis including 9400 genes. Most of the genes (95% = 240 genes) that were increased by estrogen in wild-type (WT) mice were also increased by estrogen in ERβ-inactivated mice. Interestingly, the average stimulatory effect of estrogen on the mRNA levels of these genes was 85% higher in ERβ-inactivated than in WT mice, demonstrating that ERβ reduces estrogen receptor-α (ERα)-regulated gene transcription in bone. The average stimulatory effect of estrogen on estrogen-regulated bone genes in ERα-inactivated mice was intermediate between that seen in WT and ERαβ double-inactivated mice. Thus, ERβ inhibits ERα-mediated gene transcription in the presence of ERα, whereas, in the absence of ERα, it can partially replace ERα. In conclusion, our in vivo data indicate that an important physiological role of ERβ is to modulate ERα-mediated gene transcription supporting a “Ying Yang” relationship between ERα and ERβ in mice.

Membrane estrogen receptor α is essential for estrogen signaling in the male skeleton

2018 ◽  
Vol 239 (3) ◽  
pp. 303-312 ◽  
Author(s):  
H H Farman ◽  
K L Gustafsson ◽  
P Henning ◽  
L Grahnemo ◽  
V Lionikaite ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Estrogen Receptor Α ◽  
Estrogen Signaling ◽  
Areal Bone Mineral Density ◽  
Male Mice ◽  
Mineral Density ◽  
Intact Male ◽  
Trabecular Thickness ◽  
Total Body

The importance of estrogen receptor α (ERα) for the regulation of bone mass in males is well established. ERα mediates estrogenic effects both via nuclear and membrane-initiated ERα (mERα) signaling. The role of mERα signaling for the effects of estrogen on bone in male mice is unknown. To investigate the role of mERα signaling, we have used mice (Nuclear-Only-ER; NOER) with a point mutation (C451A), which results in inhibited trafficking of ERα to the plasma membrane. Gonadal-intact male NOER mice had a significantly decreased total body areal bone mineral density (aBMD) compared to WT littermates at 3, 6 and 9 months of age as measured by dual-energy X-ray absorptiometry (DEXA). High-resolution microcomputed tomography (µCT) analysis of tibia in 3-month-old males demonstrated a decrease in cortical and trabecular thickness in NOER mice compared to WT littermates. As expected, estradiol (E2) treatment of orchidectomized (ORX) WT mice increased total body aBMD, trabecular BV/TV and cortical thickness in tibia compared to placebo treatment. E2 treatment increased these skeletal parameters also in ORX NOER mice. However, the estrogenic responses were significantly decreased in ORX NOER mice compared with ORX WT mice. In conclusion, mERα is essential for normal estrogen signaling in both trabecular and cortical bone in male mice. Increased knowledge of estrogen signaling mechanisms in the regulation of the male skeleton may aid in the development of new treatment options for male osteoporosis.

scholarly journals Phosphorylation of Human Estrogen Receptor α by Protein Kinase A Regulates Dimerization

1999 ◽  
Vol 19 (2) ◽  
pp. 1002-1015 ◽  
Author(s):  
Dongsheng Chen ◽  
Paul E. Pace ◽  
R. Charles Coombes ◽  
Simak Ali
Keyword(s):  
Estrogen Receptor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Ligand Binding ◽  
Protein Kinase A ◽  
Estrogen Receptor Α ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Ici 182,780 ◽  
Kinase A

ABSTRACT Phosphorylation provides an important mechanism by which transcription factor activity is regulated. Estrogen receptor α (ERα) is phosphorylated on multiple sites, and stimulation of a number of growth factor receptors and/or protein kinases leads to ligand-independent and/or synergistic increase in transcriptional activation by ERα in the presence of estrogen. Here we show that ERα is phosphorylated by protein kinase A (PKA) on serine-236 within the DNA binding domain. Mutation of serine-236 to glutamic acid prevents DNA binding by inhibiting dimerization by ERα, whereas mutation to alanine has little effect on DNA binding or dimerization. Furthermore, PKA overexpression or activation of endogenous PKA inhibits dimerization in the absence of ligand. This inhibition is overcome by the addition of 17β-estradiol or the partial agonist 4-hydroxy tamoxifen. Interestingly, treatment with the complete antagonist ICI 182,780 does not overcome the inhibitory effect of PKA activation. Our results indicate that in the absence of ligand ERα forms dimers through interaction between DNA binding domains and that dimerization mediated by the ligand binding domain only occurs upon ligand binding but that the complete antagonist ICI 182,780 prevents dimerization through the ligand-binding domain. Heterodimer formation between ERα and ERβ is similarly affected by PKA phosphorylation of serine 236 of ERα. However, 4-hydroxytamoxifen is unable to overcome inhibition of dimerization by PKA. Thus, phosphorylation of ERα in the DNA binding domain provides a mechanism by which dimerization and thereby DNA binding by the estrogen receptor is regulated.

scholarly journals miR-22 Inhibits Estrogen Signaling by Directly Targeting the Estrogen Receptor α mRNA

2009 ◽  
Vol 29 (13) ◽  
pp. 3783-3790 ◽  
Author(s):  
Deo Prakash Pandey ◽  
Didier Picard
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Breast Cancer Cells ◽  
Estrogen Receptor Α ◽  
Estrogen Signaling ◽  
Systematic Assessment ◽  
Small Noncoding Rnas ◽  
Evolutionarily Conserved ◽  
Target Sites

ABSTRACT Estrogen receptor α (ERα) is a ligand-regulated transcription factor with a broad range of physiological functions and one of the most important classifiers in breast cancer. MicroRNAs (miRNAs) are small noncoding RNAs that have emerged as important regulators of gene expression in a plethora of physiological and pathological processes. Upon binding the 3′ untranslated region (UTR) of target mRNAs, miRNAs typically reduce their stability and/or translation. The ERα mRNA has a long 3′ UTR of about 4.3 kb which has been reported to reduce mRNA stability and which bears evolutionarily conserved miRNA target sites, suggesting that it might be regulated by miRNAs. We have performed a comprehensive and systematic assessment of the regulatory role of all miRNAs that are predicted to target the 3′ UTR of the ERα mRNA. We found that miR-22 represses ERα expression most strongly and by directly targeting the ERα mRNA 3′ UTR. Of the three predicted miR-22 target sites in the 3′ UTR, the evolutionarily conserved one is the primary target. miR-22 overexpression leads to a reduction of ERα levels, at least in part by inducing mRNA degradation, and compromises estrogen signaling, as exemplified by its inhibitory impact on the ERα-dependent proliferation of breast cancer cells.

scholarly journals Both Estrogen Receptor α and β Stimulate Pituitary GH Gene Expression

2014 ◽  
Vol 28 (1) ◽  
pp. 40-52 ◽  
Author(s):  
Dimiter Avtanski ◽  
Horacio J. Novaira ◽  
Sheng Wu ◽  
Christopher J. Romero ◽  
Rhonda Kineman ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Mrna Expression ◽  
Transcriptional Control ◽  
Estrogen Receptor Α ◽  
In Vitro Models ◽  
Mrna Levels ◽  
Ovariectomized Mice ◽  
Serum Gh

Abstract Although sex steroids have been implicated in the control of mammalian growth, their direct effect on GH synthesis is less clear. The aim of this study was to establish whether estradiol (E2) directly affects GH synthesis in somatotrophs. Somatotroph GH3 and MtT/S cells were used as in vitro models. At physiological doses of E2 stimulation, GH mRNA levels were increased and the ER antagonist ICI 182,780 completely abolished this effect. Estrogen receptor (ER) α– and ERβ-selective agonists, propylpyrazole triol (PPT), and 2,3-bis(4-hydroxyphenyl) propionitrile (DPN), respectively, augmented GH mRNA expression and secretion, whereas E2 and PPT, but not DPN increased prolactin (PRL) mRNA levels. E2, PPT, and DPN stimulated expression of the pituitary transcription factor Pou1f1 and increased its binding to the GH promoter. In vivo evidence of E2 effects on GH synthesis was obtained from the generation of the somatotroph-specific ERα knockout (sERα-KO) mouse model. Basal pituitary GH, PRL, POU1F1, and ERα mRNA expression levels were lower in sERα-KO mice compared with those in controls; whereas ERβ mRNA levels remained unchanged. E2 and DPN stimulated pituitary GH mRNA expression and serum GH levels in control and sERα-KO ovariectomized mice; however, serum GH levels were unchanged in PPT-treated ovariectomized sERα-KO mice. In these animal models, PRL mRNA levels increased after either E2 or PPT, but an increase was not seen after DPN treatment. Thus, we propose a mechanism by which estrogen directly regulates somatotroph GH synthesis at a pretranslational level. In contrast to the predominant effect of ERα in the lactotroph, these results support a role for both ERα and ERβ in the transcriptional control of Gh in the somatotroph and illustrate important differences in ER isoform specificity in the anterior pituitary gland.

Implications of estrogen receptor alpha and estrogen receptor beta for adipose tissue functions and cardiometabolic complications

2013 ◽  
Vol 15 (3) ◽  
Author(s):  
Hui Gao ◽  
Karin Dahlman-Wright
Keyword(s):  
Estrogen Receptor ◽  
Adipose Tissue ◽  
Estrogen Receptor Alpha ◽  
Molecular Mechanisms ◽  
Estrogen Receptor Beta ◽  
Estrogen Receptor Α ◽  
Endocrine Function ◽  
Estrogen Signaling ◽  
Strongly Connected

AbstractThere is growing evidence that estrogen signaling regulates energy metabolism and exerts important functions in maintaining adipose tissue metabolism, including controlling the distribution of body fat. Changes in the physiological functions of adipose tissue, particularly the white adipose tissue, have been strongly connected to obesity and the development of related cardiometabolic complications. In this review, we will focus on discussing the role of estrogen signaling in regulating adipocyte differentiation, metabolism and its endocrine function with a focus on the possible underlying molecular mechanisms mediated by estrogen receptor α and estrogen receptor β.

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