scholarly journals Estrogen Receptor α Signaling in Osteoblasts is Required for Mechanotransduction in Bone Fracture Healing

2021 ◽  
Vol 9 ◽  
Author(s):  
Lena Steppe ◽  
Benjamin Thilo Krüger ◽  
Miriam Eva Angelica Tschaffon ◽  
Verena Fischer ◽  
Jan Tuckermann ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Fracture Healing ◽  
Critical Role ◽  
Cell Types ◽  
Estrogen Receptor Α ◽  
Whole Body ◽  
Fracture Callus ◽  
Positive Effects ◽  
Osteoblast Lineage

Biomechanical stimulation by whole-body low-magnitude high-frequency vibration (LMHFV) has demonstrated to provoke anabolic effects on bone metabolism in both non-osteoporotic and osteoporotic animals and humans. However, preclinical studies reported that vibration improved fracture healing and bone formation in osteoporotic, ovariectomized (OVX) mice representing an estrogen-deficient hormonal status, but impaired bone regeneration in skeletally healthy non-OVX mice. These effects were abolished in general estrogen receptor α (ERα)-knockout (KO) mice. However, it remains to be elucidated which cell types in the fracture callus are targeted by LMHFV during bone healing. To answer this question, we generated osteoblast lineage-specific ERα-KO mice that were subjected to ovariectomy, femur osteotomy and subsequent vibration. We found that the ERα specifically on osteoblastic lineage cells facilitated the vibration-induced effects on fracture healing, because in osteoblast lineage-specific ERα-KO (ERαfl/fl; Runx2Cre) mice the negative effects in non-OVX mice were abolished, whereas the positive effects of vibration in OVX mice were reversed. To gain greater mechanistic insights, the influence of vibration on murine and human osteogenic cells was investigated in vitro by whole genome array analysis and qPCR. The results suggested that particularly canonical WNT and Cox2/PGE2 signaling is involved in the mechanotransduction of LMHFV under estrogen-deficient conditions. In conclusion, our study demonstrates a critical role of the osteoblast lineage-specific ERα in LMHFV-induced effects on fracture healing and provides further insights into the molecular mechanism behind these effects.

Estrogen receptor α- (ERα), but not ERβ-signaling, is crucially involved in mechanostimulation of bone fracture healing by whole-body vibration

Bone ◽  
2018 ◽  
Vol 110 ◽  
pp. 11-20 ◽  
Author(s):  
Melanie Haffner-Luntzer ◽  
Anna Kovtun ◽  
Ina Lackner ◽  
Yvonne Mödinger ◽  
Steffen Hacker ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Fracture Healing ◽  
Bone Fracture ◽  
Whole Body Vibration ◽  
Estrogen Receptor Α ◽  
Whole Body ◽  
Bone Fracture Healing ◽  
Body Vibration

scholarly journals Estrogen Receptor α and β in Mouse: Adipose-Derived Stem Cell Proliferation, Migration, and Brown Adipogenesis In Vitro

2016 ◽  
Vol 38 (6) ◽  
pp. 2285-2299 ◽  
Author(s):  
Wentian Zhang ◽  
Sebastian Schmull ◽  
Mingjun Du ◽  
Jianfang Liu ◽  
Zhexin Lu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Estrogen Receptor ◽  
Stem Cell ◽  
Critical Role ◽  
Estrogen Receptor Α ◽  
Ppar Γ ◽  
Brown Adipose ◽  
And Migration ◽  
Proliferation And Migration

Background/Aims: Adipose-derived stem cells (ASCs) belong to mesenchymal stem cells and may play a potential role as seeding cells in stem cell transplantation. To be able to exploit stem cells as therapeutic tool, their defects in some important cellular functions, such as low survival rate and cellular activity, should be considered. This is especially the case for stem cells that are intended for transplantation. Of note, stem cell responses to hormones should be considered since estrogen is known to play a critical role in stem cell behavior. However, different impacts of the estrogen receptor (ER) types α and β have not been fully determined in ASC function. In this study, we investigated effects of ERα and ERβ on ASC proliferation, migration, as well as in adipogenesis. Methods: ASCs obtained from mice were cultured with 100nM ERα or ERβ agonist PPT and DPN, respectively. The ERα and ERβ antagonist ICI 182,780 (100nM) was used as control. Results: Compared to ERβ, ERα appears more potent in improving ASC proliferation and migration. Investigation of adipogenesis revealed that ERβ played a significant role in suppressing ASC-mediated brown tissue adipogenesis which is in contrast to ERα. These results correlated with reduced mRNA expression of UCP-1, PGC-1α and PPAR-γ. Conclusions: ERα plays a more critical role in promoting ASC proliferation and migration while ERβ is more potent in suppressing ASC brown adipose tissue differentiation mediated by decreased UCP-1, PGC-1α and PPAR-γ expression.

scholarly journals AKT Alters Genome-Wide Estrogen Receptor α Binding and Impacts Estrogen Signaling in Breast Cancer

2008 ◽  
Vol 28 (24) ◽  
pp. 7487-7503 ◽  
Author(s):  
Poornima Bhat-Nakshatri ◽  
Guohua Wang ◽  
Hitesh Appaiah ◽  
Nikhil Luktuke ◽  
Jason S. Carroll ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Binding Sites ◽  
Transforming Growth Factor ◽  
Cell Types ◽  
Estrogen Receptor Α ◽  
Estrogen Signaling ◽  
Primary Tumors ◽  
Genome Wide ◽  
Extracellular Signal

ABSTRACT Estrogen regulates several biological processes through estrogen receptor α (ERα) and ERβ. ERα-estrogen signaling is additionally controlled by extracellular signal activated kinases such as AKT. In this study, we analyzed the effect of AKT on genome-wide ERα binding in MCF-7 breast cancer cells. Parental and AKT-overexpressing cells displayed 4,349 and 4,359 ERα binding sites, respectively, with ∼60% overlap. In both cell types, ∼40% of estrogen-regulated genes associate with ERα binding sites; a similar percentage of estrogen-regulated genes are differentially expressed in two cell types. Based on pathway analysis, these differentially estrogen-regulated genes are linked to transforming growth factor β (TGF-β), NF-κB, and E2F pathways. Consistent with this, the two cell types responded differently to TGF-β treatment: parental cells, but not AKT-overexpressing cells, required estrogen to overcome growth inhibition. Combining the ERα DNA-binding pattern with gene expression data from primary tumors revealed specific effects of AKT on ERα binding and estrogen-regulated expression of genes that define prognostic subgroups and tamoxifen sensitivity of ERα-positive breast cancer. These results suggest a unique role of AKT in modulating estrogen signaling in ERα-positive breast cancers and highlights how extracellular signal activated kinases can change the landscape of transcription factor binding to the genome.

scholarly journals The Phosphorylated Estrogen Receptor α (ER) Cistrome Identifies a Subset of Active Enhancers Enriched for Direct ER-DNA Binding and the Transcription Factor GRHL2

2018 ◽  
Vol 39 (3) ◽  
Author(s):  
Kyle T. Helzer ◽  
Mary Szatkowski Ozers ◽  
Mark B. Meyer ◽  
Nancy A. Benkusky ◽  
Natalia Solodin ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Transcription Factor ◽  
Dna Binding ◽  
Protein Interactions ◽  
Posttranslational Modifications ◽  
Binding Sites ◽  
Protein Function ◽  
Estrogen Receptor Α ◽  
Binding Activity

ABSTRACT Posttranslational modifications are key regulators of protein function, providing cues that can alter protein interactions and cellular location. Phosphorylation of estrogen receptor α (ER) at serine 118 (pS118-ER) occurs in response to multiple stimuli and is involved in modulating ER-dependent gene transcription. While the cistrome of ER is well established, surprisingly little is understood about how phosphorylation impacts ER-DNA binding activity. To define the pS118-ER cistrome, chromatin immunoprecipitation sequencing was performed on pS118-ER and ER in MCF-7 cells treated with estrogen. pS118-ER occupied a subset of ER binding sites which were associated with an active enhancer mark, acetylated H3K27. Unlike ER, pS118-ER sites were enriched in GRHL2 DNA binding motifs, and estrogen treatment increased GRHL2 recruitment to sites occupied by pS118-ER. Additionally, pS118-ER occupancy sites showed greater enrichment of full-length estrogen response elements relative to ER sites. In an in vitro DNA binding array of genomic binding sites, pS118-ER was more commonly associated with direct DNA binding events than indirect binding events. These results indicate that phosphorylation of ER at serine 118 promotes direct DNA binding at active enhancers and is a distinguishing mark for associated transcription factor complexes on chromatin.

scholarly journals Heterogeneity of murine periosteum osteochondroprogenitors involved in fracture healing

2020 ◽  
Author(s):  
Brya G Matthews ◽  
Francesca V Sbrana ◽  
Sanja Novak ◽  
Jessica L. Funnell ◽  
Ye Cao ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Progenitor Cells ◽  
Progenitor Cell ◽  
Callus Formation ◽  
Lineage Tracing ◽  
Fracture Callus ◽  
Stem And Progenitor Cells ◽  
Periosteal Cells ◽  
Osteoblast Lineage

AbstractThe periosteum is the major source of cells involved in fracture healing. We sought to characterize differences in progenitor cell populations between periosteum and other bone compartments, and identify periosteal cells involved in fracture healing. The periosteum is highly enriched for progenitor cells, including Sca1+ cells, CFU-F and label-retaining cells. Lineage tracing with αSMACreER identifies periosteal cells that contribute to >80% of osteoblasts and ~40% of chondrocytes following fracture. A subset of αSMA+ cells are quiescent long-term injury-responsive progenitors. Ablation of αSMA+ cells impairs fracture callus formation. In addition, committed osteoblast-lineage cells contributed around 10% of osteoblasts, but no chondrocytes in fracture calluses. Most periosteal progenitors, particularly those that form osteoblasts, can be targeted by αSMACreER. We have demonstrated that the periosteum is highly enriched for skeletal stem and progenitor cells and there is heterogeneity in the populations of cells that contribute to mature lineages during periosteal fracture healing.

scholarly journals Hematopoietic Wnts Modulate Endochondral Ossification During Fracture Healing

2021 ◽  
Vol 12 ◽  
Author(s):  
Kenon Chua ◽  
Victor K. Lee ◽  
Cheri Chan ◽  
Andy Yew ◽  
Eric Yeo ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Knockout Mice ◽  
Bone Repair ◽  
Critical Role ◽  
Computer Assisted ◽  
Stress Tests ◽  
Fracture Callus ◽  
Normal Bone ◽  
Musculoskeletal Development ◽  
Bone Quantity

Wnt signaling plays a critical role in bone formation, homeostasis, and injury repair. Multiple cell types in bone have been proposed to produce the Wnts required for these processes. The specific role of Wnts produced from cells of hematopoietic origin has not been previously characterized. Here, we examined if hematopoietic Wnts play a role in physiological musculoskeletal development and in fracture healing. Wnt secretion from hematopoietic cells was blocked by genetic knockout of the essential Wnt modifying enzyme PORCN, achieved by crossing Vav-Cre transgenic mice with Porcnflox mice. Knockout mice were compared with their wild-type littermates for musculoskeletal development including bone quantity and quality at maturation. Fracture healing including callus quality and quantity was assessed in a diaphyseal fracture model using quantitative micro computer-assisted tomographic scans, histological analysis, as well as biomechanical torsional and 4-point bending stress tests. The hematopoietic Porcn knockout mice had normal musculoskeletal development, with normal bone quantity and quality on micro-CT scans of the vertebrae. They also had normal gross skeletal dimensions and normal bone strength. Hematopoietic Wnt depletion in the healing fracture resulted in fewer osteoclasts in the fracture callus, with a resultant delay in callus remodeling. All calluses eventually progressed to full maturation. Hematopoietic Wnts, while not essential, modulate osteoclast numbers during fracture healing. These osteoclasts participate in callus maturation and remodeling. This demonstrates the importance of diverse Wnt sources in bone repair.

scholarly journals Membrane Estrogen Receptor-Dependent Extracellular Signal-Regulated Kinase Pathway Mediates Acute Activation of Endothelial Nitric Oxide Synthase by Estrogen in Uterine Artery Endothelial Cells

Endocrinology ◽  
2004 ◽  
Vol 145 (1) ◽  
pp. 113-125 ◽  
Author(s):  
Dong-bao Chen ◽  
Ian M. Bird ◽  
Jing Zheng ◽  
Ronald R. Magness
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Estrogen Receptor ◽  
Plasma Membrane ◽  
Uterine Artery ◽  
Fluorescein Isothiocyanate ◽  
Estrogen Receptor Α ◽  
Dependent Manner ◽  
Enos Phosphorylation

Abstract Rapid uterine vasodilatation after estrogen administration is believed to be mediated by endothelial production of nitric oxide (NO) via endothelial NO synthase (eNOS). However, the mechanism(s) by which estrogen activates eNOS in uterine artery endothelial cells (UAEC) is unknown. In this study, we observed that estradiol-17β (E2) and E2-BSA rapidly (<2 min) increased total NOx production in UAEC in vitro. This was associated with rapid eNOS phosphorylation and activation but was unaltered by pretreatment with actinomycin-D. estrogen receptor-α protein was detectable in isolated plasma membrane proteins by immunoblotting, and E2-BSA-fluorescein isothiocyanate binding was evident on the plasma membrane of UAEC. E2 did not mobilize intracellular Ca2+, but E2 and ionomycin in combination induced greater eNOS phosphorylation than either E2 or ionomycin alone. E2 did not stimulate rapid Akt phosphorylation. E2 stimulated rapid ERK2/1 activation in a time- and dose-dependent manner, with maximal responses observed at 5–10 min with E2 (10 nm to 1 μm) treatment. Acute activation of eNOS and NOx production by E2 could be inhibited by PD98059 but not by LY294002. When E2-BSA was applied, similar responses in NOx production, eNOS, and ERK2/1 activation to those of E2 were achieved. In addition, E2 and E2-BSA-induced ERK2/1 activation and ICI 182,780 could inhibit NOx production by E2. Thus, acute activation of eNOS to produce NO in UAEC by estrogen is at least partially through an ERK pathway, possibly via estrogen receptor localized on the plasma membrane. This pathway may provide a novel mechanism for NO-mediated rapid uterine vasodilatation by estrogen.

LncRNA MALAT1 exhibits positive effects on nucleus pulposus cell biology in vivo and in vitro by sponging miR-503

2020 ◽  
Author(s):  
Hongyu Zheng ◽  
Tingting Wang ◽  
Xiangmin Li ◽  
Wei He ◽  
Zhiqiang Gong ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Disc Degeneration ◽  
Cell Biology ◽  
Mapk Pathway ◽  
Critical Role ◽  
Mapk Signaling ◽  
Positive Effects ◽  
Lncrna Malat1

Abstract Background: Intervertebral disc degeneration (IDD) is characterized by the loss of nucleus pulposus cells (NPCs) and phenotypic abnormalities. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) are involved in the pathogenesis of IDD. In this study, we aimed to investigate the functional effects of lncRNA MALAT1 on NPCs in IDD and the possible mechanism governing these effects. Results: We validated the decreased expression of MALAT1 in the IDD tissues, which was associated with decreased Collagen II and Aggrecan expression. In vitro, overexpressed MALAT1 could attenuate the effect of IL-1β on NPC proliferation, apoptosis, and Aggrecan degradation. In vivo, MALAT1 overexpression attenuated the severity of disc degeneration in IDD model rats. Our molecular study further demonstrated that MALAT1 could sponge miR-503, modulate the expression of miR-503, and activate downstream MAPK signaling pathways. The effects of MALAT1 on NPCs were partially reversed/aggregated by miR-503 mimics/inhibitor treatment. Conclusion: Our data suggested that the MALAT1-miR-503-MAPK pathway plays a critical role in NPCs, which may be a potential strategy for alleviating IDD.

scholarly journals Comparative study of estrogen receptor α, β mRNA expressions of endometriosis and normal endometrium in women and analysis of potential synthetic anti-estrogens in silico

2018 ◽  
Vol 91 (2) ◽  
Author(s):  
Eldafira Eldafira ◽  
Abinawanto Abinawanto ◽  
Luthfiralda Sjahfirdi ◽  
Asmarinah Asmarinah ◽  
Purnomo Soeharso ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Mrna Expression ◽  
Estrogen Receptor Α ◽  
Assay Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Normal Endometrium ◽  
Pcr Method ◽  
Genetic And Environmental Factors

Endometriosis is a multifactorial disease in which genetic and environmental factors interact causing its pathogenesis. The aim of this study was to investigate the expression pattern of estrogen receptor α (ERα) and β (ERβ) in endometriosis patients compared to normal endometrioum (n=18) as a control by using Quantitative Real Time PCR method. Moreover, we also measured serum estradiol levels of endometriosis patients in the proliferation phase of the menstrual cycle using the enzyme-linked immunosorbent assay method. The mRNA expression of ERβ was significantly higher in the endometriosis group compared to control, and the result of t-test showed that were significantly different (P<0.05). Overexpression of ERβ in endometriosis was likely to have other significant important impacts in the pathology of endometriosis that allowed ERβ to stimulate prostaglandin production in endometriosis tissue and cells. Estradiol content did not correlate with the ERα expression, and it is weakly correlated with ERβ mRNA expression. Molecular docking analysis showed that ERα and ERβ have different binding interactions with synthetic antiestrogens, whereas the best inhibitor was Ral2 to ERα and Aco1 to ERβ. Thus, both inhibitors could be used as leads in further investigation of ERα, ERβ inhibitory activities in vitro and in vivo.

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