scholarly journals The Orphan Nuclear Estrogen Receptor–Related Receptor α (Errα) Is Expressed Throughout Osteoblast Differentiation and Regulates Bone Formation in Vitro

2001 ◽  
Vol 153 (5) ◽  
pp. 971-984 ◽  
Author(s):  
E. Bonnelye ◽  
L. Merdad ◽  
V. Kung ◽  
J.E. Aubin
Keyword(s):  
Estrogen Receptor ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Target Genes ◽  
Developmental Stages ◽  
Physiological Role ◽  
Orphan Receptor ◽  
Nuclear Estrogen Receptor

The orphan nuclear estrogen receptor–related receptor α (ERRα), is expressed by many cell types, but is very highly expressed by osteoblastic cells in which it transactivates at least one osteoblast-associated gene, osteopontin. To study the putative involvement of ERRα in bone, we first assessed its expression in rat calvaria (RC) in vivo and in RC cells in vitro. ERRα mRNA and protein were expressed at all developmental stages from early osteoprogenitors to bone-forming osteoblasts, but protein was most abundant in mature cuboidal osteoblasts. To assess a functional role for ERRα in osteoblast differentiation and bone formation, we blocked its expression by antisense oligonucleotides in either proliferating or differentiating RC cell cultures and found inhibition of cell growth and a proliferation-independent inhibition of differentiation. On the other hand, ERRα overexpression in RC cells increased differentiation and maturation of progenitors to mature bone-forming cells. Our findings show that ERRα is highly expressed throughout the osteoblast developmental sequence and plays a physiological role in differentiation and bone formation at both proliferation and differentiation stages. In addition, we found that manipulation of receptor levels in the absence of known ligand is a fruitful approach for functional analysis of this orphan receptor and identification of potential target genes.

Membrane and Nuclear Estrogen Receptor Alpha Actions: From Tissue Specificity to Medical Implications

2017 ◽  
Vol 97 (3) ◽  
pp. 1045-1087 ◽  
Author(s):  
Jean-Francois Arnal ◽  
Françoise Lenfant ◽  
Raphaël Metivier ◽  
Gilles Flouriot ◽  
Daniel Henrion ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Estrogen Receptor Alpha ◽  
Reproductive Tract ◽  
Vascular System ◽  
Physiological Role ◽  
Receptor Alpha ◽  
Nuclear Signaling ◽  
Nuclear Estrogen Receptor

Estrogen receptor alpha (ERα) has been recognized now for several decades as playing a key role in reproduction and exerting functions in numerous nonreproductive tissues. In this review, we attempt to summarize the in vitro studies that are the basis of our current understanding of the mechanisms of action of ERα as a nuclear receptor and the key roles played by its two activation functions (AFs) in its transcriptional activities. We then depict the consequences of the selective inactivation of these AFs in mouse models, focusing on the prominent roles played by ERα in the reproductive tract and in the vascular system. Evidence has accumulated over the two last decades that ERα is also associated with the plasma membrane and activates non-nuclear signaling from this site. These rapid/nongenomic/membrane-initiated steroid signals (MISS) have been characterized in a variety of cell lines, and in particular in endothelial cells. The development of selective pharmacological tools that specifically activate MISS and the generation of mice expressing an ERα protein impeded for membrane localization have begun to unravel the physiological role of MISS in vivo. Finally, we discuss novel perspectives for the design of tissue-selective ER modulators based on the integration of the physiological and pathophysiological roles of MISS actions of estrogens.

scholarly journals Modulating PKCα Activity to Target Wnt/β-Catenin Signaling in Colon Cancer

Cancers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 693 ◽  
Author(s):  
Sébastien Dupasquier ◽  
Philippe Blache ◽  
Laurence Picque Lasorsa ◽  
Han Zhao ◽  
Jean-Daniel Abraham ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Tumor Development ◽  
Orphan Receptor ◽  
Nuclear Accumulation ◽  
Kinase C ◽  
Extracellular Signal

Inactivating mutations of the tumor suppressor Adenomatosis Polyposis Coli (APC), which are found in familial adenomatosis polyposis and in 80% of sporadic colorectal cancers (CRC), result in constitutive activation of the Wnt/β-catenin pathway and tumor development in the intestine. These mutations disconnect the Wnt/β-catenin pathway from its Wnt extracellular signal by inactivating the APC/GSK3-β/axin destruction complex of β-catenin. This results in sustained nuclear accumulation of β-catenin, followed by β-catenin-dependent co-transcriptional activation of Wnt/β-catenin target genes. Thus, mechanisms acting downstream of APC, such as those controlling β-catenin stability and/or co-transcriptional activity, are attractive targets for CRC treatment. Protein Kinase C-α (PKCα) phosphorylates the orphan receptor RORα that then inhibits β-catenin co-transcriptional activity. PKCα also phosphorylates β-catenin, leading to its degradation by the proteasome. Here, using both in vitro (DLD-1 cells) and in vivo (C57BL/6J mice) PKCα knock-in models, we investigated whether enhancing PKCα function could be beneficial in CRC treatment. We found that PKCα is infrequently mutated in CRC samples, and that inducing PKCα function is not deleterious for the normal intestinal epithelium. Conversely, di-terpene ester-induced PKCα activity triggers CRC cell death. Together, these data indicate that PKCα is a relevant drug target for CRC treatment.

scholarly journals Hedgehog Signaling Inhibition by Smoothened Antagonist BMS-833923 Reduces Osteoblast Differentiation and Ectopic Bone Formation of Human Skeletal (Mesenchymal) Stem Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Nihal AlMuraikhi ◽  
Nuha Almasoud ◽  
Sarah Binhamdan ◽  
Ghaydaa Younis ◽  
Dalia Ali ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Global Gene Expression ◽  
Ectopic Bone Formation ◽  
Ectopic Bone ◽  
In Vitro Mineralization ◽  
Global Gene Expression Profiling

Background. Hedgehog (Hh) signaling is essential for osteoblast differentiation of mesenchymal progenitors during endochondral bone formation. However, the critical role of Hh signaling during adult bone remodeling remains to be elucidated. Methods. A Smoothened (SMO) antagonist/Hedgehog inhibitor, BMS-833923, identified during a functional screening of a stem cell signaling small molecule library, was investigated for its effects on the osteoblast differentiation of human skeletal (mesenchymal) stem cells (hMSC). Alkaline phosphatase (ALP) activity and Alizarin red staining were employed as markers for osteoblast differentiation and in vitro mineralization capacity, respectively. Global gene expression profiling was performed using the Agilent® microarray platform. Effects on in vivo ectopic bone formation were assessed by implanting hMSC mixed with hydroxyapatite-tricalcium phosphate granules subcutaneously in 8-week-old female nude mice, and the amount of bone formed was assessed using quantitative histology. Results. BMS-833923, a SMO antagonist/Hedgehog inhibitor, exhibited significant inhibitory effects on osteoblast differentiation of hMSCs reflected by decreased ALP activity, in vitro mineralization, and downregulation of osteoblast-related gene expression. Similarly, we observed decreased in vivo ectopic bone formation. Global gene expression profiling of BMS-833923-treated compared to vehicle-treated control cells, identified 348 upregulated and 540 downregulated genes with significant effects on multiple signaling pathways, including GPCR, endochondral ossification, RANK-RANKL, insulin, TNF alpha, IL6, and inflammatory response. Further bioinformatic analysis employing Ingenuity Pathway Analysis revealed significant enrichment in BMS-833923-treated cells for a number of functional categories and networks involved in connective and skeletal tissue development and disorders, e.g., NFκB and STAT signaling. Conclusions. We identified SMO/Hedgehog antagonist (BMS-833923) as a powerful inhibitor of osteoblastic differentiation of hMSC that may be useful as a therapeutic option for treating conditions associated with high heterotopic bone formation and mineralization.

ONO-1301 Enhances in vitro Osteoblast Differentiation and in vivo Bone Formation Induced by Bone Morphogenetic Protein

Spine ◽  
2018 ◽  
Vol 43 (11) ◽  
pp. E616-E624 ◽  
Author(s):  
Sadaaki Kanayama ◽  
Takashi Kaito ◽  
Kazuma Kitaguchi ◽  
Hiroyuki Ishiguro ◽  
Kunihiko Hashimoto ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Morphogenetic Protein ◽  
Osteoblast Differentiation ◽  
Morphogenetic Protein ◽  
In Vivo Bone Formation

scholarly journals Zfp521 antagonizes Runx2, delays osteoblast differentiation in vitro, and promotes bone formation in vivo

Bone ◽  
2009 ◽  
Vol 44 (4) ◽  
pp. 528-536 ◽  
Author(s):  
Meilin Wu ◽  
Eric Hesse ◽  
Frederic Morvan ◽  
Jian-Ping Zhang ◽  
Diego Correa ◽  
...  
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation

scholarly journals Porcine Collagen–Bone Composite Induced Osteoblast Differentiation and Bone Regeneration In Vitro and In Vivo

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 93 ◽  
Author(s):  
Eisner Salamanca ◽  
Chia Chen Hsu ◽  
Wan Ling Yao ◽  
Cheuk Sing Choy ◽  
Yu Hwa Pan ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Regeneration ◽  
Osteoblast Differentiation ◽  
Critical Size ◽  
Guided Bone Regeneration ◽  
Autogenous Bone ◽  
Critical Size Defects ◽  
Bone Formation Markers

Due to autogenous bone limitations, some substitute bone grafts were developed. Collagenated porcine graft (CPG) is able to regenerate new bone, although the number of studies is insufficient, highlighting the need for future studies to better understand the biomaterial. In order to understand better CPG′s possible dental guided bone regeneration indications, the aim of this work was to determine CPG′s biological capacity to induce osteoblast differentiation in vitro and guided bone regeneration in vivo, whilst being compared with commercial hydroxyapatite and beta tricalcium phosphate (HA/β-TCP) and porcine graft alone. Cell cytotoxicity (WST-1), alkaline phosphatase activity (ALP), and real-time polymerase chain reaction (qPCR) were assessed in vitro. Critical size defects of New Zealand white rabbits were used for the in vivo part, with critical size defect closures and histological analyses. WST-1 and ALP indicated that CPG directly stimulated a greater proliferation and confluency of cells with osteoblastic differentiation in vitro. Gene sequencing indicated stable bone formation markers, decreased resorption makers, and bone remodeling coupling factors, making the transition from osteoclast to osteoblast expression at the end of seven days. CPG resulted in the highest new bone regeneration by osteoconduction in critical size defects of rabbit calvaria at eight weeks. Nonetheless, all biomaterials achieved nearly complete calvaria defect closure. CPG was found to be osteoconductive, like porcine graft and HA/β-TCP, but with higher new bone formation in critical size defects of rabbit calvaria at eight weeks. CPG can be used for different dental guided bone regeneration procedures; however, further studies are necessary.

scholarly journals ER stress arm XBP1s plays a pivotal role in proteasome inhibition-induced bone formation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Dan Zhang ◽  
Kim De Veirman ◽  
Rong Fan ◽  
Qiang Jian ◽  
Yuchen Zhang ◽  
...  
Keyword(s):  
Bone Formation ◽  
Er Stress ◽  
Osteogenic Differentiation ◽  
Osteoblast Differentiation ◽  
Bone Destruction ◽  
Proteasome Inhibition ◽  
Stress Signaling ◽  
Alizarin Red

Abstract Background Bone destruction is a hallmark of multiple myeloma (MM). It has been reported that proteasome inhibitors (PIs) can reduce bone resorption and increase bone formation in MM patients, but the underlying mechanisms remain unclear. Methods Mesenchymal stem cells (MSCs) were treated with various doses of PIs, and the effects of bortezomib or carfilzomib on endoplasmic reticulum (ER) stress signaling pathways were analyzed by western blotting and real-time PCR. Alizarin red S (ARS) and alkaline phosphatase (ALP) staining were used to determine the osteogenic differentiation in vitro. Specific inhibitors targeting different ER stress signaling and a Tet-on inducible overexpressing system were used to validate the roles of key ER stress components in regulating osteogenic differentiation of MSCs. Chromatin immunoprecipitation (ChIP) assay was used to evaluate transcription factor-promoter interaction. MicroCT was applied to measure the microarchitecture of bone in model mice in vivo. Results We found that both PERK-ATF4 and IRE1α-XBP1s ER stress branches are activated during PI-induced osteogenic differentiation. Inhibition of ATF4 or XBP1s signaling can significantly impair PI-induced osteogenic differentiation. Furthermore, we demonstrated that XBP1s can transcriptionally upregulate ATF4 expression and overexpressing XBP1s can induce the expression of ATF4 and other osteogenic differentiation-related genes and therefore drive osteoblast differentiation. MicroCT analysis further demonstrated that inhibition of XBP1s can strikingly abolish bortezomib-induced bone formation in mouse. Conclusions These results demonstrated that XBP1s is a master regulator of PI-induced osteoblast differentiation. Activation of IRE1α-XBP1s ER stress signaling can promote osteogenesis, thus providing a novel strategy for the treatment of myeloma bone disease.

Targeted disruption of nuclear factor erythroid-derived 2-like 1 in osteoblasts reduces bone size and bone formation in mice

2010 ◽  
Vol 40 (2) ◽  
pp. 100-110 ◽  
Author(s):  
Jonghyun Kim ◽  
Weirong Xing ◽  
Jon Wergedal ◽  
Jefferson Y. Chan ◽  
Subburaman Mohan
Keyword(s):  
Ascorbic Acid ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Quantitative Computed Tomography ◽  
Antioxidant Response ◽  
Peripheral Quantitative Computed Tomography ◽  
Bone Size ◽  
Nuclear Factor

Previous in vitro studies found that nuclear factor erythroid-derived 2-like 1 (NFE2L1) was involved in mediating ascorbic acid-induced osterix expression and osteoblast differentiation via binding to the antioxidant response element of the osterix promoter. To test the role of NFE2L1 in regulating bone formation in vivo, we disrupted NFE2L1 specifically in osteoblasts. Mice expressing Cre under the control of Col1α2 promoter were crossed with NFE2L1 loxP mice to generate Cre+ knockout (KO) and Cre− wild-type (WT) mice. Skeletal measurements by DEXA revealed 8–10% and 9–11% reduction in total body BMC and bone area in the KO mice from 3 to 8 wk of age. Peripheral quantitative computed tomography analyses found both periosteal and endosteal circumferences were reduced by 6% at the middiaphysis of the femurs from 8 wk old KO mice. Histomorphometric analyses revealed reduced bone formation was a cause for reduced bone size in the KO mice. Microcomputed tomography analysis of the metaphysis of the femur revealed that trabecular bone volume/total volume, and trabecular numbers were decreased by 30 and 53% in the NFE2L1 KO mice. Expression of osterix was decreased by 57% in the bones of NFE2L1 KO mice. In vitro nodule assay demonstrated that mineralized nodule area was reduced by 68% in the cultures of bone marrow stromal cells from NFE2L1 KO mice. Treatment of primary osteoblasts with ascorbic acid increased osterix expression by fourfold, whereas loss of NFE2L1 in osteoblasts diminished ascorbic acid stimulation of osterix expression by 50%. Our data provide the first in vivo experimental evidence that NFE2L1 produced by osteoblasts is involved in regulating osterix expression, osteoblast differentiation, and bone formation.

scholarly journals CLPTM1L induces estrogen receptor β signaling-mediated radioresistance in non-small cell lung cancer cells

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Hang Li ◽  
Jun Che ◽  
Mian Jiang ◽  
Ming Cui ◽  
Guoxing Feng ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Estrogen Receptor ◽  
Small Cell Lung Cancer ◽  
Cell Lung Cancer ◽  
Target Genes ◽  
Small Cell ◽  
Small Cell Lung

Abstract Introduction Radioresistance is a major challenge in lung cancer radiotherapy, and new radiosensitizers are urgently needed. Estrogen receptor β (ERβ) is involved in the progression of non-small cell lung cancer (NSCLC), however, the role of ERβ in the response to radiotherapy in lung cancer remains elusive. In the present study, we investigated the mechanism underlying ERβ-mediated transcriptional activation and radioresistance of NSCLC cells. Methods Quantitative real-time PCR, western blot and immunohistochemistry were used to detect the expression of CLPTM1L, ERβ and other target genes. The mechanism of CLPTM1L in modulation of radiosensitivity was investigated by chromatin immunoprecipitation assay, luciferase reporter gene assay, immunofluorescence staining, confocal microscopy, coimmunoprecipitation and GST pull-down assays. The functional role of CLPTM1L was detected by function assays in vitro and in vivo. Results CLPTM1L expression was negatively correlated with the radiosensitivity of NSCLC cell lines, and irradiation upregulated CLPTM1L in radioresistant (A549) but not in radiosensitive (H460) NSCLC cells. Meanwhile, IR induced the translocation of CLPTM1L from the cytoplasm into the nucleus in NSCLC cells. Moreover, CLPTM1L induced radioresistance in NSCLC cells. iTRAQ-based analysis and cDNA microarray identified irradiation-related genes commonly targeted by CLPTM1L and ERβ, and CLPTM1L upregulated ERβ-induced genes CDC25A, c-Jun, and BCL2. Mechanistically, CLPTM1L coactivated ERβ by directly interacting with ERβ through the LXXLL NR (nuclear receptor)-binding motif. Functionally, ERβ silencing was sufficient to block CLPTM1L-enhanced radioresistance of NSCLC cells in vitro. CLPTM1L shRNA treatment in combination with irradiation significantly inhibited cancer cell growth in NSCLC xenograft tumors in vivo. Conclusions The present results indicate that CLPTM1L acts as a critical coactivator of ERβ to promote the transcription of its target genes and induce radioresistance of NSCLC cells, suggesting a new target for radiosensitization in NSCLC therapy.

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