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Li M, Wang X, Guo M, Zhang W, Li T, Zheng J. Identification of potential cell death-related biomarkers for diagnosis and treatment of osteoporosis. BMC Musculoskelet Disord 2024; 25:235. [PMID: 38528539 DOI: 10.1186/s12891-024-07349-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 03/11/2024] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND This study aimed to identify potential biomarkers for the diagnosis and treatment of osteoporosis (OP). METHODS Data sets were downloaded from the Gene Expression Omnibus database, and differentially programmed cell death-related genes were screened. Functional analyses were performed to predict the biological processes associated with these genes. Least absolute shrinkage and selection operator (LASSO), support vector machine (SVM), and random forest (RF) machine learning algorithms were used to screen for characteristic genes, and receiver operating characteristics were used to evaluate the diagnosis of disease characteristic gene values. Gene set enrichment analysis (GSEA) and single-sample GSEA were conducted to analyze the correlation between characteristic genes and immune infiltrates. Cytoscape and the Drug Gene Interaction Database (DGIdb) were used to construct the mitochondrial RNA-mRNA-transcription factor network and explore small-molecule drugs. Reverse transcription real-time quantitative PCR (RT-qPCR) analysis was performed to evaluate the expression of biomarker genes in clinical samples. RESULTS In total, 25 differential cell death genes were identified. Among these, two genes were screened using the LASSO, SVM, and RF algorithms as characteristic genes, including BRSK2 and VPS35. In GSE56815, the area under the receiver operating characteristic curve of BRSK2 was 0.761 and that of VPS35 was 0.789. In addition, immune cell infiltration analysis showed that BRSK2 positively correlated with CD56dim natural killer cells and negatively correlated with central memory CD4 + T cells. Based on the data from DGIdb, hesperadin was associated with BRSK2, and melagatran was associated with VPS35. BRSK2 and VPS35 were expectably upregulated in OP group compared with controls (all p < 0.05). CONCLUSIONS BRSK2 and VPS35 may be important diagnostic biomarkers of OP.
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Affiliation(s)
- Mingliang Li
- Department of Joint and Sports Medicine, Weifang Sunshine Union Hospital, Weifang, Shandong Province, 261000, China
| | - Xue Wang
- Department of endocrinology, Weifang Sunshine Union Hospital, Weifang, Shandong Province, 261000, China
| | - Mingbo Guo
- Department of Joint and Sports Medicine, Weifang Sunshine Union Hospital, Weifang, Shandong Province, 261000, China
| | - Wenlong Zhang
- Department of Joint and Sports Medicine, Weifang Sunshine Union Hospital, Weifang, Shandong Province, 261000, China
| | - Taotao Li
- Department of Joint and Sports Medicine, Weifang Sunshine Union Hospital, Weifang, Shandong Province, 261000, China
| | - Jinyang Zheng
- Department of spine 1, Weifang Sunshine Union Hospital, No. 9000, Yingqian Street, High-tech Zone, Weifang, Shandong Province, 261000, China.
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Kielbassa K, Van der Weele L, Voskuyl AE, de Vries N, Eldering E, Kuijpers TW. Differential expression pattern of Bcl-2 family members in B and T cells in systemic lupus erythematosus and rheumatoid arthritis. Arthritis Res Ther 2023; 25:225. [PMID: 37993903 PMCID: PMC10664305 DOI: 10.1186/s13075-023-03203-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 10/31/2023] [Indexed: 11/24/2023] Open
Abstract
OBJECTIVE This study aimed to evaluate the expression level of anti-apoptotic Bcl-2 family proteins in B and T cells in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in relation to disease activity and the effect of various Bcl-2 family inhibitors (BH3 mimetics) as potential treatment. METHODS We included 14 SLE patients, 12 RA patients, and 13 healthy controls to study anti-apoptotic Bcl-2, Bcl-XL, and Mcl-1 expression and cell survival in different B and T cell subsets using stimulation assays and intracellular flow cytometry. Effect of various BH3 mimetics was assessed by cell viability analyses. RESULTS In SLE, significant differences in Bcl-2 family members were confined to the B cell compartment with decreased induction of Bcl-XL (p ≤ 0.05) and Mcl-1 (p ≤ 0.001) upon CpG stimulation. In RA, we did not observe any differences in expression levels of Bcl-2 family proteins. Expression patterns did not correlate with disease activity apart from decreased induction of Mcl-1 in B cells in active SLE. After in vitro stimulation with CpG, plasmablasts were more viable after treatment with three different BH3 mimetics compared to naïve or memory B cells in control and patient cells. After activation, Mcl-1 inhibition was most effective in reducing plasmablast and T cell viability, however, less in patients than controls. CONCLUSION Our study provides evidence for the increased differential expression pattern of Bcl-2 family members in B and T cell subsets of patients with SLE compared to controls. Tested BH3 mimetics showed higher efficacy in controls compared to both autoimmune diseases, though nonsignificant due to low patient numbers.
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Affiliation(s)
- K Kielbassa
- Department of Experimental Immunology, Amsterdam Infection & Immunity Institute (AIII), Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Hematology, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Lymphoma and Myeloma Center Amsterdam, Amsterdam, The Netherlands
| | - L Van der Weele
- Department of Experimental Immunology, Amsterdam Infection & Immunity Institute (AIII), Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Centre (ARC), Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
| | - A E Voskuyl
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Centre (ARC), Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands
| | - N de Vries
- Department of Experimental Immunology, Amsterdam Infection & Immunity Institute (AIII), Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Centre (ARC), Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - E Eldering
- Department of Experimental Immunology, Amsterdam Infection & Immunity Institute (AIII), Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Lymphoma and Myeloma Center Amsterdam, Amsterdam, The Netherlands
| | - T W Kuijpers
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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Xu X, Shobuike T, Shiraki M, Kamohara A, Hirata H, Murayama M, Mawatari D, Ueno M, Morimoto T, Kukita T, Mawatari M, Kukita A. Leukemia/lymphoma-related factor (LRF) or osteoclast zinc finger protein (OCZF) overexpression promotes osteoclast survival by increasing Bcl-xl mRNA: A novel regulatory mechanism mediated by the RNA binding protein SAM68. J Transl Med 2022; 102:1000-1010. [PMID: 36775415 DOI: 10.1038/s41374-022-00792-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 11/08/2022] Open
Abstract
RANKL induces NFATc1, a key transcriptional factor to induce osteoclast-specific genes such as cathepsin K, whereas transcriptional control of osteoclast survival is not fully understood. Leukemia/lymphoma-related factor (LRF) in mouse and osteoclast zinc finger protein (OCZF) in rat are zinc finger and BTB domain-containing protein (zBTB) family of transcriptional regulators, and are critical regulators of hematopoiesis. We have previously shown that differentiation and survival were enhanced in osteoclasts from OCZF-Transgenic (Tg) mice. In the present study, we show a possible mechanism of osteoclast survival regulated by LRF/OCZF and the role of OCZF overexpression in pathological bone loss. In the in vitro cultures, LRF was highly colocalized with NFATc1 in cells of early stage in osteoclastogenesis, but only LRF expression persisted after differentiation into mature osteoclasts. LRF expression was further enhanced in resorbing osteoclasts formed on dentin slices. Osteoclast survival inhibitor such as alendronate, a bisphosphonate reduced LRF expression. Micro CT evaluation revealed that femurs of OCZF-Tg mice showed significantly lower bone volume compared to that of WT mice. Furthermore, OCZF overexpression markedly promoted bone loss in ovariectomy-induced osteolytic mouse model. The expression of anti-apoptotic Bcl-xl mRNA, which is formed by alternative splicing, was enhanced in the cultures in which osteoclasts are formed from OCZF-Tg mice. In contrast, the expression of pro-apoptotic Bcl-xs mRNA was lost in the culture derived from OCZF-Tg mice. We found that the expression levels of RNA binding splicing regulator, Src substrate associated in mitosis of 68 kDa (Sam68) protein were markedly decreased in OCZF-Tg mice-derived osteoclasts. In addition, shRNA-mediated knockdown of Sam68 expression increased the expression of Bcl-xl mRNA, suggesting that SAM68 regulates the expression of Bcl-xl. These results indicate that OCZF overexpression reduces protein levels of Sam68, thereby promotes osteoclast survival, and suggest that LRF/OCZF is a promising target for regulating pathological bone loss.
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Affiliation(s)
- Xianghe Xu
- Department of Pathology and Microbiology, Faculty of Medicine, Saga University, Saga, Japan
- Department of Molecular Cell Biology & Oral Anatomy, Faculty of Dentistry, Kyushu University, Fukuoka, Japan
- Department of Orthopaedics, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, 519000, Guangdong, China
| | - Takeo Shobuike
- Department of Pathology and Microbiology, Faculty of Medicine, Saga University, Saga, Japan
| | - Makoto Shiraki
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Asana Kamohara
- Department of Oral & Maxillofacial Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Hirohito Hirata
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masatoshi Murayama
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Daisuke Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaya Ueno
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Tadatsugu Morimoto
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Toshio Kukita
- Department of Molecular Cell Biology & Oral Anatomy, Faculty of Dentistry, Kyushu University, Fukuoka, Japan
| | - Masaaki Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Akiko Kukita
- Department of Pathology and Microbiology, Faculty of Medicine, Saga University, Saga, Japan.
- Research Center of Arthroplasty, Faculty of Medicine, Saga University, Saga, Japan.
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Nishikawa K, Ishii M. Novel method for gain-of-function analyses in primary osteoclasts using a non-viral gene delivery system. J Bone Miner Metab 2021; 39:353-359. [PMID: 33106978 DOI: 10.1007/s00774-020-01161-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/21/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Overexpression studies have been commonly used to yield significant advances in cell biology. In vitro osteoclast culturing involves the differentiation of bone marrow-derived monocyte macrophage precursors (BMMs) in medium supplemented with macrophage colony-stimulating factor and receptor activator of nuclear factor-kB ligand (RANKL) into mature osteoclasts. Retroviral vectors are the gold standards for efficient gene delivery into BMMs. While this strategy is effective in BMMs that are in the early stages of differentiation, it is ineffective in RANKL-treated BMMs such as mono- and multinucleated osteoclasts. This study attempted to enhance gene delivery into differentiated BMMs using liposome-mediated RNA transfection. MATERIAL AND METHODS BMMs were transfected with an EYFP overexpression plasmid or EYFP RNA by lipofection, or transduced with a retroviral vector expressing EYFP. EYFP expression was assessed by flow cytometry. RESULTS We performed overexpression analyses using enhanced yellow fluorescent protein (EYFP). Although EYFP expression was observed 24 h after infection of BMMs with a recombinant retrovirus containing EYFP, expression of EYFP was observed within 3 h of transfection with EYFP RNA. Moreover, the efficiency of EYFP RNA for gene delivery into BMMs was comparable to that of retroviral transduction of EYFP. In contrast, while very few BMMs stimulated by RANKL for two days expressed EYFP after retroviral infection, more than half of the cells expressed EYFP after transfection with EYFP RNA. CONCLUSION RNA-mediated gene delivery is quick and easy method for performing gain-of-function analyses in primary osteoclast precursors and mature osteoclasts.
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Affiliation(s)
- Keizo Nishikawa
- Laboratory of Cell Biology and Metabolic Biochemistry, Department of Medical Life Systems, Graduate School of Life and Medical Sciences, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe, Kyoto, 610-0394, Japan.
- Department of Immunology and Cell Biology, Graduate School of Medicine/Frontier Biosciences, Osaka University, Yamada-oka 2-2, Suita, Osaka, 565-0871, Japan.
- WPI-Immunology Frontier Research Center, Osaka University, Yamada-oka 2-2, Suita, Osaka, 565-0871, Japan.
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine/Frontier Biosciences, Osaka University, Yamada-oka 2-2, Suita, Osaka, 565-0871, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Yamada-oka 2-2, Suita, Osaka, 565-0871, Japan
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Xu Z, Zhu X, Wang M, Lu Y, Dai C. FGF/FGFR2 Protects against Tubular Cell Death and Acute Kidney Injury Involving Erk1/2 Signaling Activation. KIDNEY DISEASES 2020; 6:181-194. [PMID: 32523960 DOI: 10.1159/000505661] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/31/2019] [Indexed: 12/11/2022]
Abstract
Background Fibroblast growth factors (FGFs) are heparin-binding proteins involved in a variety of biological processes, and part of them may act through binding with cell membrane receptor FGFR2. Objectives To clarify the role and mechanisms of FGFR2 signaling in tubular cell survival and acute kidney injury (AKI). Method In this study, kidney ischemia/reperfusion (IR) or cisplatin injection was used to induce AKI in mice. Results In the kidneys after IR or cisplatin injection, the expression of FGFs and Erk1/2 phosphorylation were elevated. To investigate the role of FGFs in tubular cell survival and AKI, a mouse model with tubular cell specific FGFR2 gene disruption was generated. The knockouts were born normal. At 2 months of age, about one-third of the knockouts developed mild hydronephrosis. Ablation of FGFR2 in tubular cells aggravated acute kidney dysfunction as well as tubular cell apoptosis induced by IR or cisplatin. In addition, Erk1/2 phosphorylation was less in the knockout kidneys than in control littermates at day 1 after cisplatin injection. In cultured NRK-52E cells, recombinant FGF2 protein induced Erk1/2 phosphorylation and inhibited cisplatin-induced cell death. PD98059 abolished Erk1/2 phosphorylation and partly reversed the protective effect of FGF2 on cisplatin-induced cell death. Conclusions This study indicates that FGF/FGFR2 signaling plays an important role in protecting against tubular cell death and AKI, which is partly through stimulating Erk1/2 activation.
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Affiliation(s)
- Zhuo Xu
- Center for Kidney Disease, the Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Xingwen Zhu
- Endocrine Department, the Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Mingjie Wang
- Center for Kidney Disease, the Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Yibing Lu
- Endocrine Department, the Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Chunsun Dai
- Center for Kidney Disease, the Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
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Shang N, Wu J. Egg White Ovotransferrin Attenuates RANKL-Induced Osteoclastogenesis and Bone Resorption. Nutrients 2019; 11:nu11092254. [PMID: 31546863 PMCID: PMC6770797 DOI: 10.3390/nu11092254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/17/2019] [Accepted: 09/17/2019] [Indexed: 01/13/2023] Open
Abstract
Ovotransferrin, a member of the transferrin family, is the second main protein found in egg white. Ovotransferrin was reported to have antimicrobial, antioxidant, and immunomodulating activities. The aim of this work was to characterize the cellular and molecular functions of egg white ovotransferrin on osteoclasts differentiation and function. Osteoclasts were prepared from mouse macrophage RAW 264.7 cells stimulated with receptor activator of nuclear factor κB ligand (RANKL). Ovotransferrin inhibited osteoclasts differentiation and the calcium–phosphate resorptive ability via the suppression of RANKL-induced nuclear factor κ-light chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Ovotransferrin induced apoptosis of matured osteoclasts, accompanied by increased expression of Bcl-2-like protein 11 (Bim) and Bcl-2-assoicated death promoter (Bad), but decreased expression of B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra-large (Bcl-xl). We established a novel role of egg white ovotransferrin as an inhibitor of osteoclastogenesis, which may be used for the prevention of osteoporosis.
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Affiliation(s)
- Nan Shang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
| | - Jianping Wu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
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Abstract
PURPOSE Transgenic Cre lines are a valuable tool for conditionally inactivating or activating genes to understand their function. Here, we provide an overview of Cre transgenic models used for studying gene function in bone cells and discuss their advantages and limitations, with particular emphasis on Cre lines used for studying osteocyte and osteoclast function. RECENT FINDINGS Recent studies have shown that many bone cell-targeted Cre models are not as specific as originally thought. To ensure accurate data interpretation, it is important for investigators to test for unexpected recombination events due to transient expression of Cre recombinase during development or in precursor cells and to be aware of the potential for germ line recombination of targeted genes as well as the potential for unexpected phenotypes due to the Cre transgene. Although many of the bone-targeted Cre-deleter strains are imperfect and each model has its own limitations, their careful use will continue to provide key advances in our understanding of bone cell function in health and disease.
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Affiliation(s)
- Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA.
| | - Yixia Xie
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA
| | - Lora A Shiflett
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA
| | - Yasuyoshi Ueki
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA
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Liao MH, Lin PI, Ho WP, Chan WP, Chen TL, Chen RM. Participation of GATA-3 in regulation of bone healing through transcriptional upregulation of bcl-x L expression. Exp Mol Med 2017; 49:e398. [PMID: 29170477 PMCID: PMC5704189 DOI: 10.1038/emm.2017.182] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 04/17/2017] [Accepted: 05/08/2017] [Indexed: 02/06/2023] Open
Abstract
We have previously demonstrated the expression of GATA-DNA-binding protein (GATA)-3, a transcription factor, in osteoblasts and have verified its function in transducing cell survival signaling. This translational study was further designed to evaluate the roles of GATA-3 in regulating bone healing and to explore its possible mechanisms. A metaphyseal bone defect was created in the left femurs of male ICR mice. Analysis by micro-computed topography showed that the bone volume, trabecular bone number and trabecular thickness were augmented and that the trabecular pattern factor decreased. Interestingly, immunohistological analyses showed specific expression of GATA-3 in the defect area. In addition, colocalized expression of GATA-3 and alkaline phosphatase was observed at the wound site. As the fracture healed, the amounts of phosphorylated and non-phosphorylated GATA-3 concurrently increased. Separately, GATA-3 mRNA was induced during bone healing, and, levels of Runx2 mRNA and protein were also increased. The results of confocal microscopy and co-immunoprecipitation showed an association between nuclear GATA-3 and Runx2 in the area of insult. In parallel with fracture healing, Bcl-XL mRNA was significantly triggered. A bioinformatic search revealed the existence of a GATA-3-specific DNA-binding element in the promoter region of the bcl-xL gene. Analysis by chromatin immunoprecipitation assays further demonstrated transactivation activity by which GATA-3 regulated bcl-xL gene expression. Therefore, this study shows that GATA-3 participates in the healing of bone fractures via regulating bcl-xL gene expression, owing to its association with Runx2. In the clinic, GATA-3 may be used as a biomarker for diagnoses/prognoses or as a therapeutic target for bone diseases, such as bone fractures.
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Affiliation(s)
- Mei-Hsiu Liao
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Pei-I Lin
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wei-Pin Ho
- Cell Physiology and Molecular Image Research Center, Taipei Medical University-Wan Fang Medical Center, Taipei, Taiwan
- Department of Orthopedic Surgery, Taipei Medical University-Wan Fang Medical Center, Taipei, Taiwan
| | - Wing P Chan
- Cell Physiology and Molecular Image Research Center, Taipei Medical University-Wan Fang Medical Center, Taipei, Taiwan
- Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Ta-Liang Chen
- Anesthesiology and Health Policy Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Ruei-Ming Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Cell Physiology and Molecular Image Research Center, Taipei Medical University-Wan Fang Medical Center, Taipei, Taiwan
- Anesthesiology and Health Policy Research Center, Taipei Medical University Hospital, Taipei, Taiwan
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Hirozane T, Tohmonda T, Yoda M, Shimoda M, Kanai Y, Matsumoto M, Morioka H, Nakamura M, Horiuchi K. Conditional abrogation of Atm in osteoclasts extends osteoclast lifespan and results in reduced bone mass. Sci Rep 2016; 6:34426. [PMID: 27677594 PMCID: PMC5039636 DOI: 10.1038/srep34426] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 09/13/2016] [Indexed: 01/06/2023] Open
Abstract
Ataxia-telangiectasia mutated (ATM) kinase is a central component involved in the signal transduction of the DNA damage response (DDR) and thus plays a critical role in the maintenance of genomic integrity. Although the primary functions of ATM are associated with the DDR, emerging data suggest that ATM has many additional roles that are not directly related to the DDR, including the regulation of oxidative stress signaling, insulin sensitivity, mitochondrial homeostasis, and lymphocyte development. Patients and mice lacking ATM exhibit growth retardation and lower bone mass; however, the mechanisms underlying the skeletal defects are not fully understood. In the present study, we generated mutant mice in which ATM is specifically inactivated in osteoclasts. The mutant mice did not exhibit apparent developmental defects but showed reduced bone mass due to increased osteoclastic bone resorption. Osteoclasts lacking ATM were more resistant to apoptosis and showed a prolonged lifespan compared to the controls. Notably, the inactivation of ATM in osteoclasts resulted in enhanced NF-κB signaling and an increase in the expression of NF-κB-targeted genes. The present study reveals a novel function for ATM in regulating bone metabolism by suppressing the lifespan of osteoclasts and osteoclast-mediated bone resorption.
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Affiliation(s)
- Toru Hirozane
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
- Japan Society for the Promotion of Science, Tokyo 102-8472, Japan
| | - Takahide Tohmonda
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
- Department of Anti-Aging Orthopedic Research, Keio University School of Medicine, Tokyo, Japan
| | - Masaki Yoda
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
- Department of Anti-Aging Orthopedic Research, Keio University School of Medicine, Tokyo, Japan
| | - Masayuki Shimoda
- Department of Pathology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Yae Kanai
- Department of Pathology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Morio Matsumoto
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Hideo Morioka
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Masaya Nakamura
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Keisuke Horiuchi
- Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
- Department of Anti-Aging Orthopedic Research, Keio University School of Medicine, Tokyo, Japan
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Tan P, Guan H, Xie L, Mi B, Fang Z, Li J, Li F. FOXO1 inhibits osteoclastogenesis partially by antagnozing MYC. Sci Rep 2015; 5:16835. [PMID: 26568463 PMCID: PMC4645183 DOI: 10.1038/srep16835] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/21/2015] [Indexed: 12/19/2022] Open
Abstract
FOXO transcription factors especially FOXO1 have profound roles in bone development and remodeling. The regulation of cells of the osteoblast lineage by FOXOs is suggested to be stage-specific or context dependent. Intriguingly, recent studies on the role played by FOXOs in osteoclastogenesis reached different conclusion. Bartell et al. showed that FOXOs restrained osteoclastogenesis and bone resorption partially by upregulation of the H2O2-inactivating enzyme catalase. Wang et al. demonstrated that FOXO1 activated osteoclast formation. In the present study, we confirmed the results of Bartell et al. that FOXO1 expression was reduced upon stimulation of RANKL; FOXO1 inhibition promoted and FOXO1 activation repressed, osteoclast differentiation and activity; the inhibitory effect of FOXO1 on osteoclastogenesis was partially mediated by ROS since treatment with ROS scavengers cancelled the effect of FOXO1 inhibition on osteoclastogenesis. We further investigated the mechanisms responsible for repressed osteoclastogenesis by FOXO1. We found that FOXO1 inhibition modulated MAPKs, NF-κB and AP-1. Finally, we proved that the inhibitory effect of FOXO1 on osteoclast formation was partially mediated by MYC suppression by showing that MYC repression almost totally abrogated the effect of FOXO1 inhibition on osteoclastogenesis. To conclude, our study confirmed FOXO1 as a cell-autonomous inhibitor of osteoclastogenesis.
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Affiliation(s)
- Peng Tan
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hanfeng Guan
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Linka Xie
- Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Baoguo Mi
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhong Fang
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jing Li
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Feng Li
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Sochalska M, Tuzlak S, Egle A, Villunger A. Lessons from gain- and loss-of-function models of pro-survival Bcl2 family proteins: implications for targeted therapy. FEBS J 2015; 282:834-849. [PMID: 25559680 PMCID: PMC4562365 DOI: 10.1111/febs.13188] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/22/2014] [Accepted: 01/02/2015] [Indexed: 01/23/2023]
Abstract
Cell survival depends on the maintenance of mitochondrial integrity controlled by a well-balanced interplay between anti- and pro-apoptotic B cell lymphoma 2 (Bcl2) family members. Given their frequent deregulation in human pathologies, including autoimmunity and cancer, significant research efforts have increased our molecular understanding of how Bcl2 proteins control cell death. This has fostered the development of small non-peptidic compounds, so-called BH3-mimetics, that show excellent prospects of passing clinical trials and entering daily use for targeted therapy. Possible limitations in clinical application may, to a certain degree, be predicted from loss-of-function phenotypes gathered from studies using gene-modified mice that we attempt to summarize and discuss in this context.
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Affiliation(s)
- Maja Sochalska
- Division of Developmental Immunology, Biocenter, Medical University Innsbruck, Austria
| | - Selma Tuzlak
- Division of Developmental Immunology, Biocenter, Medical University Innsbruck, Austria
| | - Alexander Egle
- Laboratory for Immunological and Molecular Cancer Research, Third Medical Department, Paracelsus Medical University, Salzburg, Austria
| | - Andreas Villunger
- Division of Developmental Immunology, Biocenter, Medical University Innsbruck, Austria
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12
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Wang H, Misaki T, Taupin V, Eguchi A, Ghosh P, Farquhar MG. GIV/girdin links vascular endothelial growth factor signaling to Akt survival signaling in podocytes independent of nephrin. J Am Soc Nephrol 2014; 26:314-27. [PMID: 25012178 DOI: 10.1681/asn.2013090985] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Podocytes are critically involved in the maintenance of the glomerular filtration barrier and are key targets of injury in many glomerular diseases. Chronic injury leads to progressive loss of podocytes, glomerulosclerosis, and renal failure. Thus, it is essential to maintain podocyte survival and avoid apoptosis after acute glomerular injury. In normal glomeruli, podocyte survival is mediated via nephrin-dependent Akt signaling. In several glomerular diseases, nephrin expression decreases and podocyte survival correlates with increased vascular endothelial growth factor (VEGF) signaling. How VEGF signaling contributes to podocyte survival and prevents apoptosis remains unknown. We show here that Gα-interacting, vesicle-associated protein (GIV)/girdin mediates VEGF receptor 2 (VEGFR2) signaling and compensates for nephrin loss. In puromycin aminonucleoside nephrosis (PAN), GIV expression increased, GIV was phosphorylated by VEGFR2, and p-GIV bound and activated Gαi3 and enhanced downstream Akt2, mammalian target of rapamycin complex 1 (mTORC1), and mammalian target of rapamycin complex-2 (mTORC2) signaling. In GIV-depleted podocytes, VEGF-induced Akt activation was abolished, apoptosis was triggered, and cell migration was impaired. These effects were reversed by introducing GIV but not a GIV mutant that cannot activate Gαi3. Our data indicate that after PAN injury, VEGF promotes podocyte survival by triggering assembly of an activated VEGFR2/GIV/Gαi3 signaling complex and enhancing downstream PI3K/Akt survival signaling. Because of its important role in promoting podocyte survival, GIV may represent a novel target for therapeutic intervention in the nephrotic syndrome and other proteinuric diseases.
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Affiliation(s)
- Honghui Wang
- Departments of Cellular and Molecular Medicine and
| | - Taro Misaki
- Departments of Cellular and Molecular Medicine and
| | | | - Akiko Eguchi
- Medicine, University of California, San Diego, La Jolla, California
| | - Pradipta Ghosh
- Medicine, University of California, San Diego, La Jolla, California
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13
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Boyce BF. Advances in osteoclast biology reveal potential new drug targets and new roles for osteoclasts. J Bone Miner Res 2013; 28:711-22. [PMID: 23436579 PMCID: PMC3613781 DOI: 10.1002/jbmr.1885] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 01/06/2023]
Abstract
Osteoclasts are multinucleated myeloid lineage cells formed in response to macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL) by fusion of bone marrow-derived precursors that circulate in the blood and are attracted to sites of bone resorption in response to factors, such as sphingosine-1 phosphate signaling. Major advances in understanding of the molecular mechanisms regulating osteoclast functions have been made in the past 20 years, mainly from mouse and human genetic studies. These have revealed that osteoclasts express and respond to proinflammatory and anti-inflammatory cytokines. Some of these cytokines activate NF-κB and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling to induce osteoclast formation and activity and also regulate communication with neighboring cells through signaling proteins, including ephrins and semaphorins. Osteoclasts also positively and negatively regulate immune responses and osteoblastic bone formation. These advances have led to development of new inhibitors of bone resorption that are in clinical use or in clinical trials; and more should follow, based on these advances. This article reviews current understanding of how bone resorption is regulated both positively and negatively in normal and pathologic states.
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Affiliation(s)
- Brendan F Boyce
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
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14
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TAK1 is essential for osteoclast differentiation and is an important modulator of cell death by apoptosis and necroptosis. Mol Cell Biol 2012; 33:582-95. [PMID: 23166301 DOI: 10.1128/mcb.01225-12] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Transforming growth factor β (TGF-β)-activated kinase 1 (TAK1), a mitogen-activated protein 3 (MAP3) kinase, plays an essential role in inflammation by activating the IκB kinase (IKK)/nuclear factor κB (NF-κB) and stress kinase (p38 and c-Jun N-terminal kinase [JNK]) pathways in response to many stimuli. The tumor necrosis factor (TNF) superfamily member receptor activator of NF-κB ligand (RANKL) regulates osteoclastogenesis through its receptor, RANK, and the signaling adaptor TRAF6. Because TAK1 activation is mediated through TRAF6 in the interleukin 1 receptor (IL-1R) and toll-like receptor (TLR) pathways, we sought to investigate the consequence of TAK1 deletion in RANKL-mediated osteoclastogenesis. We generated macrophage colony-stimulating factor (M-CSF)-derived monocytes from the bone marrow of mice with TAK1 deletion in the myeloid lineage. Unexpectedly, TAK1-deficient monocytes in culture died rapidly but could be rescued by retroviral expression of TAK1, inhibition of receptor-interacting protein 1 (RIP1) kinase activity with necrostatin-1, or simultaneous genetic deletion of TNF receptor 1 (TNFR1). Further investigation using TAK1-deficient mouse embryonic fibroblasts revealed that TNF-α-induced cell death was abrogated by the simultaneous inhibition of caspases and knockdown of RIP3, suggesting that TAK1 is an important modulator of both apoptosis and necroptosis. Moreover, TAK1-deficient monocytes rescued from programmed cell death did not form mature osteoclasts in response to RANKL, indicating that TAK1 is indispensable to RANKL-induced osteoclastogenesis. To our knowledge, we are the first to report that mice in which TAK1 has been conditionally deleted in osteoclasts develop osteopetrosis.
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15
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Miyazaki T, Iwasawa M, Nakashima T, Mori S, Shigemoto K, Nakamura H, Katagiri H, Takayanagi H, Tanaka S. Intracellular and extracellular ATP coordinately regulate the inverse correlation between osteoclast survival and bone resorption. J Biol Chem 2012; 287:37808-23. [PMID: 22988253 PMCID: PMC3488055 DOI: 10.1074/jbc.m112.385369] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 09/09/2012] [Indexed: 11/06/2022] Open
Abstract
Osteoclasts, highly differentiated bone-resorbing cells of hematopoietic origin, have two conflicting tendencies: a lower capacity to survive and a higher capacity to execute energy-consuming activities such as bone resorption. Here, we report that when compared with their precursors, mature mitochondria-rich osteoclasts have lower levels of intracellular ATP, which is associated with receptor activator of nuclear factor κ-B ligand (RANKL)-induced Bcl-x(L) down-regulation. Severe ATP depletion, caused by disrupting mitochondrial transcription factor A (Tfam) gene, leads to increased bone-resorbing activity despite accelerated apoptosis. Although AMP-activated protein kinase (AMPK) activation by ATP depletion is not involved in the regulation of osteoclast function, the release of ATP from intracellular stores negatively regulates bone-resorbing activity through an autocrine/paracrine feedback loop by altering cytoskeletal structures. Furthermore, osteoclasts derived from aged mice exhibit reduced mitochondrial DNA (mtDNA) and intracellular ATP levels with increased bone-resorbing activity, implicating the possible involvement of age-related mitochondrial dysfunction in osteoporosis. Thus, our study provides evidence for a mechanism underlying the control of cellular functions by reciprocal changes in intracellular and extracellular ATP, which regulate the negative correlation between osteoclast survival and bone resorption.
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Affiliation(s)
- Tsuyoshi Miyazaki
- Department of Geriatric Medicine, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
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16
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Decuypere JP, Parys JB, Bultynck G. Regulation of the autophagic bcl-2/beclin 1 interaction. Cells 2012; 1:284-312. [PMID: 24710477 PMCID: PMC3901098 DOI: 10.3390/cells1030284] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/06/2012] [Accepted: 06/15/2012] [Indexed: 12/18/2022] Open
Abstract
Autophagy is an intracellular degradation process responsible for the delivery of cellular material to the lysosomes. One of the key mechanisms for control of autophagy is the modulation of the interaction between the autophagic protein Beclin 1 and the members of the anti-apoptotic Bcl-2 family (e.g., Bcl-2, Bcl-XL and Mcl-1). This binding is regulated by a variety of proteins and compounds that are able to enhance or inhibit the Bcl-2/Beclin 1 interaction in order to repress or activate autophagy, respectively. In this review we will focus on this interaction and discuss its characteristics, relevance and regulation.
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Affiliation(s)
- Jean-Paul Decuypere
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, O/N-1, bus 802, Herestraat 49, Leuven, BE-3000, Belgium.
| | - Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, O/N-1, bus 802, Herestraat 49, Leuven, BE-3000, Belgium.
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, O/N-1, bus 802, Herestraat 49, Leuven, BE-3000, Belgium.
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17
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Elefteriou F, Yang X. Genetic mouse models for bone studies--strengths and limitations. Bone 2011; 49:1242-54. [PMID: 21907838 PMCID: PMC3331798 DOI: 10.1016/j.bone.2011.08.021] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/15/2011] [Accepted: 08/18/2011] [Indexed: 11/25/2022]
Abstract
Mice have become a preferred model system for bone research because of their genetic and pathophysiological similarities to humans: a relatively short reproductive period, leading to relatively low cost of maintenance and the availability of the entire mouse genome sequence information. The success in producing the first transgenic mouse line that expressed rabbit β-globin protein in mouse erythrocytes three decades ago marked the beginning of the use of genetically engineered mice as model system to study human diseases. Soon afterward the development of cultured pluripotent embryonic stem cells provided the possibility of gene replacement or gene deletion in mice. These technologies have been critical to identify new genes involved in bone development, growth, remodeling, repair, and diseases, but like many other approaches, they have limitations. This review will introduce the approaches that allow the generation of transgenic mice and global or conditional (tissue-specific and inducible) mutant mice. A list of the various promoters used to achieve bone-specific gene deletion or overexpression is included. The limitations of these approaches are discussed, and general guidelines related to the analysis of genetic mouse models are provided.
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Affiliation(s)
- Florent Elefteriou
- Vanderbilt University Medical Center, Department of Medicine, Vanderbilt Center for Bone Biology, 1235H Light Hall, Nashville, TN 37232-0575, USA
| | - Xiangli Yang
- Vanderbilt University Medical Center, Department of Medicine, Vanderbilt Center for Bone Biology, 1235H Light Hall, Nashville, TN 37232-0575, USA
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18
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Edwards JR, Mundy GR. Advances in osteoclast biology: old findings and new insights from mouse models. Nat Rev Rheumatol 2011; 7:235-43. [PMID: 21386794 DOI: 10.1038/nrrheum.2011.23] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The maintenance of adequate bone mass is dependent upon the controlled and timely removal of old, damaged bone. This complex process is performed by the highly specialized, multinucleated osteoclast. Over the past 15 years, a detailed picture has emerged describing the origins, differentiation pathways and activation stages that contribute to normal osteoclast function. This information has primarily been obtained by the development and skeletal analysis of genetically modified mouse models. Mice harboring mutations in specific genetic loci exhibit bone defects as a direct result of aberrations in normal osteoclast recruitment, formation or function. These findings include the identification of the RANK-RANKL-OPG system as a primary mediator of osteoclastogenesis, the characterization of ion transport and cellular attachment mechanisms and the recognition that matrix-degrading enzymes are essential components of resorptive activity. This Review focuses on the principal observations in osteoclast biology derived from genetic mouse models, and highlights emerging concepts that describe how the osteoclast is thought to contribute to the maintenance of adequate bone mass and integrity throughout life.
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Affiliation(s)
- James R Edwards
- Institute of Musculoskeletal Sciences, University of Oxford, Nuffield Orthopedic Center, Windmill Road, Oxford OX3 7LD, UK.
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19
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Yang C, McCoy K, Davis JL, Schmidt-Supprian M, Sasaki Y, Faccio R, Novack DV. NIK stabilization in osteoclasts results in osteoporosis and enhanced inflammatory osteolysis. PLoS One 2010; 5:e15383. [PMID: 21151480 PMCID: PMC2975662 DOI: 10.1371/journal.pone.0015383] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 08/31/2010] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Maintenance of healthy bone requires the balanced activities of osteoclasts (OCs), which resorb bone, and osteoblasts, which build bone. Disproportionate action of OCs is responsible for the bone loss associated with postmenopausal osteoporosis and rheumatoid arthritis. NF-κB inducing kinase (NIK) controls activation of the alternative NF-κB pathway, a critical pathway for OC differentiation. Under basal conditions, TRAF3-mediated NIK degradation prevents downstream signaling, and disruption of the NIK:TRAF3 interaction stabilizes NIK leading to constitutive activation of the alternative NF-κB pathway. METHODOLOGY/PRINCIPAL FINDINGS Using transgenic mice with OC-lineage expression of NIK lacking its TRAF3 binding domain (NT3), we now find that alternative NF-κB activation enhances not only OC differentiation but also OC function. Activating NT3 with either lysozyme M Cre or cathepsinK Cre causes high turnover osteoporosis with increased activity of OCs and osteoblasts. In vitro, NT3-expressing precursors form OCs more quickly and at lower doses of RANKL. When cultured on bone, they exhibit larger actin rings and increased resorptive activity. OC-specific NT3 transgenic mice also have an exaggerated osteolytic response to the serum transfer model of arthritis. CONCLUSIONS Constitutive activation of NIK drives enhanced osteoclastogenesis and bone resorption, both in basal conditions and in response to inflammatory stimuli.
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Affiliation(s)
- Chang Yang
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kathleen McCoy
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jennifer L. Davis
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | | | | | - Roberta Faccio
- Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Deborah Veis Novack
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri, United States of America
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20
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Miyauchi Y, Ninomiya K, Miyamoto H, Sakamoto A, Iwasaki R, Hoshi H, Miyamoto K, Hao W, Yoshida S, Morioka H, Chiba K, Kato S, Tokuhisa T, Saitou M, Toyama Y, Suda T, Miyamoto T. The Blimp1-Bcl6 axis is critical to regulate osteoclast differentiation and bone homeostasis. ACTA ACUST UNITED AC 2010; 207:751-62. [PMID: 20368579 PMCID: PMC2856022 DOI: 10.1084/jem.20091957] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Controlling osteoclastogenesis is critical to maintain physiological bone homeostasis and prevent skeletal disorders. Although signaling activating nuclear factor of activated T cells 1 (NFATc1), a transcription factor essential for osteoclastogenesis, has been intensively investigated, factors antagonistic to NFATc1 in osteoclasts have not been characterized. Here, we describe a novel pathway that maintains bone homeostasis via two transcriptional repressors, B cell lymphoma 6 (Bcl6) and B lymphocyte–induced maturation protein-1 (Blimp1). We show that Bcl6 directly targets ‘osteoclastic’ molecules such as NFATc1, cathepsin K, and dendritic cell-specific transmembrane protein (DC-STAMP), all of which are targets of NFATc1. Bcl6-overexpression inhibited osteoclastogenesis in vitro, whereas Bcl6-deficient mice showed accelerated osteoclast differentiation and severe osteoporosis. We report that Bcl6 is a direct target of Blimp1 and that mice lacking Blimp1 in osteoclasts exhibit osteopetrosis caused by impaired osteoclastogenesis resulting from Bcl6 up-regulation. Indeed, mice doubly mutant in Blimp1 and Bcl6 in osteoclasts exhibited decreased bone mass with increased osteoclastogenesis relative to osteoclast-specific Blimp1-deficient mice. These results reveal a Blimp1–Bcl6–osteoclastic molecule axis, which critically regulates bone homeostasis by controlling osteoclastogenesis and may provide a molecular basis for novel therapeutic strategies.
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Affiliation(s)
- Yoshiteru Miyauchi
- Department of Orthopedic Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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21
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Diehl F, Brown MA, van Amerongen MJ, Novoyatleva T, Wietelmann A, Harriss J, Ferrazzi F, Böttger T, Harvey RP, Tucker PW, Engel FB. Cardiac deletion of Smyd2 is dispensable for mouse heart development. PLoS One 2010; 5:e9748. [PMID: 20305823 PMCID: PMC2840034 DOI: 10.1371/journal.pone.0009748] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 02/25/2010] [Indexed: 01/02/2023] Open
Abstract
Chromatin modifying enzymes play a critical role in cardiac differentiation. Previously, it has been shown that the targeted deletion of the histone methyltransferase, Smyd1, the founding member of the SET and MYND domain containing (Smyd) family, interferes with cardiomyocyte maturation and proper formation of the right heart ventricle. The highly related paralogue, Smyd2 is a histone 3 lysine 4- and lysine 36-specific methyltransferase expressed in heart and brain. Here, we report that Smyd2 is differentially expressed during cardiac development with highest expression in the neonatal heart. To elucidate the functional role of Smyd2 in the heart, we generated conditional knockout (cKO) mice harboring a cardiomyocyte-specific deletion of Smyd2 and performed histological, functional and molecular analyses. Unexpectedly, cardiac deletion of Smyd2 was dispensable for proper morphological and functional development of the murine heart and had no effect on global histone 3 lysine 4 or 36 methylation. However, we provide evidence for a potential role of Smyd2 in the transcriptional regulation of genes associated with translation and reveal that Smyd2, similar to Smyd3, interacts with RNA Polymerase II as well as to the RNA helicase, HELZ.
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Affiliation(s)
- Florian Diehl
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Hessen, Germany
| | - Mark A. Brown
- Section of Molecular Genetics and Microbiology and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Machteld J. van Amerongen
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Hessen, Germany
| | - Tatyana Novoyatleva
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Hessen, Germany
| | - Astrid Wietelmann
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Hessen, Germany
| | - June Harriss
- Section of Molecular Genetics and Microbiology and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Fulvia Ferrazzi
- Dipartimento di Informatica e Sistemistica, Università degli Studi di Pavia, Pavia, Lombardia, Italia
| | - Thomas Böttger
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Hessen, Germany
| | - Richard P. Harvey
- Developmental Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Philip W. Tucker
- Section of Molecular Genetics and Microbiology and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Felix B. Engel
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Hessen, Germany
- * E-mail:
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