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Knowles HJ, Vasilyeva A, Sheth M, Pattinson O, May J, Rumney RMH, Hulley PA, Richards DB, Carugo D, Evans ND, Stride E. Use of oxygen-loaded nanobubbles to improve tissue oxygenation: Bone-relevant mechanisms of action and effects on osteoclast differentiation. Biomaterials 2024; 305:122448. [PMID: 38218121 DOI: 10.1016/j.biomaterials.2023.122448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/14/2023] [Accepted: 12/21/2023] [Indexed: 01/15/2024]
Abstract
Gas-loaded nanobubbles have potential as a method of oxygen delivery to increase tumour oxygenation and therapeutically alleviate tumour hypoxia. However, the mechanism(s) whereby oxygen-loaded nanobubbles increase tumour oxygenation are unknown; with their calculated oxygen-carrying capacity being insufficient to explain this effect. Intra-tumoural hypoxia is a prime therapeutic target, at least partly due to hypoxia-dependent stimulation of the formation and function of bone-resorbing osteoclasts which establish metastatic cells in bone. This study aims to investigate potential mechanism(s) of oxygen delivery and in particular the possible use of oxygen-loaded nanobubbles in preventing bone metastasis via effects on osteoclasts. Lecithin-based nanobubbles preferentially interacted with phagocytic cells (monocytes, osteoclasts) via a combination of lipid transfer, clathrin-dependent endocytosis and phagocytosis. This interaction caused general suppression of osteoclast differentiation via inhibition of cell fusion. Additionally, repeat exposure to oxygen-loaded nanobubbles inhibited osteoclast formation to a greater extent than nitrogen-loaded nanobubbles. This gas-dependent effect was driven by differential effects on the fusion of mononuclear precursor cells to form pre-osteoclasts, partly due to elevated potentiation of RANKL-induced ROS by nitrogen-loaded nanobubbles. Our findings suggest that oxygen-loaded nanobubbles could represent a promising therapeutic strategy for cancer therapy; reducing osteoclast formation and therefore bone metastasis via preferential interaction with monocytes/macrophages within the tumour and bone microenvironment, in addition to known effects of directly improving tumour oxygenation.
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Affiliation(s)
- Helen J Knowles
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Alexandra Vasilyeva
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK; Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
| | - Mihir Sheth
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK; Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
| | - Oliver Pattinson
- Bone and Joint Research Group, Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Jonathan May
- Bone and Joint Research Group, Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Robin M H Rumney
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, UK
| | - Philippa A Hulley
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Duncan B Richards
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Dario Carugo
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Nicholas D Evans
- Bone and Joint Research Group, Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Eleanor Stride
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK; Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.
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Elhakim A, Kim S, Shin SJ, Jung HS, Kim E. Effect of icariin surface treatment on the resorption of denuded roots after replantation in rat. Int Endod J 2023; 56:1550-1558. [PMID: 37787769 DOI: 10.1111/iej.13980] [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: 06/28/2023] [Revised: 09/12/2023] [Accepted: 09/21/2023] [Indexed: 10/04/2023]
Abstract
AIM Limiting the incidence of resorption associated with delayed replantation of avulsed teeth is critical for long-term tooth survival. In this study, we assessed whether icariin, a natural product with anti-osteoclastic properties, could reduce root resorption in a rat model of tooth replantation. METHODOLOGY Cytocompatibility of icariin (10, 20, 40 and 80 μM) was evaluated by CCK-8 proliferation assay in vitro, and an osteoclastogenesis assay was performed to evaluate the effect of icariin on the differentiation of rat bone marrow macrophages and human peripheral blood monocytes into tartrate-resistant acid phosphatase-stained (TRAP+ ) multinucleated giant cells (MNGCs). Differentiation of human periodontal ligament stem cells (hPDLSCs) treated with icariin (10 μM) was also evaluated at 5, 10 and 21 days of osteogenic induction. The first maxillary molars of five-week-old male Sprague-Dawley rats were extracted, denuded of PDL, then treated either with neutralized collagen solution (Carrier control) or icariin in collagen (3 μg/μL) before replantation into their sockets. The animals were euthanized 2 weeks post-surgery for micro-computed tomography (micro-CT) imaging and histological analyses. RESULTS Icariin was cytocompatible and significantly reduced the differentiation of TRAP+ MNGCs in a dose-dependent manner compared to the control. Moreover, icariin enhanced alkaline phosphatase activity, expression of osteogenic marker genes and proteins, and calcium deposition in hPDLSCs. Micro-CT imaging of the replanted samples demonstrated a significantly higher volume of remaining roots in the icariin-treated group than in the control group. Histological analysis revealed a marked number of resorptive lacunae with TRAP activity in the control group, whereas icariin-treated samples showed signs of functional healing and reduced osteoclastic activity. CONCLUSIONS Icariin was biocompatible and demonstrated potent anti-osteoclastic and pro-osteogenic properties that reduced resorption and promoted functional healing of denuded roots in a rat maxillary first molar model of replantation. These findings indicate that root surface treatment with icariin may be a clinically relevant and practical method for improving the retention and survival of teeth with compromised PDL after delayed replantation following traumatic avulsion.
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Affiliation(s)
- Ahmed Elhakim
- Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea
- Department of Endodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
| | - Sunil Kim
- Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea
| | - Su-Jung Shin
- Department of Conservative Dentistry, Gangnam Severance Dental Hospital, Yonsei University College of Dentistry, Seoul, Korea
| | - Han-Sung Jung
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research center, Oral Science Research Center, BK21 FOUR project, Yonsei University College of Dentistry, Seoul, Korea
| | - Euiseong Kim
- Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea
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Pinto-Cardoso R, Bessa-Andrês C, Correia-de-Sá P, Bernardo Noronha-Matos J. Could hypoxia rehabilitate the osteochondral diseased interface? Lessons from the interplay of hypoxia and purinergic signals elsewhere. Biochem Pharmacol 2023:115646. [PMID: 37321413 DOI: 10.1016/j.bcp.2023.115646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/03/2023] [Accepted: 06/07/2023] [Indexed: 06/17/2023]
Abstract
The osteochondral unit comprises the articular cartilage (90%), subchondral bone (5%) and calcified cartilage (5%). All cells present at the osteochondral unit that is ultimately responsible for matrix production and osteochondral homeostasis, such as chondrocytes, osteoblasts, osteoclasts and osteocytes, can release adenine and/or uracil nucleotides to the local microenvironment. Nucleotides are released by these cells either constitutively or upon plasma membrane damage, mechanical stress or hypoxia conditions. Once in the extracellular space, endogenously released nucleotides can activate membrane-bound purinoceptors. Activation of these receptors is fine-tuning regulated by nucleotides' breakdown by enzymes of the ecto-nucleotidase cascade. Depending on the pathophysiological conditions, both the avascular cartilage and the subchondral bone subsist to significant changes in oxygen tension, which has a tremendous impact on tissue homeostasis. Cell stress due to hypoxic conditions directly influences the expression and activity of several purinergic signalling players, namely nucleotide release channels (e.g. Cx43), NTPDase enzymes and purinoceptors. This review gathers experimental evidence concerning the interplay between hypoxia and the purinergic signalling cascade contributing to osteochondral unit homeostasis. Reporting deviations to this relationship resulting from pathological alterations of articular joints may ultimately unravel novel therapeutic targets for osteochondral rehabilitation. At this point, one can only hypothesize how hypoxia mimetic conditions can be beneficial to the ex vivo expansion and differentiation of osteo- and chondro-progenitors for auto-transplantation and tissue regenerative purposes.
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Affiliation(s)
- Rui Pinto-Cardoso
- Laboratório de Farmacologia e Neurobiologia; Center for Drug Discovery and Innovative Medicines (MedInUP), Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - Catarina Bessa-Andrês
- Laboratório de Farmacologia e Neurobiologia; Center for Drug Discovery and Innovative Medicines (MedInUP), Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia; Center for Drug Discovery and Innovative Medicines (MedInUP), Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - José Bernardo Noronha-Matos
- Laboratório de Farmacologia e Neurobiologia; Center for Drug Discovery and Innovative Medicines (MedInUP), Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP).
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Zhou F, Li X, Chang X, Geng Z, Hao W, Deng J, Wong HM, Wang S. Effect of Enterococcus faecalis on osteoclastogenesis under cobalt-mimicked hypoxia in vitro. Microb Pathog 2023; 175:105964. [PMID: 36587925 DOI: 10.1016/j.micpath.2022.105964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/16/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The bone destruction in persistent apical periodontitis associated with infection and a periapical hypoxic microenvironment is not well known. Thus, we aimed to investigate the effects of Enterococcus faecalis on osteoclastogenesis under cobalt-mimicked hypoxia. MATERIALS AND METHODS Mouse bone marrow-derived macrophages (BMMs) were isolated as osteoclast precursors and stimulated by heat-killed E. faecalis in an environment of cobalt-mimicked hypoxia environment. The cell proliferation and apoptosis were detected using CCK-8 and flow cytometry, respectively. Osteoclast differentiation was determined via tartrate-resistant acid phosphatase staining (TRAP) and immunofluorescence staining. The osteoclastogenic protein and gene expressions were measured by western blotting and real-time PCR. RESULTS Under cobalt-mimicked hypoxia, E. faecalis markedly inhibited the proliferation of the BMMs and significantly promoted the apoptosis of the BMMs. The differentiation of the BMMs into osteoclasts was enhanced in the presence of the E. faecalis under hypoxia, and the expression of Blimp, c-Fos, and NFATc1 was up-regulated, while the expression of RBP-J was inhibited. CONCLUSIONS E. faecalis markedly promotes osteoclast differentiation under cobalt-mimicked hypoxia in vitro.
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Affiliation(s)
- Fengyi Zhou
- Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology of Qingdao University, Qingdao, China; Dental Digital Medicine & 3D Printing Engineering Laboratory of Qingdao, Qingdao, China
| | - Xin Li
- Department of Stomatology, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen, China; Institute of Stomatological Research, Shenzhen University, China
| | - Xiaochi Chang
- Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology of Qingdao University, Qingdao, China; Dental Digital Medicine & 3D Printing Engineering Laboratory of Qingdao, Qingdao, China
| | - Zhihao Geng
- Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Wenjing Hao
- Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology of Qingdao University, Qingdao, China
| | - Jing Deng
- Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology of Qingdao University, Qingdao, China; Dental Digital Medicine & 3D Printing Engineering Laboratory of Qingdao, Qingdao, China
| | - Hai Ming Wong
- Department of Paediatric Dentistry, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
| | - Shuai Wang
- Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology of Qingdao University, Qingdao, China; Dental Digital Medicine & 3D Printing Engineering Laboratory of Qingdao, Qingdao, China.
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Bolat N, Erzurumlu Y, Aşcı H, Özmen Ö, Üreyen Kaya B. Selenium ameliorates inflammation by decreasing autophagic flux and mitogen-activated protein kinase signalling on experimentally induced rat periapical lesions. Int Endod J 2023; 56:227-244. [PMID: 36314140 DOI: 10.1111/iej.13861] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/05/2022]
Abstract
AIM To reveal the molecular mechanisms that targets mitogen-activated protein kinase (MAPK) signalling and the autophagic flux and to investigate the possible effects of the systemic administration of selenium (Se) on experimentally induced rat periapical lesions. METHODOLOGY Thirty adult Sprague-Dawley rats were divided equally into negative control, positive control and Se groups. In the positive control and Se groups, the pulp chambers of their mandibular first molars were exposed to the oral environment to induce periapical lesions The Se group received daily intraperitoneal injections of Se at a dose of 0.1 mg kg-1 . After 28 days, the amount of bone destruction; severity of inflammation; penetration of microorganisms along the root canal; collagen degradation in periodontal ligament; interleukin (IL)-6, hypoxia-inducible factor-1 (HIF-1), cyclooxygenase-2 (COX-2) and caspase-3 expression; autophagic flux; and p38 MAPK signalling were evaluated using radiographic, histopathological, Gram staining, picrosirius red stain, immunohistochemical, quantitative real-time polymerase chain (qRT-PCR) and Western blot methods, respectively. These data were analysed through the Kruskal-Wallis and Dunnett's tests (p < .05). RESULTS The area of radiographic periapical bone loss, histopathological scores, the area of periapical bone loss and the scores for the bacteria localisation, the intensity of immunohistochemical staining for IL-6, HIF-1, COX-2 and caspase-3 in the Se group was significantly less than those of the positive control group (p < .01). The mRNA expression levels of Beclin-1, Atg3, Atg5, Atg7 and Atg16L1 were lower in the Se group than in the positive control group (p < .01). The protein expressions of Beclin-1, Atg5 and LC3-II, the phosphorylation ratio of the p38 MAPK and the ratios of LC3II/LC3I were significantly higher (p < .05) in the positive control and Se groups. On the contrary, the expression of the p62/SQSTM1 protein was significantly lower (p < .05) in the positive control and Se groups than in the negative control group. CONCLUSION The induction of periapical lesions in rats increased autophagic flux and activated p38 MAPK signal transduction processes. Se suppressed the inflammatory process, reduced bone destruction and both the autophagic flux and p38 MAPK activation.
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Affiliation(s)
- Nergiz Bolat
- Department of Endodontics, Faculty of Dentistry, Suleyman Demirel University, Isparta, Turkey
| | - Yalçin Erzurumlu
- Department of Biochemistry, Faculty of Pharmacy, Suleyman Demirel University, Isparta, Turkey
| | - Halil Aşcı
- Department of Pharmacology, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey
| | - Özlem Özmen
- Department of Pathology, Faculty of Veterinary, Mehmet Akif Ersoy University, Burdur, Turkey
| | - Bulem Üreyen Kaya
- Department of Endodontics, Faculty of Dentistry, Suleyman Demirel University, Isparta, Turkey
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Babu LK, Ghosh D. Looking at Mountains: Role of Sustained Hypoxia in Regulating Bone Mineral Homeostasis in Relation to Wnt Pathway and Estrogen. Clin Rev Bone Miner Metab 2022. [DOI: 10.1007/s12018-022-09283-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Exploring the Expression of Pro-Inflammatory and Hypoxia-Related MicroRNA-20a, MicroRNA-30e, and MicroRNA-93 in Periodontitis and Gingival Mesenchymal Stem Cells under Hypoxia. Int J Mol Sci 2022; 23:ijms231810310. [PMID: 36142220 PMCID: PMC9499533 DOI: 10.3390/ijms231810310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/21/2022] [Accepted: 08/28/2022] [Indexed: 11/22/2022] Open
Abstract
Hypoxia associated with inflammation are common hallmarks observed in several diseases, and it plays a major role in the expression of non-coding RNAs, including microRNAs (miRNAs). In addition, the miRNA target genes for hypoxia-inducible factor-1α (HIF-1α) and nuclear factor of activated T cells-5 (NFAT5) modulate the adaptation to hypoxia. The objective of the present study was to explore hypoxia-related miRNA target genes for HIF-1α and NFAT5, as well as miRNA-20a, miRNA-30e, and miRNA-93 expression in periodontitis versus healthy gingival tissues and gingival mesenchymal stem cells (GMSCs) cultured under hypoxic conditions. Thus, a case-control study was conducted, including healthy and periodontitis subjects. Clinical data and gingival tissue biopsies were collected to analyze the expression of miRNA-20a, miRNA-30e, miRNA-93, HIF-1α, and NFAT5 by qRT-PCR. Subsequently, GMSCs were isolated and cultured under hypoxic conditions (1% O2) to explore the expression of the HIF-1α, NFAT5, and miRNAs. The results showed a significant upregulation of miRNA-20a (p = 0.028), miRNA-30e (p = 0.035), and miRNA-93 (p = 0.026) in periodontitis tissues compared to healthy gingival biopsies. NFAT5 mRNA was downregulated in periodontitis tissues (p = 0.037), but HIF-1α was not affected (p = 0.60). Interestingly, hypoxic GMSCs upregulated the expression of miRNA-20a and HIF-1α, but they downregulated miRNA-93e. In addition, NFAT5 mRNA expression was not affected in hypoxic GMSCs. In conclusion, in periodontitis patients, the expression of miRNA-20a, miRNA-30e, and miRNA-93 increased, but a decreased expression of NFAT5 mRNA was detected. In addition, GMSCs under hypoxic conditions upregulate the HIF-1α and increase miRNA-20a (p = 0.049) expression. This study explores the role of inflammatory and hypoxia-related miRNAs and their target genes in periodontitis and GMSCs. It is crucial to determine the potential therapeutic target of these miRNAs and hypoxia during the periodontal immune–inflammatory response, which should be analyzed in greater depth in future studies.
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Kondo T, Aoki H, Otsuka Y, Kawaguchi Y, Waguri-Nagaya Y, Aoyama M. Insulin-like growth factor 2 promotes osteoclastogenesis increasing inflammatory cytokine levels under hypoxia. J Pharmacol Sci 2022; 149:93-99. [DOI: 10.1016/j.jphs.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/02/2022] [Accepted: 03/29/2022] [Indexed: 10/18/2022] Open
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Wolf D, Muralidharan A, Mohan S. Role of prolyl hydroxylase domain proteins in bone metabolism. Osteoporos Sarcopenia 2022; 8:1-10. [PMID: 35415275 PMCID: PMC8987327 DOI: 10.1016/j.afos.2022.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 01/12/2022] [Accepted: 03/04/2022] [Indexed: 11/03/2022] Open
Abstract
Cellular metabolism requires dissolved oxygen gas. Because evolutionary refinements have constrained mammalian dissolved oxygen levels, intracellular oxygen sensors are vital for optimizing the bioenergetic and biosynthetic use of dissolved oxygen. Prolyl hydroxylase domain (PHD) homologs 1-3 (PHD1/2/3) are molecular oxygen dependent non-heme dioxygenases whose enzymatic activity is regulated by the concentration of dissolved oxygen. PHD oxygen dependency has evolved into an important intracellular oxygen sensor. The most well studied mechanism of PHD oxygen-sensing is its regulation of the hypoxia-inducible factor (HIF) hypoxia signaling pathway. Heterodimeric HIF transcription factor activity is regulated post-translationally by selective PHD proline hydroxylation of its HIF1α subunit, accelerating HIF1α ubiquitination and proteasomal degradation, preventing HIF heterodimer assembly, nuclear accumulation, and activation of its target oxygen homeostasis genes. Phd2 has been shown to be the key isoform responsible for HIF1α subunit regulation in many cell types and accordingly disruption of the Phd2 gene results in embryonic lethality. In bone cells Phd2 is expressed in high abundance and tightly regulated. Conditional disruption of the Phd1, Phd2 and/or Phd3 gene in various bone cell types using different Cre drivers reveals a major role for PHD2 in skeletal growth and development. In this review, we will summarize the state of current knowledge on the role and mechanism of action of PHD2 as oxygen sensor in regulating bone metabolism.
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Affiliation(s)
- David Wolf
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA
| | - Aruljothi Muralidharan
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA, 92354, USA
- Department Biochemistry and Orthopedic Surgery, Loma Linda University, Loma Linda, CA, 92354, USA
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Liu X, Ma C, Wang S, Liang Z, Yang J, Zhou J, Shu Y, He Z, Zong J, Wu L, Peng P, Su Y, Gao M, Shen K, Zhao H, Ruan J, Ji S, Yang Y, Tang T, Yang Z, Luo G, Zeng M, Zhang W, He B, Cheng X, Wang G, Wang L, Lyu L. Screening of osteoporosis and sarcopenia in individuals aged 50 years and older at different altitudes in Yunnan province: Protocol of a longitudinal cohort study. Front Endocrinol (Lausanne) 2022; 13:1010102. [PMID: 36452328 PMCID: PMC9704050 DOI: 10.3389/fendo.2022.1010102] [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: 08/02/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
INTRODUCTION Musculoskeletal system gradually degenerates with aging, and a hypoxia environment at a high altitude may accelerate this process. However, the comprehensive effects of high-altitude environments on bones and muscles remain unclear. This study aims to compare the differences in bones and muscles at different altitudes, and to explore the mechanism and influencing factors of the high-altitude environment on the skeletal muscle system. METHODS This is a prospective, multicenter, cohort study, which will recruit a total of 4000 participants over 50 years from 12 research centers with different altitudes (50m~3500m). The study will consist of a baseline assessment and a 5-year follow-up. Participants will undergo assessments of demographic information, anthropomorphic measures, self-reported questionnaires, handgrip muscle strength assessment (HGS), short physical performance battery (SPPB), blood sample analysis, and imaging assessments (QCT and/or DXA, US) within a time frame of 3 days after inclusion. A 5-year follow-up will be conducted to evaluate the changes in muscle size, density, and fat infiltration in different muscles; the muscle function impairment; the decrease in BMD; and the osteoporotic fracture incidence. Statistical analyses will be used to compare the research results between different altitudes. Multiple linear, logistic regression and classification tree analyses will be conducted to calculate the effects of various factors (e.g., altitude, age, and physical activity) on the skeletal muscle system in a high-altitude environment. Finally, a provisional cut-off point for the diagnosis of sarcopenia in adults at different altitudes will be calculated. ETHICS AND DISSEMINATION The study has been approved by the institutional research ethics committee of each study center (main center number: KHLL2021-KY056). Results will be disseminated through scientific conferences and peer-reviewed publications, as well as meetings with stakeholders. CLINICAL TRIAL REGISTRATION NUMBER http://www.chictr.org.cn/index.aspx, identifier ChiCTR2100052153.
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Affiliation(s)
- Xingli Liu
- Faculty of Life science and Technology, Kunming University of Science and Technology, Kunming, China
- Medical School, Kunming University of Science and Technology, Kunming, China
- Department of Radiology, The First People’s Hospital of Yunnan Province, Kunming, Yunnan, China
- Department of Radiology, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
| | - Cunwen Ma
- Department of Radiology, The People’s Hospital of Wenshan Prefecture, Wenshan, China
| | - Shiping Wang
- Department of Radiology, Anning First people’s Hospital, Kunming University of Science and Technology, Anning, China
| | - Zhengrong Liang
- Department of Radiology, Qujing Second People’s Hospital of Yunnan Province, Qujing, China
| | - Juntao Yang
- Department of Radiology, Dali Bai Autonomous Prefecture People’s Hospital, Dali, China
| | - Jun Zhou
- Department of Radiology, Xishuangbanna Dai Autonomous Prefecture People’s Hospital, Jinghong, China
| | - Yi Shu
- Department of Radiology, Southern Central Hospital of Yunnan Province, Honghe, China
| | - Zhengying He
- Department of Radiology, Diqing Tibetan Autonomous Prefecture People’s Hospital, Xianggelila, China
| | - Jilong Zong
- Department of Radiology, The First People’s Hospital of Zhaotong, Zhaotong, China
| | - Lizhi Wu
- Department of Radiology, Hekou People’s Hospital, Honghe, China
| | - Peiqian Peng
- Department of Radiology, Nujiang People’s Hospital, Nujiang, China
| | - Yi Su
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Meng Gao
- Department of Radiology, The First People’s Hospital of Yunnan Province, Kunming, Yunnan, China
- Department of Radiology, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
| | - Kaiming Shen
- Department of Radiology, The People’s Hospital of Wenshan Prefecture, Wenshan, China
| | - Hong Zhao
- Department of Radiology, Anning First people’s Hospital, Kunming University of Science and Technology, Anning, China
| | - Jilu Ruan
- Department of Radiology, Qujing Second People’s Hospital of Yunnan Province, Qujing, China
| | - Shaoxuan Ji
- Department of Radiology, Dali Bai Autonomous Prefecture People’s Hospital, Dali, China
| | - Yunhui Yang
- Department of Radiology, Xishuangbanna Dai Autonomous Prefecture People’s Hospital, Jinghong, China
| | - Taisong Tang
- Department of Radiology, Southern Central Hospital of Yunnan Province, Honghe, China
| | - Zongfa Yang
- Department of Radiology, Diqing Tibetan Autonomous Prefecture People’s Hospital, Xianggelila, China
| | - Guangyin Luo
- Department of Radiology, The First People’s Hospital of Zhaotong, Zhaotong, China
| | - Meng Zeng
- Department of Radiology, Hekou People’s Hospital, Honghe, China
| | - Weiwan Zhang
- Department of Radiology, Nujiang People’s Hospital, Nujiang, China
| | - Bo He
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Xiaoguang Cheng
- Department of Radiology, Beijing Jishuitan Hospital, Beijing, China
| | - Gang Wang
- Department of Radiology, The First People’s Hospital of Yunnan Province, Kunming, Yunnan, China
- Department of Radiology, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
- *Correspondence: Gang Wang, ; Ling Wang, ; Liang Lyu,
| | - Ling Wang
- Department of Radiology, Beijing Jishuitan Hospital, Beijing, China
- *Correspondence: Gang Wang, ; Ling Wang, ; Liang Lyu,
| | - Liang Lyu
- Faculty of Life science and Technology, Kunming University of Science and Technology, Kunming, China
- Medical School, Kunming University of Science and Technology, Kunming, China
- Department of Radiology, The First People’s Hospital of Yunnan Province, Kunming, Yunnan, China
- Department of Radiology, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
- *Correspondence: Gang Wang, ; Ling Wang, ; Liang Lyu,
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11
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Kondo T, Otsuka Y, Aoki H, Goto Y, Kawaguchi Y, Waguri-Nagaya Y, Miyazawa K, Goto S, Aoyama M. The Inducible Nitric Oxide Synthase Pathway Promotes Osteoclastogenesis under Hypoxic Culture Conditions. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:2072-2079. [PMID: 34560064 DOI: 10.1016/j.ajpath.2021.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 08/09/2021] [Accepted: 08/31/2021] [Indexed: 11/25/2022]
Abstract
Bone homeostasis depends on the balance between bone resorption by osteoclasts (OCs) and bone formation by osteoblasts. Bone resorption can become excessive under various pathologic conditions, including rheumatoid arthritis. Previous studies have shown that OC formation is promoted under hypoxia. However, the precise mechanisms behind OC formation under hypoxia have not been elucidated. The present study investigated the role of inducible nitric oxide synthase (iNOS) in OC differentiation under hypoxia. Primary bone marrow cells obtained from mice were stimulated with receptor activator of NF-κB ligand and macrophage colony-stimulating factor to induce OC differentiation. The number of OCs increased in culture under hypoxia (oxygen concentration, 5%) compared with that under normoxia (oxygen concentration, 20%). iNOS gene and protein expression increased in culture under hypoxia. Addition of an iNOS inhibitor under hypoxic conditions suppressed osteoclastogenesis. Addition of a nitric oxide donor to the normoxic culture promoted osteoclastogenesis. Furthermore, insulin-like growth factor 2 expression was significantly altered in both iNOS inhibition experiments and nitric oxide donor experiments. These data might provide clues to therapies for excessive osteoclastogenesis under several hypoxic pathologic conditions, including rheumatoid arthritis.
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Affiliation(s)
- Takao Kondo
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Yuto Otsuka
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Hiromasa Aoki
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Yoh Goto
- Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Yohei Kawaguchi
- Department of Glial Cell Biology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan; Department of Orthopaedic Surgery, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Yuko Waguri-Nagaya
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Ken Miyazawa
- Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Shigemi Goto
- Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Mineyoshi Aoyama
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan.
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12
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Impacts of Hypoxia on Osteoclast Formation and Activity: Systematic Review. Int J Mol Sci 2021; 22:ijms221810146. [PMID: 34576310 PMCID: PMC8467526 DOI: 10.3390/ijms221810146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/05/2021] [Accepted: 09/08/2021] [Indexed: 01/28/2023] Open
Abstract
Hypoxia is evident in several bone diseases which are characterized by excessive bone resorption by osteoclasts, the bone-resorbing cells. The effects of hypoxia on osteoclast formation and activities are widely studied but remain inconclusive. This systematic review discusses the studies reporting the effect of hypoxia on osteoclast differentiation and activity. A literature search for relevant studies was conducted through SCOPUS and PUBMED MEDLINE search engines. The inclusion criteria were original research articles presenting data demonstrating the effect of hypoxia or low oxygen on osteoclast formation and activity. A total of 286 studies were identified from the search, whereby 20 studies were included in this review, consisting of four in vivo studies and 16 in vitro studies. In total, 12 out of 14 studies reporting the effect of hypoxia on osteoclast activity indicated higher bone resorption under hypoxic conditions, 14 studies reported that hypoxia resulted in more osteoclasts, one study found that the number remained unchanged, and five studies indicated that the number decreased. In summary, examination of the relevant literature suggests differences in findings between studies, hence the impact of hypoxia on osteoclasts remains debatable, even though there is more evidence to suggest it promotes osteoclast differentiation and activity.
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13
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Gong XF, Li XP, Zhang LX, Center JR, Bliuc D, Shi Y, Wang HB, He L, Wu XB. Current status and distribution of hip fractures among older adults in China. Osteoporos Int 2021; 32:1785-1793. [PMID: 33655399 DOI: 10.1007/s00198-021-05849-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 01/12/2021] [Indexed: 12/13/2022]
Abstract
UNLABELLED China is a middle-risk country for hip fracture at present, which differs from previous data that it was low-risk. By 2050, the total number of hip fractures in people older than 65 years is predicted to be 1.3 million. INTRODUCTION To assess hip fracture incidence in China and examine the heterogeneity of hip fracture in seven geographical regions of China. METHODS There were 238,230 hip fracture patients aged 65 years or older from 2013 to 2016 from a large national in-patients database (HQMS) involving 30.6 million hospitalizations. Taking into account the total national hospitalization rate per calendar year, we estimated the incidence of hip fracture per 100,000 residents older than 65 years in China overall and in seven geographical Chinese regions. RESULTS The proportion of men and women older than 65 years with hip fractures was 1.00:1.95. Between 2013 and 2016, the number of hip fractures per 100,000 people age 65+ was 278. China has vast territories; the number of hip fractures per 100,000 people over 65 years old was 202 in Northeast China and 374 in Northwest China. Northwest has higher altitude, lower population density, is less developed with lower urbanization than Northeast China which is low altitude, and highly urbanized. CONCLUSIONS China should no longer be regarded as a low-risk country for hip fracture. By 2050, the total number of hip fractures in people older than 65 years in China is predicted to be 1.3 million. Higher altitude areas had higher hip fracture rates than lower altitude, higher urbanized areas.
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Affiliation(s)
- X F Gong
- Department of Orthopaedic Trauma, Beijing Jishuitan Hospital, the 4th Medical College of Peking University, Beijing, China
- Department of Orthopaedic and Trauma, Lhasa People's Hospital, Lhasa, Tibet, China
| | - X P Li
- Department of Geriatrics, Beijing Jishuitan Hospital, the 4th Medical College of Peking University, Beijing, China.
| | - L X Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, China
| | - J R Center
- Bone and Mineral Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia
| | - D Bliuc
- Bone and Mineral Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia
| | - Y Shi
- China Standard Medical Information Research Center, Shenzhen, Guangdong, China
| | - H B Wang
- Clinical Trial Unit, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - L He
- Department of Orthopaedic Trauma, Beijing Jishuitan Hospital, the 4th Medical College of Peking University, Beijing, China
| | - X B Wu
- Department of Orthopaedic Trauma, Beijing Jishuitan Hospital, the 4th Medical College of Peking University, Beijing, China.
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14
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Meng X, Wielockx B, Rauner M, Bozec A. Hypoxia-Inducible Factors Regulate Osteoclasts in Health and Disease. Front Cell Dev Biol 2021; 9:658893. [PMID: 33816509 PMCID: PMC8014084 DOI: 10.3389/fcell.2021.658893] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/18/2021] [Indexed: 12/14/2022] Open
Abstract
Hypoxia-inducible factors (HIFs) have become key transcriptional regulators of metabolism, angiogenesis, erythropoiesis, proliferation, inflammation and metastases. HIFs are tightly regulated by the tissue microenvironment. Under the influence of the hypoxic milieu, HIF proteins allow the tissue to adapt its response. This is especially critical for bone, as it constitutes a highly hypoxic environment. As such, bone structure and turnover are strongly influenced by the modulation of oxygen availability and HIFs. Both, bone forming osteoblasts and bone resorbing osteoclasts are targeted by HIFs and modulators of oxygen tension. Experimental and clinical data have delineated the importance of HIF responses in different osteoclast-mediated pathologies. This review will focus on the influence of HIF expression on the regulation of osteoclasts in homeostasis as well as during inflammatory and malignant bone diseases.
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Affiliation(s)
- Xianyi Meng
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nurnberg (FAU) and Universitatsklinikum Erlangen, Erlangen, Germany
| | - Ben Wielockx
- Institute of Clinical Chemistry and Laboratory Medicine, Technische Universität Dresden, Dresden, Germany
| | - Martina Rauner
- Department of Medicine 3 - Division of Molecular Bone Biology, Medical Faculty of the Technische Universität Dresden, Dresden, Germany
| | - Aline Bozec
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nurnberg (FAU) and Universitatsklinikum Erlangen, Erlangen, Germany
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15
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Xiao C, Bai G, Du Y, Jiang H, Yu X. Association of high HIF-1α levels in serous periodontitis with external root resorption by the NFATc1 pathway. J Mol Histol 2020; 51:649-658. [PMID: 32990833 DOI: 10.1007/s10735-020-09911-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/16/2020] [Indexed: 01/25/2023]
Abstract
Whether external root resorption is associated with hypoxia in the periodontal ligaments of teeth with severe periodontitis remains unclear. Hypoxia inducible factor-1α (HIF-1α) expression and external resorption sites in the periodontal ligaments of these teeth were observed to elaborate upon the relationship between hypoxia and external root resorption in severe periodontitis. Histological analysis was performed to observe external root resorption. The expressions of HIF-1α and Nuclear factor-activated T cells c1 (NFATc1) in the periodontal ligaments were detected by immunofluorescence, western blotting and real-time PCR. Bone marrow macrophages (BMMs) were stimulated by Porphyromonas gingivalis lipopolysaccharide (Pg.LPS) and cultured under hypoxia in vitro. High levels of HIF-1α and NFATc1 were detected in severe periodontitis. HIF-1α positive-cells were observed in the external resorption sites. Hypoxia promoted Pg.LPS-stimulated osteoclastogenesis of BMMs and bone resorption by the NFATc1 pathway. Increased HIF-1α in severe periodontitis are associated with external root resorption by the NFATc1 pathway.
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Affiliation(s)
- Changjie Xiao
- Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China
| | - Guangliang Bai
- Department of Oral Medicine, Liaocheng Peoples Hospital, Liaocheng, Shandong, People's Republic of China
| | - Yanmei Du
- Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China
| | - Huan Jiang
- Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China.
| | - Xijiao Yu
- Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China.
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16
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Hannah SS, McFadden S, McNeilly A, McClean C. "Take My Bone Away?" Hypoxia and bone: A narrative review. J Cell Physiol 2020; 236:721-740. [PMID: 32643217 DOI: 10.1002/jcp.29921] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022]
Abstract
To maintain normal cellular and physiological function, sufficient oxygen is required. Recently, evidence has suggested that hypoxia, either pathological or environmental, may influence bone health. It appears that bone cells are distinctly responsive to hypoxic stimuli; for better or worse, this is still yet to be elucidated. Hypoxia has been shown to offer potentially therapeutic effects for bone by inducing an osteogenic-angiogenic response, although, others have noted excessive osteoclastic bone resorption instead. Much evidence suggests that the hypoxic-inducible pathway is integral in mediating the changes in bone metabolism. Furthermore, many factors associated with hypoxia including changes in energy metabolism, acid-base balance and the increased generation of reactive oxygen species, are known to influence bone metabolism. This review aims to examine some of the putative mechanisms responsible for hypoxic-induced alterations of bone metabolism, with regard to osteoclasts and osteoblasts, both positive and negative.
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Affiliation(s)
- Scott S Hannah
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
| | - Sonyia McFadden
- Institute of Nursing and Health Research, Ulster University, Newtownabbey, Antrim, UK
| | - Andrea McNeilly
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
| | - Conor McClean
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
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17
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Yu X, Jiang H, Cheng G, Shang W, Zhang S. High levels of HIF-1ɑ in hypoxic dental pulps associated with teeth with severe periodontitis. J Mol Histol 2020; 51:265-275. [PMID: 32394128 DOI: 10.1007/s10735-020-09878-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/04/2020] [Indexed: 12/29/2022]
Abstract
In this study we investigated the expression of HIF-1ɑ in dental pulps of the teeth with severe periodontitis. The expression of HIF-1ɑ in dental pulps of the teeth with severe periodontitis was detected by immunohistochemistry, immunofluorescence and real-time PCR. Bone marrow macrophages (BMMs) were cultured under hypoxia in vitro. HIF-1ɑ, osteoclast-specific factors (NFATc1, CTSK and c-fos) and RANKL-induced osteoclastogenesis were evaluated by immunofluorescence, TRAP staining and western blotting. High levels of HIF-1ɑ protein were detected in dental pulps of teeth with severe periodontitis, whereas few positive HIF-1ɑ expressions were detected in healthy dental pulps. Hypoxia occurred in the dental pulps in response to heavy periodontitis. Many HIF-1ɑ-positive infiltratory inflammatory cells were observed around blood vessels. Tooth internal resorption was found in some teeth with severe periodontitis. The HIF-1ɑ levels were upregulated in BMMs under hypoxia, which also promoted osteoclast formation and resorption by NFATc1, CTSK and c-fos. Teeth with severe periodontitis show hypoxic dental pulps and increased potential of osteoclastic differentiation.
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Affiliation(s)
- Xijiao Yu
- Department of Oral Surgery, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, People's Republic of China.,Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China
| | - Huan Jiang
- Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China
| | - Guannan Cheng
- Department of Orthodontics, Weihai Stomatological Hospital, Weihai, Shandong, People's Republic of China
| | - Wenzhi Shang
- Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong, People's Republic of China.
| | - Shanyong Zhang
- Department of Oral Surgery, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, People's Republic of China.
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19
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Hameister R, Lohmann CH, Dheen ST, Singh G, Kaur C. Bone biology in postnatal Wistar rats following hypoxia-reoxygenation. Histol Histopathol 2019; 35:111-124. [PMID: 31268167 DOI: 10.14670/hh-18-143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hypoxia response pathways have a central role in normal and abnormal bone biology but the effect of systemic hypoxia-reoxygenation on bone is not clear. Following hypoxic exposure, aberrant synthesis, folding and trafficking of proteins has been reported to occur, which can result in endoplasmic reticulum (ER) stress and may finally cause cell death. This study aimed to examine the effect of systemic hypoxia-reoxygenation injury on bone biology in postnatal rats. Immunoexpression of HIF-1α and VEGF was upregulated in femurs of newborn Wistar rats in response to systemic hypoxia-reoxygenation. Along with that, increased apoptosis of osteoblast precursors, osteoblasts, osteocytes and endothelial cells was observed in comparison to femurs of control animals by transmission electron microscopy, TUNEL staining and immunoexpression of cleaved caspase-3. The viability of osteoclasts was not affected. After hypoxia-reoxygenation, ER stress was observed in the osteoblasts and osteocytes as indicated by dilatation of the ER and enhanced immunoexpression of the ER stress marker GRP78. Localisation of collagen α1 immunoreaction was widespread in the bone matrix of control femurs but was confined to the osteoblasts and osteocytes in response to hypoxia-reoxygenation. In support of these findings, in vitro work showed reduced viability of osteoblast-like SaOs-2 cells and upregulation of GRP78 protein expression in them by western blotting following exposure to hypoxia. This suggests that systemic hypoxia-reoxygenation may disturb bone biology in postnatal Wistar rats by inducing ER stress and apoptosis in osteoblasts and osteocytes, without affecting the viability of osteoclasts. More in-depth research is needed to confirm causality between ER stress and apoptosis of osteoblasts and osteocytes.
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Affiliation(s)
- Rita Hameister
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Christoph H Lohmann
- Otto-von-Guericke University, Department of Orthopaedic Surgery, Magdeburg, Germany
| | - S Thameem Dheen
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gurpal Singh
- University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, National University Health System, Singapore
| | - Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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20
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Gutjahr E, Madea B. Inflammatory reaction patterns of the lung as a response to alveolar hypoxia and their significance for the diagnosis of asphyxiation. Forensic Sci Int 2019; 297:315-325. [PMID: 30852415 DOI: 10.1016/j.forsciint.2019.02.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/30/2019] [Accepted: 02/12/2019] [Indexed: 10/27/2022]
Abstract
Providing evidence of asphyxia death is a challenging issue in forensic pathology. Besides helpful macroscopical signs (e.g. strangulation mark, lung edema), recent data from literature indicate that the time of protracted asphyxia suffices to trigger an increase of giant cells and a migration of inflammatory cells from the bone marrow to the lung, thus offering a help in diagnosis of asphyxia death. In search of new valid asphyxia markers, the present study examined this hypothesis and investigated the leading role of pre-existing lung tissue cells and their functional state in reaction patterns to asphyxia. In specimens of suffocated human lungs following a short (n = 13) and a long asphyxia terminal episode (n = 15), and controls (sudden cardiovascular (n = 11) and traumatic deaths (n = 7)), the count of alveolar phagocytes, megakaryocytes, giant and mast cells, using H&E and toluidine blue staining, was performed. To show macrophage activation, immunohistochemical stainings for CD68, late (25F9) and early (MRP-8/-14) stage inflammatory markers were used. Measuring concentration of tryptase in femoral blood acted as a parameter for mast cell degranulation and consequently their activation. Results showed the lack of specificity of macroscopical parameters despite an association of suffocation with heavy lung edema. No significant differences in the numbers of inflammatory cells in the lungs of different case groups were detected. The doubling of MRP-8- and a five-fold elevation of MRP-14-positive cells compared to cardiovascular controls, proved an early activation state of pre-exiting monocytes in protracted asphyxia. These activated monocytes induced the degranulation of mast cells, resulting in slightly elevated tryptase levels in suffocation compared to cardiovascular controls. In summary, the duration of asphyxia (max. 20 min in cases investigated) only suffices to cause changes on molecular level, being not detectable in any specific macroscopical or histological form in the lung. Despite a potential utility of this molecular insight in individual cases, these results point to the classic doctrine of the evaluation of a rounded overall picture, accentuating on the proof of the ligature tool and the marks of suffocation process.
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Affiliation(s)
- Ewgenija Gutjahr
- Institute of Forensic Medicine, University of Bonn, Stiftsplatz 12, 53111, Bonn, Germany.
| | - Burkhard Madea
- Institute of Forensic Medicine, University of Bonn, Stiftsplatz 12, 53111, Bonn, Germany
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21
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Ma Z, Yu R, Zhao J, Sun L, Jian L, Li C, Liu X. Constant hypoxia inhibits osteoclast differentiation and bone resorption by regulating phosphorylation of JNK and IκBα. Inflamm Res 2019; 68:157-166. [PMID: 30604211 DOI: 10.1007/s00011-018-1209-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/19/2018] [Accepted: 12/17/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Osteoclasts are responsible for the bone loss in rheumatoid arthritis (RA). Hypoxia has been suggested to play key roles in pathological bone loss. However, the current understanding of the effects of hypoxia on osteoclastogenesis is controversial. Effects of hypoxia on both the formation and function of osteoclasts requires examination. In the current study, we aimed to explore the effect of hypoxia on osteoclast differentiation and the underlying mechanisms. METHODS RAW264.7 cells and murine bone-marrow-derived monocytes were used to induce osteoclastogenesis in the presence of macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa B ligand (RANKL). Hypoxic conditions were maintained in a hypoxic chamber at 5% CO2 and 1% O2, balanced with N2. Osteoclasts were detected by tartrate-resistant acid phosphatase (TRAP) staining. A bone resorption assay was carried out in vitro using bone slices. RT-PCR was conducted to detect osteoclast markers and transcription factors. The phosphorylation of nuclear factor-κBα (IκBα), c-Jun N-terminal kinase (JNK), extracellular regulated protein kinase (ERK), and p38 was detected by western blotting. Mann-Whitney U test or Student's t test was used to compare differences between the two groups. RESULTS TRAP staining and the bone resorption assay revealed that hypoxia-restrained osteoclast differentiation and bone resorption. Expression of osteoclast markers including cathepsin K, RANK, and TRAP decreased during osteoclast differentiation under hypoxic conditions (all P < 0.05). Hypoxia at 1% O2 did not affect cell viability, whereas it dramatically abated RANKL-dependent phosphorylation of the JNK-mitogen-activated protein kinases (MAPK) and IκBα pathways. Moreover, the expression of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) was inhibited under hypoxic conditions (all P < 0.05). CONCLUSIONS These results suggest that constant hypoxia at 1% O2 significantly restrains osteoclast formation and resorbing function without affecting cell viability. Constant hypoxia might inhibit RANKL-induced osteoclastogenesis by regulating NFATc1 expression via interfering the phosphorylation of JNK and IκBα.
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Affiliation(s)
- Zhenzhen Ma
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China
| | - Ruohan Yu
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China
| | - Jinxia Zhao
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China
| | - Lin Sun
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China
| | - Leilei Jian
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China
| | - Changhong Li
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China.
| | - Xiangyuan Liu
- Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, 100191, China.
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22
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Abstract
Osteoclasts are defined as cells capable of excavating 3-dimensional resorption pits in bone and other mineralised tissues. They are derived from the differentiation/fusion of promonocytic precursors, and are usually large, multinucleated cells. In common with other cells from this myeloid lineage such as macrophages and dendritic cells, they are adapted to function in hypoxic, acidic environments. The process of bone resorption is rapid and is presumably highly energy-intensive, since osteoclasts must actively extrude protons to dissolve hydroxyapatite mineral, whilst secreting cathepsin K to degrade collagen, as well as maintaining a high degree of motility. Osteoclasts are well known to contain abundant mitochondria but they are also able to rely on glycolytic (anaerobic) metabolism to generate the ATP needed to power their activity. Their primary extracellular energy source appears to be glucose. Excessive accumulation of mitochondrial reactive oxygen species in osteoclasts during extended periods of high activity in oxygen-poor environments may promote apoptosis and help to limit bone resorption - a trajectory that could be termed "live fast, die young". In general, however, the metabolism of osteoclasts remains a poorly-investigated area, not least because of the technical challenges of studying actively resorbing cells in appropriate conditions.
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Affiliation(s)
- Timothy R Arnett
- Department of Cell & Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Isabel R Orriss
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK.
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23
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Ausk BJ, Worton LE, Smigiel KS, Kwon RY, Bain SD, Srinivasan S, Gardiner EM, Gross TS. Muscle paralysis induces bone marrow inflammation and predisposition to formation of giant osteoclasts. Am J Physiol Cell Physiol 2017; 313:C533-C540. [PMID: 28855162 DOI: 10.1152/ajpcell.00363.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 08/24/2017] [Accepted: 08/25/2017] [Indexed: 12/11/2022]
Abstract
Transient muscle paralysis engendered by a single injection of botulinum toxin A (BTxA) rapidly induces profound focal bone resorption within the medullary cavity of adjacent bones. While initially conceived as a model of mechanical disuse, osteoclastic resorption in this model is disproportionately severe compared with the modest gait defect that is created. Preliminary studies of bone marrow following muscle paralysis suggested acute upregulation of inflammatory cytokines, including TNF-α and IL-1. We therefore hypothesized that BTxA-induced muscle paralysis would rapidly alter the inflammatory microenvironment and the osteoclastic potential of bone marrow. We tested this hypothesis by defining the time course of inflammatory cell infiltration, osteoinflammatory cytokine expression, and alteration in osteoclastogenic potential in the tibia bone marrow following transient muscle paralysis of the calf muscles. Our findings identified inflammatory cell infiltration within 24 h of muscle paralysis. By 72 h, osteoclast fusion and pro-osteoclastic inflammatory gene expression were upregulated in tibia bone marrow. These alterations coincided with bone marrow becoming permissive to the formation of osteoclasts of greater size and greater nuclei numbers. Taken together, our data are consistent with the thesis that transient calf muscle paralysis induces acute inflammation within the marrow of the adjacent tibia and that these alterations are temporally consistent with a role in mediating muscle paralysis-induced bone resorption.
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Affiliation(s)
- Brandon J Ausk
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
| | - Leah E Worton
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
| | - Kate S Smigiel
- Department of Immunology, University of Washington, Seattle, Washington
| | - Ronald Y Kwon
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
| | - Steven D Bain
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
| | - Sundar Srinivasan
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
| | - Edith M Gardiner
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
| | - Ted S Gross
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington; and
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Hulley PA, Bishop T, Vernet A, Schneider JE, Edwards JR, Athanasou NA, Knowles HJ. Hypoxia-inducible factor 1-alpha does not regulate osteoclastogenesis but enhances bone resorption activity via prolyl-4-hydroxylase 2. J Pathol 2017; 242:322-333. [PMID: 28418093 PMCID: PMC5518186 DOI: 10.1002/path.4906] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/27/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022]
Abstract
Osteogenic-angiogenic coupling is promoted by the hypoxia-inducible factor 1-alpha (HIF-1α) transcription factor, provoking interest in HIF activation as a therapeutic strategy to improve osteoblast mineralization and treat pathological osteolysis. However, HIF also enhances the bone-resorbing activity of mature osteoclasts. It is therefore essential to determine the full effect(s) of HIF on both the formation and the bone-resorbing function of osteoclasts in order to understand how they might respond to such a strategy. Expression of HIF-1α mRNA and protein increased during osteoclast differentiation from CD14+ monocytic precursors, additionally inducing expression of the HIF-regulated glycolytic enzymes. However, HIF-1α siRNA only moderately affected osteoclast differentiation, accelerating fusion of precursor cells. HIF induction by inhibition of the regulatory prolyl-4-hydroxylase (PHD) enzymes reduced osteoclastogenesis, but was confirmed to enhance bone resorption by mature osteoclasts. Phd2+/- murine osteoclasts also exhibited enhanced bone resorption, associated with increased expression of resorption-associated Acp5, in comparison with wild-type cells from littermate controls. Phd3-/- bone marrow precursors displayed accelerated early fusion, mirroring results with HIF-1α siRNA. In vivo, Phd2+/- and Phd3-/- mice exhibited reduced trabecular bone mass, associated with reduced mineralization by Phd2+/- osteoblasts. These data indicate that HIF predominantly functions as a regulator of osteoclast-mediated bone resorption, with little effect on osteoclast differentiation. Inhibition of HIF might therefore represent an alternative strategy to treat diseases characterized by pathological levels of osteolysis. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Philippa A Hulley
- Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Tammie Bishop
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Aude Vernet
- BHF Experimental MR Unit, University of Oxford, Oxford, UK
| | | | - James R Edwards
- Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Nick A Athanasou
- Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, Nuffield Orthopaedic Centre, University of Oxford, Oxford, UK
| | - Helen J Knowles
- Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
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Knowles HJ. Hypoxia-Induced Fibroblast Growth Factor 11 Stimulates Osteoclast-Mediated Resorption of Bone. Calcif Tissue Int 2017; 100:382-391. [PMID: 28097375 PMCID: PMC5336535 DOI: 10.1007/s00223-016-0228-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 12/20/2016] [Indexed: 12/17/2022]
Abstract
Over-activation of osteoclasts is directly responsible for pathological bone loss in conditions such as rheumatoid arthritis and cancer metastasis to bone. Hypoxia is a common feature of these conditions, associated with poor prognosis, which also stimulates osteoclast-mediated bone resorption via induction of the hypoxia-inducible transcription factor HIF-1α. Here, we investigate the effects of fibroblast growth factor 11 (FGF11) on osteoclast function. FGF11 is an intracellular FGF that was induced both by hypoxia (2% O2, p < 0.01) and by inhibition of the HIF-regulating prolyl hydroxylase enzymes (CoCl2, p < 0.001) in osteoclasts. Isoform-specific siRNA demonstrated that the induction of Fgf11 mRNA expression by hypoxia is HIF-1α-dependent (p < 0.01). Hypoxic stimulation of bone resorption was inhibited in osteoclasts treated with siRNA targeting FGF11 (p < 0.05). This was at least partially due to reduced secretion of an unidentified pro-resorptive factor downstream of FGF11. FGF11 expression within hypoxic, resorbing osteoclasts co-localised with microtubule-associated alpha-tubulin. FGF11 was also abundantly expressed in osteoclasts within the rheumatoid synovium and in giant cell tumour of bone. This study suggests FGF11 as a novel factor driving pathological bone resorption in osteolytic disease and as a potential target for the development of new anti-resorptive therapeutic agents.
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Affiliation(s)
- Helen J Knowles
- Botnar Research Centre, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Headington, Oxford, OX3 7LD, UK.
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Hamada S, Ikezoe K, Hirai T, Oguma T, Tanizawa K, Inouchi M, Handa T, Oga T, Mishima M, Chin K. Evaluation of Bone Mineral Density by Computed Tomography in Patients with Obstructive Sleep Apnea. J Clin Sleep Med 2017; 12:25-34. [PMID: 26235157 DOI: 10.5664/jcsm.5386] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 06/30/2015] [Indexed: 01/06/2023]
Abstract
STUDY OBJECTIVES Clinical studies have investigated whether obstructive sleep apnea (OSA) can modulate bone metabolism but data are conflicting. Bone mineral density (BMD) measured by dual-energy x-ray absorptiometry is the standard technique for quantifying bone strength but has limitations in overweight patients (body mass index [BMI] ≥ 25 kg/m(2)). The aim of this study was to examine the association between OSA and BMD by examining CT images that allow true volumetric measurements of the bone regardless of BMI. METHODS Lumbar vertebrae BMD was evaluated in 234 persons (180 males and 54 females) by CT scan. The method was calibrated by a phantom containing a known concentration of hydroxyapatite. RESULTS BMD was lower in male patients with severe OSA (apnea-hypopnea index [AHI] ≥ 30/h) than non OSA (AHI < 5; p < 0.05), while OSA and BMD had no association in females. Linear and multiple regression analyses revealed that age (p < 0.0001, β = -0.52), hypertension (p = 0.0068, β = -0.17), and the alveolar-arterial oxygen pressure difference (A-aDO2) (p = 0.012, β = -0.15) in males were associated with BMD, while only age (p < 0.0001, β = -0.68) was associated with BMD in females. CONCLUSION Males with severe OSA had a significantly lower BMD than non OSA participants. Age, hypertension, and elevation of A-aDO2 were significant factors for BMD by CT imaging. The usefulness of measuring BMD in OSA patients by CT scanning should be studied in future.
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Affiliation(s)
- Satoshi Hamada
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Kohei Ikezoe
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Toyohiro Hirai
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Tsuyoshi Oguma
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Kiminobu Tanizawa
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Morito Inouchi
- Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tomohiro Handa
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Toru Oga
- Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Michiaki Mishima
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan
| | - Kazuo Chin
- Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Knowles HJ. Multiple Roles of Angiopoietin-Like 4 in Osteolytic Disease. Front Endocrinol (Lausanne) 2017; 8:80. [PMID: 28458654 PMCID: PMC5394121 DOI: 10.3389/fendo.2017.00080] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 03/30/2017] [Indexed: 12/17/2022] Open
Abstract
Hypoxia and the hypoxia-inducible factor (HIF) transcription factor drive pathological bone loss in conditions including rheumatoid arthritis (RA), osteoarthritis, osteoporosis, primary bone tumours, and bone metastatic cancer. There is therefore considerable interest in determining the function(s) of HIF-induced genes in these pathologies. Angiopoietin-like 4 (ANGPTL4) is an adipose-derived, HIF-1α- and PPARγ-induced gene that was originally discovered as an endocrine and autocrine/paracrine regulator of lipid metabolism. Given the inverse relationship between bone adiposity and fracture risk, ANGPTL4 might be considered a good candidate for mediating the downstream effects of HIF-1α relevant to osteolytic disease. This review will consider the possible roles of ANGPTL4 in regulation of osteoclast-mediated bone resorption, cartilage degradation, angiogenesis, and inflammation, focusing on results obtained in the study of RA. Possible roles in other musculoskeletal pathologies will also be discussed. This will highlight ANGPTL4 as a regulator of multiple disease processes, which could represent a novel therapeutic target in osteolytic musculoskeletal disease.
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Affiliation(s)
- Helen J. Knowles
- Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
- *Correspondence: Helen J. Knowles,
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Mavridou AM, Hauben E, Wevers M, Schepers E, Bergmans L, Lambrechts P. Understanding External Cervical Resorption in Vital Teeth. J Endod 2016; 42:1737-1751. [DOI: 10.1016/j.joen.2016.06.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/04/2016] [Accepted: 06/09/2016] [Indexed: 12/31/2022]
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Abstract
Bone integrity is maintained throughout life via the homeostatic actions of bone cells, namely, osteoclasts, which resorb bone, and osteoblasts, which produce bone. Disruption of this balance in favor of osteoclast activation results in pathological bone loss, which occurs in conditions including osteoporosis, rheumatoid arthritis, primary bone cancer, and cancer metastasis to bone. Hypoxia also plays a major role in these conditions, where it is associated with disease progression and poor prognosis. In recent years, considerable interest has arisen in the mechanisms whereby hypoxia and the hypoxia-inducible transcription factors, HIF-1α and HIF-2α, affect bone remodeling and bone pathologies. This review summarizes the current evidence for hypoxia-mediated regulation of osteoclast differentiation and bone resorption activity. Role(s) of HIF and HIF target genes in the formation of multinucleated osteoclasts from cells of the monocyte-macrophage lineage and in the activation of bone resorption by mature osteoclasts will be discussed. Specific attention will be paid to hypoxic metabolism and generation of ATP by osteoclasts. Hypoxia-driven increases in both glycolytic flux and mitochondrial metabolic activity, along with consequent generation of mitochondrial reactive oxygen species, have been found to be essential for osteoclast formation and resorption activity. Finally, evidence for the use of HIF inhibitors as potential therapeutic agents targeting bone resorption in osteolytic disease will be discussed.
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Affiliation(s)
- Helen J Knowles
- Botnar Research Centre, NDORMS, University of Oxford, Oxford, Oxfordshire, UK
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Proteomic study of different culture medium serum volume fractions on RANKL-dependent RAW264.7 cells differentiating into osteoclasts. Proteome Sci 2015; 13:16. [PMID: 25969670 PMCID: PMC4427947 DOI: 10.1186/s12953-015-0073-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/22/2015] [Indexed: 02/07/2023] Open
Abstract
Background Cultivation of osteoclasts is a basic tool for investigating osteolytic bone diseases. Fetal bovine serum (FBS) is the standard supplement used for in vitro cell culture medium. Typically, the serum volume fraction used for osteoclast cultivation is 10%. In this study, we investigated the use of a low serum (1% FBS) model for culturing osteoclasts. Results To confirm the validity of this model for use in osteoclast research, we compared the capacity for osteoclastogenesis and bone resorption of RANKL-induced RAW 264.7 cells cultured in medium supplemented with 10% FBS and 1% FBS. Osteoclasts were successfully generated in medium supplemented with 1% FBS, and exhibited prolonged longevity and similar bone resorbing ability to those generated in medium supplemented with 10% FBS, although the osteoclasts were smaller in size. Proteomics and bioinformatics analyses were performed to assess the suitability of osteoclasts formed in low serum-containing medium for use in research focusing on osteoclast differentiation and function. Our study demonstrated that a total of 100 proteins were differentially expressed in cells cultured in medium containing 1% FBS, of which 29 proteins were upregulated, and 71 proteins were downregulated. Bioinformatics analysis showed that the electron transport chain and oxidative phosphorylation pathways were downregulated obviously; however, the osteoclast signaling pathway was unaffected. The data have been deposited to the ProteomeXchange with identifier PXD001935. Conclusion Our study provides clear evidence of the validity of the low serum model for use in studying RANKL-dependent osteoclasts differentiation and bone resorption with the advantage of prolonged survival time. Electronic supplementary material The online version of this article (doi:10.1186/s12953-015-0073-6) contains supplementary material, which is available to authorized users.
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Abstract
Angiogenesis is a vital component of bone healing. The formation of the new blood vessels at the fracture site restores the hypoxia and nutrient deprivation found at the early stages after fracture whilst at a later stage facilitates osteogenesis by the activity of the osteoprogenitor cells. Emerging evidence suggests that there are certain molecules and gene therapies that could promote new blood vessel formation and as a consequence enhance the local bone healing response. This article summarizes the current in vivo evidence on therapeutic approaches aiming at the augmentation of the angiogenic signalling during bone repair.
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Tumor necrosis factor stimulates osteoclastogenesis from human bone marrow cells under hypoxic conditions. Exp Cell Res 2014; 321:167-77. [DOI: 10.1016/j.yexcr.2013.11.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/06/2013] [Accepted: 11/27/2013] [Indexed: 02/07/2023]
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Mestrinho LA, Runhau J, Bragança M, Niza MMRE. Risk assessment of feline tooth resorption: a Portuguese clinical case control study. J Vet Dent 2013; 30:78-83. [PMID: 24006716 DOI: 10.1177/089875641303000202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Tooth resorption (TR) is one of the most common dental diseases in cats. Determination of risk factors has not yet been fully assessed and, to the best knowledge of the authors, this disease has never been studied in Portuguese cats. The objective of this case-control study was to determine type and distribution of TR lesions, evaluate risk factors, and establish relationships between variables in this disease. The study included data from 71 cats admitted for general anesthesia for various reasons. The cats were randomly selected. The inclusion criteria were availability of clinical history and owner permission. Cats with known oral disease were not excluded from the study. All cats received ultrasonic scaling and polishing of the teeth, a thorough oral examination, and full-mouth radiographs. A strong statistical relation was found between age and TR. The age group of 10 to 15-years showed an increased risk of 6.56 times for TR occurrence compared with the group 0 to 4-years of age. Presence of gingivitis in all index levels was related to an increased risk for TR. No relation was found between age or gingivitis index and lesion type. Mandibular third premolar and molar teeth were most commonly affected by TR, especially for type 1 lesions. Canine teeth were statistically more likely to have type 2 lesions. The trend for the canine teeth to be more affected with type 2 lesions needs further verification.
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Affiliation(s)
- Lisa A Mestrinho
- Centre of Research in Veterinary Sciences, Faculty of Veterinary Medicine, Lusófona University of Humanities and Technologies, Lisboa, Portugal.
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Al Hadi H, Smerdon GR, Fox SW. Hyperbaric oxygen therapy suppresses osteoclast formation and bone resorption. J Orthop Res 2013; 31:1839-44. [PMID: 23878004 DOI: 10.1002/jor.22443] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/25/2013] [Indexed: 02/04/2023]
Abstract
The cellular and molecular mechanism through which hyperbaric oxygen therapy (HBO) improves osteonecrosis (ON) is unclear. The present study therefore examined the effect of HBO, pressure and hyperoxia on RANKL-induced osteoclast formation in RAW 264.7 cells and human peripheral blood monocytes (PBMC). Daily exposure to HBO (2.4 ATA, 97% O2 , 90 min), hyperbaric pressure (2.4 ATA, 8.8% O2 , 90 min) or normobaric hyperoxia (1 ATA, 95% O2 , 90 min) significantly decreased RANKL-induced osteoclast formation and bone resorption in normoxic conditions. HBO had a more pronounced anti-osteoclastic effect than hyperoxia or pressure alone and also directly inhibited osteoclast formation and resorption in hypoxic conditions a hallmark of many osteolytic skeletal disorders. The suppressive action of HBO was at least in part mediated through a reduction in RANK, NFATc1, and Dc-STAMP expression and inhibition of hypoxia-induced HIF-1α mRNA and protein expression. This data provides mechanistic evidence supporting the use of HBO as an adjunctive therapy to prevent osteoclast formation and bone loss associated with low oxygen partial pressure.
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Affiliation(s)
- Hadil Al Hadi
- School of Biomedical and Biological Sciences, Plymouth University, Drake Circus, Plymouth, Devon, PL4 8AA, UK
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Morten KJ, Badder L, Knowles HJ. Differential regulation of HIF-mediated pathways increases mitochondrial metabolism and ATP production in hypoxic osteoclasts. J Pathol 2013; 229:755-64. [PMID: 23303559 PMCID: PMC3618370 DOI: 10.1002/path.4159] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/02/2012] [Accepted: 12/21/2012] [Indexed: 12/14/2022]
Abstract
Inappropriate osteoclast activity instigates pathological bone loss in rheumatoid arthritis. We have investigated how osteoclasts generate sufficient ATP for the energy-intensive process of bone resorption in the hypoxic microenvironment associated with this rheumatic condition. We show that in human osteoclasts differentiated from CD14+ monocytes, hypoxia (24 h, 2% O2): (a) increases ATP production and mitochondrial electron transport chain activity (Alamar blue, O2 consumption); (b) increases glycolytic flux (glucose consumption, lactate production); and (c) increases glutamine consumption. We demonstrate that glucose, rather than glutamine, is necessary for the hypoxic increase in ATP production and also for cell survival in hypoxia. Using siRNA targeting specific isoforms of the hypoxia-inducible transcription factor HIF (HIF-1α, HIF-2α), we show that employment of selected components of the HIF-1α-mediated metabolic switch to anaerobic respiration enables osteoclasts to rapidly increase ATP production in hypoxia, while at the same time compromising long-term survival. We propose this atypical HIF-driven metabolic pathway to be an adaptive mechanism to permit rapid bone resorption in the short term while ensuring curtailment of the process in the absence of re-oxygenation. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Karl J Morten
- Nuffield Department of Obstetrics and Gynaecology, The Womens Centre, John Radcliffe Hospital, Oxford, UK
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Lu C, Saless N, Wang X, Sinha A, Decker S, Kazakia G, Hou H, Williams B, Swartz HM, Hunt TK, Miclau T, Marcucio RS. The role of oxygen during fracture healing. Bone 2013; 52:220-9. [PMID: 23063782 PMCID: PMC4827706 DOI: 10.1016/j.bone.2012.09.037] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/20/2012] [Accepted: 09/21/2012] [Indexed: 10/27/2022]
Abstract
Oxygen affects the activity of multiple skeletogenic cells and is involved in many processes that are important for fracture healing. However, the role of oxygen in fracture healing has not been fully studied. Here we systematically examine the effects of oxygen tension on fracture healing and test the ability of hyperoxia to rescue healing defects in a mouse model of ischemic fracture healing. Mice with tibia fracture were housed in custom-built gas chambers and groups breathed a constant atmosphere of 13% oxygen (hypoxia), 21% oxygen (normoxia), or 50% oxygen (hyperoxia). The influx of inflammatory cells to the fracture site, stem cell differentiation, tissue vascularization, and fracture healing were analyzed. In addition, the efficacy of hyperoxia (50% oxygen) as a treatment regimen for fracture nonunion was tested. Hypoxic animals had decreased tissue vascularity, decreased bone formation, and delayed callus remodeling. Hyperoxia increased tissue vascularization, altered fracture healing in un-complicated fractures, and improved bone repair in ischemia-induced delayed fracture union. However, neither hypoxia nor hyperoxia significantly altered chondrogenesis or osteogenesis during early stages of fracture healing, and infiltration of macrophages and neutrophils was not affected by environmental oxygen after bone injury. In conclusion, our results indicate that environmental oxygen levels affect tissue vascularization and fracture healing, and that providing oxygen when fractures are accompanied by ischemia may be beneficial.
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Affiliation(s)
- Chuanyong Lu
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
- Currently at: Department of Pathology, SUNY Downstate Medical Center, Brooklyn, NY
| | - Neema Saless
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Xiaodong Wang
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Arjun Sinha
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Sebastian Decker
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Galateia Kazakia
- Department of Radiology, University of California at San Francisco
| | - Huagang Hou
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH
| | - Benjamin Williams
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH
| | - Harold M. Swartz
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH
| | - Thomas K. Hunt
- Department of Surgery, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Theodore Miclau
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Ralph S. Marcucio
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
- Author for correspondence: Phone: 415-206-5366, Fax: 415-647-3733,
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Booij-Vrieling H, de Vries T, Schoenmaker T, Tryfonidou M, Penning L, Hazewinkel H, Everts V. Osteoclast progenitors from cats with and without tooth resorption respond differently to 1,25-dihydroxyvitamin D and interleukin-6. Res Vet Sci 2012; 92:311-6. [DOI: 10.1016/j.rvsc.2011.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 03/03/2011] [Accepted: 03/15/2011] [Indexed: 01/19/2023]
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Zhao Y, Chen G, Zhang W, Xu N, Zhu JY, Jia J, Sun ZJ, Wang YN, Zhao YF. Autophagy regulates hypoxia-induced osteoclastogenesis through the HIF-1α/BNIP3 signaling pathway. J Cell Physiol 2011; 227:639-48. [DOI: 10.1002/jcp.22768] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Reed RM, Wise RA, Dobs AS, Lechtzin N, Girgis RE. Elevated HDL cholesterol levels are associated with osteoporosis in lung transplant candidates with chronic obstructive pulmonary disease. Respir Med 2011; 104:1943-50. [PMID: 20801628 DOI: 10.1016/j.rmed.2010.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 07/12/2010] [Accepted: 08/09/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND Osteoporosis is common in advanced COPD and worsens rapidly after transplantation, potentially impairing quality of life. Increased high density lipoprotein cholesterol (HDLc) has been observed in COPD and linked with osteoporosis in the general population. This association has not been previously examined in COPD. METHODS We reviewed the records of 245 COPD patients referred for lung transplant evaluation. Osteoporosis was defined by either dual energy X-ray absorptiometry scan or use of osteoporosis medications. The presence or absence of osteoporosis could be ascertained in 152 subjects. Cholesterol values and other clinical variables were assessed for their association with osteoporosis. RESULTS Clinical factors associated with osteoporosis included lower BMI [OR 0.81, 95% CI 0.73-0.90], higher HDLc [OR 1.04, 95% CI 1.02 to 1.07], and worse lung function. HDLc was an independent predictor of OP and demonstrated an inverse linear correlation with T-scores (r = -0.21, p = 0.05), which was stronger amongst males (r = -0.45, p = 0.004). CONCLUSION In COPD patients referred for lung transplantation, osteoporosis is highly prevalent. Raised HDLc levels are common in this group and are independently associated with OP.
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Affiliation(s)
- Robert M Reed
- Johns Hopkins University School of Medicine, Division of Pulmonary and Critical Care Medicine, USA.
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Leger AJ, Altobelli A, Mosquea LM, Belanger AJ, Song A, Cheng SH, Jiang C, Yew NS. Inhibition of osteoclastogenesis by prolyl hydroxylase inhibitor dimethyloxallyl glycine. J Bone Miner Metab 2010; 28:510-9. [PMID: 20300790 DOI: 10.1007/s00774-010-0171-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 02/03/2010] [Indexed: 12/22/2022]
Abstract
Studies examining the effects of hypoxia upon osteoclast biology have consistently revealed a stimulatory effect; both osteoclast differentiation and resorption activity have been shown to be enhanced in the presence of hypoxia. In the present study we examined the effects of the hypoxia mimetics dimethyloxallyl glycine (DMOG) and desferrioxamine (DFO) upon osteoclastogenesis. In contrast to hypoxia, our studies revealed a dose-dependent inhibition of osteoclast formation from macrophages treated with DMOG and DFO. Moreover, expression of a constitutively active form of hypoxia-inducible factor 1alpha (HIF-1alpha) did not enhance osteoclastogenesis and actually attenuated the differentiation process. DMOG did not affect cell viability or receptor activator of nuclear factor kappaB ligand (RANKL)-dependent phosphorylation of mitogen-activated protein (MAP) kinases. However, RANKL-dependent transcription of tartrate-resistant acid phosphatase (TRAP) was reduced in the presence of DMOG. Additionally, DMOG promoted transcription of the pro-apoptotic mediator B-Nip3. These studies suggest that a hypoxia-responsive factor other than HIF-1alpha is necessary for enhancing the formation of osteoclasts in hypoxic settings.
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Affiliation(s)
- Andrew J Leger
- Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701-9322, USA.
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Knowles HJ, Cleton-Jansen AM, Korsching E, Athanasou NA. Hypoxia-inducible factor regulates osteoclast-mediated bone resorption: role of angiopoietin-like 4. FASEB J 2010; 24:4648-59. [PMID: 20667978 PMCID: PMC2992372 DOI: 10.1096/fj.10-162230] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hypoxia and the hypoxia-inducible factor (HIF) transcription factor regulate angiogenic-osteogenic coupling and osteoclast-mediated bone resorption. To determine how HIF might coordinate osteoclast and osteoblast function, we studied angiopoietin-like 4 (ANGPTL4), the top HIF target gene in an Illumina HumanWG-6 v3.0 48k array of normoxic vs. hypoxic osteoclasts differentiated from human CD14+ monocytes (14.3-fold induction, P<0.0004). ANGPTL4 mRNA and protein were induced by 24 h at 2% O2 in human primary osteoclasts, monocytes, and osteoblasts. ANGPTL4 protein was observed by immunofluorescence in osteoclasts and osteoblasts in vivo. Normoxic inducers of HIF (CoCl2, desferrioxamine, and l-mimosine) and 100 ng/ml ANGPTL4 stimulated osteoclastic resorption 2- to 3-fold in assays of lacunar dentine resorption, without affecting osteoclast viability. Isoform-specific HIF-1α small interfering RNA ablated hypoxic induction of ANGPTL4 and of resorption, which was rescued by addition of exogenous ANGPTL4 (P<0.001). In the osteoblastic Saos2 cell line, ANGPTL4 caused a dose-dependent increase in proliferation (P<0.01, 100 ng/ml) and, at lower doses (1–25 ng/ml), mineralization. These results demonstrate that HIF is sufficient to enhance osteoclast-mediated bone resorption and that ANGPTL4 can compensate for HIF-1α deficiency with respect to stimulation of osteoclast activity and also augments osteoblast proliferation and differentiation.—Knowles, H. J., Cleton-Jansen, A.-M., Korsching, E., and Athanasou, N.A. Hypoxia-inducible factor regulates osteoclast-mediated bone resorption: role of angiopoietin-like 4.
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Affiliation(s)
- Helen J Knowles
- Botnar Research Centre, University of Oxford, Nuffield Orthopaedic Centre, Headington, Oxford, OX3 7LD, UK.
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Knowles HJ, Cleton-Jansen A, Korsching E, Athanasou NA. Hypoxia‐inducible factor regulates osteoclast‐mediated bone resorption: role of angiopoietin‐like 4. FASEB J 2010. [DOI: 10.1096/fj.10.162230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Helen J. Knowles
- Botnar Research CentreNuffield Department of Orthopaedics Rheumatology Oxford UK
| | - Anne‐Marie Cleton-Jansen
- Department of PathologyNuffield Department of Rheumatology, and Musculoskeletal Sciences Rheumatology Oxford UK
- Institute of PathologyUniversity of Muenster Muenster Germany
| | - Eberhard Korsching
- Musculoskeletal SciencesUniversity of Oxford, Nuffield Orthopaedic Centre Rheumatology Oxford UK
- Institute of PathologyUniversity of Muenster Muenster Germany
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Senn D, Schwalder P, Roux P, Bosshardt DD, Stoffel MH. Immunohistochemical Localization of Osteoclastogenic Cell Mediators in Feline Tooth Resorption and Healthy Teeth. J Vet Dent 2010. [DOI: 10.1177/089875641002700201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Tooth resorption is among the most common and most challenging problems in feline dentistry. It is a progressive disease eventually leading to tooth loss and often root replacement. The etiology of tooth resorption remains obscure and to date no effective therapeutic approach is known. The present study is aimed at assessing the reliability of radiographic imaging and addressing the possible involvement of receptor activator of NFκB (RANK), its ligand (RANKL), and osteoprotegerin (OPG) in the process of tooth resorption. Teeth from 8 cats were investigated by means of radiographs and paraffin sections followed by immunolabeling. Six cats were diagnosed with tooth resorption based on histopathologic and radiographic findings. Samples were classified according to a four-stage diagnostic system. Radiologic assessment of tooth resorption correlated very strongly with histopathologic findings. Tooth resorption was accompanied by a strong staining with all three antibodies used, especially with anti-RANK and anti-RANKL antibodies. The presence of OPG and RANKL at the resorption site is indicative of repair attempts by fibroblasts and stromal cells. These findings should be extended by further investigations in order to elucidate the pathophysiologic processes underlying tooth resorption that might lead to prophylactic and/or therapeutic measures.
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Affiliation(s)
- David Senn
- From the Division of Small Animal Surgery, and the Division of Veterinary Anatomy (Stoffel), University of Berne Veterinary School, POB 846, CH-3001 Bern, Switzerland; and, Department of Oral Surgery and Stomatology and Department of Periodontology (Bosshardt), University of Berne, School of Dental Medicine, Freiburgstrasse 7, CH-3010 Bern, Switzerland
| | - Peter Schwalder
- From the Division of Small Animal Surgery, and the Division of Veterinary Anatomy (Stoffel), University of Berne Veterinary School, POB 846, CH-3001 Bern, Switzerland; and, Department of Oral Surgery and Stomatology and Department of Periodontology (Bosshardt), University of Berne, School of Dental Medicine, Freiburgstrasse 7, CH-3010 Bern, Switzerland
| | - Philippe Roux
- From the Division of Small Animal Surgery, and the Division of Veterinary Anatomy (Stoffel), University of Berne Veterinary School, POB 846, CH-3001 Bern, Switzerland; and, Department of Oral Surgery and Stomatology and Department of Periodontology (Bosshardt), University of Berne, School of Dental Medicine, Freiburgstrasse 7, CH-3010 Bern, Switzerland
| | - Dieter D. Bosshardt
- From the Division of Small Animal Surgery, and the Division of Veterinary Anatomy (Stoffel), University of Berne Veterinary School, POB 846, CH-3001 Bern, Switzerland; and, Department of Oral Surgery and Stomatology and Department of Periodontology (Bosshardt), University of Berne, School of Dental Medicine, Freiburgstrasse 7, CH-3010 Bern, Switzerland
| | - Michael H. Stoffel
- From the Division of Small Animal Surgery, and the Division of Veterinary Anatomy (Stoffel), University of Berne Veterinary School, POB 846, CH-3001 Bern, Switzerland; and, Department of Oral Surgery and Stomatology and Department of Periodontology (Bosshardt), University of Berne, School of Dental Medicine, Freiburgstrasse 7, CH-3010 Bern, Switzerland
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Srinivasan S, Koenigstein A, Joseph J, Sun L, Kalyanaraman B, Zaidi M, Avadhani NG. Role of mitochondrial reactive oxygen species in osteoclast differentiation. Ann N Y Acad Sci 2010; 1192:245-52. [PMID: 20392243 DOI: 10.1111/j.1749-6632.2009.05377.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Previously we showed that hypoxia-induced mitochondrial respiratory stress in RAW 264.7 macrophages and other cells caused activation of retrograde signaling (also known as mitochondrial respiratory stress signaling) and the appearance of tartrate-resistant acid phosphatase (TRAP)-positive cells. In the present study, we used N-acetyl cysteine and ascorbate (general antioxidants) and MitoQ, a mitochondria-specific antioxidant, to investigate the role of intracellular reactive oxygen species (ROS) in osteoclast differentiation. Our results show that hypoxia-mediated mitochondrial dysfunction, as tested by disruption of mitochondrial transmembrane potential, was suppressed by MitoQ as well as by the other antioxidants. These agents also suppressed the activation of mitochondrial retrograde signaling. Interestingly, in terms of molar concentrations, MitoQ was more than 1000-fold more effective than general antioxidants in suppressing the receptor activator of nuclear factor-B ligand-induced differentiation of RAW 264.7 cells into multinucleated and TRAP-positive osteoclasts. We propose that mitochondrial function and intramitochondrial ROS play important roles in osteoclastogenesis.
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Affiliation(s)
- Satish Srinivasan
- Department of Animal Biology, University of Pennsylvania, Philadelphia, PA, USA
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Reaction patterns of pulmonary macrophages in protracted asphyxiation. Int J Legal Med 2010; 124:559-68. [DOI: 10.1007/s00414-009-0410-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 12/16/2009] [Indexed: 10/19/2022]
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Knowles HJ, Athanasou NA. Acute hypoxia and osteoclast activity: a balance between enhanced resorption and increased apoptosis. J Pathol 2009; 218:256-64. [PMID: 19291710 DOI: 10.1002/path.2534] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Osteoclasts are the primary mediators of pathological bone resorption in many conditions in which micro-environmental hypoxia is associated with disease progression. However, effects of hypoxia on human osteoclast activity have not been reported. Mature human osteoclasts were differentiated from peripheral blood or obtained from giant cell tumour of bone. Osteoclasts were exposed to a constant hypoxic environment and then assessed for parameters including resorption (toluidine blue staining of dentine slices), membrane integrity (trypan blue exclusion), apoptosis (TUNEL, DAPI), and osteolysis-associated enzyme activity (TRAP, cathepsin K). 24 h exposure to 2% O(2) produced a 2.5-fold increase in resorption associated with increased TRAP and cathepsin K enzyme activity. Hypoxia-Inducible Factor-1alpha (HIF-1alpha) siRNA completely ablated the hypoxic increase in osteoclast resorption. 24 h at 2% O(2) also increased the number of osteoclasts with compromised membrane integrity from 6% to 21%, with no change in the total osteoclast number or the proportion of late-stage apoptotic cells. Transient reoxygenation returned the percentage of trypan blue-positive cells to normoxic levels, suggesting that osteoclasts can recover from the early stages of cell death. Repeated over an extended period, hypoxia/reoxygenation enhanced osteoclast differentiation at this pO(2). These data suggest that in diseased bone, where the pO(2) may fall to <or=2% O(2), a delicate balance between hypoxia-induced osteoclast activation and hypoxia-induced osteoclast apoptosis mediates pathological bone resorption.
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Affiliation(s)
- Helen J Knowles
- Botnar Research Centre, University of Oxford, Nuffield Orthopaedic Centre, Oxford, UK.
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Yamasaki N, Tsuboi H, Hirao M, Nampei A, Yoshikawa H, Hashimoto J. High oxygen tension prolongs the survival of osteoclast precursors via macrophage colony-stimulating factor. Bone 2009; 44:71-9. [PMID: 18973838 DOI: 10.1016/j.bone.2008.09.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 09/09/2008] [Accepted: 09/17/2008] [Indexed: 11/30/2022]
Abstract
The oxygen tension affects the function, differentiation, and transformation of various cells, including bone cells. In pathological conditions such as rheumatoid arthritis (RA), rapidly destructive arthropathy, and primary or metastatic tumors, severe bone destruction or osteolysis occurs. Abundant blood vessels are often observed around these destructive lesions. At such sites, we have confirmed the increased production of reactive oxygen species (ROS) induced by a high oxygen tension and/or oxidative stress, as well as numerous osteoclasts detectable by immunohistochemistry. These findings suggest that osteoclasts are influenced by the high oxygen tension in pathological bone lesions because the zone around blood vessels has a relatively high oxygen tension. In this study, we investigated the effects of oxygen tension on osteoclastogenesis by culturing human CD14-positive cells (osteoclast precursors) with or without osteoblast-like supporting cells (Saos-4/3 cells) under a normal oxygen tension (20% O(2)) or a high oxygen tension (40% O(2)). A high oxygen tension markedly prolonged the duration of osteoclast precursor formation in the presence of supporting cells, and also markedly and persistently increased the production of macrophage colony stimulating factor (M-CSF) by supporting cells. Furthermore, we found an increase of cells expressing M-CSF and cells positive for tartrate-resistant acid phosphatase (TRAP) in hypervascular destructive bone lesions of RA patients where ROS were also abundant.
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Affiliation(s)
- Naomi Yamasaki
- Department of Orthopedics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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DeLaurier A, Boyde A, Jackson B, Horton MA, Price JS. Identifying early osteoclastic resorptive lesions in feline teeth: a model for understanding the origin of multiple idiopathic root resorption. J Periodontal Res 2008; 44:248-57. [PMID: 18973532 DOI: 10.1111/j.1600-0765.2008.01123.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE Domestic cats commonly suffer from external osteoclastic tooth resorption, a disease with many similarities to human multiple idiopathic root resorption. In both diseases, it is unclear whether anatomical features of the tooth surface are associated with a predisposition for resorptive lesions. The aim of the present study was to investigate the origin and progression of early feline osteoclastic resorptive lesions in teeth exhibiting no clinical signs of disease. MATERIAL AND METHODS The entire surfaces of 138 teeth from 13 adult cats were analysed using back-scattered electron microscopy. The distribution of lesions was assessed by tooth type, location and between individuals. RESULTS Seventy-three (53%) teeth showed at least one resorptive lesion. Eleven (85%) cats had lesions, and there was a significant association between increasing age and incidence of resorptive lesions. The highest frequency occurred in mandibular molars (82%). On average, there were 3.5 lesions per tooth. Fifty-two (38%) teeth featured resorptive lesions at the cemento-enamel junction. Twenty-three per cent of teeth with resorptive lesions showed evidence of repair of lesions that was limited to the root surface. There was no evidence of repair of resorptive lesions at the cemento-enamel junction. CONCLUSION Resorption is prevalent without evidence of clinical disease, and occurred at younger ages than previously reported. It can initiate anywhere on the root surface, but lack of repair of lesions at the cemento-enamel junction indicates that mechanisms of replacement are absent or compromised in this region. Whereas resorption of the root may undergo repair, resorption at the cervix may progress to clinically evident lesions.
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Affiliation(s)
- A DeLaurier
- Bone and Mineral Centre, Department of Medicine, University College London, UK.
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Knowles HJ, Athanasou NA. Hypoxia-inducible factor is expressed in giant cell tumour of bone and mediates paracrine effects of hypoxia on monocyte-osteoclast differentiation via induction of VEGF. J Pathol 2008; 215:56-66. [PMID: 18283716 DOI: 10.1002/path.2319] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hypoxia is an important regulator of bone biology and stimulates osteoclast differentiation from monocytic precursors. Hypoxia-inducible factor (HIF) is a key pro-tumourigenic transcription factor mediating pathways of hypoxia-inducible gene expression. We have described expression of HIF-1alpha and HIF-2alpha in the multi-nucleated, osteoclast-like giant cells and the mononuclear stromal component of giant cell tumour of bone (GCTB), a locally osteolytic primary bone tumour. HIF induction was observed in culture in the osteoblastic MG-63 cell line, primary GCTB stromal cells, and monocyte-derived osteoclasts following stimulation with hypoxia (0.1% O2) or the osteoclastogenic cytokines hepatocyte growth factor (HGF) and macrophage colony-stimulating factor (M-CSF). This was accompanied by increased expression of the downstream target genes Bcl-2/adenovirus E1B 19 kD-interacting protein 3 (BNIP3), Glut-1, and vascular endothelial growth factor (VEGF). As VEGF can substitute for M-CSF to support osteoclastogenesis in the presence of receptor activator for nuclear factor kappaB ligand (RANKL), we assessed the effect of MG-63 hypoxic conditioned media on osteoclast differentiation. In the presence of RANKL, hypoxic conditioned media induced the formation of active osteoclasts, as assessed from the numbers of TRAP-positive multi-nucleated cells and the area of lacunar bone resorption, which was inhibited by co-incubation with a neutralizing anti-VEGF antibody. Targeted siRNA ablated HIF-1alpha and/or HIF-2alpha expression in MG-63 cells and reduced hypoxic secretion of VEGF. Hypoxic conditioned media from cells treated with siRNA for (HIF-1alpha + HIF-2alpha) produced a significant decrease in osteoclast number (p < 0.005) and activity (p < 0.05) in comparison with the scrambled siRNA control. These results suggest that local hypoxia could indirectly influence osteoclastogenesis via autocrine and paracrine secretion of VEGF under the control of HIF. This is potentially an important mechanism of pathogenesis for GCTB and other osteolytic lesions.
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Affiliation(s)
- H J Knowles
- Botnar Research Centre, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7LD, UK
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Srinivasan S, Avadhani NG. Hypoxia-mediated mitochondrial stress in RAW264.7 cells induces osteoclast-like TRAP-positive cells. Ann N Y Acad Sci 2008; 1117:51-61. [PMID: 18056037 DOI: 10.1196/annals.1402.067] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previously we showed that mitochondrial dysfunction induced by mitochondrial DNA depletion or treatment with electron transport chain inhibitors triggers a stress signaling involving activation of calcineurin and Ca2+-responsive factors. In this study we show that exposure of RAW 264.7 cells to hypoxia, causing increased reactive oxygen species (ROS) production and disruption of mitochondrial transmembrane potential, also induced a similar stress signaling. Hypoxia caused increased [Ca2+]c, activation of cytosolic calcineurin and induced expression of Ryanodine Receptor 2 (RyR2) gene. Prolonged hypoxia (5% O2 for 5-6 days) also induced the expression of calcitonin receptor at high levels, and those of cathepsin K, and tartarate-resistant alkaline phosphatase (TRAP) at low-moderate levels in macrophage cells. Addition of RANKL had an additive effect suggesting different mechanisms of activation. Consistent with this possibility, prolonged hypoxia induced the formation of TRAP-positive osteoclast-like cells suggesting the occurrence of an autocrine mechanism for osteoclastogenesis.
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Affiliation(s)
- Satish Srinivasan
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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