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Monzem S, Valkani D, Evans LAE, Chang YM, Pitsillides AA. Regional modular responses in different bone compartments to the anabolic effect of PTH (1-34) and axial loading in mice. Bone 2023; 170:116720. [PMID: 36848959 DOI: 10.1016/j.bone.2023.116720] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 02/27/2023]
Abstract
Beneficial effects of intermittent parathyroid hormone (PTH) on bone mass and architecture are described to either simply add to, or to synergise with those of mechanical loading. We evaluate whether interaction with in vivo loading is reinforced by PTH dosing regimen and exhibits compartment-specific sensitivities. Female 12-week-old C57Bl6 mice received daily (7/7) or interrupted 5 day/week (5/7) PTH for 3 weeks (two vehicle groups). All mice had six loading episodes (12N) applied to right tibia (left, non-loaded) for the last 2 weeks. Micro-CT scans were used to evaluate mass and architecture in almost the entire cortical and proximal trabecular regions. Epiphyseal cortical, trabecular and marrow space volumes, and bony growth-plate bridge incidence were evaluated. Statistical analyses employed a linear mixed-effects model at each percentile and 2-way ANOVA with post-hoc test for epiphyses and bridging. We found that daily PTH enhances cortical mass and modifies shape along almost the entire tibia and that these effects are partly mitigated by brief interruption in treatment. Mechanical loading alone augments cortical mass and modifies shape but only in a region proximal to the tibiofibular junction. The effect of combining load and daily PTH dosing is solely additive for cortical bone mass with no significant load: PTH interaction, but exhibits clear synergy with interrupted PTH treatment. Daily, not interrupted PTH stimulates trabecular bone gains, yet load:PTH interaction is present at limited regions with both daily and interrupted treatment. PTH treatment, but not loading, modifies epiphyseal bone but, in contrast, only loading modifies bridge number and areal density. Our findings demonstrate impressive local effects on tibial mass and shape of combined loading and PTH that are sensitive to dosing regimen and exert their effects modularly. These findings emphasise a need to clarify PTH dosing regimens and that advantages could be accrued by aligning treatment accordingly to patient requirements and life-style.
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Affiliation(s)
- Samuel Monzem
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College. Royal College Street, NW1 0TU London, United Kingdom.
| | - Dionysia Valkani
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College. Royal College Street, NW1 0TU London, United Kingdom
| | - Lucinda Anastasia Elizabeth Evans
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College. Royal College Street, NW1 0TU London, United Kingdom
| | - Yu-Mei Chang
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College. Royal College Street, NW1 0TU London, United Kingdom
| | - Andrew Anthony Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College. Royal College Street, NW1 0TU London, United Kingdom.
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Gomes AC, Sousa DM, Oliveira TC, Fonseca Ó, Pinto RJ, Silvério D, Fernandes AI, Moreira AC, Silva T, Teles MJ, Pereira L, Saraiva M, Lamghari M, Gomes MS. Serum amyloid A proteins reduce bone mass during mycobacterial infections. Front Immunol 2023; 14:1168607. [PMID: 37153579 PMCID: PMC10161249 DOI: 10.3389/fimmu.2023.1168607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/11/2023] [Indexed: 05/09/2023] Open
Abstract
Introduction Osteopenia has been associated to several inflammatory conditions, including mycobacterial infections. How mycobacteria cause bone loss remains elusive, but direct bone infection may not be required. Methods Genetically engineered mice and morphometric, transcriptomic, and functional analyses were used. Additionally, inflammatory mediators and bone turnover markers were measured in the serum of healthy controls, individuals with latent tuberculosis and patients with active tuberculosis. Results and discussion We found that infection with Mycobacterium avium impacts bone turnover by decreasing bone formation and increasing bone resorption, in an IFNγ- and TNFα-dependent manner. IFNγ produced during infection enhanced macrophage TNFα secretion, which in turn increased the production of serum amyloid A (SAA) 3. Saa3 expression was upregulated in the bone of both M. avium- and M. tuberculosis-infected mice and SAA1 and 2 proteins (that share a high homology with murine SAA3 protein) were increased in the serum of patients with active tuberculosis. Furthermore, the increased SAA levels seen in active tuberculosis patients correlated with altered serum bone turnover markers. Additionally, human SAA proteins impaired bone matrix deposition and increased osteoclastogenesis in vitro. Overall, we report a novel crosstalk between the cytokine-SAA network operating in macrophages and bone homeostasis. These findings contribute to a better understanding of the mechanisms of bone loss during infection and open the way to pharmacological intervention. Additionally, our data and disclose SAA proteins as potential biomarkers of bone loss during infection by mycobacteria.
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Affiliation(s)
- Ana Cordeiro Gomes
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IMBC – Instituto de Biologia Molecular e Celular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- *Correspondence: Ana Cordeiro Gomes,
| | - Daniela Monteiro Sousa
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto Nacional de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | | | - Óscar Fonseca
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Mestrado em Bioquímica Clínica, Universidade de Aveiro, , Aveiro, Portugal
| | - Ricardo J. Pinto
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal
| | - Diogo Silvério
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IMBC – Instituto de Biologia Molecular e Celular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Ana Isabel Fernandes
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IMBC – Instituto de Biologia Molecular e Celular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Ana C. Moreira
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IMBC – Instituto de Biologia Molecular e Celular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Tânia Silva
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Maria José Teles
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- CHUSJ – Centro Hospitalar de São João, Porto, Portugal
- EPIUnit, ISPUP - Instituto de Saúde Pública da Universidade do Porto, Porto, Portugal
| | - Luísa Pereira
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal
| | - Margarida Saraiva
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IMBC – Instituto de Biologia Molecular e Celular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Meriem Lamghari
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto Nacional de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Maria Salomé Gomes
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
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Ruan SD, Dong YZ, Lu JG, Zhao MJ, Lu WG, Feng J. Synthesis of a Novel PTH1–34 Analog with Increased Human Serum Albumin Affinity. PHARMACEUTICAL FRONTS 2021. [DOI: 10.1055/s-0041-1731299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Parathyroid hormone (PTH)1–34 is an effective peptide drug for osteoporosis therapy. However, the half-life of PTH1–34 in vivo is short, leading to the need for frequent injections of this drug during its treatment. To prolong the half-life of PTH1–34, a novel PTH1–34 analog was generated based on fatty acid generation, and its synthesis process included recombinant protein expression, side-chain modification, and peptide decoration. The PTH1–34 variant was expressed in Escherichia coli, with a single Lys (position 27) retained as a modification site. The side chain, –AEEA-γGlu-C18 diacid, was synthesized using 2-chlorotrityl chloride resin as a solid support, and then was conjugated to the PTH1-34 variant to form PTH-Lys27-AGC. Reversed-phase chromatography confirmed a high final purity (>98%) of the target compound; in vitro bioactivity tests showed that PTH-1 receptor potency of PTH-Lys27-AGC was comparable to that of the native PTH1–34. A competitive human serum albumin binding test demonstrated a high albumin affinity of PTH-Lys27-AGC in comparison to PTH1–34. In summary, we developed a novel PTH1–34 analog, PTH-Lys27-AGC, which may be a long-acting agent for osteoporosis treatment in the future.
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Affiliation(s)
- Si-Da Ruan
- China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Yuan-Zhen Dong
- China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Jian-Guang Lu
- China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Meng-Jia Zhao
- China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Wei-Gen Lu
- China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Jun Feng
- China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
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Abouelasrar Salama S, Gouwy M, Van Damme J, Struyf S. The turning away of serum amyloid A biological activities and receptor usage. Immunology 2021; 163:115-127. [PMID: 33315264 PMCID: PMC8114209 DOI: 10.1111/imm.13295] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/24/2020] [Accepted: 12/04/2020] [Indexed: 12/21/2022] Open
Abstract
Serum amyloid A (SAA) is an acute-phase protein (APP) to which multiple immunological functions have been attributed. Regardless, the true biological role of SAA remains poorly understood. SAA is remarkably conserved in mammalian evolution, thereby suggesting an important biological function. Since its discovery in the 1970s, the majority of researchers have investigated SAA using recombinant forms made available through bacterial expression. Nevertheless, recent studies indicate that these recombinant forms of SAA are unreliable. Indeed, commercial SAA variants have been shown to be contaminated with bacterial products including lipopolysaccharides and lipoproteins. As such, biological activities and receptor usage (TLR2, TLR4) revealed through the use of commercial SAA variants may not reflect the inherent nature of this APP. Within this review, we discuss the biological effects of SAA that have been demonstrated through more solid experimental approaches. SAA takes part in the innate immune response via the recruitment of leucocytes and executes, through pathogen recognition, antimicrobial activity. Knockout animal models implicate SAA in a range of functions, such as regulation of T-cell-mediated responses and monopoiesis. Moreover, through its structural motifs, not only does SAA function as an extracellular matrix protein, but it also binds extracellular matrix proteins. Finally, we here also provide an overview of definite SAA receptor-mediated functions and highlight those that are yet to be validated. The role of FPR2 in SAA-mediated leucocyte recruitment has been confirmed; nevertheless, SAA has been linked to a range of other receptors including CD36, SR-BI/II, RAGE and P2RX7.
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Affiliation(s)
- Sara Abouelasrar Salama
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
| | - Mieke Gouwy
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
| | - Jo Van Damme
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
| | - Sofie Struyf
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
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Structural Basis for Vital Function and Malfunction of Serum Amyloid A: an Acute-Phase Protein that Wears Hydrophobicity on Its Sleeve. Curr Atheroscler Rep 2020; 22:69. [PMID: 32968930 PMCID: PMC7511256 DOI: 10.1007/s11883-020-00888-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW This review addresses normal and pathologic functions of serum amyloid A (SAA), an enigmatic biomarker of inflammation and protein precursor of AA amyloidosis, a life-threatening complication of chronic inflammation. SAA is a small, highly evolutionarily conserved acute-phase protein whose plasma levels increase up to one thousand-fold in inflammation, infection, or after trauma. The advantage of this dramatic but transient increase is unclear, and the complex role of SAA in immune response is intensely investigated. This review summarizes recent advances in our understanding of the structure-function relationship of this intrinsically disordered protein, outlines its newly emerging beneficial roles in lipid transport and inflammation control, and discusses factors that critically influence its misfolding in AA amyloidosis. RECENT FINDINGS High-resolution structures of lipid-free SAA in crystals and fibrils have been determined by x-ray crystallography and electron cryo-microscopy. Low-resolution structural studies of SAA-lipid complexes, together with biochemical, cell-based, animal model, genetic, and clinical studies, have provided surprising new insights into a wide range of SAA functions. An emerging vital role of SAA is lipid encapsulation to remove cell membrane debris from sites of injury. The structural basis for this role has been proposed. The lysosomal origin of AA amyloidosis has solidified, and its molecular and cellular mechanisms have emerged. Recent studies have revealed molecular underpinnings for understanding complex functions of this Cambrian protein in lipid transport, immune response, and amyloid formation. These findings help guide the search for much-needed targeted therapies to block the protein deposition in AA amyloidosis.
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Lawenius L, Scheffler JM, Gustafsson KL, Henning P, Nilsson KH, Colldén H, Islander U, Plovier H, Cani PD, de Vos WM, Ohlsson C, Sjögren K. Pasteurized Akkermansia muciniphila protects from fat mass gain but not from bone loss. Am J Physiol Endocrinol Metab 2020; 318:E480-E491. [PMID: 31961709 PMCID: PMC7191407 DOI: 10.1152/ajpendo.00425.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 02/07/2023]
Abstract
Probiotic bacteria can protect from ovariectomy (ovx)-induced bone loss in mice. Akkermansia muciniphila is considered to have probiotic potential due to its beneficial effect on obesity and insulin resistance. The purpose of the present study was to determine if treatment with pasteurized Akkermansia muciniphila (pAkk) could prevent ovx-induced bone loss. Mice were treated with vehicle or pAkk for 4 wk, starting 3 days before ovx or sham surgery. Treatment with pAkk reduced fat mass accumulation confirming earlier findings. However, treatment with pAkk decreased trabecular and cortical bone mass in femur and vertebra of gonadal intact mice and did not protect from ovx-induced bone loss. Treatment with pAkk increased serum parathyroid hormone (PTH) levels and increased expression of the calcium transporter Trpv5 in kidney suggesting increased reabsorption of calcium in the kidneys. Serum amyloid A 3 (SAA3) can suppress bone formation and mediate the effects of PTH on bone resorption and bone loss in mice and treatment with pAkk increased serum levels of SAA3 and gene expression of Saa3 in colon. Moreover, regulatory T cells can be protective of bone and pAkk-treated mice had decreased number of regulatory T cells in mesenteric lymph nodes and bone marrow. In conclusion, treatment with pAkk protected from ovx-induced fat mass gain but not from bone loss and reduced bone mass in gonadal intact mice. Our findings with pAkk differ from some probiotics that have been shown to protect bone mass, demonstrating that not all prebiotic and probiotic factors have the same effect on bone.
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Affiliation(s)
- Lina Lawenius
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Julia M Scheffler
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Karin L Gustafsson
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Petra Henning
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Karin H Nilsson
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Hannah Colldén
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Ulrika Islander
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Hubert Plovier
- Université Catholique de Louvain, Louvain Drug Research Institute, WELBIO (Walloon Excellence in Life Sciences and BIOtechnology), Metabolism and Nutrition Research Group, Brussels, Belgium
| | - Patrice D Cani
- Université Catholique de Louvain, Louvain Drug Research Institute, WELBIO (Walloon Excellence in Life Sciences and BIOtechnology), Metabolism and Nutrition Research Group, Brussels, Belgium
| | - Willem M de Vos
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Claes Ohlsson
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Klara Sjögren
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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The host response to bacterial bone infection involves a local upregulation of several acute phase proteins. Immunobiology 2020; 225:151914. [PMID: 32098686 DOI: 10.1016/j.imbio.2020.151914] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/10/2020] [Accepted: 02/14/2020] [Indexed: 12/14/2022]
Abstract
Bone infections often become chronic and can be difficult to diagnose. In the present study, the osseous gene expression of several acute phase proteins (APPs) during osteomyelitis was investigated in a porcine model of implant associated osteomyelitis (IAO) (sampled 5, 10 and 15 days after infection) and in slaughter pigs with spontaneous hematogenous osteomyelitis, and compared to gene expression in liver tissue. Furthermore, immunohistochemical (IHC) staining of the APP complement component C3 (C3) was performed on the porcine osteomyelitis lesions together with material from human patients with chronic osteomyelitis. In the porcine bone samples a local upregulation of the expression of several APP genes, including serum amyloid A (SAA) and C3, was observed during infection. In the liver, only C-reactive protein (CRP) and Inter-Alpha-Trypsin Inhibitor Heavy Chain 4 were significantly upregulated. Serum concentrations of CRP, SAA and haptoglobin were only upregulated at day 5 in infected animals of the IAO model. This indicates a limited systemic response to osteomyelitis. Similar numbers of positive IHC stained C3 leukocytes were found in human and porcine bone samples with chronic osteomyelitis, indicating a high transcriptional value of porcine models of osteomyelitis. The local upregulation of APPs could potentially be used for diagnosing osteomyelitis.
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Abstract
Prostaglandins (PGs) are highly bioactive fatty acids. PGs, especially prostaglandin E2 (PGE2), are abundantly produced by cells of both the bone-forming (osteoblast) lineage and the bone-resorbing (osteoclast) lineage. The inducible cyclooxygenase, COX-2, is largely responsible for most PGE2 production in bone, and once released, PGE2 is rapidly degraded in vivo. COX-2 is induced by multiple agonists - hormones, growth factors, and proinflammatory factors - and the resulting PGE2 may mediate, amplify, or, as we have recently shown for parathyroid hormone (PTH), inhibit responses to these agonists. In vitro, PGE2 can directly stimulate osteoblast differentiation and, indirectly via stimulation of RANKL in osteoblastic cells, stimulate the differentiation of osteoclasts. The net balance of these two effects of PGE2 in vivo on bone formation and bone resorption has been hard to predict and, as expected for such a widespread local factor, hard to study. Some of the complexity of PGE2 actions on bone can be explained by the fact that there are four receptors for PGE2 (EP1-4). Some of the major actions of PGE2 in vitro occur via EP2 and EP4, both of which can stimulate cAMP signaling, but there are other distinct signaling pathways, important in other tissues, which have not yet been fully elucidated in bone cells. Giving PGE2 or agonists of EP2 and EP4 to accelerate bone repair has been examined with positive results. Further studies to clarify the pathways of PGE2 action in bone may allow us to identify new and more effective ways to deliver the therapeutic benefits of PGE2 in skeletal disorders.
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Affiliation(s)
- Carol Pilbeam
- Department of Medicine and Musculoskeletal Institute, UConn Health, Farmington, CT, USA.
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Li M, He Y, Tong G, Yang D. [Prolonged continuous infusion of teriparatide promotes bone metabolism in normal but not in castrated mice]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2019; 39:1045-1051. [PMID: 31640962 DOI: 10.12122/j.issn.1673-4254.2019.09.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the effects of continuous pumping of teriparatide (TPTD) on bone metabolism in ovariectomized and normal mice and provide experimental evidence for the selection of animal models for studying the effects of TPTD and its related peptides on osteoclasts. METHODS Twenty-four female C57BL mice (6-weeks old) were subjected to ovariectomy (OVX) or sham operation followed 7 days later by continuous pumping of TPTD or the solvent vehicle (VEH) via a micropump (SHAM-VEH, SHAM-TPTD, OVX-VEH, and OVX-TPTD groups; n=6). Two weeks later, the tibial and femoral bones were harvested for micro-CT scanning to measure the parameters of the tibia and the femoral cortical bone. Histopathological examinations of the tibial tissue were conducted using HE staining and TRAP staining and the number of osteoclasts and the growth plate thickness were determined. The serum Ca2 + levels of the mice were measured. The primary osteoblasts from the cranial bone were treated with estradiol (E2) and TPTD for 48 h, and the expressions of β-catenin and RANKL protein in the cells were analyzed. RESULTS The trabecular bone mass of OVX mice was significantly lower than that of sham-operated mice (P < 0.05). Continuous TPTD pumping significantly reduced tibial cancellous bone mass and femoral cortical bone area in the sham-operated mice, while in the castrated mice, TPTD pumping increased the cancellous bone mass without changing the cortical bone area. TRAP staining showed that cancellous osteoblasts in the tibia increased significantly in the castrated mice as compared with the sham-operated mice, and TPTD pumping significantly increased the number of cancellous osteoblasts in the sham-operated mice (P < 0.05). In the primary cultured osteoblasts, treatment with both E2 and TPTD obviously lowered the expression of β-catenin and increased the expression of RANKL as compared with TPTD treatment alone. CONCLUSIONS Continuous pumping of TPTD promotes bone resorption in normal mice but does not produce obvious bone resorption effect in the ovariectomized mice, suggesting that castrated mice are not suitable models for studying the effect of TPTD and the related peptides on the osteoclasts.
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Affiliation(s)
- Minghan Li
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Youhua He
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Guojun Tong
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Dehong Yang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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