1
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Sampei C, Kato K, Arasaki Y, Kimura Y, Konno T, Otsuka K, Kohara Y, Noda M, Ezura Y, Hayata T. Gprc5a is a novel parathyroid hormone-inducible gene and negatively regulates osteoblast proliferation and differentiation. J Cell Physiol 2024; 239:e31297. [PMID: 38769895 DOI: 10.1002/jcp.31297] [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: 09/05/2023] [Revised: 04/18/2024] [Accepted: 05/02/2024] [Indexed: 05/22/2024]
Abstract
Teriparatide is a peptide derived from a parathyroid hormone (PTH) and an osteoporosis therapeutic drug with potent bone formation-promoting activity. To identify novel druggable genes that act downstream of PTH signaling and are potentially involved in bone formation, we screened PTH target genes in mouse osteoblast-like MC3T3-E1 cells. Here we show that Gprc5a, encoding an orphan G protein-coupled receptor, is a novel PTH-inducible gene and negatively regulates osteoblast proliferation and differentiation. PTH treatment induced Gprc5a expression in MC3T3-E1 cells, rat osteosarcoma ROS17/2.8 cells, and mouse femurs. Induction of Gprc5a expression by PTH occurred in the absence of protein synthesis and was mediated primarily via the cAMP pathway, suggesting that Gprc5a is a direct target of PTH signaling. Interestingly, Gprc5a expression was induced additively by co-treatment with PTH and 1α, 25-dihydroxyvitamin D3 (calcitriol), or retinoic acid in MC3T3-E1 cells. Reporter analysis of a 1 kb fragment of human GPRC5A promoter revealed that the promoter fragment showed responsiveness to PTH via the cAMP response element, suggesting that GPRC5A is also a PTH-inducible gene in humans. Gprc5a knockdown promoted cell viability and proliferation, as demonstrated by MTT and BrdU assays. Gprc5a knockdown also promoted osteoblast differentiation, as indicated by gene expression analysis and mineralization assay. Mechanistic studies showed that Gprc5a interacted with BMPR1A and suppressed BMP signaling induced by BMP-2 and constitutively active BMP receptors, ALK2 (ACVR1) Q207D and ALK3 (BMPR1A) Q233D. Thus, our results suggest that Gprc5a is a novel gene induced by PTH that acts in an inhibitory manner on both cell proliferation and osteoblast differentiation and is a candidate for drug targets for osteoporosis.
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Affiliation(s)
- Chisato Sampei
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Kosuke Kato
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Yasuhiro Arasaki
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Yuta Kimura
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Takuto Konno
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Kanon Otsuka
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Yukihiro Kohara
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Masaki Noda
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
- Center for Stem Cell and Regenerative Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Yoichi Ezura
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
- Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
- Department of Occupational Therapy, Faculty of Health and Medical Science, Teikyo Heisei University, Toshima-ku, Japan
| | - Tadayoshi Hayata
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences and Faculty of Pharmaceutical Science, Tokyo University of Science, Noda, Chiba, Japan
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
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2
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Yee CS, Meliadis C, Kaya S, Chang W, Alliston T. The osteocytic actions of glucocorticoids on bone mass, mechanical properties, or perilacunar remodeling outcomes are not rescued by PTH(1-34). Front Endocrinol (Lausanne) 2024; 15:1342938. [PMID: 39092287 PMCID: PMC11291448 DOI: 10.3389/fendo.2024.1342938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 06/26/2024] [Indexed: 08/04/2024] Open
Abstract
Glucocorticoids (GC) and parathyroid hormone (PTH) are widely used therapeutic endocrine hormones where their effects on bone and joint arise from actions on multiple skeletal cell types. In osteocytes, GC and PTH exert opposing effects on perilacunar canalicular remodeling (PLR). Suppressed PLR can impair bone quality and joint homeostasis, including in GC-induced osteonecrosis. However, combined effects of GC and PTH on PLR are unknown. Given the untapped potential to target osteocytes to improve skeletal health, this study sought to test the feasibility of therapeutically mitigating PLR suppression. Focusing on subchondral bone and joint homeostasis, we hypothesize that PTH(1-34), a PLR agonist, could rescue GC-suppressed PLR. The skeletal effects of GC and PTH(1-34), alone or combined, were examined in male and female mice by micro-computed tomography, mechanical testing, histology, and gene expression analysis. For each outcome, females were more responsive to GC and PTH(1-34) than males. GC and PTH(1-34) exerted regional differences, with GC increasing trabecular bone volume but reducing cortical bone thickness, stiffness, and ultimate force. Despite PTH(1-34)'s anabolic effects on trabecular bone, it did not rescue GC's catabolic effects on cortical bone. Likewise, cartilage integrity and subchondral bone apoptosis, tartrate-resistant acid phosphatase (TRAP) activity, and osteocyte lacunocanalicular networks showed no evidence that PTH(1-34) could offset GC-dependent effects. Rather, GC and PTH(1-34) each increased cortical bone gene expression implicated in bone resorption by osteoclasts and osteocytes, including Acp5, Mmp13, Atp6v0d2, Ctsk, differences maintained when GC and PTH(1-34) were combined. Since PTH(1-34) is insufficient to rescue GC's effects on young female mouse bone, future studies are needed to determine if osteocyte PLR suppression, due to GC, aging, or other factors, can be offset by a PLR agonist.
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Affiliation(s)
- Cristal S. Yee
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Christoforos Meliadis
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Serra Kaya
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Wenhan Chang
- Endocrine Research Unit, San Francisco Veterans Affairs Medical Center, University of California, San Francisco, CA, United States
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
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3
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Paschold A, Schäffler M, Miao X, Gardon L, Krüger S, Heise H, Röhr MIS, Ott M, Strodel B, Binder WH. Photocontrolled Reversible Amyloid Fibril Formation of Parathyroid Hormone-Derived Peptides. Bioconjug Chem 2024; 35:981-995. [PMID: 38865349 PMCID: PMC11261605 DOI: 10.1021/acs.bioconjchem.4c00188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/21/2024] [Accepted: 05/24/2024] [Indexed: 06/14/2024]
Abstract
Peptide fibrillization is crucial in biological processes such as amyloid-related diseases and hormone storage, involving complex transitions between folded, unfolded, and aggregated states. We here employ light to induce reversible transitions between aggregated and nonaggregated states of a peptide, linked to the parathyroid hormone (PTH). The artificial light-switch 3-{[(4-aminomethyl)phenyl]diazenyl}benzoic acid (AMPB) is embedded into a segment of PTH, the peptide PTH25-37, to control aggregation, revealing position-dependent effects. Through in silico design, synthesis, and experimental validation of 11 novel PTH25-37-derived peptides, we predict and confirm the amyloid-forming capabilities of the AMPB-containing peptides. Quantum-chemical studies shed light on the photoswitching mechanism. Solid-state NMR studies suggest that β-strands are aligned parallel in fibrils of PTH25-37, while in one of the AMPB-containing peptides, β-strands are antiparallel. Simulations further highlight the significance of π-π interactions in the latter. This multifaceted approach enabled the identification of a peptide that can undergo repeated phototriggered transitions between fibrillated and defibrillated states, as demonstrated by different spectroscopic techniques. With this strategy, we unlock the potential to manipulate PTH to reversibly switch between active and inactive aggregated states, representing the first observation of a photostimulus-responsive hormone.
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Affiliation(s)
- André Paschold
- Macromolecular
Chemistry, Institute of Chemistry, Faculty of Natural Science II, Martin Luther University Halle Wittenberg, von-Danckelmann-Platz 4, Halle 06120, Germany
| | - Moritz Schäffler
- Institute
of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany
- Institute
of Biological Information Processing, Structural Biochemistry (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Xincheng Miao
- Center
for Nanosystems Chemistry (CNC), Theodor-Boveri Weg, Universität Würzburg, Würzburg 97074, Germany
| | - Luis Gardon
- Institute
of Biological Information Processing, Structural Biochemistry (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität
Düsseldorf, 40225 Düsseldorf, Germany
| | - Stephanie Krüger
- Biozentrum,
Martin Luther University Halle-Wittenberg, Weinberweg 22, Halle 06120, Germany
| | - Henrike Heise
- Institute
of Biological Information Processing, Structural Biochemistry (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität
Düsseldorf, 40225 Düsseldorf, Germany
| | - Merle I. S. Röhr
- Center
for Nanosystems Chemistry (CNC), Theodor-Boveri Weg, Universität Würzburg, Würzburg 97074, Germany
| | - Maria Ott
- Institute
of Biophysics, Faculty of Natural Science I, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle 06120, Germany
| | - Birgit Strodel
- Institute
of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany
- Institute
of Biological Information Processing, Structural Biochemistry (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Wolfgang H. Binder
- Macromolecular
Chemistry, Institute of Chemistry, Faculty of Natural Science II, Martin Luther University Halle Wittenberg, von-Danckelmann-Platz 4, Halle 06120, Germany
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4
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Roberts BC, Cheong VS, Oliviero S, Arredondo Carrera HM, Wang N, Gartland A, Dall'Ara E. Combining PTH(1-34) and mechanical loading has increased benefit to tibia bone mechanics in ovariectomised mice. J Orthop Res 2024; 42:1254-1266. [PMID: 38151816 DOI: 10.1002/jor.25777] [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: 04/18/2023] [Revised: 11/29/2023] [Accepted: 12/24/2023] [Indexed: 12/29/2023]
Abstract
Combined treatment with PTH(1-34) and mechanical loading confers increased structural benefits to bone than monotherapies. However, it remains unclear how this longitudinal adaptation affects the bone mechanics. This study quantified the individual and combined longitudinal effects of PTH(1-34) and mechanical loading on the bone stiffness and strength evaluated in vivo with validated micro-finite element (microFE) models. C57BL/6 mice were ovariectomised at 14-week-old and treated either with injections of PTH(1-34), compressive tibia loading or both interventions concurrently. Right tibiae were in vivo microCT-scanned every 2 weeks from 14 until 24-week-old. MicroCT images were rigidly registered to reference tibia and the cortical organ level (whole bone) and tissue level (midshaft) morphometric properties and bone mineral content were quantified. MicroCT images were converted into voxel-based homogeneous, linear elastic microFE models to estimate the bone stiffness and strength. This approach allowed us for the first time to quantify the longitudinal changes in mechanical properties induced by combined treatments in a model of accelerated bone resorption. Both changes of stiffness and strength were higher with co-treatment than with individual therapies, consistent with increased benefits with the tibia bone mineral content and cortical area, properties strongly associated with the tibia mechanics. The longitudinal data shows that the two bone anabolics, both individually and combined, had persistent benefit on estimated mechanical properties, and that benefits (increased stiffness and strength) remained after treatment was withdrawn.
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Affiliation(s)
- Bryant C Roberts
- Division of Clinical Medicine, University of Sheffield, Sheffield, UK
- Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield, UK
- Adelaide Microscopy, Division of Research and Innovation, The University of Adelaide, Adelaide, South Australia, Australia
| | - Vee San Cheong
- Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield, UK
- Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, UK
| | - Sara Oliviero
- Division of Clinical Medicine, University of Sheffield, Sheffield, UK
- Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield, UK
| | | | - Ning Wang
- Division of Clinical Medicine, University of Sheffield, Sheffield, UK
| | - Alison Gartland
- Division of Clinical Medicine, University of Sheffield, Sheffield, UK
| | - Enrico Dall'Ara
- Division of Clinical Medicine, University of Sheffield, Sheffield, UK
- Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield, UK
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5
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Lewis JW, Frost K, Neag G, Wahid M, Finlay M, Northall EH, Abudu O, Kemble S, Davis ET, Powell E, Palmer C, Lu J, Rainger GE, Iqbal AJ, Chimen M, Mahmood A, Jones SW, Edwards JR, Naylor AJ, McGettrick HM. Therapeutic avenues in bone repair: Harnessing an anabolic osteopeptide, PEPITEM, to boost bone growth and prevent bone loss. Cell Rep Med 2024; 5:101574. [PMID: 38776873 PMCID: PMC11148860 DOI: 10.1016/j.xcrm.2024.101574] [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: 12/05/2023] [Revised: 02/29/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024]
Abstract
The existing suite of therapies for bone diseases largely act to prevent further bone loss but fail to stimulate healthy bone formation and repair. We describe an endogenous osteopeptide (PEPITEM) with anabolic osteogenic activity, regulating bone remodeling in health and disease. PEPITEM acts directly on osteoblasts through NCAM-1 signaling to promote their maturation and formation of new bone, leading to enhanced trabecular bone growth and strength. Simultaneously, PEPITEM stimulates an inhibitory paracrine loop: promoting osteoblast release of the decoy receptor osteoprotegerin, which sequesters RANKL, thereby limiting osteoclast activity and bone resorption. In disease models, PEPITEM therapy halts osteoporosis-induced bone loss and arthritis-induced bone damage in mice and stimulates new bone formation in osteoblasts derived from patient samples. Thus, PEPITEM offers an alternative therapeutic option in the management of diseases with excessive bone loss, promoting an endogenous anabolic pathway to induce bone remodeling and redress the imbalance in bone turnover.
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Affiliation(s)
- Jonathan W Lewis
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Kathryn Frost
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Georgiana Neag
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Mussarat Wahid
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Melissa Finlay
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Ellie H Northall
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Oladimeji Abudu
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Samuel Kemble
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Edward T Davis
- Royal Orthopaedic Hospital, Bristol Road, Birmingham B31 2AP, UK
| | - Emily Powell
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Charlotte Palmer
- Botnar Research Centre, University of Oxford, Oxford OX3 7LD, UK
| | - Jinsen Lu
- Botnar Research Centre, University of Oxford, Oxford OX3 7LD, UK
| | - G Ed Rainger
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Asif J Iqbal
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Myriam Chimen
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Ansar Mahmood
- Department of Trauma and Orthopaedics, University Hospitals NHS Foundation Trust, Edgbaston, Birmingham B15 2GW, UK
| | - Simon W Jones
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - James R Edwards
- Botnar Research Centre, University of Oxford, Oxford OX3 7LD, UK
| | - Amy J Naylor
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK
| | - Helen M McGettrick
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, UK.
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6
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Kawao N, Matsumura D, Yamada A, Okumoto K, Ohira T, Mizukami Y, Hashimoto D, Kaji H. Tmem119 is involved in bone anabolic effects of PTH through enhanced osteoblastic bone formation in mice. Bone 2024; 181:117040. [PMID: 38316336 DOI: 10.1016/j.bone.2024.117040] [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: 11/17/2023] [Revised: 01/10/2024] [Accepted: 02/01/2024] [Indexed: 02/07/2024]
Abstract
The intermittent administration of parathyroid hormone (PTH) exerts potent bone anabolic effects, which increase bone mineral density (BMD) and reduce fracture risk in osteoporotic patients. However, the underlying mechanisms remain unclear. Tmem119 has been proposed as a factor that is closely linked to the osteoblast phenotype, and we previously reported that PTH enhanced the expression of Tmem119 in mouse osteoblastic cells. However, roles of Tmem119 in the bone anabolic effects of PTH in vivo remain unknown. We herein investigated the roles of Tmem119 in bone anabolic effects of PTH using Tmem119-deficient mice. Tmem119 deficiency significantly reduced PTH-induced increases in trabecular bone volume and cortical BMD of femurs. Effects of Tmem119 deficiency on bone mass seemed predominant in female mice. Histomorphometric analyses with calcein labeling showed that Tmem119 deficiency significantly attenuated PTH-induced increases in the rates of bone formation and mineralization as well as numbers of osteoblasts. Moreover, Tmem119 deficiency significantly blunted PTH-induced decreases in phosphorylation of β-catenin and increases in alkaline phosphatase activity in osteoblasts. In conclusion, the present results indicate that Tmem119 is involved in bone anabolic effects of PTH through osteoblastic bone formation partly related to canonical Wnt-β-catenin signaling in mice.
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Affiliation(s)
- Naoyuki Kawao
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Daichi Matsumura
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan; Department of Orthopaedic Surgery, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Ayaka Yamada
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Katsumi Okumoto
- Life Science Research Institute, Kindai University, Osakasayama, Japan
| | - Takashi Ohira
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Yuya Mizukami
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Daiki Hashimoto
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Hiroshi Kaji
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, Osakasayama, Japan.
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7
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Zweifler LE, Sinder BP, Stephan C, Koh AJ, Do J, Ulrich E, Grewal J, Woo C, Batoon L, Kozloff K, Roca H, Mishina Y, McCauley LK. Parathyroid hormone and trabectedin have differing effects on macrophages and stress fracture repair. Bone 2024; 179:116983. [PMID: 38013019 PMCID: PMC10932746 DOI: 10.1016/j.bone.2023.116983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 10/25/2023] [Accepted: 11/23/2023] [Indexed: 11/29/2023]
Abstract
Stress fractures occur as a result of repeated mechanical stress on bone and are commonly found in the load-bearing lower extremities. Macrophages are key players in the immune system and play an important role in bone remodeling and fracture healing. However, the role of macrophages in stress fractures has not been adequately addressed. We hypothesize that macrophage infiltration into a stress fracture callus site promotes bone healing. To test this, a unilateral stress fracture induction model was employed in which the murine ulna of four-month-old, C57BL/6 J male mice was repeatedly loaded with a pre-determined force until the bone was displaced a distance below the threshold for complete fracture. Mice were treated daily with parathyroid hormone (PTH, 50 μg/kg/day) starting two days before injury and continued until 24 h before euthanasia either four or six days after injury, or treated with trabectedin (0.15 mg/kg) on the day of stress fracture and euthanized three or seven days after injury. These treatments were used due to their established effects on macrophages. While macrophages have been implicated in the anabolic effects of PTH, trabectedin, an FDA approved chemotherapeutic, compromises macrophage function and reduces bone mass. At three- and four-days post injury, callus macrophage numbers were analyzed histologically. There was a significant increase in macrophages with PTH treatment compared to vehicle in the callus site. By one week of healing, treatments differentially affected the bony callus as analyzed by microcomputed tomography. PTH enhanced callus bone volume. Conversely, callus bone volume was decreased with trabectedin treatment. Interestingly, concurrent treatment with PTH and trabectedin rescued the reduction observed in the callus with trabectedin treatment alone. This study reports on the key involvement of macrophages during stress fracture healing. Given these observed outcomes on macrophage physiology and bone healing, these findings may be important for patients actively receiving either of these FDA-approved therapeutics.
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Affiliation(s)
- Laura E Zweifler
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Benjamin P Sinder
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Chris Stephan
- Department of Orthopedic Surgery, University of Michigan, Ann Arbor, MI, United States of America
| | - Amy J Koh
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Justin Do
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Emily Ulrich
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Jobanpreet Grewal
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Cecilia Woo
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Lena Batoon
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Kenneth Kozloff
- Department of Orthopedic Surgery, University of Michigan, Ann Arbor, MI, United States of America
| | - Hernan Roca
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America.
| | - Yuji Mishina
- Department of Biologic and Materials Science, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America
| | - Laurie K McCauley
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States of America; Department of Pathology, University of Michigan, Medical School, Ann Arbor, MI, United States of America
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8
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Ding Y, Yang Y, Xu F, Tan Z, Liu X, Shao X, Kang F, Yan Z, Luo E, Wang J, Luo Z, Cai J, Jing D. Early protection against bone stress injuries by mobilization of endogenous targeted bone remodeling. iScience 2023; 26:107605. [PMID: 37664634 PMCID: PMC10470328 DOI: 10.1016/j.isci.2023.107605] [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: 03/07/2023] [Revised: 06/29/2023] [Accepted: 08/08/2023] [Indexed: 09/05/2023] Open
Abstract
Bone stress injuries are common overuse injuries, especially in soldiers, athletes, and performers. In contrast to various post-injury treatments, early protection against bone stress injuries can provide greater benefit. This study explored the early protection strategies against bone stress injuries by mobilization of endogenous targeted bone remodeling. The effects of various pharmaceutical/biophysical approaches, individual or combinational, were investigated by giving intervention before fatigue loading. We optimized the dosage and administration parameters and found that early intervention with pulsed electromagnetic field and parathyroid hormone (i.e., PEMF+PTH) resulted in the most pronounced protective effects among all the approaches against the bone stress injuries. In addition, the mechanisms by which the strategy mobilizes targeted bone remodeling and enhances the self-repair capacity of bone were systematically investigated. This study proposes strategies to reduce the incidence of bone stress injuries in high-risk populations (e.g., soldiers and athletes), particularly for those before sudden increased physical training.
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Affiliation(s)
- Yuanjun Ding
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Yongqing Yang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Fei Xu
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Zhifen Tan
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Xiyu Liu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Xi Shao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Fei Kang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Zedong Yan
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Erping Luo
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Jing Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Zhuojing Luo
- Institute of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jing Cai
- College of Basic Medicine, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Da Jing
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
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9
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Marino S, Akel N, Li S, Cregor M, Jones M, Perez B, Troncoso G, Meeks J, Stewart S, Sato AY, Nookaew I, Bellido T. Reversal of the diabetic bone signature with anabolic therapies in mice. Bone Res 2023; 11:19. [PMID: 37076478 PMCID: PMC10115794 DOI: 10.1038/s41413-023-00261-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/01/2023] [Accepted: 03/22/2023] [Indexed: 04/21/2023] Open
Abstract
The mechanisms underlying the bone disease induced by diabetes are complex and not fully understood; and antiresorptive agents, the current standard of care, do not restore the weakened bone architecture. Herein, we reveal the diabetic bone signature in mice at the tissue, cell, and transcriptome levels and demonstrate that three FDA-approved bone-anabolic agents correct it. Diabetes decreased bone mineral density (BMD) and bone formation, damaged microarchitecture, increased porosity of cortical bone, and compromised bone strength. Teriparatide (PTH), abaloparatide (ABL), and romosozumab/anti-sclerostin antibody (Scl-Ab) all restored BMD and corrected the deteriorated bone architecture. Mechanistically, PTH and more potently ABL induced similar responses at the tissue and gene signature levels, increasing both formation and resorption with positive balance towards bone gain. In contrast, Scl-Ab increased formation but decreased resorption. All agents restored bone architecture, corrected cortical porosity, and improved mechanical properties of diabetic bone; and ABL and Scl-Ab increased toughness, a fracture resistance index. Remarkably, all agents increased bone strength over the healthy controls even in the presence of severe hyperglycemia. These findings demonstrate the therapeutic value of bone anabolic agents to treat diabetes-induced bone disease and suggest the need for revisiting the approaches for the treatment of bone fragility in diabetes.
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Affiliation(s)
- Silvia Marino
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA
| | - Nisreen Akel
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA
| | - Shenyang Li
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA
| | - Meloney Cregor
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA
| | - Meghan Jones
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Betiana Perez
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gaston Troncoso
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jomeeka Meeks
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Scott Stewart
- Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Amy Y Sato
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA
| | - Intawat Nookaew
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Teresita Bellido
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA.
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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10
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Houston DA, Stephen LA, Jayash SN, Myers K, Little K, Hopkinson M, Pitsillides AA, MacRae VE, Millan JL, Staines KA, Farquharson C. Increased PHOSPHO1 and alkaline phosphatase expression during the anabolic bone response to intermittent parathyroid hormone delivery. Cell Biochem Funct 2023; 41:189-201. [PMID: 36540015 PMCID: PMC10946561 DOI: 10.1002/cbf.3772] [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: 07/19/2022] [Revised: 12/02/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Abstract
The administration of intermittent parathyroid hormone (iPTH) is anabolic to the skeleton. Recent studies with cultured osteoblasts have revealed that the expression of PHOSPHO1, a bone-specific phosphatase essential for the initiation of mineralisation, is regulated by PTH. Therefore, this study sought to determine whether the bone anabolic response to iPTH involves modulation of expression of Phospho1 and of other enzymes critical for bone matrix mineralisation. To mimic iPTH treatment, primary murine osteoblasts were challenged with 50 nM PTH for 6 h in every 48 h period for 8 days (4 cycles), 14 days (7 cycles) and 20 days (10 cycles) in total. The expression of both Phospho1 and Smpd3 was almost completely inhibited after 4 cycles, whereas 10 cycles were required to stimulate a similar response in Alpl expression. To explore the in vivo role of PHOSPHO1 in PTH-mediated osteogenesis, the effects of 14- and 28-day iPTH (80 µg/kg/day) administration was assessed in male wild-type (WT) and Phospho1-/- mice. The expression of Phospho1, Alpl, Smpd3, Enpp1, Runx2 and Trps1 expression was enhanced in the femora of WT mice following iPTH administration but remained unchanged in the femora of Phospho1-/- mice. After 28 days of iPTH administration, the anabolic response in the femora of WT was greater than that noted in Phospho1-/- mice. Specifically, cortical and trabecular bone volume/total volume, as well as cortical thickness, were increased in femora of iPTH-treated WT but not in iPTH-treated Phospho1-/- mice. Trabecular bone osteoblast number was also increased in iPTH-treated WT mice but not in iPTH-treated Phospho1-/- mice. The increased levels of Phospho1, Alpl, Enpp1 and Smpd3 in WT mice in response to iPTH administration is consistent with their contribution to the potent anabolic properties of iPTH in bone. Furthermore, as the anabolic response to iPTH was attenuated in mice deficient in PHOSPHO1, this suggests that the osteoanabolic effects of iPTH are at least partly mediated via bone mineralisation processes.
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Affiliation(s)
- Dean A. Houston
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Louise A. Stephen
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Soher N. Jayash
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Katherine Myers
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Kirsty Little
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Mark Hopkinson
- Comparative Biomedical SciencesThe Royal Veterinary CollegeLondonUK
| | | | - Vicky E. MacRae
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Jose Luis Millan
- Human Genetics ProgramSanford Burnham Prebys Medical Discovery InstituteLa JollaCaliforniaUSA
| | - Katherine A. Staines
- School of Applied Sciences, Centre for Stress and Age‐Related DiseaseUniversity of BrightonBrightonUK
| | - Colin Farquharson
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
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11
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Zeng C, Wang S, Chen F, Wang Z, Li J, Xie Z, Ma M, Wang P, Shen H, Wu Y. Alpinetin alleviates osteoporosis by promoting osteogenic differentiation in BMSCs by triggering autophagy via PKA/mTOR/ULK1 signaling. Phytother Res 2023; 37:252-270. [PMID: 36104214 PMCID: PMC10087978 DOI: 10.1002/ptr.7610] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 01/19/2023]
Abstract
Osteoporosis, a systemic bone disease that is characterized by a reduction in bone mass and destruction of bone microstructure, is becoming a serious problem worldwide. Bone marrow mesenchymal stem cells (BMSCs) can differentiate into bone-forming osteoblasts, and play an important role in maintaining homeostasis of bone metabolism, thus being a potential therapeutic target for osteoporosis. Although the phytochemical alpinetin (APT) has been reported to possess a variety of pharmacological activities, it is still unclear whether APT can influence the osteogenic differentiation of on BMSCs and if it can improve osteoporosis. In this study, we found that APT treatment was able to enhance osteogenic differentiation levels of human BMSCs in vitro and mouse ones in vivo as revealed by multiple osteogenic markers including increased alkaline phosphatase activity and osteocalcin expression. Mechanistically, the protein kinase A (PKA)/mTOR/ULK1 signaling was involved in the action of APT to enhance the osteogenic differentiation of BMSCs. In addition, oral administration of APT significantly mitigated the bone loss in a dexamethasone-induced mouse model of osteoporosis through strengthening PKA signaling and autophagy. Altogether, these data demonstrate that APT promotes osteogenic differentiation in BMSCs by augmenting the PKA/mTOR/ULK1 autophagy signaling, highlighting its potential therapeutic application for treating osteoporotic diseases.
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Affiliation(s)
- Chenying Zeng
- Center for Biotherapy, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Shan Wang
- Center for Biotherapy, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Fenglei Chen
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Ziming Wang
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Jinteng Li
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Zhongyu Xie
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Mengjun Ma
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Peng Wang
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
| | - Huiyong Shen
- Department of Orthopedics, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China.,Department of Orthopedics, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Yanfeng Wu
- Center for Biotherapy, Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, People's Republic of China
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12
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Atkinson EG, Adaway M, Horan DJ, Korff C, Klunk A, Orr AL, Ratz K, Bellido T, Plotkin LI, Robling AG, Bidwell JP. Conditional Loss of Nmp4 in Mesenchymal Stem Progenitor Cells Enhances PTH-Induced Bone Formation. J Bone Miner Res 2023; 38:70-85. [PMID: 36321253 PMCID: PMC9825665 DOI: 10.1002/jbmr.4732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/12/2022] [Accepted: 10/29/2022] [Indexed: 11/24/2022]
Abstract
Activation of bone anabolic pathways is a fruitful approach for treating severe osteoporosis, yet FDA-approved osteoanabolics, eg, parathyroid hormone (PTH), have limited efficacy. Improving their potency is a promising strategy for maximizing bone anabolic output. Nmp4 (Nuclear Matrix Protein 4) global knockout mice exhibit enhanced PTH-induced increases in trabecular bone but display no overt baseline skeletal phenotype. Nmp4 is expressed in all tissues; therefore, to determine which cell type is responsible for driving the beneficial effects of Nmp4 inhibition, we conditionally removed this gene from cells at distinct stages of osteogenic differentiation. Nmp4-floxed (Nmp4fl/fl ) mice were crossed with mice bearing one of three Cre drivers including (i) Prx1Cre+ to remove Nmp4 from mesenchymal stem/progenitor cells (MSPCs) in long bones; (ii) BglapCre+ targeting mature osteoblasts, and (iii) Dmp1Cre+ to disable Nmp4 in osteocytes. Virgin female Cre+ and Cre- mice (10 weeks of age) were sorted into cohorts by weight and genotype. Mice were administered daily injections of either human PTH 1-34 at 30 μg/kg or vehicle for 4 weeks or 7 weeks. Skeletal response was assessed using dual-energy X-ray absorptiometry, micro-computed tomography, bone histomorphometry, and serum analysis for remodeling markers. Nmp4fl/fl ;Prx1Cre+ mice virtually phenocopied the global Nmp4-/- skeleton in the femur, ie, a mild baseline phenotype but significantly enhanced PTH-induced increase in femur trabecular bone volume/total volume (BV/TV) compared with their Nmp4fl/fl ;Prx1Cre- controls. This was not observed in the spine, where Prrx1 is not expressed. Heightened response to PTH was coincident with enhanced bone formation. Conditional loss of Nmp4 from the mature osteoblasts (Nmp4fl/fl ;BglapCre+ ) failed to increase BV/TV or enhance PTH response. However, conditional disabling of Nmp4 in osteocytes (Nmp4fl/fl ;Dmp1Cre+ ) increased BV/TV without boosting response to hormone under our experimental regimen. We conclude that Nmp4-/- Prx1-expressing MSPCs drive the improved response to PTH therapy and that this gene has stage-specific effects on osteoanabolism. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Emily G. Atkinson
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
| | - Michele Adaway
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
| | - Daniel J. Horan
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
- Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, USA
| | | | - Angela Klunk
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
| | - Ashley L. Orr
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
- Present Address: Division of Biomedical Sciences, College of Osteopathic Medicine, Marian University Indianapolis, IN 46222
| | - Katherine Ratz
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
- Present Address: Division of Biomedical Sciences, College of Osteopathic Medicine, Marian University Indianapolis, IN 46222
| | - Teresita Bellido
- Department of Physiology and Cell Biology University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205
- Central Arkansas Veterans Healthcare System, Little Rock, AR 72205
| | - Lilian I. Plotkin
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
- Indiana Center for Musculoskeletal Health, IUSM
| | - Alexander G. Robling
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
- Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, IUSM
| | - Joseph P. Bidwell
- Department of Anatomy, Cell Biology, & Physiology, Indiana University School of Medicine (IUSM), Indianapolis, IN 46202
- Indiana Center for Musculoskeletal Health, IUSM
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13
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Rooney AM, McNeill TJ, Ross FP, Bostrom MPG, van der Meulen MCH. PTH Treatment Increases Cortical Bone Mass More in Response to Compression than Tension in Mice. J Bone Miner Res 2023; 38:59-69. [PMID: 36281491 DOI: 10.1002/jbmr.4728] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 10/08/2022] [Accepted: 10/19/2022] [Indexed: 01/10/2023]
Abstract
Parathyroid hormone (PTH) is an anabolic osteoporosis treatment that increases bone mass and reduces fracture risk. Clinically, the effects of PTH are site-specific, increasing bone mass more at the spine than the hip and not increasing bone mass at the radius. Differences in local loading environment between the spine, hip, and radius may help explain the variation in efficacy, as PTH and mechanical loading have been shown to synergistically increase bone mass. We hypothesized that differences in loading mode might further explain these variations. Owing to the curvature of the mouse tibia, cyclic compression of the hindlimb causes bending at the tibial midshaft, placing the anterior surface under tension and the posterior surface under compression. We investigated the combination of PTH treatment and tibial loading in an osteoblast-specific estrogen receptor-alpha knockout mouse model of low bone mass (pOC-ERαKO) and their littermate controls (LCs) and analyzed bone morphology in the tensile, compressive, and neutral regions of the tibial midshaft. We also hypothesized that pretreating wild-type C57Bl/6J (WT) mice with PTH prior to mechanical loading would enhance the synergistic anabolic effects. Compression was more anabolic than tension, and PTH enhanced the effect of loading, particularly under compression. PTH pretreatment maintained the synergistic anabolic effect for longer durations than concurrent treatment and loading alone. Together these data provide insights into more effective physical therapy and exercise regimens for patients receiving PTH treatment. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Amanda M Rooney
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Tyler J McNeill
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | | | | | - Marjolein C H van der Meulen
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
- Research Division, Hospital for Special Surgery, New York, New York, USA
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14
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Koh AJ, Nam HK, Michalski MN, Do J, McCauley LK, Hatch NE. Anabolic actions of parathyroid hormone in a hypophosphatasia mouse model. Osteoporos Int 2022; 33:2423-2433. [PMID: 35871207 PMCID: PMC9568459 DOI: 10.1007/s00198-022-06496-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 07/07/2022] [Indexed: 11/17/2022]
Abstract
UNLABELLED Hypophosphatasia, the rare heritable disorder caused by TNAP enzyme mutations, presents wide-ranging severity of bone hypomineralization and skeletal abnormalities. Intermittent PTH (1-34) increased long bone volume in Alpl-/- mice but did not alter the skull phenotype. PTH may have therapeutic value for adults with TNAP deficiency-associated osteoporosis. INTRODUCTION Hypophosphatasia is the rare heritable disorder caused by mutations in the tissue non-specific alkaline phosphatase (TNAP) enzyme leading to TNAP deficiency. Individuals with hypophosphatasia commonly present with bone hypomineralization and skeletal abnormalities. The purpose of this study was to determine the impact of intermittent PTH on the skeletal phenotype of TNAP-deficient Alpl-/- mice. METHODS Alpl-/- and Alpl+/+ (wild-type; WT) littermate mice were administered PTH (1-34) (50 µg/kg) or vehicle control from days 4 to 12 and skeletal analyses were performed including gross measurements, micro-CT, histomorphometry, and serum biochemistry. RESULTS Alpl-/- mice were smaller with shorter tibial length and skull length compared to WT mice. Tibial BV/TV was reduced in Alpl-/- mice and daily PTH (1-34) injections significantly increased BV/TV and BMD but not TMD in both WT and Alpl-/- tibiae. Trabecular spacing was not different between genotypes and was decreased by PTH in both genotypes. Serum P1NP was unchanged while TRAcP5b was significantly lower in Alpl-/- vs. WT mice, with no PTH effect, and no differences in osteoclast numbers. Skull height and width were increased in Alpl-/- vs. WT mice, and PTH increased skull width in WT but not Alpl-/- mice. Frontal skull bones in Alpl-/- mice had decreased BV/TV, BMD, and calvarial thickness vs. WT with no significant PTH effects. Lengths of cranial base bones (basioccipital, basisphenoid, presphenoid) and lengths of synchondroses (growth plates) between the cranial base bones, plus bone of the basioccipitus, were assessed. All parameters were reduced (except lengths of synchondroses, which were increased) in Alpl-/- vs. WT mice with no PTH effect. CONCLUSION PTH increased long bone volume in the Alpl-/- mice but did not alter the skull phenotype. These data suggest that PTH can have long bone anabolic activity in the absence of TNAP, and that PTH may have therapeutic value for individuals with hypophosphatasia-associated osteoporosis.
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Affiliation(s)
- Amy J Koh
- Department of Periodontology and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Hwa Kyung Nam
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Megan N Michalski
- Department of Cell Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Justin Do
- Department of Periodontology and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Laurie K McCauley
- Department of Periodontology and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.
- Department of Pathology, School of Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Nan E Hatch
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.
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