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Anastasilakis AD, Tsourdi E. Τhe story of sclerostin inhibition: the past, the present, and the future. Hormones (Athens) 2024:10.1007/s42000-023-00521-y. [PMID: 38170438 DOI: 10.1007/s42000-023-00521-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
Sclerostin inhibits osteoblast activity by hampering activation of the canonical Wnt signaling pathway and simultaneously stimulates osteoclastogenesis through upregulation of the receptor activator of NFκB ligand (RANKL). Thus, antibodies against sclerostin (Scl-Abs), besides promoting bone formation, suppress bone resorption and dissociate bone formation from resorption. This dual action results in remarkable increases of bone mineral density which are of a greater magnitude compared to the other antiosteoporotic treatments and are accompanied by decreases of fracture risk at all skeletal sites. The anabolic effect subsides after the first few months of treatment and a predominantly antiresorptive effect remains after this period, limiting its use to 12 months. Furthermore, these effects are largely reversible upon discontinuation; therefore, subsequent treatment with antiresorptives is indicated to maintain or further increase the bone gains achieved. Romosozumab is currently the only Scl-Ab approved for the treatment of severe postmenopausal osteoporosis. Indications for use in other populations, such as males, premenopausal women, and patients with glucocorticoid-induced osteoporosis, are pending. Additionally, the efficacy of Scl-Abs in other bone diseases, such as osteogenesis imperfecta, hypophosphatasia, X-linked hypophosphatemia, and bone loss associated with malignancies, is under thorough investigation. Cardiovascular safety concerns currently exclude patients at high cardiovascular risk from this treatment.
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Affiliation(s)
- Athanasios D Anastasilakis
- Department of Endocrinology, 424 Military General Hospital, Ring Road, 564 29 N. Efkarpia, Thessaloniki, Greece.
| | - Elena Tsourdi
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
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Carpenter KA, Alkhatib DO, Dulion BA, Guirado E, Patel S, Chen Y, George A, Ross RD. Sclerostin antibody improves alveolar bone quality in the Hyp mouse model of X-linked hypophosphatemia (XLH). Int J Oral Sci 2023; 15:47. [PMID: 37813865 PMCID: PMC10562382 DOI: 10.1038/s41368-023-00252-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/11/2023] Open
Abstract
X-linked hypophosphatemia (XLH) is a rare disease of elevated fibroblast growth factor 23 (FGF23) production that leads to hypophosphatemia and impaired mineralization of bone and teeth. The clinical manifestations of XLH include a high prevalence of dental abscesses and periodontal disease, likely driven by poorly formed structures of the dentoalveolar complex, including the alveolar bone, cementum, dentin, and periodontal ligament. Our previous studies have demonstrated that sclerostin antibody (Scl-Ab) treatment improves phosphate homeostasis, and increases long bone mass, strength, and mineralization in the Hyp mouse model of XLH. In the current study, we investigated whether Scl-Ab impacts the dentoalveolar structures of Hyp mice. Male and female wild-type and Hyp littermates were injected with 25 mg·kg-1 of vehicle or Scl-Ab twice weekly beginning at 12 weeks of age and euthanized at 20 weeks of age. Scl-Ab increased alveolar bone mass in both male and female mice and alveolar tissue mineral density in the male mice. The positive effects of Scl-Ab were consistent with an increase in the fraction of active (nonphosphorylated) β-catenin, dentin matrix protein 1 (DMP1) and osteopontin stained alveolar osteocytes. Scl-Ab had no effect on the mass and mineralization of dentin, enamel, acellular or cellular cementum. There was a nonsignificant trend toward increased periodontal ligament (PDL) attachment fraction within the Hyp mice. Additional PDL fiber structural parameters were not affected by Scl-Ab. The current study demonstrates that Scl-Ab can improve alveolar bone in adult Hyp mice.
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Affiliation(s)
- Kelsey A Carpenter
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, USA
| | - Delia O Alkhatib
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, USA
| | - Bryan A Dulion
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, USA
| | - Elizabeth Guirado
- Department of Oral Biology, The University of Illinois at Chicago, Chicago, IL, USA
| | - Shreya Patel
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, USA
| | - Yinghua Chen
- Department of Oral Biology, The University of Illinois at Chicago, Chicago, IL, USA
| | - Anne George
- Department of Oral Biology, The University of Illinois at Chicago, Chicago, IL, USA
| | - Ryan D Ross
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, USA.
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA.
- Department of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL, USA.
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3
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Ross R, Carpenter K, Alkhatib D, Dulion B, Guirado E, Patel S, Chen Y, George A. Sclerostin antibody improves alveolar bone quality in the Hyp mouse model of X-Linked Hypophosphatemia (XLH). RESEARCH SQUARE 2023:rs.3.rs-2762671. [PMID: 37090634 PMCID: PMC10120757 DOI: 10.21203/rs.3.rs-2762671/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
X-linked hypophosphatemia (XLH) is a rare disease of elevated fibroblast growth factor 23 (FGF23) production that leads to hypophosphatemia and poor mineralization of bone and teeth. The clinical manifestations of XLH include a high prevalence of dental abscesses, likely driven by poorly formed structures of the dentoalveolar complex, including the alveolar bone, cementum, dentin, and periodontal ligament. Our previous studies have demonstrated that sclerostin antibody (Scl-Ab) treatment improves phosphate homeostasis, and increases bone mass, strength and mineralization in the Hyp mouse model of XLH. In the current study, we investigated whether Scl-Ab impacts the dentoalveolar structures of Hyp mice. Male and female wild-type and Hyp littermates were injected with 25 mg/kg of vehicle or Scl-Ab twice weekly beginning at 12 weeks of age and euthanized at 20 weeks of age. Scl-Ab increased alveolar bone mass in both male and female mice and alveolar tissue mineral density in the male mice. The positive effects of Scl-Ab were consistent with an increase in the fraction of active (non-phosphorylated) β-catenin stained alveolar osteocytes. Scl-Ab had no effect on mineralized tissues of the tooth - dentin, enamel, acellular and cellular cementum. There was a non-significant trend toward increased periodontal ligament (PDL) attachment fraction within the Hyp mice. Additional PDL fibral structural parameters were not affected by Scl-Ab. The current study demonstrates that Scl-Ab can improve alveolar bone in the Hyp mouse model of XLH.
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Affiliation(s)
| | | | | | | | | | | | - Yinghua Chen
- University of Illinois Chicago College of Dentistry
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Yu S, Li D, Zhang N, Ni S, Sun M, Wang L, Xiao H, Liu D, Liu J, Yu Y, Zhang Z, Yeung STY, Zhang S, Lu A, Zhang Z, Zhang B, Zhang G. Drug discovery of sclerostin inhibitors. Acta Pharm Sin B 2022; 12:2150-2170. [PMID: 35646527 PMCID: PMC9136615 DOI: 10.1016/j.apsb.2022.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/03/2021] [Accepted: 12/16/2021] [Indexed: 12/18/2022] Open
Abstract
Sclerostin, a protein secreted from osteocytes, negatively regulates the WNT signaling pathway by binding to the LRP5/6 co-receptors and further inhibits bone formation and promotes bone resorption. Sclerostin contributes to musculoskeletal system-related diseases, making it a promising therapeutic target for the treatment of WNT-related bone diseases. Additionally, emerging evidence indicates that sclerostin contributes to the development of cancers, obesity, and diabetes, suggesting that it may be a promising therapeutic target for these diseases. Notably, cardiovascular diseases are related to the protective role of sclerostin. In this review, we summarize three distinct types of inhibitors targeting sclerostin, monoclonal antibodies, aptamers, and small-molecule inhibitors, from which monoclonal antibodies have been developed. As the first-in-class sclerostin inhibitor approved by the U.S. FDA, the monoclonal antibody romosozumab has demonstrated excellent effectiveness in the treatment of postmenopausal osteoporosis; however, it conferred high cardiovascular risk in clinical trials. Furthermore, romosozumab could only be administered by injection, which may cause compliance issues for patients who prefer oral therapy. Considering these above safety and compliance concerns, we therefore present relevant discussion and offer perspectives on the development of next-generation sclerostin inhibitors by following several ways, such as concomitant medication, artificial intelligence-based strategy, druggable modification, and bispecific inhibitors strategy.
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Carpenter KA, Davison R, Shakthivel S, Anderson KD, Ko FC, Ross RD. Sclerostin antibody improves phosphate metabolism hormones, bone formation rates, and bone mass in adult Hyp mice. Bone 2022; 154:116201. [PMID: 34537437 PMCID: PMC8671249 DOI: 10.1016/j.bone.2021.116201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/12/2021] [Accepted: 09/13/2021] [Indexed: 01/03/2023]
Abstract
X-linked hypophosphatemia (XLH) is caused by a loss-of-function mutation in the phosphate regulating gene with homology to endopeptidase located on the X chromosome (PHEX). Loss of functional PHEX results in elevated fibroblast growth factor 23 (FGF23), impaired phosphate reabsorption, and inhibited skeletal mineralization. Sclerostin, a protein produced primarily by osteocytes, suppresses bone formation by antagonizing canonical Wnt-signaling and is reported to be elevated in XLH patients. Our previous study reported that a monoclonal antibody to sclerostin (Scl-Ab) decreases FGF23 and increases phosphate and bone mass in growing Hyp mice (XLH murine model). In the current study, we investigated the efficacy of Scl-Ab in treating XLH pathophysiology in adult Hyp mice that are past the period of rapid skeletal growth (12 and 20-weeks old). We hypothesized that Scl-Ab would not only increase bone formation, bone strength and bone mass, but would also normalize phosphate regulating hormones, FGF23, parathyroid hormone (PTH), and vitamin 1,25(OH)2D. Scl-Ab treatment increased cortical area, trabecular bone volume fraction, trabecular bone formation rate, and the bending moment in both sexes of both age groups. Scl-Ab treatment suppressed circulating levels of intact FGF23 and c-term FGF23 in treated male and female wild-type and Hyp mice of both age groups and improved both vitamin 1,25(OH)2D and PTH. Scl-Ab treated Hyp mice also showed evidence of increased renal expression of the sodium-phosphate co-transporter, NPT2a, specifically in the female Hyp mice. Our study suggests that Scl-Ab treatment can improve several skeletal and metabolic pathologies associated with XLH, further establishes the role of sclerostin in the regulation of FGF23 and provides evidence that Scl-Ab can improve phosphate regulation by targeting the bone-renal axis.
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Affiliation(s)
- Kelsey A Carpenter
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Reid Davison
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Shruti Shakthivel
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Kyle D Anderson
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Frank C Ko
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America; Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, United States of America
| | - Ryan D Ross
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America; Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, United States of America.
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Ni X, Zhang Q, Li X, Pang Q, Gong Y, Wang O, Li M, Xing X, Jiang Y, Xia W. Low Levels of Serum Sclerostin in Adult Patients With Tumor-Induced Osteomalacia Compared With X-linked Hypophosphatemia. J Clin Endocrinol Metab 2022; 107:e361-e371. [PMID: 34363479 DOI: 10.1210/clinem/dgab579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Indexed: 12/24/2022]
Abstract
CONTEXT Sclerostin inhibits Wnt-β-catenin signaling, regulating bone formation. Circulating sclerostin was reported to be elevated in X-linked hypophosphatemia (XLH) patients, and sclerostin antibody (Scl-Ab) increased bone mass and normalized circulating phosphate in Hyp mice. However, circulating sclerostin levels in patients with acquired hypophosphatemia due to tumor-induced osteomalacia (TIO) are rarely reported. OBJECTIVE This study was designed to evaluate serum sclerostin levels in TIO patients compared with age- and sex-matched healthy controls and XLH patients to analyze correlations with bone mineral density (BMD) and laboratory parameters. METHODS This cross-sectional study determined serum sclerostin levels in 190 individuals, comprising 83 adult TIO patients, 83 adult healthy controls and 24 adult XLH patients. RESULTS TIO patients (43 male, 40 female) aged 44.3 ± 8.7 (mean ± SD) years had lower levels of circulating sclerostin than controls (94.2 ± 45.8 vs 108.4 ± 42.3 pg/mL, P = 0.01), adjusted for age, gender, BMI, and diabetes rate. Sclerostin levels were positively associated with age (r = 0.238, P = 0.030). Male patients had higher sclerostin than female patients (104.7 ± 47.3 vs 83.0 ± 41.8 pg/mL, P = 0.014). Sclerostin levels were positively associated with L1-4 BMD (r = 0.255, P = 0.028), femoral neck BMD (r = 0.242, P = 0.039), and serum calcium (r = 0.231, P = 0.043). Comparison of sclerostin levels in TIO patients (n = 24, age 35.9 ± 7.3 years) vs XLH patients vs healthy controls revealed significant differences (respectively, 68.4 ± 31.3, 132.0 ± 68.8, and 98.6 ± 41.1 pg/mL, P < 0.001). CONCLUSION Circulating sclerostin was decreased in TIO patients but increased in XLH patients, possibly due to histological abnormality and bone mass.
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Affiliation(s)
- Xiaolin Ni
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Qi Zhang
- Laboratory Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiang Li
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Qianqian Pang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yiyi Gong
- Central Research Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Ou Wang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Mei Li
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiaoping Xing
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
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Ito N, Prideaux M, Wijenayaka AR, Yang D, Ormsby RT, Bonewald LF, Atkins GJ. Sclerostin Directly Stimulates Osteocyte Synthesis of Fibroblast Growth Factor-23. Calcif Tissue Int 2021; 109:66-76. [PMID: 33616712 DOI: 10.1007/s00223-021-00823-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/05/2021] [Indexed: 12/16/2022]
Abstract
Osteocyte produced fibroblast growth factor 23 (FGF23) is the key regulator of serum phosphate (Pi) homeostasis. The interplay between parathyroid hormone (PTH), FGF23 and other proteins that regulate FGF23 production and serum Pi levels is complex and incompletely characterised. Evidence suggests that the protein product of the SOST gene, sclerostin (SCL), also a PTH target and also produced by osteocytes, plays a role in FGF23 expression, however the mechanism for this effect is unclear. Part of the problem of understanding the interplay of these mediators is the complex multi-organ system that achieves Pi homeostasis in vivo. In the current study, we sought to address this using a cell line model of the osteocyte, IDG-SW3, known to express FGF23 at both the mRNA and protein levels. In cultures of differentiated IDG-SW3 cells, both PTH1-34 and recombinant human (rh) SCL remarkably induced Fgf23 mRNA expression dose-dependently within 3 h. Both rhPTH1-34 and rhSCL also strongly induced C-terminal FGF23 protein secretion. Secreted intact FGF23 levels remained unchanged, consistent with constitutive post-translational cleavage of FGF23 in this cell model. Both rhPTH1-34 and rhSCL treatments significantly suppressed mRNA levels of Phex, Dmp1 and Enpp1 mRNA, encoding putative negative regulators of FGF23 levels, and induced Galnt3 mRNA expression, encoding N-acetylgalactosaminyl-transferase 3 (GalNAc-T3), which protects FGF23 from furin-like proprotein convertase-mediated cleavage. The effect of both rhPTH1-34 and rhSCL was antagonised by pre-treatment with the NF-κβ signalling inhibitors, BAY11 and TPCK. RhSCL also stimulated FGF23 mRNA expression in ex vivo cultures of human bone. These findings provide evidence for the direct regulation of FGF23 expression by sclerostin. Locally expressed sclerostin via the induction of FGF23 in osteocytes thus has the potential to contribute to the regulation of Pi homeostasis.
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Affiliation(s)
- Nobuaki Ito
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Matthew Prideaux
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
- School of Medicine, Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Asiri R Wijenayaka
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Dongqing Yang
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Renee T Ormsby
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
- Brigham and Women's Hospital, Boston, MA, USA
| | - Lynda F Bonewald
- School of Medicine, Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Gerald J Atkins
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia.
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Osteoporosis Treatment with Anti-Sclerostin Antibodies-Mechanisms of Action and Clinical Application. J Clin Med 2021; 10:jcm10040787. [PMID: 33669283 PMCID: PMC7920044 DOI: 10.3390/jcm10040787] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/30/2021] [Accepted: 02/13/2021] [Indexed: 12/13/2022] Open
Abstract
Osteoporosis is characterized by reduced bone mass and disruption of bone architecture, resulting in increased risk of fragility fractures and significant long-term disability. Although both anti-resorptive treatments and osteoanabolic drugs, such as parathyroid hormone analogues, are effective in fracture prevention, limitations exist due to lack of compliance or contraindications to these drugs. Thus, there is a need for novel potent therapies, especially for patients at high fracture risk. Romosozumab is a monoclonal antibody against sclerostin with a dual mode of action. It enhances bone formation and simultaneously suppresses bone resorption, resulting in a large anabolic window. In this opinion-based narrative review, we highlight the role of sclerostin as a critical regulator of bone mass and present human diseases of sclerostin deficiency as well as preclinical models of genetically modified sclerostin expression, which led to the development of anti-sclerostin antibodies. We review clinical studies of romosozumab in terms of bone mass accrual and anti-fracture activity in the setting of postmenopausal and male osteoporosis, present sequential treatment regimens, and discuss its safety profile and possible limitations in its use. Moreover, an outlook comprising future translational applications of anti-sclerostin antibodies in diseases other than osteoporosis is given, highlighting the clinical significance and future scopes of Wnt signaling in these settings.
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Farrell M, Fairfield H, Costa S, D'Amico A, Falank C, Brooks DJ, Reagan MR. Sclerostin-Neutralizing Antibody Treatment Rescues Negative Effects of Rosiglitazone on Mouse Bone Parameters. J Bone Miner Res 2021; 36:158-169. [PMID: 32845528 PMCID: PMC8080259 DOI: 10.1002/jbmr.4170] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 08/14/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022]
Abstract
Obesity, a growing pandemic, is a risk factor for many cancers and causes increased bone marrow adipose tissue (BMAT). in vitro studies and obese animal models suggest that BMAT contributes to cancer progression, but there is a lack of preclinical models to directly test BMAT's role in cancer. Overactivation of peroxisome-proliferator-activated receptor-γ (PPARγ) can skew bone formation and resorption rates, resulting in increased BMAT and trabecular bone loss. Thiazolidinediones (eg, rosiglitazone) are anti-diabetic therapies that promote adipogenesis through PPARγ activation. We investigated if rosiglitazone increases BMAT in an immunocompromised model, commonly used in cancer research, and if these effects could be reversed by co-administering a bone anabolic agent (sclerostin-neutralizing antibody [Scl-Ab]), which has been shown to inhibit adipogenesis, using DXA, μCT, OsO4 μCT, and dynamic histomorphometry. Four weeks of rosiglitazone in female SCID Beige mice (cohort 1) significantly decreased trabecular bone volume (BV/TV) by about one-half, through increased osteoclast and suppressed osteoblast activity, and significantly increased BMAT. In cohort 2, mice were administered rosiglitazone ± Scl-Ab for 4 weeks, and then rosiglitazone was discontinued and Scl-Ab or vehicle were continued for 6 weeks. Scl-Ab significantly increased bone parameters (eg, BV/TV, N.Ob/B.Pm, and MS/BS) in both groups. Scl-Ab also overcame many negative effects of rosiglitazone (eg, effects on trabecular bone parameters, increased mineralization lag time [MLT], and decreased bone formation rate [BFR]). Interestingly, Scl-Ab significantly decreased rosiglitazone-induced BMAT in the femur, mostly due to a reduction in adipocyte size, but had a much weaker effect on tibial BMAT. These data suggest targeting sclerostin can prevent rosiglitazone-induced bone loss and reduce BM adiposity, in some, but not all BMAT locations. Collectively, our data demonstrate that rosiglitazone increases BMAT in SCID Beige mice, but concomitant changes in bone may confound its use to specifically determine BMAT's role in tumor models. © 2020 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Mariah Farrell
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Biology Department, University of Southern Maine, Portland, ME, USA
| | - Heather Fairfield
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Tufts University School of Medicine, Boston, MA, USA
| | - Samantha Costa
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Anastasia D'Amico
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Biology Department, University of Southern Maine, Portland, ME, USA
| | - Carolyne Falank
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA
| | - Daniel J Brooks
- Center for Skeletal Research, Massachusetts General Hospital, Boston, MA, USA
| | - Michaela R Reagan
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Biology Department, University of Southern Maine, Portland, ME, USA.,Tufts University School of Medicine, Boston, MA, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
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10
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Ni X, Li X, Zhang Q, Liu C, Gong Y, Wang O, Li M, Xing X, Jiang Y, Xia W. Clinical Characteristics and Bone Features of Autosomal Recessive Hypophosphatemic Rickets Type 1 in Three Chinese Families: Report of Five Chinese Cases and Review of the Literature. Calcif Tissue Int 2020; 107:636-648. [PMID: 32920683 DOI: 10.1007/s00223-020-00755-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 09/02/2020] [Indexed: 12/15/2022]
Abstract
Autosomal recessive hypophosphatemic rickets type 1 (ARHR1) was reported to be caused by homozygous mutation of dentin matrix protein 1 (DMP1). To date, very few cases have been reported. Here, we summarized clinical, laboratory and imaging findings of ARHR1 patients in our hospital. Literature review was performed to analyze genotype-phenotype correlation. Five Chinese patients from three unrelated pedigrees presented with lower extremity deformity and short stature. Hypophosphatemia, elevated alkaline phosphatase, high intact fibroblast growth factor 23 and sclerostin were found. X-ray uncovered coexistence of osteomalacia and osteosclerosis. Although areal bone mineral density (aBMD) of axial bone measured by dual-energy X-ray absorptiometry was relatively high in all patients, volumetric BMD (vBMD) and microstructure of one adult patient's peripheral bone detected by HR-pQCT were damaged. Mutation analyses of DMP1 revealed three homozygous mutations including two novel mutations, c.54 + 1G > C and c.94C > A (p.E32X), and a reported mutation c.184-1G > A. Genotype-phenotype correlation analysis including 30 cases (25 from literature review and 5 from our study) revealed that patients harboring mutations affecting C-terminal fragment of DMP1 presented with shorter stature (Z score of height = - 3.4 ± 1.6 vs - 1.0 ± 1.6, p = 0.001) and lower serum phosphate level (0.70 ± 0.15 vs 0.84 ± 0.16, p = 0.03) than those harboring mutations only affecting N-terminal fragment. In summary, we reported five Chinese ARHR1 patients and identified two novel DMP1 mutations. High aBMD and local osteosclerosis in axial bone with low vBMD and damaged microstructure in peripheral bone were featured. Genotype-phenotype correlation analysis confirmed the important role of C-terminal fragment of DMP1.
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Affiliation(s)
- Xiaolin Ni
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Xiang Li
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Qi Zhang
- Laboratory Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Chang Liu
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Yiyi Gong
- Central Research Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Ou Wang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Mei Li
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Xiaoping Xing
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China.
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China.
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11
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Carpenter KA, Ross RD. Sclerostin Antibody Treatment Increases Bone Mass and Normalizes Circulating Phosphate Levels in Growing Hyp Mice. J Bone Miner Res 2020; 35:596-607. [PMID: 31743490 PMCID: PMC7370944 DOI: 10.1002/jbmr.3923] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 02/06/2023]
Abstract
X-linked hypophosphatemia (XLH), caused by a loss-of-function mutation in the phosphate regulating gene with homology to endopeptidase located on the X chromosome (PHEX), is the most common form of vitamin D-resistant rickets. Loss of functional PHEX results in elevated fibroblast growth factor 23 (FGF23) levels, impaired phosphate reabsorption, and inhibited skeletal mineralization. Sclerostin, a protein produced primarily in osteocytes, suppresses bone formation by antagonizing Wnt signaling and is reported to be elevated in XLH patients. This study used the Hyp mouse model to investigate sclerostin's role in the pathophysiology of XLH by evaluating the use of a monoclonal antibody to sclerostin in a mouse model of XLH, the Hyp mouse. Male and female wild-type and Hyp littermates were injected with 25 mg/kg of vehicle or sclerostin antibody (Scl-Ab) twice weekly, beginning at 4 weeks of age and euthanized at 8 weeks of age. Scl-Ab treatment increased serum phosphate levels and suppressed circulating levels of intact FGF23 in treated wild-type and Hyp mice of both sexes. Cortical area, trabecular bone volume fraction (BV/TV), metaphyseal apparent density, and the peak load increased with Scl-Ab treatment in both sexes. This short-term treatment study suggests that Scl-Ab treatment can effectively improve some of the pathologies associated with XLH, including normalization of phosphate, and that sclerostin may play a role in regulating FGF23 and phosphate metabolism in XLH. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Kelsey A Carpenter
- Department of Cell and Molecular Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Ryan D Ross
- Department of Cell and Molecular Medicine, Rush University Medical Center, Chicago, IL, USA.,Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
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12
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Pereira RC, Salusky IB, Roschger P, Klaushofer K, Yadin O, Freymiller EG, Bowen R, Delany AM, Fratzl-Zelman N, Wesseling-Perry K. Impaired osteocyte maturation in the pathogenesis of renal osteodystrophy. Kidney Int 2019; 94:1002-1012. [PMID: 30348285 DOI: 10.1016/j.kint.2018.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/18/2018] [Accepted: 08/09/2018] [Indexed: 12/18/2022]
Abstract
Pediatric renal osteodystrophy is characterized by skeletal mineralization defects, but the role of osteoblast and osteocyte maturation in the pathogenesis of these defects is unknown. We evaluated markers of osteocyte maturation and programmed cell death in iliac crest biopsy samples from pediatric dialysis patients and healthy controls. We evaluated the relationship between numbers of fibroblast growth factor 23 (FGF23)-expressing osteocytes and histomorphometric parameters of skeletal mineralization. We confirmed that chronic kidney disease (CKD) causes intrinsic changes in bone cell maturation using an in vitro model of primary osteoblasts from patients with CKD and healthy controls. FGF23 co-localized with the early osteocyte marker E11/gp38, suggesting that FGF23 is a marker of early osteocyte maturation. Increased numbers of early osteocytes and decreased osteocyte apoptosis characterized CKD bone. Numbers of FGF23-expressing osteocytes were highest in patients with preserved skeletal mineralization indices, and packets of matrix surrounding FGF23-expressing osteocytes appeared to have entered secondary mineralization. Primary osteoblasts from patients with CKD retained impaired maturation and mineralization characteristics in vitro. Addition of FGF23 did not affect primary osteoblast mineralization. Thus, CKD is associated with intrinsic changes in osteoblast and osteocyte maturation, and FGF23 appears to mark a relatively early stage in osteocyte maturation. Improved control of renal osteodystrophy and FGF23 excess will require further investigation into the pathogenesis of CKD-mediated osteoblast and osteocyte maturation failure.
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Affiliation(s)
- Renata C Pereira
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Isidro B Salusky
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Paul Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGK and AUVA Trauma Centre Meidling, 1(st) Medical Department, Hanusch Hospital, Vienna, Austria
| | - Klaus Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGK and AUVA Trauma Centre Meidling, 1(st) Medical Department, Hanusch Hospital, Vienna, Austria
| | - Ora Yadin
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | | | - Richard Bowen
- Department of Orthopedics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Anne M Delany
- Center for Molecular Oncology, UConn Health, Farmington, Connecticut, USA
| | - Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGK and AUVA Trauma Centre Meidling, 1(st) Medical Department, Hanusch Hospital, Vienna, Austria
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13
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Brommage R, Ohlsson C. High Fidelity of Mouse Models Mimicking Human Genetic Skeletal Disorders. Front Endocrinol (Lausanne) 2019; 10:934. [PMID: 32117046 PMCID: PMC7010808 DOI: 10.3389/fendo.2019.00934] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 12/23/2019] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED The 2019 International Skeletal Dysplasia Society nosology update lists 441 genes for which mutations result in rare human skeletal disorders. These genes code for enzymes (33%), scaffolding proteins (18%), signal transduction proteins (16%), transcription factors (14%), cilia proteins (8%), extracellular matrix proteins (5%), and membrane transporters (4%). Skeletal disorders include aggrecanopathies, channelopathies, ciliopathies, cohesinopathies, laminopathies, linkeropathies, lysosomal storage diseases, protein-folding and RNA splicing defects, and ribosomopathies. With the goal of evaluating the ability of mouse models to mimic these human genetic skeletal disorders, a PubMed literature search identified 260 genes for which mutant mice were examined for skeletal phenotypes. These mouse models included spontaneous and ENU-induced mutants, global and conditional gene knockouts, and transgenic mice with gene over-expression or specific base-pair substitutions. The human X-linked gene ARSE and small nuclear RNA U4ATAC, a component of the minor spliceosome, do not have mouse homologs. Mouse skeletal phenotypes mimicking human skeletal disorders were observed in 249 of the 260 genes (96%) for which comparisons are possible. A supplemental table in spreadsheet format provides PubMed weblinks to representative publications of mutant mouse skeletal phenotypes. Mutations in 11 mouse genes (Ccn6, Cyp2r1, Flna, Galns, Gna13, Lemd3, Manba, Mnx1, Nsd1, Plod1, Smarcal1) do not result in similar skeletal phenotypes observed with mutations of the homologous human genes. These discrepancies can result from failure of mouse models to mimic the exact human gene mutations. There are no obvious commonalities among these 11 genes. Body BMD and/or radiologic dysmorphology phenotypes were successfully identified for 28 genes by the International Mouse Phenotyping Consortium (IMPC). Forward genetics using ENU mouse mutagenesis successfully identified 37 nosology gene phenotypes. Since many human genetic disorders involve hypomorphic, gain-of-function, dominant-negative and intronic mutations, future studies will undoubtedly utilize CRISPR/Cas9 technology to examine transgenic mice having genes modified to exactly mimic variant human sequences. Mutant mice will increasingly be employed for drug development studies designed to treat human genetic skeletal disorders. SIGNIFICANCE Great progress is being made identifying mutant genes responsible for human rare genetic skeletal disorders and mouse models for genes affecting bone mass, architecture, mineralization and strength. This review organizes data for 441 human genetic bone disorders with regard to heredity, gene function, molecular pathways, and fidelity of relevant mouse models to mimic the human skeletal disorders. PubMed weblinks to citations of 249 successful mouse models are provided.
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Affiliation(s)
- Robert Brommage
- Department of Internal Medicine and Clinical Nutrition, Centre for Bone and Arthritis Research, Institute of Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- *Correspondence: Robert Brommage
| | - Claes Ohlsson
- Department of Internal Medicine and Clinical Nutrition, Centre for Bone and Arthritis Research, Institute of Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- Department of Drug Treatment, Sahlgrenska University Hospital, Gothenburg, Sweden
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14
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Bisson SK, Ung RV, Mac-Way F. Role of the Wnt/ β-Catenin Pathway in Renal Osteodystrophy. Int J Endocrinol 2018; 2018:5893514. [PMID: 29808090 PMCID: PMC5901476 DOI: 10.1155/2018/5893514] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/08/2018] [Indexed: 12/17/2022] Open
Abstract
Vascular calcification and bone fragility are common and interrelated health problems that affect chronic kidney disease (CKD) patients. Bone fragility, which leads to higher risk of fracture and mortality, arises from the abnormal bone remodeling and mineralization that are seen in chronic kidney disease. Recently, sclerostin and Dickkopf-related protein 1 were suggested to play a significant role in CKD-related bone disease as they are known inhibitors of the Wnt pathway, thus preventing bone formation. This review focuses on new knowledge about the Wnt pathway in bone, how its function is affected by chronic kidney disease and how this affects bone structure. Expression of components and inhibitors of the Wnt pathway has been shown to be affected by the loss of kidney function, and a better understanding of the bone effects of Wnt pathway inhibitors could allow the development of new therapies to prevent bone fragility in this population.
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Affiliation(s)
- Sarah-Kim Bisson
- Faculty and Department of Medicine, CHU de Québec Research Center, L'Hôtel-Dieu de Québec Hospital, Endocrinology and Nephrology Axis, Université Laval, Quebec, Canada
| | - Roth-Visal Ung
- Faculty and Department of Medicine, CHU de Québec Research Center, L'Hôtel-Dieu de Québec Hospital, Endocrinology and Nephrology Axis, Université Laval, Quebec, Canada
| | - Fabrice Mac-Way
- Faculty and Department of Medicine, CHU de Québec Research Center, L'Hôtel-Dieu de Québec Hospital, Endocrinology and Nephrology Axis, Université Laval, Quebec, Canada
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15
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Wesseling-Perry K, Mäkitie RE, Välimäki VV, Laine T, Laine CM, Välimäki MJ, Pereira RC, Mäkitie O. Osteocyte Protein Expression Is Altered in Low-Turnover Osteoporosis Caused by Mutations in WNT1 and PLS3. J Clin Endocrinol Metab 2017; 102:2340-2348. [PMID: 28379384 PMCID: PMC5505188 DOI: 10.1210/jc.2017-00099] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/29/2017] [Indexed: 01/20/2023]
Abstract
CONTEXT Osteocytes express proteins that regulate bone remodeling and mineralization. OBJECTIVE To evaluate the relationship between osteocyte-specific protein expression and bone histology in patients with monogenic osteoporosis due to wingless integration site 1 (WNT1) or plastin 3 (PLS3) mutations. DESIGN AND SETTING Cross-sectional cohort study at a university hospital. PARTICIPANTS Six patients (four males; ages: 14 to 72 years) with a heterozygous WNT1 mutation and five patients (four males; ages: 9 to 70 years) with a heterozygous/hemizygous PLS3 mutation. METHODS AND MAIN OUTCOME MEASURES Immunohistochemistry was performed for fibroblast growth factor 23 (FGF23), dentin matrix protein 1 (DMP1), sclerostin, and phosphorylated (phospho-)β-catenin in iliac crest samples and compared with bone histomorphometry. RESULTS FGF23 expression in WNT1 patients was 243% that observed in PLS3 patients (P < 0.01). DMP1, sclerostin, and phospho-β-catenin expression did not differ between groups. Serum phosphate correlated inversely with FGF23 expression (r = -0.79, P = 0.01) and serum ionized calcium correlated inversely with sclerostin expression (r = -0.60, P = 0.05). Phospho-β-catenin expression correlated inversely with DMP1 expression (r = -0.88, P < 0.001), osteoid volume/bone volume (r = -0.68, P = 0.02), and bone formation rate (r = -0.78, P < 0.01). FGF23 expression did not correlate with DMP1 expression, sclerostin expression, or bone histomorphometry. Marrow adiposity was higher in WNT1 than in PLS3 patients (P = 0.04). CONCLUSIONS Mutations that disrupt WNT signaling and osteocytic mechanosensing affect osteocyte protein expression. Abnormal osteocyte function may play a role in the pathogenesis of monogenetic forms of osteoporosis.
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Affiliation(s)
- Katherine Wesseling-Perry
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Riikka E. Mäkitie
- Folkhälsan Institute of Genetics, University of Helsinki, 00014 Helsinki, Finland
| | - Ville-Valtteri Välimäki
- Department of Orthopedics and Traumatology, Helsinki University Central Hospital and Helsinki University, Jorvi Hospital, 02740 Espoo, Finland
| | - Tero Laine
- Department of Orthopedics, Institute of Clinical Sciences, Sahlgrenska University Hospital and University of Gothenburg, 41345 Gothenburg, Sweden
| | - Christine M. Laine
- Children’s Hospital, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
- Department of Endocrinology, Institute of Medicine, Sahlgrenska University Hospital and University of Gothenburg, 41345 Gothenburg, Sweden
| | - Matti J. Välimäki
- Division of Endocrinology, Department of Medicine, Helsinki University Central Hospital, 00029 Helsinki, Finland
| | - Renata C. Pereira
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 17176 Stockholm, Sweden
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16
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Fratzl-Zelman N, Valta H, Pereira RC, Misof BM, Roschger P, Jalanko H, Wesseling-Perry K, Klaushofer K, Mäkitie O. Abnormally High and Heterogeneous Bone Matrix Mineralization After Childhood Solid Organ Transplantation: A Complex Pathology of Low Bone Turnover and Local Defects in Mineralization. J Bone Miner Res 2017; 32:1116-1125. [PMID: 28214296 DOI: 10.1002/jbmr.3087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/18/2017] [Accepted: 01/20/2017] [Indexed: 01/20/2023]
Abstract
Chronic renal, liver, and heart failure in children associates with multiple skeletal complications. Increased fracture incidence often persists after transplantation and could be related to alterations in bone material properties. In the present cohort study we evaluated bone mineralization density distribution (BMDD) by quantitative backscattered electron imaging (qBEI) in 23 pediatric solid organ allograft recipients with suspected osteoporosis. We measured BMDD in the entire cross-sectional area of transiliac bone biopsies obtained from kidney (n = 9), liver (n = 9), and heart (n = 5) transplant recipients (aged 7.6 to 19.7 years; 6.0 ± 5.6 years posttransplantation, patients with a history of clinical fractures: n = 14). The BMDD findings were compared with age-appropriate references and with a previously presented cohort of children with chronic kidney disease on dialysis (CKD5D, n = 18). Furthermore, we related the BMDD parameters with patients' clinical and bone histomorphometric outcomes. Compared to healthy children, qBEI results for cancellous and cortical bone in transplant recipients revealed an increase in the most frequently occurring calcium concentration (+2.9%, p = 0.001; +3.5%, p = 0.014), in the portion of fully mineralized bone (fivefold; 10-fold, both p < 0.0001) and in heterogeneity of mineralization (+26,5% and +27.8%, both p < 0.0001), respectively. Moreover, the BMDD parameters were nonsignificantly distinct from CKD5D cohort except that the heterogeneity in mineralization was higher posttransplantation. There was a strong inverse correlation between the average calcium content of the bone matrix and patients' biochemical ALP levels, histomorphometric indices of bone formation and resorption. The abnormally high bone matrix mineralization in transplant recipients, consistent with serum and histomorphometric outcomes, suggests a history of low bone turnover with accumulation of fully mineralized bone packets. Additionally, the increased heterogeneity of mineralization suggests local alterations in mineralization kinetics, which may be linked to dysfunctional osteocytes that were recently shown to accumulate within the bone matrix during organ failure and concomitant glucocorticoid and immunosuppressive medication. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre, Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - Helena Valta
- Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Renata C Pereira
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Barbara M Misof
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre, Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - Paul Roschger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre, Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - Hannu Jalanko
- Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | | | - Klaus Klaushofer
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre, Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - Outi Mäkitie
- Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland.,Folkhälsan Research Center, Helsinki, Finland.,Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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17
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Ominsky MS, Boyce RW, Li X, Ke HZ. Effects of sclerostin antibodies in animal models of osteoporosis. Bone 2017; 96:63-75. [PMID: 27789417 DOI: 10.1016/j.bone.2016.10.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 10/14/2016] [Accepted: 10/20/2016] [Indexed: 10/20/2022]
Abstract
There is an unmet need for therapies that can restore bone strength and reduce fracture risk among patients at high risk of osteoporotic fracture. To address this need, bone-forming therapies that increase osteoblast activity are required to help restore bone structure and strength. Sclerostin is now recognized as a target for osteoporosis therapy. Sclerostin is predominantly secreted by the osteocyte and acts as an extracellular inhibitor of canonical Wnt signaling by binding to the receptors lipoprotein receptor-related protein-4, 5 and 6. Monoclonal antibodies to sclerostin (Scl-Ab) have been used in both clinical and in preclinical studies of osteoporosis with beneficial outcomes for bone density, structure, strength and fracture risk reduction. In this review paper, we summarize the current literature describing the effects of Scl-Ab in animal models of osteoporosis. In addition, we report new pharmacologic data from three animal studies of Scl-Ab: 1) a 12-month study evaluating bone quality in ovariectomized (OVX) rats; 2) a 6-month study evaluating bone structure and strength in adolescent cynomolgus monkeys; and 3) the effects of transition from Scl-Ab to vehicle or the RANKL inhibitor osteoprotegerin-Fc in OVX rats. Together, these results demonstrate that inhibition of sclerostin by Scl-Ab increased bone formation, and decreased bone resorption, leading to improved bone structure, bone mass and bone strength while maintaining bone quality in multiple animal models of osteoporosis. Further, gains in bone mass induced by Scl-Ab treatment were preserved by antiresorptive agents such as a RANKL inhibitor as a follow-on therapy. The bone-forming effects of Scl-Ab were unaffected by pre- or co-treatment with a bisphosphonate, and were restored following a treatment-free period after initial dosing. These data support the clinical development of Scl-Ab for treatment of conditions with low bone mass such as postmenopausal and male osteoporosis.
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Affiliation(s)
| | | | - Xiaodong Li
- Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320-1799, USA.
| | - Hua Zhu Ke
- UCB Pharma, 208 Bath Road, Slough, Berkshire SL1 3WE, UK.
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18
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Jacobsen CM. Application of anti-Sclerostin therapy in non-osteoporosis disease models. Bone 2017; 96:18-23. [PMID: 27780792 PMCID: PMC5328800 DOI: 10.1016/j.bone.2016.10.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/17/2016] [Accepted: 10/20/2016] [Indexed: 12/29/2022]
Abstract
Sclerostin, a known inhibitor of the low density lipoprotein related protein 5 and 6 (LRP5 and LRP6) cell surface signaling receptors, is integral in the maintenance of normal bone mass and strength. Patients with loss of function mutations in SOST or missense mutations in LRP5 that prevent Sclerostin from binding and inhibiting the receptor, have significantly increased bone mass. This observation leads to the development of Sclerostin neutralizing therapies to increase bone mass and strength. Anti-Sclerostin therapy has been shown to be effective at increasing bone density and strength in animal models and patients with osteoporosis. Loss of function of Sost or treatment with a Sclerostin neutralizing antibody improves bone properties in animal models of Osteoporosis Pseudoglioma syndrome (OPPG), likely due to action through the LRP6 receptor, which suggests patients may benefit from these therapies. Sclerostin antibody is effective at improving bone properties in mouse models of Osteogenesis Imperfecta, a genetic disorder of low bone mass and fragility due to type I collagen mutations, in as little as two weeks after initiation of therapy. However, these improvements are due to increases in bone quantity as the quality (brittleness) of bone remains unaffected. Similarly, Sclerostin antibody treatment improves bone density in animal models of other diseases. Sclerostin neutralizing therapies are likely to benefit many patients with genetic disorders of bone, as well as other forms of metabolic bone disease.
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Affiliation(s)
- Christina M Jacobsen
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA, United States; Division of Endocrinology, Boston Children's Hospital, Boston, MA, United States; Division of Genetics, Boston Children's Hospital, Boston, MA, United States; Department of Pediatrics, Harvard Medical School, Boston, MA, United States.
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19
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Wang J, Massoudi D, Ren Y, Muir AM, Harris SE, Greenspan DS, Feng JQ. BMP1 and TLL1 Are Required for Maintaining Periodontal Homeostasis. J Dent Res 2017; 96:578-585. [PMID: 28068493 DOI: 10.1177/0022034516686558] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mutations in bone morphogenetic protein 1 (BMP1) in humans or deletion of BMP1 and related protease tolloid like 1 (TLL1) in mice lead to osteogenesis imperfecta (OI). Here, we show progressive periodontal defects in mice in which both BMP1 and TLL1 have been conditionally ablated, including malformed periodontal ligament (PDL) (recently shown to play key roles in normal alveolar bone formation), significant loss in alveolar bone mass ( P < 0.01), and a sharp reduction in cellular cementum. Molecular mechanism studies revealed a dramatic increase in the uncleaved precursor of type I collagen (procollagen I) and a reduction in dentin matrix protein 1 (DMP1), which is partially responsible for defects in extracellular matrix (ECM) formation and mineralization. We also showed a marked increase in the expression of matrix metallopeptidase 13 (MMP13) and tartrate-resistant acid phosphatase (TRAP), leading to an acceleration in periodontal breakdown. Finally, we demonstrated that systemic application of antibiotics significantly improved the alveolar bone and PDL damage of the knockdown phenotype, which are thus shown to be partially secondary to pathogen-induced inflammation. Together, identification of the novel roles of BMP1 and TLL1 in maintaining homeostasis of periodontal formation, partly via biosynthetic processing of procollagen I and DMP1, provides novel insights into key contributions of the extracellular matrix environment to periodontal homeostasis and contributes toward understanding of the pathology of periodontitis.
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Affiliation(s)
- J Wang
- 1 Biomedical Sciences, Texas A&M College of Dentistry, Dallas, TX, USA.,2 State Key Laboratory of Oral Diseases, Department of Periodontics, West China Hospital of Stomatology, Sichuan University, China
| | - D Massoudi
- 3 Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Y Ren
- 1 Biomedical Sciences, Texas A&M College of Dentistry, Dallas, TX, USA
| | - A M Muir
- 3 Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - S E Harris
- 4 Department of Periodontics, UT Health Science Center School of Dentistry, San Antonio, TX, USA
| | - D S Greenspan
- 3 Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - J Q Feng
- 1 Biomedical Sciences, Texas A&M College of Dentistry, Dallas, TX, USA
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20
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Abstract
Osteocytes are differentiated osteoblasts that become surrounded by matrix during the process of bone formation. Acquisition of the osteocyte phenotype is achieved by profound changes in gene expression that facilitate adaptation to the changing cellular environment and constitute the molecular signature of osteocytes. During osteocytogenesis, the expression of genes that are characteristic of the osteoblast are altered and the expression of genes and/or proteins that impart dendritic cellular morphology, regulate matrix mineralization and control the function of cells at the bone surface are ordely modulated. The discovery of mutations in human osteocytic genes has contributed, in a large part, to our understanding of the role of osteocytes in bone homeostasis. Osteocytes are targets of the mechanical force imposed on the skeleton and have a critical role in integrating mechanosensory pathways with the action of hormones, which thereby leads to the orchestrated response of bone to environmental cues. Current, therapeutic approaches harness this accumulating knowledge by targeting osteocytic signalling pathways and messengers to improve skeletal health.
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Affiliation(s)
- Lilian I. Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine
- Roudebush Veterans Administration Medical Center, Indianapolis, IN
| | - Teresita Bellido
- Department of Anatomy and Cell Biology, Indiana University School of Medicine
- Department of Medicine, Division of Endocrinology, Indiana University School of Medicine
- Roudebush Veterans Administration Medical Center, Indianapolis, IN
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