1
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O’Donohue AK, Li XC, Lee LR, Vasiljevski ER, Little DG, Munns CF, Schindeler A. Dietary intervention rescues a bone porosity phenotype in a murine model of Neurofibromatosis Type 1 (NF1). PLoS One 2024; 19:e0304778. [PMID: 38913608 PMCID: PMC11195983 DOI: 10.1371/journal.pone.0304778] [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: 01/07/2024] [Accepted: 05/19/2024] [Indexed: 06/26/2024] Open
Abstract
Neurofibromatosis type 1 (NF1) is a complex genetic disorder that affects a range of tissues including muscle and bone. Recent preclinical and clinical studies have shown that Nf1 deficiency in muscle causes metabolic changes resulting in intramyocellular lipid accumulation and muscle weakness. These can be subsequently rescued by dietary interventions aimed at modulating lipid availability and metabolism. It was speculated that the modified diet may rescue defects in cortical bone as NF1 deficiency has been reported to affect genes involved with lipid metabolism. Bone specimens were analyzed from wild type control mice as well as Nf1Prx1-/- (limb-targeted Nf1 knockout mice) fed standard chow versus a range of modified chows hypothesized to influence lipid metabolism. Mice were fed from 4 weeks to 12 weeks of age. MicroCT analysis was performed on the cortical bone to examine standard parameters (bone volume, tissue mineral density, cortical thickness) and specific porosity measures (closed pores corresponding to osteocyte lacunae, and larger open pores). Nf1Prx1-/- bones were found to have inferior bone properties to wild type bones, with a 4-fold increase in the porosity attributed to open pores. These measures were rescued by dietary interventions including a L-carnitine + medium-chain fatty acid supplemented chow previously shown to improve muscle histology function. Histological staining visualized these changes in bone porosity. These data support the concept that lipid metabolism may have a mechanistic impact on bone porosity and quality in NF1.
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Affiliation(s)
- Alexandra K. O’Donohue
- Bioengineering and Molecular Medicine Laboratory, The Children’s Hospital at Westmead and the Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- School of Chemical and Biomolecular Engineering, Faculty of Engineering, The University of Sydney, Sydney, New South Wales, Australia
| | - Xiaoying C. Li
- Bioengineering and Molecular Medicine Laboratory, The Children’s Hospital at Westmead and the Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Lucinda R. Lee
- Bioengineering and Molecular Medicine Laboratory, The Children’s Hospital at Westmead and the Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Emily R. Vasiljevski
- Bioengineering and Molecular Medicine Laboratory, The Children’s Hospital at Westmead and the Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - David G. Little
- Bioengineering and Molecular Medicine Laboratory, The Children’s Hospital at Westmead and the Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Craig F. Munns
- Child Health Research Centre, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
- Department of Endocrinology and Diabetes, Queensland Children’s Hospital, Brisbane, Queensland, Australia
| | - Aaron Schindeler
- Bioengineering and Molecular Medicine Laboratory, The Children’s Hospital at Westmead and the Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- School of Chemical and Biomolecular Engineering, Faculty of Engineering, The University of Sydney, Sydney, New South Wales, Australia
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2
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Kuzu TE, Öztürk K, Gürgan CA, Yay A, Göktepe Ö, Kantarcı A. Anti-inflammatory and pro-regenerative effects of a monoterpene glycoside on experimental periodontitis in a rat model of diabetes. J Periodontal Res 2023; 58:932-938. [PMID: 37340760 DOI: 10.1111/jre.13151] [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] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/17/2023] [Accepted: 06/06/2023] [Indexed: 06/22/2023]
Abstract
OBJECTIVE Paeoniflorin (Pae) is a monoterpene glycoside with immune-regulatory effects. Several studies have already demonstrated the impact of Pae on periodontitis, but its effect on diabetic periodontitis is unclear. In this study, our aim was to test the hypothesis that Pae had a strong anti-inflammatory effect that prevented bone loss in diabetic periodontitis. METHODS Thirty male Wistar albino rats were randomly divided into control (healthy, n = 10), periodontitis (PD) + diabetes (DM; n = 10), and PD + DM + Pae (n = 10) groups. Ligature-induced periodontitis was created by placing 4-0 silk ligatures around the lower first molars on both sides of the mandibulae. Experimental DM was created via an injection of 50 mg/kg and streptozotocin (STZ). Hyperglycemia was confirmed by the blood glucose levels of rats (>300 mg/dL). The bone mineral density (BMD), trabecular number, trabecular thickness, and bone loss were measured by micro-CT. The expression levels of IL-1β, IL-6, and TNF-α were measured in tissue homogenates by ELISA. RESULTS The PD + DM + Pae group had significantly less alveolar crest resorption when compared to the PD + DM group. There was also a significant difference between the PD + DM + Pae group compared to PD + DM group in trabecular thickness, BMD, and the number of trabeculae. Pae application led to a statistically significant decrease in IL-1β, IL-6, and TNF-α levels in diabetic periodontitis. CONCLUSION Systemic application of Pae suppressed inflammation caused by PD and DM, leading to reduced bone loss and enhanced bone quality.
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Affiliation(s)
- Turan Emre Kuzu
- Department of Periodontology, Faculty of Dentistry, Nuh Naci Yazgan University, Kayseri, Turkey
| | - Kübra Öztürk
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Nuh Naci Yazgan University, Kayseri, Turkey
| | - Cem A Gürgan
- Department of Periodontology, Faculty of Dentistry, Nuh Naci Yazgan University, Kayseri, Turkey
| | - Arzu Yay
- Department of Histology and Embryology, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | - Özge Göktepe
- Department of Histology and Embryology, Faculty of Medicine, Erciyes University, Kayseri, Turkey
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3
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Stevenson DA, Viscogliosi G, Leoni C. Bone health in RASopathies. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:459-470. [PMID: 36461161 DOI: 10.1002/ajmg.c.32020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/07/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022]
Abstract
The RASopathies are a group of disorders due to pathogenic variants in genes involved in the Ras/MAPK pathway, many of which have overlapping clinical features (e.g., neurofibromatosis type 1, Costello syndrome, cardiofaciocutaneous syndrome and Noonan syndrome) including musculoskeletal manifestations. Osteopenia and osteoporosis are reported in many of the RASopathies suggesting a shared pathogenesis. Even though osteopenia and osteoporosis are often detected and fractures have been reported, the clinical impact of bone mineralization defects on the skeleton of the various syndromes is poorly understood. Further knowledge of the role of the Ras/MAPK pathway on the bone cellular function, and more detailed musculoskeletal phenotyping will be critical in helping to develop therapies to improve bone health in the RASopathies.
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Affiliation(s)
- David A Stevenson
- Department of Pediatrics, Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Germana Viscogliosi
- Center for Rare Diseases and Birth Defect, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Chiara Leoni
- Center for Rare Diseases and Birth Defect, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
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4
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Ahmed R, Uppuganti S, Derasari S, Meyer J, Pennings JS, Elefteriou F, Nyman JS. Identifying Bone Matrix Impairments in a Mouse Model of Neurofibromatosis Type 1 (NF1) by Clinically Translatable Techniques. J Bone Miner Res 2022; 37:1603-1621. [PMID: 35690920 PMCID: PMC9378557 DOI: 10.1002/jbmr.4633] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/25/2022] [Accepted: 06/04/2022] [Indexed: 11/06/2022]
Abstract
Three-to-four percent of children with neurofibromatosis type 1 (NF1) present with unilateral tibia bowing, fracture, and recalcitrant healing. Alkaline phosphatase (ALP) enzyme therapy prevented poor bone mineralization and poor mechanical properties in mouse models of NF1 skeletal dysplasia; but transition to clinical trials is hampered by the lack of a technique that (i) identifies NF1 patients at risk of tibia bowing and fracture making them eligible for trial enrollment and (ii) monitors treatment effects on matrix characteristics related to bone strength. Therefore, we assessed the ability of matrix-sensitive techniques to provide characteristics that differentiate between cortical bone from mice characterized by postnatal loss of Nf1 in Osx-creTet-Off ;Nf1flox/flox osteoprogenitors (cKO) and from wild-type (WT) mice. Following euthanasia at two time points of bone disease progression, femur and tibia were harvested from both genotypes (n ≥ 8/age/sex/genotype). A reduction in the mid-diaphysis ultimate force during three-point bending at 20 weeks confirmed deleterious changes in bone induced by Nf1 deficiency, regardless of sex. Pooling females and males, low bound water (BW), and low cortical volumetric bone mineral density (Ct.vBMD) were the most accurate outcomes in distinguishing cKO from WT femurs with accuracy improving with age. Ct.vBMD and the average unloading slope (Avg-US) from cyclic reference point indentation tests were the most sensitive in differentiating WT from cKO tibias. Mineral-to-matrix ratio and carbonate substitution from Raman spectroscopy were not good classifiers. However, when combined with Ct.vBMD and BW (femur), they helped predict bending strength. Nf1 deficiency in osteoprogenitors negatively affected bone microstructure and matrix quality with deficits in properties becoming more pronounced with duration of Nf1 deficiency. Clinically measurable without ionizing radiation, BW and Avg-US are sensitive to deleterious changes in bone matrix in a preclinical model of NF1 bone dysplasia and require further clinical investigation as potential indicators of an onset of bone weakness in children with NF1. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Rafay Ahmed
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.,Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sasidhar Uppuganti
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.,Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Shrey Derasari
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Joshua Meyer
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Jacquelyn S Pennings
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.,Center for Musculoskeletal Research, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Florent Elefteriou
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Orthopaedic Surgery, Baylor College of Medicine, Houston, TX, USA
| | - Jeffry S Nyman
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.,Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.,Center for Musculoskeletal Research, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
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5
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Porrelli D, Abrami M, Pelizzo P, Formentin C, Ratti C, Turco G, Grassi M, Canton G, Grassi G, Murena L. Trabecular bone porosity and pore size distribution in osteoporotic patients - A low field nuclear magnetic resonance and microcomputed tomography investigation. J Mech Behav Biomed Mater 2021; 125:104933. [PMID: 34837800 DOI: 10.1016/j.jmbbm.2021.104933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 10/10/2021] [Accepted: 10/25/2021] [Indexed: 01/19/2023]
Abstract
The study of bone morphology is of great importance as bone morphology is influenced by factors such as age and underlying comorbidities and is associated with bone mechanical properties and fracture risk. Standard diagnostic techniques used in bone disease, such as Dual-Energy X-ray absorptiometry and ultrasonography do not provide qualitative and quantitative morphological information. In recent years, techniques such as High Resolution Computed Tomography (HR-CT), micro- CT, Magnetic Resonance Imaging (MRI), and Low Field Nuclear Magnetic Resonance (LF-NMR) have been developed for the study of bone structure and porosity. Data obtained from these techniques have been used to construct models to predict bone mechanical properties thanks to finite element analysis. Cortical porosity has been extensively studied and successfully correlated with disease progression and mechanical properties. Trabecular porosity and pore size distribution, however, have increasingly been taken into consideration to obtain a comprehensive analysis of bone pathology and mechanic. Therefore, we have decided to evaluate the ability of micro- CT (chosen for its high spatial resolving power) and LF-NMR (chosen to analyze the behavior of water molecules within trabecular bone pores) to characterize the morphology of trabecular bone in osteoporosis. Trabecular bone samples from human femoral heads collected during hip replacement surgery were from osteoporosis (test group) and osteoarthritis (control group) patients. Our data show that both micro- CT and LF-NMR can detect qualitative changes in trabecular bone (i.e., transition from plate-like to rod-like morphology). Micro- CT failed to detect significant differences in trabecular bone morphology parameters between osteoporotic and osteoarthritic specimens, with the exception of Trabecular Number and Connectivity Density, which are markers of osteoporosis progression. In contrast, LF-NMR was able to detect significant differences in porosity and pore size of trabecular bone from osteoporotic versus osteoarthritic (control) samples. However, only the combination of these two techniques allowed the detection of structural morphometric changes (increase in the larger pore fraction and enlargement of the larger pores) in the trabecular bone of osteoporotic specimens compared to osteoarthritic ones. In conclusion, the combined use of LF-NMR and micro- CT provides a valuable tool for characterizing the morphology of trabecular bone and may offer the possibility for a new approach to the study and modeling of bone mechanics in the context of aging and disease.
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Affiliation(s)
- Davide Porrelli
- Department of Medicine, Surgery and Health Sciences, Maggiore Ospital, Trieste University, Piazza dell'Ospitale 1, I-34125, Trieste, Italy
| | - Michela Abrami
- Department of Engineering and Architecture, University of Trieste, Via Valerio 6/A, I 34127, Trieste, Italy
| | - Patrizia Pelizzo
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, I-34149, Trieste, Italy
| | - Cristina Formentin
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, I-34149, Trieste, Italy
| | - Chiara Ratti
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, I-34149, Trieste, Italy
| | - Gianluca Turco
- Department of Medicine, Surgery and Health Sciences, Maggiore Ospital, Trieste University, Piazza dell'Ospitale 1, I-34125, Trieste, Italy
| | - Mario Grassi
- Department of Engineering and Architecture, University of Trieste, Via Valerio 6/A, I 34127, Trieste, Italy.
| | - Gianluca Canton
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, I-34149, Trieste, Italy
| | - Gabriele Grassi
- Department of Life Sciences, Cattinara University Hospital, Trieste University, Strada di Fiume 447, I-34149, Trieste, Italy
| | - Luigi Murena
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, I-34149, Trieste, Italy
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6
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Fowlkes JL, Thrailkill KM, Bunn RC. RASopathies: The musculoskeletal consequences and their etiology and pathogenesis. Bone 2021; 152:116060. [PMID: 34144233 PMCID: PMC8316423 DOI: 10.1016/j.bone.2021.116060] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 01/07/2023]
Abstract
The RASopathies comprise an ever-growing number of clinical syndromes resulting from germline mutations in components of the RAS/MAPK signaling pathway. While multiple organs and tissues may be affected by these mutations, this review will focus on how these mutations specifically impact the musculoskeletal system. Herein, we review the genetics and musculoskeletal phenotypes of these syndromes in humans. We discuss how mutations in the RASopathy syndromes have been studied in translational mouse models. Finally, we discuss how signaling molecules within the RAS/MAPK pathway are involved in normal and abnormal bone biology in the context of osteoblasts, osteoclasts and chondrocytes.
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Affiliation(s)
- John L Fowlkes
- University of Kentucky Barnstable Brown Diabetes Center, Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America.
| | - Kathryn M Thrailkill
- University of Kentucky Barnstable Brown Diabetes Center, Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
| | - R Clay Bunn
- University of Kentucky Barnstable Brown Diabetes Center, Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
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7
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Wei X, Franke J, Ost M, Wardelmann K, Börno S, Timmermann B, Meierhofer D, Kleinridders A, Klaus S, Stricker S. Cell autonomous requirement of neurofibromin (Nf1) for postnatal muscle hypertrophic growth and metabolic homeostasis. J Cachexia Sarcopenia Muscle 2020; 11:1758-1778. [PMID: 33078583 PMCID: PMC7749575 DOI: 10.1002/jcsm.12632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/09/2020] [Accepted: 09/10/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1) is a multi-organ disease caused by mutations in neurofibromin 1 (NF1). Amongst other features, NF1 patients frequently show reduced muscle mass and strength, impairing patients' mobility and increasing the risk of fall. The role of Nf1 in muscle and the cause for the NF1-associated myopathy are mostly unknown. METHODS To dissect the function of Nf1 in muscle, we created muscle-specific knockout mouse models for NF1, inactivating Nf1 in the prenatal myogenic lineage either under the Lbx1 promoter or under the Myf5 promoter. Mice were analysed during prenatal and postnatal myogenesis and muscle growth. RESULTS Nf1Lbx1 and Nf1Myf5 animals showed only mild defects in prenatal myogenesis. Nf1Lbx1 animals were perinatally lethal, while Nf1Myf5 animals survived only up to approximately 25 weeks. A comprehensive phenotypic characterization of Nf1Myf5 animals showed decreased postnatal growth, reduced muscle size, and fast fibre atrophy. Proteome and transcriptome analyses of muscle tissue indicated decreased protein synthesis and increased proteasomal degradation, and decreased glycolytic and increased oxidative activity in muscle tissue. High-resolution respirometry confirmed enhanced oxidative metabolism in Nf1Myf5 muscles, which was concomitant to a fibre type shift from type 2B to type 2A and type 1. Moreover, Nf1Myf5 muscles showed hallmarks of decreased activation of mTORC1 and increased expression of atrogenes. Remarkably, loss of Nf1 promoted a robust activation of AMPK with a gene expression profile indicative of increased fatty acid catabolism. Additionally, we observed a strong induction of genes encoding catabolic cytokines in muscle Nf1Myf5 animals, in line with a drastic reduction of white, but not brown adipose tissue. CONCLUSIONS Our results demonstrate a cell autonomous role for Nf1 in myogenic cells during postnatal muscle growth required for metabolic and proteostatic homeostasis. Furthermore, Nf1 deficiency in muscle drives cross-tissue communication and mobilization of lipid reserves.
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Affiliation(s)
- Xiaoyan Wei
- Musculoskeletal Development and Regeneration Group, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Development and Disease Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Julia Franke
- Musculoskeletal Development and Regeneration Group, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Development and Disease Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Mario Ost
- Department of Physiology of Energy Metabolism, German Institute for Human Nutrition, Nuthetal, Germany.,Department of Neuropathology, University Hospital Leipzig, Leipzig, Germany
| | - Kristina Wardelmann
- Junior Research Group Central Regulation of Metabolism, German Institute for Human Nutrition, Nuthetal, Germany.,Institute of Nutritional Science, Department of Molecular and Experimental Nutritional Medicine, University of Potsdam, Potsdam, Germany
| | - Stefan Börno
- Sequencing Core Unit, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Bernd Timmermann
- Sequencing Core Unit, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - David Meierhofer
- Mass Spectrometry Core Unit, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Andre Kleinridders
- Junior Research Group Central Regulation of Metabolism, German Institute for Human Nutrition, Nuthetal, Germany.,Institute of Nutritional Science, Department of Molecular and Experimental Nutritional Medicine, University of Potsdam, Potsdam, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Susanne Klaus
- Department of Physiology of Energy Metabolism, German Institute for Human Nutrition, Nuthetal, Germany.,Institute of Nutritional Science, University of Potsdam, Potsdam, Germany
| | - Sigmar Stricker
- Musculoskeletal Development and Regeneration Group, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Development and Disease Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
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8
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Grimal Q, Laugier P. Quantitative Ultrasound Assessment of Cortical Bone Properties Beyond Bone Mineral Density. Ing Rech Biomed 2019. [DOI: 10.1016/j.irbm.2018.10.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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9
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Ruggieri M, Praticò AD, Catanzaro S, Palmucci S, Polizzi A. Did Cro-Magnon 1 have neurofibromatosis type 2? Lancet 2018; 392:632-633. [PMID: 30152337 DOI: 10.1016/s0140-6736(18)31544-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 06/27/2018] [Indexed: 10/28/2022]
Affiliation(s)
- Martino Ruggieri
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, 95124 Catania, Italy.
| | - Andrea D Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, 95124 Catania, Italy
| | - Stefano Catanzaro
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, 95124 Catania, Italy
| | - Stefano Palmucci
- Radiology I Unit, Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, Catania, Italy
| | - Agata Polizzi
- National Centre for Rare Diseases, Istituto Superiore di Sanità, Rome, Italy
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10
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Loss of murine Gfi1 causes neutropenia and induces osteoporosis depending on the pathogen load and systemic inflammation. PLoS One 2018; 13:e0198510. [PMID: 29879182 PMCID: PMC5991660 DOI: 10.1371/journal.pone.0198510] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/21/2018] [Indexed: 01/02/2023] Open
Abstract
Gfi1 is a key molecule in hematopoietic lineage development and mutations in GFI1 cause severe congenital neutropenia (SCN). Neutropenia is associated with low bone mass, but the underlying mechanisms are poorly characterized. Using Gfi1 knock-out mice (Gfi1-ko/ko) as SCN model, we studied the relationship between neutropenia and bone mass upon different pathogen load conditions. Our analysis reveals that Gfi1-ko/ko mice kept under strict specific pathogen free (SPF) conditions demonstrate normal bone mass and survival. However, Gfi1-ko/ko mice with early (nonSPF) or late (SPF+nonSPF) pathogen exposure develop low bone mass. Gfi1-ko/ko mice demonstrate a striking rise of systemic inflammatory markers according to elevated pathogen exposure and reduced bone mass. Elevated inflammatory cytokines include for instance Il-1b, Il-6, and Tnf-alpha that regulate osteoclast development. We conclude that low bone mass, due to low neutrophil counts, is caused by the degree of systemic inflammation promoting osteoclastogenesis.
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11
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Charlier P, Benmoussa N, Froesch P, Huynh-Charlier I, Balzeau A. Did Cro-Magnon 1 have neurofibromatosis type 1? Lancet 2018; 391:1259. [PMID: 29619955 DOI: 10.1016/s0140-6736(18)30495-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/20/2018] [Indexed: 10/17/2022]
Affiliation(s)
- Philippe Charlier
- Section of Medical Anthropology, University of Versailles Saint-Quentin-en-Yvelines, 78180 Montigny-Le-Bretonneux, France; Centre d'Accueil et de Soins Hospitaliers and Institut de la Précarité et de l'Exclusion Sociale, Nanterre, France.
| | - Nadia Benmoussa
- Section of Medical Anthropology, University of Versailles Saint-Quentin-en-Yvelines, 78180 Montigny-Le-Bretonneux, France; Department of Otolaryngology-Head and Neck Surgery, Rouen University Hospital, Rouen, France
| | - Philippe Froesch
- Section of Medical Anthropology, University of Versailles Saint-Quentin-en-Yvelines, 78180 Montigny-Le-Bretonneux, France
| | - Isabelle Huynh-Charlier
- Section of Medical Anthropology, University of Versailles Saint-Quentin-en-Yvelines, 78180 Montigny-Le-Bretonneux, France; Department of Radiology, University Hospital Pitié-Salpétrière, Paris, France
| | - Antoine Balzeau
- Section of Human Paleontology, Department of Prehistory, National Museum of Natural History, Musée de l'Homme, Paris, France
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12
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Tai PWL, Wu H, van Wijnen AJ, Stein GS, Stein JL, Lian JB. Genome-wide DNase hypersensitivity, and occupancy of RUNX2 and CTCF reveal a highly dynamic gene regulome during MC3T3 pre-osteoblast differentiation. PLoS One 2017; 12:e0188056. [PMID: 29176792 PMCID: PMC5703546 DOI: 10.1371/journal.pone.0188056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/31/2017] [Indexed: 12/15/2022] Open
Abstract
The ability to discover regulatory sequences that control bone-related genes during development has been greatly improved by massively parallel sequencing methodologies. To expand our understanding of cis-regulatory regions critical to the control of gene expression during osteoblastogenesis, we probed the presence of open chromatin states across the osteoblast genome using global DNase hypersensitivity (DHS) mapping. Our profiling of MC3T3 mouse pre-osteoblasts during differentiation has identified more than 224,000 unique DHS sites. Approximately 65% of these sites are dynamic during temporal stages of osteoblastogenesis, and a majority of them are located within non-promoter (intergenic and intronic) regions. Nearly half of all DHS sites (both constitutive and dynamic) overlap binding events of the bone-essential RUNX2 and/or the chromatin-related CTCF transcription factors. This finding reinforces the role of these regulatory proteins as essential components of the bone gene regulome. We observe a reduction in chromatin accessibility throughout the genome between pre-osteoblast and early osteoblasts. Our analysis also defined a class of differentially expressed genes that harbor DHS peaks centered within 1 kb downstream of transcriptional end sites (TES). These DHSs at the 3’-flanks of genes exhibit dynamic changes during differentiation that may impact regulation of the osteoblast genome. Taken together, the distribution of DHS regions within non-promoter locations harboring osteoblast and chromatin related transcription factor binding motifs, reflect novel cis-regulatory requirements to support temporal gene expression in differentiating osteoblasts.
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Affiliation(s)
- Phillip W. L. Tai
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Hai Wu
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | | | - Gary S. Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Janet L. Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
- * E-mail: (JLS); (JBL)
| | - Jane B. Lian
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
- * E-mail: (JLS); (JBL)
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13
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Dubansky BH, Dubansky BD. Natural development of dermal ectopic bone in the american alligator (Alligator mississippiensis
) resembles heterotopic ossification disorders in humans. Anat Rec (Hoboken) 2017; 301:56-76. [DOI: 10.1002/ar.23682] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/25/2017] [Accepted: 08/17/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Brooke H. Dubansky
- Department of Medical Laboratory Sciences and Public Health; Tarleton State University; 1501 Enderly Place, Fort Worth Texas
| | - Benjamin D. Dubansky
- Department of Biological Sciences; University of North Texas, 1511 W. Sycamore St; Denton Texas
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14
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Gräsel M, Glüer CC, Barkmann R. Characterization of a new ultrasound device designed for measuring cortical porosity at the human tibia: A phantom study. ULTRASONICS 2017; 76:183-191. [PMID: 28107676 DOI: 10.1016/j.ultras.2017.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/30/2016] [Accepted: 01/02/2017] [Indexed: 06/06/2023]
Abstract
Quantitative ultrasound (QUS) measurements of trabecular bone are a useful tool for the assessment of osteoporotic fracture risk. However, cortical bone properties (e.g. porosity) have an impact on bone strength as well and thus current research is focused on QUS assessment of cortical bone properties. Simulation studies of ultrasound propagation through cortical bone indicate that anisotropy, calculated from the ratio of the velocities in axial and tangential directions, is correlated with porosity. However, this relationship is affected by error sources, specifically bone surface curvature and variability of probe positioning. With the aim of in vivo estimation of cortical porosity a new ultrasound device was developed, which sequentially measures velocities in 3 different directions (axial=0° and ±37.5°) using the axial transmission method. Measurements on planar porosity phantoms (0-25%) were performed to confirm the results of the afore mentioned simulation studies. Additionally, measurements on cylindrical phantoms without pores (min. radius=34mm for strongest curvature) were performed to estimate the influence of surface curvature on velocity measurements (the tibia bone surface is fairly flat but may show surface curvature in some patients). The velocities in the axial and ±37.5° directions were used to calculate an anisotropy index. The velocities measured on the porosity phantoms showed a decrease by -6.3±0.2m/s and -10.1±0.2m/s per percent increase in porosity in axial and ±37.5° directions, respectively. Surface curvature had an effect on the velocities measured in ±37.5° directions which could be minimized by a correction algorithm resulting in an error of 5m/s. The anisotropy index could be used to estimate porosity with an accuracy error of 1.5%. These results indicate that an estimation of porosity using velocity measurements in different directions might be feasible, even in bones with curved surface. These results obtained on phantom material indicate that the approach tested may be suited for porosity measurements on human tibia bone.
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Affiliation(s)
- M Gräsel
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Am Botanischen Garten 14, 24118 Kiel, Germany.
| | - C-C Glüer
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Am Botanischen Garten 14, 24118 Kiel, Germany.
| | - R Barkmann
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Am Botanischen Garten 14, 24118 Kiel, Germany.
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15
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Poyrazoğlu HG, Baş VN, Arslan A, Bastug F, Canpolat M, Per H, Gümüs H, Kumandas S. Bone mineral density and bone metabolic markers' status in children with neurofibromatosis type 1. J Pediatr Endocrinol Metab 2017; 30:175-180. [PMID: 28125404 DOI: 10.1515/jpem-2016-0092] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 11/21/2016] [Indexed: 11/15/2022]
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1) is a multisystem disorder characterized by progressive manifestations, which is inherited in an autosomal dominant manner. The majority of patients with NF1 experience a diffuse, significant reduction in bone mass over time, with osteoporosis, osteopenia in the absence of severe scoliosis, or gross bone deformities. This study aimed to determine the bone mineral density (BMD) status, evaluate bone metabolism, and to determine the relevant factors in children with NF1. METHODS The study population included 33 pediatric NF1 patients (20 males and 13 females). Bone metabolic markers, such as total calcium, phosphorus, magnesium, alkaline phosphatase, parathyroid hormone, and 25-OH vitamin D, the urinary calcium/creatine ratio were measured. In addition, BMD was measured at both the lumbar spine (LS) and the femoral neck in all the patients. RESULTS All the patients had a low 25-OH vitamin D level, but it was significantly lower in the females than in the males (p<0.009). Overall, 18.2% of the patients had skeletal abnormalities. The lumbar Z-score was ≤2 in 21.2% of the patients, whereas the femoral neck Z-score was ≤2 in 9.1%. The urinary calcium/creatine ratio was significantly higher in the female than in the male patients (p<0.027). In all, six patients had skeletal abnormalities. CONCLUSIONS It is widely known that bone mineral metabolism markers and BMD are significantly affected in NF1 patients; however, the present study did not identify any effective parameters that could be used to predict skeletal abnormalities, or diagnose early osteoporosis and osteopenia in pediatric NF1 patients.
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16
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Kerckhofs G, Durand M, Vangoitsenhoven R, Marin C, Van der Schueren B, Carmeliet G, Luyten FP, Geris L, Vandamme K. Changes in bone macro- and microstructure in diabetic obese mice revealed by high resolution microfocus X-ray computed tomography. Sci Rep 2016; 6:35517. [PMID: 27759061 PMCID: PMC5069481 DOI: 10.1038/srep35517] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/26/2016] [Indexed: 02/03/2023] Open
Abstract
High resolution microfocus X-ray computed tomography (HR-microCT) was employed to characterize the structural alterations of the cortical and trabecular bone in a mouse model of obesity-driven type 2 diabetes (T2DM). C57Bl/6J mice were randomly assigned for 14 weeks to either a control diet-fed (CTRL) or a high fat diet (HFD)-fed group developing obesity, hyperglycaemia and insulin resistance. The HFD group showed an increased trabecular thickness and a decreased trabecular number compared to CTRL animals. Midshaft tibia intracortical porosity was assessed at two spatial image resolutions. At 2 μm scale, no change was observed in the intracortical structure. At 1 μm scale, a decrease in the cortical vascular porosity of the HFD bone was evidenced. The study of a group of 8 week old animals corresponding to animals at the start of the diet challenge revealed that the decreased vascular porosity was T2DM-dependant and not related to the ageing process. Our results offer an unprecedented ultra-characterization of the T2DM compromised skeletal micro-architecture and highlight an unrevealed T2DM-related decrease in the cortical vascular porosity, potentially affecting the bone health and fragility. Additionally, it provides some insights into the technical challenge facing the assessment of the rodent bone structure using HR-microCT imaging.
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Affiliation(s)
- G. Kerckhofs
- Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium
- Prometheus - Division of Skeletal Tissue Engineering Leuven, KU Leuven, 3000 Leuven, Belgium
| | - M. Durand
- Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium
- Prometheus - Division of Skeletal Tissue Engineering Leuven, KU Leuven, 3000 Leuven, Belgium
- UMR CNRS 7052, Biomécanique et Biomatériaux Ostéo-Articulaires, Faculté de Médecine Lariboisière, 75000 Paris, France
- Institut de Recherche Biomédicale des Armées (IRBA), Département Soutien Médico-Chirurgical des Forces (SMCF), 91220 Brétigny-sur-Orge, France
| | - R. Vangoitsenhoven
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - C. Marin
- Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium
- Prometheus - Division of Skeletal Tissue Engineering Leuven, KU Leuven, 3000 Leuven, Belgium
| | - B. Van der Schueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - G. Carmeliet
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - F. P. Luyten
- Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium
- Prometheus - Division of Skeletal Tissue Engineering Leuven, KU Leuven, 3000 Leuven, Belgium
| | - L. Geris
- Prometheus - Division of Skeletal Tissue Engineering Leuven, KU Leuven, 3000 Leuven, Belgium
- Division of Biomechanics and Engineering Design, KU Leuven, 3001 Heverlee, Belgium
- Biomechanics Research Unit, University of Liège, 4000 Liège, Belgium
| | - K. Vandamme
- Prometheus - Division of Skeletal Tissue Engineering Leuven, KU Leuven, 3000 Leuven, Belgium
- Biomaterials – BIOMAT, Department of Oral Health Sciences, KU Leuven, 3000 Leuven, Belgium
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17
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Capturing the wide variety of impaired fracture healing phenotypes in Neurofibromatosis Type 1 with eight key factors: a computational study. Sci Rep 2016; 7:20010. [PMID: 26822862 PMCID: PMC4731811 DOI: 10.1038/srep20010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 11/27/2015] [Indexed: 02/07/2023] Open
Abstract
Congenital pseudarthrosis of the tibia (CPT) is a rare disease which normally presents itself during early childhood by anterolateral bowing of the tibia and spontaneous tibial fractures. Although the exact etiology of CPT is highly debated, 40–80% of CPT patients are carriers of a mutation in the Neurofibromatosis Type 1 (NF1) gene, which can potentially result in an altered phenotype of the skeletal cells and impaired bone healing. In this study we use a computational model of bone regeneration to examine the effect of the Nf1 mutation on bone fracture healing by altering the parameter values of eight key factors which describe the aberrant cellular behaviour of Nf1 haploinsufficient and Nf1 bi-allelically inactivated cells. We show that the computational model is able to predict the formation of a hamartoma as well as a wide variety of CPT phenotypes through different combinations of altered parameter values. A sensitivity analysis by “Design of Experiments” identified the impaired endochondral ossification process and increased infiltration of fibroblastic cells as key contributors to the degree of severity of CPT. Hence, the computational model results have added credibility to the experimental hypothesis of a genetic cause (i.e. Nf1 mutation) for CPT.
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18
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Jepsen KJ, Silva MJ, Vashishth D, Guo XE, van der Meulen MCH. Establishing biomechanical mechanisms in mouse models: practical guidelines for systematically evaluating phenotypic changes in the diaphyses of long bones. J Bone Miner Res 2015; 30:951-66. [PMID: 25917136 PMCID: PMC4794979 DOI: 10.1002/jbmr.2539] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/03/2015] [Accepted: 04/21/2015] [Indexed: 12/30/2022]
Abstract
Mice are widely used in studies of skeletal biology, and assessment of their bones by mechanical testing is a critical step when evaluating the functional effects of an experimental perturbation. For example, a gene knockout may target a pathway important in bone formation and result in a "low bone mass" phenotype. But how well does the skeleton bear functional loads; eg, how much do bones deform during loading and how resistant are bones to fracture? By systematic evaluation of bone morphological, densitometric, and mechanical properties, investigators can establish the "biomechanical mechanisms" whereby an experimental perturbation alters whole-bone mechanical function. The goal of this review is to clarify these biomechanical mechanisms and to make recommendations for systematically evaluating phenotypic changes in mouse bones, with a focus on long-bone diaphyses and cortical bone. Further, minimum reportable standards for testing conditions and outcome variables are suggested that will improve the comparison of data across studies. Basic biomechanical principles are reviewed, followed by a description of the cross-sectional morphological properties that best inform the net cellular effects of a given experimental perturbation and are most relevant to biomechanical function. Although morphology is critical, whole-bone mechanical properties can only be determined accurately by a mechanical test. The functional importance of stiffness, maximum load, postyield displacement, and work-to-fracture are reviewed. Because bone and body size are often strongly related, strategies to adjust whole-bone properties for body mass are detailed. Finally, a comprehensive framework is presented using real data, and several examples from the literature are reviewed to illustrate how to synthesize morphological, tissue-level, and whole-bone mechanical properties of mouse long bones.
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Affiliation(s)
- Karl J Jepsen
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Matthew J Silva
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Deepak Vashishth
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - X Edward Guo
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Marjolein CH van der Meulen
- Department of Biomedical Engineering and Sibley School of Mechanical & Aerospace Engineering, Cornell University, Ithaca, NY, USA
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19
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Kühnisch J, Seto J, Lange C, Stumpp S, Kobus K, Grohmann J, Elefteriou F, Fratzl P, Mundlos S, Kolanczyk M. Neurofibromin inactivation impairs osteocyte development in Nf1Prx1 and Nf1Col1 mouse models. Bone 2014; 66:155-62. [PMID: 24947449 DOI: 10.1016/j.bone.2014.06.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 06/06/2014] [Accepted: 06/09/2014] [Indexed: 12/18/2022]
Abstract
Neurofibromin has been identified as a critical regulator of osteoblast differentiation. Osteoblast specific inactivation of neurofibromin in mice results in a high bone mass phenotype and hyperosteoidosis. Here, we show that inactivation of the Nf1 gene also impairs osteocyte development. We analyzed cortical bone tissue in two conditional mouse models, Nf1Prx1 and Nf1Col1, for morphological and molecular effects. Backscattered electron microscopy revealed significantly enlarged osteocyte lacunae in Nf1Prx1 and Nf1Col1 mice (level E2: ctrl=1.90±0.52%, Nf1Prx1=3.40±0.95%; ctrl 1.60±0.47%, Nf1Col1 2.46±0.91%). Moreover, the osteocyte lacunae appeared misshaped in Nf1Prx1 and Nf1Col1 mice as indicated by increased Feret ratios. Strongest osteocyte and dendritic network disorganization was observed in proximity of muscle attachment sites in Nf1Prx1 humeri. In contrast to control cells, Nf1Prx1 osteocytes contained abundant cytosolic vacuoles and accumulated immature organic matrix within the perilacunar space, a phenotype reminiscent of the hyperosteoidosis shown Nf1 deficient mice. Cortical bone lysates further revealed approx. twofold upregulated MAPK signalling in osteocytes of Nf1Prx1 mice. This was associated with transcriptional downregulation of collagens and genes involved in mechanical sensing in Nf1Prx1 and Nf1Col1 bone tissue. In contrast, matrix gla protein (MGP), phosphate regulating endopeptidase homolog, X-linked (PHEX), and genes involved in lipid metabolism were upregulated. In line with previously described hyperactivation of Nf1 deficient osteoblasts, systemic plasma levels of the bone formation markers osteocalcin (OCN) and procollagen typ I N-propeptide (PINP) were approx. twofold increased in Nf1Prx1 mice. Histochemical and molecular analysis ascertained that osteocytes in Nf1Prx1 cortical bone were viable and did not undergo apoptosis or autophagy. We conclude that loss of neurofibromin is not only critical for osteoblasts but also hinders normal osteocyte development. These findings expand the effect of neurofibromin onto yet another cell type where it is likely involved in the regulation of mechanical sensing, bone matrix composition and mechanical resistance of bone tissue.
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Affiliation(s)
- Jirko Kühnisch
- Institute for Medical Genetics and Human Genetics, Charité, Universitätsmedizin Berlin, Berlin, Germany; FG Development & Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany.
| | - Jong Seto
- Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Potsdam, Germany; Department of Chemistry, École Normale Superiéure, 24 rue Lhomond, Paris 75005, France
| | - Claudia Lange
- Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Potsdam, Germany; Institut für Physiologische Chemie, MTZ, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Sabine Stumpp
- Institute for Medical Genetics and Human Genetics, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Karolina Kobus
- FG Development & Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Julia Grohmann
- FG Development & Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Florent Elefteriou
- Department of Medicine, Pharmacology and Cancer Biology, Center for Bone Biology, Vanderbilt University Medical Center, Nashville TN, USA
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Potsdam, Germany; Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Berlin, Germany
| | - Stefan Mundlos
- Institute for Medical Genetics and Human Genetics, Charité, Universitätsmedizin Berlin, Berlin, Germany; FG Development & Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany; Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Berlin, Germany
| | - Mateusz Kolanczyk
- Institute for Medical Genetics and Human Genetics, Charité, Universitätsmedizin Berlin, Berlin, Germany; FG Development & Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany.
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20
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Abstract
The ability of bone to resist fracture is determined by the combination of bone mass and bone quality. Like bone mass, bone quality is carefully regulated. Of the many aspects of bone quality, this review focuses on biological mechanisms that control the material quality of the bone extracellular matrix (ECM). Bone ECM quality depends upon ECM composition and organization. Proteins and signaling pathways that affect the mineral or organic constituents of bone ECM impact bone ECM material properties, such as elastic modulus and hardness. These properties are also sensitive to pathways that regulate bone remodeling by osteoblasts, osteoclasts, and osteocytes. Several extracellular proteins, signaling pathways, intracellular effectors, and transcription regulatory networks have been implicated in the control of bone ECM quality. A molecular understanding of these mechanisms will elucidate the biological control of bone quality and suggest new targets for the development of therapies to prevent bone fragility.
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Affiliation(s)
- Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, 513 Parnassus Avenue, Room S-1155, San Francisco, CA, 94143-0514, USA,
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21
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de la Croix Ndong J, Makowski AJ, Uppuganti S, Vignaux G, Ono K, Perrien DS, Joubert S, Baglio SR, Granchi D, Stevenson DA, Rios JJ, Nyman JS, Elefteriou F. Asfotase-α improves bone growth, mineralization and strength in mouse models of neurofibromatosis type-1. Nat Med 2014; 20:904-10. [PMID: 24997609 PMCID: PMC4126855 DOI: 10.1038/nm.3583] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 05/01/2014] [Indexed: 12/20/2022]
Abstract
Mineralization of the skeleton depends on the balance between levels of
pyrophosphate (PPi), an inhibitor of hydroxyapatite formation, and phosphate generated
from PPi breakdown by alkaline phosphatase (ALP). We report here that ablation of
Nf1, encoding the RAS/GTPase–activating protein neurofibromin,
in bone–forming cells leads to supraphysiologic PPi accumulation, caused by a
chronic ERK–dependent increase in genes promoting PPi synthesis and extracellular
transport, namely Enpp1 and Ank. It also prevents
BMP2–induced osteoprogenitor differentiation and, consequently, expression of ALP
and PPi breakdown, further contributing to PPi accumulation. The short stature, impaired
bone mineralization and strength in mice lacking Nf1 in
osteochondroprogenitors or osteoblasts could be corrected by enzyme therapy aimed at
reducing PPi concentration. These results establish neurofibromin as an essential
regulator of bone mineralization, suggest that altered PPi homeostasis contributes to the
skeletal dysplasiae associated with neurofibromatosis type-1 (NF1), and that some of the
NF1 skeletal conditions might be preventable pharmacologically.
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Affiliation(s)
- Jean de la Croix Ndong
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alexander J Makowski
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA. [3] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [4] Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Sasidhar Uppuganti
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Guillaume Vignaux
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Koichiro Ono
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [3] Department of Orthopaedics, Nohon Koukan Hospital, Kawasaki, Kanagawa, Japan
| | - Daniel S Perrien
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [3] Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA. [4] Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Serena R Baglio
- Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Donatella Granchi
- Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - David A Stevenson
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Jonathan J Rios
- 1] Sarah M. and Charles E. Seay Center for Musculoskeletal Research, Texas Scottish Rite Hospital for Children, Dallas, Texas, USA. [2] Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA. [3] Eugene McDermott Center for Human Growth &Development, UT Southwestern Medical Center, Dallas, Texas, USA. [4] Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jeffry S Nyman
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA. [3] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [4] Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Florent Elefteriou
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [3] Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [4] Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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