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Spoutil F, Dlugosova S, Varga I, Aranaz-Novaliches G, Novosadova V, Prochazkova M, Sedlacek R, Prochazka J. Semi-Automated MicroCT Analysis of Bone Anatomy and Mineralization in Mouse Models. Curr Protoc 2024; 4:e980. [PMID: 38385868 DOI: 10.1002/cpz1.980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
The skeletal system mirrors several processes in the vertebrate body that impact developmental malfunctions, hormonal disbalance, malfunction of calcium metabolism and turn over, and inflammation processes such as arthrosis. X-ray micro computed tomography is a useful tool for 3D in situ evaluation of the skeletal system in a time-related manner, but results depend highly on resolution. Here, we provide the methodological background for a graduated evaluation from whole-body analysis of skeletal morphology and mineralization to high-resolution analysis of femoral and vertebral microstructure. We combine an expert-based evaluation with a machine-learning-based computational approach, including pre-setup analytical task lists. © 2024 Wiley Periodicals LLC. Basic Protocol 1: In vivo microCT scanning and skeletal analysis in mice Basic Protocol 2: Ex vivo high-resolution microCT scanning and microstructural analysis of the femur and L4 vertebra.
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Affiliation(s)
- Frantisek Spoutil
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sylvie Dlugosova
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Igor Varga
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Department of Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
| | - Goretti Aranaz-Novaliches
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vendula Novosadova
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Michaela Prochazkova
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radislav Sedlacek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Prochazka
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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Chanpaisaeng K, Reyes‐Fernandez PC, Dilkes B, Fleet JC. Diet X Gene Interactions Control Femoral Bone Adaptation To Low Dietary Calcium. JBMR Plus 2022; 6:e10668. [PMID: 36111202 PMCID: PMC9465001 DOI: 10.1002/jbm4.10668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/29/2022] [Accepted: 07/22/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
- Krittikan Chanpaisaeng
- Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA) Pathum Thani Thailand
| | - Perla C. Reyes‐Fernandez
- School of Health and Human Sciences, Department of Physical Therapy Indiana University ‐ Purdue University Indianapolis Indianapolis IN USA
| | - Brian Dilkes
- Center for Plant Biology Purdue University West Lafayette IN USA
- Department of Biochemistry Purdue University West Lafayette IN USA
| | - James C. Fleet
- Department of Nutritional Sciences and the Dell Pediatric Research Institute University of Texas Austin TX USA
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Addison BJ, Lieberman DE. Assessing patterns of variation in BV/TV in the calcaneus and C2 vertebra of Gorilla gorilla, Pan troglodytes, and populations of Homo sapiens from the Pleistocene and Holocene that differ in physical activity levels. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 173:337-349. [PMID: 33448347 DOI: 10.1002/ajpa.24064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 02/26/2020] [Accepted: 04/10/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Because trabecular bone volume fraction (BV/TV) is influenced by variations in physical activity recent declines in BV/TV in humans are often attributed to modern sedentary lifestyles. This study tests the hypothesis that presumed variations in mechanical loading between groups can predict the observed BV/TV patterns in humans, chimpanzees and gorillas in two bones: the calcaneus which experiences high and well characterized impact forces, and the C2 vertebrae which experiences reduced locomotor forces. MATERIALS AND METHODS BV/TV and other structural variables were quantified from high-resolution microCT scans in gorillas, chimpanzees, and four Homo sapiens populations: Pleistocene, semi-sedentary Natufians; Holocene hunter-gatherers from Point Hope, Alaska; Holocene nomadic pastoralists from medieval Europe; and modern, sedentary Americans. RESULTS In the calcaneal tuberosity, Natufian BV/TV was 36, 46, and 46% greater than Alaskans (p = .02), Europeans (p = .005) and modern Americans (p = .002), respectively, but not significantly different from apes. BV/TV was not significantly different between modern Americans and Alaskans or Europeans. In the C2, Natufian BV/TV was 53 and 25% greater than in the Alaskan (p = .0001) and European (p = .048) populations. DISCUSSION These results suggest that phenomena other than or in addition to variations in physical activity are needed to explain BV/TV patterns observed in H. sapiens, and point to a systemic decline in H. sapiens BV/TV after the Pleistocene.
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Affiliation(s)
- Brian J Addison
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States
| | - Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States
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Lu L, Huang J, Xu F, Xiao Z, Wang J, Zhang B, David NV, Arends D, Gu W, Ackert-Bicknell C, Sabik OL, Farber CR, Quarles LD, Williams RW. Genetic Dissection of Femoral and Tibial Microarchitecture. JBMR Plus 2019; 3:e10241. [PMID: 31844829 PMCID: PMC6894729 DOI: 10.1002/jbm4.10241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 09/09/2019] [Accepted: 09/16/2019] [Indexed: 12/29/2022] Open
Abstract
Our understanding of the genetic control of bone strength has relied mainly on estimates of bone mineral density. Here we have mapped genetic factors that influence femoral and tibial microarchitecture using high‐resolution x‐ray computed tomography (8‐μm isotropic voxels) across a family of 61 BXD strains of mice, roughly 10 isogenic cases per strain and balanced by sex. We computed heritabilities for 25 cortical and trabecular traits. Males and females have well‐matched heritabilities, ranging from 0.25 to 0.75. We mapped 16 genetic loci most of which were detected only in females. There is also a bias in favor of loci that control cortical rather than trabecular bone. To evaluate candidate genes, we combined well‐established gene ontologies with bone transcriptome data to compute bone‐enrichment scores for all protein‐coding genes. We aligned candidates with those of human genome‐wide association studies. A subset of 50 strong candidates fell into three categories: (1) experimentally validated genes already known to modulate bone function (Adamts4, Ddr2, Darc, Adam12, Fkbp10, E2f6, Adam17, Grem2, Ifi204); (2) candidates without any experimentally validated function in bone (eg, Greb1, Ifi202b), but linked to skeletal phenotypes in human cohorts; and (3) candidates that have high bone‐enrichment scores, but for which there is not yet any functional link to bone biology or skeletal system disease (including Ifi202b, Ly9, Ifi205, Mgmt, F2rl1, Iqgap2). Our results highlight contrasting genetic architecture between sexes and among major bone compartments. The alignment of murine and human data facilitates function analysis and should prove of value for preclinical testing of molecular control of bone structure. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Lu Lu
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
| | - Jinsong Huang
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
| | - Fuyi Xu
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
| | - Zhousheng Xiao
- Department of Medicine University of Tennessee Health Science Center Memphis TN USA
| | - Jing Wang
- Department of Molecular and Human Genetics Baylor College of Medicine Houston TX USA
| | - Bing Zhang
- Department of Molecular and Human Genetics Baylor College of Medicine Houston TX USA
| | - Nicolae Valentin David
- Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Danny Arends
- Breeding Biology and Molecular Animal Breeding Humboldt University Berlin Germany
| | - Weikuan Gu
- Department of Orthopaedic Surgery and Biomedical Engineering University of Tennessee Health Science Center Memphis TN USA
| | | | - Olivia L Sabik
- Center for Public Health Genomics University of Virginia Charlottesville VA USA
| | - Charles R Farber
- Center for Public Health Genomics University of Virginia Charlottesville VA USA
| | - Leigh Darryl Quarles
- Department of Medicine University of Tennessee Health Science Center Memphis TN USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
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Chanpaisaeng K, Reyes Fernandez PC, Fleet JC. Dietary calcium intake and genetics have site-specific effects on peak trabecular bone mass and microarchitecture in male mice. Bone 2019; 125:46-53. [PMID: 31078711 PMCID: PMC6604851 DOI: 10.1016/j.bone.2019.05.011] [Citation(s) in RCA: 2] [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: 01/28/2019] [Revised: 04/20/2019] [Accepted: 05/08/2019] [Indexed: 11/30/2022]
Abstract
Trabecular bone (Tb) is used for rapid exchange of calcium (Ca) in times of physiologic need and the site-specific characteristics of Tb may explain why certain sites are more vulnerable to osteoporosis. We hypothesized that peak trabecular bone mass (PTBM) and Tb microarchitecture are differentially regulated by dietary Ca intake, genetics, or Gene-by-Diet (GxD) interactions at the distal femur and the fifth lumbar (L5) vertebra. Male mice from 62 genetically distinct lines were fed basal (0.5%) or low (0.25%) Ca diets from 4 to 12 wks of age. Afterwards, the right femur and L5 vertebra were removed and trabecular bone was analyzed by μCT. In mice fed the basal diet, bone volume fraction (BV/TV), trabecular number (Tb.N), and connectivity density (Conn.D) were significantly higher in the L5 vertebra than femur. Femur Tb had a weaker, more rod-like structure than the L5 vertebrae while mice fed the low Ca diet developed rod-like structures at both sites. Dietary Ca restriction also caused a greater relative reduction of Tb.N and Conn.D in the femur than L5 vertebra, i.e. it was more harmful to the integrity of Tb microarchitecture in femur. Genetics was a major determinant of Tb at both sites, e.g. heritability of BV/TV on the basal diet = 0.65 (femur) and 0.68 (L5 vertebra). However, while GxD interactions altered the impact of dietary Ca restriction on Tb parameters at both sites, the effect was not uniform, e.g. some lines had site-specific responses to Ca restriction. The significance of our work is that there are site-specific effects of dietary Ca restriction and genetics that work independently and interactively to influence the attainment of PTBM and Tb microarchitecture.
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Affiliation(s)
- Krittikan Chanpaisaeng
- Department of Nutrition Science, Purdue University, USA; Interdepartmental Graduate Nutrition Program (INP), Purdue University, USA
| | - Perla C Reyes Fernandez
- Department of Nutrition Science, Purdue University, USA; Interdepartmental Graduate Nutrition Program (INP), Purdue University, USA
| | - James C Fleet
- Department of Nutrition Science, Purdue University, USA; Interdepartmental Graduate Nutrition Program (INP), Purdue University, USA.
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Zaitune CR, Fonseca TL, Capelo LP, Freitas FR, Beber EH, Dora JM, Wang CC, Miranda-Rodrigues M, Nonaka KO, Maia AL, Gouveia CHA. Abnormal Thyroid Hormone Status Differentially Affects Bone Mass Accrual and Bone Strength in C3H/HeJ Mice: A Mouse Model of Type I Deiodinase Deficiency. Front Endocrinol (Lausanne) 2019; 10:300. [PMID: 31156551 PMCID: PMC6530334 DOI: 10.3389/fendo.2019.00300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/26/2019] [Indexed: 12/26/2022] Open
Abstract
C3H/HeJ (C3H) mice are deficient of type I deiodinase (D1), an enzyme that activates thyroid hormone (TH), converting thyroxine (T4) to triiodothyronine (T3). Nevertheless, C3H mice present normal serum T3 and a gross euthyroid phenotype. To investigate if a global D1 deficiency interferes in the TH effects on bone, we compared bone growth, bone mass accrual and bone strength of C3H and C57BL/6J (B6) mice under abnormal TH status. Four-week-old female mice of both strains were grouped as Euthyroid, Hypothyroid (pharmacologically-induced), 1xT4 and 10xT4 (hypothyroid animals receiving 1- or 10-fold the physiological dose of T4 /day/16 weeks). Hypothyroidism and TH excess similarly impaired body weight (BW) gain and body growth in both mice strains. In contrast, whereas hypothyroidism only slightly impaired bone mineral density (BMD) accrual in B6 mice, it severely impaired BMD accrual in C3H mice. No differences were observed in serum and bone concentrations of T3 between hypothyroid animals of both strains. Interestingly, treatment with 10xT4 was less deleterious to BMD accrual in C3H than in B6 mice and resulted in less elevated T3 serum levels in B6 than in C3H mice, which is probably explained by the lower D1 activity in C3H mice. In addition, hypothyroidism decreased bone strength only in C3H but not in B6 mice, while TH excess decreased this parameter in both strains. These findings indicate that D1 deficiency contributes to the TH excess-induced differences in bone mass accrual in C3H vs. B6 mice and suggest that deiodinase-unrelated genetic factors might account for the different skeleton responses to hypothyroidism between strains.
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Affiliation(s)
- Clarissa R. Zaitune
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Institute of Healthy Sciences, Paulista University, São Paulo, Brazil
| | - Tatiana L. Fonseca
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Chicago, Chigago, IL, United States
| | - Luciane P. Capelo
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Institute of Science and Technology, Federal University of São Paulo, São Paulo, Brazil
| | - Fatima R. Freitas
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Heart Institute (InCor) of Medical School Hospital, University of São Paulo, São Paulo, Brazil
| | - Eduardo H. Beber
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo, Vitoria, Brazil
| | - José M. Dora
- Endocrine Division, Hospital de Clinicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Charles C. Wang
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil
| | - Manuela Miranda-Rodrigues
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Keico O. Nonaka
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil
| | - Ana L. Maia
- Endocrine Division, Hospital de Clinicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Cecilia H. A. Gouveia
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- *Correspondence: Cecilia H. A. Gouveia
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Maynard RD, Ackert-Bicknell CL. Mouse Models and Online Resources for Functional Analysis of Osteoporosis Genome-Wide Association Studies. Front Endocrinol (Lausanne) 2019; 10:277. [PMID: 31133984 PMCID: PMC6515928 DOI: 10.3389/fendo.2019.00277] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/16/2019] [Indexed: 12/13/2022] Open
Abstract
Osteoporosis is a complex genetic disease in which the number of loci associated with the bone mineral density, a clinical risk factor for fracture, has increased at an exponential rate in the last decade. The identification of the causative variants and candidate genes underlying these loci has not been able to keep pace with the rate of locus discovery. A large number of tools and data resources have been built around the use of the mouse as model of human genetic disease. Herein, we describe resources available for functional validation of human Genome Wide Association Study (GWAS) loci using mouse models. We specifically focus on large-scale phenotyping efforts focused on bone relevant phenotypes and repositories of genotype-phenotype data that exist for transgenic and mutant mice, which can be readily mined as a first step toward more targeted efforts designed to deeply characterize the role of a gene in bone biology.
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Affiliation(s)
- Robert D. Maynard
- Center for Musculoskeletal Research, University of Rochester, Rochester, NY, United States
| | - Cheryl L. Ackert-Bicknell
- Center for Musculoskeletal Research, University of Rochester, Rochester, NY, United States
- Department of Orthopaedics and Rehabilitation, University of Rochester, Rochester, NY, United States
- *Correspondence: Cheryl L. Ackert-Bicknell
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Rowe DW, Adams DJ, Hong SH, Zhang C, Shin DG, Renata Rydzik C, Chen L, Wu Z, Garland G, Godfrey DA, Sundberg JP, Ackert-Bicknell C. Screening Gene Knockout Mice for Variation in Bone Mass: Analysis by μCT and Histomorphometry. Curr Osteoporos Rep 2018; 16:77-94. [PMID: 29508144 DOI: 10.1007/s11914-018-0421-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW The international mouse phenotyping consortium (IMPC) is producing defined gene knockout mouse lines. Here, a phenotyping program is presented that is based on micro-computed tomography (μCT) assessment of distal femur and vertebra. Lines with significant variation undergo a computer-based bone histomorphometric analysis. RECENT FINDINGS Of the 220 lines examined to date, approximately 15% have a significant variation (high or low) by μCT, most of which are not identified by the IMPC screen. Significant dimorphism between the sexes and bone compartments adds to the complexity of the skeletal findings. The μCT information that is posted at www.bonebase.org can group KOMP lines with similar morphological features. The histological data is presented in a graphic form that associates the cellular features with a specific anatomic group. The web portal presents a bone-centric view appropriate for the skeletal biologist/clinician to organize and understand the large number of genes that can influence skeletal health. Cataloging the relative severity of each variant is the first step towards compiling the dataset necessary to appreciate the full polygenic basis of degenerative bone disease.
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Affiliation(s)
- David W Rowe
- Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, Biomaterials and Skeletal Development, School of Dental Medicine, University of Connecticut Health, Farmington, CT, 06030, USA.
| | - Douglas J Adams
- Department of Orthopaedic Surgery, School of Medicine, University of Connecticut Health, Farmington, CT, 06030, USA
| | - Seung-Hyun Hong
- Computer Science and Engineering, School of Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - Caibin Zhang
- Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, Biomaterials and Skeletal Development, School of Dental Medicine, University of Connecticut Health, Farmington, CT, 06030, USA
| | - Dong-Guk Shin
- Computer Science and Engineering, School of Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - C Renata Rydzik
- Department of Orthopaedic Surgery, School of Medicine, University of Connecticut Health, Farmington, CT, 06030, USA
| | - Li Chen
- Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, Biomaterials and Skeletal Development, School of Dental Medicine, University of Connecticut Health, Farmington, CT, 06030, USA
| | - Zhihua Wu
- Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, Biomaterials and Skeletal Development, School of Dental Medicine, University of Connecticut Health, Farmington, CT, 06030, USA
| | | | - Dana A Godfrey
- Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester School of Medicine, Rochester, NY, 14642, USA
| | | | - Cheryl Ackert-Bicknell
- Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester School of Medicine, Rochester, NY, 14642, USA
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Villamil CI. Phenotypic integration of the cervical vertebrae in the Hominoidea (Primates). Evolution 2018; 72:490-517. [DOI: 10.1111/evo.13433] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Catalina I. Villamil
- Department of Anthropology; Dickinson College; P.O. Box 1773 Carlisle Pennsylvania 17013
- Center for the Study of Human Origins, Department of Anthropology; New York University; 25 Waverly Place New York New York 10003
- New York Consortium in Evolutionary Primatology; New York New York 10024
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Genetic Dissection of Trabecular Bone Structure with Mouse Intersubspecific Consomic Strains. G3-GENES GENOMES GENETICS 2017; 7:3449-3457. [PMID: 28855285 PMCID: PMC5633393 DOI: 10.1534/g3.117.300213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Trabecular bone structure has an important influence on bone strength, but little is known about its genetic regulation. To elucidate the genetic factor(s) regulating trabecular bone structure, we compared the trabecular bone structures of two genetically remote mouse strains, C57BL/6J and Japanese wild mouse-derived MSM/Ms. Phenotyping by X-ray micro-CT revealed that MSM/Ms has structurally more fragile trabecular bone than C57BL/6J. Toward identification of genetic determinants for the difference in fragility of trabecular bone between the two mouse strains, we employed phenotype screening of consomic mouse strains in which each C57BL/6J chromosome is substituted by its counterpart from MSM/Ms. The results showed that many chromosomes affect trabecular bone structure, and that the consomic strain B6-Chr15MSM, carrying MSM/Ms-derived chromosome 15 (Chr15), has the lowest values for the parameters BV/TV, Tb.N, and Conn.D, and the highest values for the parameters Tb.Sp and SMI. Subsequent phenotyping of subconsomic strains for Chr15 mapped four novel trabecular bone structure-related QTL (Tbsq1-4) on mouse Chr15. These results collectively indicate that genetic regulation of trabecular bone structure is highly complex, and that even in the single Chr15, the combined action of the four Tbsqs controls the fragility of trabecular bone. Given that Tbsq4 is syntenic to human Chr 12q12-13.3, where several bone-related SNPs are assigned, further study of Tbsq4 should facilitate our understanding of the genetic regulation of bone formation in humans.
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Akkiraju H, Bonor J, Nohe A. CK2.1, a novel peptide, induces articular cartilage formation in vivo. J Orthop Res 2017; 35:876-885. [PMID: 27312334 PMCID: PMC5522739 DOI: 10.1002/jor.23342] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 06/14/2016] [Indexed: 02/04/2023]
Abstract
Bone morphogenetic protein 2 regulates chondrogenesis and cartilage formation. However, it also induces chondrocyte hypertrophy and cartilage matrix degradation. We recently designed three peptides CK2.1, CK2.2, and CK2.3 that activate the BMP signaling pathways by releasing casein kinase II (CK2) from distinct sites at the bone morphogenetic protein receptor type Ia (BMPRIa). Since BMP2 is a major regulator of chondrogenesis and the peptides activated BMP signaling in a similar way, we evaluated the effect of these peptides on chondrogenesis and cartilage formation. C3H10T1/2 cells were stimulated with CK2.1, CK2.2, and CK2.3 and evaluated for the chondrogenic and osteogenic potential. For chondrogenesis, Alcian blue staining was performed. Additionally, collagen types II and X expression was measured. For osteogenesis, osteocalcin and von Kossa staining were performed. From the three peptides, CK2.1 was the most promising peptide to induce chondrogenesis but not osteogenesis. To investigate the effect of CK2.1 on articular cartilage formation in vivo, we injected CK2.1 into the tail vein of mice. Injection of CK2.1 into the tail vein of mice led to increased articular cartilage formation but not BMD. In sharp contrast, injection of BMP2 led to increased BMD and expression of collagen type X, a marker of chondrocyte hypertrophy. MMP13 expression was unchanged. Our study demonstrates that CK2.1 drives chondrogenesis and cartilage formation without induction of chondrocyte hypertrophy. Peptide CK2.1 may, therefore, be a valuable therapeutic for cartilage degenerative diseases. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:876-885, 2017.
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Affiliation(s)
- Hemanth Akkiraju
- Department of Biological Sciences; University of Delaware; Newark Delaware 19716
| | - Jeremy Bonor
- Department of Biological Sciences; University of Delaware; Newark Delaware 19716
| | - Anja Nohe
- Department of Biological Sciences; University of Delaware; Newark Delaware 19716
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12
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Adams DJ, Rowe DW, Ackert-Bicknell CL. Genetics of aging bone. Mamm Genome 2016; 27:367-80. [PMID: 27272104 DOI: 10.1007/s00335-016-9650-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/24/2016] [Indexed: 01/08/2023]
Abstract
With aging, the skeleton experiences a number of changes, which include reductions in mass and changes in matrix composition, leading to fragility and ultimately an increase of fracture risk. A number of aspects of bone physiology are controlled by genetic factors, including peak bone mass, bone shape, and composition; however, forward genetic studies in humans have largely concentrated on clinically available measures such as bone mineral density (BMD). Forward genetic studies in rodents have also heavily focused on BMD; however, investigations of direct measures of bone strength, size, and shape have also been conducted. Overwhelmingly, these studies of the genetics of bone strength have identified loci that modulate strength via influencing bone size, and may not impact the matrix material properties of bone. Many of the rodent forward genetic studies lacked sufficient mapping resolution for candidate gene identification; however, newer studies using genetic mapping populations such as Advanced Intercrosses and the Collaborative Cross appear to have overcome this issue and show promise for future studies. The majority of the genetic mapping studies conducted to date have focused on younger animals and thus an understanding of the genetic control of age-related bone loss represents a key gap in knowledge.
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Affiliation(s)
- Douglas J Adams
- Department of Orthopaedic Surgery, University of Connecticut Musculoskeletal Institute, University of Connecticut Health, Farmington, CT, 06030, USA
| | - David W Rowe
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, Biomaterials and Skeletal Development, University of Connecticut Health, Farmington, CT, USA
| | - Cheryl L Ackert-Bicknell
- Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Ave, Box 665, Rochester, NY, 14624, USA.
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Goupil BA, McNulty MA, Martin MJ, McCracken MK, Christofferson RC, Mores CN. Novel Lesions of Bones and Joints Associated with Chikungunya Virus Infection in Two Mouse Models of Disease: New Insights into Disease Pathogenesis. PLoS One 2016; 11:e0155243. [PMID: 27182740 PMCID: PMC4868286 DOI: 10.1371/journal.pone.0155243] [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: 01/30/2016] [Accepted: 04/26/2016] [Indexed: 12/13/2022] Open
Abstract
Chikungunya virus is an arbovirus spread predominantly by Aedes aegypti and Ae. albopictus mosquitoes, and causes debilitating arthralgia and arthritis. While these are common manifestations during acute infection and it has been suggested they can recur in patients chronically, gaps in knowledge regarding the pathogenesis still exist. Two established mouse models were utilized (adult IRF 3/7 -/- -/- and wild-type C57BL/6J mice) to evaluate disease manifestations in bones and joints at various timepoints. Novel lesions in C57BL/6J mice consisted of periostitis (91%) and foci of cartilage of necrosis (50% of mice at 21 DPI). Additionally, at 21 DPI, 50% and 75% of mice exhibited periosteal bone proliferation affecting the metatarsal bones, apparent via histology and μCT, respectively. μCT analysis did not reveal any alterations in trabecular bone volume measurements in C57BL/6J mice. Novel lesions demonstrated in IRF 3/7 -/- -/- mice at 5 DPI included focal regions of cartilage necrosis (20%), periosteal necrosis (66%), and multifocal ischemic bone marrow necrosis (100%). Contralateral feet in 100% of mice of both strains had similar, though milder lesions. Additionally, comparison of control IRF 3/7 -/- -/- and wild-type C57BL/6J mice demonstrated differences in cortical bone. These experiments demonstrate novel manifestations of disease similar to those occurring in humans, adding insight into disease pathogenesis, and representing new potential targets for therapeutic interventions. Additionally, results demonstrate the utility of μCT in studies of bone and joint pathology and illustrate differences in bone dynamics between mouse strains.
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Affiliation(s)
- Brad A. Goupil
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana, United States of America
| | - Margaret A. McNulty
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana, United States of America
| | - Matthew J. Martin
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana, United States of America
| | - Michael K. McCracken
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana, United States of America
| | - Rebecca C. Christofferson
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana, United States of America
| | - Christopher N. Mores
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana, United States of America
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14
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High-Resolution Peripheral Quantitative Computed Tomography (HR-PQCT) and Dual Energy X-Ray Absorptiometry (DXA) Measurements of Proximal Tibia in Patients Undergoing Total Knee Arthroplasty. Int Surg 2016. [DOI: 10.9738/intsurg-d-15-00090.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The aim of the study was to assess bone morphometric indices of the proximal tibia and compare it with bone mineral density (BMD) at hip and lumbar spine and compare with the pQCT. Fifty consecutive patients who underwent total knee arthroplasty (TKA) had a dual energy X-ray absorptiometry (DXA) scan of the upper femur and lumbar spine. Upper tibial cuts were harvested from the tibial condyles and a DXA of tibial cuts was done during TKA. Bone morphometry studies were carried out using HR-pQCT. The bone mineral density at the hip was 0.54 ± 0.08 g/cm2 and spine was 0.73 ± 0.1 with a T score at the hip −2.23 ± 0.44 and spine −2.61 ± 0.45. The bone mineral density of the tibial cut was 0.356 ± 0.03 g/cm2 (P < 0.001) and T score was −6.58 ± 2.87 (P < 0.001). The average bone volume (BV) was 115.27 ± 40.45 mm3, trabecular number (Tb.N) was 1.45 ± 0.32 (1.009–2.37) and trabecular thickness (Tb.Th) was 0.181 ± 0.03 mm (0.111–0.268). The mean bone mineral density measured was 206.24 ± 50.58 mg HA/ccm. This study shows that there is highly significant difference between BMD measured by DXA and pQCT, and that bone morphometric analysis indicates that there is marked decrease in the mechanical properties of the bone in the proximal tibia due to knee Osteoarthritis and Osteoporosis indicating poor bone architecture and quality.
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15
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Moran MM, Virdi AS, Sena K, Mazzone SR, McNulty MA, Sumner DR. Intramembranous bone regeneration differs among common inbred mouse strains following marrow ablation. J Orthop Res 2015; 33:1374-81. [PMID: 25808034 DOI: 10.1002/jor.22901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/10/2015] [Indexed: 02/06/2023]
Abstract
Various intact and post-injury bone phenotypes are heritable traits. In this study, we sought to determine if intramembranous bone regeneration following marrow ablation differed among common inbred mouse strains and to identify how early the differences appear. We found a ∼four-fold difference in the regenerated bone volume 21 days after marrow ablation in females from four inbred mouse strains: FVB/N (15.7 ± 8.1%, mean and standard deviation), C3H/He (15.5 ± 4.2%), C57BL/6 (12.2 ± 5.2%), and BALB/c (4.0 ± 4.4%); with BALB/c different from FVB/N (p = 0.007) and C3H/He (p = 0.002). A second experiment showed that FVB/N compared to BALB/c mice had more regenerated bone 7 and 14 days after ablation (p < 0.001), while at 21 days FVB/N mice had a greater fraction of mineralizing surface (p = 0.008) without a difference in mineral apposition rate. Thus, differences among strains are evident early during intramembranous bone regeneration following marrow ablation and appear to be associated with differences in osteogenic cell recruitment, but not osteoblast activity. The amount of regenerating bone was not correlated with other heritable traits such as the intact bone phenotype or soft tissue wound healing, suggesting that there may be independent genetic pathways for these traits.
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Affiliation(s)
- Meghan M Moran
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago
| | - Amarjit S Virdi
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago
| | - Kotaro Sena
- Department of Periodontology, Kagoshima University, Kagoshima, Japan
| | - Steven R Mazzone
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago
| | - Margaret A McNulty
- Department Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge
| | - Dale R Sumner
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago
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16
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High-throughput phenotyping and genetic linkage of cortical bone microstructure in the mouse. BMC Genomics 2015; 16:493. [PMID: 26138817 PMCID: PMC4490749 DOI: 10.1186/s12864-015-1617-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 05/05/2015] [Indexed: 11/16/2022] Open
Abstract
Background Understanding cellular structure and organization, which plays an important role in biological systems ranging from mechanosensation to neural organization, is a complicated multifactorial problem depending on genetics, environmental factors, and stochastic processes. Isolating these factors necessitates the measurement and sensitive quantification of many samples in a reliable, high-throughput, unbiased manner. In this manuscript we present a pipelined approach using a fully automated framework based on Synchrotron-based X-ray Tomographic Microscopy (SRXTM) for performing a full 3D characterization of millions of substructures. Results We demonstrate the framework on a genetic study on the femur bones of in-bred mice. We measured 1300 femurs from a F2 cross experiment in mice without the growth hormone (which can confound many of the smaller structural differences between strains) and characterized more than 50 million osteocyte lacunae (cell-sized hollows in the bone). The results were then correlated with genetic markers in a process called quantitative trait localization (QTL). Our findings provide a mapping between regions of the genome (all 19 autosomes) and observable phenotypes which could explain between 8–40 % of the variance using between 2–10 loci for each trait. This map shows 4 areas of overlap with previous studies looking at bone strength and 3 areas not previously associated with bone. Conclusions The mapping of microstructural phenotypes provides a starting point for both structure-function and genetic studies on murine bone structure and the specific loci can be investigated in more detail to identify single gene candidates which can then be translated to human investigations. The flexible infrastructure offers a full spectrum of shape, distribution, and connectivity metrics for cellular networks and can be adapted to a wide variety of materials ranging from plant roots to lung tissue in studies requiring high sample counts and sensitive metrics such as the drug-gene interactions and high-throughput screening. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1617-y) contains supplementary material, which is available to authorized users.
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17
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Akkiraju H, Bonor J, Olli K, Bowen C, Bragdon B, Coombs H, Donahue LR, Duncan R, Nohe A. Systemic injection of CK2.3, a novel peptide acting downstream of bone morphogenetic protein receptor BMPRIa, leads to increased trabecular bone mass. J Orthop Res 2015; 33:208-15. [PMID: 25331517 PMCID: PMC4304894 DOI: 10.1002/jor.22752] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 09/19/2014] [Indexed: 02/04/2023]
Abstract
Bone Morphogenetic Protein 2 (BMP2) regulates bone integrity by driving both osteogenesis and osteoclastogenesis. However, BMP2 as a therapeutic has significant drawbacks. We have designed a novel peptide CK2.3 that blocks the interaction of Casein Kinase 2 (CK2) with Bone Morphogenetic Protein Receptor type Ia (BMPRIa), thereby activating BMP signaling pathways in the absence of ligand. Here, we show that CK2.3 induced mineralization in primary osteoblast cultures isolated from calvaria and bone marrow stromal cells (BMSCs) of 8 week old mice. Further, systemic tail vein injections of CK2.3 in 8 week old mice resulted in increased bone mineral density (BMD) and mineral apposition rate (MAR). In situ immunohistochemistry of the femur found that CK2.3 injection induced phosphorylation of extracellular signal-related kinase (ERK), but not Smad in osteocytes and osteoblasts, suggesting that CK2.3 signaling occurred through Smad independent pathway. Finally mice injected with CK2.3 exhibited decreased osteoclast differentiation and osteoclast activity. These data indicate that the novel mimetic peptide CK2.3 activated BMPRIa downstream signaling to enhance bone formation without the increase in osteoclast activity that accompanies BMP 2 stimulation.
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Affiliation(s)
- Hemanth Akkiraju
- Department of Biological Sciences, University of Delaware, Newark, DE
| | - Jeremy Bonor
- Department of Biological Sciences, University of Delaware, Newark, DE
| | - Kristine Olli
- Department of Biological Sciences, University of Delaware, Newark, DE
| | - Chris Bowen
- Department of Biological Sciences, University of Delaware, Newark, DE
| | | | | | | | - Randall Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE
| | - Anja Nohe
- Department of Biological Sciences, University of Delaware, Newark, DE,to whom should be corresponded.
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18
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Ozcivici E, Zhang W, Donahue LR, Judex S. Quantitative trait loci that modulate trabecular bone's risk of failure during unloading and reloading. Bone 2014; 64:25-32. [PMID: 24698783 DOI: 10.1016/j.bone.2014.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 02/01/2014] [Accepted: 03/22/2014] [Indexed: 01/23/2023]
Abstract
Genetic makeup of an individual is a strong determinant of the morphologic and mechanical properties of bone. Here, in an effort to identify quantitative trait loci (QTLs) for changes in the simulated mechanical parameters of trabecular bone during altered mechanical demand, we subjected 352 second generation female adult (16 weeks old) BALBxC3H mice to 3 weeks of hindlimb unloading followed by 3 weeks of reambulation. Longitudinal in vivo microcomputed tomography (μCT) scans tracked trabecular changes in the distal femur. Tomographies were directly translated into finite element (FE) models and subjected to a uniaxial compression test. Apparent trabecular stiffness and components of the Von Mises (VM) stress distributions were computed for the distal metaphysis and associated with QTLs. At baseline, five QTLs explained 20% of the variation in trabecular peak stresses across the mouse population. During unloading, three QTLs accounted for 14% of the variability in peak stresses. During reambulation, one QTL accounted for 5% of the variability in peak stresses. QTLs were also identified for mechanically induced changes in stiffness, median stress values and skewness of stress distributions. There was little overlap between QTLs identified for baseline and QTLs for longitudinal changes in mechanical properties, suggesting that distinct genes may be responsible for the mechanical response of trabecular bone. Unloading related QTLs were also different from reambulation related QTLs. Further, QTLs identified here for mechanical properties differed from previously identified QTLs for trabecular morphology, perhaps revealing novel gene targets for reducing fracture risk in individuals exposed to unloading and for maximizing the recovery of trabecular bone's mechanical properties during reambulation.
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Affiliation(s)
- Engin Ozcivici
- Department of Mechanical Engineering, Izmir Institute of Technology, Urla, Izmir 35430, Turkey.
| | | | | | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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19
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McGee-Lawrence ME, Ryan ZC, Carpio LR, Kakar S, Westendorf JJ, Kumar R. Sclerostin deficient mice rapidly heal bone defects by activating β-catenin and increasing intramembranous ossification. Biochem Biophys Res Commun 2013; 441:886-90. [PMID: 24211207 DOI: 10.1016/j.bbrc.2013.10.155] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 10/29/2013] [Indexed: 11/19/2022]
Abstract
We investigated the influence of the osteocyte protein, sclerostin, on fracture healing by examining the dynamics and mechanisms of repair of single-cortex, stabilized femoral defects in sclerostin knockout (Sost(-/-); KO) and sclerostin wild-type (Sost(+/+); WT) mice. Fourteen days following generation of bone defects, Sost KO mice had significantly more bone in the healing defect than WT mice. The increase in regenerating bone was due to an increase in the thickness of trabecularized spicules, osteoblast numbers and surfaces within the defect. Enhanced healing of bone defects in Sost KO mice was associated with significantly more activated β-catenin expression than observed in WT mice. The findings were similar to those observed in Axin2(-/-) mice, in which β-catenin signaling is known to be enhanced to facilitate bone regeneration. Taken together, these data indicate that enhanced β-catenin signaling is present in Sost(-/-) mice that demonstrate accelerated healing of bone defects, suggesting that modulation of β-catenin signaling in bone could be used to promote fracture repair.
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Affiliation(s)
- Meghan E McGee-Lawrence
- Department of Orthopedic Surgery, Mayo Clinic College of Medicine, Mayo Clinic, 200 1st St., Southwest, Rochester, MN 55905, USA
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20
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Fleckman P, Jaeger K, Silva KA, Sundberg JP. Comparative anatomy of mouse and human nail units. Anat Rec (Hoboken) 2013; 296:521-32. [PMID: 23408541 DOI: 10.1002/ar.22660] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/10/2012] [Accepted: 12/17/2012] [Indexed: 12/15/2022]
Abstract
Recent studies of mice with hair defects have resulted in major contributions to the understanding of hair disorders. To use mouse models as a tool to study nail diseases, a basic understanding of the similarities and differences between the human and mouse nail unit is required. In this study we compare the human and mouse nail unit at the macroscopic and microscopic level and use immunohistochemistry to determine the keratin expression patterns in the mouse nail unit. Both species have a proximal nail fold, cuticle, nail matrix, nail bed, nail plate, and hyponychium. Distinguishing features are the shape of the nail and the presence of an extended hyponychium in the mouse. Expression patterns of most keratins are similar. These findings indicate that the mouse nail unit shares major characteristics with the human nail unit and overall represents a very similar structure, useful for the investigation of nail diseases and nail biology.
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Affiliation(s)
- Philip Fleckman
- Department of Medicine, Division of Dermatology, University of Washington, Seattle, Washington, DC 98195-6524, USA
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21
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Ruffoni D, Kohler T, Voide R, Wirth AJ, Donahue LR, Müller R, van Lenthe GH. High-throughput quantification of the mechanical competence of murine femora--a highly automated approach for large-scale genetic studies. Bone 2013; 55:216-21. [PMID: 23486181 DOI: 10.1016/j.bone.2013.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/25/2013] [Accepted: 02/18/2013] [Indexed: 10/27/2022]
Abstract
Animal models are widely used to gain insight into the role of genetics on bone structure and function. One of the main strategies to map the genes regulating specific traits is called quantitative trait loci (QTL) analysis, which generally requires a very large number of animals (often more than 1000) to reach statistical significance. QTL analysis for mechanical traits has been mainly based on experimental mechanical testing, which, in view of the large number of animals, is time consuming. Hence, the goal of the present work was to introduce an automated method for large-scale high-throughput quantification of the mechanical properties of murine femora. Specifically, our aims were, first, to develop and validate an automated method to quantify murine femoral bone stiffness. Second, to test its high-throughput capabilities on murine femora from a large genetic study, more specifically, femora from two growth hormone (GH) deficient inbred strains of mice (B6-lit/lit and C3.B6-lit/lit) and their first (F1) and second (F2) filial offsprings. Automated routines were developed to convert micro-computed tomography (micro-CT) images of femora into micro-finite element (micro-FE) models. The method was experimentally validated on femora from C57BL/6J and C3H/HeJ mice: for both inbred strains the micro-FE models closely matched the experimentally measured bone stiffness when using a single tissue modulus of 13.06 GPa. The mechanical analysis of the entire dataset (n=1990) took approximately 44 CPU hours on a supercomputer. In conclusion, our approach, in combination with QTL analysis could help to locate genes directly involved in controlling bone mechanical competence.
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Affiliation(s)
- D Ruffoni
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.
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22
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Gualdrón Duarte JL, Bates RO, Ernst CW, Raney NE, Cantet RJC, Steibel JP. Genotype imputation accuracy in a F2 pig population using high density and low density SNP panels. BMC Genet 2013; 14:38. [PMID: 23651538 PMCID: PMC3655050 DOI: 10.1186/1471-2156-14-38] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 04/13/2013] [Indexed: 01/18/2023] Open
Abstract
Background F2 resource populations have been used extensively to map QTL segregating between pig breeds. A limitation associated with the use of these resource populations for fine mapping of QTL is the reduced number of founding individuals and recombinations of founding haplotypes occurring in the population. These limitations, however, become advantageous when attempting to impute unobserved genotypes using within family segregation information. A trade-off would be to re-type F2 populations using high density SNP panels for founding individuals and low density panels (tagSNP) in F2 individuals followed by imputation. Subsequently a combined meta-analysis of several populations would provide adequate power and resolution for QTL mapping, and could be achieved at relatively low cost. Such a strategy allows the wealth of phenotypic information that has previously been obtained on experimental resource populations to be further mined for QTL identification. In this study we used experimental and simulated high density genotypes (HD-60K) from an F2 cross to estimate imputation accuracy under several genotyping scenarios. Results Selection of tagSNP using physical distance or linkage disequilibrium information produced similar imputation accuracies. In particular, tagSNP sets averaging 1 SNP every 2.1 Mb (1,200 SNP genome-wide) yielded imputation accuracies (IA) close to 0.97. If instead of using custom panels, the commercially available 9K chip is used in the F2, IA reaches 0.99. In order to attain such high imputation accuracy the F0 and F1 generations should be genotyped at high density. Alternatively, when only the F0 is genotyped at HD, while F1 and F2 are genotyped with a 9K panel, IA drops to 0.90. Conclusions Combining 60K and 9K panels with imputation in F2 populations is an appealing strategy to re-genotype existing populations at a fraction of the cost.
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23
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Sclerostin alters serum vitamin D metabolite and fibroblast growth factor 23 concentrations and the urinary excretion of calcium. Proc Natl Acad Sci U S A 2013; 110:6199-204. [PMID: 23530237 DOI: 10.1073/pnas.1221255110] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Inactivating mutations of the SOST (sclerostin) gene are associated with overgrowth and sclerosis of the skeleton. To determine mechanisms by which increased amounts of calcium and phosphorus are accreted to enable enhanced bone mineralization in the absence of sclerostin, we measured concentrations of calciotropic and phosphaturic hormones, and urine and serum calcium and inorganic phosphorus in mice in which the sclerostin (sost) gene was replaced by the β-D-galactosidase (lacZ) gene in the germ line. Knockout (KO) (sost(-/-)) mice had increased bone mineral density and content, increased cortical and trabecular bone thickness, and greater net bone formation as a result of increased osteoblast and decreased osteoclast surfaces compared with wild-type (WT) mice. β-Galactosidase activity was detected in osteocytes of sost KO mice but was undetectable in WT mice. Eight-week-old, male sost KO mice had increased serum 1α,25-dihydroxyvitamin D, decreased 24,25-dihydroxyvitamin D, decreased intact fibroblast growth factor 23, and elevated inorganic phosphorus concentrations compared with age-matched WT mice. 25-Hydroxyvitamin D 1α-hydroxylase cytochrome P450 (cyp27B1) mRNA was increased in kidneys of sost KO mice compared with WT mice. Treatment of cultured proximal tubule cells with mouse recombinant sclerostin decreased cyp27B1 mRNA transcripts. Urinary calcium and renal fractional excretion of calcium were decreased in sost KO mice compared with WT mice. Sost KO and WT mice had similar serum calcium and parathyroid hormone concentrations. The data show that sclerostin not only alters bone mineralization, but also influences mineral metabolism by altering concentrations of hormones that regulate mineral accretion.
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24
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Carson EA, Kenney-Hunt JP, Pavlicev M, Bouckaert KA, Chinn AJ, Silva MJ, Cheverud JM. Weak genetic relationship between trabecular bone morphology and obesity in mice. Bone 2012; 51:46-53. [PMID: 22503703 PMCID: PMC3371175 DOI: 10.1016/j.bone.2012.03.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
Obesity, in addition to being associated with metabolic diseases, such as diabetes, has also been found to lower the risk of osteoporotic fractures. The relationship between obesity and bone trabecular structure is complex, involving responses to mechanical loading and the effects of adipocyte-derived hormones, both directly interacting with bone tissue and indirectly through central nervous system signaling. Here we examine the effects of sex, a high fat diet, and genetics on the trabecular density and structure of the lumbar and caudal vertebra and the proximal tibia along with body weight, fat pad weight, and serum leptin levels in a murine obesity model, the LGXSM recombinant inbred (RI) mouse strains. The sample included 481 mice from 16 RI strains. We found that vertebral trabecular density was higher in males while the females had higher tibial trabecular density. The high fat diet led to only slightly higher trabecular density in both sexes despite its extreme effects on obesity and serum leptin levels. Trait heritabilities are moderate to strong and genetic correlations among trabecular features are high. Most genetic variation contrasts strains with large numbers of thick, closely-spaced, highly interconnected, plate-like trabeculae with a high bone volume to total volume ratio against strains displaying small numbers of thin, widely-spaced, sparsely connected, rod-like trabeculae with a low bone volume to total volume ratio. Genetic correlations between trabecular and obesity-related traits were low and not statistically significant. We mapped trabecular properties to 20 genomic locations. Only one-quarter of these locations also had effects on obesity. In this population obesity has a relatively minor effect on trabecular bone morphology.
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Affiliation(s)
- E Ann Carson
- Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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25
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Farber CR, Kelly SA, Baruch E, Yu D, Hua K, Nehrenberg DL, de Villena FPM, Buus RJ, Garland T, Pomp D. Identification of quantitative trait loci influencing skeletal architecture in mice: emergence of Cdh11 as a primary candidate gene regulating femoral morphology. J Bone Miner Res 2011; 26:2174-83. [PMID: 21638317 PMCID: PMC3304441 DOI: 10.1002/jbmr.436] [Citation(s) in RCA: 20] [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] [Indexed: 01/23/2023]
Abstract
Bone strength is influenced by many properties intrinsic to bone, including its mass, geometry, and mineralization. To further advance our understanding of the genetic basis of bone-strength-related traits, we used a large (n = 815), moderately (G(4) ) advanced intercross line (AIL) of mice derived from a high-runner selection line (HR) and the C57BL/6J inbred strain. In total, 16 quantitative trait loci (QTLs) were identified that affected areal bone mineral density (aBMD) and femoral length and width. Four significant (p < .05) and one suggestive (p < .10) QTLs were identified for three aBMD measurements: total body, vertebral, and femoral. A QTL on chromosome (Chr.) 3 influenced all three aBMD measures, whereas the other four QTLs were unique to a single measure. A total of 10 significant and one suggestive QTLs were identified for femoral length (FL) and two measures of femoral width, anteroposterior (AP) and mediolateral (ML). FL QTLs were distinct from loci affecting AP and ML width, and of the 7 AP QTLs, only three affected ML. A QTL on Chr. 8 that explained 7.1% and 4.0% of the variance in AP and ML, respectively, was mapped to a 6-Mb region harboring 12 protein-coding genes. The pattern of haplotype diversity across the QTL region and expression profiles of QTL genes suggested that of the 12, cadherin 11 (Cdh11) was most likely the causal gene. These findings, when combined with existing data from gene knockouts, identify Cdh11 as a strong candidate gene within which genetic variation may affect bone morphology.
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Affiliation(s)
- Charles R Farber
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA.
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26
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Lagerholm S, Park HB, Luthman H, Grynpas M, McGuigan F, Swanberg M, Åkesson K. Identification of candidate gene regions in the rat by co-localization of QTLs for bone density, size, structure and strength. PLoS One 2011; 6:e22462. [PMID: 21818327 PMCID: PMC3144887 DOI: 10.1371/journal.pone.0022462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/25/2011] [Indexed: 12/05/2022] Open
Abstract
Susceptibility to osteoporotic fracture is influenced by genetic factors that can be dissected by whole-genome linkage analysis in experimental animal crosses. The aim of this study was to characterize quantitative trait loci (QTLs) for biomechanical and two-dimensional dual-energy X-ray absorptiometry (DXA) phenotypes in reciprocal F2 crosses between diabetic GK and normo-glycemic F344 rat strains and to identify possible co-localization with previously reported QTLs for bone size and structure. The biomechanical measurements of rat tibia included ultimate force, stiffness and work to failure while DXA was used to characterize tibial area, bone mineral content (BMC) and areal bone mineral density (aBMD). F2 progeny (108 males, 98 females) were genotyped with 192 genome-wide markers followed by sex- and reciprocal cross-separated whole-genome QTL analyses. Significant QTLs were identified on chromosome 8 (tibial area; logarithm of odds (LOD) = 4.7 and BMC; LOD = 4.1) in males and on chromosome 1 (stiffness; LOD = 5.5) in females. No QTLs showed significant sex-specific interactions. In contrast, significant cross-specific interactions were identified on chromosome 2 (aBMD; LOD = 4.7) and chromosome 6 (BMC; LOD = 4.8) for males carrying F344mtDNA, and on chromosome 15 (ultimate force; LOD = 3.9) for males carrying GKmtDNA, confirming the effect of reciprocal cross on osteoporosis-related phenotypes. By combining identified QTLs for biomechanical-, size- and qualitative phenotypes (pQCT and 3D CT) from the same population, overlapping regions were detected on chromosomes 1, 3, 4, 6, 8 and 10. These are strong candidate regions in the search for genetic risk factors for osteoporosis.
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Affiliation(s)
- Sofia Lagerholm
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Hee-Bok Park
- Medical Genetics Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Holger Luthman
- Medical Genetics Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Marc Grynpas
- Institute of Biomaterials and Biomedical Engineering, University of Toronto and Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Canada
| | - Fiona McGuigan
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Maria Swanberg
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Kristina Åkesson
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
- Department of Orthopedics, Skåne University Hospital Malmö, Malmö, Sweden
- * E-mail:
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Zmuda JM, Yerges-Armstrong LM, Moffett SP, Klei L, Kammerer CM, Roeder K, Cauley JA, Kuipers A, Ensrud KE, Nestlerode CS, Hoffman AR, Lewis CE, Lang TF, Barrett-Connor E, Ferrell RE, Orwoll ES. Genetic analysis of vertebral trabecular bone density and cross-sectional area in older men. Osteoporos Int 2011; 22:1079-90. [PMID: 21153022 PMCID: PMC3691107 DOI: 10.1007/s00198-010-1296-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 04/13/2010] [Indexed: 12/21/2022]
Abstract
UNLABELLED We investigated 383 bone candidate genes for associations between single nucleotide polymorphisms and vertebral trabecular volumetric bone mineral density (vBMD) and cross-sectional area (CSA) in 2,018 Caucasian men aged ≥ 65 years. SNPs in TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE were associated with vBMD and SNPs in CYP11B1, DVL2, DLX5, WNT4, and PAX7 were associated with CSA in independent study samples (p < 0.005). INRODUCTION Vertebral bone mineral density and cross-sectional area are important determinants of vertebral bone strength. Little is known about the specific genetic variants that influence these phenotypes in humans. METHODS We investigated the potential genetic variants associated with vertebral trabecular volumetric BMD and CSA measured by quantitative computed tomography. We initially tested for association between these phenotypes and 4608 tagging and potentially functional single nucleotide polymorphisms (SNPs) in 383 candidate genes in 862 community-dwelling Caucasian men aged ≥ 65 years in the Osteoporotic Fractures in Men Study. RESULTS SNP associations were then validated by genotyping an additional 1,156 randomly sampled men from the same cohort. We identified 11 SNPs in 10 genes (TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE) that were consistently associated with trabecular vBMD and five SNPs in five genes (CYP11B1, DVL2, DLX5, WNT4, and PAX7) that were consistently associated with CSA in both samples (p < 0.005). CONCLUSION None of the SNPs associated with trabecular vBMD were associated with CSA. Our findings raise the possibility that at least some of the loci for vertebral trabecular BMD and bone size may be distinct.
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Affiliation(s)
- J M Zmuda
- Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
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Lagerholm S, Park HB, Luthman H, Nilsson M, McGuigan F, Swanberg M, Akesson K. Genetic loci for bone architecture determined by three-dimensional CT in crosses with the diabetic GK rat. Bone 2010; 47:1039-47. [PMID: 20699128 DOI: 10.1016/j.bone.2010.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 07/30/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
Abstract
The F344 rat carries alleles contributing to bone fragility while the GK rat spontaneously develops type-2 diabetes. These characteristics make F344×GK crosses well suited for the identification of genes related to bone size and allow for future investigation on the association with type-2 diabetes. The aim of this study was to identify quantitative trait loci (QTLs) for bone size phenotypes measured by a new application of three-dimensional computed tomography (3DCT) and to investigate the effects of sex- and reciprocal cross. Tibia from male and female GK and F344 rats, representing the parental, F1 and F2 generations, were examined with 3DCT and analyzed for: total and cortical volumetric BMD, straight and curved length, peri- and endosteal area at mid-shaft. F2 progeny (108 male and 98 female) were genotyped with 192 genome-wide microsatellite markers (average distance 10 cM). Sex- and reciprocal cross-separated QTL analyses were performed for the identification of QTLs linked to 3DCT phenotypes and true interactions were confirmed by likelihood ratio analysis in all F2 animals. Several genome-wide significant QTLs were found in the sex- and reciprocal cross-separated progeny on chromosomes (chr) 1, 3, 4, 9, 10, 14, and 17. Overlapping QTLs for both males and females in the (GK×F344)F2 progeny were located on chr 1 (39-67 cM). This region confirms previously reported pQCT QTLs and overlaps loci for fasting glucose. Sex separated linkage analysis confirmed a male specific QTL on chr 9 (67-82 cM) for endosteal area at the fibula site. Analyses separating the F2 population both by sex and reciprocal cross identified cross specific QTLs on chr 14 (males) and chr 3 and 4 (females). Two loci, chr 4 and 6, are unique to 3DCT and separate from pQCT generated loci. The 3DCT method was highly reproducible and provided high precision measurements of bone size in the rat enabling identification of new sex- and cross-specific loci. The QTLs on chr 1 indicate potential genetic association between bone-related phenotypes and traits affecting type-2 diabetes. The results illustrate the complexity of the genetic architecture of bone size phenotypes and demonstrate the importance of complementary methods for bone analysis.
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Affiliation(s)
- Sofia Lagerholm
- Lund University, Department of Clinical Sciences-Malmö, Clinical and Molecular Osteoporosis Unit, Malmö, Sweden.
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Everett ET. Fluoride's effects on the formation of teeth and bones, and the influence of genetics. J Dent Res 2010; 90:552-60. [PMID: 20929720 DOI: 10.1177/0022034510384626] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Fluorides are present in the environment. Excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis (skeletal fluorosis) and enamel development (dental/enamel fluorosis). The severity of dental fluorosis is also dependent upon fluoride dose and the timing and duration of fluoride exposure. Fluoride's actions on bone cells predominate as anabolic effects both in vitro and in vivo. More recently, fluoride has been shown to induce osteoclastogenesis in mice. Fluorides appear to mediate their actions through the MAPK signaling pathway and can lead to changes in gene expression, cell stress, and cell death. Different strains of inbred mice demonstrate differential physiological responses to ingested fluoride. Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations. Ultimately, this can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization.
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Affiliation(s)
- E T Everett
- Department of Pediatric Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, 228 Brauer Hall, CB# 7450, Chapel Hill, NC 27599, USA.
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Craft CS, Zou W, Watkins M, Grimston S, Brodt MD, Broekelmann TJ, Weinbaum JS, Teitelbaum SL, Pierce RA, Civitelli R, Silva MJ, Mecham RP. Microfibril-associated glycoprotein-1, an extracellular matrix regulator of bone remodeling. J Biol Chem 2010; 285:23858-67. [PMID: 20501659 PMCID: PMC2911322 DOI: 10.1074/jbc.m110.113019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 04/30/2010] [Indexed: 01/11/2023] Open
Abstract
MAGP1 is an extracellular matrix protein that, in vertebrates, is a ubiquitous component of fibrillin-rich microfibrils. We previously reported that aged MAGP1-deficient mice (MAGP1Delta) develop lesions that are the consequence of spontaneous bone fracture. We now present a more defined bone phenotype found in MAGP1Delta mice. A longitudinal DEXA study demonstrated age-associated osteopenia in MAGP1Delta animals and muCT confirmed reduced bone mineral density in the trabecular and cortical bone. Further, MAGP1Delta mice have significantly less trabecular bone, the trabecular microarchitecture is more fragmented, and the diaphyseal cross-sectional area is significantly reduced. The remodeling defect seen in MAGP1Delta mice is likely not due to an osteoblast defect, because MAGP1Delta bone marrow stromal cells undergo osteoblastogenesis and form mineralized nodules. In vivo, MAGP1Delta mice exhibit normal osteoblast number, mineralized bone surface, and bone formation rate. Instead, our findings suggest increased bone resorption is responsible for the osteopenia. The number of osteoclasts derived from MAGP1Delta bone marrow macrophage cells is increased relative to the wild type, and osteoclast differentiation markers are expressed at earlier time points in MAGP1Delta cells. In vivo, MAGP1Delta mice have more osteoclasts lining the bone surface. RANKL (receptor activator of NF-kappaB ligand) expression is significantly higher in MAGP1Delta bone, and likely contributes to enhanced osteoclastogenesis. However, bone marrow macrophage cells from MAGP1Delta mice show a higher propensity than do wild-type cells to differentiate to osteoclasts in response to RANKL, suggesting that they are also primed to respond to osteoclast-promoting signals. Together, our findings suggest that MAGP1 is a regulator of bone remodeling, and its absence results in osteopenia associated with an increase in osteoclast number.
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Affiliation(s)
| | - Wei Zou
- Anatomic and Molecular Pathology
| | | | | | - Michael D. Brodt
- Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110 and
| | | | - Justin S. Weinbaum
- the Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455
| | | | | | | | - Matthew J. Silva
- Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110 and
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Jiao F, Chiu H, Jiao Y, de Rijk WG, Li X, Eckstein EC, Beamer WG, Gu W. Quantitative trait loci for tibial bone strength in C57BL/6J and C3H/HeJ inbred strains of mice. J Genet 2010; 89:21-7. [PMID: 20505243 DOI: 10.1007/s12041-010-0007-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Three-point bending technology has been widely used in the measurement of bone strength. Quantitative trait loci (QTLs) for bone strength have been identified using mouse femurs. In this study, we investigate the use of mouse tibiae in identification of QTLs that regulate bone strength. Mouse tibiae were from a F(2) population derived from C57BL/6J (B6) and C3H/HeJ (C3H). Three-point bending was measured using ISO 4049, with the support width adjustable to accommodate specimen sizes outside the scope of ISO 4049. The strain rate is selectable from 0.05 to 500 mm per min. All stress strain diagrams are recorded and retrieved in digital electronic form. Genome scan was performed in The Jackson Laboratory (TJL). QTL mapping was conducted using Map Manager QTX software. Data show that (i) both elastic modulus (stiffness) and maximum loading (strength) value appear as normal distributions, suggesting that multiple genetic factors control the bone strength; (ii) 11 QTLs, accounting for 90% of variation for strength, have been detected. More than half QTLs of three-point bending are located on the same locations of bone density earlier identified from mouse femurs; (iii) a major QTL of femoral and vertebral bone mineral density (BMD) was not detected for bone strength of tibiae; (iv) the QTL on chromosome 4 has extremely high LOD score of 31.8 and represents 60% of the variation of bone strength; and (v) four QTLs of stiffness (chromosomes 2, 11, 15 and 19) have been identified.
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Affiliation(s)
- Feng Jiao
- Department of Orthopedic Surgery-Campbell Clinic, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Moisan MP. Genotype-phenotype associations in understanding the role of corticosteroid-binding globulin in health and disease animal models. Mol Cell Endocrinol 2010; 316:35-41. [PMID: 19643164 DOI: 10.1016/j.mce.2009.07.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 07/09/2009] [Accepted: 07/09/2009] [Indexed: 10/20/2022]
Abstract
Corticosteroid-binding globulin (CBG) is a plasma glycoprotein discovered more than 60 years ago for its high-affinity for glucocorticoids. Although its molecular structure and its biochemical properties have been described, its various biological roles and its importance are not yet fully understood. This review focuses first on studies that have used no-hypothesis-driven genetic approaches in animal models to reveal the higher than expected importance of CBG in particular in glucocorticoid stress responses. Then the dissection of some CBG physiological roles in an animal model of genetic CBG deficiency is reported. Finally, studies on the role of CBG genetic variability in human obesity traits are reviewed and discussed.
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Affiliation(s)
- Marie-Pierre Moisan
- INRA, UMR 1286 PsyNuGen, CNRS 5226, Universite de Bordeaux 2, Bordeaux, France.
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Abstract
In contrast to conventional dual-energy X-ray absorptiometry, quantitative computed tomography separately measures trabecular and cortical volumetric bone mineral density (vBMD). Little is known about the genetic variants associated with trabecular and cortical vBMD in humans, although both may be important for determining bone strength and osteoporotic risk. In the current analysis, we tested the hypothesis that there are genetic variants associated with trabecular and cortical vBMD at the femoral neck by genotyping 4608 tagging and potentially functional single-nucleotide polymorphisms (SNPs) in 383 bone metabolism candidate genes in 822 Caucasian men aged 65 years or older from the Osteoporotic Fractures in Men Study (MrOS). Promising SNP associations then were tested for replication in an additional 1155 men from the same study. We identified SNPs in five genes (IFNAR2, NFATC1, SMAD1, HOXA, and KLF10) that were robustly associated with cortical vBMD and SNPs in nine genes (APC, ATF2, BMP3, BMP7, FGF18, FLT1, TGFB3, THRB, and RUNX1) that were robustly associated with trabecular vBMD. There was no overlap between genes associated with cortical vBMD and trabecular vBMD. These findings identify novel genetic variants for cortical and trabecular vBMD and raise the possibility that some genetic loci may be unique for each bone compartment.
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Canalis E, Smerdel-Ramoya A, Durant D, Economides AN, Beamer WG, Zanotti S. Nephroblastoma overexpressed (Nov) inactivation sensitizes osteoblasts to bone morphogenetic protein-2, but nov is dispensable for skeletal homeostasis. Endocrinology 2010; 151:221-33. [PMID: 19934377 PMCID: PMC2803142 DOI: 10.1210/en.2009-0574] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Overexpression of nephroblastoma overexpressed (Nov), a member of the Cyr 61, connective tissue growth factor, Nov family of proteins, inhibits osteoblastogenesis and causes osteopenia. The consequences of Nov inactivation on osteoblastogenesis and the postnatal skeleton are not known. To study the function of Nov, we inactivated Nov by homologous recombination. Nov null mice were maintained in a C57BL/6 genetic background after the removal of the neomycin selection cassette and compared with wild-type controls of identical genetic composition. Nov null mice were identified by genotyping and absent Nov mRNA in calvarial extracts and osteoblast cultures. Nov null mice did not exhibit developmental skeletal abnormalities or postnatal changes in weight, femoral length, body fat, or bone mineral density and appeared normal. Bone volume and trabecular number were decreased only in 1-month-old female mice. In older mice, after 7 months of age, osteoblast surface and bone formation were increased in females, and osteoclast and eroded surfaces were increased in male Nov null mice. Calvarial osteoblasts from Nov null mice displayed enhanced alkaline phosphatase activity, alkaline phosphatase mRNA, and transactivation of a bone morphogenetic protein (BMP)/phosphorylated mothers against decapentaplegic reporter construct in response to BMP-2. Similar results were obtained after the down-regulation of Nov by RNA interference in ST-2 stromal and MC3T3 cells. Osteoclast number was increased in marrow stromal cell cultures from Nov null mice. Surface plasmon resonance demonstrated direct interactions between Nov and BMP-2. In conclusion, Nov sensitizes osteoblasts to BMP-2, but Nov is dispensable for the maintenance of bone mass.
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Affiliation(s)
- Ernesto Canalis
- Department of Research, Saint Francis Hospital and Medical Center, 114 Woodland Street, Hartford, Connecticut 06105-1299, USA.
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Hansen HL, Bredbenner TL, Nicolella DP, Mahaney MC, Havill LM. Cross-sectional geometry of the femoral midshaft in baboons is heritable. Bone 2009; 45:892-7. [PMID: 19523547 PMCID: PMC3014089 DOI: 10.1016/j.bone.2009.05.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 05/08/2009] [Accepted: 05/29/2009] [Indexed: 11/20/2022]
Abstract
A great deal of research into the determinants of bone strength has unequivocally demonstrated that variation in bone strength is highly subject to genetic factors. Increasing attention in skeletal genetic studies is being paid to indicators of bone quality that complement studies of BMD, including studies of the genetic control of bone geometry. The aim of this study is to investigate the degree to which normal population-level variation in femoral midshaft geometry in a population of pedigreed baboons (Papio hamadryas spp.) can be attributed to the additive effect of genes. Using 110 baboons (80 females, 30 males), we 1) characterize normal variation in midshaft geometry of the femur with regard to age and sex, and 2) determine the degree to which the residual variation is attributable to additive genetic effects. Cross-sectional area (CSA), minimum (I(MIN)) and maximum (I(MAX)) principal moments of inertia, and polar moment of inertia (J) were calculated from digitized images of transverse midshaft sections. Maximum likelihood-based variance decomposition methods were used to estimate the mean effects of age, sex, and genes. Together age and sex effects account for approximately 56% of the variance in each property. In each case the effect of female sex is negative and that of age is positive, although of a lower magnitude than the effect of female sex. Increased age is associated with decreased mean cross-sectional geometry measures in the oldest females. Residual h(2) values range from 0.36 to 0.50, reflecting genetic effects accounting for 15% to 23% of the total phenotypic variance in individual properties. This study establishes the potential of the baboon model for the identification of genes that regulate bone geometric properties in primates. This model is particularly valuable because it allows for experimental designs, environmental consistency, availability of tissues, and comprehensive assessments of multiple integrated bone phenotypes that are not possible in human populations. The baboon is of particular importance in genetic studies, because it provides results that are likely highly relevant to the human condition due to the phylogenetic proximity of baboons to humans.
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Affiliation(s)
- Heather L. Hansen
- Department of Anthropology, Indiana University, Bloomington, IN 47408
| | - Todd L. Bredbenner
- Department of Materials Engineering, Southwest Research Institute San Antonio, TX 78238
| | - Daniel P. Nicolella
- Department of Materials Engineering, Southwest Research Institute San Antonio, TX 78238
| | - Michael C. Mahaney
- Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX 78245-0549
- Southwest National Primate Research Center, San Antonio, TX 78227
| | - Lorena M. Havill
- Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX 78245-0549
- Corresponding Author: Dr. Lorena M. Havill, Department of Genetics, Southwest Foundation for Biomedical Research, P.O. Box 760549, San Antonio, Texas 78245-0549, Telephone: 210-258-9875, Fax: 210-670-3344,
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Abstract
With recent advances in molecular medicine and disease treatment in osteoporosis, quantitative image processing of three-dimensional bone structures is critical in the context of bone quality assessment. Biomedical imaging technology such as MRI or CT is readily available, but few attempts have been made to expand the capabilities of these systems by integrating quantitative analysis tools and by exploring structure-function relationships in a hierarchical fashion. Nevertheless, such quantitative end points are an important factor for success in basic research and in the development of novel therapeutic strategies. CT is key to these developments, as it images and quantifies bone in three dimensions and provides multiscale biological imaging capabilities with isotropic resolutions of a few millimeters (clinical CT), a few tens of micrometers (microCT) and even as high as 100 nanometers (nanoCT). The technology enables the assessment of the relationship between microstructural and ultrastructural measures of bone quality and certain diseases or therapies. This Review focuses on presenting strategies for three-dimensional approaches to hierarchical biomechanical imaging in the study of microstructural and ultrastructural bone failure. From this Review, it can be concluded that biomechanical imaging is extremely valuable for the study of bone failure mechanisms at different hierarchical levels.
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Affiliation(s)
- Ralph Müller
- Institute for Biomechanics, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, Switzerland.
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Serum IGF-1 determines skeletal strength by regulating subperiosteal expansion and trait interactions. J Bone Miner Res 2009; 24:1481-92. [PMID: 19257833 PMCID: PMC2718800 DOI: 10.1359/jbmr.090226] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Strong correlations between serum IGF-1 levels and fracture risk indicate that IGF-1 plays a critical role in regulating bone strength. However, the mechanism by which serum IGF-1 regulates bone structure and fracture resistance remains obscure and cannot be determined using conventional approaches. Previous analysis of adult liver-specific IGF-1-deficient (LID) mice, which exhibit 75% reductions in serum IGF-1 levels, showed reductions in periosteal circumference, femoral cross-sectional area, cortical thickness, and total volumetric BMD. Understanding the developmental sequences and the resultant anatomical changes that led to this adult phenotype is the key for understanding the complex relationship between serum IGF-1 levels and fracture risk. Here, we identified a unique developmental pattern of morphological and compositional traits that contribute to bone strength. We show that reduced bone strength associated with low levels of IGF-1 in serum (LID mice) result in impaired subperiosteal expansion combined with impaired endosteal apposition and lack of compensatory changes in mineralization throughout growth and aging. We show that serum IGF-1 affects cellular activity differently depending on the cortical surface. Last, we show that chronic reductions in serum IGF-1 indirectly affect bone strength through its effect on the marrow myeloid progenitor cell population. We conclude that serum IGF-1 not only regulates bone size, shape, and composition during ontogeny, but it plays a more fundamental role-that of regulating an individual's ability to adapt its bone structure to mechanical loads during growth and development.
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Zagorchev L, Mulligan-Kehoe MJ. Molecular imaging of vessels in mouse models of disease. Eur J Radiol 2009; 70:305-11. [PMID: 19304428 PMCID: PMC2757633 DOI: 10.1016/j.ejrad.2009.01.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/14/2009] [Indexed: 12/29/2022]
Abstract
Vascular imaging of angiogenesis in mouse models of disease requires multi modal imaging hardware capable of targeting both structure and function at different physical scales. The three dimensional (3D) structure and function vascular information allows for accurate differentiation between biological processes. For example, image analysis of vessel development in angiogenesis vs. arteriogenesis enables more accurate detection of biological variation between subjects and more robust and reliable diagnosis of disease. In the recent years a number of micro imaging modalities have emerged in the field as preferred means for this purpose. They provide 3D volumetric data suitable for analysis, quantification, validation, and visualization of results in animal models. This review highlights the capabilities of microCT, ultrasound and microPET for multimodal imaging of angiogenesis and molecular vascular targets in a mouse model of tumor angiogenesis. The basic principles of the imaging modalities are described and experimental results are presented.
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Affiliation(s)
- Lyubomir Zagorchev
- Angiogenesis Research Center, Dartmouth Medical School, Lebanon, NH
- Clinical Sites Research Program, Philips Research North America, Briarcliff Manor, NY
| | - Mary J. Mulligan-Kehoe
- Angiogenesis Research Center, Dartmouth Medical School, Lebanon, NH
- Department of Surgery, Vascular Section, Dartmouth Medical School, Lebanon, NH
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Lazenby RA, Angus S, Cooper DML, Hallgrímsson B. A three-dimensional microcomputed tomographic study of site-specific variation in trabecular microarchitecture in the human second metacarpal. J Anat 2009; 213:698-705. [PMID: 19094185 DOI: 10.1111/j.1469-7580.2008.00991.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Variation in trabecular microarchitecture is widely accepted as being regulated by both functional (mechanical loading) and genetic parameters, although the relative influence of each is unclear. Studies reporting inter-site differences in trabecular morphology (volume, number and structure) reveal a complex interaction at the gene-environment interface. We report inter- and intra-site variation in trabecular anatomy using a novel model of contralateral (left vs right) and ipsilateral (head vs base) comparisons for the human second metacarpal in a sample of n = 29 historically known 19th century EuroCanadians. Measures of bone volume fraction, structure model index, connectivity, trabecular number, spacing and thickness as well as degree of anisotropy were obtained from 5-mm volumes of interest using three-dimensional microcomputed tomography. We hypothesized that: (i) the more diverse loading environment of metacarpal heads should produce a more robust trabecular architecture than corresponding bases within sides and (ii) the ipsilateral differences between epiphyses will be larger on the right side than on the left side, as a function of handedness. Analysis of covariance (Side x Epiphysis) with Age as covariate revealed a clear dichotomy between labile and constrained architectures within and among anatomical sites. The predicted variation in loading was accommodated by changes in trabecular volume, whereas trabecular structure did not vary significantly by side or by epiphysis within sides. Age was a significant covariate only for females. We conclude that environmental and genetic regulation of bone adaptation may act through distinct pathways and local anatomies to ensure an integrated lattice of sufficient mass to meet normal functional demands.
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Affiliation(s)
- Richard A Lazenby
- Anthropology Program, University of Northern British Columbia, Prince George, BC, Canada.
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Phenotypic integration among trabecular and cortical bone traits establishes mechanical functionality of inbred mouse vertebrae. J Bone Miner Res 2009; 24:606-20. [PMID: 19063678 PMCID: PMC2659510 DOI: 10.1359/jbmr.081224] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Conventional approaches to identifying quantitative trait loci (QTLs) regulating bone mass and fragility are limited because they examine cortical and trabecular traits independently. Prior work examining long bones from young adult mice and humans indicated that skeletal traits are functionally related and that compensatory interactions among morphological and compositional traits are critical for establishing mechanical function. However, it is not known whether trait covariation (i.e., phenotypic integration) also is important for establishing mechanical function in more complex, corticocancellous structures. Covariation among trabecular, cortical, and compositional bone traits was examined in the context of mechanical functionality for L(4) vertebral bodies across a panel of 16-wk-old female AXB/BXA recombinant inbred (RI) mouse strains. The unique pattern of randomization of the A/J and C57BL/6J (B6) genome among the RI panel provides a powerful tool that can be used to measure the tendency for different traits to covary and to study the biology of complex traits. We tested the hypothesis that genetic variants affecting vertebral size and mass are buffered by changes in the relative amounts of cortical and trabecular bone and overall mineralization. Despite inheriting random sets of A/J and B6 genomes, the RI strains inherited nonrandom sets of cortical and trabecular bone traits. Path analysis, which is a multivariate analysis that shows how multiple traits covary simultaneously when confounding variables like body size are taken into consideration, showed that RI strains that tended to have smaller vertebrae relative to body size achieved mechanical functionality by increasing mineralization and the relative amounts of cortical and trabecular bone. The interdependence among corticocancellous traits in the vertebral body indicated that variation in trabecular bone traits among inbred mouse strains, which is often thought to arise from genetic factors, is also determined in part by the adaptive response to variation in traits describing the cortical shell. The covariation among corticocancellous traits has important implications for genetic analyses and for interpreting the response of bone to genetic and environmental perturbations.
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Briggs AM, Straker LM, Wark JD. Bone health and back pain: what do we know and where should we go? Osteoporos Int 2009; 20:209-19. [PMID: 18716821 DOI: 10.1007/s00198-008-0719-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Accepted: 06/18/2008] [Indexed: 02/01/2023]
Abstract
Bone health is generally not considered in patients who present with chronic back pain. Nonetheless, bone health and back pain share common genetic and environmental correlates suggesting a co-dependence. Evidence exists for a relationship between back pain and impaired bone health. Here we present the evidence, theoretic framework and clinical relevance. Bone health and back pain are important determinants of musculoskeletal health. Back pain experienced in youth is a risk factor for future back pain, while suboptimal bone health during development increases the risk of skeletal fragility in later life. Generally, bone health is not considered in patients with chronic back pain who do not demonstrate other well-recognised bone health risk factors or associated conditions. Nonetheless, evidence suggests that back pain and impaired bone health share common environmental and genetic correlates, indicating that bone health ought to be considered in the context of back pain in otherwise healthy individuals. This review describes the likely mechanisms explaining the relationship between back pain and impaired bone health, evidence concerning the relationship and suggestions for future research. A narrative literature search was conducted using CINAHL, Medline, PubMed and Web of Science electronic databases. A history of back pain is associated with decreased bone mineral density in adults, yet this tends to be site-specific. No studies were identified examining this association in youth, yet the negative effects of childhood skeletal trauma and obesity on bone and spinal health provide indirect evidence for an association. Further research is required to clarify the impact of back pain on bone health at different lifespan stages using prospective cohort designs.
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Affiliation(s)
- A M Briggs
- School of Physiotherapy, Curtin University of Technology, Perth, Australia
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Courtland HW, Nasser P, Goldstone AB, Spevak L, Boskey AL, Jepsen KJ. Fourier transform infrared imaging microspectroscopy and tissue-level mechanical testing reveal intraspecies variation in mouse bone mineral and matrix composition. Calcif Tissue Int 2008; 83:342-53. [PMID: 18855037 PMCID: PMC2650490 DOI: 10.1007/s00223-008-9176-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 09/05/2008] [Indexed: 11/24/2022]
Abstract
Fracture susceptibility is heritable and dependent upon bone morphology and quality. However, studies of bone quality are typically overshadowed by emphasis on bone geometry and bone mineral density. Given that differences in mineral and matrix composition exist in a variety of species, we hypothesized that genetic variation in bone quality and tissue-level mechanical properties would also exist within species. Sixteen-week-old female A/J, C57BL/6J (B6), and C3H/HeJ (C3H) inbred mouse femora were analyzed using Fourier transform infrared imaging and tissue-level mechanical testing for variation in mineral composition, mineral maturity, collagen cross-link ratio, and tissue-level mechanical properties. A/J femora had an increased mineral-to-matrix ratio compared to B6. The C3H mineral-to-matrix ratio was intermediate of A/J and B6. C3H femora had reduced acid phosphate and carbonate levels and an increased collagen cross-link ratio compared to A/J and B6. Modulus values paralleled mineral-to-matrix values, with A/J femora being the most stiff, B6 being the least stiff, and C3H having intermediate stiffness. In addition, work-to-failure varied among the strains, with the highly mineralized and brittle A/J femora performing the least amount of work-to-failure. Inbred mice are therefore able to differentially modulate the composition of their bone mineral and the maturity of their bone matrix in conjunction with tissue-level mechanical properties. These results suggest that specific combinations of bone quality and morphological traits are genetically regulated such that mechanically functional bones can be constructed in different ways.
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Affiliation(s)
- Hayden-William Courtland
- Division of Endocrinology, Diabetes, and Bone Diseases, Mount Sinai School of Medicine, New York, NY, USA, e-mail:
| | - Philip Nasser
- Leni & Peter W. May Department of Orthopedics, Mount Sinai School of Medicine, Box 1188, One Gustave Levy Place, New York, NY 10029, USA, e-mail:
| | - Andrew B. Goldstone
- Leni & Peter W. May Department of Orthopedics, Mount Sinai School of Medicine, Box 1188, One Gustave Levy Place, New York, NY 10029, USA, e-mail:
| | - Lyudmila Spevak
- Musculoskeletal Integrity Program, Hospital for Special Surgery, New York, NY, USA, e-mail:
| | - Adele L. Boskey
- Musculoskeletal Integrity Program, Hospital for Special Surgery, New York, NY, USA, e-mail:
| | - Karl J. Jepsen
- Leni & Peter W. May Department of Orthopedics, Mount Sinai School of Medicine, Box 1188, One Gustave Levy Place, New York, NY 10029, USA
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Pleiotropic patterns of quantitative trait loci for 70 murine skeletal traits. Genetics 2008; 178:2275-88. [PMID: 18430949 DOI: 10.1534/genetics.107.084434] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Quantitative trait locus (QTL) studies of a skeletal trait or a few related skeletal components are becoming commonplace, but as yet there has been no investigation of pleiotropic patterns throughout the skeleton. We present a comprehensive survey of pleiotropic patterns affecting mouse skeletal morphology in an intercross of LG/J and SM/J inbred strains (N = 1040), using QTL analysis on 70 skeletal traits. We identify 798 single-trait QTL, coalescing to 105 loci that affect on average 7-8 traits each. The number of traits affected per locus ranges from only 1 trait to 30 traits. Individual traits average 11 QTL each, ranging from 4 to 20. Skeletal traits are affected by many, small-effect loci. Significant additive genotypic values average 0.23 standard deviation (SD) units. Fifty percent of loci show codominance with heterozygotes having intermediate phenotypic values. When dominance does occur, the LG/J allele tends to be dominant to the SM/J allele (30% vs. 8%). Over- and underdominance are relatively rare (12%). Approximately one-fifth of QTL are sex specific, including many for pelvic traits. Evaluating the pleiotropic relationships of skeletal traits is important in understanding the role of genetic variation in the growth and development of the skeleton.
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Identification of quantitative trait loci affecting murine long bone length in a two-generation intercross of LG/J and SM/J Mice. J Bone Miner Res 2008; 23:887-95. [PMID: 18435578 PMCID: PMC2677087 DOI: 10.1359/jbmr.080210] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Study of mutations with large phenotypic effects has allowed the identification of key players in skeletal development. However, the molecular nature of variation in large, phenotypically normal populations tends to be characterized by smaller phenotypic effects that remain undefined. MATERIALS AND METHODS We use interval mapping and quantitative trait locus (QTL) mapping techniques in the combined F2-F3 populations (n = 2111) of an LG/J x SM/J mouse intercross to detect QTLs associated with the lengths of the humerus, ulna, femur, and tibia. RESULTS Seventy individual trait QTLs affecting long bone lengths were detected, with several chromosomes harboring multiple QTLs. The genetic architecture suggests mainly small, additive effects on long bone length, with roughly one third of the QTLs displaying dominance. Sex interactions were common, and four sex-specific QTLs were observed. Pleiotropy could not be rejected for most of the QTLs identified. Thirty-one epistatic interactions were detected, almost all affecting regions including or immediately adjacent to QTLs. CONCLUSIONS A complex regulatory network with many gene interactions modulates bone growth, possibly with integrated skeletal modules that allow fine-tuning of developmental processes present. Candidate genes in the QTL CIs include many genes known to affect endochondral bone growth and genes that have not yet been associated with bone growth or body size but have a strong potential to influence these traits.
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Lazenby RA, Cooper DM, Angus S, Hallgrímsson B. Articular constraint, handedness, and directional asymmetry in the human second metacarpal. J Hum Evol 2008; 54:875-85. [DOI: 10.1016/j.jhevol.2007.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 11/12/2007] [Accepted: 12/06/2007] [Indexed: 10/22/2022]
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Trabecular bone deterioration in col9a1+/- mice associated with enlarged osteoclasts adhered to collagen IX-deficient bone. J Bone Miner Res 2008; 23:837-49. [PMID: 18251701 PMCID: PMC2677084 DOI: 10.1359/jbmr.080214] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Short collagen IX, the exclusive isoform expressed by osteoblasts, is synthesized through alternative transcription of the col9a1 gene. The function of short collagen IX in bone was characterized in col9a1-null mutant mice. MATERIALS AND METHODS Trabecular bone morphometry of lumbar bones and tibias was evaluated by muCT and nondecalcified histology. Osteoblastic and osteoclastic activities were evaluated by PCR- and microarray-based gene expression assays and TRACP-5b and C-terminal telopeptide (CTX) assays, as well as in vitro using bone marrow stromal cells and splenocytes. The effect of col9a1(+/-) mutation on osteoclast morphology was evaluated using RAW264.7-derived osteoclastic cells cultured on the mutant or wildtype calvarial bone substrates. RESULTS Col9a1 knockout mutation caused little effects on the skeletal development; however, young adult female col9a1(-/-) and col9a1(+/-) mice exhibited significant loss of trabecular bone. The trabecular bone architecture was progressively deteriorated in both male and female heterozygous col9a1(+/-) mice while aging. The aged mutant mice also exhibited signs of thoracic kyphosis and weight loss, resembling the clinical signs of osteoporosis. The col9a1(+/-) osteoblasts synthesized short col9a1 transcripts at decreased rates. Whereas bone formation activities in vitro and in vivo were not affected, the mutant osteoblast expressed the elevated ratio of RANKL/osteoprotegerin. Increased serum TRACP-5b and CTX levels were found in col9a1(+/-) mice, whose bone surface was associated with osteoclastic cells that were abnormally flattened and enlarged. The mutant and wildtype splenocytes underwent similar osteoclastogenesis in vitro; however, RAW264.7-derived osteoclastic cells, when cultured on the col9a1(+/-) calvaria, widely spread over the bone surface and formed large resorption pits. The surface of col9a1(+/-) calvaria was found to lack the typical nanotopography. CONCLUSIONS The mineralized bone matrix deficient of short collagen IX may become susceptible to osteoclastic bone resorption, possibly through a novel non-cell-autonomous mechanism. The data suggest the involvement of bone collagen IX in the pathogenesis of osteoporosis.
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Abstract
The risk of osteoporotic fracture can be viewed as a function of loading conditions and the ability of the bone to withstand the load. Skeletal loads are dominated by muscle action. Recently, it has become clear that bone and muscle share genetic determinants. Involution of the musculoskeletal system manifests as bone loss (osteoporosis) and muscle wasting (sarcopenia). Therefore, the consideration of pleiotropy is an important aspect in the study of the genetics of osteoporosis and sarcopenia. This Perspective will provide the evidence for a shared genetic influence on bone and muscle. We will start with an overview of accumulating evidence that physical exercise produces effects on the adult skeleton, seeking to unravel some of the contradictory findings published thus far. We will provide indications that there are pleiotropic relationships between bone structure/mass and muscle mass/function. Finally, we will offer some insights and practical recommendations as to the value of studying shared genetic factors and will explore possible directions for future research. We consider several related questions that together comprise the general paradigm of bone responses to mechanical loading and the relationship between muscle strength and bone parameters, including the genetic factors that modulate these responses. We believe that further progress in understanding the common genetic etiology of osteoporosis and sarcopenia will provide valuable insight into important biological underpinnings for both conditions and may translate into new approaches to reduce the burdens of both conditions through improved diagnosis, prevention, and early targeted treatment.
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Abstract
Common diseases result from the complex relationship between genetic and environmental factors. The aim of this review is to provide perspective for a conceptual framework aimed at studying the interplay of gender-specific genetic and environmental factors in the etiology of complex disease, using osteoporosis as an example. In recent years, gender differences in the heritability of the osteoporosis-related phenotypes have been reported and sex-specific quantitative-trait loci were discovered by linkage studies in humans and mice. Results of numerous allelic association studies also differed by gender. In most cases, it was not clear whether or not this phenomenon should be attributed to the effect of sex-chromosomes, sex hormones, or other intrinsic or extrinsic differences between the genders, such as the level of bioavailable estrogen and of physical activity. We conclude that there is need to consider gender-specific genetic and environmental factors in the planning of future association studies on the etiology of osteoporosis and other complex diseases prevalent in the general population.
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Affiliation(s)
- D Karasik
- Hebrew SeniorLife/IFAR and Harvard Medical School, Boston, MA 02131, USA.
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Sode M, Burghardt AJ, Nissenson RA, Majumdar S. Resolution dependence of the non-metric trabecular structure indices. Bone 2008; 42:728-36. [PMID: 18276202 PMCID: PMC2329672 DOI: 10.1016/j.bone.2007.12.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2007] [Revised: 11/18/2007] [Accepted: 12/10/2007] [Indexed: 11/16/2022]
Abstract
Non-metric indices of topological features of trabecular bone structure, such as structure model index (SMI), connectivity density (Conn.D), and degree of anisotropy (DA), provide unique information relevant to bone quality. With recent technological advancement, in vivo assessment of these indices may be possible from images acquired using high-resolution imaging techniques such as high-resolution peripheral quantitative computed tomography (HR-pQCT). However, more detailed investigation of the dependence of non-metric indices on spatial resolution is needed to determine their applicability. The purpose of this study was to determine whether these three non-metric indices are affected by the spatial resolution of CT images. First, the SMI, Conn.D, and DA were calculated for trabecular bone specimens with varying plate-like and rod-like structures from resampled muCT images across a range of spatial resolutions and compared to the reference values. To account for differences in size across different species and anatomical sites, the results are reported in normalized resolution units. Next, the impact of resolution on the non-metric indices for cores of human distal tibia trabecular bone from clinical HR-pQCT images was evaluated to determine the applicability of the non-metric indices to in vivo imaging. We found that the non-metric indices of trabecular bone structure were affected by spatial resolution of CT images. Particularly, the SMI deviated from the high-resolution muCT reference value depending on the structure type, whether plate-like or rod-like. Both Conn.D and DA were underestimated in the images obtained at an in vivo resolution. It is not trivial to determine absolute threshold for validity of these non-metric indices without considering a specific study design (e.g. relative resolution, the size of the treatment effect to detect, and specimen type). The results of this study provide an upper bound for the accuracy of the non-metric indices under limited resolution scenarios.
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Affiliation(s)
- Miki Sode
- Joint Graduate Group in Bioengineering, University of California at San Francisco and Berkeley, San Francisco and Berkeley, CA, USA.
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