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Xing W, Pourteymoor S, Udayakumar A, Chen Y, Mohan S. Targeted Overexpression of Claudin 11 in Osteoblasts Increases Trabecular Bone Mass by Stimulating Osteogenesis at the Expense of Adipogenesis in Mice. BIOLOGY 2024; 13:108. [PMID: 38392326 PMCID: PMC10886834 DOI: 10.3390/biology13020108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024]
Abstract
Mice lacking Claudin11 (Cldn11) manifest reduced trabecular bone mass. However, the impact of Cldn11 expression in osteoblasts in vivo remains understudied. Herein, we generated osteoblast-specific transgenic (Tg) mice expressing Cldn11 and characterized their skeletal phenotype. Micro-CT analyses of the distal metaphysis of the femur showed a 50% and a 38% increase in trabecular bone mass in Tg male and female mice, respectively, due to a significant increase in trabecular number and a reduction in trabecular separation. Histomorphometry and serum biomarker studies uncovered that increased trabecular bone mass in Cldn11 Tg mice was the consequence of enhanced bone formation. Accordingly, an abundance of bone formation (Alp, Bsp), but not bone resorption (Ctsk), markers were augmented in the femurs of Cldn11 Tg mice. Since the trabecular bone density is known to inversely correlate with the amount of marrow adipose tissue (MAT), we measured the MAT in osmium-tetroxide-labeled bones by micro-CT scanning. We found 86% less MAT in the proximal tibia of the Tg males. Consistently, the expression levels of the adipogenic markers, adiponectin and leptin, were 50% lower in the femurs of the Tg males. Our data are consistent with the possibility that claudin11 exerts anabolic effects in osteoblastic lineage cells that act via promoting the differentiation of marrow stem cells towards osteoblasts at the expense of adipocytes.
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Affiliation(s)
- Weirong Xing
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Sheila Pourteymoor
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA
| | - Anakha Udayakumar
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA
- Graduate School, Loma Linda University, Loma Linda, CA 92354, USA
| | - Yian Chen
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
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2
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Zhang YY, Li F, Zeng XK, Zou YH, Zhu BB, Ye JJ, Zhang YX, Jin Q, Nie X. Single cell RNA sequencing reveals mesenchymal heterogeneity and critical functions of Cd271 in tooth development. World J Stem Cells 2023; 15:589-606. [PMID: 37424952 PMCID: PMC10324503 DOI: 10.4252/wjsc.v15.i6.589] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/18/2023] [Accepted: 05/05/2023] [Indexed: 06/20/2023] Open
Abstract
BACKGROUND Accumulating evidence suggests that the maxillary process, to which cranial crest cells migrate, is essential to tooth development. Emerging studies indicate that Cd271 plays an essential role in odontogenesis. However, the underlying mechanisms have yet to be elucidated.
AIM To establish the functionally heterogeneous population in the maxillary process, elucidate the effects of Cd271 deficiency on gene expression differences.
METHODS p75NTR knockout (Cd271-/-) mice (from American Jackson laboratory) were used to collect the maxillofacial process tissue of p75NTR knockout mice, and the wild-type maxillofacial process of the same pregnant mouse wild was used as control. After single cell suspension, the cDNA was prepared by loading the single cell suspension into the 10x Genomics Chromium system to be sequenced by NovaSeq6000 sequencing system. Finally, the sequencing data in Fastq format were obtained. The FastQC software is used to evaluate the quality of data and CellRanger analyzed the data. The gene expression matrix is read by R software, and Seurat is used to control and standardize the data, reduce the dimension and cluster. We search for marker genes for subgroup annotation by consulting literature and database; explore the effect of p75NTR knockout on mesenchymal stem cells (MSCs) gene expression and cell proportion by cell subgrouping, differential gene analysis, enrichment analysis and protein-protein interaction network analysis; understand the interaction between MSCs cells and the differentiation trajectory and gene change characteristics of p75NTR knockout MSCs by cell communication analysis and pseudo-time analysis. Last we verified the findings single cell sequencing in vitro.
RESULTS We identified 21 cell clusters, and we re-clustered these into three subclusters. Importantly, we revealed the cell–cell communication networks between clusters. We clarified that Cd271 was significantly associated with the regulation of mineralization.
CONCLUSION This study provides comprehensive mechanistic insights into the maxillary- process-derived MSCs and demonstrates that Cd271 is significantly associated with the odontogenesis in mesenchymal populations.
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Affiliation(s)
- Yan-Yan Zhang
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Feng Li
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Xiao-Ke Zeng
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Yan-Hui Zou
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Bing-Bing Zhu
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Jia-Jia Ye
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Yun-Xiao Zhang
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Qiu Jin
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Xin Nie
- School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
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3
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Abstract
Although osteoblasts and osteocytes are descended from the same lineage, they each have unique and essential roles in bone. Targeting gene deletion to osteoblasts and osteocytes using the Cre/loxP system has greatly increased our current understanding of how these cells function. Additionally, the use of the Cre/loxP system in conjunction with cell-specific reporters has enabled lineage tracing of these bone cells both in vivo and ex vivo. However, concerns have been raised regarding the specificity of the promoters used and the resulting off-target effects on cells within and outside of the bone. In this review, we have summarized the main mouse models that have been used to determine the functions of specific genes in osteoblasts and osteocytes. We discuss the expression patterns and specificity of the different promoter fragments during osteoblast to osteocyte differentiation in vivo. We also highlight how their expression in non-skeletal tissues may complicate the interpretation of study results. A thorough understanding of when and where these promoters are activated will enable improved study design and greater confidence in data interpretation.
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Affiliation(s)
- Y Kitase
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States of America
| | - M Prideaux
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States of America.
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4
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Weivoda MM, Bradley EW. Macrophages and Bone Remodeling. J Bone Miner Res 2023; 38:359-369. [PMID: 36651575 PMCID: PMC10023335 DOI: 10.1002/jbmr.4773] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 01/19/2023]
Abstract
Bone remodeling in the adult skeleton facilitates the removal and replacement of damaged and old bone to maintain bone quality. Tight coordination of bone resorption and bone formation during remodeling crucially maintains skeletal mass. Increasing evidence suggests that many cell types beyond osteoclasts and osteoblasts support bone remodeling, including macrophages and other myeloid lineage cells. Herein, we discuss the origin and functions for macrophages in the bone microenvironment, tissue resident macrophages, osteomacs, as well as newly identified osteomorphs that result from osteoclast fission. We also touch on the role of macrophages during inflammatory bone resorption. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
| | - Elizabeth W. Bradley
- Department of Orthopedics and Stem Cell Institute, University of Minnesota, Minneapolis, MN
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5
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Hixon KR, McKenzie JA, Sykes DAW, Yoneda S, Hensley A, Buettmann EG, Zheng H, Skouteris D, McAlinden A, Miller AN, Silva MJ. Ablation of Proliferating Osteoblast Lineage Cells After Fracture Leads to Atrophic Nonunion in a Mouse Model. J Bone Miner Res 2021; 36:2243-2257. [PMID: 34405443 PMCID: PMC8719642 DOI: 10.1002/jbmr.4424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 07/15/2021] [Accepted: 08/10/2021] [Indexed: 01/19/2023]
Abstract
Nonunion is defined as the permanent failure of a fractured bone to heal, often necessitating surgical intervention. Atrophic nonunions are a subtype that are particularly difficult to treat. Animal models of atrophic nonunion are available; however, these require surgical or radiation-induced trauma to disrupt periosteal healing. These methods are invasive and not representative of many clinical nonunions where osseous regeneration has been arrested by a "failure of biology". We hypothesized that arresting osteoblast cell proliferation after fracture would lead to atrophic nonunion in mice. Using mice that express a thymidine kinase (tk) "suicide gene" driven by the 3.6Col1a1 promoter (Col1-tk), proliferating osteoblast lineage cells can be ablated upon exposure to the nucleoside analog ganciclovir (GCV). Wild-type (WT; control) and Col1-tk littermates were subjected to a full femur fracture and intramedullary fixation at 12 weeks age. We confirmed abundant tk+ cells in fracture callus of Col-tk mice dosed with water or GCV, specifically many osteoblasts, osteocytes, and chondrocytes at the cartilage-bone interface. Histologically, we observed altered callus composition in Col1-tk mice at 2 and 3 weeks postfracture, with significantly less bone and more fibrous tissue. Col1-tk mice, monitored for 12 weeks with in vivo radiographs and micro-computed tomography (μCT) scans, had delayed bone bridging and reduced callus size. After euthanasia, ex vivo μCT and histology showed failed union with residual bone fragments and fibrous tissue in Col1-tk mice. Biomechanical testing showed a failure to recover torsional strength in Col1-tk mice, in contrast to WT. Our data indicates that suppression of proliferating osteoblast-lineage cells for at least 2 weeks after fracture blunts the formation and remodeling of a mineralized callus leading to a functional nonunion. We propose this as a new murine model of atrophic nonunion. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Katherine R Hixon
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Jennifer A McKenzie
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - David A W Sykes
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | - Susumu Yoneda
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Austin Hensley
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Evan G Buettmann
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Hongjun Zheng
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Dimitrios Skouteris
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Audrey McAlinden
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA.,Department of Cell Biology & Physiology, Washington University in St. Louis, St. Louis, MO, USA.,St. Louis Shriners Hospital Research Center, Shriners Hospital for Children, St. Louis, MO, USA
| | - Anna N Miller
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Matthew J Silva
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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6
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Nottmeier C, Liao N, Simon A, Decker MG, Luther J, Schweizer M, Yorgan T, Kaucka M, Bockamp E, Kahl-Nieke B, Amling M, Schinke T, Petersen J, Koehne T. Wnt1 Promotes Cementum and Alveolar Bone Growth in a Time-Dependent Manner. J Dent Res 2021; 100:1501-1509. [PMID: 34009051 PMCID: PMC8649456 DOI: 10.1177/00220345211012386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The WNT/β-catenin signaling pathway plays a central role in the biology
of the periodontium, yet the function of specific extracellular WNT
ligands remains poorly understood. By using a
Wnt1-inducible transgenic mouse model targeting
Col1a1-expressing alveolar osteoblasts,
odontoblasts, and cementoblasts, we demonstrate that the WNT ligand
WNT1 is a strong promoter of cementum and alveolar bone formation in
vivo. We induced Wnt1 expression for 1, 3, or 9 wk in
Wnt1Tg mice and analyzed them at the age of 6 wk and 12 wk.
Micro–computed tomography (CT) analyses of the mandibles revealed a
1.8-fold increased bone volume after 1 and 3 wk of
Wnt1 expression and a 3-fold increased bone
volume after 9 wk of Wnt1 expression compared to
controls. In addition, the alveolar ridges were higher in Wnt1Tg mice
as compared to controls. Nondecalcified histology demonstrated
increased acellular cementum thickness and cellular cementum volume
after 3 and 9 wk of Wnt1 expression. However, 9 wk of
Wnt1 expression was also associated with
periodontal breakdown and ectopic mineralization of the pulp. The
composition of this ectopic matrix was comparable to those of cellular
cementum as demonstrated by quantitative backscattered electron
imaging and immunohistochemistry for noncollagenous proteins. Our
analyses of 52-wk-old mice after 9 wk of Wnt1
expression revealed that Wnt1 expression affects
mandibular bone and growing incisors but not molar teeth, indicating
that Wnt1 influences only growing tissues. To further
investigate the effect of Wnt1 on cementoblasts, we
stably transfected the cementoblast cell line (OCCM-30) with a vector
expressing Wnt1-HA and performed proliferation as
well as differentiation experiments. These experiments demonstrated
that Wnt1 promotes proliferation but not
differentiation of cementoblasts. Taken together, our findings
identify, for the first time, Wnt1 as a critical
regulator of alveolar bone and cementum formation, as well as provide
important insights for harnessing the WNT signal pathway in
regenerative dentistry.
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Affiliation(s)
- C Nottmeier
- Department of Orthodontics, University Medical Center Hamburg, Hamburg, Germany.,Department of Orthodontics, University of Leipzig Medical Center, Leipzig, Germany
| | - N Liao
- Department of Orthodontics, University Medical Center Hamburg, Hamburg, Germany.,Department of Orthodontics, College of Stomatology, North China University of Science and Technology, Tangshan, China
| | - A Simon
- Department of Orthodontics, University Medical Center Hamburg, Hamburg, Germany
| | - M G Decker
- Department of Orthodontics, University Medical Center Hamburg, Hamburg, Germany
| | - J Luther
- Department of Osteology and Biomechanics, University Medical Center Hamburg, Hamburg, Germany
| | - M Schweizer
- ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - T Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg, Hamburg, Germany
| | - M Kaucka
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - E Bockamp
- Institute for Translational Immunology and Research Center for Immunotherapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - B Kahl-Nieke
- Department of Orthodontics, University Medical Center Hamburg, Hamburg, Germany
| | - M Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg, Hamburg, Germany
| | - T Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg, Hamburg, Germany
| | - J Petersen
- Department of Orthodontics, University of Leipzig Medical Center, Leipzig, Germany.,Department of Osteology and Biomechanics, University Medical Center Hamburg, Hamburg, Germany
| | - T Koehne
- Department of Orthodontics, University Medical Center Hamburg, Hamburg, Germany.,Department of Orthodontics, University of Leipzig Medical Center, Leipzig, Germany
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7
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Abstract
The circulatory system carries within it numerous types of cells, proteins, and other factors that are able to influence the local biology of tissues. Within this chapter, we present a protocol for parabiosis, a surgical model which results in shared circulation between two mice. Such chimeras have recently been used to probe the impact of age-associated changes in the circulation on skeletal, muscular, and neural biology. In conjunction with transgenic mouse models, parabiosis can be used as a tool to investigate the effects of specific factors on local tissues. Here we discuss our adaptation of this surgical procedure including technique details, pitfalls, and suggestions for optimization.
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8
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Freiin von Hövel F, Kefalakes E, Grothe C. What Can We Learn from FGF-2 Isoform-Specific Mouse Mutants? Differential Insights into FGF-2 Physiology In Vivo. Int J Mol Sci 2020; 22:ijms22010390. [PMID: 33396566 PMCID: PMC7795026 DOI: 10.3390/ijms22010390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/29/2020] [Accepted: 12/29/2020] [Indexed: 12/16/2022] Open
Abstract
Fibroblast growth factor 2 (FGF-2), ubiquitously expressed in humans and mice, is functionally involved in cell growth, migration and maturation in vitro and in vivo. Based on the same mRNA, an 18-kilo Dalton (kDa) FGF-2 isoform named FGF-2 low molecular weight (FGF-2LMW) isoform is translated in humans and rodents. Additionally, two larger isoforms weighing 21 and 22 kDa also exist, summarized as the FGF-2 high molecular weight (FGF-2HMW) isoform. Meanwhile, the human FGF-2HMW comprises a 22, 23, 24 and 34 kDa protein. Independent studies verified a specific intracellular localization, mode of action and tissue-specific spatiotemporal expression of the FGF-2 isoforms, increasing the complexity of their physiological and pathophysiological roles. In order to analyze their spectrum of effects, FGF-2LMW knock out (ko) and FGF-2HMWko mice have been generated, as well as mice specifically overexpressing either FGF-2LMW or FGF-2HMW. So far, the development and functionality of the cardiovascular system, bone formation and regeneration as well as their impact on the central nervous system including disease models of neurodegeneration, have been examined. This review provides a summary of the studies characterizing the in vivo effects modulated by the FGF-2 isoforms and, thus, offers a comprehensive overview of its actions in the aforementioned organ systems.
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Affiliation(s)
- Friederike Freiin von Hövel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Carl-Neuberg-Straße 1, D-30625 Hannover, Germany;
- Center for Systems Neuroscience (ZSN), University of Veterinary Medicine, Bünteweg 2, D-30559 Hannover, Germany;
| | - Ekaterini Kefalakes
- Center for Systems Neuroscience (ZSN), University of Veterinary Medicine, Bünteweg 2, D-30559 Hannover, Germany;
| | - Claudia Grothe
- Center for Systems Neuroscience (ZSN), University of Veterinary Medicine, Bünteweg 2, D-30559 Hannover, Germany;
- Correspondence: ; Tel.: +49-511-532-2897; Fax: +49-511-532-2880
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9
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Deciphering the potential pharmaceutical mechanism of Guzhi Zengsheng Zhitongwan on rat bone and kidney based on the "kidney governing bone" theory. J Orthop Surg Res 2020; 15:146. [PMID: 32295616 PMCID: PMC7161198 DOI: 10.1186/s13018-020-01677-8] [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: 12/16/2019] [Accepted: 04/08/2020] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Guzhi Zengsheng Zhitongwan (GZZSZTW) is an effective Chinese medicinal formulation for the treatment of osteoarthritis (OA) designed according to the "kidney governing bone" theory, which has been widely used as a golden guide for treating bone and cartilage diseases in traditional Chinese medicine. The aim of this study was to explore the molecular mechanism underlying its effects on the bone and kidney. METHODS Preparation and quality control were performed as previously described. Since GZZSZTW is orally administered in the form of pills prepared in boiled water, the Chinese materia medica (CMM) mixture of this formula was extracted with distilled water by a reflux method and was then filtered through a 0.45-μm Hollow Fiber Cartridge (GE Healthcare, USA). The filtrate was freeze-dried by a Heto PowerDry LL3000 Freeze Dryer (Thermo, USA) and stored at - 80 °C. The effects of GZZSZTW on gene expression and regulation of both kidney and bone tissues were investigated using a state-of-the-art RNA-seq technology. RESULTS We demonstrated that GZZSZTW could enhance kidney function and suppress bone formation and resorption by modulating the activities of osteoblast and osteoclast, and might subsequently contribute to the inhibition of osteophyte formation during the process of OA. These effects might be achieved by the synergistic interactions of various herbs and their active components in GZZSZTW, which increased the expression levels of functional genes participating in kidney function, regulation, and repair, and then decreased the expression levels of genes involved in bone formation and resorption. Thus, our findings were consistent with the "kidney governing bone" theory, which has been widely used as a guide in clinical practice for thousands of years. CONCLUSIONS This study has deepened the current knowledge about the molecular effects of GZZSZTW on bone and kidney regulation. Furthermore, this study might be able to provide possible strategies to further prevent and treat joint diseases by using traditional Chinese medicinal formulations following the "kidney governing bone" theory.
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10
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Novak S, Roeder E, Kalinowski J, Jastrzebski S, Aguila HL, Lee SK, Kalajzic I, Lorenzo JA. Osteoclasts Derive Predominantly from Bone Marrow-Resident CX 3CR1 + Precursor Cells in Homeostasis, whereas Circulating CX 3CR1 + Cells Contribute to Osteoclast Development during Fracture Repair. THE JOURNAL OF IMMUNOLOGY 2020; 204:868-878. [PMID: 31915261 DOI: 10.4049/jimmunol.1900665] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 12/12/2019] [Indexed: 01/10/2023]
Abstract
Osteoclasts (OC) originate from either bone marrow (BM)-resident or circulating myeloid OC progenitors (OCP) expressing the receptor CX3CR1. Multiple lines of evidence argue that OCP in homeostasis and inflammation differ. We investigated the relative contributions of BM-resident and circulating OCP to osteoclastogenesis during homeostasis and fracture repair. Using CX3CR1-EGFP/TRAP tdTomato mice, we found CX3CR1 expression in mononuclear cells, but not in multinucleated TRAP+ OC. However, CX3CR1-expressing cells generated TRAP+ OC on bone within 5 d in CX3CR1CreERT2/Ai14 tdTomato reporter mice. To define the role that circulating cells play in osteoclastogenesis during homeostasis, we parabiosed TRAP tdTomato mice (CD45.2) on a C57BL/6 background with wild-type (WT) mice (CD45.1). Flow cytometry (CD45.1/45.2) demonstrated abundant blood cell mixing between parabionts after 2 wk. At 4 wk, there were numerous tdTomato+ OC in the femurs of TRAP tdTomato mice but almost none in WT mice. Similarly, cultured BM stimulated to form OC demonstrated multiple fluorescent OC in cell cultures from TRAP tdTomato mice, but not from WT mice. Finally, flow cytometry confirmed low-level engraftment of BM cells between parabionts but significant engraftment in the spleens. In contrast, during fracture repair, we found that circulating CX3CR1+ cells migrated to bone, lost expression of CX3CR1, and became OC. These data demonstrate that OCP, but not mature OC, express CX3CR1 during both homeostasis and fracture repair. We conclude that, in homeostasis mature OC derive predominantly from BM-resident OCP, whereas during fracture repair, circulating CX3CR1+ cells can become OC.
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Affiliation(s)
- Sanja Novak
- Department of Reconstructive Sciences, UConn Health, Farmington, CT 06030
| | - Emilie Roeder
- Department of Reconstructive Sciences, UConn Health, Farmington, CT 06030
| | | | | | - Hector L Aguila
- Department of Immunology, UConn Health, Farmington, CT 06030
| | - Sun-Kyeong Lee
- University of Connecticut Center on Aging, UConn Health, Farmington, CT 06030; and
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, UConn Health, Farmington, CT 06030
| | - Joseph A Lorenzo
- Department of Medicine, UConn Health, Farmington, CT 06030; .,Department of Orthopaedic Surgery, UConn Health, Farmington, CT 06030
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11
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Sinder BP, Novak S, Wee NKY, Basile M, Maye P, Matthews BG, Kalajzic I. Engraftment of skeletal progenitor cells by bone-directed transplantation improves osteogenesis imperfecta murine bone phenotype. Stem Cells 2019; 38:530-541. [PMID: 31859429 DOI: 10.1002/stem.3133] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/22/2019] [Indexed: 12/12/2022]
Abstract
Osteogenesis imperfecta (OI) is a genetic disorder most commonly caused by mutations associated with type I collagen, resulting in a defective collagen bone matrix. Current treatments for OI focus on pharmaceutical strategies to increase the amount of defective bone matrix, but do not address the underlying collagen defect. Introducing healthy donor stem cells that differentiate into osteoblasts producing normal collagen in OI patients has the potential to increase bone mass and correct the mutant collagen matrix. In this study, donor bone marrow stromal cells (BMSCs, also known as bone marrow mesenchymal stem cells) expressing both αSMACreERT2/Ai9 progenitor reporter and osteoblast reporter Col2.3GFP were locally transplanted into the femur of OI murine (OIM) mice. One month post-transplantation, 18% of the endosteal surface was lined by donor Col2.3GFP expressing osteoblasts indicating robust engraftment. Long-term engraftment in the marrow was observed 3 and 6 months post-transplantation. The presence of Col1a2-expressing donor cell-derived cortical bone matrix was detected in transplanted OIM femurs. Local transplantation of BMSCs increased cortical thickness (+12%), the polar moment of inertia (+14%), bone strength (+30%), and stiffness (+30%) 3 months post-transplantation. Engrafted cells expressed progenitor markers CD51 and Sca-1 up to 3 months post-transplantation. Most importantly, 3 months post-transplantation donor cells maintained the ability to differentiate into Col2.3GFP+ osteoblasts in vitro, and in vivo following secondary transplantation into OIM animals. Locally transplanted BMSCs can improve cortical structure and strength, and persist as continued source of osteoblast progenitors in the OIM mouse for at least 6 months.
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Affiliation(s)
- Benjamin P Sinder
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut
| | - Sanja Novak
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut
| | - Natalie K Y Wee
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut
| | - Mariangela Basile
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut
| | - Peter Maye
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut
| | - Brya G Matthews
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut.,Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut
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12
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Borriello A, Caldarelli I, Bencivenga D, Stampone E, Perrotta S, Oliva A, Della Ragione F. Tyrosine kinase inhibitors and mesenchymal stromal cells: effects on self-renewal, commitment and functions. Oncotarget 2018; 8:5540-5565. [PMID: 27750212 PMCID: PMC5354929 DOI: 10.18632/oncotarget.12649] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/04/2016] [Indexed: 12/18/2022] Open
Abstract
The hope of selectively targeting cancer cells by therapy and eradicating definitively malignancies is based on the identification of pathways or metabolisms that clearly distinguish “normal” from “transformed” phenotypes. Some tyrosine kinase activities, specifically unregulated and potently activated in malignant cells, might represent important targets of therapy. Consequently, tyrosine kinase inhibitors (TKIs) might be thought as the “vanguard” of molecularly targeted therapy for human neoplasias. Imatinib and the successive generations of inhibitors of Bcr-Abl1 kinase, represent the major successful examples of TKI use in cancer treatment. Other tyrosine kinases have been selected as targets of therapy, but the efficacy of their inhibition, although evident, is less definite. Two major negative effects exist in this therapeutic strategy and are linked to the specificity of the drugs and to the role of the targeted kinase in non-malignant cells. In this review, we will discuss the data available on the TKIs effects on the metabolism and functions of mesenchymal stromal cells (MSCs). MSCs are widely distributed in human tissues and play key physiological roles; nevertheless, they might be responsible for important pathologies. At present, bone marrow (BM) MSCs have been studied in greater detail, for both embryological origins and functions. The available data are evocative of an unexpected degree of complexity and heterogeneity of BM-MSCs. It is conceivable that this grade of intricacy occurs also in MSCs of other organs. Therefore, in perspective, the negative effects of TKIs on MSCs might represent a critical problem in long-term cancer therapies based on such inhibitors.
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Affiliation(s)
- Adriana Borriello
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Ilaria Caldarelli
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Debora Bencivenga
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Emanuela Stampone
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Silverio Perrotta
- Department of Woman, Child and of General and Specialized Surgery, Second University of Naples, Naples, Italy
| | - Adriana Oliva
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Fulvio Della Ragione
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
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13
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Roeder E, Matthews BG, Kalajzic I. Visual reporters for study of the osteoblast lineage. Bone 2016; 92:189-195. [PMID: 27616604 PMCID: PMC5056847 DOI: 10.1016/j.bone.2016.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 12/24/2022]
Abstract
Advancing our understanding of osteoblast biology and differentiation is critical to elucidate the pathological mechanisms responsible for skeletal diseases such as osteoporosis. Histology and histomorphometry, the classical methods to study osteoblast biology, identify osteoblasts based on their location and morphology and ability to mineralize matrix, but do not clearly define their stage of differentiation. Introduction of visual transgenes into the cells of osteoblast lineage has revolutionized the field and resulted in a paradigm shift that allowed for specific identification and isolation of subpopulations within the osteoblast lineage. Knowledge acquired from the studies based on GFP transgenes has allowed for more precise interpretation of studies analyzing targeted overexpression or deletion of genes in the osteoblast lineage. Here, we provide a condensed overview of the currently available promoter-fluorescent reporter transgenic mice that have been generated and evaluated to varying extents. We cover different stages of the lineage as transgenes have been utilized to identify osteoprogenitors, pre-osteoblasts, osteoblasts, or osteocytes. We show that each of these promoters present with advantages and disadvantages. The studies based on the use of these reporter mice have improved our understanding of bone biology. They constitute attractive models to target osteoblasts and help to understand their cell biology.
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Affiliation(s)
- Emilie Roeder
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Brya G Matthews
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA; Department of Pathophysiology, University of Osijek, Osijek, Croatia.
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Abstract
Notch controls skeletogenesis, but its role in the remodeling of adult bone remains conflicting. In mature mice, the skeleton can become osteopenic or osteosclerotic depending on the time point at which Notch is activated or inactivated. Using adult EGFP reporter mice, we find that Notch expression is localized to osteocytes embedded within bone matrix. Conditional activation of Notch signaling in osteocytes triggers profound bone formation, mainly due to increased mineralization, which rescues both age-associated and ovariectomy-induced bone loss and promotes bone healing following osteotomy. In parallel, mice rendered haploinsufficient in γ-secretase presenilin-1 (Psen1), which inhibits downstream Notch activation, display almost-absent terminal osteoblast differentiation. Consistent with this finding, pharmacologic or genetic disruption of Notch or its ligand Jagged1 inhibits mineralization. We suggest that stimulation of Notch signaling in osteocytes initiates a profound, therapeutically relevant, anabolic response.
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15
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Yu J, Cao J, Li H, Liu P, Xu S, Zhou R, Yao Z, Guo X. Bone marrow fibrosis with fibrocytic and immunoregulatory responses induced by β-catenin activation in osteoprogenitors. Bone 2016; 84:38-46. [PMID: 26688275 DOI: 10.1016/j.bone.2015.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/14/2015] [Accepted: 12/09/2015] [Indexed: 12/17/2022]
Abstract
Wnt/β-catenin signaling has been reported to contribute to the development of bone fibrous dysplasia. However, it remains unclear whether fibrocytes and immune cells are involved in this β-catenin-mediated bone marrow fibrosis. In this study, we showed that constitutive activation of β-catenin by Col1a1-Cre (3.6-kb) exhibited bone marrow fibrosis, featured with expanded populations of fibrocytes, myofibroblasts and osteoprogenitors. Lineage tracing and IHC examinations showed that Col3.6-Cre display Cre recombinase activity not only in osteoprogenitors, but also in monocyte-derived fibrocytes in the endosteal niches of bones. Additionally, β-catenin stimulated the secretion of cytokines and pro-fibrotic signals in bone marrow, including GM-CSF, TGFβ1 and VEGF. Consequently, the frequency of differentiated immature monocyte-derived dendritic cells and naïve T cells was markedly increased in the mutant bone marrow. These phenotypes were quite different from those following β-catenin activation in mature osteoblasts driven by Col1a1-Cre (2.3-kb). Our findings suggested that a conserved pro-fibrotic signal cascade might underlie β-catenin-mediated bone marrow fibrosis, involving TGFβ1-enhanced fibrocyte activation and immunoregulatory responses. This study might shed new light on the understanding and development of a therapeutic strategy for bone fibrous dysplasia.
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Affiliation(s)
- Jian Yu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingjing Cao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hanjun Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pei Liu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shuqin Xu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rujiang Zhou
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhengju Yao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Xizhi Guo
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China.
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16
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Gohil SV, Kuo C, Adams DJ, Maye P, Rowe DW, Nair LS. Evaluation of the donor cell contribution in rh
BMP
‐2 mediated bone formation with chitosan thermogels using fluorescent protein reporter mice. J Biomed Mater Res A 2016; 104:928-41. [DOI: 10.1002/jbm.a.35634] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/18/2015] [Accepted: 12/18/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Shalini V. Gohil
- Department of Orthopaedic SurgeryUConn HealthFarmington Connecticut06030
- Institute for Regenerative Engineering, The Raymond Beverly Sackler Center for Biomedical, Biological, Physical and Engineering SciencesUConn HealthFarmington Connecticut06030
| | - Chia‐Ling Kuo
- Connecticut Institute for Clinical and Translational Science, Institute for Systems Genomics, University of ConnecticutFarmington Connecticut06030
| | - Douglas J. Adams
- Department of Orthopaedic SurgeryUConn HealthFarmington Connecticut06030
| | - Peter Maye
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental MedicineUConn HealthFarmington Connecticut06030
| | - David W. Rowe
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental MedicineUConn HealthFarmington Connecticut06030
| | - Lakshmi S. Nair
- Department of Orthopaedic SurgeryUConn HealthFarmington Connecticut06030
- Institute for Regenerative Engineering, The Raymond Beverly Sackler Center for Biomedical, Biological, Physical and Engineering SciencesUConn HealthFarmington Connecticut06030
- Departments of Material Science and Engineering, Biomedical Engineering and Institute of Material ScienceUniversity of ConnecticutStorrs Connecticut06269
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17
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Gohil SV, Brittain SB, Kan HM, Drissi H, Rowe DW, Nair LS. Evaluation of enzymatically crosslinked injectable glycol chitosan hydrogel. J Mater Chem B 2015; 3:5511-5522. [PMID: 32262522 DOI: 10.1039/c5tb00663e] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Enzymatically cross-linkable phenol-conjugated glycol chitosan was prepared by reacting glycol chitosan with 3-(4-hydroxyphenyl)propionic acid (HPP). The chemical modification was confirmed by FTIR, 1H-NMR and UV spectroscopy. Glycol chitosan hydrogels (HPP-GC) with or without rhBMP-2 were prepared by the oxidative coupling of the substituted phenol groups in the presence of hydrogen peroxide and horse radish peroxidase. Rheological characterization demonstrated the feasibility of developing hydrogels with varying storage moduli by changing the polymer concentration. The gel presented a microporous structure with pore sizes ranging from 50-350 μm. The good viability of encapsulated 7F2 osteoblasts indicated non-toxicity of the gelation conditions. In vitro release of rhBMP-2 in phosphate buffer solution showed ∼11% release in 360 h. The ability of the hydrogel to maintain the in vivo bioactivity of rhBMP-2 was evaluated in a bilateral critical size calvarial bone defect model in Col3.6 transgenic fluorescent reporter mice. The presence of fluorescent green osteoblast cells with overlying red alizarin complexone and yellow stain indicating osteoclast TRAP activity confirmed active cell-mediated mineralization and remodelling process at the implantation site. The complete closure of the defect site at 4 and 8 weeks post implantation demonstrated the potent osteoinductivity of the rhBMP-2 containing gel.
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Affiliation(s)
- Shalini V Gohil
- Department of Orthopaedic Surgery, UConn Health, E-7041, MC-3711, 263 Farmington Avenue, Farmington, Connecticut 06030, USA.
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18
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Zanotti S, Canalis E. Activation of Nfatc2 in osteoblasts causes osteopenia. J Cell Physiol 2015; 230:1689-95. [PMID: 25573264 DOI: 10.1002/jcp.24928] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 01/08/2023]
Abstract
Nuclear factor of activated T-cells (Nfat) c1 to c4 are transcription factors that play an undisputable role in osteoclastogenesis. However, Nfat function in osteoblastic cells is controversial. Constitutive activation of Nfatc1 and c2 in osteoblasts suppresses cell function, although the study of Nfat in vivo has yielded conflicting results. To establish the consequences of Nfatc2 activation in osteoblasts, we generated transgenic mice where a 3.6 kb fragment of the collagen type I α1 promoter directs expression of a constitutively active Nfatc2 mutant (Col3.6-Nfatc2). The skeletal phenotype of Col3.6-Nfatc2 mice of both sexes and of sex-matched littermate controls was investigated by microcomputed tomography and histomorphometry. Col3.6- Nfatc2 mice were born at the expected Mendelian ratio and appeared normal. Nfatc2 expression was confirmed in parietal bones from 1 and 3 month old transgenic mice. One month old Col3.6-Nfatc2 female mice exhibited cancellous bone compartment osteopenia secondary to a 30% reduction in bone formation. In contrast, cancellous femoral bone volume and bone formation were not altered in male transgenics, whereas osteoblast number was higher, suggesting incomplete osteoblast maturation. Indices of bone resorption were not affected in either sex. At 3 months of age, the skeletal phenotype evolved; and Col3.6-Nfatc2 male mice exhibited vertebral osteopenia, whereas femoral cancellous bone was not affected in either sex. Nfatc2 activation in osteoblasts had no impact on cortical bone structure. Nfatc2 activation inhibited alkaline phosphatase activity and mineralized nodule formation in bone marrow stromal cell cultures. In conclusion, Nfatc2 activation in osteoblasts inhibits bone formation and causes cancellous bone osteopenia.
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Affiliation(s)
- Stefano Zanotti
- Departments of Orthopaedic Surgery and Medicine, UConn Health Center, Farmington, Connecticut
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19
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Ng AH, Willett TL, Alman BA, Grynpas MD. Development, validation and characterization of a novel mouse model of Adynamic Bone Disease (ABD). Bone 2014; 68:57-66. [PMID: 25111968 DOI: 10.1016/j.bone.2014.07.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 11/29/2022]
Abstract
The etiology of Adynamic Bone Disease (ABD) is poorly understood but the hallmark of ABD is a lack of bone turnover. ABD occurs in renal osteodystrophy (ROD) and is suspected to occur in elderly patients on long-term anti-resorptive therapy. A major clinical concern of ABD is diminished bone quality and an increased fracture risk. To our knowledge, experimental animal models for ABD other than ROD-ABD have not been developed or studied. The objectives of this study were to develop a mouse model of ABD without the complications of renal ablation, and to characterize changes in bone quality in ABD relative to controls. To re-create the adynamic bone condition, 4-month old female Col2.3Δtk mice were treated with ganciclovir to specifically ablate osteoblasts, and pamidronate was used to inhibit osteoclastic resorption. Four groups of animals were used to characterize bone quality in ABD: Normal bone controls, No Formation controls, No Resorption controls, and an Adynamic group. After a 6-week treatment period, the animals were sacrificed and the bones were harvested for analyses. Bone quality assessments were conducted using established techniques including bone histology, quantitative backscattered electron imaging (qBEI), dual energy X-ray absorptiometry (DXA), microcomputed tomography (microCT), and biomechanical testing. Histomorphometry confirmed osteoblast-related hallmarks of ABD in our mouse model. Bone formation was near complete suppression in the No Formation and Adynamic specimens. Inhibition of bone resorption in the Adynamic group was confirmed by tartrate-resistant acid phosphatase (TRAP) stain. Normal bone mineral density and architecture were maintained in the Adynamic group, whereas the No Formation group showed a reduction in bone mineral content and trabecular thickness relative to the Adynamic group. As expected, the No Formation group had a more hypomineralized profile and the Adynamic group had a higher mean mineralization profile that is similar to suppressed bone turnover in human. This data confirms successful replication of the adynamic bone condition in a mouse without the complication of renal ablation. Our approach is the first model of ABD that uses pharmacological manipulation in a transgenic mouse to mimic the bone cellular dynamics observed in the human ABD condition. We plan to use our mouse model to investigate the adynamic bone condition in aging and to study changes to bone quality and fracture risk as a consequence of over-suppressed bone turnover.
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Affiliation(s)
- Adeline H Ng
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Thomas L Willett
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Benjamin A Alman
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Orthopaedic Surgery, Duke University, Durham, NC, USA
| | - Marc D Grynpas
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
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20
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Local transplantation is an effective method for cell delivery in the osteogenesis imperfecta murine model. INTERNATIONAL ORTHOPAEDICS 2014; 38:1955-62. [PMID: 24384938 DOI: 10.1007/s00264-013-2249-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/03/2013] [Indexed: 12/11/2022]
Abstract
PURPOSE Osteogenesis imperfecta is a serious genetic disorder that results from improper type I collagen production. We aimed to evaluate whether bone marrow stromal cells (BMSC) delivered locally into femurs were able to engraft, differentiate into osteoblasts, and contribute to formation of normal bone matrix in the osteogenesis imperfect murine (oim) model. METHODS Donor BMSCs from bone-specific reporter mice (Col2.3GFP) were expanded in vitro and transplanted into the femoral intramedullary cavity of oim mice. Engraftment was evaluated after four weeks. RESULTS We detected differentiation of donor BMSCs into Col2.3GFP+ osteoblasts and osteocytes in cortical and trabecular bone of transplanted oim femurs. New bone formation was detected by deposition of dynamic label in the proximity to the Col2.3GFP+ osteoblasts, and new bone showed more organized collagen structure and expression of type I α2 collagen. Col2.3GFP cells were not found in the contralateral femur indicating that transplanted osteogenic cells did not disseminate by circulation. No osteogenic engraftment was observed following intravenous transplantation of BMSCs. BMSC cultures derived from transplanted femurs showed numerous Col2.3GFP+ colonies, indicating the presence of donor progenitor cells. Secondary transplantation of cells recovered from recipient femurs and expanded in vitro also showed Col2.3GFP+ osteoblasts and osteocytes confirming the persistence of donor stem/progenitor cells. CONCLUSION We show that BMSCs delivered locally in oim femurs are able to engraft, differentiate into osteoblasts and osteocytes and maintain their progenitor potential in vivo. This suggests that local delivery is a promising approach for introduction of autologous MSC in which mutations have been corrected.
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21
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Cheng S, Kesavan C, Mohan S, Qin X, Alarcon CM, Wergedal J, Xing W. Transgenic overexpression of ephrin b1 in bone cells promotes bone formation and an anabolic response to mechanical loading in mice. PLoS One 2013; 8:e69051. [PMID: 23874863 PMCID: PMC3708903 DOI: 10.1371/journal.pone.0069051] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 06/04/2013] [Indexed: 11/18/2022] Open
Abstract
To test if ephrin B1 overexpression enhances bone mass, we generated transgenic mice overexpressing ephrin B1 under the control of a 3.6 kb rat collagen 1A1 promoter (Col3.6-Tgefnb1). Col3.6-Tgefnb1 mice express 6-, 12- and 14-fold greater levels of full-length ephrin B1 protein in bone marrow stromal cells, calvarial osteoblasts, and osteoclasts, respectively. The long bones of both genders of Col3.6-Tgefnb1 mice have increased trabecular bone volume, trabecular number, and trabecular thickness and decreased trabecular separation. Enhanced bone formation and decreased bone resorption contributed to this increase in trabecular bone mass in Col3.6-Tgefnb1 mice. Consistent with these findings, our in vitro studies showed that overexpression of ephrin B1 increased osteoblast differentiation and mineralization, osterix and collagen 1A1 expression in bone marrow stromal cells. Interaction of ephrin B1 with soluble clustered EphB2-Fc decreased osteoclast precursor differentiation into multinucleated cells. Furthermore, we demonstrated that the mechanical loading-induced increase in EphB2 expression and newly formed bone were significantly greater in the Col3.6-Tgefnb1 mice than in WT littermate controls. Our findings that overexpression of ephrin B1 in bone cells enhances bone mass and promotes a skeletal anabolic response to mechanical loading suggest that manipulation of ephrin B1 actions in bone may provide a means to sensitize the skeleton to mechanical strain to stimulate new bone formation.
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Affiliation(s)
- Shaohong Cheng
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
| | - Chandrasekhar Kesavan
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
- Department of Biochemistry, Loma Linda University, Loma Linda, California, United States of America
- Department of Physiology, Loma Linda University, Loma Linda, California, United States of America
| | - Xuezhong Qin
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Catrina M. Alarcon
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
| | - Jon Wergedal
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
- Department of Biochemistry, Loma Linda University, Loma Linda, California, United States of America
| | - Weirong Xing
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
- * E-mail:
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Murao H, Yamamoto K, Matsuda S, Akiyama H. Periosteal cells are a major source of soft callus in bone fracture. J Bone Miner Metab 2013; 31:390-8. [PMID: 23475152 DOI: 10.1007/s00774-013-0429-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 01/24/2013] [Indexed: 12/26/2022]
Abstract
During the healing process after bone fracture, soft callus forms adjacent to the fracture site, is replaced by hard callus, and is finally remodeled to the original bone configuration. Although the cambium layer of the periosteum is reported to play an essential role in callus formation, we still lack direct in vivo evidence of this. To investigate the cell lineage of the soft callus, we analyzed the process of fracture healing in Prx1-Cre;ROSA26 reporter (R26R), Col1a1(3.6 kb)-Cre;R26R, Col1a1(2.3 kb)-Cre;R26R, Sox9-CreERT2;R26R, and Sox9-LacZ mice with X-gal staining. In the Prx1-Cre;R26R, in which the cells of the periosteum stained for X-gal before fracture, all cells in the soft callus were X-gal positive, whereas in the Col1a1(3.6 kb)-Cre;R26R mice, the cells in the periosteum before fracture stained for X-gal and the soft callus was partly composed of X-gal-positive cells. In contrast, in the Col1a1(2.3 kb)-Cre;R26R mice, in which the mature osteoblasts in the cambium layer of the periosteum were marked before fracture, no cells in the soft callus at the fracture site were X-gal positive. These results suggest that most of the cells in the soft callus are derived from the mesenchymal progenitors in the periosteum, and not from mature osteoblastic cells. Interestingly, in the Sox9-LacZ mice, Sox9-expressing X-gal-positive cells emerged in the periosteum adjacent to the fracture site 3 days after fracture. We demonstrated this by injecting tamoxifen into the Sox9-CreERT2;R26R mice for 3 days after fracture, so that these Sox9-expressing periosteal cells gave rise to cells in the soft and hard calli. Our findings show that the periosteal cells in which Sox9 expression is induced just after fracture are the major source of the chondrocytes and osteoblasts in the fracture callus.
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Affiliation(s)
- Hiroki Murao
- Department of Orthopaedics, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto, Japan
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23
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Wan Y, Lu C, Cao J, Zhou R, Yao Y, Yu J, Zhang L, Zhao H, Li H, Zhao J, Zhu X, He L, Liu Y, Yao Z, Yang X, Guo X. Osteoblastic Wnts differentially regulate bone remodeling and the maintenance of bone marrow mesenchymal stem cells. Bone 2013; 55:258-67. [PMID: 23334081 DOI: 10.1016/j.bone.2012.12.052] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/28/2012] [Accepted: 12/31/2012] [Indexed: 12/29/2022]
Abstract
Wnt signaling has important roles in embryonic bone development and postnatal bone remodeling, but inconsistent impact on bone property is observed in different genetic alterations of Lrp5 and β-catenin. More importantly, it is still controversial whether Lrp5 regulate bone formation locally or globally through gut-derived serotonin. Here we explored the function of Wnt proteins in osteoblastic niche through inactivation of the Wntless (Wls) gene, which abrogates the secretion of Wnts. The depletion of Wls in osteoblast progenitor cells resulted in severe osteopenia with more profound defects in osteoblastogenesis, osteoclastogenesis and maintenance of bone marrow mesenchymal stem cells (BMSCs) compared to that observed in Lrp5 and β-catenin mutants. These findings support the point of view that Wnt/Lrp5 signaling locally regulates bone mass accrual through multiple effects of osteoblastic Wnts on osteoblastic bone formation and osteoclastic bone resorption. Moreover, osteoblastic Wnts confer a niche role for maintenance of BMSCs, providing novel cues for the definition of BMSCs niche in bone marrow.
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Affiliation(s)
- Yong Wan
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200240, China
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Zanotti S, Canalis E. Hairy and Enhancer of Split-related with YRPW motif (HEY)2 regulates bone remodeling in mice. J Biol Chem 2013; 288:21547-57. [PMID: 23782701 DOI: 10.1074/jbc.m113.489435] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Notch induces Hairy and Enhancer of Split-related with YRPW motif (Hey)1, Hey2, and HeyL expression in osteoblasts, but the contributions of these genes to the skeletal effects of Notch are not fully understood. HEY1 misexpression has limited skeletal impact, female HeyL null mice display increased bone mass, and Hey2 inactivation is developmentally lethal. To inactivate Hey2 in immature or mature osteoblasts, Hey2(loxP/loxP) mice were crossed with transgenics expressing CRE under the control of the osterix (Osx-Cre) or osteocalcin (Oc-Cre) promoters to generate Osx-Cre(+/-);Hey2(Δ/Δ) or Oc-Cre(+/-);Hey2(Δ/Δ) mice. Trabecular bone volume increased in 3-month-old Osx-Cre(+/-);Hey2(Δ/Δ) and Oc-Cre(+/-);Hey2(Δ/Δ) male mice and in 1-month-old Oc-Cre(+/-);Hey2(Δ/Δ) female mice, although 3-month-old Oc-Cre(+/-);Hey2(Δ/Δ) females developed osteopenia. Alkaline phosphatase liver/bone/kidney (ALPL) expression and activity were suppressed in osteoblasts from Oc-Cre(+/-);Hey2(Δ/Δ) mice of both sexes. To overexpress HEY2 in osteoblasts, transgenic mice where a 3.6-kb fragment of the rat collagen type-I α1 promoter directs HEY2 expression were created. Three-month-old Hey2 transgenic males exhibited decreased osteoblast activity and increased bone resorption and developed osteopenia at 6 months of age. Hey2 transgenic females exhibited reduced osteoblast number and function, but no changes in bone resorption. HEY2 overexpression in osteoblasts from mice of both sexes inhibited ALPL expression and activity and suppressed osteocalcin transcripts in cells from male mice only. HEY2 overexpression in osteoblasts from male mice enhanced bone resorption by co-cultured splenocytes and induced interleukin-6, a molecule that promotes osteoclastogenesis. In conclusion, HEY2 decreases skeletal mass and regulates bone remodeling in male mice.
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Affiliation(s)
- Stefano Zanotti
- Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105-1299, USA
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Jacome-Galarza CE, Lee SK, Lorenzo JA, LeonardoAguila H. Identification, characterization, and isolation of a common progenitor for osteoclasts, macrophages, and dendritic cells from murine bone marrow and periphery. J Bone Miner Res 2013; 28:1203-13. [PMID: 23165930 PMCID: PMC3625454 DOI: 10.1002/jbmr.1822] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/18/2012] [Accepted: 11/05/2012] [Indexed: 12/11/2022]
Abstract
Osteoclasts are specialized bone-resorbing cells that derive from monocyte precursors. We have identified three populations of cells with high osteoclastogenic potential in murine bone marrow, which expressed the phenotype B220(-) CD3(-) CD11b(-/low) CD115(+) and either CD117(hi), CD117(intermediate), or CD117(low). We have evaluated these populations for their ability to also generate macrophages and dendritic cells. At a single-cell level, the population expressing higher CD117 levels was able to generate bone-resorbing osteoclasts, phagocytic macrophages, and antigen-presenting dendritic cells in vitro with efficiencies of more than 90%, indicating that there exists a common developmental pathway for these cell types. Cells with osteoclastogenic potential also exist in blood and peripheral hematopoietic organs. Their functional meaning and/or their relationship with bone marrow progenitors is not well established. Hence, we characterized murine peripheral cell populations for their ability to form osteoclasts, macrophages, and dendritic cells in vitro. The spleen and peripheral blood monocyte progenitors share phenotypic markers with bone marrow progenitors but differ in their expression of CD11b, which was low in bone marrow but high in periphery. We propose that circulating monocyte progenitors are derived from a common bone marrow osteoclasts/macrophage/dendritic cell progenitor (OcMDC), which we have now characterized at a clonal level. However, the lineage relationship between the bone marrow and peripheral monocyte progenitors has yet to be defined.
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Affiliation(s)
| | - Sun-Kyeong Lee
- Department of Medicine, University of Connecticut Health Center. Farmington, CT, USA
| | - Joseph A. Lorenzo
- Department of Medicine, University of Connecticut Health Center. Farmington, CT, USA
| | - Hector LeonardoAguila
- Department of Immunology, University of Connecticut Health Center. Farmington, CT, USA
- Department of Medicine, University of Connecticut Health Center. Farmington, CT, USA
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26
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Su N, Chen M, Chen S, Li C, Xie Y, Zhu Y, Zhang Y, Zhao L, He Q, Du X, Chen D, Chen L. Overexpression of H1 calponin in osteoblast lineage cells leads to a decrease in bone mass by disrupting osteoblast function and promoting osteoclast formation. J Bone Miner Res 2013; 28:660-71. [PMID: 23044709 PMCID: PMC3716280 DOI: 10.1002/jbmr.1778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 08/24/2012] [Accepted: 09/07/2012] [Indexed: 02/03/2023]
Abstract
H1 calponin (CNN1) is known as a smooth muscle-specific, actin-binding protein which regulates smooth muscle contractive activity. Although previous studies have shown that CNN1 has effect on bone, the mechanism is not well defined. To investigate the role of CNN1 in maintaining bone homeostasis, we generated transgenic mice overexpressing Cnn1 under the control of the osteoblast-specific 3.6-kb Col1a1 promoter. Col1a1-Cnn1 transgenic mice showed delayed bone formation at embryonic stage and decreased bone mass at adult stage. Morphology analyses showed reduced trabecular number, thickness and defects in bone formation. The proliferation and migration of osteoblasts were decreased in Col1a1-Cnn1 mice due to alterations in cytoskeleton. The early osteoblast differentiation of Col1a1-Cnn1 mice was increased, but the late stage differentiation and mineralization of osteoblasts derived from Col1a1-Cnn1 mice were significantly decreased. In addition to impaired bone formation, the decreased bone mass was also associated with enhanced osteoclastogenesis. Tartrate-resistant acid phosphatase (TRAP) staining revealed increased osteoclast numbers in tibias of 2-month-old Col1a1-Cnn1 mice, and increased numbers of osteoclasts co-cultured with Col1a1-Cnn1 osteoblasts. The ratio of RANKL to OPG was significantly increased in Col1a1-Cnn1 osteoblasts. These findings reveal a novel function of CNN1 in maintaining bone homeostasis by coupling bone formation to bone resorption.
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Affiliation(s)
- Nan Su
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Maomao Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Siyu Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Can Li
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yangli Xie
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Ying Zhu
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yaozong Zhang
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Ling Zhao
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Qifen He
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Xiaolan Du
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Di Chen
- Department of Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Lin Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
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Yang JY, Cho SW, An JH, Jung JY, Kim SW, Kim SY, Kim JE, Shin CS. Osteoblast-targeted overexpression of TAZ increases bone mass in vivo. PLoS One 2013; 8:e56585. [PMID: 23441207 PMCID: PMC3575506 DOI: 10.1371/journal.pone.0056585] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 01/11/2013] [Indexed: 01/28/2023] Open
Abstract
Osteoblasts are derived from mesenchymal progenitors. Differentiation to osteoblasts and adipocytes is reciprocally regulated. Transcriptional coactivator with a PDZ-binding motif (TAZ) is a transcriptional coactivator that induces differentiation of mesenchymal cells into osteoblasts while blocking differentiation into adipocytes. To investigate the role of TAZ on bone metabolism in vivo, we generated transgenic mice that overexpress TAZ under the control of the procollagen type 1 promoter (Col1-TAZ). Whole body bone mineral density (BMD) of 6- to 19-week-old Col-TAZ mice was 4% to 7% higher than that of their wild-type (WT) littermates, whereas no difference was noticed in Col.1-TAZ female mice. Microcomputed tomography analyses of proximal tibiae at 16 weeks of age demonstrated a significant increase in trabecular bone volume (26.7%) and trabecular number (26.6%) with a reciprocal decrease in trabecular spacing (14.2%) in Col1-TAZ mice compared with their WT littermates. In addition, dynamic histomorphometric analysis of the lumbar spine revealed increased mineral apposition rate (42.8%) and the serum P1NP level was also significantly increased (53%) in Col.1-TAZ mice. When primary calvaria cells were cultured in osteogenic medium, alkaline phosphatase (ALP) activity was significantly increased and adipogenesis was significantly suppressed in Col1-TAZ mice compared with their WT littermates. Quantitative real-time polymerase chain reaction analyses showed that expression of collagen type 1, bone sialoprotein, osteocalcin, ALP, osterix, and Runx2 was significantly increased in calvaria cells from Col1-TAZ mice compared to their WT littermates. In vitro, TAZ enhanced Runx2-mediated transcriptional activity while suppressing the peroxisome proliferator-activated receptor gamma signaling pathway. TAZ also enhanced transcriptional activity from 3TP-Lux, which reflects transforming growth factor-beta (TGF-β)-mediated signaling. In addition, TAZ enhanced TGF-β-dependent nuclear translocation of Smad2/3 and Smad4. Taken together, these results suggest that TAZ positively regulates bone formation in vivo, which seems to be mediated by enhancing both Runx2 and TGF-β signaling.
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Affiliation(s)
- Jae-Yeon Yang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sun Wook Cho
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jee Hyun An
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Ju Yeon Jung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sang Wan Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Seong Yeon Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jung Eun Kim
- Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Korea
| | - Chan Soo Shin
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
- * E-mail:
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28
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Kotani M, Kikuta J, Klauschen F, Chino T, Kobayashi Y, Yasuda H, Tamai K, Miyawaki A, Kanagawa O, Tomura M, Ishii M. Systemic circulation and bone recruitment of osteoclast precursors tracked by using fluorescent imaging techniques. THE JOURNAL OF IMMUNOLOGY 2012; 190:605-12. [PMID: 23241888 DOI: 10.4049/jimmunol.1201345] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Osteoclasts are bone-resorbing polykaryons differentiated from monocyte/macrophage-lineage hematopoietic precursors. It remains unclear whether osteoclasts originate from circulating blood monocytes or from bone tissue-resident precursors. To address this question, we combined two different experimental procedures: 1) shared blood circulation "parabiosis" with fluorescently labeled osteoclast precursors, and 2) photoconversion-based cell tracking with a Kikume Green-Red protein (KikGR). In parabiosis, CX(3)CR1-EGFP knock-in mice in which osteoclast precursors were labeled with EGFP were surgically connected with wild-type mice to establish a shared circulation. Mature EGFP(+) osteoclasts were found in the bones of the wild-type mice, indicating the mobilization of EGFP(+) osteoclast precursors into bones from systemic circulation. Receptor activator for NF-κB ligand stimulation increased the number of EGFP(+) osteoclasts in wild-type mice, suggesting that this mobilization depends on the bone resorption state. Additionally, KikGR(+) monocytes (including osteoclast precursors) in the spleen were exposed to violet light, and 2 d later we detected photoconverted "red" KikGR(+) osteoclasts along the bone surfaces. These results indicate that circulating monocytes from the spleen entered the bone spaces and differentiated into mature osteoclasts during a certain period. The current study used fluorescence-based methods clearly to demonstrate that osteoclasts can be generated from circulating monocytes once they home to bone tissues.
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Affiliation(s)
- Manato Kotani
- Laboratory of Cellular Dynamics, World Premier International Research Center Initiative-Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
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29
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Ohishi M, Ono W, Ono N, Khatri R, Marzia M, Baker EK, Root SH, Wilson TLS, Iwamoto Y, Kronenberg HM, Aguila HL, Purton LE, Schipani E. A novel population of cells expressing both hematopoietic and mesenchymal markers is present in the normal adult bone marrow and is augmented in a murine model of marrow fibrosis. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:811-8. [PMID: 22155108 DOI: 10.1016/j.ajpath.2011.10.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 09/29/2011] [Accepted: 10/31/2011] [Indexed: 01/13/2023]
Abstract
Bone marrow (BM) fibrosis is a feature of severe hyperparathyroidism. Consistent with this observation, mice expressing constitutively active parathyroid hormone (PTH)/PTH-related peptide receptors (PPR) in osteoblasts (PPR*Tg) display BM fibrosis. To obtain insight into the nature of BM fibrosis in such a model, a double-mutant mouse expressing constitutively active PPR and green fluorescent protein (GFP) under the control of the type I collagen promoter (PPR*Tg/GFP) was generated. Confocal microscopy and flow cytometry revealed the presence of a cell population expressing GFP (GFP(+)) that was also positive for the hematopoietic marker CD45 in the BM of both PPR*Tg/GFP and control animals. This cell population was expanded in PPR*Tg/GFP. The existence of cells expressing both type I collagen and CD45 in the adult BM was confirmed by IHC and fluorescence-activated cell sorting. An analysis of total RNA extracted from sorted GFP(+)CD45(+) cells showed that these cells produced type I collagen and PTH/PTH-related peptide receptor and receptor activator for NF-κB mRNAs, further supporting their features of being both mesenchymal and hematopoietic lineages. Similar cells, known as fibrocytes, are also present in pathological fibroses. Our findings, thus, indicate that the BM is a permissive microenvironment for the differentiation of fibrocyte-like cells and raise the possibility that these cells could contribute to the pathogenesis of BM fibrosis.
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Affiliation(s)
- Masanobu Ohishi
- Endocrine Unit, the Department of Medicine, Faculty of Medical Sciences, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
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Elefteriou F, Yang X. Genetic mouse models for bone studies--strengths and limitations. Bone 2011; 49:1242-54. [PMID: 21907838 PMCID: PMC3331798 DOI: 10.1016/j.bone.2011.08.021] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/15/2011] [Accepted: 08/18/2011] [Indexed: 11/25/2022]
Abstract
Mice have become a preferred model system for bone research because of their genetic and pathophysiological similarities to humans: a relatively short reproductive period, leading to relatively low cost of maintenance and the availability of the entire mouse genome sequence information. The success in producing the first transgenic mouse line that expressed rabbit β-globin protein in mouse erythrocytes three decades ago marked the beginning of the use of genetically engineered mice as model system to study human diseases. Soon afterward the development of cultured pluripotent embryonic stem cells provided the possibility of gene replacement or gene deletion in mice. These technologies have been critical to identify new genes involved in bone development, growth, remodeling, repair, and diseases, but like many other approaches, they have limitations. This review will introduce the approaches that allow the generation of transgenic mice and global or conditional (tissue-specific and inducible) mutant mice. A list of the various promoters used to achieve bone-specific gene deletion or overexpression is included. The limitations of these approaches are discussed, and general guidelines related to the analysis of genetic mouse models are provided.
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Affiliation(s)
- Florent Elefteriou
- Vanderbilt University Medical Center, Department of Medicine, Vanderbilt Center for Bone Biology, 1235H Light Hall, Nashville, TN 37232-0575, USA
| | - Xiangli Yang
- Vanderbilt University Medical Center, Department of Medicine, Vanderbilt Center for Bone Biology, 1235H Light Hall, Nashville, TN 37232-0575, USA
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Balic A, Aguila HL, Mina M. Identification of cells at early and late stages of polarization during odontoblast differentiation using pOBCol3.6GFP and pOBCol2.3GFP transgenic mice. Bone 2010; 47:948-58. [PMID: 20728593 PMCID: PMC2957651 DOI: 10.1016/j.bone.2010.08.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 02/09/2023]
Abstract
Transgenic mouse lines in which GFP expression is under the control of tissue- and stage specific promoters have provided powerful experimental tools for identification and isolation of cells at specific stage of differentiation along a lineage. In the present study, we used primary cell cultures derived from the dental pulp from pOBCol3.6GFP and pOBCol2.3GFP transgenic mice as a model to develop markers for early stages of odontoblast differentiation from progenitor cells. We analyzed the temporal and spatial expression of 2.3-GFP and 3.6-GFP during in vitro mineralization. Using FACS to separate cells based on GFP expression, we obtained relatively homogenous subpopulations of cells and analyzed their dentinogenic potentials and their progression into odontoblasts. Our observations showed that these transgenes were activated before the onset of matrix deposition and in cells at different stages of polarization. The 3.6-GFP transgene was activated in cells in early stages of polarization, whereas the 2.3-GFP transgene was activated at a later stage of polarization just before or at the time of formation of secretory odontoblast.
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Affiliation(s)
- Anamaria Balic
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
| | - H. Leonardo Aguila
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Mina Mina
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
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Yang M, Trettel LB, Adams DJ, Harrison JR, Canalis E, Kream BE. Col3.6-HSD2 transgenic mice: a glucocorticoid loss-of-function model spanning early and late osteoblast differentiation. Bone 2010; 47:573-82. [PMID: 20541046 PMCID: PMC2926146 DOI: 10.1016/j.bone.2010.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 05/26/2010] [Accepted: 06/01/2010] [Indexed: 01/08/2023]
Abstract
The goal of this study was to characterize the bone phenotype and molecular alterations in Col3.6-HSD2 mice in which a 3.6-kb Col1a1 promoter fragment drives 11beta-HSD2 expression broadly in the osteoblast lineage to reduce glucocorticoid signaling. Serum corticosterone was unchanged in transgenic females excluding a systemic effect of the transgene. Adult transgenic mice showed reduced vertebral trabecular bone volume and reduced femoral and tibial sub-periosteal and sub-endosteal areas as assessed by microCT. In adult female transgenic mice, histomorphometry showed that vertebral bone mass and trabecular number were reduced but that osteoblast and osteoclast numbers and the mineral apposition and bone formation rates were not changed, suggesting a possible developmental defect in the formation of trabeculae. In a small sample of male mice, osteoblast number and percent osteoid surface were increased but the mineral apposition bone formation rates were not changed, indicating subtle sex-specific phenotypic differences in Col3.6-HSD2 bone. Serum from transgenic mice had decreased levels of the C-terminal telopeptide of alpha1(I) collagen but increased levels of osteocalcin. Transgenic calvarial osteoblast and bone marrow stromal cultures showed decreased alkaline phosphatase and mineral staining, reduced levels of Col1a1, bone sialoprotein and osteocalcin mRNA expression, and decreased cell growth and proliferation. Transgenic bone marrow cultures treated with RANKL and M-CSF showed greater osteoclast formation; however, osteoclast activity as assessed by resorption of a calcium phosphate substrate was decreased in transgenic cultures. Gene profiling of cultured calvarial osteoblasts enriched in the Col3.6-HSD2 transgene showed modest but significant changes in gene expression, particularly in cell cycle and integrin genes. In summary, Col3.6-HSD2 mice showed a low bone mass phenotype, with decreased ex vivo osteogenesis. These data further strengthen the concept that endogenous glucocorticoid signaling is required for optimal bone mass acquisition and highlight the complexities of glucocorticoid signaling in bone cell lineages.
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Affiliation(s)
- Maobin Yang
- Department of Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Lorin B. Trettel
- Department of Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Douglas J. Adams
- Department of Orthopaedic Surgery, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - John R. Harrison
- Department of Craniofacial Sciences, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Ernesto Canalis
- Department of Research, Saint Francis Hospital and Medical Center, 114 Woodland, Street Hartford, Hartford, CT 06105-1299
| | - Barbara E. Kream
- Department of Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
- Department of Orthopaedic Surgery, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA, and Department of Research, Saint Francis Hospital and Medical Center, 114 Woodland, Street Hartford, Hartford, CT 06105-1299
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Boban I, Barisic-Dujmovic T, Clark SH. Parabiosis model does not show presence of circulating osteoprogenitor cells. Genesis 2010; 48:171-82. [PMID: 20127800 DOI: 10.1002/dvg.20602] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The goal of this study was to determine the presence of osteoprogenitor cells in the peripheral blood. Experiments were conducted with a parabiosis model in which osteoblast specific transgenic mice (Col2.3GFP or hOC-GFP) were surgically joined with a transgenic mouse where herpes virus thymidine kinase gene is under the control of the collagen alpha1 promoter (Col2.3DeltaTK). This method permits conditional ablation of osteoblasts by ganciclovir (GCV) treatment. In parabionts treated with GCV for 15 days or 1.5-2 months, GFP (hOC-GFP or Col2.3GFP) expression was not detected in histological preparations or in marrow stromal cell cultures from the Col2.3DeltaTK parabiont. Finally, Col2.3GFP/Col2.3DeltaTK pairs were treated with GCV for 15 days and allowed to recover from GCV for 3 months. Again there was a failure to detect Col2.3GFP expressing cells in the Col2.3DeltaTK parabiont. These observations, at least within the limits of this model system, allow the conclusion that osteoprogenitor cells do not readily circulate.
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Affiliation(s)
- Ivana Boban
- Department of Genetics and Developmental Biology, University of Connecticut Stem Cell Institute, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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34
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Balic A, Aguila HL, Caimano MJ, Francone VP, Mina M. Characterization of stem and progenitor cells in the dental pulp of erupted and unerupted murine molars. Bone 2010; 46:1639-51. [PMID: 20193787 PMCID: PMC2881695 DOI: 10.1016/j.bone.2010.02.019] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/12/2010] [Accepted: 02/18/2010] [Indexed: 12/15/2022]
Abstract
In the past few years there have been significant advances in the identification of putative stem cells also referred to as "mesenchymal stem cells" (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulps from erupted molars displayed a reduced number of cells, contained a higher percentage of CD45+ and a lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and were infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts.
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Affiliation(s)
- Anamaria Balic
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
| | - H. Leonardo Aguila
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Melissa J. Caimano
- Department of Medicine, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Victor P. Francone
- Department of Neuroscience, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Mina Mina
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
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35
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Wang CJ, Chen IP, Koczon-Jaremko B, Boskey AL, Ueki Y, Kuhn L, Reichenberger EJ. Pro416Arg cherubism mutation in Sh3bp2 knock-in mice affects osteoblasts and alters bone mineral and matrix properties. Bone 2010; 46:1306-15. [PMID: 20117257 PMCID: PMC2854251 DOI: 10.1016/j.bone.2010.01.380] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/15/2010] [Accepted: 01/21/2010] [Indexed: 11/22/2022]
Abstract
Cherubism is an autosomal dominant disorder in children characterized by unwarranted symmetrical bone resorption of the jaws with fibrous tissue deposition. Mutations causing cherubism have been identified in the adaptor protein SH3BP2. Knock-in mice with a Pro416Arg mutation in Sh3bp2 exhibit a generalized osteoporotic bone phenotype. In this study, we examined the effects of this "cherubism" mutation on spectroscopic indices of "bone quality" and on osteoblast differentiation. Fourier-transform infrared imaging (FTIRI) analysis of femurs from wild-type and Sh3bp2 knock-in mice showed decreased mineral content, decreased mineral crystallinity/crystal size, and increased collagen maturity in homozygous mutants. To assess osteoblast maturation in vivo, knock-in mice were crossed with transgenic mice over-expressing GFP driven by 3.6-kb or 2.3-kb Col1a1 promoter fragments. Reduced numbers of mature osteoblasts were observed in homozygous mice. Neonatal calvarial cultures, which were enriched for osteoblasts by depletion of hematopoietic cells (negative selection for Ter119- and CD45-positive cells) were investigated for osteoblast-specific gene expression and differentiation, which demonstrated that differentiation and mineralization in homozygous osteoblast cultures was impaired. Co-cultures with calvarial osteoblasts and bone marrow macrophages showed that mutant osteoblasts appear to increase osteoclastogenesis resulting in increased bone resorption on bone chips. In summary, the Sh3bp2 mutation in cherubism mice alters bone quality, reduces osteoblast function, and may contribute to excessive bone resorption by osteoclasts. Our data, together with previous osteoclast studies, demonstrate a critical role of Sh3bp2 in bone remodeling and osteoblast differentiation.
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Affiliation(s)
- Chiachien J Wang
- Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
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36
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Liu J, Arends R, Martens A, den Brok-Bardoel MHC, Scheepers MGH, van Blitterswijk CA, de Boer J. Noninvasive imaging of bone-specific collagen I expression in a luciferase transgenic mouse model. Tissue Eng Part C Methods 2010; 16:1297-304. [PMID: 20218816 DOI: 10.1089/ten.tec.2009.0594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Luciferase transgenic mice are a very promising tool for noninvasive, quantitative, and longitudinal evaluation of gene expression. The aim of this study was to validate the Col(I)-Luc transgenic mouse model in which the luciferase gene is driven by bone-specific regulatory elements from the mouse collagen α1(I) gene for bioluminescent imaging of bone development and remodeling. We observed strong luciferase activity in skeletal tissues of Col(I)-Luc mice, and observed that the light intensity declined with postnatal bone development. Luciferase activity was enhanced in a tail bone repair model and we were able to monitor the process of ectopic bone formation induced by recombinant human bone morphogenetic protein 2 using bioluminescent imaging. We conclude that Col(I)-Luc transgenic mice can be applied in the field of bone tissue engineering for monitoring bone repair processes and for investigating osteoinductive molecules or scaffolds.
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Affiliation(s)
- Jun Liu
- Department of Tissue Regeneration, MIRA Research Institute, University of Twente, Enschede, The Netherlands
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37
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Kim S, von Recum HA. Endothelial progenitor populations in differentiating embryonic stem cells I: Identification and differentiation kinetics. Tissue Eng Part A 2010; 15:3709-18. [PMID: 19514847 DOI: 10.1089/ten.tea.2008.0659] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Embryonic stem cells (ESCs) have enormous potential in tissue engineering and cell therapies. However, the therapeutic use of ESCs has been restricted because of the presence of undifferentiated cells or cells with undesired phenotypes. We have explored identifying and selecting endothelial cells (ECs) using green fluorescent protein (GFP) under the control of different endothelial promoters. This method can result in progenitor populations that differ based on promoter activity; however, there have not been rigorous studies comparing differentiation kinetics and selection using these promoters as well as the resulting phenotype. In this study, we examined differentiation profiles of ESCs selected using three different endothelial promoters (Flk1, PECAM, and Tie1) that correspond to endothelial proteins expressed at different time points (early, middle, and late) in ESC differentiation. All three promoters yielded cells with EC-specific protein expression and DiI-Ac-LDL uptake when sorted for GFP(+) population; however, Flk1-driven GFP(+) cells yielded both smooth muscle cells and ECs or progenitors, whereas Tie1-driven GFP(+) cells yielded mostly endothelial phenotype. Both Flk1 and PECAM promoters showed a noticeable level of GFP expression while in the undifferentiated state, making the elimination of undifferentiated cells difficult. Our findings show the differentiation kinetics of the various EC promoters and how different endothelial promoters can be used to select distinct subpopulations of ECs and endothelial precursors across a spectrum of differentiation.
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Affiliation(s)
- Saejeong Kim
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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38
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Barisic-Dujmovic T, Boban I, Clark SH. Fibroblasts/myofibroblasts that participate in cutaneous wound healing are not derived from circulating progenitor cells. J Cell Physiol 2010; 222:703-12. [PMID: 20020505 DOI: 10.1002/jcp.21997] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dermal fibroblasts/myofibroblasts involved in the wound healing are thought to originate from the resident fibroblast progenitors. To test the hypothesis of an extra dermal origin of the dermal fibroblasts/myofibroblasts, bone marrow (BM) transplantation and parabiosis experiments were initiated utilizing a collagen promoter green fluorescent protein (GFP) reporter transgene as a visible marker for dermal fibroblasts/myofibroblasts. BM transplantation experiments using BM from Col3.6GFPsapph transgenic mice showed no evidence that BM derived progenitors differentiated into dermal fibroblasts/myofibroblasts at the wound site. Rather the GFP positive cells (GFP+) observed at the wound site were not dermal fibroblasts/myofibroblasts but immune cells. These GFP+ cells were also detected in the lung and spleen. Furthermore, GFP+ fibroblasts were not detected in primary dermal fibroblast cultures initiated from BM chimeras. Using the same transgenic mice, parabiotic pairs were generated. One partner in the parabiosis carried a GFP expressing transgene while the other partner was a non-transgenic C57BL/6 mouse. Similar to the BM transplantation experiments, GFP+ immune cells were detected in the wound of the non-transgenic parabiont, however, GFP expressing dermal fibroblasts/myofibroblasts were not observed. Collectively, these data suggest that dermal fibroblast/myofibroblast progenitors do not readily circulate. The expression of the Col3.6GFPsapph in the hematopoietic cells confirmed that our methods were sensitive enough to detect Col3.6GFP expressing dermal fibroblasts derived from the peripheral circulation if they had originated in the BM.
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Affiliation(s)
- Tatjana Barisic-Dujmovic
- Department of Genetics and Developmental Biology, University of Connecticut Stem Cell Institute, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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39
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Ephrin B1 regulates bone marrow stromal cell differentiation and bone formation by influencing TAZ transactivation via complex formation with NHERF1. Mol Cell Biol 2009; 30:711-21. [PMID: 19995908 DOI: 10.1128/mcb.00610-09] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mutations of ephrin B1 in humans result in craniofrontonasal syndrome. Because little is known of the role and mechanism of action of ephrin B1 in bone, we examined the function of osteoblast-produced ephrin B1 in vivo and identified the molecular mechanism by which ephrin B1 reverse signaling regulates bone formation. Targeted deletion of the ephrin B1 gene in type 1alpha2 collagen-producing cells resulted in severe calvarial defects, decreased bone size, bone mineral density, and trabecular bone volume, caused by impairment in osterix expression and osteoblast differentiation. Coimmunoprecipitation of the TAZ complex with TAZ-specific antibody revealed a protein complex containing ephrin B1, PTPN13, NHERF1, and TAZ in bone marrow stromal (BMS) cells. Activation of ephrin B1 reverse signaling with soluble EphB2-Fc led to a time-dependent increase in TAZ dephosphorylation and shuttling from cytoplasm to nucleus. Treatment of BMS cells with exogenous EphB2-Fc resulted in a 4-fold increase in osterix expression as determined by Western blotting. Disruption of TAZ expression using specific lentivirus small hairpin RNA (shRNA) decreased TAZ mRNA by 80% and ephrin B1 reverse signaling-mediated increases in osterix mRNA by 75%. Knockdown of NHERF1 expression reduced basal levels of osterix expression by 90% and abolished ephrin B1-mediated induction of osterix expression. We conclude that locally produced ephrin B1 mediates its effects on osteoblast differentiation by a novel molecular mechanism in which activation of reverse signaling leads to dephosphorylation of TAZ and subsequent release of TAZ from the ephrin B1/NHERF1/TAZ complex to translocate to the nucleus to induce expression of the osterix gene and perhaps other osteoblast differentiation genes. Our findings provide strong evidence that ephrin B1 reverse signaling in osteoblasts is critical for BMS cell differentiation and bone formation.
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Wiren KM, Semirale AA, Zhang XW, Woo A, Tommasini SM, Price C, Schaffler MB, Jepsen KJ. Targeting of androgen receptor in bone reveals a lack of androgen anabolic action and inhibition of osteogenesis: a model for compartment-specific androgen action in the skeleton. Bone 2008; 43:440-51. [PMID: 18595795 PMCID: PMC2574646 DOI: 10.1016/j.bone.2008.04.026] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 04/16/2008] [Accepted: 04/23/2008] [Indexed: 10/22/2022]
Abstract
Androgens are anabolic hormones that affect many tissues, including bone. However, an anabolic effect of androgen treatment on bone in eugonadal subjects has not been observed and clinical trials have been disappointing. The androgen receptor (AR) mediates biological responses to androgens. In bone tissue, both AR and the estrogen receptor (ER) are expressed. Since androgens can be converted into estrogen, the specific role of the AR in maintenance of skeletal homoeostasis remains controversial. The goal of this study was to use skeletally targeted overexpression of AR in differentiated osteoblasts as a means of elucidating the specific role(s) for AR transactivation in the mature bone compartment. Transgenic mice overexpressing AR under the control of the 2.3-kb alpha1(I)-collagen promoter fragment showed no difference in body composition, testosterone, or 17ss-estradiol levels. However, transgenic males have reduced serum osteocalcin, CTx and TRAPC5b levels, and a bone phenotype was observed. In cortical bone, high-resolution micro-computed tomography revealed no difference in periosteal perimeter but a significant reduction in cortical bone area due to an enlarged marrow cavity. Endocortical bone formation rate was also significantly inhibited. Biomechanical analyses showed decreased whole bone strength and quality, with significant reductions in all parameters tested. Trabecular morphology was altered, with increased bone volume comprised of more trabeculae that were closer together but not thicker. Expression of genes involved in bone formation and bone resorption was significantly reduced. The consequences of androgen action are compartment-specific; anabolic effects are exhibited exclusively at periosteal surfaces, but in mature osteoblasts androgens inhibited osteogenesis with detrimental effects on matrix quality, bone fragility and whole bone strength. Thus, the present data demonstrate that enhanced androgen signaling targeted to bone results in low bone turnover and inhibition of bone formation by differentiated osteoblasts. These results indicate that direct androgen action in mature osteoblasts is not anabolic, and raise concerns regarding anabolic steroid abuse in the developing skeleton or high-dose treatment in eugonadal adults.
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Affiliation(s)
- Kristine M Wiren
- Bone and Mineral Research Unit, Portland Veterans Affairs Medical Center, Portland, Oregon, USA.
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41
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Barisic-Dujmovic T, Boban I, Clark SH. Regulation of collagen gene expression in the Tsk2 mouse. J Cell Physiol 2008; 215:464-71. [PMID: 17960558 DOI: 10.1002/jcp.21319] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The tight skin 2 (Tsk2) mutation is an ENU induced dominant mutation localized on mouse chromosome 1. While the molecular defect is unknown, Tsk2/+ mice display cutaneous thickening associated with excessive matrix production and are used as a model of scleroderma. The purpose of this study was to examine the cellular mechanisms associated with the excessive synthesis of matrix macromolecules using a collagen promoter GFP reporter transgene (pOBCol3.6GFP) as a marker of Col1a1 expression. This analysis of pOBCol3.6GFP expression in Tsk2/+ skin showed an increase in transgene activity compared to wild-type (+/+) samples. In addition, an increased area of "high" GFP fluorescence in Tsk2/+ dermis in both 1- and 4-month-old mice was observed that was also associated with an increased number of dermal fibroblasts per unit area of dermis. These data collectively suggest an important mechanism of Tsk2/+ skin fibrosis; an increased number of collagen expressing cells as well as elevated collagen expression on a per cell basis. During this study it was noted that Tsk2/+ mice appeared consistently smaller than wild-type (+/+) siblings and measurements of body length revealed a decrease (5-10%) in 1- and 2-month-old Tsk2/+ mice as well as a decrease in body weight in both age groups as compared to wild-type (+/+) control mice. Femur length was also decreased (2-9%) in Tsk2/+ mice. Finally, in contrast to Tsk/+ mice that display an emphysema-like lung pathology, histological sections of lungs from Tsk2/+ mice were normal and indistinguishable from wild-type (+/+) controls.
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Affiliation(s)
- Tatjana Barisic-Dujmovic
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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Khosla S. Re: "The 3.6 kb DNA fragment from the rat Col1a1 gene promoter drives the expression of genes in both osteoblast and osteoclast lineage cells" by Boban et al. (Bone 39:1302-1312, 2006). Bone 2007; 40:1671-2; author reply 1673-4. [PMID: 17376754 PMCID: PMC1952213 DOI: 10.1016/j.bone.2007.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2007] [Accepted: 02/12/2007] [Indexed: 11/17/2022]
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43
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Boban I, Barisic-Dujmovic T, Clark SH. Parabiosis and transplantation models show no evidence of circulating dermal fibroblast progenitors in bleomycin-induced skin fibrosis. J Cell Physiol 2007; 214:230-7. [PMID: 17579342 DOI: 10.1002/jcp.21182] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To test the hypothesis of an extra-dermal origin of dermal fibroblasts, parabiosis, and transplantation models were developed utilizing a collagen promoter green fluorescent protein (GFP) reporter transgene expressed in dermal fibroblasts. Parabiotic pairs were treated with bleomycin to induce the skin fibrosis that was evaluated for a dense deposition of collagen and inflammatory cell infiltrates in the thickened dermis in comparison with parabiotic pairs treated with saline. Although, in all cases, repeated injection of bleomycin for 4 weeks induced skin fibrosis, only a few GFP positive cells were detected in skin samples from some of the treated non-transgenic mice. Unexpectedly, similar results were observed in saline treated controls. Furthermore, bone marrow chimeras were created in which non-transgenic recipient mice received injections of bone marrow cell preparations isolated from pOBCol3.6GFP transgenic mice. After bone marrow chimerism had been successfully established, fibrotic lesions in the skin were induced by local bleomycin injections. Donor GFP expressing cells were observed in the skin from all recipient mice. However, no difference in the presence of GFP expressing cells was observed between non-treated mice or mice treated with bleomycin or saline. A large number of GFP expressing cells were observed in the lung preparations from all chimeric mice. Mac-3 antibody immunostaining confirmed a macrophage phenotype for these GFP expressing cells suggesting the expression of the pOBCol3.6GFP transgene in a non-collagen producing cell. Based on these observations, we found no evidence of circulating dermal fibroblast progenitors that participate in the development of bleomycin-induced skin fibrosis.
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Affiliation(s)
- Ivana Boban
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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