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Koh NYY, Miszkiewicz JJ, Fac ML, Wee NKY, Sims NA. Preclinical Rodent Models for Human Bone Disease, Including a Focus on Cortical Bone. Endocr Rev 2024; 45:493-520. [PMID: 38315213 PMCID: PMC11244217 DOI: 10.1210/endrev/bnae004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/22/2023] [Accepted: 02/02/2024] [Indexed: 02/07/2024]
Abstract
Preclinical models (typically ovariectomized rats and genetically altered mice) have underpinned much of what we know about skeletal biology. They have been pivotal for developing therapies for osteoporosis and monogenic skeletal conditions, including osteogenesis imperfecta, achondroplasia, hypophosphatasia, and craniodysplasias. Further therapeutic advances, particularly to improve cortical strength, require improved understanding and more rigorous use and reporting. We describe here how trabecular and cortical bone structure develop, are maintained, and degenerate with aging in mice, rats, and humans, and how cortical bone structure is changed in some preclinical models of endocrine conditions (eg, postmenopausal osteoporosis, chronic kidney disease, hyperparathyroidism, diabetes). We provide examples of preclinical models used to identify and test current therapies for osteoporosis, and discuss common concerns raised when comparing rodent preclinical models to the human skeleton. We focus especially on cortical bone, because it differs between small and larger mammals in its organizational structure. We discuss mechanisms common to mouse and human controlling cortical bone strength and structure, including recent examples revealing genetic contributors to cortical porosity and osteocyte network configurations during growth, maturity, and aging. We conclude with guidelines for clear reporting on mouse models with a goal for better consistency in the use and interpretation of these models.
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Affiliation(s)
- Natalie Y Y Koh
- Bone Cell Biology & Disease Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
- Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Justyna J Miszkiewicz
- School of Social Science, The University of Queensland, Brisbane, QLD 4072, Australia
- Vertebrate Evolution Development and Ecology, Naturalis Biodiversity Center, 2333 CR Leiden, The Netherlands
| | - Mary Louise Fac
- Bone Cell Biology & Disease Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
- Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Natalie K Y Wee
- Bone Cell Biology & Disease Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
- Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Natalie A Sims
- Bone Cell Biology & Disease Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
- Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC 3065, Australia
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Isojima T, Walker EC, Poulton IJ, McGregor NE, Wicks IP, Gooi JH, Martin TJ, Sims NA. G-CSF Receptor Deletion Amplifies Cortical Bone Dysfunction in Mice With STAT3 Hyperactivation in Osteocytes. J Bone Miner Res 2022; 37:1876-1890. [PMID: 35856245 DOI: 10.1002/jbmr.4654] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 06/27/2022] [Accepted: 07/16/2022] [Indexed: 11/09/2022]
Abstract
Bone strength is determined by the structure and composition of its thickened outer shell (cortical bone), yet the mechanisms controlling cortical consolidation are poorly understood. Cortical bone maturation depends on SOCS3-mediated suppression of IL-6 cytokine-induced STAT3 phosphorylation in osteocytes, the cellular network embedded in bone matrix. Because SOCS3 also suppresses granulocyte-colony-stimulating factor receptor (G-CSFR) signaling, we here tested whether global G-CSFR (Csf3r) ablation altereed bone structure in male and female mice lacking SOCS3 in osteocytes, (Dmp1Cre :Socs3f/f mice). Dmp1Cre :Socs3f/f :Csf3r-/- mice were generated by crossing Dmp1Cre :Socs3f/f mice with Csf3r-/- mice. Although G-CSFR is not expressed in osteocytes, Csf3r deletion further delayed cortical consolidation in Dmp1Cre :Socs3f/f mice. Micro-CT images revealed extensive, highly porous low-density bone, with little true cortex in the diaphysis, even at 26 weeks of age; including more low-density bone and less high-density bone in Dmp1Cre :Socs3f/f :Csf3r-/- mice than controls. By histology, the area where cortical bone would normally be found contained immature compressed trabecular bone in Dmp1Cre :Socs3f/f :Csf3r-/- mice and greater than normal levels of intracortical osteoclasts, extensive new woven bone formation, and the presence of more intracortical blood vessels than the already high levels observed in Dmp1Cre :Socs3f/f controls. qRT-PCR of cortical bone from Dmp1Cre :Socs3f/f :Csf3r-/- mice also showed more than a doubling of mRNA levels for osteoclasts, osteoblasts, RANKL, and angiogenesis markers. The further delay in cortical bone maturation was associated with significantly more phospho-STAT1 and phospho-STAT3-positive osteocytes, and a threefold increase in STAT1 and STAT3 target gene mRNA levels, suggesting G-CSFR deletion further increases STAT signaling beyond that of Dmp1Cre :Socs3f/f bone. G-CSFR deficiency therefore promotes STAT1/3 signaling in osteocytes, and when SOCS3 negative feedback is absent, elevated local angiogenesis, bone resorption, and bone formation delays cortical bone consolidation. This points to a critical role of G-CSF in replacing condensed trabecular bone with lamellar bone during cortical bone formation. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Tsuyoshi Isojima
- St. Vincent's Institute of Medical Research, Fitzroy, Australia.,Department of Pediatrics, Teikyo University School of Medicine, Tokyo, Japan
| | - Emma C Walker
- St. Vincent's Institute of Medical Research, Fitzroy, Australia
| | | | | | - Ian P Wicks
- Walter and Eliza Hall Institute, Parkville, Australia
| | - Jonathan H Gooi
- St. Vincent's Institute of Medical Research, Fitzroy, Australia.,Bio21 Molecular Science and Biotechnology Institute, Parkville, Australia
| | - T John Martin
- St. Vincent's Institute of Medical Research, Fitzroy, Australia.,The University of Melbourne, Department of Medicine at St. Vincent's Hospital, Fitzroy, Australia
| | - Natalie A Sims
- St. Vincent's Institute of Medical Research, Fitzroy, Australia.,The University of Melbourne, Department of Medicine at St. Vincent's Hospital, Fitzroy, Australia
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Wee NK, Sims NA, Morello R. The Osteocyte Transcriptome: Discovering Messages Buried Within Bone. Curr Osteoporos Rep 2021; 19:604-615. [PMID: 34757588 PMCID: PMC8720072 DOI: 10.1007/s11914-021-00708-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/24/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE OF THE REVIEW Osteocytes are cells embedded within the bone matrix, but their function and specific patterns of gene expression remain only partially defined; this is beginning to change with recent studies using transcriptomics. This unbiased approach can generate large amounts of data and is now being used to identify novel genes and signalling pathways within osteocytes both at baseline conditions and in response to stimuli. This review outlines the methods used to isolate cell populations containing osteocytes, and key recent transcriptomic studies that used osteocyte-containing preparations from bone tissue. RECENT FINDINGS Three common methods are used to prepare samples to examine osteocyte gene expression: digestion followed by sorting, laser capture microscopy, and the isolation of cortical bone shafts. All these methods present challenges in interpreting the data generated. Genes previously not known to be expressed by osteocytes have been identified and variations in osteocyte gene expression have been reported with age, sex, anatomical location, mechanical loading, and defects in bone strength. A substantial proportion of newly identified transcripts in osteocytes remain functionally undefined but several have been cross-referenced with functional data. Future work and improved methods (e.g. scRNAseq) likely provide useful resources for the study of osteocytes and important new information on the identity and functions of this unique cell type within the skeleton.
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Affiliation(s)
- Natalie Ky Wee
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, 9 Princes St, Fitzroy, 3065, Australia
| | - Natalie A Sims
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, 9 Princes St, Fitzroy, 3065, Australia
- Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, 3065, Australia
| | - Roy Morello
- Department of Physiology & Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
- Department of Orthopaedic Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
- Division of Genetics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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Isojima T, Sims NA. Cortical bone development, maintenance and porosity: genetic alterations in humans and mice influencing chondrocytes, osteoclasts, osteoblasts and osteocytes. Cell Mol Life Sci 2021; 78:5755-5773. [PMID: 34196732 PMCID: PMC11073036 DOI: 10.1007/s00018-021-03884-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/06/2021] [Accepted: 06/21/2021] [Indexed: 12/13/2022]
Abstract
Cortical bone structure is a crucial determinant of bone strength, yet for many years studies of novel genes and cell signalling pathways regulating bone strength have focused on the control of trabecular bone mass. Here we focus on mechanisms responsible for cortical bone development, growth, and degeneration, and describe some recently described genetic-driven modifications in humans and mice that reveal how these processes may be controlled. We start with embryonic osteogenesis of preliminary bone structures preceding the cortex and describe how this structure consolidates then matures to a dense, vascularised cortex containing an increasing proportion of lamellar bone. These processes include modelling-induced, and load-dependent, asymmetric cortical expansion, which enables the cortex's transition from a highly porous woven structure to a consolidated and thickened highly mineralised lamellar bone structure, infiltrated by vascular channels. Sex-specific differences emerge during this process. With aging, the process of consolidation reverses: cortical pores enlarge, leading to greater cortical porosity, trabecularisation and loss of bone strength. Each process requires co-ordination between bone formation, bone mineralisation, vascularisation, and bone resorption, with a need for locational-, spatial- and cell-specific signalling pathways to mediate this co-ordination. We will discuss these processes, and a number of cell-signalling pathways identified in both murine and human genetic studies to regulate cortical bone mass, including signalling through gp130, STAT3, PTHR1, WNT16, NOTCH, NOTUM and sFRP4.
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Affiliation(s)
- Tsuyoshi Isojima
- St. Vincent's Institute of Medical Research, 9 Princes St, Fitzroy, VIC, 3122, Australia
- Department of Pediatrics, Teikyo University School of Medicine, Tokyo, Japan
| | - Natalie A Sims
- St. Vincent's Institute of Medical Research, 9 Princes St, Fitzroy, VIC, 3122, Australia.
- Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC, Australia.
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