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Swiderski K, Chan AS, Herold MJ, Kueh AJ, Chung JD, Hardee JP, Trieu J, Chee A, Naim T, Gregorevic P, Lynch GS. The BALB/c.mdx62 mouse exhibits a dystrophic muscle pathology and is a model of Duchenne muscular dystrophy. Dis Model Mech 2024; 17:dmm050502. [PMID: 38602028 PMCID: PMC11095634 DOI: 10.1242/dmm.050502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating monogenic skeletal muscle-wasting disorder. Although many pharmacological and genetic interventions have been reported in preclinical studies, few have progressed to clinical trials with meaningful benefit. Identifying therapeutic potential can be limited by availability of suitable preclinical mouse models. More rigorous testing across models with varied background strains and mutations can identify treatments for clinical success. Here, we report the generation of a DMD mouse model with a CRISPR-induced deletion within exon 62 of the dystrophin gene (Dmd) and the first generated in BALB/c mice. Analysis of mice at 3, 6 and 12 months of age confirmed loss of expression of the dystrophin protein isoform Dp427 and resultant dystrophic pathology in limb muscles and the diaphragm, with evidence of centrally nucleated fibers, increased inflammatory markers and fibrosis, progressive decline in muscle function, and compromised trabecular bone development. The BALB/c.mdx62 mouse is a novel model of DMD with associated variations in the immune response and muscle phenotype, compared with those of existing models. It represents an important addition to the preclinical model toolbox for developing therapeutic strategies.
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Affiliation(s)
- Kristy Swiderski
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Audrey S. Chan
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Marco J. Herold
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3052, Australia
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC 3084, Australia
- School of Cancer Medicine, La Trobe University, Heidelberg, VIC 3084, Australia
| | - Andrew J. Kueh
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3052, Australia
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC 3084, Australia
- School of Cancer Medicine, La Trobe University, Heidelberg, VIC 3084, Australia
| | - Jin D. Chung
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Justin P. Hardee
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Jennifer Trieu
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Annabel Chee
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Timur Naim
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Paul Gregorevic
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Gordon S. Lynch
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
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Jürimäe J, Remmel L, Tamm AL, Purge P, Maasalu K, Tillmann V. Follistatin Is Associated with Bone Mineral Density in Lean Adolescent Girls with Increased Physical Activity. CHILDREN (BASEL, SWITZERLAND) 2023; 10:1226. [PMID: 37508723 PMCID: PMC10378065 DOI: 10.3390/children10071226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/30/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023]
Abstract
Follistatin is a member of the activin-follistatin-inhibin hormonal system and is proposed to affect bone metabolism. However, data regarding the effect of follistatin on bone are relatively scarce and contradictory in humans. The purpose of the current study was to investigate possible associations of serum follistatin concentration with bone mineral characteristics in lean and physically active adolescent girls. Bone mineral density, body composition, resting energy expenditure and different energy homeostasis hormones in serum including follistatin, leptin and insulin were investigated. Significant relationships (p < 0.05) between serum follistatin (1275.1 ± 263.1 pg/mL) and whole-body (WB) bone mineral content (r = 0.33), WB areal bone mineral density (aBMD) (r = 0.23) and lumbar spine (LS) aBMD (r = 0.29) values were observed. Serum follistatin remained associated with LS aBMD independent of body fat and lean masses (r = 0.21; p < 0.05). However, the follistatin concentration explained only 3% (R2 × 100; p = 0.049) of the total variance in LS aBMD values. In conclusion, serum follistatin concentrations were associated with bone mineral values in lean adolescent girls with increased physical activity. Follistatin was an independent predictor of lumbar spine areal bone mineral density, which predominantly consists of trabecular bone.
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Affiliation(s)
- Jaak Jürimäe
- Institute of Sport Sciences and Physiotherapy, Faculty of Medicine, University of Tartu, 51008 Tartu, Estonia
| | - Liina Remmel
- Institute of Sport Sciences and Physiotherapy, Faculty of Medicine, University of Tartu, 51008 Tartu, Estonia
| | - Anna-Liisa Tamm
- Department of Physiotherapy and Environmental Health, Tartu Health Care College, 50411 Tartu, Estonia
| | - Priit Purge
- Institute of Sport Sciences and Physiotherapy, Faculty of Medicine, University of Tartu, 51008 Tartu, Estonia
| | - Katre Maasalu
- Institute of Clinical Medicine, Faculty of Medicine, University of Tartu, 50406 Tartu, Estonia
| | - Vallo Tillmann
- Institute of Clinical Medicine, Faculty of Medicine, University of Tartu, 50406 Tartu, Estonia
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Gielen E, Dupont J, Dejaeger M, Laurent MR. Sarcopenia, osteoporosis and frailty. Metabolism 2023; 145:155638. [PMID: 37348597 DOI: 10.1016/j.metabol.2023.155638] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/21/2023] [Accepted: 06/17/2023] [Indexed: 06/24/2023]
Abstract
Muscles and bones are intricately connected tissues displaying marked co-variation during development, growth, aging, and in many diseases. While the diagnosis and treatment of osteoporosis are well established in clinical practice, sarcopenia has only been classified internationally as a disease in 2016. Both conditions are associated with an increased risk of adverse health outcomes such as fractures, dysmobility and mortality. Rather than focusing on one dimension of bone or muscle mass or weakness, the concept of musculoskeletal frailty captures the overall loss of physiological reserves in the locomotor system with age. The term osteosarcopenia in particular refers to the double jeopardy of osteoporosis and sarcopenia. Muscle-bone interactions at the biomechanical, cellular, paracrine, endocrine, neuronal or nutritional level may contribute to the pathophysiology of osteosarcopenia. The paradigm wherein muscle force controls bone strength is increasingly facing competition from a model centering on the exchange of myokines, osteokines and adipokines. The most promising results have been obtained in preclinical models where common drug targets have been identified to treat these conditions simultaneously. In this narrative review, we critically summarize the current understanding of the definitions, epidemiology, pathophysiology, and treatment of osteosarcopenia as part of an integrative approach to musculoskeletal frailty.
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Affiliation(s)
- Evelien Gielen
- Gerontology and Geriatrics Unit, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Jolan Dupont
- Gerontology and Geriatrics Unit, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium
| | - Marian Dejaeger
- Gerontology and Geriatrics Unit, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Michaël R Laurent
- Centre for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; Geriatrics Department, Imelda Hospital, Bonheiden, Belgium.
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McGregor NE, Walker EC, Chan AS, Poulton IJ, Cho EHJ, Windahl SH, Sims NA. STAT3 Hyperactivation Due to SOCS3 Deletion in Murine Osteocytes Accentuates Responses to Exercise- and Load-Induced Bone Formation. J Bone Miner Res 2022; 37:547-558. [PMID: 34870348 DOI: 10.1002/jbmr.4484] [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: 08/25/2021] [Revised: 11/07/2021] [Accepted: 11/27/2021] [Indexed: 12/16/2022]
Abstract
Cortical bone develops and changes in response to mechanical load, which is sensed by bone-embedded osteocytes. The bone formation response to load depends on STAT3 intracellular signals, which are upregulated after loading and are subject to negative feedback from Suppressor of Cytokine Signaling 3 (Socs3). Mice with Dmp1Cre-targeted knockout of Socs3 have elevated STAT3 signaling in osteocytes and display delayed cortical bone maturation characterized by impaired accrual of high-density lamellar bone. This study aimed to determine whether these mice exhibit an altered response to mechanical load. The approach used was to test both treadmill running and tibial compression in female Dmp1Cre.Socs3f/f mice. Treadmill running for 5 days per week from 6 to 11 weeks of age did not change cortical bone mass in control mice, but further delayed cortical bone maturation in Dmp1Cre.Socs3f/f mice; accrual of high-density bone was suppressed, and cortical thickness was less than in genetically-matched sedentary controls. When strain-matched anabolic tibial loading was tested, both control and Dmp1Cre.Socs3f/f mice exhibited a significantly greater cortical thickness and periosteal perimeter in loaded tibia compared with the contralateral non-loaded bone. At the site of greatest compressive strain, the loaded Dmp1Cre.Socs3f/f tibias showed a significantly greater response than controls, indicated by a greater increase in cortical thickness. This was due to a greater bone formation response on both periosteal and endocortical surfaces, including formation of abundant woven bone on the periosteum. This suggests a greater sensitivity to mechanical load in Dmp1Cre.Socs3f/f bone. In summary, mice with targeted SOCS3 deletion and immature cortical bone have an exaggerated response to both physiological and experimental mechanical loads. We conclude that there is an optimal level of osteocytic response to mechanical load required for cortical bone maturation and that load-induced bone formation may be increased by augmenting STAT3 signaling within osteocytes. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
| | - Emma C Walker
- St. Vincent's Institute of Medical Research, Fitzroy, Australia
| | - Audrey Sm Chan
- Centre for Muscle Research, The University of Melbourne, Melbourne, Australia
| | | | - Ellie H-J Cho
- Biological Optical Microscopy Platform, The University of Melbourne, Melbourne, Australia
| | - Sara H Windahl
- Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet, Huddinge, Sweden
| | - Natalie A Sims
- St. Vincent's Institute of Medical Research, Fitzroy, Australia.,Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Australia
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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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