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Zhou H, Liu H, Lin M, Wang H, Zhou J, Li M, Yang X, Fu G, Liu C. Hyperbaric oxygen promotes bone regeneration by activating the mechanosensitive Piezo1 pathway in osteogenic progenitors. J Orthop Translat 2024; 48:11-24. [PMID: 39170748 PMCID: PMC11338066 DOI: 10.1016/j.jot.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/17/2024] [Accepted: 07/03/2024] [Indexed: 08/23/2024] Open
Abstract
Background Hyperbaric oxygen (HBO) therapy is widely used to treat bone defects, but the correlation of high oxygen concentration and pressure to osteogenesis is unclear. Methods Bilateral monocortical tibial defect surgeries were performed on 12-week-old Prrx1-Cre; Rosa26-tdTomato and Prrx1-Cre; Piezo1fl/+ mice. Daily HBO treatment was applied on post-surgery day (PSD) 1-9; and daily mechanical loading on tibia was from PSD 5 to 8. The mice were euthanized on PSD 10, and bone defect repair in their tibias was evaluated using μCT, biomechanical testing, and immunofluorescence deep-tissue imaging. The degree of angiogenesis-osteogenesis coupling was determined through spatial correlation analysis. Bone marrow stromal cells from knockout mice were cultured in vitro, and their osteogenic capacities of the cells were assessed. The activation of genes in the Piezo1-YAP pathway was evaluated using RNA sequencing and quantitative real-time polymerase chain reaction. Results Lineage tracing showed HBO therapy considerably altered the number of Prrx1+ cells and their progeny in a healing bone defect. Using conditional knockdown mice, we found that HBO stimulation activates the Piezo1-YAP axis in Prrx1+ cells and promotes osteogenesis-angiogenesis coupling during bone repair. The beneficial effect of HBO was similar to that of anabolic mechanical stimulation, which also acts through the Piezo1-YAP axis. Subsequent transcriptome sequencing results revealed that similar mechanosensitive pathways are activated by HBO therapy in a bone defect. Conclusion HBO therapy promotes bone tissue regeneration through the mechanosensitive Piezo1-YAP pathway in a population of Prrx1+ osteogenic progenitors. Our results contribute to the understanding of the mechanism by which HBO therapy treats bone defects. The Translational Potential of this Article Hyperbaric oxygen therapy is widely used in clinical settings. Our results show that osteogenesis was induced by the activation of the Piezo1-YAP pathway in osteoprogenitors after HBO stimulation, and the underlying mechanism was elucidated. These results may help improve current HBO methods and lead to the formulation of alternative treatments that achieve the same functional outcomes.
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Affiliation(s)
- Hang Zhou
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
| | - Hongzhi Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
| | - Minmin Lin
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
| | - Hantang Wang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
| | - Jingjing Zhou
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
| | - Ming Li
- Department of Rehabilitation Medicine, Shenzhen Children's Hospital, No. 7019 Yitian Road, Futian District, Shenzhen, Guangdong, China
| | - Xue Yang
- Department of Rehabilitation Medicine, Shenzhen Children's Hospital, No. 7019 Yitian Road, Futian District, Shenzhen, Guangdong, China
| | - Guibing Fu
- Department of Pediatric Orthopedics, Shenzhen Children's Hospital, No. 7019 Yitian Road, Futian District, Shenzhen, Guangdong, China
| | - Chao Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Engineering Building south 622, 1088 Xueyuan Avenue, Shenzhen, Guangdong, China
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Liu Y, Wang Y, Lin M, Liu H, Pan Y, Wu J, Guo Z, Li J, Yan B, Zhou H, Fan Y, Hu G, Liang H, Zhang S, Siu MFF, Wu Y, Bai J, Liu C. Cellular Scale Curvature in Bioceramic Scaffolds Enhanced Bone Regeneration by Regulating Skeletal Stem Cells and Vascularization. Adv Healthc Mater 2024:e2401667. [PMID: 38923234 DOI: 10.1002/adhm.202401667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 06/20/2024] [Indexed: 06/28/2024]
Abstract
Critical-sized segmental bone defects cannot heal spontaneously, leading to disability and significant increase in mortality. However, current treatments utilizing bone grafts face a variety of challenges from donor availability to poor osseointegration. Drugs such as growth factors increase cancer risk and are very costly. Here, a porous bioceramic scaffold that promotes bone regeneration via solely mechanobiological design is reported. Two types of scaffolds with high versus low pore curvatures are created using high-precision 3D printing technology to fabricate pore curvatures radius in the 100s of micrometers. While both are able to support bone formation, the high-curvature pores induce higher ectopic bone formation and increased vessel invasion. Scaffolds with high-curvature pores also promote faster regeneration of critical-sized segmental bone defects by activating mechanosensitive pathways. High-curvature pore recruits skeletal stem cells and type H vessels from both the periosteum and the marrow during the early phase of repair. High-curvature pores have increased survival of transplanted GFP-labeled skeletal stem cells (SSCs) and recruit more host SSCs. Taken together, the bioceramic scaffolds with defined micrometer-scale pore curvatures demonstrate a mechanobiological approach for orthopedic scaffold design.
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Affiliation(s)
- Yang Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Yue Wang
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
| | - Minmin Lin
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Hongzhi Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Yonghao Pan
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Jianqun Wu
- College of Medicine, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
| | - Ziyu Guo
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Jiawei Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Bingtong Yan
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Hang Zhou
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Yuanhao Fan
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Ganqing Hu
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, 14850, USA
| | - Haowen Liang
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
| | - Shibo Zhang
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
| | - Ming-Fung Francis Siu
- Department of Building and Real Estate, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Yongbo Wu
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
| | - Jiaming Bai
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
| | - Chao Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Nanshan District, Shenzhen, 518055, P. R. China
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Matsumoto T, Hashimoto K, Okada H. Discretizing low-intensity whole-body vibration into bouts with short rest intervals promotes bone defect repair in osteoporotic mice. J Orthop Res 2024; 42:1267-1275. [PMID: 38234146 DOI: 10.1002/jor.25781] [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: 10/01/2023] [Revised: 12/19/2023] [Accepted: 12/24/2023] [Indexed: 01/19/2024]
Abstract
Continuous administration of low-intensity whole-body vibration (WBV) gradually diminishes bone mechanosensitivity over time, leading to a weakening of its osteogenic effect. We investigated whether discretizing WBV into bouts with short rest intervals was effective in enhancing osteoporotic bone repair. Ten-week-old female mice were ovariectomized and underwent drill-hole defect surgery (Day 0) on the right tibial diaphysis at 11 weeks of age. The mice underwent one of three regimens starting from Day 1 for 5 days/week: continuous WBV at 45 Hz and 0.3 g for 7.5 min/day (cWBV); 3-s bouts of WBV at 45 Hz, 0.3 g followed by 9-s rest intervals, repeated for 30 min/day (repeated bouts of whole-body vibration with short rest intervals [rWBV]); or a sham treatment. Both the cWBV and rWBV groups received a total of 20,250 vibration cycles per day. On either Day 7 or 14 posteuthanasia (n = 6/group/timepoint), the bone and angiogenic vasculature in the defect were computed tomography imaged using synchrotron light. By Day 14, the bone repair was most advanced in the rWBV group, showing a higher bone volume fraction and a more uniform mineral distribution compared with the sham group. The cWBV group exhibited an intermediate level of bone repair between the sham and rWBV groups. The rWBV group had a decrease in large-sized angiogenic vessels, while the cWBV group showed an increase in such vessels. In conclusion, osteoporotic bone repair was enhanced by WBV bouts with short rest intervals, which may potentially be attributed to the improved mechanosensitivity of osteogenic cells and alterations in angiogenic vasculature.
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Affiliation(s)
- Takeshi Matsumoto
- Division of Science and Technology, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
| | - Keishi Hashimoto
- Division of Science and Technology, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
| | - Hyuga Okada
- Division of Science and Technology, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
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Zhu Y, Li Y, Cao Z, Xue J, Wang X, Hu T, Han B, Guo Y. Mechanically strained osteocyte-derived exosomes contained miR-3110-5p and miR-3058-3p and promoted osteoblastic differentiation. Biomed Eng Online 2024; 23:44. [PMID: 38705993 PMCID: PMC11070085 DOI: 10.1186/s12938-024-01237-9] [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: 01/25/2024] [Accepted: 04/11/2024] [Indexed: 05/07/2024] Open
Abstract
BACKGROUND Osteocytes are critical mechanosensory cells in bone, and mechanically stimulated osteocytes produce exosomes that can induce osteogenesis. MicroRNAs (miRNAs) are important constituents of exosomes, and some miRNAs in osteocytes regulate osteogenic differentiation; previous studies have indicated that some differentially expressed miRNAs in mechanically strained osteocytes likely influence osteoblastic differentiation. Therefore, screening and selection of miRNAs that regulate osteogenic differentiation in exosomes of mechanically stimulated osteocytes are important. RESULTS A mechanical tensile strain of 2500 με at 0.5 Hz 1 h per day for 3 days, elevated prostaglandin E2 (PGE2) and insulin-like growth factor-1 (IGF-1) levels and nitric oxide synthase (NOS) activity of MLO-Y4 osteocytes, and promoted osteogenic differentiation of MC3T3-E1 osteoblasts. Fourteen miRNAs differentially expressed only in MLO-Y4 osteocytes which were stimulated with mechanical tensile strain, were screened, and the miRNAs related to osteogenesis were identified. Four differentially expressed miRNAs (miR-1930-3p, miR-3110-5p, miR-3090-3p, and miR-3058-3p) were found only in mechanically strained osteocytes, and the four miRNAs, eight targeted mRNAs which were differentially expressed only in mechanically strained osteoblasts, were also identified. In addition, the mechanically strained osteocyte-derived exosomes promoted the osteoblastic differentiation of MC3T3-E1 cells in vitro, the exosomes were internalized by osteoblasts, and the up-regulated miR-3110-5p and miR-3058-3p in mechanically strained osteocytes, were both increased in the exosomes, which was verified via reverse transcription quantitative polymerase chain reaction (RT-qPCR). CONCLUSIONS In osteocytes, a mechanical tensile strain of 2500 με at 0.5 Hz induced the fourteen differentially expressed miRNAs which probably were in exosomes of osteocytes and involved in osteogenesis. The mechanically strained osteocyte-derived exosomes which contained increased miR-3110-5p and miR-3058-3p (two of the 14 miRNAs), promoted osteoblastic differentiation.
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Affiliation(s)
- Yingwen Zhu
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
- Education Department of Guangxi Zhuang Autonomous Region, Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
| | - Yanan Li
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
| | - Zhen Cao
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
- Education Department of Guangxi Zhuang Autonomous Region, Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
| | - Jindong Xue
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
- Education Department of Guangxi Zhuang Autonomous Region, Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
| | - Xiaoyan Wang
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
| | - Tingting Hu
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China
| | - Biao Han
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China.
- Education Department of Guangxi Zhuang Autonomous Region, Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China.
| | - Yong Guo
- Department of Biomedical Engineering, School of Intelligent Medicine and Biotechnology, Guilin Medical University, No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China.
- Education Department of Guangxi Zhuang Autonomous Region, Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), No. 1 Zhiyuan Road, Lingui District, Guilin, 541199, Guangxi, People's Republic of China.
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Ahmad M, Haffner-Luntzer M, Schoppa A, Najafova Z, Lukic T, Yorgan TA, Amling M, Schinke T, Ignatius A. Mechanical induction of osteoanabolic Wnt1 promotes osteoblast differentiation via Plat. FASEB J 2024; 38:e23489. [PMID: 38407813 DOI: 10.1096/fj.202301424rr] [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: 07/13/2023] [Revised: 01/04/2024] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Physical activity-induced mechanical stimuli play a crucial role in preserving bone mass and structure by promoting bone formation. While the Wnt pathway is pivotal for mediating the osteoblast response to loading, the exact mechanisms are not fully understood. Here, we found that mechanical stimulation induces osteoblastic Wnt1 expression, resulting in an upregulation of key osteogenic marker genes, including Runx2 and Sp7, while Wnt1 knockdown using siRNA prevented these effects. RNAseq analysis identified Plat as a major target through which Wnt1 exerts its osteogenic influence. This was corroborated by Plat depletion using siRNA, confirming its positive role in osteogenic differentiation. Moreover, we demonstrated that mechanical stimulation enhances Plat expression, which, in turn leads to increased expression of osteogenic markers like Runx2 and Sp7. Notably, Plat depletion by siRNA prevented this effect. We have established that Wnt1 regulates Plat expression by activating β-Catenin. Silencing Wnt1 impairs mechanically induced β-Catenin activation, subsequently reducing Plat expression. Furthermore, our findings showed that Wnt1 is essential for osteoblasts to respond to mechanical stimulation and induce Runx2 and Sp7 expression, in part through the Wnt1/β-Catenin/Plat signaling pathway. Additionally, we observed significantly reduced Wnt1 and Plat expression in bones from ovariectomy (OVX)-induced and age-related osteoporotic mouse models compared with non-OVX and young mice, respectively. Overall, our data suggested that Wnt1 and Plat play significant roles in mechanically induced osteogenesis. Their decreased expression in bones from OVX and aged mice highlights their potential involvement in post-menopausal and age-related osteoporosis, respectively.
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Affiliation(s)
- Mubashir Ahmad
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | - Melanie Haffner-Luntzer
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | - Astrid Schoppa
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | | | - Teodora Lukic
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
| | - Timur Alexander Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
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Bi M, Yang K, Yu T, Wu G, Li Q. Cell-based mechanisms and strategies of co-culture system both in vivo and vitro for bone tissue engineering. Biomed Pharmacother 2023; 169:115907. [PMID: 37984308 DOI: 10.1016/j.biopha.2023.115907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 11/22/2023] Open
Abstract
The lack of a functional vascular supply has been identified as a major challenge limiting the clinical introduction of stem cell-based bone tissue engineering (BTE) for the repair of large-volume bone defects (LVBD). Various approaches have been explored to improve the vascular supply in tissue-engineered constructs, and the development of strategies that could effectively induce the establishment of a functional vascular supply has become a major goal of BTE research. One of the state-of-the-art methods is to incorporate both angiogenic and osteogenic cells in co-culture systems. This review clarifies the key concepts involved, summarises the cell types and models used to date, and systematically evaluates their performance. We also discuss the cell-to-cell communication between these two cell types and the strategies explored in BTE constructs with angiogenic and osteogenic cells to optimise their functions. In addition, we outline unresolved issues and remaining obstacles that need to be overcome for further development in this field and eventual successful repair of LVBD.
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Affiliation(s)
- Mengning Bi
- Department of Prosthetic Dentistry, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China; Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology Shanghai, China
| | - Kaiwen Yang
- Department of Prosthetic Dentistry, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China; Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; Shanghai Key Laboratory of Stomatology &Shanghai Research Institute of Stomatology; National Clinical Research Center of Stomatology, Shanghai, China
| | - Tao Yu
- Department of Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Gang Wu
- Department of Oral and Maxillofacial Surgery/Pathology, Amsterdam UMC and Academic Center for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam (VU), Amsterdam Movement Science (AMS), Amsterdam, the Netherlands; Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam (UvA) and Vrije Universiteit Amsterdam (VU), Amsterdam, the Netherlands.
| | - Qiong Li
- Department of Prosthetic Dentistry, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China.
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Kendall JJ, Ledoux C, Marques FC, Boaretti D, Schulte FA, Morgan EF, Müller R. An in silico micro-multiphysics agent-based approach for simulating bone regeneration in a mouse femur defect model. Front Bioeng Biotechnol 2023; 11:1289127. [PMID: 38164405 PMCID: PMC10757951 DOI: 10.3389/fbioe.2023.1289127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024] Open
Abstract
Bone defects represent a challenging clinical problem as they can lead to non-union. In silico models are well suited to study bone regeneration under varying conditions by linking both cellular and systems scales. This paper presents an in silico micro-multiphysics agent-based (micro-MPA) model for bone regeneration following an osteotomy. The model includes vasculature, bone, and immune cells, as well as their interaction with the local environment. The model was calibrated by time-lapsed micro-computed tomography data of femoral osteotomies in C57Bl/6J mice, and the differences between predicted bone volume fractions and the longitudinal in vivo measurements were quantitatively evaluated using root mean square error (RMSE). The model performed well in simulating bone regeneration across the osteotomy gap, with no difference (5.5% RMSE, p = 0.68) between the in silico and in vivo groups for the 5-week healing period - from the inflammatory phase to the remodelling phase - in the volume spanning the osteotomy gap. Overall, the proposed micro-MPA model was able to simulate the influence of the local mechanical environment on bone regeneration, and both this environment and cytokine concentrations were found to be key factors in promoting bone regeneration. Further, the validated model matched clinical observations that larger gap sizes correlate with worse healing outcomes and ultimately simulated non-union. This model could help design and guide future experimental studies in bone repair, by identifying which are the most critical in vivo experiments to perform.
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Affiliation(s)
- Jack J. Kendall
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
- Center for Multiscale and Translational Mechanobiology, Boston University, Boston, MA, United States
| | - Charles Ledoux
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | | | | | | | - Elise F. Morgan
- Center for Multiscale and Translational Mechanobiology, Boston University, Boston, MA, United States
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
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8
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Yao L, Lu J, Zhong L, Wei Y, Gui T, Wang L, Ahn J, Boerckel JD, Rux D, Mundy C, Qin L, Pacifici M. Activin A marks a novel progenitor cell population during fracture healing and reveals a therapeutic strategy. eLife 2023; 12:e89822. [PMID: 38079220 PMCID: PMC10783872 DOI: 10.7554/elife.89822] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 12/08/2023] [Indexed: 12/18/2023] Open
Abstract
Insufficient bone fracture repair represents a major clinical and societal burden and novel strategies are needed to address it. Our data reveal that the transforming growth factor-β superfamily member Activin A became very abundant during mouse and human bone fracture healing but was minimally detectable in intact bones. Single-cell RNA-sequencing revealed that the Activin A-encoding gene Inhba was highly expressed in a unique, highly proliferative progenitor cell (PPC) population with a myofibroblast character that quickly emerged after fracture and represented the center of a developmental trajectory bifurcation producing cartilage and bone cells within callus. Systemic administration of neutralizing Activin A antibody inhibited bone healing. In contrast, a single recombinant Activin A implantation at fracture site in young and aged mice boosted: PPC numbers; phosphorylated SMAD2 signaling levels; and bone repair and mechanical properties in endochondral and intramembranous healing models. Activin A directly stimulated myofibroblastic differentiation, chondrogenesis and osteogenesis in periosteal mesenchymal progenitor culture. Our data identify a distinct population of Activin A-expressing PPCs central to fracture healing and establish Activin A as a potential new therapeutic tool.
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Affiliation(s)
- Lutian Yao
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
- Department of Orthopaedics, The First Hospital of China Medical UniversityShenyangChina
| | - Jiawei Lu
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Leilei Zhong
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Yulong Wei
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Tao Gui
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Luqiang Wang
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Jaimo Ahn
- Department of Orthopaedic Surgery, Michigan Medicine, University of MichiganAnn ArborUnited States
| | - Joel D Boerckel
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Danielle Rux
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Christina Mundy
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Ling Qin
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
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9
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Atria PJ, Castillo AB. Skeletal adaptation to mechanical cues during homeostasis and repair: the niche, cells, and molecular signaling. Front Physiol 2023; 14:1233920. [PMID: 37916223 PMCID: PMC10616261 DOI: 10.3389/fphys.2023.1233920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
Bones constantly change and adapt to physical stress throughout a person's life. Mechanical signals are important regulators of bone remodeling and repair by activating skeletal stem and progenitor cells (SSPCs) to proliferate and differentiate into bone-forming osteoblasts using molecular signaling mechanisms not yet fully understood. SSPCs reside in a dynamic specialized microenvironment called the niche, where external signals integrate to influence cell maintenance, behavior and fate determination. The nature of the niche in bone, including its cellular and extracellular makeup and regulatory molecular signals, is not completely understood. The mechanisms by which the niche, with all of its components and complexity, is modulated by mechanical signals during homeostasis and repair are virtually unknown. This review summarizes the current view of the cells and signals involved in mechanical adaptation of bone during homeostasis and repair, with an emphasis on identifying novel targets for the prevention and treatment of age-related bone loss and hard-to-heal fractures.
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Affiliation(s)
- Pablo J. Atria
- Department of Orthopedic Surgery, New York University Grossman School of Medicine, New York, NY, United States
| | - Alesha B. Castillo
- Department of Orthopedic Surgery, New York University Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, New York University Tandon School of Engineering, New York, NY, United States
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10
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Mi C, Zhang X, Yang C, Wu J, Chen X, Ma C, Wu S, Yang Z, Qiao P, Liu Y, Wu W, Guo Z, Liao J, Zhou J, Guan M, Liang C, Liu C, Jin D. Bone disease imaging through the near-infrared-II window. Nat Commun 2023; 14:6287. [PMID: 37813832 PMCID: PMC10562434 DOI: 10.1038/s41467-023-42001-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023] Open
Abstract
Skeletal disorders are commonly diagnosed by X-ray imaging, but the radiation limits its use. Optical imaging through the near-infrared-II window (NIR-II, 1000-1700 nm) can penetrate deep tissues without radiation risk, but the targeting of contrast agent is non-specific. Here, we report that lanthanide-doped nanocrystals can passively target the bone marrow, which can be effective for over two months. We therefore develop the high-resolution NIR-II imaging method for bone disease diagnosis, including the 3D bone imaging instrumentation to show the intravital bone morphology. We demonstrate the monitoring of 1 mm bone defects with spatial resolution comparable to the X-ray imaging result. Moreover, NIR-II imaging can reveal the early onset inflammation as the synovitis in the early stage of rheumatoid arthritis, comparable to micro computed tomography (μCT) in diagnosis of osteoarthritis, including the symptoms of osteophyte and hyperostosis in the knee joint.
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Affiliation(s)
- Chao Mi
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China.
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
- National Institute of Extremely-Weak Magnetic Field Infrastructure, Hangzhou, China.
- Shenzhen Light Life Technology Co., Ltd., Shenzhen, China.
| | - Xun Zhang
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Chengyu Yang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Jianqun Wu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Xinxin Chen
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Chenguang Ma
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Sitong Wu
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Zhichao Yang
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Pengzhen Qiao
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Yang Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Weijie Wu
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Zhiyong Guo
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- National Institute of Extremely-Weak Magnetic Field Infrastructure, Hangzhou, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
| | - Jiayan Liao
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Jiajia Zhou
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Ming Guan
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Shenzhen Light Life Technology Co., Ltd., Shenzhen, China
| | - Chao Liang
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
| | - Chao Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China.
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China.
| | - Dayong Jin
- UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China.
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
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11
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Buettmann EG, DeNapoli RC, Abraham LB, Denisco JA, Lorenz MR, Friedman MA, Donahue HJ. Reambulation following hindlimb unloading attenuates disuse-induced changes in murine fracture healing. Bone 2023; 172:116748. [PMID: 37001629 DOI: 10.1016/j.bone.2023.116748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/18/2023] [Accepted: 03/21/2023] [Indexed: 03/31/2023]
Abstract
Patients with bone and muscle loss from prolonged disuse have higher risk of falls and subsequent fragility fractures. In addition, fracture patients with continued disuse and/or delayed physical rehabilitation have worse clinical outcomes compared to individuals with immediate weight-bearing activity following diaphyseal fracture. However, the effects of prior disuse followed by physical reambulation on fracture healing cellular processes and adjacent bone and skeletal muscle recovery post-injury remains poorly defined. To bridge this knowledge gap and inform future treatment and rehabilitation strategies for fractures, a preclinical model of fracture healing with a history of prior unloading with and without reambulation was employed. First, skeletally mature male and female C57BL/6J mice (18 weeks) underwent hindlimb unloading by tail suspension (HLU) for 3 weeks to induce significant bone and muscle loss modeling enhanced bone fragility. Next, mice had their right femur fractured by open surgical dissection (stabilized with 24-gauge pin). The, mice were randomly assigned to continued HLU or allowed normal weight-bearing reambulation (HLU + R). Mice given normal cage activity throughout the experiment served as healthy age-matched controls. All mice were sacrificed 4-days (DPF4) or 14-days (DPF14) following fracture to assess healing and uninjured hindlimb musculoskeletal properties (6-10 mice per treatment/biological sex). We found that continued disuse following fracture lead to severely diminished uninjured hindlimb skeletal muscle mass (gastrocnemius and soleus) and femoral bone volume adjacent to the fracture site compared to healthy age-matched controls across mouse sexes. Furthermore, HLU led to significantly decreased periosteal expansion (DPF4) and osteochondral tissue formation by DPF14, and trends in increased osteoclastogenesis (DPF14) and decreased woven bone vascular area (DPF14). In contrast, immediate reambulation for 2 weeks after fracture, even following a period of prolonged disuse, was able to increase hindlimb skeletal tissue mass and increase osteochondral tissue formation, albeit not to healthy control levels, in both mouse sexes. Furthermore, reambulation attenuated osteoclast formation seen in woven bone tissue undergoing disuse. Our results suggest that weight-bearing skeletal loading in both sexes immediately following fracture may improve callus healing and prevent further fall risk by stimulating skeletal muscle anabolism and decreasing callus resorption compared to minimal or delayed rehabilitation regimens.
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Affiliation(s)
- Evan G Buettmann
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America
| | - Rachel C DeNapoli
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America
| | - Lovell B Abraham
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America
| | - Joe A Denisco
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America
| | - Madelyn R Lorenz
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America
| | - Michael A Friedman
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America
| | - Henry J Donahue
- Virginia Commonwealth University, Biomedical Engineering, Richmond, VA, United States of America.
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12
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Chen Q, Wang Z, Yang C, Li B, Ren X, Liu C, Xi L. High resolution intravital photoacoustic microscopy reveals VEGF-induced bone regeneration in mouse tibia. Bone 2023; 167:116631. [PMID: 36435450 DOI: 10.1016/j.bone.2022.116631] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022]
Abstract
Osteogenesis and angiogenesis are essential for bone homeostasis and repair. Newly formed vessels convey osteogenic progenitors during bone regeneration. However, the lack of continuous and label-free visualization of the bone microvasculature has resulted in little understanding of the neovascular dynamics. Here, we take advantage of optical-resolution photoacoustic microscopy (ORPAM) for label-free, intravital, long-term observation of the bone vascular dynamics, including angiogenesis, remodeling and quantified angiogenic effect of locally-applied vascular endothelial growth factor (VEGF) in the murine tibial defect model. We employed ex vivo confocal microscopy and micro-computed tomography (micro-CT) imaging to verify the positive role of VEGF treatment. VEGF treatment increased the concentration of total hemoglobin, vascular branching, and vascular density, which correlated with more osteoprogenitors and increased bone formation within the defect. These data demonstrated ORPAM as a useful imaging tool that detected functional capillaries to understand hemodynamics, and revealed the effectiveness of locally delivered therapeutic agents with sufficient sensitivity, contributing to the understanding of spatiotemporal regulatory mechanisms on blood vessels during bone regeneration.
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Affiliation(s)
- Qian Chen
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Ziyan Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chengyu Yang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Baochen Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xingxing Ren
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chao Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
| | - Lei Xi
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Shenzhen Bay Laboratory, Shenzhen, Guangdong 518132, China.
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13
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Gao L, Chen W, Li L, Li J, Kongling W, Zhang Y, Yang X, Zhao Y, Bai J, Wang F. Targeting soluble epoxide hydrolase promotes osteogenic-angiogenic coupling via activating SLIT3/HIF-1α signalling pathway. Cell Prolif 2023:e13403. [PMID: 36636821 DOI: 10.1111/cpr.13403] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 01/14/2023] Open
Abstract
Type H vessels have recently been identified to modulate osteogenesis. Epoxyeicostrioleic acids (EETs) have an essential contribution to vascular homeostasis. However, whether increased EETs with soluble epoxide hydrolase (sEH) inhibitor TPPU enhance the coupling of angiogenesis and osteogenesis remains largely unknown. The effects of TPPU on cross-talk between co-cultured human umbilical vein endothelial cells (HUVECs) and human dental pulp stem cells (hDPSCs), and on long bone growth and calvarial defect repair in mice were investigated in vitro and in vivo. TPPU enhanced osteogenic differentiation of co-cultured HUVECs and hDPSCs in vitro and increased type H vessels, and long bone growth and bone repair of calvarial defect. Mechanistically, TPPU promoted cell proliferation and angiogenesis, reclined cell apoptosis, and significantly increased CD31hi EMCNhi endothelial cells (ECs) and SLIT3 and HIF-1α expression levels in co-cultured HUVECs and hDPSCs. Knockdown of Slit3 in hDPSCs or Hif-1α in HUVECs impaired the formation of CD31hi EMCNhi ECs and reversed TPPU-induced osteogenesis. We defined a previously unidentified effect of TPPU coupling angiogenesis and osteogenesis. TPPU induced type H vessels by upregulating the expression of hDPSCs-derived SLIT3, which resulted in the activation of ROBO1/YAP1/HIF-1α signalling pathway in ECs. Targeting metabolic pathways of EETs represents a new strategy to couple osteogenesis and angiogenesis, sEH is a promising therapeutic target for bone regeneration and repair.
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Affiliation(s)
- Lu Gao
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China.,The Affiliated Stomatological Hospital of Dalian Medical University School of Stomatology, Dalian, China
| | - Weixian Chen
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Lijun Li
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Juanjuan Li
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Wenyao Kongling
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Yaoyang Zhang
- School of Stomatology, Dalian Medical University, Dalian, China.,The Affiliated Stomatological Hospital of Dalian Medical University School of Stomatology, Dalian, China
| | - Xueping Yang
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Yanrong Zhao
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Jie Bai
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China
| | - Fu Wang
- School of Stomatology, Dalian Medical University, Dalian, China.,Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Dalian, China.,The Affiliated Stomatological Hospital of Dalian Medical University School of Stomatology, Dalian, China
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14
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Functional Heterogeneity of Bone Marrow Mesenchymal Stem Cell Subpopulations in Physiology and Pathology. Int J Mol Sci 2022; 23:ijms231911928. [PMID: 36233230 PMCID: PMC9570000 DOI: 10.3390/ijms231911928] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/16/2022] Open
Abstract
Bone marrow mesenchymal stem cells (BMSCs) are multi-potent cell populations and are capable of maintaining bone and body homeostasis. The stemness and potential therapeutic effect of BMSCs have been explored extensively in recent years. However, diverse cell surface antigens and complex gene expression of BMSCs have indicated that BMSCs represent heterogeneous populations, and the natural characteristics of BMSCs make it difficult to identify the specific subpopulations in pathological processes which are often obscured by bulk analysis of the total BMSCs. Meanwhile, the therapeutic effect of total BMSCs is often less effective partly due to their heterogeneity. Therefore, understanding the functional heterogeneity of the BMSC subpopulations under different physiological and pathological conditions could have major ramifications for global health. Here, we summarize the recent progress of functional heterogeneity of BMSC subpopulations in physiology and pathology. Targeting tissue-resident single BMSC subpopulation offers a potentially innovative therapeutic strategy and improves BMSC effectiveness in clinical application.
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15
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Yang C, Liu Y, Wang Z, Lin M, Liu C. Controlled mechanical loading improves bone regeneration by regulating type H vessels in a S1Pr1-dependent manner. FASEB J 2022; 36:e22530. [PMID: 36063128 DOI: 10.1096/fj.202200339rrr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/04/2022] [Accepted: 08/22/2022] [Indexed: 11/11/2022]
Abstract
Despite the best treatment, approximately 10% of fractures still face undesirable repair and result in delayed unions or non-unions. Dynamic mechanical stimulation promotes bone formation, when applied at the correct time frame, with optimal loading magnitude, frequency, and repetition. Controlled mechanical loading significantly increases osteogenic cells during the matrix deposition phase of bone repair. In the bone defect, the blood vessel network guides the initial bone formation activities. A unique blood vessel subtype (Type H) exists in bone, which expresses high levels of CD31 and endomucin, and functions to couple angiogenesis and osteogenesis. However, how this form of controlled mechanical loading regulates the Type H vessels and promotes bone formation is still not clear. Sphingosine 1-phosphate (S1P) participates in the bone anabolic process and is a key regulator of the blood vessel. Its receptor, sphingosine 1-phosphate receptor 1 (S1Pr1), is a mechanosensitive protein that regulates vascular integrity. Therefore, we hypothesis that controlled anabolic mechanical loading promotes bone repair by acting on Type H vessels. To study the effect of S1Pr1 on loading induced-bone repair, we utilized a stabilized tibial defect model, which allows for the application of anabolic mechanical loading. Mechanical loading upregulated S1Pr1 within the entire defect, with up to 80% expressed in blood vessels, as observed by deep tissue imaging. Additionally, S1Pr1 antagonism by W146 inhibited the anabolic effects of mechanical loading. We showed that mechanical loading or activating S1Pr1 could induce YAP nuclear translocation, a key regulator in the cell's mechanical response, in endothelial cells (ECs) in vitro. Inhibition of S1Pr1 in endothelial cells by siRNA reduced loading-induced YAP nuclear translocation and expressions of angiogenic genes. In vivo, YAP nuclear translocation in Type H vessels was up-regulated after mechanical loading but was inhibited by antagonizing S1Pr1. S1Pr1 agonist, FTY720, increased bone volume and Type H vessel volume, similar to that of mechanical stimulation. In conclusion, controlled anabolic mechanical loading enhanced bone formation mainly through Type H vessels in a S1Pr1-dependent manner.
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Affiliation(s)
- Chengyu Yang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
| | - Yang Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
| | - Ziyan Wang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
| | - Minmin Lin
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
| | - Chao Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
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16
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Yang C, Li Z, Liu Y, Hou R, Lin M, Fu L, Wu D, Liu Q, Li K, Liu C. Single-cell spatiotemporal analysis reveals cell fates and functions of transplanted mesenchymal stromal cells during bone repair. Stem Cell Reports 2022; 17:2318-2333. [PMID: 36150383 PMCID: PMC9561611 DOI: 10.1016/j.stemcr.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/15/2022] Open
Abstract
Mesenchymal stromal cells (MSCs) transplantation could enhance bone repair. However, the cell fate of transplanted MSCs, in terms of their local distribution and spatial associations with other types of cells were poorly understood. Here, we developed a single-cell 3D spatial correlation (sc3DSC) method to track transplanted MSCs based on deep tissue microscopy of fluorescent nanoparticles (fNPs) and immunofluorescence of key proteins. Locally delivered fNP-labeled MSCs enhanced tibial defect repair, increased the number of stem cells and vascular maturity in mice. fNP-MSCs persisted in the defect throughout repair. But only a small portion of transplanted cells underwent osteogenic differentiation (OSX+); a significant portion has maintained their expression of mesenchymal stem cell and skeletal stem cell markers (SCA-1 and PRRX1). Our results contribute to the optimization of MSC-based therapies. The sc3DSC method may be useful in studying cell-based therapies for the regeneration of other tissue types or disease models. Transplanted marrow stromal cells associated with vessels during bone defect repair Small proportion of transplanted cells differentiated into osteogenic cells A proportion of transplanted cells maintained expressions of stem cell markers
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Affiliation(s)
- Chengyu Yang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zeshun Li
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yang Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Runpeng Hou
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Minmin Lin
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Linhao Fu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Decheng Wu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Quanying Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kai Li
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Chao Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China.
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17
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Zhang J, Tong Y, Liu Y, Lin M, Xiao Y, Liu C. Mechanical loading attenuated negative effects of nucleotide analogue reverse-transcriptase inhibitor TDF on bone repair via Wnt/β-catenin pathway. Bone 2022; 161:116449. [PMID: 35605959 DOI: 10.1016/j.bone.2022.116449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 12/19/2022]
Abstract
The nucleotide analog reverse-transcriptase inhibitor, tenofovir disoproxil fumarate (TDF), is widely used to treat hepatitis B virus (HBV) and human immunodeficiency virus infection (HIV). However, long-term TDF usage is associated with an increased incidence of bone loss, osteoporosis, fractures, and other adverse reactions. We investigated the effect of chronic TDF use on bone homeostasis and defect repair in mice. In vitro, TDF inhibited osteogenic differentiation and mineralization in MC3T3-E1 cells. In vivo, 8-week-old C57BL/6 female mice were treated with TDF for 38 days to simulate chronic medication. Four-point bending test and μCT showed reduced bone biomechanical properties and microarchitecture in long bones. To investigate the effects of TDF on bone defect repair, we utilized a bilateral tibial monocortical defect model. μCT showed that TDF reduced new bone mineral tissue and bone mineral density (BMD) in the defect. To verify whether mechanical stimulation may be a useful treatment to counteract the negative bone effects of TDF, controlled dynamic mechanical loading was applied to the whole tibia during the matrix deposition phase on post-surgery days (PSDs) 5 to 8. Second harmonic generation (SHG) of collagen fibers and μCT showed that the reduction of new bone volume and bone mineral density caused by TDF was reversed by mechanical loading in the defect. Immunofluorescent deep tissue imaging showed that chronic TDF treatment reduced the number of osteogenic cells and the volume of new vessels. In addition, chronic TDF treatment inhibited the expressions of periostin and β-catenin, but increased the expression of sclerostin. Both negative effects were reversed by mechanical loading. Our study provides strong evidence that chronic use of TDF exerts direct and inhibitory impacts on bone repair, but appropriate mechanical loading could reverse these adverse effects.
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Affiliation(s)
- Jianing Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Yanrong Tong
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Yang Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Minmin Lin
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Yao Xiao
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Chao Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
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18
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Liu Y, Yang Q, Wang Y, Lin M, Tong Y, Huang H, Yang C, Wu J, Tang B, Bai J, Liu C. Metallic Scaffold with Micron-Scale Geometrical Cues Promotes Osteogenesis and Angiogenesis via the ROCK/Myosin/YAP Pathway. ACS Biomater Sci Eng 2022; 8:3498-3514. [PMID: 35834297 DOI: 10.1021/acsbiomaterials.2c00225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The advent of precision manufacturing has enabled the creation of pores in metallic scaffolds with feature size in the range of single microns. In orthopedic implants, pore geometries at the micron scale could regulate bone formation by stimulating osteogenic differentiation and the coupling of osteogenesis and angiogenesis. However, the biological response to pore geometry at the cellular level is not clear. As cells are sensitive to curvature of the pore boundary, this study aimed to investigate osteogenesis in high- vs low-curvature environments by utilizing computer numerical control laser cutting to generate triangular and circular precision manufactured micropores (PMpores). We fabricated PMpores on 100 μm-thick stainless-steel discs. Triangular PMpores had a 30° vertex angle and a 300 μm base, and circular PMpores had a 300 μm diameter. We found triangular PMpores significantly enhanced the elastic modulus, proliferation, migration, and osteogenic differentiation of MC3T3-E1 preosteoblasts through Yes-associated protein (YAP) nuclear translocation. Inhibition of Rho-associated kinase (ROCK) and Myosin II abolished YAP translocation in all pore types and controls. Inhibition of YAP transcriptional activity reduced the proliferation, pore closure, collagen secretion, alkaline phosphatase (ALP), and Alizarin Red staining in MC3T3-E1 cultures. In C166 vascular endothelial cells, PMpores increased the VEGFA mRNA expression even without an angiogenic differentiation medium and induced tubule formation and maintenance. In terms of osteogenesis-angiogenesis coupling, a conditioned medium from MC3T3-E1 cells in PMpores promoted the expression of angiogenic genes in C166 cells. A coculture with MC3T3-E1 induced tubule formation and maintenance in C166 cells and tubule alignment along the edges of pores. Together, curvature cues in micropores are important stimuli to regulate osteogenic differentiation and osteogenesis-angiogenesis coupling. This study uncovered key mechanotransduction signaling components activated by curvature differences in a metallic scaffold and contributed to the understanding of the interaction between orthopedic implants and cells.
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Affiliation(s)
- Yang Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Qihao Yang
- The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Liwan District, 510150 Guangzhou, China
| | - Yue Wang
- Department of Mechanical and Energy Engineering, College of Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Minmin Lin
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Yanrong Tong
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Hanwei Huang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Chengyu Yang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Jianqun Wu
- College of Medicine, Southern University of Science and Technology, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Bin Tang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Jiaming Bai
- Department of Mechanical and Energy Engineering, College of Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - Chao Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Advanced Biomaterials, 1088 Xueyuan Avenue, 518055 Shenzhen, China
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19
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Abstract
Fracture healing is a complex, multistep process that is highly sensitive to mechanical signaling. To optimize repair, surgeons prescribe immediate weight-bearing as-tolerated within 24 hours after surgical fixation; however, this recommendation is based on anecdotal evidence and assessment of bulk healing outcomes (e.g., callus size, bone volume, etc.). Given challenges in accurately characterizing the mechanical environment and the ever-changing properties of the regenerate, the principles governing mechanical regulation of repair, including their cell and molecular basis, are not yet well defined. However, the use of mechanobiological rodent models, and their relatively large genetic toolbox, combined with recent advances in imaging approaches and single-cell analyses is improving our understanding of the bone microenvironment in response to loading. This review describes the identification and characterization of distinct cell populations involved in bone healing and highlights the most recent findings on mechanical regulation of bone homeostasis and repair with an emphasis on osteo-angio coupling. A discussion on aging and its impact on bone mechanoresponsiveness emphasizes the need for novel mechanotherapeutics that can re-sensitize skeletal stem and progenitor cells to physical rehabilitation protocols.
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Affiliation(s)
- Tareq Anani
- Department of Orthopedic Surgery, New York University Langone Health, New York, NY 10010, USA
| | - Alesha B Castillo
- Department of Orthopedic Surgery, New York University Langone Health, New York, NY 10010, USA; Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 11201, USA; Department of Veterans Affairs, New York Harbor Healthcare System, Manhattan Campus, New York, NY 10010, USA.
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20
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Wang Z, Liu Y, Zhang J, Lin M, Xiao C, Bai H, Liu C. Mechanical loading alleviated the inhibition of β2-adrenergic receptor agonist terbutaline on bone regeneration. FASEB J 2021; 35:e22033. [PMID: 34739146 DOI: 10.1096/fj.202101045rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022]
Abstract
The long-term use of adrenergic medication in treating various conditions, such as asthma, increases the chances of bone fracture. Dynamic mechanical loading at a specific time is a method for improving bone quality and promoting healing. Therefore, we hypothesized that precisely controlling the mechanical environment can contribute to the alleviation of the negative effects of chronic treatment with the common asthma drug terbutaline, which is a β2-adrenergic receptor agonist that facilitates bone homeostasis and defect repair through its anabolic effect on osteogenic cells. Our in vitro results showed that terbutaline can directly inhibit osteogenesis by impairing osteogenic differentiation and mineralization. Chronic treatment in vivo was simulated by administering terbutaline to C57BL/6J mice for 4 weeks before bone defect surgery and mechanical loading. We utilized a stabilized tibial defect model, which allowed the application of anabolic mechanical loading. During homeostasis, chronic terbutaline treatment reduced the bone formation rate, the fracture toughness of long bones, and the concentrations of bone formation markers in the sera. During defect repair, terbutaline decreased the bone volume, type H vessel, and total blood vessel volume. Terbutaline treatment reduced the number of osteogenic cells. Periostin, which was secreted mainly by Prrx1+ osteoprogenitors and F4/80+ macrophages, was inhibited by treating the bone defect with terbutaline. Interestingly, controlled mechanical loading facilitated the recovery of bone volume and periostin expression and the number of osteogenic cells within the defect. In conclusion, mechanical loading can rescue negative effects on new bone accrual and repair induced by chronic terbutaline treatment.
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Affiliation(s)
- Ziyan Wang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Yang Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Jianing Zhang
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Minmin Lin
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Chufan Xiao
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Haoying Bai
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Chao Liu
- Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, China
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21
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Taguchi T, Lopez MJ. An overview of de novo bone generation in animal models. J Orthop Res 2021; 39:7-21. [PMID: 32910496 PMCID: PMC7820991 DOI: 10.1002/jor.24852] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 08/27/2020] [Accepted: 09/02/2020] [Indexed: 02/04/2023]
Abstract
Some of the earliest success in de novo tissue generation was in bone tissue, and advances, facilitated by the use of endogenous and exogenous progenitor cells, continue unabated. The concept of one health promotes shared discoveries among medical disciplines to overcome health challenges that afflict numerous species. Carefully selected animal models are vital to development and translation of targeted therapies that improve the health and well-being of humans and animals alike. While inherent differences among species limit direct translation of scientific knowledge between them, rapid progress in ex vivo and in vivo de novo tissue generation is propelling revolutionary innovation to reality among all musculoskeletal specialties. This review contains a comparison of bone deposition among species and descriptions of animal models of bone restoration designed to replicate a multitude of bone injuries and pathology, including impaired osteogenic capacity.
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Affiliation(s)
- Takashi Taguchi
- Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary MedicineLouisiana State UniversityBaton RougeLouisianaUSA
| | - Mandi J. Lopez
- Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary MedicineLouisiana State UniversityBaton RougeLouisianaUSA
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22
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Riffault M, Johnson GP, Owen MM, Javaheri B, Pitsillides AA, Hoey DA. Loss of Adenylyl Cyclase 6 in Leptin Receptor-Expressing Stromal Cells Attenuates Loading-Induced Endosteal Bone Formation. JBMR Plus 2020; 4:e10408. [PMID: 33210061 PMCID: PMC7657397 DOI: 10.1002/jbm4.10408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023] Open
Abstract
Bone marrow stromal/stem cells represent a quiescent cell population that replenish the osteoblast bone‐forming cell pool with age and in response to injury, maintaining bone mass and repair. A potent mediator of stromal/stem cell differentiation in vitro and bone formation in vivo is physical loading, yet it still remains unclear whether loading‐induced bone formation requires the osteogenic differentiation of these resident stromal/stem cells. Therefore, in this study, we utilized the leptin receptor (LepR) to identify and trace the contribution of bone marrow stromal cells to mechanoadaptation of bone in vivo. Twelve‐week‐old Lepr‐cre;tdTomato mice were subjected to compressive tibia loading with an 11 N peak load for 40 cycles, every other day for 2 weeks. Histological analysis revealed that Lepr‐cre;tdTomato+ cells arise perinatally around blood vessels and populate bone surfaces as lining cells or osteoblasts before a percentage undergo osteocytogenesis. Lepr‐cre;tdTomato+ stromal cells within the marrow increase in abundance with age, but not following the application of tibial compressive loading. Mechanical loading induces an increase in bone mass and bone formation parameters, yet does not evoke an increase in Lepr‐cre;tdTomato+ osteoblasts or osteocytes. To investigate whether adenylyl cyclase‐6 (AC6) in LepR cells contributes to this mechanoadaptive response, Lepr‐cre;tdTomato mice were further crossed with AC6fl/fl mice to generate a LepR+ cell‐specific knockout of AC6. These Lepr‐cre;tdTomato;AC6fl/fl animals have an attenuated response to compressive tibia loading, characterized by a deficient load‐induced osteogenic response on the endosteal bone surface. This, therefore, shows that Lepr‐cre;tdTomato+ cells contribute to short‐term bone mechanoadaptation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Mathieu Riffault
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland
| | - Gillian P Johnson
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering University of Limerick Limerick Ireland
| | - Madeline M Owen
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland
| | - Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences The Royal Veterinary College London United Kingdom
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences The Royal Veterinary College London United Kingdom
| | - David A Hoey
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering University of Limerick Limerick Ireland
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23
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Esposito A, Wang L, Li T, Miranda M, Spagnoli A. Role of Prx1-expressing skeletal cells and Prx1-expression in fracture repair. Bone 2020; 139:115521. [PMID: 32629173 PMCID: PMC7484205 DOI: 10.1016/j.bone.2020.115521] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 12/22/2022]
Abstract
The healing capacity of bones after fracture implies the existence of adult regenerative cells. However, information on identification and functional role of fracture-induced progenitors is still lacking. Paired-related homeobox 1 (Prx1) is expressed during skeletogenesis. We hypothesize that fracture recapitulates Prx1's expression, and Prx1 expressing cells are critical to induce repair. To address our hypothesis, we used a combination of in vivo and in vitro approaches, short and long-term cell tracking analyses of progenies and actively expressing cells, cell ablation studies, and rodent animal models for normal and defective fracture healing. We found that fracture elicits a periosteal and endosteal response of perivascular Prx1+ cells that participate in fracture healing and showed that Prx1-expressing cells have a functional role in the repair process. While Prx1-derived cells contribute to the callus, Prx1's expression decreases concurrently with differentiation into cartilaginous and bone cells, similarly to when Prx1+ cells are cultured in differentiating conditions. We determined that bone morphogenic protein 2 (BMP2), through C-X-C motif-ligand-12 (CXCL12) signaling, modulates the downregulation of Prx1. We demonstrated that fracture elicits an early increase in BMP2 expression, followed by a decrease in CXCL12 that in turn down-regulates Prx1, allowing cells to commit to osteochondrogenesis. In vivo and in vitro treatment with CXCR4 antagonist AMD3100 restored Prx1 expression by modulating the BMP2-CXCL12 axis. Our studies represent a shift in the current research that has primarily focused on the identification of markers for postnatal skeletal progenitors, and instead we characterized the function of a specific population (Prx1+ cells) and their expression marker (Prx1) as a crossroad in fracture repair. The identification of fracture-induced perivascular Prx1+ cells and regulation of Prx1's expression by BMP2 and in turn by CXCL12 in the orchestration of fracture repair, highlights a pathway in which to investigate defective mechanisms and therapeutic targets for fracture non-union.
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Affiliation(s)
- Alessandra Esposito
- Department of Orthopaedic Surgery, Section of Molecular Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Lai Wang
- Department of Internal Medicine, Division of Rheumatology, Rush University Medical Center, Chicago, IL, USA
| | - Tieshi Li
- Department of Pediatrics, University of Nebraska Medical Center, Children's Hospital & Medical Center, Omaha, NE, USA
| | - Mariana Miranda
- Department of Orthopaedic Surgery, Section of Molecular Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Anna Spagnoli
- Department of Orthopaedic Surgery, Section of Molecular Medicine, Rush University Medical Center, Chicago, IL, USA; Department of Pediatrics, Division of Pediatric Endocrinology, Rush University Medical Center, Chicago, IL, USA.
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24
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Khajuria DK, Soliman M, Elfar JC, Lewis GS, Abraham T, Kamal F, Elbarbary RA. Aberrant structure of fibrillar collagen and elevated levels of advanced glycation end products typify delayed fracture healing in the diet-induced obesity mouse model. Bone 2020; 137:115436. [PMID: 32439570 PMCID: PMC7938873 DOI: 10.1016/j.bone.2020.115436] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/17/2020] [Accepted: 05/14/2020] [Indexed: 12/16/2022]
Abstract
Impaired fracture healing in patients with obesity-associated type 2 diabetes (T2D) is a significant unmet clinical problem that affects millions of people worldwide. However, the underlying causes are poorly understood. Additionally, limited clinical information is available on how pre-diabetic hyperglycemia in obese individuals impacts bone healing. Here, we use the diet-induced obesity (DIO) mouse (C57BL/6J) model to study the impact of obesity-associated pre-diabetic hyperglycemia on bone healing and fibrillar collagen organization as healing proceeds from one phase to another. We show that DIO mice exhibit defective healing characterized by reduced bone mineral density, bone volume, and bone volume density. Differences in the healing pattern between lean and DIO mice occur early in the healing process as evidenced by faster resorption of the fibrocartilaginous callus in DIO mice. However, the major differences between lean and DIO mice occur during the later phases of endochondral ossification and bone remodeling. Comprehensive analyses of fibrillar collagen microstructure and expression pattern during these phases, using a set of complementary techniques that include histomorphometry, immunofluorescence staining, and second harmonic generation microscopy, demonstrate significant defects in DIO mice. Defects include strikingly sparse and disorganized collagen fibers, as well as pathological accumulation of unfolded collagen triple helices. We also demonstrate that DIO-associated changes in fibrillar collagen structure are attributable, at least in part, to the accumulation of advanced glycation end products, which increase the collagen-fiber crosslink density. These major changes impair fibrillar collagens functions, culminating in defective callus mineralization, remodeling, and strength. Our data extend the understanding of mechanisms by which obesity and its associated hyperglycemia impair fracture healing and underline defective fibrillar collagen microstructure as a novel and important contributor.
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Affiliation(s)
- Deepak Kumar Khajuria
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for Orthopaedic Research and Translational Science (CORTS), The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Marwa Soliman
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for Orthopaedic Research and Translational Science (CORTS), The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - John C Elfar
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for Orthopaedic Research and Translational Science (CORTS), The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Gregory S Lewis
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for Orthopaedic Research and Translational Science (CORTS), The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Thomas Abraham
- Microscopy Imaging Facility, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Neural and Behavioural Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Fadia Kamal
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for Orthopaedic Research and Translational Science (CORTS), The Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Reyad A Elbarbary
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for Orthopaedic Research and Translational Science (CORTS), The Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA.
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25
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Parmentier L, Riffault M, Hoey DA. Utilizing Osteocyte Derived Factors to Enhance Cell Viability and Osteogenic Matrix Deposition within IPN Hydrogels. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E1690. [PMID: 32260406 PMCID: PMC7178658 DOI: 10.3390/ma13071690] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022]
Abstract
Many bone defects arising due to traumatic injury, disease, or surgery are unable to regenerate, requiring intervention. More than four million graft procedures are performed each year to treat these defects making bone the second most commonly transplanted tissue worldwide. However, these types of graft suffer from a limited supply, a second surgical site, donor site morbidity, and pain. Due to the unmet clinical need for new materials to promote skeletal repair, this study aimed to produce novel biomimetic materials to enhance stem/stromal cell osteogenesis and bone repair by recapitulating aspects of the biophysical and biochemical cues found within the bone microenvironment. Utilizing a collagen type I-alginate interpenetrating polymer network we fabricated a material which mirrors the mechanical and structural properties of unmineralized bone, consisting of a porous fibrous matrix with a young's modulus of 64 kPa, both of which have been shown to enhance mesenchymal stromal/stem cell (MSC) osteogenesis. Moreover, by combining this material with biochemical paracrine factors released by statically cultured and mechanically stimulated osteocytes, we further mirrored the biochemical environment of the bone niche, enhancing stromal/stem cell viability, differentiation, and matrix deposition. Therefore, this biomimetic material represents a novel approach to promote skeletal repair.
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Affiliation(s)
- Laurens Parmentier
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2 D02 R590, Ireland
- Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland
- Polymer Chemistry and Biomaterials Group, Centre of Macromolecular Chemistry (CMaC), Department of Organic and Macromolecular Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Mathieu Riffault
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2 D02 R590, Ireland
- Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland
- Advanced Materials and Bioengineering Research Centre, Trinity College Dublin & RCSI, Dublin 2 D02 VN51, Ireland
| | - David A. Hoey
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2 D02 R590, Ireland
- Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland
- Advanced Materials and Bioengineering Research Centre, Trinity College Dublin & RCSI, Dublin 2 D02 VN51, Ireland
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26
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Hu Z, Zhang L, Wang H, Wang Y, Tan Y, Dang L, Wang K, Sun Z, Li G, Cao X, Zhang S, Shi F, Zhang G. Targeted silencing of miRNA-132-3p expression rescues disuse osteopenia by promoting mesenchymal stem cell osteogenic differentiation and osteogenesis in mice. Stem Cell Res Ther 2020; 11:58. [PMID: 32054528 PMCID: PMC7020585 DOI: 10.1186/s13287-020-1581-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/07/2020] [Accepted: 02/04/2020] [Indexed: 01/03/2023] Open
Abstract
Background Skeletal unloading can induce severe disuse osteopenia that often occurs in spaceflight astronauts or in patients subjected to prolonged bed-rest or immobility. Previously, we revealed a mechano-sensitive factor, miRNA-132-3p, that is closely related to the osteoblast function. The aim of this study was to investigate whether miRNA-132-3p could be an effective target for treating disuse osteopenia. Methods The 2D-clinostat device and the hindlimb-unloaded (HU) model were used to copy the mechanical unloading condition at the cellular and animal levels, respectively. Mimics or inhibitors of miRNA-132-3p were used to interfere with the expression of miRNA-132-3p in bone marrow-derived mesenchymal stem cells (BMSCs) in vitro for analyzing the effects on osteogenic differentiation. The special in vivo antagonists of miRNA-132-3p was delivered to the bone formation regions of HU mice for treating disuse osteopenia by a bone-targeted (AspSerSer)6-cationic liposome system. The bone mass, microstructure, and strength of the hindlimb bone tissue were analyzed for evaluating the therapeutic effect in vivo. Results miRNA-132-3p expression was declined under normal conditions and increased under gravitational mechanical unloading conditions during osteogenic differentiation of BMSCs in vitro. The upregulation of miRNA-132-3p expression resulted in the inhibition of osteogenic differentiation, whereas the downregulation of miRNA-132-3p expression enhanced osteogenic differentiation. The inhibition of miRNA-132-3p expression was able to attenuate the negative effects of mechanical unloading on BMSC osteogenic differentiation. Most importantly, the targeted silencing of miRNA-132-3p expression in the bone tissues could effectively preserve bone mass, microstructure, and strength by promoting osteogenic differentiation and osteogenesis in HU mice. Conclusion The overexpression of miRNA-132-3p induced by mechanical unloading is disadvantageous for BMSC osteogenic differentiation and osteogenesis. Targeted silencing of miRNA-132-3p expression presents a potential therapeutic target for the prevention and treatment of disuse osteoporosis.
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Affiliation(s)
- Zebing Hu
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Lijun Zhang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Han Wang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China.,Department of Orthopedics, Affiliated Hospital of Air Force Aviation Medicine Research Institute, Air Force Medical University, Beijing, 100089, China
| | - Yixuan Wang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Yingjun Tan
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Lei Dang
- Institute for Advancing Translational Medicine in Bone & Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Ke Wang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Zhongyang Sun
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China.,Department of Orthopedics, No. 454 Hospital of PLA, Nanjing, 210002, China
| | - Gaozhi Li
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Xinsheng Cao
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Shu Zhang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Fei Shi
- The Key Laboratory of Aerospace Medicine, Ministry of Education, Air Force Medical University, Xi'an, 710032, Shaanxi, China.
| | - Ge Zhang
- Institute for Advancing Translational Medicine in Bone & Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China.
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27
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Zannit HM, Silva MJ. Proliferation and Activation of Osterix-Lineage Cells Contribute to Loading-Induced Periosteal Bone Formation in Mice. JBMR Plus 2019; 3:e10227. [PMID: 31768488 PMCID: PMC6874181 DOI: 10.1002/jbm4.10227] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/12/2019] [Accepted: 08/02/2019] [Indexed: 12/27/2022] Open
Abstract
Mechanical loading stimulates bone formation. Bone-lining-cell activation and cell proliferation have been implicated in this process. However, the origin of osteoblasts that form bone following mechanical stimulation remains unknown. Our objective was to identity the contributions of activation, differentiation, and proliferation of osteoblast lineage cells to loading-induced periosteal bone formation. Tamoxifen-inducible Osx-Cre-ERT2;Ai9/TdTomato reporter mice (male and female) were aged to young adult (5 months) and middle age (12 months), and were administered tamoxifen for 5 consecutive days to label osterix-lineage cells. Following a 3-week clearance period, mice were subjected to five consecutive bouts of unilateral axial tibial compression. We first confirmed this protocol stimulated an increase in periosteal bone formation that was primarily lamellar apposition. Next, mice received 5-bromo-2'-deoxyuridine (BrdU) in their drinking water daily to label proliferating cells; calcein was given to label active mineralizing surfaces. Tibias were harvested after the fifth loading day and processed for frozen undecalcified histology. The middiaphyseal periosteal surface in the region of peak bone formation was analyzed. Histology revealed both nonloaded and loaded tibias were covered in osterix positive (Osx+) cells on the periosteal surface of both 5- and 12-month-old animals. There was a significant increase in the mineralizing surface (calcein+) covered with Osx+ cells in loaded versus control limbs. Furthermore, nearly all of the mineralizing surfaces (>95%) were lined with Osx+ cells. We also observed approximately 30% of Osx+ cells were also BrdU+, indicating they arose via proliferation. These results show that following mechanical loading, pre-existing cells of the Osx lineage cover the vast majority of surfaces where there is active loading-induced bone formation, and a portion of these cells proliferated in the 5-day loading period. We conclude the initial anabolic response after mechanical loading is based on the activation and proliferation of Osx lineage cells, not the differentiation of progenitor cells. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Heather M Zannit
- Department of Orthopaedic Surgery and Department of Biomedical EngineeringWashington UniversitySt LouisMO63110USA
| | - Matthew J Silva
- Department of Orthopaedic Surgery and Department of Biomedical EngineeringWashington UniversitySt LouisMO63110USA
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