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Brent MB. Pharmaceutical treatment of bone loss: From animal models and drug development to future treatment strategies. Pharmacol Ther 2023; 244:108383. [PMID: 36933702 DOI: 10.1016/j.pharmthera.2023.108383] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/18/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023]
Abstract
Animal models are fundamental to advance our knowledge of the underlying pathophysiology of bone loss and to study pharmaceutical countermeasures against it. The animal model of post-menopausal osteoporosis from ovariectomy is the most widely used preclinical approach to study skeletal deterioration. However, several other animal models exist, each with unique characteristics such as bone loss from disuse, lactation, glucocorticoid excess, or exposure to hypobaric hypoxia. The present review aimed to provide a comprehensive overview of these animal models to emphasize the importance and significance of investigating bone loss and pharmaceutical countermeasures from perspectives other than post-menopausal osteoporosis only. Hence, the pathophysiology and underlying cellular mechanisms involved in the various types of bone loss are different, and this might influence which prevention and treatment strategies are the most effective. In addition, the review sought to map the current landscape of pharmaceutical countermeasures against osteoporosis with an emphasis on how drug development has changed from being driven by clinical observations and enhancement or repurposing of existing drugs to today's use of targeted anti-bodies that are the result of advanced insights into the underlying molecular mechanisms of bone formation and resorption. Moreover, new treatment combinations or repurposing opportunities of already approved drugs with a focus on dabigatran, parathyroid hormone and abaloparatide, growth hormone, inhibitors of the activin signaling pathway, acetazolamide, zoledronate, and romosozumab are discussed. Despite the considerable progress in drug development, there is still a clear need to improve treatment strategies and develop new pharmaceuticals against various types of osteoporosis. The review also highlights that new treatment indications should be explored using multiple animal models of bone loss in order to ensure a broad representation of different types of skeletal deterioration instead of mainly focusing on primary osteoporosis from post-menopausal estrogen deficiency.
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Affiliation(s)
- Mikkel Bo Brent
- Department of Biomedicine, Aarhus University, Denmark, Wilhelm Meyers Allé 3, 8000 Aarhus C, Denmark.
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2
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Yu BF, Wang Z, Chen XX, Zeng Q, Dai CC, Wei J. Continuous dynamic identification of key genes and molecular signaling pathways of periosteum in guided bone self-generation in swine model. J Orthop Surg Res 2023; 18:53. [PMID: 36653843 PMCID: PMC9847205 DOI: 10.1186/s13018-023-03524-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/10/2023] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Guided bone self-generation with periosteum-preserved has successfully regenerated mandibular, temporomandibular and interphalangeal joint. The aim of this study was to investigate the dynamic changes of gene expression of periosteum which was involved in the guided bone self-generation. METHODS Rib defects of critical size were created in mature swine with periosteum-preserved. The periosteum was sutured into a sealed sheath that closed the bone defect. The periosteum of trauma and control sites were harvested at postoperative 9 time points, and total RNA was extracted. Microarray analysis was conducted to identify the differences in the transcriptome of different time points between two groups. RESULTS The differentially expressed genes (DEGs) between control and trauma group were different at postoperative different time points. The dynamic changes of the number of DEGs fluctuated a lot. There were 3 volatility peaks, and we chose 3 time points of DEG number peak (1 week, 5 weeks and 6 months) to study the functions of DEGs. Oxidoreductase activity, oxidation-reduction process and mitochondrion are the most enriched terms of Go analysis. The major signaling pathways of DEGs enrichment include oxidative phosphorylation, PI3K-Akt signaling pathway, osteoclast differentiation pathway and Wnt signaling. CONCLUSIONS The oxidoreductase reaction was activated during this bone regeneration process. The oxidative phosphorylation, PI3K-Akt signaling pathway, osteoclast differentiation pathway and Wnt signaling may play important roles in the guided bone self-generation with periosteum-preserved. This study can provide a reference for how to improve the application of this concept of bone regeneration.
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Affiliation(s)
- Bao-Fu Yu
- grid.412523.30000 0004 0386 9086Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, No. 639 Zhi Zao Ju Road, Shanghai, 200011 China
| | - Zi Wang
- grid.412523.30000 0004 0386 9086Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, No. 639 Zhi Zao Ju Road, Shanghai, 200011 China
| | - Xiao-Xue Chen
- grid.412523.30000 0004 0386 9086Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, No. 639 Zhi Zao Ju Road, Shanghai, 200011 China
| | - Qi Zeng
- grid.415002.20000 0004 1757 8108Department of Plastic Surgery, Jiangxi Province People’s Hospital, Nanchang, China
| | - Chuan-Chang Dai
- grid.412523.30000 0004 0386 9086Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, No. 639 Zhi Zao Ju Road, Shanghai, 200011 China
| | - Jiao Wei
- grid.412523.30000 0004 0386 9086Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, No. 639 Zhi Zao Ju Road, Shanghai, 200011 China
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Maitiabula G, Tian F, Wang P, Zhang L, Gao X, Wan S, Sun H, Yang J, Zhang Y, Gao T, Xue B, Li C, Li J, Wang X. Liver PP2A-Cα Protects From Parenteral Nutrition-associated Hepatic Steatosis. Cell Mol Gastroenterol Hepatol 2022; 14:669-692. [PMID: 35643235 PMCID: PMC9421584 DOI: 10.1016/j.jcmgh.2022.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Parenteral nutrition (PN) is a lifesaving therapy for patients with intestinal failure. Hepatic steatosis is a potentially fatal complication of long-term PN, but the involved pathological mechanisms are incompletely unclarified. Herein, we identify the role of protein phosphatase 2A (PP2A) in the pathogenesis of parenteral nutrition-associated hepatic steatosis (PNAHS). METHODS Proteomic/phosphoproteomic analyses of liver samples from patients with PNAHS were applied to identify the mechanism of PNAHS. Total parenteral nutrition (TPN) mice model, in vivo, and in vitro experiments were used to assess the effect of PP2A-Cα on liver fatty acid metabolism. RESULTS Reduced expression of PP2A-Cα (catalytic subunit) enhanced activation of serine/threonine kinase Akt2 and decreased activation of adenosine monophosphate-activated protein kinase (AMPK) were associated with hepatic steatosis in patients with PNAHS. Mice given PN for 14 days developed hepatic steatosis, down-regulation of PP2A-Cα, activation of Akt2, and inhibition of AMPK. Hepatocyte-specific deletion of PP2A-Cα in mice given PN exacerbated Akt2 activation, AMPK inhibition, and hepatic steatosis through an effect on fatty acid degradation, whereas hepatocyte-specific PP2A-Cα overexpression significantly ameliorated hepatic steatosis accompanied with Akt2 suppression and AMPK activation. Additionally, pharmacological activation of Akt2 in mice overexpressing PP2A-Cα led to the aggravation of hepatic steatosis. CONCLUSIONS Our findings demonstrate that hepatic PP2A-Cα serves as a protective factor of PNAHS due to ameliorating hepatic steatosis and improving liver function. Our study provides a strong rationale that PP2A-Cα may be involved in the pathogenesis of PNAHS.
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Affiliation(s)
- Gulisudumu Maitiabula
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Feng Tian
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Peng Wang
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Li Zhang
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xuejin Gao
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Songlin Wan
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Haifeng Sun
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Jianbo Yang
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yupeng Zhang
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Tingting Gao
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Bin Xue
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of the Medical School of Nanjing University, Nanjing, China,Core Laboratory, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China,Bin Xue, PhD, LongMian Avenue, Nanjing 211166, China. tel: +86-25-87115542
| | - Chaojun Li
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of the Medical School of Nanjing University, Nanjing, China,Chaojun Li, PhD, Hankou Road, Nanjing, 210093, China. tel: +86-25-83596289.
| | - Jieshou Li
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xinying Wang
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China,Correspondence Address correspondence to: Xinying Wang, MD, PhD, Department of General Surgery, Jinling Hospital, Medical School of Nanjing University. 305 East Zhongshan Road, Nanjing, 210002, China. tel: +86-25-80861429
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Xie P, Zhu JG, Liu Y, Liu TW, Xu YG, Gong DQ. Effect of Akt activation on apoptosis-related gene expression in the crop tissues of male and female pigeons (Columba livia). Poult Sci 2021; 100:101392. [PMID: 34425554 PMCID: PMC8383011 DOI: 10.1016/j.psj.2021.101392] [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] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/05/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022] Open
Abstract
The current study investigated whether the expression of apoptosis genes in the pigeon crops was affected by the Akt signaling pathway during crop milk formation. First, 78 pairs of adult White King pigeons were randomly assigned to 7 groups, and the expression of apoptosis-related genes and Akt signaling pathway-related proteins in the crop tissues during different breeding stages were examined. The results showed that the mRNA levels of Bak, caspase-3, caspase-6, and caspase-9 in female crops all increased and reached their highest levels at d 17 of incubation (I17). In male crops, the levels of caspase-3 and caspase-9 gene expression peaked at d 1 of chick rearing (R1). The lowest level of Bcl-2 gene expression in females was observed at I17. The expression ratios of p-Akt (Ser473)/Akt and p-Akt (Thr308)/Akt in male crops decreased to their minimum at R1, while it was observed at d 7 of chick rearing (R7) in females. Second, 36 pairs of adult pigeons were divided into 3 groups and were subjected to SC79 injections with dosages of 0, 0.02, or 0.04 mg/kg bodyweight. The SC79 injections resulted in a considerable decrease in growth performance of pigeon squabs. In male crops, the expression ratios of p-Akt (Ser473)/Akt and p-Akt (Thr308)/Akt were significantly elevated in the 0.02 mg/kg SC79 group, while in female crops, they were higher in the 0.04 mg/kg SC79 group (P < 0.05). The SC79 injection inhibited the gene expression of Bak in female crops, but enhanced the gene expression of Bcl-2 in both male and female crops. In the 0.04 mg/kg SC79 group, a 50.7 to 75.7% decrease was observed in the expression of caspase-3, caspase-6, and caspase-9 in male and female pigeon crops. Expression of the caspase-8 gene and total Akt protein in pigeon crops was not changed in different breeding stages or after SC79 injection. In conclusion, the expression of genes related to mitochondria-dependent apoptosis can be regulated by the Akt signaling pathway, which may play a potential role in pigeon milk formation.
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Affiliation(s)
- P Xie
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China; Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology, Huaiyin Normal University, Huaian 223300, China.
| | - J G Zhu
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Y Liu
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China
| | - T W Liu
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology, Huaiyin Normal University, Huaian 223300, China
| | - Y G Xu
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology, Huaiyin Normal University, Huaian 223300, China
| | - D Q Gong
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
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FN1 promotes chondrocyte differentiation and collagen production via TGF-β/PI3K/Akt pathway in mice with femoral fracture. Gene 2020; 769:145253. [PMID: 33098939 DOI: 10.1016/j.gene.2020.145253] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/17/2020] [Accepted: 10/16/2020] [Indexed: 11/24/2022]
Abstract
Fibronectin (FN) functions as a potent stimulator of osteogenic differentiation, and bone fracture healing. In FN family, FN1 acts as an interactive protein gene product to mediate chondrocyte adhesion. However, its effect on fracture healing remains elusive. Therefore, we aimed to investigate the involvement of FN1 in fracture healing. Hard callus formations were found at fracture site with thicker periosteum in lateral cortical bone area outside the fracture site in model mice. The decreased number of osteogenic cells in the middle of the callus region and increased extracellular matrix were suggestive of successful induction. Immunoblotting and RT-qPCR revealed that expression of FN1 was increased in tissues of fracture mice. As displayed by Safranin-fast green staining hematoxylin-eosin staining, the overexpression of FN1 at fracture site promoted osteoid formation and chondrocyte differentiation. The stimulating role of FN1 in collagen production was evidenced by increased levels of Col2, Col1, ColX, Osteonectin, and Osteocalcin and enhanced BMD, BV, BV/TV and Tb.Th values verified by immunoblotting and immunohistochemical staining. Additionally, the upregulation of FN1 contributed to promoted TGF-β, c-Caspase-9/t-Caspase-9 ratio and NF-κB p65 protein expression as well as lowered p-PI3K/PI3K and p-AKT/AKT ratios, implying the positive correlation between FN1 and the TGF-β/PI3K/Akt signaling pathway. The key findings of the present study provided evidence indicating that overexpression of FN1 contributes to fracture healing by activation of the TGF-β/PI3K/Akt signaling pathway.
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Sun Y, Dai S, Tao J, Li Y, He Z, Liu Q, Zhao J, Deng Y, Kang J, Zhang X, Yang S, Liu Y. Taurine suppresses ROS-dependent autophagy via activating Akt/mTOR signaling pathway in calcium oxalate crystals-induced renal tubular epithelial cell injury. Aging (Albany NY) 2020; 12:17353-17366. [PMID: 32931452 PMCID: PMC7521519 DOI: 10.18632/aging.103730] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 05/25/2020] [Indexed: 01/24/2023]
Abstract
Oxidative stress and autophagy are the key promoters of calcium oxalate (CaOx) nephrolithiasis. Taurine is an antioxidant that plays a protective role in the pathogenesis of kidney disease. Previous studies found that taurine suppressed cellular oxidative stress, and inhibited autophagy activation. However, the effect of taurine on CaOx kidney stone formation remains unknown. In the present work, we explored the regulatory effects of taurine on CaOx crystals-induced HK-2 cell injury. Results showed that pretreatment with taurine significantly enhanced the viability of HK-2 cells and ameliorated kidney tissue injury induced by CaOx crystals. Taurine also markedly reduced the levels of inflammatory cytokines, apoptosis, and CaOx crystals deposition. Furthermore, we observed that taurine supplementation alleviated CaOx crystals-induced autophagy. Mechanism studies showed that taurine reduced oxidative stress via increasing SOD activity, reducing MDA concentration, alleviating mitochondrial oxidative injury, and decreasing the production of intracellular ROS. Taurine treatment also effectively activated Akt/mTOR signaling pathway in CaOx crystals-induced HK-2 cells both in vitro and in vivo. In summary, the current study shows that taurine inhibits ROS-dependent autophagy via activating Akt/mTOR signaling pathway in CaOx crystals-induced HK-2 cell and kidney injury, suggesting that taurine may serve as an effective therapeutic agent for the treatment of CaOx nephrolithiasis.
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Affiliation(s)
- Yan Sun
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Shiting Dai
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jin Tao
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yunlong Li
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ziqi He
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Quan Liu
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jiawen Zhao
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yaoliang Deng
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Juening Kang
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xuepei Zhang
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Sixing Yang
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yunlong Liu
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Hofman M, Kolejewska A, Greven J, Andruszkow H, Kobbe P, Tolba R, Hildebrand F, Poeze M. Gait analysis and muscle weight analysis after lower extremity fractures in a small animal model. Gait Posture 2020; 77:207-213. [PMID: 32058285 DOI: 10.1016/j.gaitpost.2020.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/21/2020] [Accepted: 01/23/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Besides adequate healing of bone and soft tissues, mobility represents a significant factor in functional outcome after lower extremity fractures. Although gait analysis is gaining clinical interest and importance in the rehabilitation of patients with fractures, it is rarely used in experimental fracture healing research. The aim of this study is to establish an accurate gait analysis method for fracture healing research in small animal models and to evaluate the influence of a lower extremity fracture on gait pattern and muscle atrophy in rats. RESEARCH QUESTION How does an intramedullary stabilized femur fracture influence the gait pattern and muscle atrophy during fracture healing in rats? METHODS An isolated femur fracture with intramedullary stabilization was induced in 26 Sprague Dawley rats. Different gait parameters (e.g. intensity, print area, stand duration, duty cycle, and swing speed) were evaluated with the CatWalk gait analysis system during the fracture healing process. Furthermore, muscle weight analysis was performed at different time points. RESULTS The gait analyses with the CatWalk system showed a high correlation with the osteogenesis of fracture healing in this model. Muscle atrophy increased during the early fracture healing stages and then decreased in the later stages. SIGNIFICANCE We are the first to show that the CatWalk system is a useful tool to perform gait analyses after lower extremity fractures in a murine model. These results could form a basis for future gait analyses research in fracture healing studies to improve knowledge about bone regeneration and rehabilitation after lower extremity fractures.
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Affiliation(s)
- Martijn Hofman
- Department of Orthopaedic Trauma and Reconstructive Surgery, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Aneta Kolejewska
- Department of Orthopaedic Trauma and Reconstructive Surgery, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Johannes Greven
- Department of Orthopaedic Trauma and Reconstructive Surgery, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Hagen Andruszkow
- Department of Orthopaedic Trauma and Reconstructive Surgery, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Philipp Kobbe
- Department of Orthopaedic Trauma and Reconstructive Surgery, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Rene Tolba
- Institute of Laboratory Animal Science, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Frank Hildebrand
- Department of Orthopaedic Trauma and Reconstructive Surgery, University of Aachen Medical Center, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Martijn Poeze
- Department of Surgery, Division of Traumasurgery, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, Netherlands.
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8
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Sun X, Gao X, Deng Z, Zhang L, McGilvray K, Gadomski BC, Amra S, Bao G, Huard J. High bone microarchitecture, strength, and resistance to bone loss in MRL/MpJ mice correlates with activation of different signaling pathways and systemic factors. FASEB J 2019; 34:789-806. [PMID: 31914651 DOI: 10.1096/fj.201901229rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 10/30/2019] [Accepted: 11/02/2019] [Indexed: 12/27/2022]
Abstract
The MRL/MpJ mice have demonstrated an enhanced tissue regeneration capacity for various tissues. In the present study, we systematically characterized bone microarchitecture and found that MRL/MpJ mice exhibit higher bone microarchitecture and strength compared to both C57BL/10J and C57BL/6J WT mice at 2, 4, and 10 months of age. The higher bone mass in MRL/MpJ mice was correlated to increased osteoblasts, decreased osteoclasts, higher cell proliferation, and bone formation, and enhanced pSMAD5 signaling earlier during postnatal development (2-month old) in the spine trabecular bone, and lower bone resorption rate at later age. Furthermore, these mice exhibit accelerated fracture healing via enhanced pSMAD5, pAKT and p-P38MAPK pathways compared to control groups. Moreover, MRL/MpJ mice demonstrated resistance to ovariectomy-induced bone loss as evidenced by maintaining higher bone volume/tissue volume (BV/TV) and lower percentage of bone loss later after ovariectomy. The consistently higher serum IGF1 level and lower RANKL level in MRL/MpJ mice may contribute to the maintenance of high bone mass in uninjured and injured bone. In conclusion, our results indicate that enhanced pSMAD5, pAKT, and p-P38MAPK signaling, higher serum IGF-1, and lower RANKL level contribute to the higher bone microarchitecture and strength, accelerated healing, and resistance to osteoporosis in MRL/MpJ mice.
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Affiliation(s)
- Xuying Sun
- Department of Orthopaedic Surgery, The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Xueqin Gao
- Department of Orthopaedic Surgery, The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas.,Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, Colorado
| | - Zhenhan Deng
- Department of Orthopaedic Surgery, The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Linlin Zhang
- Department of Biomedical Engineering, Rice University, Houston, Texas
| | - Kirk McGilvray
- Orthopaedic Bioengineering Research Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado
| | - Benjamin C Gadomski
- Orthopaedic Bioengineering Research Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado
| | - Sarah Amra
- Department of Orthopaedic Surgery, The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Gang Bao
- Department of Biomedical Engineering, Rice University, Houston, Texas
| | - Johnny Huard
- Department of Orthopaedic Surgery, The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas.,Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, Colorado
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Doherty L, Yu J, Wang X, Hankenson KD, Kalajzic I, Sanjay A. A PDGFRβ-PI3K signaling axis mediates periosteal cell activation during fracture healing. PLoS One 2019; 14:e0223846. [PMID: 31665177 PMCID: PMC6821073 DOI: 10.1371/journal.pone.0223846] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/30/2019] [Indexed: 12/21/2022] Open
Abstract
Insufficient and delayed fracture healing remain significant public health problems with limited therapeutic options. Phosphoinositide 3-kinase (PI3K) signaling, a major pathway involved in regulation of fracture healing, promotes proliferation, migration, and differentiation of osteoprogenitors. We have recently reported that knock-in mice with a global increase in PI3K signaling (gCblYF) show enhanced femoral fracture healing characterized by an extraordinary periosteal response to injury. Interestingly, of all growth factor receptors involved in fracture healing, PI3K directly binds only to PDGFR. Given these findings, we hypothesized a PDGFR-PI3K interaction is necessary for mediating robust periosteal cell activation following fracture. In this study, we isolated primary periosteal cells from gCblYF mice to analyze cross-talk between the PDGFRβ and PI3K signaling pathways. We found PDGFRβ signaling contributes to robust Akt phosphorylation in periosteal cells in comparison with other growth factor signaling pathways. Additionally, we performed femoral fractures on gCblYF mice with a conditional removal of PDGFRβ in mesenchymal progenitors using inducible alpha smooth muscle actin (αSMA) CreERT2 mice. Our studies showed that depletion of PDGFRβ signaling within these progenitors in the early phase of fracture healing significantly abrogates PI3K-mediated periosteal activation and proliferation three days after fracture. Combined, these results suggest that PDGFRβ signaling through PI3K is necessary for robust periosteal activation in the earliest phases of fracture healing.
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Affiliation(s)
- Laura Doherty
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, United States of America
| | - Jungeun Yu
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, United States of America
| | - Xi Wang
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut, United States of America
| | - Kurt D. Hankenson
- Department of Orthopaedic Surgery, School of Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, UConn Health, Farmington, Connecticut, United States of America
| | - Archana Sanjay
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, United States of America
- * E-mail:
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