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Chen X, Wang C, Zhao G, Li Z, Zhang W, Song T, Zhang C, Duan N. Suppression of DNMT2/3 by proinflammatory cytokines inhibits CtBP1/2-dependent genes to promote the occurrence of atrophic nonunion. Cytokine 2024; 173:156436. [PMID: 37979214 DOI: 10.1016/j.cyto.2023.156436] [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: 04/29/2023] [Revised: 10/14/2023] [Accepted: 11/07/2023] [Indexed: 11/20/2023]
Abstract
Failure of bone healing after fracture often results in nonunion, but the underlying mechanism of nonunion pathogenesis is poorly understood. Herein, we provide evidence to clarify that the inflammatory microenvironment of atrophic nonunion (AN) mice suppresses the expression levels of DNA methyltransferases 2 (DNMT2) and 3A (DNMT3a), preventing the methylation of CpG islands on the promoters of C-terminal binding protein 1/2 (CtBP1/2) and resulting in their overexpression. Increased CtBP1/2 acts as transcriptional corepressors that, along with histone acetyltransferase p300 and Runt-related transcription factor 2 (Runx2), suppress the expression levels of six genes involved in bone healing: BGLAP (bone gamma-carboxyglutamate protein), ALPL (alkaline phosphatase), SPP1 (secreted phosphoprotein 1), COL1A1 (collagen 1a1), IBSP (integrin binding sialoprotein), and MMP13 (matrix metallopeptidase 13). We also observe a similar phenomenon in osteoblast cells treated with proinflammatory cytokines or treated with a DNMT inhibitor (5-azacytidine). Forced expression of DNMT2/3a or blockage of CtBP1/2 with their inhibitors can reverse the expression levels of BGLAP/ALPL/SPP1/COL1A1/IBSP/MMP13 in the presence of proinflammatory cytokines. Administration of CtBP1/2 inhibitors in fractured mice can prevent the incidence of AN. Thus, we demonstrate that the downregulation of bone healing genes dependent on proinflammatory cytokines/DNMT2/3a/CtBP1/2-p300-Runx2 axis signaling plays a critical role in the pathogenesis of AN. Disruption of this signaling may represent a new therapeutic strategy to prevent AN incidence after bone fracture.
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Affiliation(s)
- Xun Chen
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Chaofeng Wang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Guolong Zhao
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Zhong Li
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Wentao Zhang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Tao Song
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Congming Zhang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China.
| | - Ning Duan
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China.
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Saul D, Menger MM, Ehnert S, Nüssler AK, Histing T, Laschke MW. Bone Healing Gone Wrong: Pathological Fracture Healing and Non-Unions-Overview of Basic and Clinical Aspects and Systematic Review of Risk Factors. BIOENGINEERING (BASEL, SWITZERLAND) 2023; 10:bioengineering10010085. [PMID: 36671657 PMCID: PMC9855128 DOI: 10.3390/bioengineering10010085] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/31/2022] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
Bone healing is a multifarious process involving mesenchymal stem cells, osteoprogenitor cells, macrophages, osteoblasts and -clasts, and chondrocytes to restore the osseous tissue. Particularly in long bones including the tibia, clavicle, humerus and femur, this process fails in 2-10% of all fractures, with devastating effects for the patient and the healthcare system. Underlying reasons for this failure are manifold, from lack of biomechanical stability to impaired biological host conditions and wound-immanent intricacies. In this review, we describe the cellular components involved in impaired bone healing and how they interfere with the delicately orchestrated processes of bone repair and formation. We subsequently outline and weigh the risk factors for the development of non-unions that have been established in the literature. Therapeutic prospects are illustrated and put into clinical perspective, before the applicability of biomarkers is finally discussed.
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Affiliation(s)
- Dominik Saul
- Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tübingen, BG Trauma Center Tübingen, 72076 Tübingen, Germany
- Kogod Center on Aging and Division of Endocrinology, Mayo Clinic, Rochester, MN 55905, USA
- Institute for Clinical and Experimental Surgery, Saarland University, 66421 Homburg, Germany
- Correspondence:
| | - Maximilian M. Menger
- Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tübingen, BG Trauma Center Tübingen, 72076 Tübingen, Germany
- Institute for Clinical and Experimental Surgery, Saarland University, 66421 Homburg, Germany
| | - Sabrina Ehnert
- Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tübingen, BG Trauma Center Tübingen, 72076 Tübingen, Germany
| | - Andreas K. Nüssler
- Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tübingen, BG Trauma Center Tübingen, 72076 Tübingen, Germany
| | - Tina Histing
- Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tübingen, BG Trauma Center Tübingen, 72076 Tübingen, Germany
| | - Matthias W. Laschke
- Institute for Clinical and Experimental Surgery, Saarland University, 66421 Homburg, Germany
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Lotzien S, Rosteius T, Jettkant B, Cibura C, Rausch V, Schildhauer TA, Geßmann J. Locking the Taylor Spatial Frame - The effect of three additional longitudinal rods on osteotomy site movements. Clin Biomech (Bristol, Avon) 2022; 100:105820. [PMID: 36401977 DOI: 10.1016/j.clinbiomech.2022.105820] [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: 05/09/2022] [Revised: 10/21/2022] [Accepted: 11/09/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND In clinical practice, even when the fixator is locked, a noticeable laxity of the construct can be observed. This study was designed to measure the stiffness of the fixator and to analyze the movements of the osteotomy site. Furthermore, the effect of three additional longitudinal rods on the locking of the construct was analyzed. METHODS Five synthetic tibia/fixator models (Model A) were tested under rotational torque (40 Nm) and axial compression (700 N). Three additional rigid rods were subsequently mounted, and the tests were repeated (Model B). The movements of the fixator as well as the osteotomy site were registered by a digital optical measurement system. Load- deformation curves, and so stiffness of the models, were calculated and compared. FINDINGS Under rotational and axial loadings, Model A was found to be less rigid than Model B (p = 0.034; p = 0.194). Notably, Model A showed a region of laxity around neutral rotational (ΔF = 5 Nm) and axial (ΔF = 16.64 N) loading before a linear deformation trend was measured. Concomitantly, greater osteotomy site movement was measured for Model A than for Model B under full loading (p = 0.05) and within the region of increased laxity (p = 0.042). INTERPRETATION The fixator showed an element of laxity around neutral axial and rotational loading, which transferred to the bone and led to a notable amount of osteotomy gap movement. Mounting three additional rods increased the stiffness of the construct and therefore reduced the movement of the osteotomy site.
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Affiliation(s)
- Sebastian Lotzien
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany.
| | - Thomas Rosteius
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany
| | - Birger Jettkant
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany
| | - Charlotte Cibura
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany
| | - Valentin Rausch
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany
| | - Thomas Armin Schildhauer
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany
| | - Jan Geßmann
- Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Bürkle- de-la-Camp Platz 1, 44789 Bochum, Germany
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Kostiv RE, Matveeva NY, Kalinichenko SG. Localization of VEGF, TGF-β1, BMP-2, and Apoptosis Factors in Hypertrophic Nonunion of Human Tubular Bones. Bull Exp Biol Med 2022; 173:160-168. [PMID: 35624354 DOI: 10.1007/s10517-022-05513-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Indexed: 11/29/2022]
Abstract
We studied localization of VEGF, TGF-β1, BMP-2, caspase-3, Bcl-2, and TNFα in the callus samples obtained from 5 patients (4 women and 1 man) aged 41-53 years during planned surgery for nonunion and pseudarthrosis of the clavicle (n=1), ulna (n=1), femur (n=1), and tibia (n=2) bones. Two control groups included material of hypertrophied callus (n=3) with consolidated fractures of long bones and samples of intact bones (n=3) obtained by postmortem autopsy of subjects without pathology of the musculoskeletal system. A nonuniform distribution of the studied markers was revealed. Active expression of VEGF was observed in fibroblast-like cells of the fibrous tissue, osteoblasts of the periosteum and osteons. Osteoblasts expressing BMP-2 were localized in the periosteum and the loose connective tissue of the Haversian canals. The number of immunopositive cells expressing TGF-β1 and TNFα in the callus exceeded that in the control and correlated with the expression of caspase-3 in fibroblast-like cells, osteoblasts, chondroblasts, and microvascular endotheliocytes. The results allow considering fracture nonunion as a result of overproduction of cytotoxic and proapoptotic factors in chronic inflammation and dysfunction of the expression of morphogenetic proteins. The morphochemical patterns of the studied markers open up prospects for the development of new methods of pharmacological correction of fracture repair.
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Affiliation(s)
- R E Kostiv
- Department of Histology, Embryology, and Cytology, Pacific State Medical University, Ministry of Health of the Russian Federation, Vladivostok, Russia
| | - N Yu Matveeva
- Department of Histology, Embryology, and Cytology, Pacific State Medical University, Ministry of Health of the Russian Federation, Vladivostok, Russia.
| | - S G Kalinichenko
- Department of Histology, Embryology, and Cytology, Pacific State Medical University, Ministry of Health of the Russian Federation, Vladivostok, Russia
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Hormone sensitive lipase ablation promotes bone regeneration. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166449. [PMID: 35618183 DOI: 10.1016/j.bbadis.2022.166449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/08/2022] [Accepted: 05/13/2022] [Indexed: 02/07/2023]
Abstract
There is an inverse relationship between the differentiation of mesenchymal stem cells (MSCs) along either an adipocyte or osteoblast lineage, with lineage differentiation known to be mediated by transcription factors PPARγ and Runx2, respectively. Endogenous ligands for PPARγ are generated during the hydrolysis of triacylglycerols to fatty acids through the actions of lipases such as hormone sensitive lipase (HSL). To examine whether reduced production of endogenous PPARγ ligands would influence bone regeneration, we examined the effects of HSL knockout on fracture repair in mice using a tibial mono-cortical defect as a model. We found an improved rate of fracture repair in HSL-ko mice documented by serial μCT and bone histomorphometry compared to wild-type (WT) mice. Similarly, accelerated rates of bone regeneration were observed with a calvarial model where implantation of bone grafts from HSL-ko mice accelerated bone regeneration at the injury site. Further analysis revealed improved MSC differentiation down osteoblast and chondrocyte lineage with inhibition of HSL. MSC recruitment to the injury site was greater in HSL-ko mice than WT. Finally, we used single cell RNAseq to understand the osteoimmunological differences between WT and HSL-ko mice and found changes in the pre-osteoclast population. Our study shows HSL-ko mice as an interesting model to study improvements to bone injury repair. Furthermore, our study highlights the potential importance of pre-osteoclasts and osteoclasts in bone repair.
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Wildemann B, Ignatius A, Leung F, Taitsman LA, Smith RM, Pesántez R, Stoddart MJ, Richards RG, Jupiter JB. Non-union bone fractures. Nat Rev Dis Primers 2021; 7:57. [PMID: 34354083 DOI: 10.1038/s41572-021-00289-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/24/2021] [Indexed: 11/09/2022]
Abstract
The human skeleton has remarkable regenerative properties, being one of the few structures in the body that can heal by recreating its normal cellular composition, orientation and mechanical strength. When the healing process of a fractured bone fails owing to inadequate immobilization, failed surgical intervention, insufficient biological response or infection, the outcome after a prolonged period of no healing is defined as non-union. Non-union represents a chronic medical condition not only affecting function but also potentially impacting the individual's psychosocial and economic well-being. This Primer provides the reader with an in-depth understanding of our contemporary knowledge regarding the important features to be considered when faced with non-union. The normal mechanisms involved in bone healing and the factors that disrupt the normal signalling mechanisms are addressed. Epidemiological considerations and advances in the diagnosis and surgical therapy of non-union are highlighted and the need for greater efforts in basic, translational and clinical research are identified.
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Affiliation(s)
- Britt Wildemann
- Experimental Trauma Surgery, Department of Trauma, Hand and Reconstructive Surgery, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany. .,Julius Wolff Institute and BIH Center for Regenerative Therapies (BCRT), Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany.
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, Ulm University, Ulm, Baden Württemberg, Germany
| | - Frankie Leung
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, the University of Hong Kong, Hong Kong, Hong Kong
| | - Lisa A Taitsman
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA
| | - R Malcolm Smith
- Orthopedic trauma service, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rodrigo Pesántez
- Departamento de Ortopedia Y Traumatología Fundación Santa Fé de Bogotá - Universidad de los Andes, Bogotá, Colombia
| | | | | | - Jesse B Jupiter
- Department of Orthopaedic surgery, Massachussets General Hospital, Boston, MA, USA.
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Deficiency of optineurin enhances osteoclast differentiation by attenuating the NRF2-mediated antioxidant response. Exp Mol Med 2021; 53:667-680. [PMID: 33864025 PMCID: PMC8102640 DOI: 10.1038/s12276-021-00596-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/26/2021] [Accepted: 02/03/2021] [Indexed: 02/02/2023] Open
Abstract
Abnormally increased resorption contributes to bone degenerative diseases such as Paget's disease of bone (PDB) through unclear mechanisms. Recently, the optineurin (OPTN) gene has been implicated in PDB, and global OPTN knockout mice (Optn-/-) were shown to exhibit increased formation of osteoclasts (osteoclastogenesis). Growing evidence, including our own, has demonstrated that intracellular reactive oxygen species (ROS) stimulated by receptor activator of nuclear factor kappa-B ligand (RANKL) can act as signaling molecules to promote osteoclastogenesis. Here, we report that OPTN interacts with nuclear factor erythroid-derived factor 2-related factor 2 (NRF2), the master regulator of the antioxidant response, defining a pathway through which RANKL-induced ROS could be regulated for osteoclastogenesis. In this study, monocytes from Optn-/- and wild-type (Optn+/+) mice were utilized to differentiate into osteoclasts, and both qRT-PCR and tartrate-resistant acid phosphatase (TRAP) staining showed that the Optn-/- monocytes exhibited enhanced osteoclastogenesis compared to the Optn+/+ cells. CellROX® staining, qRT-PCR, and Western blotting indicated that OPTN deficiency reduced the basal expression of Nrf2, inhibited the expression of NRF2-responsive antioxidants, and increased basal and RANKL-induced intracellular ROS levels, leading to enhanced osteoclastogenesis. Coimmunoprecipitation (co-IP) showed direct interaction, and immunofluorescence staining showed perinuclear colocalization of the OPTN-NRF2 granular structures during differentiation. Finally, curcumin and the other NRF2 activators attenuated the hyperactive osteoclastogenesis induced by OPTN deficiency. Collectively, our findings reveal a novel OPTN-mediated mechanism for regulating the NRF2-mediated antioxidant response in osteoclasts and extend the therapeutic potential of OPTN in the aging process resulting from ROS-triggered oxidative stress, which is associated with PDB and many other degenerative diseases.
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8
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Rahmati M, Stötzel S, Khassawna TE, Iskhahova K, Florian Wieland DC, Zeller Plumhoff B, Haugen HJ. Early osteoimmunomodulatory effects of magnesium-calcium-zinc alloys. J Tissue Eng 2021; 12:20417314211047100. [PMID: 34589198 PMCID: PMC8474317 DOI: 10.1177/20417314211047100] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 09/01/2021] [Indexed: 01/04/2023] Open
Abstract
Today, substantial attention is given to biomaterial strategies for bone regeneration, and among them, there is a growing interest in using immunomodulatory biomaterials. The ability of a biomaterial to induce neo vascularization and macrophage polarization is a major factor in defining its success. Magnesium (Mg)-based degradable alloys have attracted significant attention for bone regeneration owing to their biodegradability and potential for avoiding secondary removal surgeries. However, there is insufficient evidence in the literature regarding the early inflammatory responses to these alloys in vivo. In this study, we investigated the early body responses to Mg-0.45wt%Zn-0.45wt%Ca pin-shaped alloy (known as ZX00 alloy) in rat femora 2, 5, and 10 days after implantation. We used 3D micro computed tomography (µCT), histological, immunohistochemical, histomorphometrical, and small angle X-ray scattering (SAXS) analyses to study new bone formation, early macrophage polarization, neo vascularization, and bone quality at the implant bone interface. The expression of macrophage type 2 biological markers increased significantly after 10 days of Mg alloy implantation, indicating its potential in stimulating macrophage polarization. Our biomineralization results using µCT as well as histological stained sections did not indicate any statistically significant differences between different time points for both groups. The activity of alkaline phosphatase (ALP) and Runt-related transcription factor 2 (Runx 2) biological markers decreased significantly for Mg group, indicating less osteoblast activity. Generally, our results supported the potential of ZX00 alloy to enhance the expression of macrophage polarization in vivo; however, we could not observe any statistically significant changes regarding biomineralization.
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Affiliation(s)
- Maryam Rahmati
- Department of Biomaterials, Institute
for Clinical Dentistry, University of Oslo, Oslo, Norway
| | - Sabine Stötzel
- Experimental Trauma Surgery,
Justus-Liebig University Giessen, Giessen, Germany
| | - Thaqif El Khassawna
- Experimental Trauma Surgery,
Justus-Liebig University Giessen, Giessen, Germany
- Faculty of Health Sciences, University
of Applied Sciences, Giessen, Germany
| | - Kamila Iskhahova
- Institute of Metallic Biomaterials,
Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - DC Florian Wieland
- Institute of Metallic Biomaterials,
Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | | | - Håvard Jostein Haugen
- Department of Biomaterials, Institute
for Clinical Dentistry, University of Oslo, Oslo, Norway
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Wagner JM, Schmidt SV, Dadras M, Wallner C, Huber J, Sogorski A, Sacher M, Reinkemeier F, Dittfeld S, Becerikli M, Becker K, Rauch N, Lehnhardt M, Behr B. TNF-α modulation via Etanercept restores bone regeneration of atrophic non-unions. Bone 2020; 141:115569. [PMID: 32745691 DOI: 10.1016/j.bone.2020.115569] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 10/23/2022]
Abstract
Treatment of atrophic non-unions, especially in long bones is a challenging problem in orthopedic surgery due to the high revision and failure rate after surgical intervention. Subsequently, there is a certain need for a supportive treatment option besides surgical treatment. In our previous study we gained first insights into the dynamic processes of atrophic non-union formation and observed a prolonged inflammatory reaction with upregulated TNF-α levels and bone resorption. In this study we aimed to improve bone regeneration of atrophic non-unions via TNF-α modulation in a previously established murine femoral segmental defect model. Animals that developed atrophic non-unions of the femur after 5 and 10 weeks were treated systemically for 10 and 5 weeks with Etanercept, a soluble TNF-α antibody. μCT scans and histology revealed bony bridging of the fracture gap in the treatment group, while bone formation in control animals without treatment was not evident. Moreover, osteoclasts were markedly decreased via modulation of the RANKL/OPG axis due to Etanercept treatment. Additionally, immunomodulatory effects via Etanercept could be observed as further inflammatory agents, such as TGF-β, IL6, MMP9 and 13 were decreased in both treatment groups. This study is the first showing beneficial effects of Etanercept treatment on bone regeneration of atrophic non-union formation. Moreover, the results of this study provide a new and promising therapeutic option which might reduce the failure rate of revision surgeries of atrophic non-unions.
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Affiliation(s)
| | | | - Mehran Dadras
- University Hospital BG Bergmannsheil Bochum, Germany
| | | | - Julika Huber
- University Hospital BG Bergmannsheil Bochum, Germany
| | | | - Maxi Sacher
- University Hospital BG Bergmannsheil Bochum, Germany
| | | | | | | | | | | | | | - Björn Behr
- University Hospital BG Bergmannsheil Bochum, Germany.
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10
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Xie H, Liu M, Jin Y, Lin H, Zhang Y, Zheng S. miR-1323 suppresses bone mesenchymal stromal cell osteogenesis and fracture healing via inhibiting BMP4/SMAD4 signaling. J Orthop Surg Res 2020; 15:237. [PMID: 32600409 PMCID: PMC7322887 DOI: 10.1186/s13018-020-01685-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/29/2020] [Indexed: 12/14/2022] Open
Abstract
Background Atrophic non-union fractures show no radiological evidence of callus formation within 3 months of fracture. microRNA dysregulation may underlie the dysfunctional osteogenesis in atrophic non-union fractures. Here, we aimed to analyze miR-1323 expression in human atrophic non-union fractures and examine miR-1323’s underlying mechanism of action in human mesenchymal stromal cells. Methods Human atrophic non-union and standard healing fracture specimens were examined using H&E and Alcian Blue staining, immunohistochemistry, qRT-PCR, immunoblotting, and ALP activity assays. The effects of miR-1323 mimics or inhibition on BMP4, SMAD4, osteogenesis-related proteins, ALP activity, and bone mineralization were analyzed in human mesenchymal stromal cells. Luciferase reporter assays were utilized to assay miR-1323’s binding to the 3'UTRs of BMP4 and SMAD4. The effects of miR-1323, BMP4, and SMAD4 were analyzed by siRNA and overexpression vectors. A rat femur fracture model was established to analyze the in vivo effects of antagomiR-1323 treatment. Results miR-1323 was upregulated in human atrophic non-union fractures. Atrophic non-union was associated with downregulation of BMP4 and SMAD4 as well as the osteogenic markers ALP, collagen I, and RUNX2. In vitro, miR-1323 suppressed BMP4 and SMAD4 expression by binding to the 3'UTRs of BMP4 and SMAD4. Moreover, miR-1323’s inhibition of BMP4 and SMAD4 inhibited mesenchymal stromal cell osteogenic differentiation via modulating the nuclear translocation of the transcriptional co-activator TAZ. In vivo, antagomiR-1323 therapy facilitated the healing of fractures in a rat model of femoral fracture. Conclusions This evidence supports the miR-1323/BMP4 and miR-1323/SMAD4 axes as novel therapeutic targets for atrophic non-union fractures.
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Affiliation(s)
- Hui Xie
- Department of Orthopedics, The Second Affiliated Hospital of Jiaxing University, No. 1518 Huanchengbei Road, Jiaxing, Zhejiang, 314299, China
| | - Ming Liu
- Department of Orthopedics, The Second Affiliated Hospital of Jiaxing University, No. 1518 Huanchengbei Road, Jiaxing, Zhejiang, 314299, China
| | - Yaofeng Jin
- Department of Orthopedics, The Second Affiliated Hospital of Jiaxing University, No. 1518 Huanchengbei Road, Jiaxing, Zhejiang, 314299, China
| | - Haiqing Lin
- Department of Orthopedics, The Second Affiliated Hospital of Jiaxing University, No. 1518 Huanchengbei Road, Jiaxing, Zhejiang, 314299, China
| | - Yushan Zhang
- Department of Orthopedics, The Second Affiliated Hospital of Jiaxing University, No. 1518 Huanchengbei Road, Jiaxing, Zhejiang, 314299, China
| | - Song Zheng
- Department of Orthopedics, The Second Affiliated Hospital of Jiaxing University, No. 1518 Huanchengbei Road, Jiaxing, Zhejiang, 314299, China.
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