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Zeng L, He H, Sun M, Gong X, Zhou M, Hong Y, Wu Y, Chen X, Chen Q. Runx2 and Nell-1 in dental follicle progenitor cells regulate bone remodeling and tooth eruption. Stem Cell Res Ther 2022; 13:486. [PMID: 36175952 PMCID: PMC9524038 DOI: 10.1186/s13287-022-03140-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/15/2022] [Indexed: 11/10/2022] Open
Abstract
Dental follicles are necessary for tooth eruption, surround the enamel organ and dental papilla, and regulate both the formation and resorption of alveolar bone. Dental follicle progenitor cells (DFPCs), which are stem cells found in dental follicles, differentiate into different kinds of cells that are necessary for tooth formation and eruption. Runt‐related transcription factor 2 (Runx2) is a transcription factor that is essential for osteoblasts and osteoclasts differentiation, as well as bone remodeling. Mutation of Runx2 causing cleidocranial dysplasia negatively affects osteogenesis and the osteoclastic ability of dental follicles, resulting in tooth eruption difficulties. Among a variety of cells and molecules, Nel-like molecule type 1 (Nell-1) plays an important role in neural crest-derived tissues and is strongly expressed in dental follicles. Nell-1 was originally identified in pathologically fused and fusing sutures of patients with unilateral coronal synostosis, and it plays indispensable roles in bone remodeling, including roles in osteoblast differentiation, bone formation and regeneration, craniofacial skeleton development, and the differentiation of many kinds of stem cells. Runx2 was proven to directly target the Nell-1 gene and regulate its expression. These studies suggested that Runx2/Nell-1 axis may play an important role in the process of tooth eruption by affecting DFPCs. Studies on short and long regulatory noncoding RNAs have revealed the complexity of RNA-mediated regulation of gene expression at the posttranscriptional level. This ceRNA network participates in the regulation of Runx2 and Nell-1 gene expression in a complex way. However, non-study indicated the potential connection between Runx2 and Nell-1, and further researches are still needed.
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Affiliation(s)
- Li Zeng
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Hong He
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, 310006, China.
| | - Mingjie Sun
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Xinyi Gong
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Mengqi Zhou
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Yaya Hong
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Yongjia Wu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Xuepeng Chen
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, 310006, China.
| | - Qianming Chen
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, 310006, China.
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Wang L, Li X, Song Y, Zhang L, Ye L, Zhou X, Song D, Huang D. NELL1 Augments Osteogenesis and Inhibits Inflammation of Human Periodontal Ligament Stem Cells Induced by BMP9. J Periodontol 2021; 93:977-987. [PMID: 34647317 DOI: 10.1002/jper.20-0517] [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: 08/03/2020] [Revised: 09/24/2021] [Accepted: 09/26/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Periodontitis could lead to periodontal destruction such as the loss of alveolar bone. The issue that how to achieve the regeneration of alveolar bone and periodontal tissues under the inflammatory environment needs to be solved urgently. BMP9 is one of the most potent osteo-inductive BMPs and induces osteogenic differentiation of mesenchymal stem cells (MSCs). The aim of this study is to explore the possible effect of BMP9 on the osteogenic differentiation of inflammatory periodontal ligament stem cells (PDLSCs). METHODS Human PDLSCs were cultured in osteo-inductive medium with 1μg/mL lipopolysaccharide Porphyromonas gingivitis (LPS-PG). Adenoviral vector expressing system was used to overexpress target genes. In vitro expression of osteogenic markers was assessed by quantitative reverse transcription PCR, western blotting, alkaline phosphatase assay, and alizarin red staining. Subcutaneous implantation nude mice models were used to evaluate the effects of BMP9 on PDLSCs in vivo. Micro-CT, H&E staining, and trichrome staining were performed to assess ectopic bone formation. RESULTS In the LPS-PG induced inflammatory environment, BMP9 promoted osteogenic differentiation of PDLSCs, but upregulated the expression of inflammatory markers (P>0.05); NELL1 downregulated the expression of inflammation genes in PDLSCs induced by BMP9, while augmenting BMP9 induced osteogenesis of the cells both in vitro and in vivo. In the above process, the MAPK/p38/ERK signaling pathway was triggered by NELL1. CONCLUSION The combination use of BMP9 and NELL1 might have the potential to promote the regeneration of alveolar bone in periodontitis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Liu Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xiangfen Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yao Song
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Lan Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Ling Ye
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Dongzhe Song
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Operative Dentistry and Endodontics West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Dingming Huang
- State Key Laboratory of Oral Diseases & National Clinical Research Center of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.,Department of Operative Dentistry and Endodontics West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Lai K, Xi Y, Du X, Jiang Z, Li Y, Huang T, Miao X, Wang H, Wang Y, Yang G. Activation of Nell-1 in BMSC Sheet Promotes Implant Osseointegration Through Regulating Runx2/Osterix Axis. Front Cell Dev Biol 2020; 8:868. [PMID: 33072736 PMCID: PMC7536315 DOI: 10.3389/fcell.2020.00868] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/11/2020] [Indexed: 12/11/2022] Open
Abstract
Neural epidermal growth factor-like 1 protein (Nell-1) is first studied because of its association with human craniosynostosis. Nell-1 has been used to accelerate the process of fracture healing because of the osteoinductive ability in recent years. However, the role of Nell-1 during the process of osteointegration is unknown. Here we show that activation of Nell-1 in the BMSC sheet promotes osseointegration in vivo and in vitro. We found that overexpression of Nell-1 improved osteogenic differentiation and enhanced matrix mineralization of BMSCs through increasing expression of Runx2 and Osterix. Activation of Nell-1 up-regulated the expression ratio of OPG/RANKL, which might have a negative influence on osteoclast differentiation. Furthermore, we obtained BMSC sheet-implant complexes transfected with lentivirus overexpressing and interfering Nell-1 in in vivo study, and confirmed that overexpression of Nell-1 promoted new bone formation around the implant and increased the bone-implant contacting area percentage. Our results demonstrate that activation of Nell-1 improves implant osteointegration by regulating Runx2/Osterix axis and shows the potential of BMSC sheet-implant complexes in gene therapy.
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Affiliation(s)
- Kaichen Lai
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Yue Xi
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Xue Du
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Zhiwei Jiang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Yongzheng Li
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Tingben Huang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Xiaoyan Miao
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Huiming Wang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Ying Wang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
| | - Guoli Yang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, China
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Wang D, Gilbert JR, Zhang X, Zhao B, Ker DFE, Cooper GM. Calvarial Versus Long Bone: Implications for Tailoring Skeletal Tissue Engineering. TISSUE ENGINEERING PART B-REVIEWS 2019; 26:46-63. [PMID: 31588853 DOI: 10.1089/ten.teb.2018.0353] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tissue-engineered graft substitutes have shown great potential to treat large bone defects. While we usually assume that therapeutic approaches developed for appendicular bone healing could be similarly translated for application in craniofacial reconstruction and vice versa, this is not necessarily accurate. In addition to those more well-known healing-associated factors, such as age, lifestyle (e.g., nutrition and smoking), preexisting disease (e.g., diabetes), medication, and poor blood supply, the developmental origins and surrounding tissue of the wound sites can largely affect the fracture healing outcome as well as designed treatments. Therefore, the strategies developed for long bone fracture repair might not be suitable or directly applicable to skull bone repair. In this review, we discuss aspects of development, healing process, structure, and tissue engineering considerations between calvarial and long bones to assist in designing the tailored bone repair strategies. Impact Statement We summarized, in this review, the existing body of knowledge between long bone and calvarial bone with regard to their development and healing, tissue structure, and consideration of current tissue engineering strategies. By highlighting their similarities and differences, we propose that tailored tissue engineering strategies, such as scaffold features, growth factor usage, and the source of cells for tissue or region-specific bone repair, are necessary to ensure an optimized healing outcome.
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Affiliation(s)
- Dan Wang
- Department of Stomatology, Tenth People's Hospital of Tongji University, Shanghai, China.,Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, China.,School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.,Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - James R Gilbert
- Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,McGowan Institute for Regenerative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Xu Zhang
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, China.,School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Bingkun Zhao
- Department of Stomatology, Tenth People's Hospital of Tongji University, Shanghai, China.,Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, China.,School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Dai Fei Elmer Ker
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, China.,School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Gregory M Cooper
- Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
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Wang B, Wu Y, Yu H, Jiang L, Fang B, Guo Q. The effects of NELL on corticotomy-assisted tooth movement and osteogenesis in a rat model. Biomed Mater Eng 2019; 29:757-771. [PMID: 30282332 DOI: 10.3233/bme-181021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Exogenous Nel-like molecule type 1 (NELL1) represents a potentially attractive clinical treatment option in the orthodontic and other settings because of its osteoinductive and vasculogenic properties. AIMS To explore effects of NELL1on corticotomy-assisted tooth movement and osteogenesis in a rat model. METHODS Thirty Sprague-Dawley rats were divided into 6 groups: Control, Sham, Tooth movement only, Vehicle, NELL1-LD (low-dose NELL), NELL1-HD (high-dose NELL). Human recombinant NELL1 protein was applied locally (Groups NELL1-LD and NELL1-HD) into buccal mucosa region of left first upper molar. Then the distance and velocity of tooth movement was measured, animals at 6 weeks after surgery were sacrificed, and was followed by computed tomography and histochemical staining. RESULTS Both NELL1 groups had higher bone mineral density, greater tooth movement distance and velocity in comparison to the Vehicle group. Proximally and distally, periodontal ligament width was significantly increased in the NELL1-LD and NELL1-HD groups. Decortication enhances remodeling, however, rapid bone formation by high-dose NELL1 may affect bone absorption. CONCLUSION Appropriate dose of NELL1 can be administrated to reduce the total time for tooth movement, and may shorten the treatment time in select populations.
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Affiliation(s)
- Bo Wang
- Department of Oral and Craniomaxillofacial Science, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China
| | - Yong Wu
- Department of Oral and Craniomaxillofacial Science, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China
| | - Hongbo Yu
- Department of Oral and Craniomaxillofacial Science, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China
| | - Lingyong Jiang
- Department of Oral and Craniomaxillofacial Science, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China
| | - Bing Fang
- Department of Oral and Craniomaxillofacial Science, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China
| | - Qiuman Guo
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China
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Pakvasa M, Alverdy A, Mostafa S, Wang E, Fu L, Li A, Oliveira L, Athiviraham A, Lee MJ, Wolf JM, He TC, Ameer GA, Reid RR. Neural EGF-like protein 1 (NELL-1): Signaling crosstalk in mesenchymal stem cells and applications in regenerative medicine. Genes Dis 2017; 4:127-137. [PMID: 29276737 PMCID: PMC5737940 DOI: 10.1016/j.gendis.2017.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 12/15/2022] Open
Abstract
Bone tissue regeneration holds the potential to solve both osteoporosis and large skeletal defects, two problems associated with significant morbidity. The differentiation of mesenchymal stem cells into the osteogenic lineage requires a specific microenvironment and certain osteogenic growth factors. Neural EGF Like-Like molecule 1 (NELL-1) is a secreted glycoprotein that has proven, both in vitro and in vivo, to be a potent osteo-inductive factor. Furthermore, it has been shown to repress adipogenic differentiation and inflammation. NELL-1 can work synergistically with other osteogenic factors such as Bone Morphogenic Protein (BMP) -2 and -9, and has shown promise for use in tissue engineering and as a systemically administered drug for the treatment of osteoporosis. Here we provide a comprehensive up-to-date review on the molecular signaling cascade of NELL-1 in mesenchymal stem cells and potential applications in bone regenerative engineering.
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Affiliation(s)
- Mikhail Pakvasa
- The University of Chicago, Pritzker School of Medicine, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Section of Plastic and Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Alex Alverdy
- Laboratory of Craniofacial Biology and Development, Section of Plastic and Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Rosalind Franklin University, Chicago Medical School, North Chicago, IL 60064, USA
| | - Sami Mostafa
- The University of Chicago, Pritzker School of Medicine, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Section of Plastic and Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Eric Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Lucy Fu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Alexander Li
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Leonardo Oliveira
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Aravind Athiviraham
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Michael J. Lee
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Jennifer Moriatis Wolf
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Tong-Chuan He
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Guillermo A. Ameer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Advanced Regenerative Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Russell R. Reid
- The University of Chicago, Pritzker School of Medicine, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Section of Plastic and Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
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Liu M, Wang Q, Tang R, Cao R, Wang X. Nel-like Molecule 1 Contributes to the Odontoblastic Differentiation of Human Dental Pulp Cells. J Endod 2016; 42:95-100. [DOI: 10.1016/j.joen.2015.08.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 08/16/2015] [Accepted: 08/27/2015] [Indexed: 10/22/2022]
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Lee YJ, Park SY, Lee SJ, Boo YC, Choi JY, Kim JE. Ucma, a direct transcriptional target of Runx2 and Osterix, promotes osteoblast differentiation and nodule formation. Osteoarthritis Cartilage 2015; 23:1421-31. [PMID: 25865393 DOI: 10.1016/j.joca.2015.03.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 03/23/2015] [Accepted: 03/28/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Runt-related transcription factor 2 (Runx2) and Osterix (Osx) are the master transcription factors in bone formation. Nonetheless, genes acting downstream of both Runx2 and Osx have yet to be fully characterized. Here, we investigate the downstream targets of both Runx2 and Osx in osteoblasts. MATERIALS AND METHODS DNA microarray analysis was conducted on calvarial RNA from wild-type, Runx2 heterozygous, Osx heterozygous, and Runx2/Osx double heterozygous embryos. Expression and transcriptional responses of the selected target gene were analyzed in MC3T3-E1 osteoblastic cells. RESULTS The expression of unique cartilage matrix-associated protein (Ucma) was decreased in Runx2/Osx double heterozygous embryos. In contrast, Ucma expression was increased in osteoblasts overexpressing both Runx2 and Osx. Ucma expression was initiated mid-way through osteoblast differentiation and continued throughout the differentiation process. Transcriptional activity of the Ucma promoter was increased upon transfection of the cells with both Runx2 and Osx. Runx2-and Osx-mediated activation of the Ucma promoter was directly regulated by Runx2-and/or Sp1-binding sites within its promoter. During osteoblast differentiation, the formation of mineralized nodules in Ucma-overexpressing stable clones occurred earlier and was more enhanced than that in the mock-transfected control. Mineralized nodule formation was strongly augmented in the cells cultured in a medium containing secretory Ucma proteins. CONCLUSION Ucma is a novel downstream gene regulated by both Runx2 and Osx and it stimulates osteoblast differentiation and nodule formation.
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Affiliation(s)
- Y-J Lee
- Cell and Matrix Research Institute, Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Republic of Korea.
| | - S-Y Park
- Department of Biochemistry, School of Medicine, Dongguk University, Gyeongju, Republic of Korea.
| | - S-J Lee
- Cell and Matrix Research Institute, Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Republic of Korea.
| | - Y C Boo
- Cell and Matrix Research Institute, Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Republic of Korea.
| | - J-Y Choi
- Cell and Matrix Research Institute, Department of Biochemistry and Cell Biology, Kyungpook National University School of Medicine, Daegu, Republic of Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Republic of Korea.
| | - J-E Kim
- Cell and Matrix Research Institute, Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Republic of Korea.
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Artigas N, Ureña C, Rodríguez-Carballo E, Rosa JL, Ventura F. Mitogen-activated protein kinase (MAPK)-regulated interactions between Osterix and Runx2 are critical for the transcriptional osteogenic program. J Biol Chem 2014; 289:27105-27117. [PMID: 25122769 PMCID: PMC4175347 DOI: 10.1074/jbc.m114.576793] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 08/06/2014] [Indexed: 11/06/2022] Open
Abstract
The transcription factors Runx2 and Osx (Osterix) are required for osteoblast differentiation and bone formation. Runx2 expression occurs at early stages of osteochondroprogenitor determination, followed by Osx induction during osteoblast maturation. We demonstrate that coexpression of Osx and Runx2 leads to cooperative induction of expression of the osteogenic genes Col1a1, Fmod, and Ibsp. Functional interaction of Osx and Runx2 in the regulation of these promoters is mediated by enhancer regions with adjacent Sp1 and Runx2 DNA-binding sites. These enhancers allow formation of a cooperative transcriptional complex, mediated by the binding of Osx and Runx2 to their specific DNA promoter sequences and by the protein-protein interactions between them. We also identified the domains involved in the interaction between Osx and Runx2. These regions contain the amino acids in Osx and Runx2 known to be phosphorylated by p38 and ERK MAPKs. Inhibition of p38 and ERK kinase activities or mutation of their known phosphorylation sites in Osx or Runx2 strongly disrupts their physical interaction and cooperative transcriptional effects. Altogether, our results provide a molecular description of a mechanism for Osx and Runx2 transcriptional cooperation that is subject to further regulation by MAPK-activating signals during osteogenesis.
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Affiliation(s)
- Natalia Artigas
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, L'Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), E-08907 L'Hospitalet de Llobregat, Spain
| | - Carlos Ureña
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, L'Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), E-08907 L'Hospitalet de Llobregat, Spain
| | - Edgardo Rodríguez-Carballo
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, L'Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), E-08907 L'Hospitalet de Llobregat, Spain
| | - José Luis Rosa
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, L'Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), E-08907 L'Hospitalet de Llobregat, Spain
| | - Francesc Ventura
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, L'Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), E-08907 L'Hospitalet de Llobregat, Spain.
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10
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Bone microstructure and regional distribution of osteoblast and osteoclast activity in the osteonecrotic femoral head. PLoS One 2014; 9:e96361. [PMID: 24800992 PMCID: PMC4011745 DOI: 10.1371/journal.pone.0096361] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 04/06/2014] [Indexed: 12/31/2022] Open
Abstract
Objective To detect and compare the bone microstructure and osteoblast and osteoclast activity in different regions of human osteonecrotic femoral heads. Methods Osteonecrotic femoral heads were obtained from 10 patients (6 males, 4 females; Ficat IV) undergoing total hip arthroplasty between 2011 and 2013. The samples were divided into subchondral bone, necrotic, sclerotic, and healthy regions based on micro-computed tomography (CT) images. The bone microstructure, micromechanics, and osteoblast and osteoclast activity were assessed using micro-CT, pathology, immunohistochemistry, nanoindentation, reverse transcription polymerase chain reaction (RT-PCR), tartrate-resistant acid phosphatase staining and Western blotting. Results (1) The spatial structure of the bone trabeculae differed markedly in the various regions of the osteonecrotic femoral heads. (2) The elastic modulus and hardness of the bone trabeculae in the healthy and necrotic regions did not differ significantly (P >0.05). (3) The subchondral bone and necrotic region were positive on TRAP staining, while the other regions were negative. (4) On immunohistochemical staining, RANK and RANKL staining intensities were increased significantly in the subchondral bone and necrotic region compared with the healthy region, while RUNX2 and BMP2 staining intensities were increased significantly in the sclerotic region compared with the necrotic region. (5) OPG, RANK, RANKL, RUNX2, BMP2, and BMP7 protein levels were greater in the necrotic and sclerotic region than in subchondral bone and the healthy region. Conclusion The micromechanical properties of bone trabeculae in the necrotic region did not differ significantly from the healthy region. During the progress of osteonecrosis, the bone structure changed markedly. Osteoclast activity increased in subchondral bone and the necrotic region while osteoblast activity increased in the sclerotic region. We speculate that the altered osteoblast and osteoclast activity leads to a reduction in macroscopic mechanical strength.
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Fan WL, Ng CS, Chen CF, Lu MYJ, Chen YH, Liu CJ, Wu SM, Chen CK, Chen JJ, Mao CT, Lai YT, Lo WS, Chang WH, Li WH. Genome-wide patterns of genetic variation in two domestic chickens. Genome Biol Evol 2013; 5:1376-92. [PMID: 23814129 PMCID: PMC3730349 DOI: 10.1093/gbe/evt097] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Domestic chickens are excellent models for investigating the genetic basis of phenotypic diversity, as numerous phenotypic changes in physiology, morphology, and behavior in chickens have been artificially selected. Genomic study is required to study genome-wide patterns of DNA variation for dissecting the genetic basis of phenotypic traits. We sequenced the genomes of the Silkie and the Taiwanese native chicken L2 at ∼23- and 25-fold average coverage depth, respectively, using Illumina sequencing. The reads were mapped onto the chicken reference genome (including 5.1% Ns) to 92.32% genome coverage for the two breeds. Using a stringent filter, we identified ∼7.6 million single-nucleotide polymorphisms (SNPs) and 8,839 copy number variations (CNVs) in the mapped regions; 42% of the SNPs have not found in other chickens before. Among the 68,906 SNPs annotated in the chicken sequence assembly, 27,852 were nonsynonymous SNPs located in 13,537 genes. We also identified hundreds of shared and divergent structural and copy number variants in intronic and intergenic regions and in coding regions in the two breeds. Functional enrichments of identified genetic variants were discussed. Radical nsSNP-containing immunity genes were enriched in the QTL regions associated with some economic traits for both breeds. Moreover, genetic changes involved in selective sweeps were detected. From the selective sweeps identified in our two breeds, several genes associated with growth, appetite, and metabolic regulation were identified. Our study provides a framework for genetic and genomic research of domestic chickens and facilitates the domestic chicken as an avian model for genomic, biomedical, and evolutionary studies.
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Affiliation(s)
- Wen-Lang Fan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
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Lee HS, Lee J, Kim SO, Song JS, Lee JH, Lee SI, Jung HS, Choi BJ. Comparative gene-expression analysis of the dental follicle and periodontal ligament in humans. PLoS One 2013; 8:e84201. [PMID: 24376796 PMCID: PMC3871683 DOI: 10.1371/journal.pone.0084201] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/13/2013] [Indexed: 01/18/2023] Open
Abstract
The human dental follicle partially differentiates into the periodontal ligament (PDL), but their biological functions are different. The gene-expression profiles of the dental follicle and PDL were compared using the cDNA microarray technique. Microarray analysis identified 490 genes with a twofold or greater difference in expression, 365 and 125 of which were more abundant in the dental follicle and PDL, respectively. The most strongly expressed genes in the dental follicle were those related to bone development and remodeling (EGFL6, MMP8, FRZB, and NELL1), apoptosis and chemotaxis (Nox4, CXCL13, and CCL2), and tooth and embryo development (WNT2, PAX3, FGF7, AMBN, AMTN, and SLC4A4), while in the PDL it was the tumor-suppressor gene WIF1. Genes related to bone development and remodeling (STMN2, IBSP, BMP8A, BGLAP, ACP5, OPN, BMP3, and TM7SF4) and wound healing (IL1, IL8, MMP3, and MMP9) were also more strongly expressed in the PDL than in the dental follicle. In selected genes, a comparison among cDNA microarray, real-time reverse-transcription polymerase chain reaction, and immunohistochemical staining confirmed similar relative gene expressions. The gene-expression profiles presented here identify candidate genes that may enable differentiation between the dental follicle and PDL.
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Affiliation(s)
- Hyo-Seol Lee
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Jongeun Lee
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Seong-Oh Kim
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Je-Seon Song
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Jae-Ho Lee
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Syng-Ill Lee
- Division in Oral Physiology, Department of Oral Biology, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Han-Sung Jung
- Division in Anatomy & Developmental Biology, Department of Oral Biology, College of Dentistry, Yonsei University, Seoul, Republic of Korea
| | - Byung-Jai Choi
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea
- * E-mail:
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Turner NJ, Londono R, Dearth CL, Culiat CT, Badylak SF. Human NELL1 protein augments constructive tissue remodeling with biologic scaffolds. Cells Tissues Organs 2013; 198:249-65. [PMID: 24335144 DOI: 10.1159/000356491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2013] [Indexed: 11/19/2022] Open
Abstract
Biologic scaffolds composed of extracellular matrix (ECM) derived from decellularized tissues effectively reprogram key stages of the mammalian response to injury, altering the wound microenvironment from one that promotes scar tissue formation to one that stimulates constructive and functional tissue remodeling. In contrast, engineered scaffolds, composed of purified ECM components such as collagen, lack the complex ultrastructure and composition of intact ECM and may promote wound healing but lack factors that facilitate constructive and functional tissue remodeling. The objective of the present study was to test the hypothesis that addition of NELL1, a signaling protein that controls cell growth and differentiation, enhances the constructive tissue remodeling of a purified collagen scaffold. An abdominal wall defect model in the rat of 1.5-cm(2) partial thickness was used to compare the constructive remodeling of a bovine type I collagen scaffold to a biologic scaffold derived from small intestinal submucosa (SIS)-ECM with and without augmentation with 17 μg NELL1 protein. Samples were evaluated histologically at 14 days and 4 months. The contractile response of the defect site was also evaluated at 4 months. Addition of NELL1 protein improved the constructive remodeling of collagen scaffolds but not SIS-ECM scaffolds. Results showed an increase in the contractile force of the remodeled skeletal muscle and a fast:slow muscle composition similar to native tissue in the collagen-treated group. The already robust remodeling response to SIS-ECM was not enhanced by NELL1 at the dose tested. These findings suggest that NELL1 protein does contribute to the enhanced constructive remodeling of skeletal muscle.
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Affiliation(s)
- Neill J Turner
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa., USA
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Recent progresses in gene delivery-based bone tissue engineering. Biotechnol Adv 2013; 31:1695-706. [DOI: 10.1016/j.biotechadv.2013.08.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/24/2013] [Accepted: 08/19/2013] [Indexed: 12/18/2022]
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Gadi J, Jung SH, Lee MJ, Jami A, Ruthala K, Kim KM, Cho NH, Jung HS, Kim CH, Lim SK. The transcription factor protein Sox11 enhances early osteoblast differentiation by facilitating proliferation and the survival of mesenchymal and osteoblast progenitors. J Biol Chem 2013; 288:25400-25413. [PMID: 23888050 DOI: 10.1074/jbc.m112.413377] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sox11 deletion mice are known to exhibit developmental defects of craniofacial skeletal malformations, asplenia, and hypoplasia of the lung, stomach, and pancreas. Despite the importance of Sox11 in the developing skeleton, the role of Sox11 in osteogenesis has not been studied yet. In this study, we identified that Sox11 is an important transcription factor for regulating the proliferation and survival of osteoblast precursor cells as well as the self-renewal potency of mesenchymal progenitor cells via up-regulation of Tead2. Furthermore, Sox11 also plays an important role in the segregation of functional osteoblast lineage progenitors from osteochondrogenic progenitors. Facilitation of osteoblast differentiation from mesenchymal cells was achieved by enhanced expression of the osteoblast lineage specific transcription factors Runx2 and Osterix. Morpholino-targeted disruption of Sox11 in zebrafish impaired organogenesis, including the bones, which were under mineralized. These results indicated that Sox11 plays a crucial role in the proliferation and survival of mesenchymal and osteoblast precursors by Tead2, and osteogenic differentiation by regulating Runx2 and Osterix.
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Affiliation(s)
- Jogeswar Gadi
- From the Division of Endocrinology and Endocrine Research Institute, Department of Internal Medicine
| | - Seung-Hyun Jung
- the Diabetic Complications Research Center, Division of Traditional Korean Medicine (TKM), Integrated Research, Korea Institute of Oriental Medicine (KIOM), Daejeon, Korea 305-811; the Laboratory of Developmental Genetics, Department of Biology, Chungnam National University, Daejeon, Korea 305-764
| | - Min-Jung Lee
- the Brain Korea 21 Project for Medical Sciences,; the Division of Anatomy and Developmental Biology, Department of Oral Biology, Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Korea 120-752, and
| | - Ajita Jami
- From the Division of Endocrinology and Endocrine Research Institute, Department of Internal Medicine,; the Brain Korea 21 Project for Medical Sciences
| | - Kalyani Ruthala
- the Brain Korea 21 Project for Medical Sciences,; the Department of Anatomy, Embryology Lab, Yonsei University College of Medicine, Seoul, Korea 120-752
| | - Kyoung-Min Kim
- From the Division of Endocrinology and Endocrine Research Institute, Department of Internal Medicine,; the Brain Korea 21 Project for Medical Sciences
| | | | - Han-Sung Jung
- the Division of Anatomy and Developmental Biology, Department of Oral Biology, Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Korea 120-752, and
| | - Cheol-Hee Kim
- the Laboratory of Developmental Genetics, Department of Biology, Chungnam National University, Daejeon, Korea 305-764
| | - Sung-Kil Lim
- From the Division of Endocrinology and Endocrine Research Institute, Department of Internal Medicine,; the Brain Korea 21 Project for Medical Sciences,.
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Liu Y, Chen C, He H, Wang D, E L, Liu Z, Liu H. Lentiviral-mediated gene transfer into human adipose-derived stem cells: role of NELL1 versus BMP2 in osteogenesis and adipogenesis in vitro. Acta Biochim Biophys Sin (Shanghai) 2012; 44:856-65. [PMID: 23017834 DOI: 10.1093/abbs/gms070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
NEL-like molecule 1 (NELL1) is a potent osteogenic factor associated with craniosynostosis. Adenoviruses, the most commonly used viral vectors for gene therapy, have several disadvantages that may restrict osteogenesis. Previous studies have shown that lentiviruses can serve as ideal vectors for gene therapy for bone regeneration. In this study, two lentiviral vectors (LvNELL1 and LvBMP2) that encode human NELL1 and bone morphogenetic protein-2 (BMP2), respectively, were constructed. The effect of LvNELL1 infection on the proliferation, osteogenesis, and adipogenesis of human adipose-derived stem cells (hADSCs) in vitro was assessed and compared with that of LvBMP2. The results showed that hADSCs infected with LvNELL1 could efficiently and stably overexpress the target genes. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results demonstrated that LvBMP2, but not LvNELL1, enhanced the proliferation of hADSCs. Assessment of alkaline phosphatase activity and cellular mineralization indicated that LvNELL1 infection promoted the osteogenic differentiation of hADSCs, and the effect was comparable with that of LvBMP2. Real-time polymerase chain reaction (PCR) revealed that LvNELL1 infection upregulated OSX expression but not RUNX2 expression in hADSCs. In addition, adipogenic markers (lipid droplets, peroxisome proliferator-activating receptor γ, and lipoprotein lipase) analysis showed that LvNELL1 could dramatically inhibit the adipogenic differentiation of hADSCs, but LvBMP2 had no such effect. Taken together, these findings suggested that lentiviral-mediated NELL1 gene transfer in hADSCs may be a novel and promising approach to achieve effective and precise bone regeneration.
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Affiliation(s)
- Yajing Liu
- Institute of Stomatology, Chinese PLA General Hospital, Beijing, China
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NELL-1-dependent mineralisation of Saos-2 human osteosarcoma cells is mediated via c-Jun N-terminal kinase pathway activation. INTERNATIONAL ORTHOPAEDICS 2012; 36:2181-7. [PMID: 22797704 DOI: 10.1007/s00264-012-1590-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 05/22/2012] [Indexed: 12/22/2022]
Abstract
PURPOSE NELL-1 is a novel osteoinductive growth factor that has shown promising results for the regeneration of bone. Moreover, NELL-1 has been used successfully in bone regeneration in the axial, appendicular and calvarial skeleton of both small and large animal models. Despite increasing evidence of NELL-1 efficacy and future usefulness as an alternative to traditional bone graft substitutes, much has yet to be understood regarding the mechanisms of action of this novel protein. The activation of the mitogen-activated protein kinase (MAPK) pathway has been well studied in the setting of growth factor-mediated changes in osteogenic differentiation. METHODS In this study, we provide evidence of the involvement of MAPK signalling pathways in NELL-1-induced terminal osteogenic differentiation of Saos-2 human osteosarcoma cells. Activation of extracellular signal-regulated kinase (ERK1/2), P38 and c-Jun N-terminal kinase (JNK) pathways were screened with MAPK signalling protein array after recombinant human (rh)NELL-1 treatment. Next, the mineralisation and intracellular phosphate levels after rhNELL-1 stimulation were assessed in the presence or absence of specific MAPK inhibitors. RESULTS Results showed that rhNELL-1 predominantly increased JNK pathway activation. Moreover, the specific JNK inhibitor SP600125 blocked rhNELL-1-induced mineralisation and intracellular phosphate accumulation, whereas ERK1/2 and P38 inhibitors showed no effect. CONCLUSIONS Thus, activation of the JNK pathway is necessary to mediate terminal osteogenic differentiation of Saos-2 osteosarcoma cells by rhNELL-1. Future studies will extend these in vitro mechanisms to the in vivo effects of NELL-1 in dealing with orthopaedic defects caused by skeletal malignancies or other aetiologies.
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