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Saghati S, Avci ÇB, Hassani A, Nazifkerdar S, Amini H, Saghebasl S, Mahdipour M, Banimohamad-Shotorbani B, Namjoo AR, Abrbekoh FN, Rahbarghazi R, Nasrabadi HT, Khoshfetrat AB. Phenolated alginate hydrogel induced osteogenic properties of mesenchymal stem cells via Wnt signaling pathway. Int J Biol Macromol 2023; 253:127209. [PMID: 37804896 DOI: 10.1016/j.ijbiomac.2023.127209] [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: 08/20/2022] [Revised: 09/06/2023] [Accepted: 10/01/2023] [Indexed: 10/09/2023]
Abstract
Osteogenic properties of phenolated alginate (1.2 %) hydrogel containing collagen (0.5 %)/nano-hydroxyapatite (1 %) were studied on human mesenchymal stem cells in vitro. The phenolation rate and physical properties of the hydrogel were assessed using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), swelling ratio, gelation time, mechanical assay, and degradation rate. The viability of encapsulated cells was monitored on days 7, 14, and 21 using an MTT assay. Osteoblast differentiation was studied using western blotting, and real-time PCR. Using PCR array analysis, the role of the Wnt signaling pathway was also investigated. Data showed that the combination of alginate/collagen/nanohydroxyapatite yielded proper mechanical features. The addition of nanohydroxyapatite, and collagen reduced degradation, swelling rate coincided with increased stiffness. Elasticity and pore size were also diminished. NMR and FTIR revealed suitable incorporation of collagen and nanohydroxyapatite in the structure of alginate. Real-time PCR analysis and western blotting indicated the expression of osteoblast-related genes such as Runx2 and osteocalcin. PCR array revealed the induction of numerous genes related to Wnt signaling pathways during the maturation of human stem cells toward osteoblast-like cells. In vivo data indicated that transplantation of phenolated alginate/collagen/nanohydroxyapatite hydrogel led to enhanced de novo bone formation in rats with critical-sized calvarial defects. Phenolated alginate hydrogel can promote the osteogenic capacity of human amniotic membrane mesenchymal stem cells in the presence of nanohydroxyapatite and collagen via engaging the Wnt signaling pathway.
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Affiliation(s)
- Sepideh Saghati
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Tissue Engineering, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Çığır Biray Avci
- Department of Medical Biology, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Ayla Hassani
- Chemical Engineering Faculty, Sahand University of Technology, Tabriz 51335-1996, Iran; Stem Cell and Tissue Engineering Research Laboratory, Sahand University of Technology, Tabriz 51335-1996, Iran
| | - Sajed Nazifkerdar
- Chemical Engineering Faculty, Sahand University of Technology, Tabriz 51335-1996, Iran; Stem Cell and Tissue Engineering Research Laboratory, Sahand University of Technology, Tabriz 51335-1996, Iran
| | - Hassan Amini
- Department of General and Vascular Surgery, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Solmaz Saghebasl
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahdi Mahdipour
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behnaz Banimohamad-Shotorbani
- Department of Tissue Engineering, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Atieh Rezaei Namjoo
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Reza Rahbarghazi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Applied Cell Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Hamid Tayefi Nasrabadi
- Department of Tissue Engineering, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Ali Baradar Khoshfetrat
- Department of Medical Biology, Faculty of Medicine, Ege University, Izmir, Turkey; Chemical Engineering Faculty, Sahand University of Technology, Tabriz 51335-1996, Iran.
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2
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Gordon JAR, Tye CE, Banerjee B, Ghule PN, van Wijnen AJ, Kabala FS, Page NA, Falcone MM, Stein JL, Stein GS, Lian JB. LINC01638 sustains human mesenchymal stem cell self-renewal and competency for osteogenic cell fate. Sci Rep 2023; 13:20314. [PMID: 37985890 PMCID: PMC10662126 DOI: 10.1038/s41598-023-46202-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/29/2023] [Indexed: 11/22/2023] Open
Abstract
The skeleton forms from multipotent human mesenchymal stem cells (hMSCs) competent to commit to specific lineages. Long noncoding RNAs (lncRNAs) have been identified as key epigenetic regulators of tissue development. However, regulation of osteogenesis by lncRNAs as mediators of commitment to the bone phenotype is largely unexplored. We focused on LINC01638, which is highly expressed in hMSCs and has been studied in cancers, but not in regulating osteogenesis. We demonstrated that LINC01638 promotes initiation of the osteoblast phenotype. Our findings reveal that LINC01638 is present at low levels during the induction of osteoblast differentiation. CRISPRi knockdown of LINC01638 in MSCs prevents osteogenesis and alkaline phosphatase expression, inhibiting osteoblast differentiation. This resulted in decreased MSC growth rate, accompanied by double-strand breaks, DNA damage, and cell senescence. Transcriptome profiling of control and LINC01638-depleted hMSCs identified > 2000 differentially expressed mRNAs related to cell cycle, cell division, spindle formation, DNA repair, and osteogenesis. Using ChIRP-qPCR, molecular mechanisms of chromatin interactions revealed the LINC01638 locus (Chr 22) includes many lncRNAs and bone-related genes. These novel findings identify the obligatory role for LINC01638 to sustain MSC pluripotency regulating osteoblast commitment and growth, as well as for physiological remodeling of bone tissue.
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Affiliation(s)
- Jonathan A R Gordon
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
- University of Vermont Cancer Center, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA
| | - Coralee E Tye
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
- University of Vermont Cancer Center, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA
| | | | - Prachi N Ghule
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
- University of Vermont Cancer Center, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA
| | - Andre J van Wijnen
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
| | - Fleur S Kabala
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
| | - Natalie A Page
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
| | - Michelle M Falcone
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
| | - Janet L Stein
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
- University of Vermont Cancer Center, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA
| | - Gary S Stein
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA
- University of Vermont Cancer Center, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA
| | - Jane B Lian
- Department of Biochemistry, University of Vermont, Burlington, VT, 05405, USA.
- University of Vermont Cancer Center, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA.
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3
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Yang L, Yergeshov AA, Al-Thaher Y, Avdokushina S, Statsenko E, Abdullin TI, Prokopovich P. Nanocomposite orthopaedic bone cement combining long-acting dual antimicrobial drugs. BIOMATERIALS ADVANCES 2023; 153:213538. [PMID: 37390562 PMCID: PMC10824671 DOI: 10.1016/j.bioadv.2023.213538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/22/2023] [Accepted: 06/22/2023] [Indexed: 07/02/2023]
Abstract
Antibiotic loaded bone cements are widely used in total joint replacement (TJR); despite many limitations such as a burst release which leads to antibiotic concentration below inhibitory levels and possibly contributing to the selection of antibiotic resistant strains. In order to address such limitations and to simultaneously address antibiotic resistance and short-term antimicrobial activity, we developed a nanocomposite bone cement capable of providing a controlled release of antimicrobial agents from bone cement to act as prophylaxis or treatment against prosthetic joint infections (PJIs). Gentamicin and chlorhexidine were loaded in combination on silica nanoparticles surface using layer-by-layer coating technique (LbL) combining hydrolysable and non-hydrolysable polymers. The drug release from the nanocomposite continued for >50 days at concentrations higher than the commercial formulation containing the same amount of antimicrobial drugs, where burst release for few days were observed. Moreover, the nanocomposite bone cement showed superior antimicrobial inhibition without adversely affecting the mechanical properties or the ability of osteoblasts to grow. In vivo experiments with an infected bone lesion model along with mass-spectrometric analysis also provided further evidence of efficacy and safety of the implanted nanocomposite material as well as its prolonged drug eluting profile. The developed nanocomposite bone cement has the potential to reduce PJIs and enable treatment of resistant established infections; moreover, the newly developed LbL based nano-delivery system may also have wider applications in reducing the threat posed by antimicrobial resistance.
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Affiliation(s)
- Lirong Yang
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | - Abdulla A Yergeshov
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia
| | - Yazan Al-Thaher
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | - Svetlana Avdokushina
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia
| | - Evgeny Statsenko
- Institute of Geology and Petroleum Technologies, 4/5 Kremlyovskaya St., 420111 Kazan, Russia
| | - Timur I Abdullin
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia
| | - Polina Prokopovich
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK.
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4
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Gordon J, Tye CE, Banerjee B, Ghule PN, Wijnen AJ, Kabala FS, Page NA, Falcone MM, Stein JL, Stein GS, Lian JB. LINC01638 Sustains Human Mesenchymal Stem Cell Self-Renewal and Competency for Osteogenic Cell Fate. RESEARCH SQUARE 2023:rs.3.rs-3210911. [PMID: 37693373 PMCID: PMC10491330 DOI: 10.21203/rs.3.rs-3210911/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The skeleton forms from multipotent human mesenchymal stem cells (hMSCs) competent to commit to specific lineages. Long noncoding RNAs (lncRNAs) have been identified as key epigenetic regulators of tissue development. However, regulation of osteogenesis by lncRNAs as mediators of commitment to the bone phenotype is largely unexplored. We focused on LINC01638, which is highly expressed in hMSCs and has been studied in cancers, but not in regulating osteogenesis. We demonstrated that LINC01638 promotes initiation of the osteoblast phenotype. Our findings reveal that LINC01638 is present at low levels during the induction of osteoblast differentiation. CRISPRi knockdown of LINC01638 in MSCs prevents osteogenesis and alkaline phosphatase expression, inhibiting osteoblast differentiation. This resulted in decreased MSC cell growth rate, accompanied by double-strand breaks, DNA damage, and cell senescence. Transcriptome profiling of control and LINC01638-depleted hMSCs identified > 2,000 differentially expressed mRNAs related to cell cycle, cell division, spindle formation, DNA repair, and osteogenesis. Using ChIRP-qPCR, molecular mechanisms of chromatin interactions revealed the LINC01638 locus (Chr 22) includes many lncRNAs and bone-related genes. These novel findings identify the obligatory role for LINC01638 to sustain MSC pluripotency regulating osteoblast commitment and growth, as well as for physiological remodeling of bone tissue.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Gary S Stein
- University of Vermont, Larner College of Medicine
| | - Jane B Lian
- University of Vermont, Larner College of Medicine
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5
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Sun Y, Gao Y, Dong M, Li J, Li X, He N, Song H, Zhang M, Ji K, Wang J, Gu Y, Wang Y, Du L, Liu Y, Wang Q, Zhai H, Sun D, Liu Q, Xu C. Kremen2 drives the progression of non-small cell lung cancer by preventing SOCS3-mediated degradation of EGFR. J Exp Clin Cancer Res 2023; 42:140. [PMID: 37270563 DOI: 10.1186/s13046-023-02692-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 04/28/2023] [Indexed: 06/05/2023] Open
Abstract
BACKGROUND The transmembrane receptor Kremen2 has been reported to participate in the tumorigenesis and metastasis of gastric cancer. However, the role of Kremen2 in non-small cell lung cancer (NSCLC) and the underlying mechanism remain unclear. This study aimed to explore the biological function and regulatory mechanism of Kremen2 in NSCLC. METHODS The correlation between Kremen2 expression and NSCLC was assessed by analyzing the public database and clinical tissue samples. Colony formation and EdU assays were performed to examine cell proliferation. Transwell and wound healing assays were used to observe cell migration ability. Tumor-bearing nude mice and metastatic tumor models were used to detect the in vivo tumorigenic and metastatic abilities of the NSCLC cells. An immunohistochemical assay was used to detect the expression of proliferation-related proteins in tissues. Western blot, immunoprecipitation and immunofluorescence were conducted to elucidate the Kremen2 regulatory mechanisms in NSCLC. RESULTS Kremen2 was highly expressed in tumor tissues from NSCLC patients and was positively correlated with a poor patient prognosis. Knockout or knockdown of Kremen2 inhibited cell proliferation and migration ability of NSCLC cells. In vivo knockdown of Kremen2 inhibited the tumorigenicity and number of metastatic nodules of NSCLC cells in nude mice. Mechanistically, Kremen2 interacted with suppressor of cytokine signaling 3 (SOCS3) to maintain the epidermal growth factor receptor (EGFR) protein levels by preventing SOCS3-mediated ubiquitination and degradation of EGFR, which, in turn, promoted activation of the PI3K-AKT and JAK2-STAT3 signaling pathways. CONCLUSIONS Our study identified Kremen2 as a candidate oncogene in NSCLC and may provide a potential target for NSCLC treatment.
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Affiliation(s)
- Yuxiao Sun
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Yu Gao
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Mingxin Dong
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Jiuzhen Li
- Graduate School, Tianjin Medical University, Tianjin, 300070, China
- Department of Thoracic Surgery, Tianjin Chest Hospital of Tianjin University, Tianjin, 300222, China
| | - Xin Li
- Graduate School, Tianjin Medical University, Tianjin, 300070, China
- Department of Thoracic Surgery, Tianjin Chest Hospital of Tianjin University, Tianjin, 300222, China
| | - Ningning He
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Huijuan Song
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Manman Zhang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Kaihua Ji
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Jinhan Wang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Yeqing Gu
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Yan Wang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Liqing Du
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Yang Liu
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Qin Wang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
| | - Hezheng Zhai
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China
- School of Precision Instruments and OPTO-Electronics Engineering, Tianjin University, Tianjin, 300072, China
| | - Daqiang Sun
- Graduate School, Tianjin Medical University, Tianjin, 300070, China.
- Department of Thoracic Surgery, Tianjin Chest Hospital of Tianjin University, Tianjin, 300222, China.
| | - Qiang Liu
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China.
| | - Chang Xu
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, 300192, China.
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Long J, Cong F, Wei Y, Liu J, Tang W. Increased Kremen2 predicts worse prognosis in colon cancer. Pathol Oncol Res 2023; 29:1611082. [PMID: 37123533 PMCID: PMC10130194 DOI: 10.3389/pore.2023.1611082] [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: 01/28/2023] [Accepted: 04/03/2023] [Indexed: 05/02/2023]
Abstract
Background: Colon cancer (CC) is the fifth most prevalent cancer around the globe and poses a major risk to human health. Even though Kremen2 serves as a prognostic indicator in individuals with malignant tumours, its role in evaluating the prognosis of individuals with colon cancer has not been confirmed. Methods: Here, we examined the protein expression of Kremen2 in CC tissues and paired adjacent normal tissues by immunohistochemistry (IHC), then analyzed the clinical and RNA-seq data presented in The Cancer Genome Atlas (TCGA) database to confirm the relationship between Kremen2 levels and CC. In addition, the associations between Kremen2 mRNA expression and infiltrating immune cells were examined. Results: The study showed that the mRNA expression and protein level of Kremen2 were increased in CC tissues compared with adjacent normal tissues. According to Kaplan-Meier analysis, high Kremen2 expression in CC was linked to poor overall survival and progression-free survival. Clinical correlation analysis highlighted that a high level of Kremen2 expression was strongly linked with tumour progression, particularly lymph node metastasis. Cox regression analysis highlighted that Kremen2 was an independent prognostic indicator for CC. Bioinformatic studies highlighted that Kremen2 might be associated with the immune status in CC. Conclusion: Increased Kremen2 could serve as a potential prognostic CC biomarker.
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Affiliation(s)
- Junxian Long
- Division of Colorectal and Anal Surgery, Department of Gastrointestinal Surgery, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, China
- Department of Breast and Thyroid Surgery, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Fengyun Cong
- Division of Colorectal and Anal Surgery, Department of Gastrointestinal Surgery, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, China
- Department of Gastroenteroanal Surgery, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Yousheng Wei
- Department of Gynecologic Oncology, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, China
| | - Jungang Liu
- Division of Colorectal and Anal Surgery, Department of Gastrointestinal Surgery, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, China
- Guangxi Clinical Research Center for Colorectal Cancer, Nanning, Guangxi, China
| | - Weizhong Tang
- Division of Colorectal and Anal Surgery, Department of Gastrointestinal Surgery, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, China
- Guangxi Clinical Research Center for Colorectal Cancer, Nanning, Guangxi, China
- *Correspondence: Weizhong Tang,
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Vlashi R, Zhang X, Wu M, Chen G. Wnt signaling: essential roles in osteoblast differentiation, bone metabolism and therapeutic implications for bone and skeletal disorders. Genes Dis 2022. [DOI: 10.1016/j.gendis.2022.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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8
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Jing Z, Liang Z, Yang L, Du W, Yu T, Tang H, Li C, Wei W. Bone formation and bone repair: The roles and crosstalk of osteoinductive signaling pathways. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.04.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Modern genetic and immunological aspects of the pathogenesis of impaired consolidation of fractures (literature review). ACTA BIOMEDICA SCIENTIFICA 2022. [DOI: 10.29413/abs.2022-7.2.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aim of this article is to analyze the genetic and immunological mechanisms of the development of fracture consolidation disorders at the present scientific stage.Materials and methods. The search for literary sources was carried out in the open electronic databases of scientific literature PubMed and eLIBRARY. Search depth – 10 years.Results. The review analyzes the literature data on the current state of the study of the molecular genetic mechanisms of reparative regeneration including the development of fracture consolidation disorders. The mechanisms of the most important links of pathogenesis which most often lead to various violations of the processes of bone tissue repair are considered.Conclusion. The process of bone tissue repair is multifaceted, and many factors are involved in its implementation, however, we would like to note that the leading role in the course of reparative regeneration is played by a personalized genetically programmed response to this pathological condition. Nevertheless, despite the undeniable progress of modern medicine in studying the processes of bone recovery after a fracture, there are still many “white” spots in this issue, which dictates the need for further comprehensive study in order to effectively treat patients with impaired consolidation.
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Brylka L, Jähn-Rickert K, Baranowsky A, Neven M, Horn M, Yorgan T, Wikman H, Werner S, Lübke A, Amling M, Busse B, Pantel K, Schinke T. Spine Metastases in Immunocompromised Mice after Intracardiac Injection of MDA-MB-231-SCP2 Breast Cancer Cells. Cancers (Basel) 2022; 14:cancers14030556. [PMID: 35158823 PMCID: PMC8833437 DOI: 10.3390/cancers14030556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/04/2022] Open
Abstract
Simple Summary Breast cancer cells typically metastasize to bone, where their interaction with bone remodeling cell types enhances metastatic outgrowth and osteolytic bone destruction. The respective knowledge is largely based on xenograft models, where human breast cancer cells are injected into immunocompromised mice. Importantly, however, whereas skeletal analyses in these animals are usually restricted to hindlimb bones, human skeletal metastases are far more frequent in the spine. Therefore, our study addressed the question, if breast cancer cells injected into immunocompromised mice would also metastasize to the spine, and if this process is influenced by the amount of trabecular bone. We injected an established breast cancer cell line into immunocompromised mice with or without a transgene causing severe osteoporosis. Importantly, we found more tumor cell clusters of different size in spine sections than in femora, but the presence of the transgene did not affect their spreading and metastatic outgrowth. Abstract Breast cancer cells frequently metastasize to bone, where their interaction with bone remodeling cell types enhances osteolytic bone destruction. Importantly, however, whereas skeletal analyses of xenograft models are usually restricted to hindlimb bones, human skeletal metastases are far more frequent in the spine, where trabecular bone mass is higher compared to femur or tibia. Here, we addressed whether breast cancer cells injected into immunocompromised mice metastasize to the spine and if this process is influenced by the amount of trabecular bone. We also took advantage of mice carrying the Col1a1-Krm2 transgene, which display severe osteoporosis. After crossing this transgene into the immunocompromised NSG background we injected MDA-MB-231-SCP2 breast cancer cells and analyzed their distribution three weeks thereafter. We identified more tumor cells and clusters of different size in spine sections than in femora, which allowed influences on bone remodeling cell types to be analyzed by comparing tumor-free to tumor-burdened areas. Unexpectedly, the Col1a1-Krm2 transgene did not affect spreading and metastatic outgrowth of MDA-MB-231-SCP2 cells, suggesting that bone tumor interactions are more relevant at later stages of metastatic progression.
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Affiliation(s)
- Laura Brylka
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Katharina Jähn-Rickert
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Anke Baranowsky
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Mona Neven
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Michael Horn
- Mildred Scheel Cancer Career Center, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Timur Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Harriet Wikman
- Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (H.W.); (S.W.)
| | - Stefan Werner
- Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (H.W.); (S.W.)
| | - Andreas Lübke
- Institute of Pathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
| | - Klaus Pantel
- Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (H.W.); (S.W.)
- Correspondence: (K.P.); (T.S.); Tel.: +49-40-7410-58057 (T.S.)
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (L.B.); (K.J.-R.); (A.B.); (M.N.); (T.Y.); (M.A.); (B.B.)
- Correspondence: (K.P.); (T.S.); Tel.: +49-40-7410-58057 (T.S.)
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Martínez-Gil N, Ugartondo N, Grinberg D, Balcells S. Wnt Pathway Extracellular Components and Their Essential Roles in Bone Homeostasis. Genes (Basel) 2022; 13:genes13010138. [PMID: 35052478 PMCID: PMC8775112 DOI: 10.3390/genes13010138] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/11/2022] Open
Abstract
The Wnt pathway is involved in several processes essential for bone development and homeostasis. For proper functioning, the Wnt pathway is tightly regulated by numerous extracellular elements that act by both activating and inhibiting the pathway at different moments. This review aims to describe, summarize and update the findings regarding the extracellular modulators of the Wnt pathway, including co-receptors, ligands and inhibitors, in relation to bone homeostasis, with an emphasis on the animal models generated, the diseases associated with each gene and the bone processes in which each member is involved. The precise knowledge of all these elements will help us to identify possible targets that can be used as a therapeutic target for the treatment of bone diseases such as osteoporosis.
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12
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Vollersen N, Zhao W, Rolvien T, Lange F, Schmidt FN, Sonntag S, Shmerling D, von Kroge S, Stockhausen KE, Sharaf A, Schweizer M, Karsak M, Busse B, Bockamp E, Semler O, Amling M, Oheim R, Schinke T, Yorgan TA. The WNT1 G177C mutation specifically affects skeletal integrity in a mouse model of osteogenesis imperfecta type XV. Bone Res 2021; 9:48. [PMID: 34759273 PMCID: PMC8580994 DOI: 10.1038/s41413-021-00170-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 05/28/2021] [Accepted: 06/27/2021] [Indexed: 12/27/2022] Open
Abstract
The recent identification of homozygous WNT1 mutations in individuals with osteogenesis imperfecta type XV (OI-XV) has suggested that WNT1 is a key ligand promoting the differentiation and function of bone-forming osteoblasts. Although such an influence was supported by subsequent studies, a mouse model of OI-XV remained to be established. Therefore, we introduced a previously identified disease-causing mutation (G177C) into the murine Wnt1 gene. Homozygous Wnt1G177C/G177C mice were viable and did not display defects in brain development, but the majority of 24-week-old Wnt1G177C/G177C mice had skeletal fractures. This increased bone fragility was not fully explained by reduced bone mass but also by impaired bone matrix quality. Importantly, the homozygous presence of the G177C mutation did not interfere with the osteoanabolic influence of either parathyroid hormone injection or activating mutation of LRP5, the latter mimicking the effect of sclerostin neutralization. Finally, transcriptomic analyses revealed that short-term administration of WNT1 to osteogenic cells induced not only the expression of canonical WNT signaling targets but also the expression of genes encoding extracellular matrix modifiers. Taken together, our data demonstrate that regulating bone matrix quality is a primary function of WNT1. They further suggest that individuals with WNT1 mutations should profit from existing osteoanabolic therapies.
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Affiliation(s)
- Nele Vollersen
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Wenbo Zhao
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Tim Rolvien
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Fabiola Lange
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Felix Nikolai Schmidt
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Stephan Sonntag
- PolyGene AG, 8153, Rümlang, Switzerland.,ETH Phenomics Center (EPIC), ETH Zürich, 8092, Zürich, Switzerland
| | | | - Simon von Kroge
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Kilian Elia Stockhausen
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Ahmed Sharaf
- Neuronal and Cellular Signal Transduction, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center, Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Meliha Karsak
- Neuronal and Cellular Signal Transduction, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Ernesto Bockamp
- Institute for Translational Immunology and Research Center for Immunotherapy, University Medical Center, Johannes Gutenberg University, D 55131, Mainz, Germany
| | - Oliver Semler
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50937, Cologne, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany.
| | - Timur Alexander Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany.
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13
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Chen B, Wang SQ, Huang J, Xu W, Lv H, Nie C, Wang J, Zhao H, Liu Y, Li J, Lu C, Zhang J, Chen XB. Knockdown of Kremen2 Inhibits Tumor Growth and Migration in Gastric Cancer. Front Oncol 2021; 10:534095. [PMID: 33489867 PMCID: PMC7817645 DOI: 10.3389/fonc.2020.534095] [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: 03/10/2020] [Accepted: 11/11/2020] [Indexed: 12/19/2022] Open
Abstract
Kremen2 (Krm2) plays an important role in embryonic development, bone formation, and tumorigenesis as a crucial regulator of classical Wnt/β-catenin signaling pathway. However, the role of Krm2 in gastric cancer is not clear. The aim of this study was to explore the regulatory role of Krm2 in the tumorigenesis and metastasis of gastric cancer. It was demonstrated that, compared to para-cancerous tissues, Krm2 was significantly up-regulated in gastric cancer tissues and was positively correlated with the pathological grade of gastric cancer patients. Given that Krm2 is abundantly expressed in most tested gastric cancer cell lines, Krm2 knockdown cell models were established and further used to construct mice xenograft model. After knocking down Krm2, both the cell survival in vitro and tumorigenesis in vivo of gastric cancer cells were inhibited. At the same time, knockdown of Krm2 induced apoptosis, cell cycle arrest at G2/M phase and repression of migration in gastric cancer cells in vitro. Mechanistically, we found that knockdown of Krm2 suppressed PI3K/Akt pathway. Therefore, we revealed the novel role and the molecular mechanism of Krm2 in promoting the tumorigenesis and metastasis in gastric cancer. Krm2 can be a potent candidate for designing of targeted therapy.
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Affiliation(s)
- Beibei Chen
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China.,State Key Laboratory of Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, China
| | - Sai-Qi Wang
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China.,State Key Laboratory of Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, China
| | - Jinxi Huang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Weifeng Xu
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Huifang Lv
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Caiyun Nie
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Jianzheng Wang
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Huichen Zhao
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Yingjun Liu
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China
| | - Jitian Li
- Department of Biological Sciences, University of Texas, El Paso, TX, United States
| | - Canrong Lu
- Department of General surgery, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Jianying Zhang
- Department of Biological Sciences, University of Texas, El Paso, TX, United States
| | - Xiao-Bing Chen
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China.,State Key Laboratory of Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, China
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14
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Yorgan TA, Rolvien T, Stürznickel J, Vollersen N, Lange F, Zhao W, Baranowsky A, Rosenthal L, Hermans-Borgmeyer I, Sharaf A, Karsak M, David JP, Oheim R, Amling M, Schinke T. Mice Carrying a Ubiquitous R235W Mutation of Wnt1 Display a Bone-Specific Phenotype. J Bone Miner Res 2020; 35:1726-1737. [PMID: 32369212 DOI: 10.1002/jbmr.4043] [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: 11/29/2019] [Revised: 04/17/2020] [Accepted: 04/27/2020] [Indexed: 12/14/2022]
Abstract
Since a key function of Wnt1 in brain development was established early on through the generation of non-viable Wnt1-deficient mice, it was initially surprising that WNT1 mutations were found to cause either early-onset osteoporosis (EOOP) or osteogenesis imperfecta type XV (OI-XV). The deduced function of Wnt1 as an osteoanabolic factor has been confirmed in various mouse models with bone-specific inactivation or overexpression, but mice carrying disease-causing Wnt1 mutations have not yet been described. Triggered by the clinical analysis of EOOP patients carrying a heterozygous WNT1 mutation (p.R235W), we introduced this mutation into the murine Wnt1 gene to address the question of whether this would cause a skeletal phenotype. We observed that Wnt1+/R235W and Wnt1R235W/R235W mice were born at the expected Mendelian ratio and that they did not display postnatal lethality or obvious nonskeletal phenotypes. At 12 weeks of age, the homozygous presence of the Wnt1 mutation was associated with reduced trabecular and cortical bone mass, explained by a lower bone formation rate compared with wild-type littermates. At 52 weeks of age, we also observed a moderate bone mass reduction in heterozygous Wnt1+/R235W mice, thereby underscoring their value as a model of WNT1-dependent EOOP. Importantly, when we treated wild-type and Wnt1+/R235W mice by daily injection of parathyroid hormone (PTH), we detected the same osteoanabolic influence in both groups, together with an increased cortical thickness in the mutant mice. Our data demonstrate the pathogenicity of the WNT1-R235W mutation, confirm that controlling skeletal integrity is the primary physiological function of Wnt1, and suggest that osteoanabolic treatment with teriparatide should be applicable for individuals with WNT1-dependent EOOP. © 2020 American Society for Bone and Mineral Research.
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Affiliation(s)
- Timur Alexander Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tim Rolvien
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Orthopedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Julian Stürznickel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nele Vollersen
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fabiola Lange
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Wenbo Zhao
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anke Baranowsky
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lana Rosenthal
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Irm Hermans-Borgmeyer
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ahmed Sharaf
- Neuronal and Cellular Signal Transduction, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Meliha Karsak
- Neuronal and Cellular Signal Transduction, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jean-Pierre David
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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15
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Schupbach D, Comeau-Gauthier M, Harvey E, Merle G. Wnt modulation in bone healing. Bone 2020; 138:115491. [PMID: 32569871 DOI: 10.1016/j.bone.2020.115491] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 12/31/2022]
Abstract
Genetic studies have been instrumental in the field of orthopaedics for finding tools to improve the standard management of fractures and delayed unions. The Wnt signaling pathway that is crucial for development and maintenance of many organs also has a very promising pathway for enhancement of bone regeneration. The Wnt pathway has been shown to have a direct effect on stem cells during bone regeneration, making Wnt a potential target to stimulate bone repair after trauma. A more complete view of how Wnt influences animal bone regeneration has slowly come to light. This review article provides an overview of studies done investigating the modulation of the canonical Wnt pathway in animal bone regeneration models. This not only includes a summary of the recent work done elucidating the roles of Wnt and β-catenin in fracture healing, but also the results of thirty transgenic studies, and thirty-eight pharmacological studies. Finally, we discuss the discontinuation of sclerostin clinical trials, ongoing clinical trials with lithium, the results of Dkk antibody clinical trials, the shift into combination therapies and the future opportunities to enhance bone repair and regeneration through the modulation of the Wnt signaling pathway.
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Affiliation(s)
- Drew Schupbach
- Department of Surgery, Division of Orthopedic Surgery, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Room A10-110, Montreal, Québec H3G 1A4, Canada; Experimental Surgery, Faculty of Medicine, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Room A7-117, Montreal, Québec H3G 1A4, Canada.
| | - Marianne Comeau-Gauthier
- Department of Surgery, Division of Orthopedic Surgery, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Room A10-110, Montreal, Québec H3G 1A4, Canada; Experimental Surgery, Faculty of Medicine, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Room A7-117, Montreal, Québec H3G 1A4, Canada.
| | - Edward Harvey
- Department of Surgery, Division of Orthopedic Surgery, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Room A10-110, Montreal, Québec H3G 1A4, Canada.
| | - Geraldine Merle
- Department of Surgery, Division of Orthopedic Surgery, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Room A10-110, Montreal, Québec H3G 1A4, Canada; Department of Chemical Engineering, Polytechnique Montreal, 2500, chemin de Polytechnique, Montréal, Québec H3T 1J4, Canada.
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16
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Meszaros K, Patocs A. Glucocorticoids Influencing Wnt/β-Catenin Pathway; Multiple Sites, Heterogeneous Effects. Molecules 2020; 25:molecules25071489. [PMID: 32218328 PMCID: PMC7181001 DOI: 10.3390/molecules25071489] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/17/2020] [Accepted: 03/23/2020] [Indexed: 02/06/2023] Open
Abstract
Glucocorticoid hormones are vital; their accurate operation is a necessity at all ages and in all life situations. Glucocorticoids regulate diverse physiological processes and they use many signaling pathways to fulfill their effect. As the operation of these hormones affects many organs, the excess of glucocorticoids is actually detrimental to the whole human body. The endogenous glucocorticoid excess is a relatively rare condition, but a significant proportion of adult people uses glucocorticoid medication for the treatment of chronic illnesses, therefore they are exposed to the side effects of long-term glucocorticoid treatment. Our review summarizes the adverse effects of glucocorticoid excess affecting bones, adipose tissue, brain and skin, focusing on those effects which involve the Wnt/β-catenin pathway.
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Affiliation(s)
| | - Attila Patocs
- Hereditary Tumours Research Group, 1089 Budapest, Hungary;
- Department of Laboratory Medicine, Semmelweis University, 1089 Budapest, Hungary
- Department of Molecular Genetics, National Institute of Oncology, 1122 Budapest, Hungary
- Correspondence: ; Tel.: +36-1-266-0926; Fax: +36-1-266-0816
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17
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Lack of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Disturbs Callus Formation. J Mol Neurosci 2019; 71:1543-1555. [PMID: 31808034 PMCID: PMC8349325 DOI: 10.1007/s12031-019-01448-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 11/13/2019] [Indexed: 12/20/2022]
Abstract
Pituitary adenylate cyclase–activating polypeptide (PACAP) is a naturally secreted signaling peptide and has important regulatory roles in the differentiation of the central nervous system and its absence results in disorders in femur development. PACAP has an important function in prevention of oxidative stress or mechanical stress in chondrogenesis but little is known about its function in bone regeneration. A new callus formation model was set to investigate its role in bone remodeling. Fracturing was 5 mm distal from the proximal articular surface of the tibia and the depth was 0.5 mm. Reproducibility of callus formation was investigated with CT 3, 7, and 21 days after the operation. Absence of PACAP did not alter the alkaline phosphatase (ALP) activation in PACAP KO healing process. In developing callus, the expression of collagen type I increased in wild-type (WT) and PACAP KO mice decreased to the end of healing process. Expression of the elements of BMP signaling was disturbed in the callus formation of PACAP KO mice, as bone morphogenic protein 4 (BMP4) and 6 showed an early reduction in bone regeneration. However, elevated Smad1 expression was demonstrated in PACAP KO mice. Our results indicate that PACAP KO mice show various signs of disturbed bone healing and suggest PACAP compensatory and fine tuning effects in proper bone regeneration.
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18
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Houschyar KS, Tapking C, Borrelli MR, Popp D, Duscher D, Maan ZN, Chelliah MP, Li J, Harati K, Wallner C, Rein S, Pförringer D, Reumuth G, Grieb G, Mouraret S, Dadras M, Wagner JM, Cha JY, Siemers F, Lehnhardt M, Behr B. Wnt Pathway in Bone Repair and Regeneration - What Do We Know So Far. Front Cell Dev Biol 2019; 6:170. [PMID: 30666305 PMCID: PMC6330281 DOI: 10.3389/fcell.2018.00170] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/30/2018] [Indexed: 02/05/2023] Open
Abstract
Wnt signaling plays a central regulatory role across a remarkably diverse range of functions during embryonic development, including those involved in the formation of bone and cartilage. Wnt signaling continues to play a critical role in adult osteogenic differentiation of mesenchymal stem cells. Disruptions in this highly-conserved and complex system leads to various pathological conditions, including impaired bone healing, autoimmune diseases and malignant degeneration. For reconstructive surgeons, critically sized skeletal defects represent a major challenge. These are frequently associated with significant morbidity in both the recipient and donor sites. The Wnt pathway is an attractive therapeutic target with the potential to directly modulate stem cells responsible for skeletal tissue regeneration and promote bone growth, suggesting that Wnt factors could be used to promote bone healing after trauma. This review summarizes our current understanding of the essential role of the Wnt pathway in bone regeneration and repair.
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Affiliation(s)
- Khosrow S Houschyar
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Christian Tapking
- Department of Surgery, Shriners Hospital for Children-Galveston, University of Texas Medical Branch, Galveston, TX, United States.,Department of Hand, Plastic and Reconstructive Surgery, Burn Trauma Center, BG Trauma Center Ludwigshafen, University of Heidelberg, Heidelberg, Germany
| | - Mimi R Borrelli
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Daniel Popp
- Department of Surgery, Shriners Hospital for Children-Galveston, University of Texas Medical Branch, Galveston, TX, United States.,Division of Hand, Plastic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
| | - Dominik Duscher
- Department of Plastic Surgery and Hand Surgery, Technical University Munich, Munich, Germany
| | - Zeshaan N Maan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Malcolm P Chelliah
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Jingtao Li
- State Key Laboratory of Oral Diseases and Department of Oral Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Kamran Harati
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Christoph Wallner
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Susanne Rein
- Department of Plastic and Hand Surgery-Burn Center-Clinic St. Georg, Leipzig, Germany
| | - Dominik Pförringer
- Clinic and Policlinic of Trauma Surgery, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany
| | - Georg Reumuth
- Department of Plastic and Hand Surgery, Burn Unit, Trauma Center Bergmannstrost Halle, Halle, Germany
| | - Gerrit Grieb
- Department of Plastic Surgery and Hand Surgery, Gemeinschaftskrankenhaus Havelhoehe, Teaching Hospital of the Charité Berlin, Berlin, Germany
| | - Sylvain Mouraret
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, United States.,Department of Periodontology, Service of Odontology, Rothschild Hospital, AP-HP, Paris 7 - Denis, Diderot University, U.F.R. of Odontology, Paris, France
| | - Mehran Dadras
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Johannes M Wagner
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Jungul Y Cha
- Orthodontic Department, College of Dentistry, Yonsei University, Seoul, South Korea
| | - Frank Siemers
- Department of Plastic and Hand Surgery, Burn Unit, Trauma Center Bergmannstrost Halle, Halle, Germany
| | - Marcus Lehnhardt
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Björn Behr
- Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
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19
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20
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Mazon M, Julien J, Ung RV, Picard S, Hamoudi D, Tam R, Filiatrault J, Frenette J, Mac-Way F, Carreau M. Deletion of the Fanconi Anemia C Gene in Mice Leads to Skeletal Anomalies and Defective Bone Mineralization and Microarchitecture. J Bone Miner Res 2018; 33:2007-2020. [PMID: 29989666 DOI: 10.1002/jbmr.3546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/07/2018] [Accepted: 07/04/2018] [Indexed: 12/12/2022]
Abstract
Fanconi anemia (FA) is a rare genetic disorder associated with a progressive decline in hematopoietic stem cells leading to bone marrow failure. FA is also characterized by a variety of developmental defects including short stature and skeletal malformations. More than half of children affected with FA have radial-ray abnormalities, and many patients have early onset osteopenia/osteoporosis. Although many Fanconi anemia genes have been identified and a molecular pathway defined, the underlying mechanism leading to bone defects remains elusive. To understand the role of FA genes in skeletal development and bone microarchitecture, we evaluated bone physiology during embryogenesis and in adult FancA- and FancC-deficient mice. We found that both FancA-/- and FancC-/- embryos have abnormal skeletal development shown by skeletal malformations, growth delay, and reduced bone mineralization. FancC-/- adult mice present altered bone morphology and microarchitecture with a significant decrease in cortical bone mineral density in a sex-specific manner. Mechanical testing revealed that male but not female FancC-/- mice show reduced bone strength compared with their wild-type littermates. Ex vivo cultures showed that FancA-/- and FancC-/- bone marrow-derived mesenchymal stem cells (BM MSC) have impaired differentiation capabilities together with altered gene expression profiles. Our results suggest that defective bone physiology in FA occurs in utero and possibly results from altered BM MSC function. These results provide valuable insights into the mechanism involved in FA skeletal defects. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
| | | | | | | | | | - Rose Tam
- CHU de Québec Research Center, Québec, Canada
| | | | - Jérôme Frenette
- CHU de Québec Research Center, Québec, Canada.,Department of Readaptation, Faculty of Medicine, Université Laval, Québec, Canada
| | - Fabrice Mac-Way
- CHU de Québec Research Center, Québec, Canada.,Division of Nephrology, Faculty and Department of Medicine, Université Laval, Québec, Canada
| | - Madeleine Carreau
- CHU de Québec Research Center, Québec, Canada.,Department of Pediatrics, Faculty of Medicine, Université Laval, Québec, Canada
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21
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Clines KL, Clines GA. DKK1 and Kremen Expression Predicts the Osteoblastic Response to Bone Metastasis. Transl Oncol 2018; 11:873-882. [PMID: 29772510 PMCID: PMC6051964 DOI: 10.1016/j.tranon.2018.04.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/19/2018] [Accepted: 04/24/2018] [Indexed: 12/17/2022] Open
Abstract
Bone metastasis is a complication of advanced breast and prostate cancer. Tumor-secreted Dickkopf homolog 1 (DKK1), an inhibitor of canonical Wnt signaling and osteoblast differentiation, was proposed to regulate the osteoblastic response to metastatic cancer in bone. The objectives of this study were to compare DKK1 expression with the in vivo osteoblastic response in a panel of breast and prostate cancer cell lines, and to discover mechanisms that regulate cancer DKK1 expression. DKK1 expression was highest in MDA-MB-231 and PC3 cells that produce osteolytic lesions, and hence a suppressed osteoblastic response, in animal models of bone metastasis. LnCaP, C4-2B, LuCaP23.1, T47D, ZR-75-1, MCF-7, ARCaP and ARCaPM cancer cells that generate osteoblastic, mixed or no bone lesions had the lowest DKK1 expression. The cell lines with negligible expression, LnCaP, C4-2B and T47D, exhibited methylation of the DKK1 promoter. Canonical Wnt signaling activity was then determined and found in all cell lines tested, even in the MDA-MB-231 and PC3 cell lines despite sizeable amounts of DKK1 protein expression expected to block canonical Wnt signaling. A mechanism of DKK1 resistance in the osteolytic cell lines was investigated and determined to be at least partially due to down-regulation of the DKK1 receptors Kremen1 and Kremen2 in the MDA-MB-231 and PC3 cell lines. Combined DKK1 and Kremen expression in cancer cells may serve as predictive markers of the osteoblastic response of breast and prostate cancer bone metastasis.
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Affiliation(s)
- Katrina L Clines
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI
| | - Gregory A Clines
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI; Veterans Affairs Medical Center, Ann Arbor, MI.
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Zhu S, He H, Zhang C, Wang H, Gao C, Yu X, He C. Effects of pulsed electromagnetic fields on postmenopausal osteoporosis. Bioelectromagnetics 2017; 38:406-424. [PMID: 28665487 DOI: 10.1002/bem.22065] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 06/05/2017] [Indexed: 02/05/2023]
Abstract
Postmenopausal osteoporosis (PMOP) is considered to be a well-defined subject that has caused high morbidity and mortality. In elderly women diagnosed with PMOP, low bone mass and fragile bone strength have been proven to significantly increase risk of fragility fractures. Currently, various anabolic and anti-resorptive therapies have been employed in an attempt to retain healthy bone mass and strength. Pulsed electromagnetic fields (PEMFs), first applied in treating patients with delayed fracture healing and nonunions, may turn out to be another potential and effective therapy for PMOP. PEMFs can enhance osteoblastogenesis and inhibit osteoclastogenesis, thus contributing to an increase in bone mass and strength. However, accurate mechanisms of the positive effects of PEMFs on PMOP remain to be further elucidated. This review attempts to summarize recent advances of PEMFs in treating PMOP based on clinical trials, and animal and cellular studies. Possible mechanisms are also introduced, and the future possibility of application of PEMFs on PMOP are further explored and discussed. Bioelectromagnetics. 38:406-424, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Siyi Zhu
- Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P. R. China
- Rehabilitation Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, P. R. China
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Hongchen He
- Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Chi Zhang
- Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P. R. China
- Rehabilitation Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Haiming Wang
- Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P. R. China
- Rehabilitation Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Chengfei Gao
- Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P. R. China
- Rehabilitation Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Chengqi He
- Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P. R. China
- Rehabilitation Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, P. R. China
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Gao F, Xu F, Wu D, Cheng J, Xia P. Identification of novel genes associated with fracture healing in osteoporosis induced by Krm2 overexpression or Lrp5 deficiency. Mol Med Rep 2017; 15:3969-3976. [PMID: 28487939 PMCID: PMC5436207 DOI: 10.3892/mmr.2017.6544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 01/30/2017] [Indexed: 11/27/2022] Open
Abstract
The aim of the present study was to screen potential key genes associated with osteoporotic fracture healing. The microarray data from the Gene Expression Omnibus database accession number GSE51686, were downloaded and used to identify differentially expressed genes (DEGs) in fracture callus tissue samples obtained from the femora of type I collagen (Col1a1)-kringle containing transmembrane protein 2 (Krm2) mice and low density lipoprotein receptor-related protein 5−/− (Lrp5−/−) transgenic mice of osteoporosis compared with those in wild-type (WT) mice. Enrichment analysis was performed to reveal the DEG function. In addition, protein-protein interactions (PPIs) of DEGs were analyzed using the Search Tool for the Retrieval of Interacting Genes database. The coexpression associations between hub genes in the PPI network were investigated, and a coexpression network was constructed. A total of 841 DEGs (335 upregulated and 506 downregulated) were identified in the Col1a1-Krm2 vs. the WT group, and 50 DEGs (16 upregulated and 34 downregulated) were identified in the Lrp5−/− vs. the WT group. The DEGs in Col1a1-Krm2 mice were primarily associated with immunity and cell adhesion (GO: 0007155) functions. By contrast, the DEGs in Lrp5−/− mice were significantly associated with muscle system process (GO: 0003012) and regulation of transcription (GO: 0006355). In addition, a series of DEGs demonstrated a higher score in the PPI network, and were observed to be coexpressed in the coexpression network, and included thrombospondin 2 (Thbs2), syndecan 2 (Sdc2), FK506 binding protein 10 (Fkbp10), 2–5-oligoadneylate synthase-like protein 2 (Oasl2), interferon induced protein with tetratricopeptide repeats (Ifit) 1 and Ifit2. Thbs2 and Sdc2 were significantly correlated with extracellular matrix-receptor interactions. The results suggest that Thbs2, Sdc2, Fkbp10, Oasl2, Ifit1 and Ifit2 may serve important roles during the fracture healing process in osteoporosis. In addition, this is the first study to demonstrate that Sdc2, Fkbp10, Oasl2, Ifit1 and Ifit2 may be associated with osteoporotic fracture healing.
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Affiliation(s)
- Feng Gao
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Feng Xu
- Department of Spine Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Dankai Wu
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Jieping Cheng
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Peng Xia
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
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Zebisch M, Jackson VA, Zhao Y, Jones EY. Structure of the Dual-Mode Wnt Regulator Kremen1 and Insight into Ternary Complex Formation with LRP6 and Dickkopf. Structure 2016; 24:1599-605. [PMID: 27524201 PMCID: PMC5014086 DOI: 10.1016/j.str.2016.06.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/12/2016] [Accepted: 06/13/2016] [Indexed: 01/17/2023]
Abstract
Kremen 1 and 2 have been identified as co-receptors for Dickkopf (Dkk) proteins, hallmark secreted antagonists of canonical Wnt signaling. We present here three crystal structures of the ectodomain of human Kremen1 (KRM1ECD) at resolutions between 1.9 and 3.2 Å. KRM1ECD emerges as a rigid molecule with tight interactions stabilizing a triangular arrangement of its Kringle, WSC, and CUB structural domains. The structures reveal an unpredicted homology of the WSC domain to hepatocyte growth factor. We further report the general architecture of the ternary complex formed by the Wnt co-receptor Lrp5/6, Dkk, and Krm, determined from a low-resolution complex crystal structure between β-propeller/EGF repeats (PE) 3 and 4 of the Wnt co-receptor LRP6 (LRP6PE3PE4), the cysteine-rich domain 2 (CRD2) of DKK1, and KRM1ECD. DKK1CRD2 is sandwiched between LRP6PE3 and KRM1Kringle-WSC. Modeling studies supported by surface plasmon resonance suggest a direct interaction site between Krm1CUB and Lrp6PE2.
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Affiliation(s)
- Matthias Zebisch
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
| | - Verity A Jackson
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Yuguang Zhao
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
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Quent VM, Theodoropoulos C, Hutmacher DW, Reichert JC. Differential osteogenicity of multiple donor-derived human mesenchymal stem cells and osteoblasts in monolayer, scaffold-based 3D culture and in vivo. ACTA ACUST UNITED AC 2016; 61:253-66. [DOI: 10.1515/bmt-2014-0159] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 02/13/2015] [Indexed: 11/15/2022]
Abstract
Abstract
We set out to compare the osteogenicity of human mesenchymal stem (hMSCs) and osteoblasts (hOBs). Upon osteogenic induction in monolayer, hMSCs showed superior matrix mineralization expressing characteristic bone-related genes. For scaffold cultures, both cell types presented spindle-shaped, osteoblast-like morphologies forming a dense, interconnected network of high viability. On the scaffolds, hOBs proliferated faster. A general upregulation of parathyroid hormone-related protein (PTHrP), osteoprotegrin (OPG), receptor activator of NF-κB ligand (RANKL), sclerostin (SOST), and dentin matrix protein 1 (DMP1) was observed for both cell types. Simultaneously, PTHrP, RANKL and DMP-1 expression decreased under osteogenic stimulation, while OPG and SOST increased significantly. Following transplantation into NOD/SCID mice, μCT and histology showed increased bone deposition with hOBs. The bone was vascularized, and amounts further increased for both cell types after recombinant human bone morphogenic protein 7 (rhBMP-7) addition also stimulating osteoclastogenesis. Complete bone organogenesis was evidenced by the presence of osteocytes and hematopoietic precursors. Our study results support the asking to develop 3D cellular models closely mimicking the functions of living tissues suitable for in vivo translation.
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Wang C, Yu T, Tan L, Cheng J. Bioinformatics analysis of gene expression profile in callus tissues of osteoporotic phenotype mice induced by osteoblast-specific Krm2 overexpression. Int J Rheum Dis 2016; 19:1263-1271. [PMID: 26929007 DOI: 10.1111/1756-185x.12840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE The aim of this study was to explore the molecular mechanism of fracture healing in osteoporotic mice. METHODS The gene expression profiles of callus tissues of osteoporotic mice and controls were obtained from Gene Expression Omnibus database. The differentially expressed genes (DEGs) and their related biological function and pathways were investigated. In addition, the protein-protein interaction (PPI) network was constructed for DEG encoding proteins and the differentially expressed transcriptional factor was screened. RESULTS There were 275 up-regulated genes and 347 down-regulated genes. The collagen metabolic process biological function was significantly enriched by down-regulated genes. Extracellular matrix (ECM)-receptor interaction was a significant pathway that was enriched by differentially expressed genes. In PPI (protein-protein interaction) network, Pcna was the significant node with highest connective degrees. Other hub nodes, such as Ccnb2 and Rrm2, were closely associated with the p53 signaling pathway. Tal1 and Smad6 were found to be differentially expressed transcription factors. CONCLUSION The dysregulated collagen metabolic process, ECM-receptor interaction and p53 signaling pathway may be responsible for impaired fracture healing of osteoporotic mice. The hub nodes (such as Ccnb2 and Rrm2) and differentially expressed TFs (such as Tal1 and Smad6) play a critical role in bone remodeling of osteoporotic individuals.
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Affiliation(s)
- Chengxue Wang
- Department of Trauma, The First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Tiecheng Yu
- Department of Trauma, The First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Lei Tan
- Department of Trauma, The First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Jieping Cheng
- Department of Orthopaedics, The Second Hospital of Jilin University, Changchun, Jilin Province, China
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Abstract
Osteoporosis is a chronic systemic bone disease of growing relevance due to the on-going demographic change. Since the underlying regulatory mechanisms of this critical illness are still not fully understood and treatment options are not satisfactorily resolved, there is still a great need for osteoporosis research in general and animal models in particular. Ovariectomized rodents are standard animal models for postmenopausal osteoporosis and highly attractive due to the possibility to specifically modify their genetic background. However, some aspects can only be addressed in large animal models; such as metaphyseal fracture healing and advancement of orthopedic implants. Among other large animal models sheep in particular have been proven invaluable for osteoporosis research in this context. In conclusion, today we are able to influence the bone metabolism in animals causing a more or less pronounced systemic bone loss and structural deterioration comparable to the situation found in patients suffering from osteoporosis. However, there is no perfect model for osteoporosis, but a variety of models appropriate for answering specific questions. Though, the appropriateness of an animal model is not only defined in regard to the similarity to human physiology and the disease itself, but also in regard to acquisition, housing requirements, handling, costs, and particularly ethical concerns and animal welfare.
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Affiliation(s)
- Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Pia Pogoda
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
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Yorgan TA, Peters S, Jeschke A, Benisch P, Jakob F, Amling M, Schinke T. The Anti-Osteoanabolic Function of Sclerostin Is Blunted in Mice Carrying a High Bone Mass Mutation of Lrp5. J Bone Miner Res 2015; 30:1175-83. [PMID: 25640331 DOI: 10.1002/jbmr.2461] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/23/2014] [Accepted: 01/13/2015] [Indexed: 12/17/2022]
Abstract
Activating mutations of the putative Wnt co-receptor Lrp5 or inactivating mutations of the secreted molecule Sclerostin cause excessive bone formation in mice and humans. Previous studies have suggested that Sclerostin functions as an Lrp5 antagonist, yet clear in vivo evidence was still missing, and alternative mechanisms have been discussed. Moreover, because osteoblast-specific inactivation of β-catenin, the major intracellular mediator of canonical Wnt signaling, primarily affected bone resorption, it remained questionable, whether Sclerostin truly acts as a Wnt signaling antagonist by interacting with Lrp5. In an attempt to address this relevant question, we generated a mouse model (Col1a1-Sost) with transgenic overexpression of Sclerostin under the control of a 2.3-kb Col1a1 promoter fragment. These mice displayed the expected low bone mass phenotype as a consequence of reduced bone formation. The Col1a1-Sost mice were then crossed with two mouse lines carrying different high bone mass mutations of Lrp5 (Lrp5(A170V) and Lrp5(G213V)), both of them potentially interfering with Sclerostin binding. Using µCT-scanning and histomorphometry we found that the anti-osteoanabolic influence of Sclerostin overexpression was not observed in Lrp5(A213V/A213V) mice and strongly reduced in Lrp5(A170V/A170V) mice. As a control we applied the same strategy with mice overexpressing the transmembrane Wnt signaling antagonist Krm2 and found that the anti-osteoanabolic influence of the Col1a1-Krm2 transgene was not affected by either of the Lrp5 mutations. Taken together, our data support the concept that Sclerostin inhibits bone formation through Lrp5 interaction, yet their physiological relevance remains to be established.
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Affiliation(s)
- Timur A Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stephanie Peters
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anke Jeschke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peggy Benisch
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Franz Jakob
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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MacInnes SJ, Del Vescovo E, Kiss-Toth E, Ollier WER, Kay PR, Gordon A, Greenfield EM, Wilkinson MJ. Genetic variation in inflammatory and bone turnover pathways and risk of osteolytic responses to prosthetic materials. J Orthop Res 2015; 33:193-8. [PMID: 25399506 DOI: 10.1002/jor.22755] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/29/2014] [Indexed: 02/04/2023]
Abstract
Wear particle-induced inflammatory bone loss (osteolysis) is the leading cause of total hip arthroplasty (THA) failure. Individual susceptibility to osteolysis is modulated by genetic variation. In this 2-stage case-control association study we examined whether variation within candidate genes in inflammatory and bone turnover signaling pathways associates with susceptibility to osteolysis and time to prosthesis failure. We examined two cohorts, comprising 758 (347 male) Caucasian subjects who had undergone THA with a metal on polyethylene bearing couple; 315 of whom had developed osteolysis. Key genes within inflammatory, bone resorption, and bone formation pathways were screened for common variants by pairwise-SNP tagging using a 2-stage association analysis approach. In the discovery cohort four SNPs within RANK, and one each within KREMEN2, OPG, SFRP1, and TIRAP (p < 0.05) were associated with osteolysis susceptibility. Two SNPs within LRP6, and one each within LRP5, NOD2, SOST, SQSTM1, TIRAP, and TRAM associated with time to implant failure (p < 0.05). Meta-analysis of the two cohorts identified four SNPs within RANK, and one each within KREMEN2, OPG, SFRP1, and TIRAP associated with osteolysis susceptibility (p < 0.05). Genetic variation within inflammatory signaling and bone turnover pathways may play a role in susceptibility to osteolysis.
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Affiliation(s)
- Scott J MacInnes
- Department of Human Metabolism, University of Sheffield, Sheffield, United Kingdom
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Brommage R, Liu J, Hansen GM, Kirkpatrick LL, Potter DG, Sands AT, Zambrowicz B, Powell DR, Vogel P. High-throughput screening of mouse gene knockouts identifies established and novel skeletal phenotypes. Bone Res 2014; 2:14034. [PMID: 26273529 PMCID: PMC4472125 DOI: 10.1038/boneres.2014.34] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 12/13/2022] Open
Abstract
Screening gene function in vivo is a powerful approach to discover novel drug targets. We present high-throughput screening (HTS) data for 3 762 distinct global gene knockout (KO) mouse lines with viable adult homozygous mice generated using either gene-trap or homologous recombination technologies. Bone mass was determined from DEXA scans of male and female mice at 14 weeks of age and by microCT analyses of bones from male mice at 16 weeks of age. Wild-type (WT) cagemates/littermates were examined for each gene KO. Lethality was observed in an additional 850 KO lines. Since primary HTS are susceptible to false positive findings, additional cohorts of mice from KO lines with intriguing HTS bone data were examined. Aging, ovariectomy, histomorphometry and bone strength studies were performed and possible non-skeletal phenotypes were explored. Together, these screens identified multiple genes affecting bone mass: 23 previously reported genes (Calcr, Cebpb, Crtap, Dcstamp, Dkk1, Duoxa2, Enpp1, Fgf23, Kiss1/Kiss1r, Kl (Klotho), Lrp5, Mstn, Neo1, Npr2, Ostm1, Postn, Sfrp4, Slc30a5, Slc39a13, Sost, Sumf1, Src, Wnt10b), five novel genes extensively characterized (Cldn18, Fam20c, Lrrk1, Sgpl1, Wnt16), five novel genes with preliminary characterization (Agpat2, Rassf5, Slc10a7, Slc26a7, Slc30a10) and three novel undisclosed genes coding for potential osteoporosis drug targets.
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Affiliation(s)
| | - Jeff Liu
- Lexicon Pharmaceuticals , The Woodlands, TX, USA
| | | | | | | | | | | | | | - Peter Vogel
- Lexicon Pharmaceuticals , The Woodlands, TX, USA
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Simpson CA, Foer D, Lee GS, Bihuniak J, Sun B, Sullivan R, Belsky J, Insogna KL. Serum levels of sclerostin, Dickkopf-1, and secreted frizzled-related protein-4 are not changed in individuals with high bone mass causing mutations in LRP5. Osteoporos Int 2014; 25:2383-8. [PMID: 24927689 PMCID: PMC4659359 DOI: 10.1007/s00198-014-2767-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 06/04/2014] [Indexed: 12/17/2022]
Abstract
SUMMARY We compared circulating levels of Wnt inhibitors among patients with high bone mass mutations in LRP5, unaffected kindred, and unrelated normal controls. Inhibitors were unchanged in affected and unaffected kindred. We saw no meaningful differences between controls and affected individuals. LRP5 signaling may not influence circulating levels of these inhibitors. INTRODUCTION It is thought that gain-of-function mutations in LRP5 result in high bone mass syndromes because these allelic variants confer resistance to the actions of endogenous inhibitors of Wnt signaling. We therefore attempted to determine if circulating levels of Wnt inhibitors are altered in patients with gain-of-function mutations in LRP5. METHODS This is a cross-sectional study in a university research center. Serum was collected from consented volunteers known to have either the G171V or N198S gain-of-function mutations in LRP5, kindred members affected with either mutation, unrelated kindred, and unrelated normal age-matched controls. BMD was provided or measured on site. RESULTS There were no significant differences found in the serum levels of sclerostin (SOST), Dickkopf-1 (Dkk-1), or secreted frizzled-related protein-4 (SFRP-4) in affected vs. unaffected individuals from different kindreds or when compared to age-matched unrelated normal individuals. Mean serum SOST values in affected and unaffected kindred members and unrelated normal controls were 52.7 ± 6.1, 36.5 ± 9.6, and 54.8 ± 5.4, respectively. For Dkk-1, the values were 25.9 ± 3.4, 25.7 ± 3.0, and 17.3 ± 2.3 and for SFRP-4, 38.1 ± 2.3, 39.8 ± 3.6, and 28.5 ± 1.7. Serum levels of RANKL and osteoprotegerin (OPG) were not different in the three groups. CONCLUSIONS Circulating levels of endogenous Wnt inhibitors do not change in patients with gain-of-function mutations in LRP5 including Dkk1, which is suppressed by Wnt signaling. It may be that circulating levels of Wnt inhibitors do not reflect changes in target tissues. It is also possible that other mechanisms besides or in addition to resistance in Wnt inhibitors explains the skeletal effects of these mutations.
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Affiliation(s)
- C A Simpson
- Department of Medicine, Section of Endocrinology, Yale School of Medicine, 330 Cedar Street, P.O.Box 208020, New Haven, CT, 06520-8020, USA,
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Liedert A, Röntgen V, Schinke T, Benisch P, Ebert R, Jakob F, Klein-Hitpass L, Lennerz JK, Amling M, Ignatius A. Osteoblast-specific Krm2 overexpression and Lrp5 deficiency have different effects on fracture healing in mice. PLoS One 2014; 9:e103250. [PMID: 25061805 PMCID: PMC4111586 DOI: 10.1371/journal.pone.0103250] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 06/28/2014] [Indexed: 01/09/2023] Open
Abstract
The canonical Wnt/β-catenin pathway plays a key role in the regulation of bone remodeling in mice and humans. Two transmembrane proteins that are involved in decreasing the activity of this pathway by binding to extracellular antagonists, such as Dickkopf 1 (Dkk1), are the low-density lipoprotein receptor related protein 5 (Lrp5) and Kremen 2 (Krm2). Lrp 5 deficiency (Lrp5−/−) as well as osteoblast-specific overexpression of Krm2 in mice (Col1a1-Krm2) result in severe osteoporosis occurring at young age. In this study, we analyzed the influence of Lrp5 deficiency and osteoblast-specific overexpression of Krm2 on fracture healing in mice using flexible and semi-rigid fracture fixation. We demonstrated that fracture healing was highly impaired in both mouse genotypes, but that impairment was more severe in Col1a1-Krm2 than in Lrp5−/− mice and particularly evident in mice in which the more flexible fixation was used. Bone formation was more reduced in Col1a1-Krm2 than in Lrp5−/− mice, whereas osteoclast number was similarly increased in both genotypes in comparison with wild-type mice. Using microarray analysis we identified reduced expression of genes mainly involved in osteogenesis that seemed to be responsible for the observed stronger impairment of healing in Col1a1-Krm2 mice. In line with these findings, we detected decreased expression of sphingomyelin phosphodiesterase 3 (Smpd3) and less active β-catenin in the calli of Col1a1-Krm2 mice. Since Krm2 seems to play a significant role in regulating bone formation during fracture healing, antagonizing KRM2 might be a therapeutic option to improve fracture healing under compromised conditions, such as osteoporosis.
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Affiliation(s)
- Astrid Liedert
- Institute of Orthopaedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Ulm, Germany
- * E-mail:
| | - Viktoria Röntgen
- Institute of Orthopaedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Ulm, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peggy Benisch
- Orthopaedic Center for Musculoskeletal Research, University of Würzburg, Würzburg, Germany
| | - Regina Ebert
- Orthopaedic Center for Musculoskeletal Research, University of Würzburg, Würzburg, Germany
| | - Franz Jakob
- Orthopaedic Center for Musculoskeletal Research, University of Würzburg, Würzburg, Germany
| | | | | | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anita Ignatius
- Institute of Orthopaedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Ulm, Germany
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Rochefort GY. The osteocyte as a therapeutic target in the treatment of osteoporosis. Ther Adv Musculoskelet Dis 2014; 6:79-91. [PMID: 24891879 DOI: 10.1177/1759720x14523500] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Osteoporosis is characterized by a low bone-mineral density associated with skeletal fractures. The decrease in bone-mineral density is the consequence of an unbalanced bone-remodeling process, with higher bone resorption than bone formation. The orchestration of the bone-remodeling process is under the control of the most abundant cell in bone, the osteocyte. Functioning as an endocrine cell, osteocytes are also a source of soluble factors that not only target cells on the bone surface, but also target distant organs. Therefore, any drugs targeting the osteocyte functions and signaling pathways will have a major impact on the bone-remodeling process. This review discusses potential advances in drug therapy for osteoporosis, including novel osteocyte-related antiresorptive and anabolic agents that may become available in the coming years.
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Affiliation(s)
- Gaël Y Rochefort
- EA 2496, Faculté de Chirurgie Dentaire, Université Paris Descartes, 1 rue Maurice Arnoux, 92120 Montrouge, France
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Liedert A, Schinke T, Ignatius A, Amling M. The role of midkine in skeletal remodelling. Br J Pharmacol 2014; 171:870-8. [PMID: 24102259 PMCID: PMC3925025 DOI: 10.1111/bph.12412] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 09/02/2013] [Accepted: 09/09/2013] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Bone tissue is subjected to continuous remodelling, replacing old or damaged bone throughout life. In bone remodelling, the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts ensure the maintenance of bone mass and strength. In early life, the balance of these cellular activities is tightly regulated by various factors, including systemic hormones, the mechanical environment and locally released growth factors. Age-related changes in the activity of these factors in bone remodelling can result in diseases with low bone mass, such as osteoporosis. Osteoporosis is a systemic and age-related skeletal disease characterized by low bone mass and structural degeneration of bone tissue, predisposing the patient to an increased fracture risk. The growth factor midkine (Mdk) plays a key role in bone remodelling and it is expressed during bone formation and fracture repair. Using a mouse deficient in Mdk, our group have identified this protein as a negative regulator of bone formation and mechanically induced bone remodelling. Thus, specific Mdk antagonists might represent a therapeutic option for diseases characterized by low bone mass, such as osteoporosis. LINKED ARTICLES This article is part of a themed section on Midkine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-4.
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Affiliation(s)
- A Liedert
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Ulm, Germany
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35
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Boudin E, Fijalkowski I, Piters E, Van Hul W. The role of extracellular modulators of canonical Wnt signaling in bone metabolism and diseases. Semin Arthritis Rheum 2013; 43:220-40. [DOI: 10.1016/j.semarthrit.2013.01.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/11/2013] [Accepted: 01/16/2013] [Indexed: 12/17/2022]
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Albers J, Keller J, Baranowsky A, Beil FT, Catala-Lehnen P, Schulze J, Amling M, Schinke T. Canonical Wnt signaling inhibits osteoclastogenesis independent of osteoprotegerin. ACTA ACUST UNITED AC 2013; 200:537-49. [PMID: 23401003 PMCID: PMC3575535 DOI: 10.1083/jcb.201207142] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Canonical Wnt signaling through Fzd8 and β-catenin negatively regulates osteoclast differentiation and reduces bone resorption independent of osteoprotegerin. Although Wnt signaling is considered a key regulatory pathway for bone formation, inactivation of β-catenin in osteoblasts does not affect their activity but rather causes increased osteoclastogenesis due to insufficient production of osteoprotegerin (Opg). By monitoring the expression pattern of all known genes encoding Wnt receptors in mouse tissues and bone cells we identified Frizzled 8 (Fzd8) as a candidate regulator of bone remodeling. Fzd8-deficient mice displayed osteopenia with normal bone formation and increased osteoclastogenesis, but this phenotype was not associated with impaired Wnt signaling or Opg production by osteoblasts. The deduced direct negative influence of canonical Wnt signaling on osteoclastogenesis was confirmed in vitro and through the generation of mice lacking β-catenin in the osteoclast lineage. Here, we observed increased bone resorption despite normal Opg production and a resistance to the anti-osteoclastogenic effect of Wnt3a. These results demonstrate that Fzd8 and β-catenin negatively regulate osteoclast differentiation independent of osteoblasts and that canonical Wnt signaling controls bone resorption by two different mechanisms.
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Affiliation(s)
- Joachim Albers
- Department of Osteology and Biomechanics, University Medical Center Hamburg Eppendorf, Hamburg 20246, Germany
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37
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WNT signaling in bone homeostasis and disease: from human mutations to treatments. Nat Med 2013; 19:179-92. [PMID: 23389618 DOI: 10.1038/nm.3074] [Citation(s) in RCA: 1413] [Impact Index Per Article: 128.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/18/2012] [Indexed: 12/11/2022]
Abstract
Low bone mass and strength lead to fragility fractures, for example, in elderly individuals affected by osteoporosis or children with osteogenesis imperfecta. A decade ago, rare human mutations affecting bone negatively (osteoporosis-pseudoglioma syndrome) or positively (high-bone mass phenotype, sclerosteosis and Van Buchem disease) have been identified and found to all reside in components of the canonical WNT signaling machinery. Mouse genetics confirmed the importance of canonical Wnt signaling in the regulation of bone homeostasis, with activation of the pathway leading to increased, and inhibition leading to decreased, bone mass and strength. The importance of WNT signaling for bone has also been highlighted since then in the general population in numerous genome-wide association studies. The pathway is now the target for therapeutic intervention to restore bone strength in millions of patients at risk for fracture. This paper reviews our current understanding of the mechanisms by which WNT signalng regulates bone homeostasis.
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Caverzasio J, Biver E, Thouverey C. Predominant role of PDGF receptor transactivation in Wnt3a-induced osteoblastic cell proliferation. J Bone Miner Res 2013; 28:260-70. [PMID: 22927028 DOI: 10.1002/jbmr.1748] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 08/02/2012] [Accepted: 08/20/2012] [Indexed: 12/17/2022]
Abstract
Previous studies have shown that Wnt3a enhances the proliferation and inhibits the osteogenic differentiation of human mesenchymal stem cells (hMSCs). In this study, we investigated the signaling pathways involved in Wnt3a-induced osteoblastic cell proliferation. Experiments with DKK1, a natural antagonist of Lrp5/6, indicated that Wnt/β-catenin did not play a major role in Wnt3a-induced osteoblastic cell proliferation. The use of selective inhibitors of known mitogenic pathways implicates Src family kinases (SFKs) and a protein kinase C (PKC) in this cellular response. Time-dependent analysis of signaling molecules activated by Wnt3a in MC3T3-E1 cells revealed parallel activation of the canonical pathway and of several tyrosine kinases, including SFKs and PDGF receptors (PDGF-Rs). Functional analysis with specific inhibitors suggested a major role of PDGF-Rs in mediating Wnt3a-induced cell proliferation. Further investigation with an si-RNA approach confirmed a predominant role of this receptor in this cellular response. The use of soluble decoy PDGF-Rs that can sequester extracellular PDGFs excluding that part of the increased PDGF receptor phosphorylation by Wnt3a was the result of autocrine production of PDGFs. A selective SFK inhibitor blunted the enhanced PDGF-R phosphorylation and cell proliferation induced by Wnt3a. Studies of initial events involved in the regulation of this pathway suggest a role of dishevelled. In conclusion, data presented in this study indicate that cell proliferation induced by Wnt3a in osteoblastic cells is mediated by a dishevelled-dependent and β-catenin-independent pathway, which involves the transactivation of PDGF receptors.
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Affiliation(s)
- Joseph Caverzasio
- Service of Bone Diseases, Department of Internal Medicine Specialties, University Hospital of Geneva, Geneva, Switzerland.
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Pasold J, Engelmann R, Keller J, Joost S, Marshall RP, Frerich B, Müller-Hilke B. High bone mass in the STR/ort mouse results from increased bone formation and impaired bone resorption and is associated with extramedullary hematopoiesis. J Bone Miner Metab 2013. [PMID: 23192248 DOI: 10.1007/s00774-012-0394-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We here describe the novel high bone mass phenotype in STR/ort mice that leads to increased bone masses of cortical and trabecular bone and is associated with elevated osteoblast activity and impaired osteoclast function alike. Comparison of STR/ort and C57BL/6 mice reveals an increase in trabecular bone volumes of the vertebrae and at femoral metaphysis. In the females, this difference is significant as early as 2 months of age and at 9 months the females by far exceed their age matched males in all parameters measured. The increase in cortical bone mass at femoral diaphysis results from an apposition to the endosteal surface, it is significant for both sexes as early as 1 month of age and leads to bone marrow compression and extramedullary hematopoiesis. Altered activities of both, the osteoblast and the osteoclast contribute to the high bone mass and collectively this phenotype supports a multifactorial pathogenesis. Moreover, the spontaneous development of osteoarthritis in male STR/ort mice is suggestive of a tight correlation between trabecular bone mass and the development of degenerative changes of the articular cartilage.
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Affiliation(s)
- Juliane Pasold
- Institute of Immunology, University of Rostock, Schillingallee 68, 18057, Rostock, Germany
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Joiner DM, Ke J, Zhong Z, Xu HE, Williams BO. LRP5 and LRP6 in development and disease. Trends Endocrinol Metab 2013; 24:31-9. [PMID: 23245947 PMCID: PMC3592934 DOI: 10.1016/j.tem.2012.10.003] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 10/09/2012] [Accepted: 10/15/2012] [Indexed: 11/21/2022]
Abstract
Low-density lipoprotein-related receptors 5 and 6 (LRP5/6) are highly homologous proteins with key functions in canonical Wnt signaling. Alterations in the genes encoding these receptors or their interacting proteins are linked to human diseases, and as such they have been a major focus of drug development efforts to treat several human conditions including osteoporosis, cancer, and metabolic disease. Here, we discuss the links between alterations in LRP5/6 and disease, proteins that interact with them, and insights gained into their function from mouse models. We also highlight current drug development related to LRP5/6 as well as how the recent elucidation of their crystal structures may allow further refinement of our ability to target them for therapeutic benefit.
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Affiliation(s)
- Danese M. Joiner
- Center for Skeletal Disease Research, Laboratory of Cell Signaling and Carcinogenesis, Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, USA
| | - Jiyuan Ke
- Center for Structural Biology and Drug Discovery, Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, USA
| | - Zhendong Zhong
- Center for Skeletal Disease Research, Laboratory of Cell Signaling and Carcinogenesis, Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, USA
| | - H. Eric Xu
- Center for Structural Biology and Drug Discovery, Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, USA
| | - Bart O. Williams
- Center for Skeletal Disease Research, Laboratory of Cell Signaling and Carcinogenesis, Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, USA
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Regard JB, Zhong Z, Williams BO, Yang Y. Wnt signaling in bone development and disease: making stronger bone with Wnts. Cold Spring Harb Perspect Biol 2012; 4:4/12/a007997. [PMID: 23209148 DOI: 10.1101/cshperspect.a007997] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The skeleton as an organ is widely distributed throughout the entire vertebrate body. Wnt signaling has emerged to play major roles in almost all aspects of skeletal development and homeostasis. Because abnormal Wnt signaling causes various human skeletal diseases, Wnt signaling has become a focal point of intensive studies in skeletal development and disease. As a result, promising effective therapeutic agents for bone diseases are being developed by targeting the Wnt signaling pathway. Understanding the functional mechanisms of Wnt signaling in skeletal biology and diseases highlights how basic and clinical studies can stimulate each other to push a quick and productive advancement of the entire field. Here we review the current understanding of Wnt signaling in critical aspects of skeletal biology such as bone development, remodeling, mechanotransduction, and fracture healing. We took special efforts to place fundamentally important discoveries in the context of human skeletal diseases.
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Affiliation(s)
- Jean B Regard
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Ke HZ, Richards WG, Li X, Ominsky MS. Sclerostin and Dickkopf-1 as therapeutic targets in bone diseases. Endocr Rev 2012; 33:747-83. [PMID: 22723594 DOI: 10.1210/er.2011-1060] [Citation(s) in RCA: 282] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The processes of bone growth, modeling, and remodeling determine the structure, mass, and biomechanical properties of the skeleton. Dysregulated bone resorption or bone formation may lead to metabolic bone diseases. The Wnt pathway plays an important role in bone formation and regeneration, and expression of two Wnt pathway inhibitors, sclerostin and Dickkopf-1 (DKK1), appears to be associated with changes in bone mass. Inactivation of sclerostin leads to substantially increased bone mass in humans and in genetically manipulated animals. Studies in various animal models of bone disease have shown that inhibition of sclerostin using a monoclonal antibody (Scl-Ab) increases bone formation, density, and strength. Additional studies show that Scl-Ab improves bone healing in models of bone repair. Inhibition of DKK1 by monoclonal antibody (DKK1-Ab) stimulates bone formation in younger animals and to a lesser extent in adult animals and enhances fracture healing. Thus, sclerostin and DKK1 are emerging as the leading new targets for anabolic therapies to treat bone diseases such as osteoporosis and for bone repair. Clinical trials are ongoing to evaluate the effects of Scl-Ab and DKK1-Ab in humans for the treatment of bone loss and for bone repair.
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Affiliation(s)
- Hua Zhu Ke
- Metabolic Disorders Research, Amgen Inc., One Amgen Center Drive, MS 29-M-B, Thousand Oaks, California 91320, USA.
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Benisch P, Schilling T, Klein-Hitpass L, Frey SP, Seefried L, Raaijmakers N, Krug M, Regensburger M, Zeck S, Schinke T, Amling M, Ebert R, Jakob F. The transcriptional profile of mesenchymal stem cell populations in primary osteoporosis is distinct and shows overexpression of osteogenic inhibitors. PLoS One 2012; 7:e45142. [PMID: 23028809 PMCID: PMC3454401 DOI: 10.1371/journal.pone.0045142] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/13/2012] [Indexed: 12/11/2022] Open
Abstract
Primary osteoporosis is an age-related disease characterized by an imbalance in bone homeostasis. While the resorptive aspect of the disease has been studied intensely, less is known about the anabolic part of the syndrome or presumptive deficiencies in bone regeneration. Multipotent mesenchymal stem cells (MSC) are the primary source of osteogenic regeneration. In the present study we aimed to unravel whether MSC biology is directly involved in the pathophysiology of the disease and therefore performed microarray analyses of hMSC of elderly patients (79–94 years old) suffering from osteoporosis (hMSC-OP). In comparison to age-matched controls we detected profound changes in the transcriptome in hMSC-OP, e.g. enhanced mRNA expression of known osteoporosis-associated genes (LRP5, RUNX2, COL1A1) and of genes involved in osteoclastogenesis (CSF1, PTH1R), but most notably of genes coding for inhibitors of WNT and BMP signaling, such as Sclerostin and MAB21L2. These candidate genes indicate intrinsic deficiencies in self-renewal and differentiation potential in osteoporotic stem cells. We also compared both hMSC-OP and non-osteoporotic hMSC-old of elderly donors to hMSC of ∼30 years younger donors and found that the transcriptional changes acquired between the sixth and the ninth decade of life differed widely between osteoporotic and non-osteoporotic stem cells. In addition, we compared the osteoporotic transcriptome to long term-cultivated, senescent hMSC and detected some signs for pre-senescence in hMSC-OP. Our results suggest that in primary osteoporosis the transcriptomes of hMSC populations show distinct signatures and little overlap with non-osteoporotic aging, although we detected some hints for senescence-associated changes. While there are remarkable inter-individual variations as expected for polygenetic diseases, we could identify many susceptibility genes for osteoporosis known from genetic studies. We also found new candidates, e.g. MAB21L2, a novel repressor of BMP-induced transcription. Such transcriptional changes may reflect epigenetic changes, which are part of a specific osteoporosis-associated aging process.
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Affiliation(s)
- Peggy Benisch
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Tatjana Schilling
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Ludger Klein-Hitpass
- Institute of Cell Biology (Tumor Research), University Hospital Essen, Essen, Germany
| | - Sönke P. Frey
- Department of Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Wuerzburg, Wuerzburg, Germany
| | - Lothar Seefried
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Nadja Raaijmakers
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Melanie Krug
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Martina Regensburger
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Sabine Zeck
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Regina Ebert
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Franz Jakob
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
- * E-mail:
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Ablation of the pro-apoptotic protein Bax protects mice from glucocorticoid-induced bone growth impairment. PLoS One 2012; 7:e33168. [PMID: 22442678 PMCID: PMC3307731 DOI: 10.1371/journal.pone.0033168] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 02/10/2012] [Indexed: 12/23/2022] Open
Abstract
Dexamethasone (Dexa) is a widely used glucocorticoid to treat inflammatory diseases; however, a multitude of undesired effects have been reported to arise from this treatment including osteoporosis, obesity, and in children decreased longitudinal bone growth. We and others have previously shown that glucocorticoids induce apoptosis in growth plate chondrocytes. Here, we hypothesized that Bax, a pro-apoptotic member of the Bcl-2 family, plays a key role in Dexa-induced chondrocyte apoptosis and bone growth impairment. Indeed, experiments in the human HCS-2/8 chondrocytic cell line demonstrated that silencing of Bax expression using small-interfering (si) RNA efficiently blocked Dexa-induced apoptosis. Furthermore, ablation of Bax in female mice protected against Dexa-induced bone growth impairment. Finally, Bax activation by Dexa was confirmed in human growth plate cartilage specimens cultured ex vivo. Our findings could therefore open the door for new therapeutic approaches to prevent glucocorticoid-induced bone growth impairment through specific targeting of Bax.
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Anastasilakis AD, Polyzos SA, Toulis KA. Role of wingless tail signaling pathway in osteoporosis: an update of current knowledge. Curr Opin Endocrinol Diabetes Obes 2011; 18:383-8. [PMID: 21897222 DOI: 10.1097/med.0b013e32834afff2] [Citation(s) in RCA: 256] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW Wingless tail (Wnt) pathway is crucial for osteoblast activation and action. This review summarizes the evidence published during the previous year on the emerging role of Wnt signaling alterations in the pathogenesis, diagnosis, and potential therapeutic approaches of osteoporosis. RECENT FINDINGS New insights into the mechanisms regulating Wnt/β-catenin canonical pathway, including the role of Kremen-2 receptor, lamin A/C protein, periostin, and pleiotropin in bone physiology, the crosstalk between the RUNX-2 transcription-factor cascade and the Wnt pathway, and the concept that individual Wnt ligands may have a unique and distinct mission in bone milieu, are presented. Nutritional habits may affect Wnt signaling in bone. Serum sclerostin and dickkopf-1 levels may serve as markers of bone metabolism and disease, although further standardization methods are required. Finally, the effect of current antiosteoporotic treatments on Wnt signaling is discussed, as well as the therapeutic potential of drugs targeting either Wnt signaling amplification or Wnt antagonists' attenuation. SUMMARY Although Wnt pathway is currently a field of thorough investigation, it is still far from been fully elucidated. Understanding its complex pathophysiology has evoked promising therapeutic approaches for osteoporosis. However, given that Wnt signaling is crucial for many tissues, emerging knowledge should be cautiously translated in therapeutics.
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Affiliation(s)
- Athanasios D Anastasilakis
- Department of Endocrinology, 424 General Military Hospital, Second Medical Clinic, Medical School, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece.
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Keller J, Catala-Lehnen P, Wintges K, Schulze J, Bickert T, Ito W, Horst AK, Amling M, Schinke T. Transgenic over-expression of interleukin-33 in osteoblasts results in decreased osteoclastogenesis. Biochem Biophys Res Commun 2011; 417:217-22. [PMID: 22142849 DOI: 10.1016/j.bbrc.2011.11.088] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 11/17/2011] [Indexed: 10/15/2022]
Abstract
Interleukin-33 (IL-33) is the most recently identified member of the IL-1 family of cytokines, which is primarily known for its proinflammatory functions. We have previously reported that IL-33 is expressed by bone-forming osteoblasts, and that administration of recombinant IL-33 to bone marrow cultures inhibits their differentiation into bone-resorbing osteoclasts. Likewise, while the inhibitory effect of IL-33 on osteoclast differentiation was fully abolished in cultures lacking the IL-33 receptor ST2, mice lacking ST2 displayed low bone mass caused by increased osteoclastogenesis. Although these data suggested a physiological role of IL-33 as an inhibitor of bone resorption, direct in vivo evidence supporting such a function was still missing. Here we describe the generation and bone histomorphometric analysis of a transgenic mouse model (Col1a1-Il33) over-expressing IL-33 specifically in osteoblasts. While we did not observe differences in osteoblast number and bone formation between wildtype and Col1a1-Il33 mice, the number of osteoclasts was significantly reduced compared to wildtype littermates in two independent transgenic lines. Since we did not observe quantitative differences in the populations of eosinophils, neutrophils, basophils or M2-macrophages from the bone marrow of wildtype and Col1a1-Il33 mice, our data demonstrate that an inhibition of osteoclastogenesis is one of the major physiological functions of IL-33, at least in mice.
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Affiliation(s)
- Johannes Keller
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Update on Wnt signaling in bone cell biology and bone disease. Gene 2011; 492:1-18. [PMID: 22079544 DOI: 10.1016/j.gene.2011.10.044] [Citation(s) in RCA: 288] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/13/2011] [Accepted: 10/20/2011] [Indexed: 12/17/2022]
Abstract
For more than a decade, Wnt signaling pathways have been the focus of intense research activity in bone biology laboratories because of their importance in skeletal development, bone mass maintenance, and therapeutic potential for regenerative medicine. It is evident that even subtle alterations in the intensity, amplitude, location, and duration of Wnt signaling pathways affects skeletal development, as well as bone remodeling, regeneration, and repair during a lifespan. Here we review recent advances and discrepancies in how Wnt/Lrp5 signaling regulates osteoblasts and osteocytes, introduce new players in Wnt signaling pathways that have important roles in bone development, discuss emerging areas such as the role of Wnt signaling in osteoclastogenesis, and summarize progress made in translating basic studies to clinical therapeutics and diagnostics centered around inhibiting Wnt pathway antagonists, such as sclerostin, Dkk1 and Sfrp1. Emphasis is placed on the plethora of genetic studies in mouse models and genome wide association studies that reveal the requirement for and crucial roles of Wnt pathway components during skeletal development and disease.
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Albers J, Schulze J, Beil FT, Gebauer M, Baranowsky A, Keller J, Marshall RP, Wintges K, Friedrich FW, Priemel M, Schilling AF, Rueger JM, Cornils K, Fehse B, Streichert T, Sauter G, Jakob F, Insogna KL, Pober B, Knobeloch KP, Francke U, Amling M, Schinke T. Control of bone formation by the serpentine receptor Frizzled-9. ACTA ACUST UNITED AC 2011; 192:1057-72. [PMID: 21402791 PMCID: PMC3063134 DOI: 10.1083/jcb.201008012] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Although Wnt signaling in osteoblasts is of critical importance for the regulation of bone remodeling, it is not yet known which specific Wnt receptors of the Frizzled family are functionally relevant in this process. In this paper, we show that Fzd9 is induced upon osteoblast differentiation and that Fzd9(-/-) mice display low bone mass caused by impaired bone formation. Our analysis of Fzd9(-/-) primary osteoblasts demonstrated defects in matrix mineralization in spite of normal expression of established differentiation markers. In contrast, we observed a reduced expression of chemokines and interferon-regulated genes in Fzd9(-/-) osteoblasts. We also identified the ubiquitin-like modifier Isg15 as one potential downstream mediator of Fzd9 in these cells. Importantly, our molecular analysis further revealed that canonical Wnt signaling is not impaired in the absence of Fzd9, thus explaining the absence of a bone resorption phenotype. Collectively, our results reveal a previously unknown function of Fzd9 in osteoblasts, a finding that may have therapeutic implications for bone loss disorders.
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Affiliation(s)
- Joachim Albers
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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Dkk1 stabilizes Wnt co-receptor LRP6: implication for Wnt ligand-induced LRP6 down-regulation. PLoS One 2010; 5:e11014. [PMID: 20543981 PMCID: PMC2882367 DOI: 10.1371/journal.pone.0011014] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 05/16/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The low density lipoprotein receptor-related protein-6 (LRP6) is an essential co-receptor for canonical Wnt signaling. Dickkopf 1 (Dkk1), a major secreted Wnt signaling antagonist, binds to LRP6 with high affinity and prevents the Frizzled-Wnt-LRP6 complex formation in response to Wnts. Previous studies have demonstrated that Dkk1 promotes LRP6 internalization and degradation when it forms a ternary complex with the cell surface receptor Kremen. METHODOLOGY/PRINCIPAL FINDINGS In the present study, we found that transfected Dkk1 induces LRP6 accumulation while inhibiting Wnt/LRP6 signaling. Treatment with Dkk1-conditioned medium or recombinant Dkk1 protein stabilized LRP6 with a prolonged half-life and induces LRP6 accumulation both at the cell surface and in endosomes. We also demonstrated that Kremen2 co-expression abrogated the effect of Dkk1 on LRP6 accumulation, indicating that the effect of Kremen2 is dominant over Dkk1 regulation of LRP6. Furthermore, we found that Wnt3A treatment induces LRP6 down-regulation, an effect paralleled with a Wnt/LRP6 signaling decay, and that Dkk1 treatment blocked Wnt3A-induced LRP6 down-regulation. Finally, we found that LRP6 turnover was blocked by an inhibitor of caveolae-mediated endocytosis. CONCLUSIONS/SIGNIFICANCE Our results reveal a novel role for Dkk1 in preventing Wnt ligand-induced LRP6 down-regulation and contribute significantly to our understanding of Dkk1 function in Wnt/LRP6 signaling.
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