1
|
Ko FC, Moran MM, Ross RD, Sumner DR. Activation of canonical Wnt signaling accelerates intramembranous bone regeneration in male mice. J Orthop Res 2022; 40:1834-1843. [PMID: 34811780 PMCID: PMC9124233 DOI: 10.1002/jor.25217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 10/25/2021] [Accepted: 11/09/2021] [Indexed: 02/04/2023]
Abstract
Canonical Wnt signaling plays an important role in skeletal development, homeostasis, and both endochondral and intramembranous repair. While studies have demonstrated that the inhibition of Wnt signaling impairs intramembranous bone regeneration, how its activation affects intramembranous bone regeneration has been underexplored. Therefore, we sought to determine the effects of activation of canonical Wnt signaling on intramembranous bone regeneration by using the well-established marrow ablation model. We hypothesized that mice with a mutation in the Wnt ligand coreceptor gene Lrp5 would have accelerated intramembranous bone regeneration. Male and female wild-type and Lrp5-mutant mice underwent unilateral femoral bone marrow ablation surgery in the right femur at 4 weeks of age. Both the left intact and right operated femurs were assessed at Days 3, 5, 7, 10, and 14. The intact femur of Lrp5 mutant mice of both sexes had higher bone mass than wild-type littermates, although to a greater degree in males than females. Overall, the regenerated bone volume in Lrp5 mutant male mice was 1.8-fold higher than that of littermate controls, whereas no changes were observed between female Lrp5 mutant and littermate control mice. In addition, the rate of intramembranous bone regeneration (from Day 3 to Day 7) was higher in Lrp5 mutant male mice compared to their same-sex littermate controls with no difference in the females. Thus, activation of canonical Wnt signaling increases bone mass in intact bones of both sexes, but accelerates intramembranous bone regeneration following an injury challenge only in male mice.
Collapse
Affiliation(s)
- Frank C. Ko
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, 60612,Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, 60612
| | - Meghan M. Moran
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, 60612,Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, 60612
| | - Ryan D. Ross
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, 60612,Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, 60612
| | - D. Rick Sumner
- Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL, 60612,Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, 60612
| |
Collapse
|
2
|
Witcher PC, Miner SE, Horan DJ, Bullock WA, Lim KE, Kang KS, Adaniya AL, Ross RD, Loots GG, Robling AG. Sclerostin neutralization unleashes the osteoanabolic effects of Dkk1 inhibition. JCI Insight 2018; 3:98673. [PMID: 29875318 DOI: 10.1172/jci.insight.98673] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/26/2018] [Indexed: 12/12/2022] Open
Abstract
The WNT pathway has become an attractive target for skeletal therapies. High-bone-mass phenotypes in patients with loss-of-function mutations in the LRP5/6 inhibitor Sost (sclerosteosis), or in its downstream enhancer region (van Buchem disease), highlight the utility of targeting Sost/sclerostin to improve bone properties. Sclerostin-neutralizing antibody is highly osteoanabolic in animal models and in human clinical trials, but antibody-based inhibition of another potent LRP5/6 antagonist, Dkk1, is largely inefficacious for building bone in the unperturbed adult skeleton. Here, we show that conditional deletion of Dkk1 from bone also has negligible effects on bone mass. Dkk1 inhibition increases Sost expression, suggesting a potential compensatory mechanism that might explain why Dkk1 suppression lacks anabolic action. To test this concept, we deleted Sost from osteocytes in, or administered sclerostin neutralizing antibody to, mice with a Dkk1-deficient skeleton. A robust anabolic response to Dkk1 deletion was manifest only when Sost/sclerostin was impaired. Whole-body DXA scans, μCT measurements of the femur and spine, histomorphometric measures of femoral bone formation rates, and biomechanical properties of whole bones confirmed the anabolic potential of Dkk1 inhibition in the absence of sclerostin. Further, combined administration of sclerostin and Dkk1 antibody in WT mice produced a synergistic effect on bone gain that greatly exceeded individual or additive effects of the therapies, confirming the therapeutic potential of inhibiting multiple WNT antagonists for skeletal health. In conclusion, the osteoanabolic effects of Dkk1 inhibition can be realized if sclerostin upregulation is prevented. Anabolic therapies for patients with low bone mass might benefit from a strategy that accounts for the compensatory milieu of WNT inhibitors in bone tissue.
Collapse
Affiliation(s)
- Phillip C Witcher
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sara E Miner
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Daniel J Horan
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Whitney A Bullock
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Kyung-Eun Lim
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Kyung Shin Kang
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Physical Sciences & Engineering, Anderson University, Anderson, Indiana, USA
| | - Alison L Adaniya
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ryan D Ross
- Department of Cell & Molecular Medicine, Rush University Medical Center, Chicago, Illinois, USA
| | - Gabriela G Loots
- Biology and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, California, USA.,School of Natural Sciences, University of California, Merced, California, USA
| | - Alexander G Robling
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, USA.,Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, USA.,Indiana Center for Musculoskeletal Health, Indianapolis, Indiana, USA
| |
Collapse
|
3
|
Roetzer KM, Uyanik G, Brehm A, Zwerina J, Zandieh S, Czech T, Roschger P, Misof BM, Klaushofer K. Novel familial mutation of LRP5 causing high bone mass: Genetic analysis, clinical presentation, and characterization of bone matrix mineralization. Bone 2018; 107:154-160. [PMID: 29208525 DOI: 10.1016/j.bone.2017.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 12/01/2017] [Accepted: 12/01/2017] [Indexed: 12/29/2022]
Abstract
The Wnt signalling pathway is a critical regulator of bone mass and quality. Several heterozygous mutations in the LRP5 gene, a Wnt co-receptor, causing high bone mass (LRP5-HBM) have been described to date. The pathogenic mechanism is thought to be a gain-of-function caused by impaired inhibition of the canonical Wnt signalling pathway, thereby leading to increased bone formation. We report the cases of two affected family members, a 53-year-old mother and her 23-year-old daughter, with high bone mass (T-scores mother: lumbar spine 11.4, femoral neck 10.5; T-scores daughter: lumbar spine 5.4, femoral neck 8.7), increased calvarial thickness, and thickened cortices of the long bones but no history of fractures. Whereas the mother did not show any indications of the mutation, the daughter suffered from congenital hearing impairment resulting in cochlear implantation, recurrent facial palsy, and migraine. In addition, she had stenosis of the foramen magnum. In both individuals, we detected a novel heterozygous duplication of six basepairs in the LRP5 gene, resulting in an insertion of two amino acids, very likely associated with a gain-of-function. When the daughter had part of the occipital bone surgically removed, the bone sample was used for the visualization of bone lamellar structure and bone cells as well as the measurement of bone mineralization density distribution (BMDD). The bone sample revealed two distinctly different regions: an intra-cortical region with osteonal remodeling, typical osteonal lamellar orientation, associated with relatively higher heterogeneity of bone matrix mineralization, and another periosteal region devoid of bone remodeling, with parallel bone lamellae and lower heterogeneity of mineralization. In conclusion, we present data on bone tissue and material level from an LRP5-HBM patient with a novel mutation in the LRP5 gene. Our findings indicate normal morphology of osteoclasts and osteoblasts as well as normal mineralization in skull bone in LRP5-HBM.
Collapse
Affiliation(s)
- K M Roetzer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Center for Medical Genetics, Hanusch Hospital, Vienna, Austria; Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - G Uyanik
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Center for Medical Genetics, Hanusch Hospital, Vienna, Austria; Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - A Brehm
- 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - J Zwerina
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - S Zandieh
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Department of Radiology and Nuclear Medicine, Hanusch Hospital, Vienna, Austria
| | - T Czech
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - B M Misof
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria.
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; 1st Medical Department, Hanusch Hospital, Vienna, Austria
| |
Collapse
|
4
|
Boudin E, Yorgan T, Fijalkowski I, Sonntag S, Steenackers E, Hendrickx G, Peeters S, De Maré A, Vervaet B, Verhulst A, Mortier G, D'Haese P, Schinke T, Van Hul W. The Lrp4R1170Q Homozygous Knock-In Mouse Recapitulates the Bone Phenotype of Sclerosteosis in Humans. J Bone Miner Res 2017; 32:1739-1749. [PMID: 28477420 DOI: 10.1002/jbmr.3160] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/13/2017] [Accepted: 04/22/2017] [Indexed: 01/08/2023]
Abstract
Sclerosteosis is a rare autosomal recessive bone disorder marked by hyperostosis of the skull and tubular bones. Initially, we and others reported that sclerosteosis was caused by loss-of-function mutations in SOST, encoding sclerostin. More recently, we identified disease-causing mutations in LRP4, a binding partner of sclerostin, in three sclerosteosis patients. Upon binding to sclerostin, LRP4 can inhibit the canonical WNT signaling that is known to be an important pathway in the regulation of bone formation. To further investigate the role of LRP4 in the bone formation process, we generated an Lrp4 mutated sclerosteosis mouse model by introducing the p.Arg1170Gln mutation in the mouse genome. Extensive analysis of the bone phenotype of the Lrp4R1170Q/R1170Q knock-in (KI) mouse showed the presence of increased trabecular and cortical bone mass as a consequence of increased bone formation by the osteoblasts. In addition, three-point bending analysis also showed that the increased bone mass results in increased bone strength. In contrast to the human sclerosteosis phenotype, we could not observe syndactyly in the forelimbs or hindlimbs of the Lrp4 KI animals. Finally, we could not detect any significant changes in the bone formation and resorption markers in the serum of the mutant mice. However, the serum sclerostin levels were strongly increased and the level of sclerostin in the tibia was decreased in Lrp4R1170Q/R1170Q mice, confirming the role of LRP4 as an anchor for sclerostin in bone. In conclusion, the Lrp4R1170Q/R1170Q mouse is a good model for the human sclerosteosis phenotype caused by mutations in LRP4 and can be used in the future for further investigation of the mechanism whereby LRP4 regulates bone formation. © 2017 American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Eveline Boudin
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Timur Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Igor Fijalkowski
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | | | - Ellen Steenackers
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Gretl Hendrickx
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Silke Peeters
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Annelies De Maré
- Laboratory of Pathophysiology, Department Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Benjamin Vervaet
- Laboratory of Pathophysiology, Department Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Anja Verhulst
- Laboratory of Pathophysiology, Department Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Geert Mortier
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Patrick D'Haese
- Laboratory of Pathophysiology, Department Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Wim Van Hul
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| |
Collapse
|