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Misof BM, Fratzl-Zelman N. Bone Quality and Mineralization and Effects of Treatment in Osteogenesis Imperfecta. Calcif Tissue Int 2024:10.1007/s00223-024-01263-8. [PMID: 39231826 DOI: 10.1007/s00223-024-01263-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 07/10/2024] [Indexed: 09/06/2024]
Abstract
Osteogenesis imperfecta (OI) is a rare congenital bone dysplasia characterized by high fracture rates and broad variations in clinical manifestations ranging from mild to increasingly severe and perinatal lethal forms. The underlying mutations affect either the synthesis or processing of the type I procollagen molecule itself or proteins that are involved in the formation and mineralization of the collagen matrix. Consequently, the collagen forming cells, the osteoblasts, become broadly dysfunctional in OI. Strikingly, hypermineralized bone matrix seems to be a frequent feature in OI, despite the variability in clinical severity and mutations in the so far studied different forms of human OI. While the causes of the increased mineral content of the bone matrix are not fully understood yet, there is evidence that the descendants of the osteoblasts, the osteocytes, which play a critical role not only in bone remodeling, but also in mineralization and sensing of mechanical loads, are also highly dysregulated and might be of major importance in the pathogenesis of OI. In this review article, we firstly summarize findings of cellular abnormalities in osteoblasts and osteocytes, alterations of the organic matrix, as well as of the microstructural organization of bone. Secondly, we focus on the hypermineralization of the bone matrix in OI as observed in several different forms of human OI as well as in animal models, its measurement and potential mechanical implications and its effect on the bone mineral density measured by dual X-ray absorptiometry. Thirdly, we give an overview of established medication treatments of OI and new approaches with a focus of their known or possible effects on the bone material, particularly on bone matrix mineralization.
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Affiliation(s)
- Barbara M Misof
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria.
- Vienna Bone and Growth Center, Vienna, Austria.
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2
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Jovanovic M, Marini JC. Update on the Genetics of Osteogenesis Imperfecta. Calcif Tissue Int 2024:10.1007/s00223-024-01266-5. [PMID: 39127989 DOI: 10.1007/s00223-024-01266-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 07/22/2024] [Indexed: 08/12/2024]
Abstract
Osteogenesis imperfecta (OI) is a heterogeneous heritable skeletal dysplasia characterized by bone fragility and deformity, growth deficiency, and other secondary connective tissue defects. OI is now understood as a collagen-related disorder caused by defects of genes whose protein products interact with collagen for folding, post-translational modification, processing and trafficking, affecting bone mineralization and osteoblast differentiation. This review provides the latest updates on genetics of OI, including new developments in both dominant and rare OI forms, as well as the signaling pathways involved in OI pathophysiology. There is a special emphasis on discoveries of recessive mutations in TENT5A, MESD, KDELR2 and CCDC134 whose causality of OI types XIX, XX, XXI and XXI, respectively, is now established and expends the complexity of mechanisms underlying OI to overlap LRP5/6 and MAPK/ERK pathways. We also review in detail new discoveries connecting the known OI types to each other, which may underlie an eventual understanding of a final common pathway in OI cellular and bone biology.
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Affiliation(s)
- Milena Jovanovic
- Section on Heritable Disorders of Bone and Extracellular Matrix, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Section on Adolescent Bone and Body Composition, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Joan C Marini
- Section on Heritable Disorders of Bone and Extracellular Matrix, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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3
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Salama MA, Anwar Ismail A, Islam MS, K. G. AR, Al Kawas S, Samsudin AR, A. C. SA. Impact of Bone Morphogenetic Protein 7 and Prostaglandin receptors on osteoblast healing and organization of collagen. PLoS One 2024; 19:e0303202. [PMID: 38753641 PMCID: PMC11098345 DOI: 10.1371/journal.pone.0303202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/19/2024] [Indexed: 05/18/2024] Open
Abstract
PURPOSE This study seeks to investigate the impact of co-administering either a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist alone with a low dose BMP7 on in vitro healing process, collagen content and maturation of human osteoblasts. METHODOLOGY Human osteoblast cells were used in this study. These cells were cultured and subjected to different concentrations of Prostaglandin EP2 receptor agonist, EP1 receptor antagonist, BMP7, Control (Ct) (Vehicle alone), and various combinations treatments. Cell viability at 24, 48 and 72 hours (h) was evaluated using the XTT assay. A wound healing assay was conducted to observe the migration ability of human osteoblast cells. Additionally, Sirius red staining and Fourier-Transform Infrared Spectroscopy Imaging (FT-IR) was employed to analyze various parameters, including total protein concentration, collagen production, mature collagen concentration, and mineral content. RESULTS The combination of low dose BMP7 and Prostaglandin EP2 receptor agonist resulted to the lowest cell viability when compared to both the Ct and individual treatments. In contrast, the Prostaglandin EP1 receptor antagonist alone showed the highest cellular viability at 72 h. In the wound healing assay, the combined treatment of low dose BMP7 with the Prostaglandin EP2 receptor agonist and EP1 receptor antagonist showed a decrease in human osteoblast healing after 24 h. Analysis of FT-IR data indicated a reduction in total protein content, collagen maturity, collagen concentration and mineral content in combination treatment compared to the single or Ct treatments. CONCLUSION The combination of a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist when combined with low dose BMP7 significantly hinders both human osteoblast healing and collagen maturity/concentration in comparison to low dose BMP7 treatment alone.
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Affiliation(s)
- Mohammad Ali Salama
- Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Asmaa Anwar Ismail
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Md Sofiqul Islam
- Department of Operative Dentistry, RAK College of Dental Sciences, RAK Medical and Health Sciences University, Ras Al Khaimah, United Arab Emirates
| | - Aghila Rani K. G.
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Sausan Al Kawas
- Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - A. R. Samsudin
- Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Smriti Aryal A. C.
- Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates
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4
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Sun Y, Li L, Wang J, Liu H, Wang H. Emerging Landscape of Osteogenesis Imperfecta Pathogenesis and Therapeutic Approaches. ACS Pharmacol Transl Sci 2024; 7:72-96. [PMID: 38230285 PMCID: PMC10789133 DOI: 10.1021/acsptsci.3c00324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 12/10/2023] [Accepted: 12/12/2023] [Indexed: 01/18/2024]
Abstract
Osteogenesis imperfecta (OI) is an uncommon genetic disorder characterized by shortness of stature, hearing loss, poor bone mass, recurrent fractures, and skeletal abnormalities. Pathogenic variations have been found in over 20 distinct genes that are involved in the pathophysiology of OI, contributing to the disorder's clinical and genetic variability. Although medications, surgical procedures, and other interventions can partially alleviate certain symptoms, there is still no known cure for OI. In this Review, we provide a comprehensive overview of genetic pathogenesis, existing treatment modalities, and new developments in biotechnologies such as gene editing, stem cell reprogramming, functional differentiation, and transplantation for potential future OI therapy.
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Affiliation(s)
- Yu Sun
- PET
Center, Chongqing University Three Gorges
Hospital, Chongqing 404000, China
| | - Lin Li
- PET
Center, Chongqing University Three Gorges
Hospital, Chongqing 404000, China
| | - Jiajun Wang
- Medical
School of Hubei Minzu University, Enshi 445000, China
| | - Huiting Liu
- PET
Center, Chongqing University Three Gorges
Hospital, Chongqing 404000, China
| | - Hu Wang
- Department
of Neurology, Johns Hopkins University School
of Medicine, Baltimore, Maryland 21205, United States
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Raimann A, Misof BM, Fratzl P, Fratzl-Zelman N. Bone Material Properties in Bone Diseases Affecting Children. Curr Osteoporos Rep 2023; 21:787-805. [PMID: 37897675 DOI: 10.1007/s11914-023-00822-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/12/2023] [Indexed: 10/30/2023]
Abstract
PURPOSE OF REVIEW Metabolic and genetic bone disorders affect not only bone mass but often also the bone material, including degree of mineralization, matrix organization, and lacunar porosity. The quality of juvenile bone is moreover highly influenced by skeletal growth. This review aims to provide a compact summary of the present knowledge on the complex interplay between bone modeling and remodeling during skeletal growth and to alert the reader to the complexity of bone tissue characteristics in children with bone disorders. RECENT FINDINGS We describe cellular events together with the characteristics of the different tissues and organic matrix organization (cartilage, woven and lamellar bone) occurring during linear growth. Subsequently, we present typical alterations thereof in disorders leading to over-mineralized bone matrix compared to those associated with low or normal mineral content based on bone biopsy studies. Growth spurts or growth retardation might amplify or mask disease-related alterations in bone material, which makes the interpretation of bone tissue findings in children complex and challenging.
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Affiliation(s)
- Adalbert Raimann
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University of Vienna, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Barbara M Misof
- Vienna Bone and Growth Center, Vienna, Austria
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Research Campus Golm, Potsdam, Germany
| | - Nadja Fratzl-Zelman
- Vienna Bone and Growth Center, Vienna, Austria.
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria.
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Singh N, Hansdah K, Bouzid A, Ray CS, Desai A, Panda KC, Choudhury JC, Tekari A, Masmoudi S, Ramchander PV. Genetic variants and altered expression of SERPINF1 confer disease susceptibility in patients with otosclerosis. J Hum Genet 2023; 68:635-642. [PMID: 37308566 DOI: 10.1038/s10038-023-01158-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/27/2023] [Accepted: 04/27/2023] [Indexed: 06/14/2023]
Abstract
Otosclerosis (OTSC) is a focal and diffuse bone disorder of the human middle ear characterized by abnormal bone growth and deposition at the stapes' footplate. This hinders the transmission of acoustic waves to the inner ear leading to subsequent conductive hearing loss. The plausible convections for the disease are genetic and environmental factors with yet an unraveled root cause. Recently, exome sequencing of European individuals with OTSC revealed rare pathogenic variants in the Serpin Peptidase Inhibitor, Clade F (SERPINF1) gene. Here, we sought to investigate the causal variants of SERPINF1 in the Indian population. The gene and protein expression was also evaluated in otosclerotic stapes to ameliorate our understanding of the potential effect of this gene in OTSC. A total of 230 OTSC patients and 230 healthy controls were genotyped by single-strand conformational polymorphism and Sanger sequencing methods. By comparing the case controls, we identified five rare variants (c.72 C > T, c.151 G > A, c.242 C > G, c.823 A > T, and c.826 T > A) only in patients. Four variants c.390 T > C (p = 0.048), c.440-39 C > T (p = 0.007), c.643 + 9 G > A (p = 0.035), and c.643 + 82 T > C (p = 0.005) were found to be significantly associated with the disease. Down-regulation of SERPINF1 transcript level in otosclerotic stapes was quantified by qRT-PCR, ddPCR and further validated by in situ hybridization. Similarly, reduced protein expression was observed by immunohistochemistry and immunofluorescence in otosclerotic stapes that corroborate with immunoblotting of patients' plasma samples. Our findings identified that SERPINF1 variants are associated with the disease. Furthermore, reduced expression of SERPINF1 in otosclerotic stapes might contribute to OTSC pathophysiology.
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Affiliation(s)
- Neha Singh
- Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, India
- Regional Centre for Biotechnology, Faridabad, India
| | - Kirtal Hansdah
- Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, India
| | - Amal Bouzid
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Chinmay Sundar Ray
- Department of Ear, Nose, and Throat (ENT), Shrirama Chandra Bhanja (SCB) Medical College & Hospital, Cuttack, India
| | - Ashim Desai
- Dr. ABR Desai Ear, Nose and Throat (ENT) Clinic and Research Centre, Mumbai, India
| | - Khirod Chandra Panda
- Department of Ear, Nose, and Throat (ENT), Shrirama Chandra Bhanja (SCB) Medical College & Hospital, Cuttack, India
| | - Jyotish Chandra Choudhury
- Department of Forensic Medicine & Toxicology (FMT), Shrirama Chandra Bhanja (SCB) Medical College & Hospital, Cuttack, India
| | - Adel Tekari
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Puppala Venkat Ramchander
- Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, India.
- Regional Centre for Biotechnology, Faridabad, India.
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Donnan MD, Deb DK, David V, Quaggin SE. VEGF-C overexpression in kidney progenitor cells is a model of renal lymphangiectasia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.538868. [PMID: 37205366 PMCID: PMC10187188 DOI: 10.1101/2023.05.03.538868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Background Lymphangiogenesis is believed to be a protective response in the setting of multiple forms of kidney injury and mitigates the progression of interstitial fibrosis. To augment this protective response, promoting kidney lymphangiogenesis is being investigated as a potential treatment to slow the progression of kidney disease.As injury related lymphangiogenesis is driven by signaling from the receptor VEGFR-3 in response to the cognate growth factor VEGF-C released by tubular epithelial cells, this signaling pathway is a candidate for future kidney therapeutics. However, the consequences to kidney development and function to targeting this signaling pathway remains poorly defined. Methods We generated a new mouse model expressing Vegf-C under regulation of the nephron progenitor Six2Cre driver strain (Six2Vegf-C). Mice underwent a detailed phenotypic evaluation. Whole kidneys were processed for histology and micro computed tomography 3-dimensional imaging. Results Six2Vegf-C mice had reduced body weight and kidney function compared to littermate controls. Six2Vegf-C kidneys demonstrated large peripelvic fluid filled lesions with distortion of the pelvicalcyceal system which progressed in severity with age. 3D imaging showed a 3-fold increase in total cortical vascular density. Histology confirmed a substantial increase in LYVE1+/PDPN+/VEGFR3+ lymphatic capillaries extending alongside EMCN+ peritubular capillaries. There was no change in EMCN+ peritubular capillary density. Conclusions Kidney lymphangiogenesis was robustly induced in the Six2Vegf-C mice. There were no changes in peritubular blood capillary density despite these endothelial cells also expressing VEGFR-3. The model resulted in a severe cystic kidney phenotype that resembled a human condition termed renal lymphangiectasia. This study defines the vascular consequences of augmenting VEGF-C signaling during kidney development and provides new insight into a mimicker of human cystic kidney disease.
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Affiliation(s)
- Michael D Donnan
- Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Dilip K Deb
- Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Valentin David
- Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Susan E Quaggin
- Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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Panzaru MC, Florea A, Caba L, Gorduza EV. Classification of osteogenesis imperfecta: Importance for prophylaxis and genetic counseling. World J Clin Cases 2023; 11:2604-2620. [PMID: 37214584 PMCID: PMC10198117 DOI: 10.12998/wjcc.v11.i12.2604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/18/2023] [Accepted: 03/27/2023] [Indexed: 04/25/2023] Open
Abstract
Osteogenesis imperfecta (OI) is a genetically heterogeneous monogenic disease characterized by decreased bone mass, bone fragility, and recurrent fractures. The phenotypic spectrum varies considerably ranging from prenatal fractures with lethal outcomes to mild forms with few fractures and normal stature. The basic mechanism is a collagen-related defect, not only in synthesis but also in folding, processing, bone mineralization, or osteoblast function. In recent years, great progress has been made in identifying new genes and molecular mechanisms underlying OI. In this context, the classification of OI has been revised several times and different types are used. The Sillence classification, based on clinical and radiological characteristics, is currently used as a grading of clinical severity. Based on the metabolic pathway, the functional classification allows identifying regulatory elements and targeting specific therapeutic approaches. Genetic classification has the advantage of identifying the inheritance pattern, an essential element for genetic counseling and prophylaxis. Although genotype-phenotype correlations may sometimes be challenging, genetic diagnosis allows a personalized management strategy, accurate family planning, and pregnancy management decisions including options for mode of delivery, or early antenatal OI treatment. Future research on molecular pathways and pathogenic variants involved could lead to the development of genotype-based therapeutic approaches. This narrative review summarizes our current understanding of genes, molecular mechanisms involved in OI, classifications, and their utility in prophylaxis.
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Affiliation(s)
- Monica-Cristina Panzaru
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi 700115, Romania
| | - Andreea Florea
- Department of Medical Genetics - Medical Genetics resident, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi 700115, Romania
| | - Lavinia Caba
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi 700115, Romania
| | - Eusebiu Vlad Gorduza
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi 700115, Romania
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Alcorta-Sevillano N, Infante A, Macías I, Rodríguez CI. Murine Animal Models in Osteogenesis Imperfecta: The Quest for Improving the Quality of Life. Int J Mol Sci 2022; 24:ijms24010184. [PMID: 36613624 PMCID: PMC9820162 DOI: 10.3390/ijms24010184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/25/2022] Open
Abstract
Osteogenesis imperfecta is a rare genetic disorder characterized by bone fragility, due to alterations in the type I collagen molecule. It is a very heterogeneous disease, both genetically and phenotypically, with a high variability of clinical phenotypes, ranging from mild to severe forms, the most extreme cases being perinatal lethal. There is no curative treatment for OI, and so great efforts are being made in order to develop effective therapies. In these attempts, the in vivo preclinical studies are of paramount importance; therefore, serious analysis is required to choose the right murine OI model able to emulate as closely as possible the disease of the target OI population. In this review, we summarize the features of OI murine models that have been used for preclinical studies until today, together with recently developed new murine models. The bone parameters that are usually evaluated in order to determine the relevance of new developing therapies are exposed, and finally, current and innovative therapeutic strategies attempts considered in murine OI models, along with their mechanism of action, are reviewed. This review aims to summarize the in vivo studies developed in murine models available in the field of OI to date, in order to help the scientific community choose the most accurate OI murine model when developing new therapeutic strategies capable of improving the quality of life.
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Affiliation(s)
- Natividad Alcorta-Sevillano
- Stem Cells and Cell Therapy Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Plaza de Cruces S/N, 48903 Barakaldo, Spain
- Department of Cell Biology and Histology, University of Basque Country UPV/EHU, 48940 Leioa, Spain
| | - Arantza Infante
- Stem Cells and Cell Therapy Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Plaza de Cruces S/N, 48903 Barakaldo, Spain
| | - Iratxe Macías
- Stem Cells and Cell Therapy Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Plaza de Cruces S/N, 48903 Barakaldo, Spain
| | - Clara I. Rodríguez
- Stem Cells and Cell Therapy Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Plaza de Cruces S/N, 48903 Barakaldo, Spain
- Correspondence:
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Hedjazi G, Guterman-Ram G, Blouin S, Schemenz V, Wagermaier W, Fratzl P, Hartmann MA, Zwerina J, Fratzl-Zelman N, Marini JC. Alterations of bone material properties in growing Ifitm5/BRIL p.S42 knock-in mice, a new model for atypical type VI osteogenesis imperfecta. Bone 2022; 162:116451. [PMID: 35654352 PMCID: PMC11162744 DOI: 10.1016/j.bone.2022.116451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/17/2022] [Accepted: 05/25/2022] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Osteogenesis imperfecta (OI) is a heterogenous group of heritable connective tissue disorders characterized by high bone fragility due to low bone mass and impaired bone material properties. Atypical type VI OI is an extremely rare and severe form of bone dysplasia resulting from a loss-of-function mutation (p.S40L) in IFITM5/BRIL,the causative gene of OI type V and decreased osteoblast secretion of pigment epithelium-derived factor (PEDF), as in OI type VI. It is not yet known which alterations at the material level might lead to such a severe phenotype. We therefore characterized bone tissue at the micrometer level in a novel heterozygous Ifitm5/BRIL p.S42L knock-in murine model at 4 and 8 weeks of age. METHODS We evaluated in female mice, total body size, femoral and lumbar bone mineral density (BMD) by dual-energy X-ray absorptiometry. In the femoral bone we examined osteoid deposition by light microscopy, assessed bone histomorphometry and mineralization density distribution by quantitative backscattered electron imaging (qBEI). Osteocyte lacunae were examined by qBEI and the osteocyte lacuno-canalicular network by confocal laser scanning microscopy. Vasculature was examined indirectly by qBEI as 2D porosity in cortex, and as 3D porosity by micro-CT in third trochanter. Collagen orientation was examined by second harmonic generation microscopy. Two-way ANOVA was used to discriminate the effect of age and genotype. RESULTS Ifitm5/BRIL p.S42L female mice are viable, do not differ in body size, fat and lean mass from wild type (WT) littermates but have lower whole-body, lumbar and femoral BMD and multiple fractures. The average and most frequent calcium concentration, CaMean and CaPeak, increased with age in metaphyseal and cortical bone in both genotypes and were always higher in Ifitm5/BRIL p.S42L than in WT, except CaMean in metaphysis at 4 weeks of age. The fraction of highly mineralized bone area, CaHigh, was also increased in Ifitm5/BRIL p.S42L metaphyseal bone at 8 weeks of age and at both ages in cortical bone. The fraction of lowly mineralized bone area, CaLow, decreased with age and was not higher in Ifitm5/BRIL p.S42L, consistent with lack of hyperosteoidosis on histological sections by visual exam. Osteocyte lacunae density was higher in Ifitm5/BRIL p.S42L than WT, whereas canalicular density was decreased. Indirect measurements of vascularity revealed a higher pore density at 4 weeks in cortical bone of Ifitm5/BRIL p.S42L than in WT and at both ages in the third trochanter. Importantly, the proportion of bone area with disordered collagen fibrils was highly increased in Ifitm5/BRIL p.S42L at both ages. CONCLUSIONS Despite normal skeletal growth and the lack of a collagen gene mutation, the Ifitm5/BRIL p.S42L mouse shows major OI-related bone tissue alterations such as hypermineralization of the matrix and elevated osteocyte porosity. Together with the disordered lacuno-canalicular network and the disordered collagen fibril orientation, these abnormalities likely contribute to overall bone fragility.
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Affiliation(s)
- Ghazal Hedjazi
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - Gali Guterman-Ram
- Section on Heritable Disorders of Bone and Extracellular Matrix, NICHD, NIH, Bethesda, USA
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Heinrich Collin Strasse 30, 1140 Vienna, Austria; Vienna Bone and Growth Center, Vienna, Austria
| | - Victoria Schemenz
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Wolfgang Wagermaier
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Heinrich Collin Strasse 30, 1140 Vienna, Austria; Vienna Bone and Growth Center, Vienna, Austria
| | - Jochen Zwerina
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Heinrich Collin Strasse 30, 1140 Vienna, Austria; Vienna Bone and Growth Center, Vienna, Austria
| | - Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Heinrich Collin Strasse 30, 1140 Vienna, Austria; Vienna Bone and Growth Center, Vienna, Austria
| | - Joan C Marini
- Section on Heritable Disorders of Bone and Extracellular Matrix, NICHD, NIH, Bethesda, USA.
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