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Costa A, Martins A, Machado C, Lundberg E, Nilsson O, Wang F, Costantini A, Tournis S, Höppner J, Grasemann C, Mäkitie O. PLS3 Mutations in X-Linked Osteoporosis: Clinical and Genetic Features in Five New Families. Calcif Tissue Int 2024; 114:157-170. [PMID: 38043102 PMCID: PMC10803541 DOI: 10.1007/s00223-023-01162-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/06/2023] [Indexed: 12/05/2023]
Abstract
Childhood-onset osteoporosis is a rare but clinically significant condition. Studies have shown pathogenic variants in more than 20 different genes as causative for childhood-onset primary osteoporosis. The X-chromosomal PLS3, encoding Plastin-3, is one of the more recently identified genes. In this study, we describe five new families from four different European countries with PLS3-related skeletal fragility. The index cases were all hemizygous males presenting with long bone and vertebral body compression fractures. All patients had low lumbar spine bone mineral density (BMD). The age at the first clinical fracture ranged from 1.5 to 13 years old. Three of the identified PLS3 variants were stop-gain variants and two were deletions involving either a part or all exons of the gene. In four families the variant was inherited from the mother. All heterozygous women reported here had normal BMD and no bone fractures. Four patients received bisphosphonate treatment with good results, showing a lumbar spine BMD increment and vertebral body reshaping after 10 months to 2 years of treatment. Our findings expand the genetic spectrum of PLS3-related osteoporosis. Our report also shows that early treatment with bisphosphonates may influence the disease course and reduce the progression of osteoporosis, highlighting the importance of early diagnosis for prompt intervention and appropriate genetic counseling.
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Affiliation(s)
- Adriana Costa
- Department of Pediatrics, Hospital Prof. Doutor Fernando Fonseca EPE, Amadora, Portugal.
| | - Andreia Martins
- Department of Pediatrics, Hospital Prof. Doutor Fernando Fonseca EPE, Amadora, Portugal
| | - Catarina Machado
- Department of Pediatrics, Hospital Prof. Doutor Fernando Fonseca EPE, Amadora, Portugal
| | - Elena Lundberg
- Department of Pediatrics, Institution of Clinical Science, Umea University, Umeå, Sweden
| | - Ola Nilsson
- Division of Pediatric Endocrinology and Center for Molecular Medicine, Department of Women's and Children's Health, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
- Department of Medical Sciences, Örebro University and University Hospital, Örebro, Sweden
| | - Fan Wang
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, and Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Alice Costantini
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, and Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Symeon Tournis
- Laboratory for Research of the Musculoskeletal System "Th. Garofalidis", Medical School, University of Athens, Athens, Greece
| | - Jakob Höppner
- Department of Pediatrics, St. Josef-Hospital Bochum, Ruhr-University Bochum, Bochum, Germany
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Corinna Grasemann
- Department of Pediatrics, St. Josef-Hospital Bochum, Ruhr-University Bochum, Bochum, Germany
| | - Outi Mäkitie
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, and Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children's Hospital and Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Folkhälsan Research Center, Helsinki, Finland
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2
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Ward LM. A practical guide to the diagnosis and management of osteoporosis in childhood and adolescence. Front Endocrinol (Lausanne) 2024; 14:1266986. [PMID: 38374961 PMCID: PMC10875302 DOI: 10.3389/fendo.2023.1266986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/18/2023] [Indexed: 02/21/2024] Open
Abstract
Osteoporosis in childhood distinguishes itself from adulthood in four important ways: 1) challenges in distinguishing otherwise healthy children who have experienced fractures due to non-accidental injury or misfortunate during sports and play from those with an underlying bone fragility condition; 2) a preponderance of monogenic "early onset" osteoporotic conditions that unveil themselves during the pediatric years; 3) the unique potential, in those with residual growth and transient bone health threats, to reclaim bone density, structure, and strength without bone-targeted therapy; and 4) the need to benchmark bone health metrics to constantly evolving "normal targets", given the changes in bone size, shape, and metabolism that take place from birth through late adolescence. On this background, the pediatric osteoporosis field has evolved considerably over the last few decades, giving rise to a deeper understanding of the discrete genes implicated in childhood-onset osteoporosis, the natural history of bone fragility in the chronic illness setting and associated risk factors, effective diagnostic and monitoring pathways in different disease contexts, the importance of timely identification of candidates for osteoporosis treatment, and the benefits of early (during growth) rather than late (post-epiphyseal fusion) treatment. While there has been considerable progress, a number of unmet needs remain, the most urgent of which is to move beyond the monotherapeutic anti-resorptive landscape to the study and application of anabolic agents that are anticipated to not only improve bone mineral density but also increase long bone cross-sectional diameter (periosteal circumference). The purpose of this review is to provide a practical guide to the diagnosis and management of osteoporosis in children presenting to the clinic with fragility fractures, one that serves as a step-by-step "how to" reference for clinicians in their routine clinical journey. The article also provides a sightline to the future, emphasizing the clinical scenarios with the most urgent need for an expanded toolbox of effective osteoporosis agents in childhood.
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Affiliation(s)
- Leanne M. Ward
- Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
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3
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Pihlström S, Richardt S, Määttä K, Pekkinen M, Olkkonen VM, Mäkitie O, Mäkitie RE. SGMS2 in primary osteoporosis with facial nerve palsy. Front Endocrinol (Lausanne) 2023; 14:1224318. [PMID: 37886644 PMCID: PMC10598846 DOI: 10.3389/fendo.2023.1224318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/18/2023] [Indexed: 10/28/2023] Open
Abstract
Pathogenic heterozygous variants in SGMS2 cause a rare monogenic form of osteoporosis known as calvarial doughnut lesions with bone fragility (CDL). The clinical presentations of SGMS2-related bone pathology range from childhood-onset osteoporosis with low bone mineral density and sclerotic doughnut-shaped lesions in the skull to a severe spondylometaphyseal dysplasia with neonatal fractures, long-bone deformities, and short stature. In addition, neurological manifestations occur in some patients. SGMS2 encodes sphingomyelin synthase 2 (SMS2), an enzyme involved in the production of sphingomyelin (SM). This review describes the biochemical structure of SM, SM metabolism, and their molecular actions in skeletal and neural tissue. We postulate how disrupted SM gradient can influence bone formation and how animal models may facilitate a better understanding of SGMS2-related osteoporosis.
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Affiliation(s)
- Sandra Pihlström
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sampo Richardt
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kirsi Määttä
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Minna Pekkinen
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children´s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children´s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Riikka E. Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology – Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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4
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Costantini A, Mäkitie RE, Hartmann MA, Fratzl-Zelman N, Zillikens MC, Kornak U, Søe K, Mäkitie O. Early-Onset Osteoporosis: Rare Monogenic Forms Elucidate the Complexity of Disease Pathogenesis Beyond Type I Collagen. J Bone Miner Res 2022; 37:1623-1641. [PMID: 35949115 PMCID: PMC9542053 DOI: 10.1002/jbmr.4668] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 07/22/2022] [Accepted: 08/01/2022] [Indexed: 12/05/2022]
Abstract
Early-onset osteoporosis (EOOP), characterized by low bone mineral density (BMD) and fractures, affects children, premenopausal women and men aged <50 years. EOOP may be secondary to a chronic illness, long-term medication, nutritional deficiencies, etc. If no such cause is identified, EOOP is regarded primary and may then be related to rare variants in genes playing a pivotal role in bone homeostasis. If the cause remains unknown, EOOP is considered idiopathic. The scope of this review is to guide through clinical and genetic diagnostics of EOOP, summarize the present knowledge on rare monogenic forms of EOOP, and describe how analysis of bone biopsy samples can lead to a better understanding of the disease pathogenesis. The diagnostic pathway of EOOP is often complicated and extensive assessments may be needed to reliably exclude secondary causes. Due to the genetic heterogeneity and overlapping features in the various genetic forms of EOOP and other bone fragility disorders, the genetic diagnosis usually requires the use of next-generation sequencing to investigate several genes simultaneously. Recent discoveries have elucidated the complexity of disease pathogenesis both regarding genetic architecture and bone tissue-level pathology. Two rare monogenic forms of EOOP are due to defects in genes partaking in the canonical WNT pathway: LRP5 and WNT1. Variants in the genes encoding plastin-3 (PLS3) and sphingomyelin synthase 2 (SGMS2) have also been found in children and young adults with skeletal fragility. The molecular mechanisms leading from gene defects to clinical manifestations are often not fully understood. Detailed analysis of patient-derived transiliac bone biopsies gives valuable information to understand disease pathogenesis, distinguishes EOOP from other bone fragility disorders, and guides in patient management, but is not widely available in clinical settings. Despite the great advances in this field, EOOP remains an insufficiently explored entity and further research is needed to optimize diagnostic and therapeutic approaches. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Alice Costantini
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Paris Cité University, INSERM UMR1163, Institut Imagine, Paris, France
| | - Riikka E Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department 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 Medical Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - M Carola Zillikens
- Bone Center, Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Uwe Kornak
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Kent Søe
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, Odense, Denmark.,Clinical Cell Biology, Pathology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Outi Mäkitie
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Folkhälsan Institute of Genetics, Helsinki, Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Children's Hospital and Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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5
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Mäkitie RE, Henning P, Jiu Y, Kämpe A, Kogan K, Costantini A, Välimäki V, Medina‐Gomez C, Pekkinen M, Salusky IB, Schalin‐Jäntti C, Haanpää MK, Rivadeneira F, Bassett JHD, Williams GR, Lerner UH, Pereira RC, Lappalainen P, Mäkitie O. An ARHGAP25 variant links aberrant Rac1 function to early-onset skeletal fragility. JBMR Plus 2021; 5:e10509. [PMID: 34258505 PMCID: PMC8260816 DOI: 10.1002/jbm4.10509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/10/2021] [Accepted: 04/21/2021] [Indexed: 11/10/2022] Open
Abstract
Ras homologous guanosine triphosphatases (RhoGTPases) control several cellular functions, including cytoskeletal actin remodeling and cell migration. Their activities are downregulated by GTPase-activating proteins (GAPs). Although RhoGTPases are implicated in bone remodeling and osteoclast and osteoblast function, their significance in human bone health and disease remains elusive. Here, we report defective RhoGTPase regulation as a cause of severe, early-onset, autosomal-dominant skeletal fragility in a three-generation Finnish family. Affected individuals (n = 13) presented with multiple low-energy peripheral and vertebral fractures despite normal bone mineral density (BMD). Bone histomorphometry suggested reduced bone volume, low surface area covered by osteoblasts and osteoclasts, and low bone turnover. Exome sequencing identified a novel heterozygous missense variant c.652G>A (p.G218R) in ARHGAP25, encoding a GAP for Rho-family GTPase Rac1. Variants in the ARHGAP25 5' untranslated region (UTR) also associated with BMD and fracture risk in the general population, across multiple genomewide association study (GWAS) meta-analyses (lead variant rs10048745). ARHGAP25 messenger RNA (mRNA) was expressed in macrophage colony-stimulating factor (M-CSF)-stimulated human monocytes and mouse osteoblasts, indicating a possible role for ARHGAP25 in osteoclast and osteoblast differentiation and activity. Studies on subject-derived osteoclasts from peripheral blood mononuclear cells did not reveal robust defects in mature osteoclast formation or resorptive activity. However, analysis of osteosarcoma cells overexpressing the ARHGAP25 G218R-mutant, combined with structural modeling, confirmed that the mutant protein had decreased GAP-activity against Rac1, resulting in elevated Rac1 activity, increased cell spreading, and membrane ruffling. Our findings indicate that mutated ARHGAP25 causes aberrant Rac1 function and consequently abnormal bone metabolism, highlighting the importance of RhoGAP signaling in bone metabolism in familial forms of skeletal fragility and in the general population, and expanding our understanding of the molecular pathways underlying skeletal fragility. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Riikka E. Mäkitie
- Folkhälsan Institute of GeneticsHelsinkiFinland
- Research Program for Clinical and Molecular Metabolism, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and ReproductionImperial College LondonLondonUK
| | - Petra Henning
- Department of Internal Medicine and Clinical NutritionCentre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of GothenburgGothenburgSweden
| | - Yaming Jiu
- HiLIFE Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of ShanghaiChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Anders Kämpe
- Department of Molecular Medicine and Surgery and Center for Molecular MedicineKarolinska InstitutetStockholmSweden
| | - Konstantin Kogan
- HiLIFE Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
| | - Alice Costantini
- Department of Molecular Medicine and Surgery and Center for Molecular MedicineKarolinska InstitutetStockholmSweden
| | - Ville‐Valtteri Välimäki
- Department of Orthopaedics and TraumatologyHelsinki University Central Hospital and Helsinki University, Jorvi HospitalEspooFinland
| | - Carolina Medina‐Gomez
- Department of Internal MedicineErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Minna Pekkinen
- Folkhälsan Institute of GeneticsHelsinkiFinland
- Research Program for Clinical and Molecular Metabolism, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland
| | - Isidro B. Salusky
- Department of PediatricsDavid Geffen School of Medicine at UCLALos AngelesCaliforniaUSA
| | - Camilla Schalin‐Jäntti
- Endocrinology, Abdominal CenterUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | - Maria K. Haanpää
- Department of Genomics and Clinical GeneticsTurku University HospitalTurkuFinland
| | - Fernando Rivadeneira
- Department of Internal MedicineErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - John H. Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and ReproductionImperial College LondonLondonUK
| | - Graham R. Williams
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and ReproductionImperial College LondonLondonUK
| | - Ulf H. Lerner
- Department of Internal Medicine and Clinical NutritionCentre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of GothenburgGothenburgSweden
| | - Renata C. Pereira
- Department of PediatricsDavid Geffen School of Medicine at UCLALos AngelesCaliforniaUSA
| | - Pekka Lappalainen
- HiLIFE Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
| | - Outi Mäkitie
- Folkhälsan Institute of GeneticsHelsinkiFinland
- Research Program for Clinical and Molecular Metabolism, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland
- Department of Molecular Medicine and Surgery and Center for Molecular MedicineKarolinska InstitutetStockholmSweden
- Children's HospitalUniversity and Helsinki University HospitalHelsinkiFinland
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6
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Plastin 3 in health and disease: a matter of balance. Cell Mol Life Sci 2021; 78:5275-5301. [PMID: 34023917 PMCID: PMC8257523 DOI: 10.1007/s00018-021-03843-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 02/06/2023]
Abstract
For a long time, PLS3 (plastin 3, also known as T-plastin or fimbrin) has been considered a rather inconspicuous protein, involved in F-actin-binding and -bundling. However, in recent years, a plethora of discoveries have turned PLS3 into a highly interesting protein involved in many cellular processes, signaling pathways, and diseases. PLS3 is localized on the X-chromosome, but shows sex-specific, inter-individual and tissue-specific expression variability pointing towards skewed X-inactivation. PLS3 is expressed in all solid tissues but usually not in hematopoietic cells. When escaping X-inactivation, PLS3 triggers a plethora of different types of cancers. Elevated PLS3 levels are considered a prognostic biomarker for cancer and refractory response to therapies. When it is knocked out or mutated in humans and mice, it causes osteoporosis with bone fractures; it is the only protein involved in actin dynamics responsible for osteoporosis. Instead, when PLS3 is upregulated, it acts as a highly protective SMN-independent modifier in spinal muscular atrophy (SMA). Here, it seems to counteract reduced F-actin levels by restoring impaired endocytosis and disturbed calcium homeostasis caused by reduced SMN levels. In contrast, an upregulation of PLS3 on wild-type level might cause osteoarthritis. This emphasizes that the amount of PLS3 in our cells must be precisely balanced; both too much and too little can be detrimental. Actin-dynamics, regulated by PLS3 among others, are crucial in a lot of cellular processes including endocytosis, cell migration, axonal growth, neurotransmission, translation, and others. Also, PLS3 levels influence the infection with different bacteria, mycosis, and other pathogens.
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7
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El-Gazzar A, Högler W. Mechanisms of Bone Fragility: From Osteogenesis Imperfecta to Secondary Osteoporosis. Int J Mol Sci 2021; 22:ijms22020625. [PMID: 33435159 PMCID: PMC7826666 DOI: 10.3390/ijms22020625] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 12/13/2022] Open
Abstract
Bone material strength is determined by several factors, such as bone mass, matrix composition, mineralization, architecture and shape. From a clinical perspective, bone fragility is classified as primary (i.e., genetic and rare) or secondary (i.e., acquired and common) osteoporosis. Understanding the mechanism of rare genetic bone fragility disorders not only advances medical knowledge on rare diseases, it may open doors for drug development for more common disorders (i.e., postmenopausal osteoporosis). In this review, we highlight the main disease mechanisms underlying the development of human bone fragility associated with low bone mass known to date. The pathways we focus on are type I collagen processing, WNT-signaling, TGF-ß signaling, the RANKL-RANK system and the osteocyte mechanosensing pathway. We demonstrate how the discovery of most of these pathways has led to targeted, pathway-specific treatments.
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Affiliation(s)
| | - Wolfgang Högler
- Correspondence: ; Tel.: +43-(0)5-7680-84-22001; Fax: +43-(0)5-7680-84-22004
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8
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Zhang B, Li R, Wang W, Zhou X, Luo B, Zhu Z, Zhang X, Ding A. The role of WNT1 mutant variant (WNT1 c.677C>T ) in osteogenesis imperfecta. Ann Hum Genet 2020; 84:447-455. [PMID: 32757296 PMCID: PMC7590185 DOI: 10.1111/ahg.12399] [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: 10/31/2019] [Revised: 06/27/2020] [Accepted: 07/01/2020] [Indexed: 12/13/2022]
Abstract
Osteogenesis imperfecta (OI), also known as "brittle bone disease," is a rare inherited genetic disorder characterized by bone fragility and often associated with short stature. The mutation in WNT1 causes autosomal recessive OI (AR-OI) due to the key role of WNT/β-catenin signaling in bone formation. WNT1 mutations cause phenotypes in OI of varying degrees of clinical severity, ranging from moderate to progressively deforming forms. The nucleotide change c.677C > T is one of the recurrent variants in the WNT1 alleles in Chinese AR-OI patients. To explore the effects of mutation c.677C > T on WNT1 function, we evaluated the activation of WNT/β-catenin signaling, cell proliferation, osteoblast differentiation, and osteoclast differentiation in WNT1c.677C>T , WNT1c.884C>A , and wild type WNT1 transfected into MC3T3-E1 preosteoblasts. Plasmids containing wild type WNT1, WNT1c.677C>T , and WNT1c.884C>A cDNAs were constructed. Protein levels of phosphorylation at serine 9 of GSK-3β (p-GSK-3β), GSK-3β, nonphosphorylated β-catenin (non-p-β-catenin), and β-catenin were detected with western blot. Cell proliferation was determined using MTS. BMP-2 and RANKL mRNA and protein levels were detected by qPCR and western blot. Our results showed that WNT1c.677C>T failed to activate WNT/β-catenin signaling and impaired the proliferation of preosteoblasts. Moreover, compared to wild type WNT1, WNT1c.677C>T downregulated BMP-2 protein expression and was exhibited a diminished capacity to suppress the RANKL protein level. In conclusion, mutation c.677C > T hindered the ability of WNT1 to induce the WNT/β-catenin signaling pathway and it affected the WNT/β-catenin pathway which might potentially contribute to hampered bone homeostasis.
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Affiliation(s)
- Bashan Zhang
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Rong Li
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Wenfeng Wang
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Xueming Zhou
- Department of Orthopedic, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Beijing Luo
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Zinian Zhu
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Xibo Zhang
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
| | - Aijiao Ding
- Clinical Laboratory, Affiliated Dongguan People's Hospital, Southern Medical University, Dongguan, China
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9
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Postmenopausal Osteoporosis reference genes for qPCR expression assays. Sci Rep 2019; 9:16533. [PMID: 31712560 PMCID: PMC6848520 DOI: 10.1038/s41598-019-52612-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 10/14/2019] [Indexed: 02/05/2023] Open
Abstract
Osteoporosis (OP) is a multifactorial disease influenced by genetic factors in more than half of the cases. In spite of the efforts to clarify the relationship among genetic factors and susceptibility to develop OP, many genetic associations need to be further functionally validated. Besides, some limitations as the choice of stably expressed reference genes (RG) should be overcome to ensure the quality and reproducibility of gene expression assays. To our knowledge, a validation study for RG in OP is still missing. We compared the expression levels, using polymerase chain reaction quantitative real time (qPCR) of 10 RG (G6PD, B2M, GUSB, HSP90, EF1A, RPLP0, GAPDH, ACTB, 18 S and HPRT1) to assess their suitability in OP analysis by using GeNorm, Normfinder, BestKeeper and RefFinder programs. A minimal number of two RG was recommended by GeNorm to obtain a reliable normalization. RPLP0 and B2M were identified as the most stable genes in OP studies while ACTB, 18 S and HPRT1 were inadequate for normalization in our data set. Moreover, we showed the dramatic effects of suboptimal RG choice on the quantification of a target gene, highlighting the importance in the identification of the most appropriate reference gene to specific diseases. We suggest the use of RPLP0 and B2M as the most stable reference genes while we do not recommend the use of the least stable reference genes HPRT1, 18 S and ACTB in OP expression assays using PBMC as biological source. Additionally, we emphasize the importance of individualized and careful choice in software and reference genes selection.
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10
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Besio R, Chow CW, Tonelli F, Marini JC, Forlino A. Bone biology: insights from osteogenesis imperfecta and related rare fragility syndromes. FEBS J 2019; 286:3033-3056. [PMID: 31220415 PMCID: PMC7384889 DOI: 10.1111/febs.14963] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/06/2019] [Accepted: 06/14/2019] [Indexed: 12/11/2022]
Abstract
The limited accessibility of bone and its mineralized nature have restricted deep investigation of its biology. Recent breakthroughs in identification of mutant proteins affecting bone tissue homeostasis in rare skeletal diseases have revealed novel pathways involved in skeletal development and maintenance. The characterization of new dominant, recessive and X-linked forms of the rare brittle bone disease osteogenesis imperfecta (OI) and other OI-related bone fragility disorders was a key player in this advance. The development of in vitro models for these diseases along with the generation and characterization of murine and zebrafish models contributed to dissecting previously unknown pathways. Here, we describe the most recent advances in the understanding of processes involved in abnormal bone mineralization, collagen processing and osteoblast function, as illustrated by the characterization of new causative genes for OI and OI-related fragility syndromes. The coordinated role of the integral membrane protein BRIL and of the secreted protein PEDF in modulating bone mineralization as well as the function and cross-talk of the collagen-specific chaperones HSP47 and FKBP65 in collagen processing and secretion are discussed. We address the significance of WNT ligand, the importance of maintaining endoplasmic reticulum membrane potential and of regulating intramembrane proteolysis in osteoblast homeostasis. Moreover, we also examine the relevance of the cytoskeletal protein plastin-3 and of the nucleotidyltransferase FAM46A. Thanks to these advances, new targets for the development of novel therapies for currently incurable rare bone diseases have been and, likely, will be identified, supporting the important role of basic science for translational approaches.
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Affiliation(s)
- Roberta Besio
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Chi-Wing Chow
- Bone and Extracellular Matrix Branch, NICHD, National Institute of Health, Bethesda, MD 20892, USA
| | - Francesca Tonelli
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Joan C Marini
- Bone and Extracellular Matrix Branch, NICHD, National Institute of Health, Bethesda, MD 20892, USA
| | - Antonella Forlino
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
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11
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Khassan O, Jensen KV, Woodman AG, Vogel HJ, Ishida H. Characterization of the EF-Hand Calcium-Binding Domains of Human Plastins. Methods Mol Biol 2019; 1929:245-260. [PMID: 30710278 DOI: 10.1007/978-1-4939-9030-6_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The three human plastins (L-plastin, T-plastin, and I-plastin) are important regulatory Ca2+-binding proteins that belong to the family of actin-binding proteins. Plastins are involved in the regulation of the actin cytoskeleton as well as the cross-linking of actin filaments. In addition to four calponin-homology (CH) domains, all three plastins contain two N-terminal EF-hand Ca2+-binding motifs which together are homologous to a single lobe of the well-known calcium-regulatory protein calmodulin. This part of the protein allows for the regulation of the actin bundling activity in response to elevated calcium levels. In this protocol, we describe the purification of the EF-hand headpiece domains of all three plastins, as well as SPR studies, ITC studies, and NMR interaction studies with different peptides and calcium. In combination, these three experimental techniques provide detailed insights into a novel regulatory mechanism, involving the linker region between the EF-hand domain and the first CH domain of the plastins.
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Affiliation(s)
- Oleg Khassan
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Katharine V Jensen
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Andrew G Woodman
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.
| | - Hiroaki Ishida
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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12
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Fiscaletti M, Coorey CP, Biggin A, Briody J, Little DG, Schindeler A, Munns CF. Diagnosis of Recurrent Fracture in a Pediatric Cohort. Calcif Tissue Int 2018; 103:529-539. [PMID: 29943187 DOI: 10.1007/s00223-018-0449-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/20/2018] [Indexed: 01/08/2023]
Abstract
Significant fracture history in children is defined as having at least one vertebral fracture, at least 2 fractures by age 10, or at least 3 fractures by age 19. Between September 2011 and December 2014, clinical data were collected on children with a significant fracture history that attended a major Australian children's hospital. Fifty-six patients were identified as having 305 fractures in total, including 44 vertebral fractures. 18% of patients (10/56) were diagnosed with osteogenesis imperfecta (OI) by a bone health expert, molecular testing or both, and they sustained 23% of all fractures (71/305). Analysis of serum bone biochemistry showed all median values to be within a normal range and no clinically significant differences between patients with and without OI. The DXA and pQCT derived bone mineral density (BMD) and bone mineral content (BMC) Z scores were reduced overall. DXA derived total body and lumbar spine areal BMD-for-age and BMC-for-age Z scores were significantly lower in children who had vertebral fractures or who were later diagnosed with OI. Similarly, pQCT performed on radii and tibiae showed Z scores significantly less than zero. pQCT-derived limb muscle cross sectional area Z scores were significantly lower in the OI subgroup. In conclusion, this study describes the bone phenotype of children referred to a tertiary hospital clinic for recurrent fractures and highlights a subset of children with previously undiagnosed OI, but a larger cohort without classic OI. Thus it can be clinically challenging to differentiate between children with OI type 1 (mild phenotype) and non-OI children without bone densitometry and genetic testing. We conclude that recurrent fractures in children should prompt a comprehensive bone and systemic health assessment to eliminate an underlying pathology.
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Affiliation(s)
- M Fiscaletti
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Westmead, NSW, Australia.
- Department of Endocrinology & Diabetes, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.
| | - C P Coorey
- Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - A Biggin
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - J Briody
- Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - D G Little
- Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Department of Orthopaedics, The Children's Hospital at Westmead, Sydney, NSW, Australia
- Orthopaedic Research & Biotechnology Unit, The Children's Hospital at Westmead, Westmead, Australia
| | - A Schindeler
- Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Orthopaedic Research & Biotechnology Unit, The Children's Hospital at Westmead, Westmead, Australia
| | - C F Munns
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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13
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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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14
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Costantini A, Krallis PΝ, Kämpe A, Karavitakis EM, Taylan F, Mäkitie O, Doulgeraki A. A novel frameshift deletion in PLS3 causing severe primary osteoporosis. J Hum Genet 2018; 63:923-926. [PMID: 29884797 DOI: 10.1038/s10038-018-0472-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/19/2018] [Accepted: 05/08/2018] [Indexed: 12/11/2022]
Abstract
Mutations in the gene encoding plastin-3, PLS3, have recently been associated to severe primary osteoporosis. The molecular function of plastin-3 is not fully understood. Since PLS3 is located on the X chromosome, males are usually more severely affected than females. PLS3 mutations have thus far been reported in approximately 20 young patients with low bone mineral density (BMD). We describe an 8-year-old Greek boy with severe primary osteoporosis with multiple vertebral compression fractures and one low-energy long bone fracture. His clinical manifestations were consistent with osteogenesis imperfecta, including blue sclerae, joint hypermobility, low bone mineral density, kyphosis, bilateral conductive hearing loss, and mild dysmorphic features. The family history was negative for primary osteoporosis. COL1A1 and COL1A2 mutations were excluded by Sanger sequencing. However, Sanger sequencing of PLS3 led to the identification of a de novo frameshift deletion, NM_005032: c.1096_1100delAACTT, p.(Asn366Serfs*5), in exon 10 confirming the diagnosis of PLS3 osteoporosis. In conclusion, we describe a novel frameshift deletion in PLS3 causing severe primary osteoporosis in a boy. Our finding highlights the clinical overlap between type I collagen and PLS3-related skeletal fragility and underscores the importance of PLS3 screening in patients with multiple fractures to enable proper genetic counseling.
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Affiliation(s)
- Alice Costantini
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
| | | | - Anders Kämpe
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Fulya Taylan
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Outi Mäkitie
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Folkhälsan Institute of Genetics and University of Helsinki, Helsinki, Finland.,Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Artemis Doulgeraki
- Department of Bone and Mineral Metabolism, Institute of Child Health, "Aghia Sophia" Children's Hospital, Athens, Greece
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15
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Orriss IR, Lanham S, Savery D, Greene NDE, Stanier P, Oreffo R, Copp AJ, Galea GL. Spina bifida-predisposing heterozygous mutations in Planar Cell Polarity genes and Zic2 reduce bone mass in young mice. Sci Rep 2018; 8:3325. [PMID: 29463853 PMCID: PMC5820290 DOI: 10.1038/s41598-018-21718-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 02/07/2018] [Indexed: 12/21/2022] Open
Abstract
Fractures are a common comorbidity in children with the neural tube defect (NTD) spina bifida. Mutations in the Wnt/planar cell polarity (PCP) pathway contribute to NTDs in humans and mice, but whether this pathway independently determines bone mass is poorly understood. Here, we first confirmed that core Wnt/PCP components are expressed in osteoblasts and osteoclasts in vitro. In vivo, we performed detailed µCT comparisons of bone structure in tibiae from young male mice heterozygous for NTD-associated mutations versus WT littermates. PCP signalling disruption caused by Vangl2 (Vangl2Lp/+) or Celsr1 (Celsr1Crsh/+) mutations significantly reduced trabecular bone mass and distal tibial cortical thickness. NTD-associated mutations in non-PCP transcription factors were also investigated. Pax3 mutation (Pax3Sp2H/+) had minimal effects on bone mass. Zic2 mutation (Zic2Ku/+) significantly altered the position of the tibia/fibula junction and diminished cortical bone in the proximal tibia. Beyond these genes, we bioinformatically documented the known extent of shared genetic networks between NTDs and bone properties. 46 genes involved in neural tube closure are annotated with bone-related ontologies. These findings document shared genetic networks between spina bifida risk and bone structure, including PCP components and Zic2. Genetic variants which predispose to spina bifida may therefore independently diminish bone mass.
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Affiliation(s)
- Isabel R Orriss
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Camden, London, NW1 0TU, UK
| | - Stuart Lanham
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development and Health, Institute of Developmental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Dawn Savery
- Developmental Biology of Birth Defects, UCL GOS Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Nicholas D E Greene
- Developmental Biology of Birth Defects, UCL GOS Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Philip Stanier
- Developmental Biology of Birth Defects, UCL GOS Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Richard Oreffo
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development and Health, Institute of Developmental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Andrew J Copp
- Developmental Biology of Birth Defects, UCL GOS Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Gabriel L Galea
- Developmental Biology of Birth Defects, UCL GOS Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
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