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Tüysüz B, Usluer E, Uludağ Alkaya D, Ocak S, Saygılı S, Şeker A, Apak H. The molecular spectrum of Turkish osteopetrosis and related osteoclast disorders with natural history, including a candidate gene, CCDC120. Bone 2023; 177:116897. [PMID: 37704070 DOI: 10.1016/j.bone.2023.116897] [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: 06/12/2023] [Revised: 08/21/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023]
Abstract
BACKGROUND Osteopetrosis and related osteoclastic disorders are a heterogeneous group of inherited diseases characterized by increased bone density. The aim of this study is to investigate the molecular spectrum and natural history of the clinical and radiological features of these disorders. METHODS 28 patients from 20 families were enrolled in the study; 20 of them were followed for a period of 1-16 years. Targeted gene analysis and whole-exome sequencing (WES) were performed. RESULTS Biallelic mutations in CLCN7 and TCIRG1 were detected in three families each, in TNFRSF11A and CA2 in two families each, and in SNX10 in one family in the osteopetrosis group. A heterozygous variant in CLCN7 was also found in one family. In the osteopetrosis and related osteoclast disorders group, three different variants in CTSK were detected in five families with pycnodysostosis and a SLC29A3 variant causing dysosteosclerosis was detected in one family. In autosomal recessive osteopetrosis (ARO), a malignant infantile form, four patients died during follow-up, two of whom had undergone hematopoietic stem cell transplantation. Interestingly, all patients had osteopetrorickets of the long bone metaphyses in infancy, typical skeletal features such as Erlenmeyer flask deformity and bone-in-bone appearance that developed toward the end of early childhood. Two siblings with a biallelic missense mutation in CLCN7 and one patient with the compound heterozygous novel splicing variants in intron 15 and 17 in TCIRG1 corresponded to the intermediate form of ARO (IARO); there was intrafamilial clinical heterogeneity in the family with the CLCN7 variant. One of two patients with IARO and distal tubular acidosis was found to have a large deletion in CA2. In one family, two siblings with a heterozygous mutation in CLCN7 were affected, whereas the father with the same mutation was asymptomatic. In WES analysis of three brothers from a family without mutations in osteopetrosis genes, a hemizygous missense variant in CCDC120, a novel gene, was found to be associated with high bone mass. CONCLUSION This study extended the natural history of the different types of osteopetrosis and also introduced a candidate gene, CCDC120, potentially causing osteopetrosis.
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Affiliation(s)
- Beyhan Tüysüz
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Genetics, Istanbul, Turkey.
| | - Esra Usluer
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Genetics, Istanbul, Turkey
| | - Dilek Uludağ Alkaya
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Genetics, Istanbul, Turkey
| | - Süheyla Ocak
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Hematology, Istanbul, Turkey
| | - Seha Saygılı
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Nephrology, Istanbul, Turkey
| | - Ali Şeker
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Orthopedics and Traumatology, Istanbul, Turkey
| | - Hilmi Apak
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Hematology, Istanbul, Turkey
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Wang J, McVicar A, Chen Y, Deng HW, Zhao Z, Chen W, Li YP. Atp6i deficient mouse model uncovers transforming growth factor-β1 /Smad2/3 as a key signaling pathway regulating odontoblast differentiation and tooth root formation. Int J Oral Sci 2023; 15:35. [PMID: 37599332 PMCID: PMC10440342 DOI: 10.1038/s41368-023-00235-2] [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] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 06/01/2023] [Accepted: 07/03/2023] [Indexed: 08/22/2023] Open
Abstract
The biomolecular mechanisms that regulate tooth root development and odontoblast differentiation are poorly understood. We found that Atp6i deficient mice (Atp6i-/-) arrested tooth root formation, indicated by truncated Hertwig's epithelial root sheath (HERS) progression. Furthermore, Atp6i deficiency significantly reduced the proliferation and differentiation of radicular odontogenic cells responsible for root formation. Atp6i-/- mice had largely decreased expression of odontoblast differentiation marker gene expression profiles (Col1a1, Nfic, Dspp, and Osx) in the alveolar bone. Atp6i-/- mice sample RNA-seq analysis results showed decreased expression levels of odontoblast markers. Additionally, there was a significant reduction in Smad2/3 activation, inhibiting transforming growth factor-β (TGF-β) signaling in Atp6i-/- odontoblasts. Through treating pulp precursor cells with Atp6i-/- or wild-type OC bone resorption-conditioned medium, we found the latter medium to promote odontoblast differentiation, as shown by increased odontoblast differentiation marker genes expression (Nfic, Dspp, Osx, and Runx2). This increased expression was significantly blocked by anti-TGF-β1 antibody neutralization, whereas odontoblast differentiation and Smad2/3 activation were significantly attenuated by Atp6i-/- OC conditioned medium. Importantly, ectopic TGF-β1 partially rescued root development and root dentin deposition of Atp6i-/- mice tooth germs were transplanted under mouse kidney capsules. Collectively, our novel data shows that the prevention of TGF-β1 release from the alveolar bone matrix due to OC dysfunction may lead to osteopetrosis-associated root formation via impaired radicular odontoblast differentiation. As such, this study uncovers TGF-β1 /Smad2/3 as a key signaling pathway regulating odontoblast differentiation and tooth root formation and may contribute to future therapeutic approaches to tooth root regeneration.
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Affiliation(s)
- Jue Wang
- Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Abigail McVicar
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA
| | - Yilin Chen
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA
| | - Hong-Wen Deng
- Tulane Center of Biomedical Informatics and Genomics, Deming Department of Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Zhihe Zhao
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Wei Chen
- Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA.
| | - Yi-Ping Li
- Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA.
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Indrawinata K, Argiropoulos P, Sugita S. Structural and functional understanding of disease-associated mutations in V-ATPase subunit a1 and other isoforms. Front Mol Neurosci 2023; 16:1135015. [PMID: 37465367 PMCID: PMC10352029 DOI: 10.3389/fnmol.2023.1135015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 06/09/2023] [Indexed: 07/20/2023] Open
Abstract
The vacuolar-type ATPase (V-ATPase) is a multisubunit protein composed of the cytosolic adenosine triphosphate (ATP) hydrolysis catalyzing V1 complex, and the integral membrane complex, Vo, responsible for proton translocation. The largest subunit of the Vo complex, subunit a, enables proton translocation upon ATP hydrolysis, mediated by the cytosolic V1 complex. Four known subunit a isoforms (a1-a4) are expressed in different cellular locations. Subunit a1 (also known as Voa1), the neural isoform, is strongly expressed in neurons and is encoded by the ATP6V0A1 gene. Global knockout of this gene in mice causes embryonic lethality, whereas pyramidal neuron-specific knockout resulted in neuronal cell death with impaired spatial and learning memory. Recently reported, de novo and biallelic mutations of the human ATP6V0A1 impair autophagic and lysosomal activities, contributing to neuronal cell death in developmental and epileptic encephalopathies (DEE) and early onset progressive myoclonus epilepsy (PME). The de novo heterozygous R740Q mutation is the most recurrent variant reported in cases of DEE. Homology studies suggest R740 deprotonates protons from specific glutamic acid residues in subunit c, highlighting its importance to the overall V-ATPase function. In this paper, we discuss the structure and mechanism of the V-ATPase, emphasizing how mutations in subunit a1 can lead to lysosomal and autophagic dysfunction in neurodevelopmental disorders, and how mutations to the non-neural isoforms, a2-a4, can also lead to various genetic diseases. Given the growing discovery of disease-causing variants of V-ATPase subunit a and its function as a pump-based regulator of intracellular organelle pH, this multiprotein complex warrants further investigation.
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Affiliation(s)
- Karen Indrawinata
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Peter Argiropoulos
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Shuzo Sugita
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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4
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Zhou W, van Rooij JGJ, van de Laarschot DM, Zervou Z, Bruggenwirth H, Appelman‐Dijkstra NM, Ebeling PR, Demirdas S, Verkerk AJMH, Zillikens MC. Prevalence of Monogenic Bone Disorders in a Dutch Cohort of Atypical Femur Fracture Patients. J Bone Miner Res 2023; 38:896-906. [PMID: 37076969 PMCID: PMC10946469 DOI: 10.1002/jbmr.4801] [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: 03/21/2022] [Revised: 02/12/2023] [Accepted: 03/07/2023] [Indexed: 04/21/2023]
Abstract
Atypical femur fractures (AFFs), considered rare associations of bisphosphonates, have also been reported in patients with monogenic bone disorders without bisphosphonate use. The exact association between AFFs and monogenic bone disorders remains unknown. Our aim was to determine the prevalence of monogenic bone disorders in a Dutch AFF cohort. AFF patients were recruited from two specialist bone centers in the Netherlands. Medical records of the AFF patients were reviewed for clinical features of monogenic bone disorders. Genetic variants identified by whole-exome sequencing in 37 candidate genes involved in monogenic bone disorders were classified based on the American College of Medical Genetics and Genomics (ACMG) classification guidelines. Copy number variations overlapping the candidate genes were also evaluated using DNA array genotyping data. The cohort comprises 60 AFF patients (including a pair of siblings), with 95% having received bisphosphonates. Fifteen AFF patients (25%) had clinical features of monogenic bone disorders. Eight of them (54%), including the pair of siblings, had a (likely) pathogenic variant in either PLS3, COL1A2, LRP5, or ALPL. One patient carried a likely pathogenic variant in TCIRG1 among patients not suspected of monogenic bone disorders (2%). In total, nine patients in this AFF cohort (15%) had a (likely) pathogenic variant. In one patient, we identified a 12.7 Mb deletion in chromosome 6, encompassing TENT5A. The findings indicate a strong relationship between AFFs and monogenic bone disorders, particularly osteogenesis imperfecta and hypophosphatasia, but mainly in individuals with symptoms of these disorders. The high yield of (likely) pathogenic variants in AFF patients with a clinical suspicion of these disorders stresses the importance of careful clinical evaluation of AFF patients. Although the relevance of bisphosphonate use in this relationship is currently unclear, clinicians should consider these findings in medical management of these patients. © 2023 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)
- Wei Zhou
- Department of Internal MedicineErasmus MCRotterdamThe Netherlands
| | | | | | - Zografia Zervou
- Department of Internal MedicineErasmus MCRotterdamThe Netherlands
| | | | - Natasha M Appelman‐Dijkstra
- Department of Internal Medicine, Division of EndocrinologyLeiden University Medical CenterLeidenThe Netherlands
| | - Peter R Ebeling
- Department of MedicineSchool of Clinical Sciences, Monash UniversityClaytonAustralia
| | - Serwet Demirdas
- Department of Clinical GeneticsErasmus MCRotterdamThe Netherlands
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5
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El-Kamah GY, Mehrez MI, Taher MB, El-Bassyouni HT, Gaber KR, Amr KS. Outlining the Clinical Profile of TCIRG1 14 Variants including 5 Novels with Overview of ARO Phenotype and Ethnic Impact in 20 Egyptian Families. Genes (Basel) 2023; 14:genes14040900. [PMID: 37107657 PMCID: PMC10137576 DOI: 10.3390/genes14040900] [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: 11/29/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 04/29/2023] Open
Abstract
TCIRG1 gene mutations underlie osteopetrosis, a rare genetic disorder impacting osteoclast function with consequent brittle bones prone to fracture, in spite of being characterized by increased bone density. The disorder is known to exhibit marked genetic heterogeneity, has no treatment, and is lethal in most instances. There are reports of ethnic variations affecting bone mineral density and variants' expression as diverse phenotypes even within individuals descending from the same pedigree. We herein focus on one of osteopetrosis's three types: the autosomal recessive malignant form (MIM 259700) (ARO) that is almost always associated with severe clinical symptoms. We reviewed the results of about 1800 Egyptian exomes and we did not detect similar variants within our Egyptian dataset and secondary neurological deficit. We studied twenty Egyptian families: sixteen ARO patients, ten carrier parents with at least one ARO affected sib, and two fetuses. They were all subjected to thorough evaluation and TCIRG1 gene sequencing. Our results of twenty-eight individuals descending from twenty Egyptian pedigrees with at least one ARO patient, expand the phenotype as well as genotype spectrum of recessive mutations in the TCIRG1 gene by five novel pathogenic variants. Identifying TCIRG1 gene mutations in Egyptian patients with ARO allowed the provision of proper genetic counseling, carrier detection, and prenatal diagnosis starting with two families included herein. It also could pave the way to modern genomic therapeutic approaches.
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Affiliation(s)
- Ghada Y El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Mennat I Mehrez
- Oro-Dental Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Mohamed B Taher
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Hala T El-Bassyouni
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Khaled R Gaber
- Prenatal Diagnosis and Fetal Medicine Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
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6
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Pillai NR, Aggarwal A, Orchard P. Phenotype-autosomal recessive osteopetrosis. Bone 2022; 165:116577. [PMID: 36195244 DOI: 10.1016/j.bone.2022.116577] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 11/02/2022]
Abstract
Osteopetrosis (OPT) is a life-threatening disease characterized by increased bone mass caused by diminished osteoclast function/differentiation. The autosomal recessive forms, caused by biallelic variants in implicated genes, usually present in infancy. Without treatment, autosomal recessive OPTs are usually fatal within the first 10 years of life [1]. Here, we review the clinical features and associated pathophysiology of the autosomal recessive OPT. A greater understanding of these rare disorders will advance early diagnosis and optimal management.
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Affiliation(s)
- Nishitha R Pillai
- Division of Genetics and Metabolism, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
| | - Anjali Aggarwal
- Division of Genetics and Metabolism, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Paul Orchard
- Division of Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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7
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Capo V, Abinun M, Villa A. Osteoclast rich osteopetrosis due to defects in the TCIRG1 gene. Bone 2022; 165:116519. [PMID: 35981697 DOI: 10.1016/j.bone.2022.116519] [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] [Received: 06/15/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/28/2022]
Abstract
Discovery that mutations in TCIRG1 (also known as Atp6i) gene are responsible for most instances of autosomal recessive osteopetrosis (ARO) heralded a new era for comprehension and treatment of this phenotypically heterogeneous rare bone disease. TCIRG1 encodes the a3 subunit, an essential isoform of the vacuolar ATPase proton pump involved in acidification of the osteoclast resorption lacuna and in secretory lysosome trafficking. TCIRG1 defects lead to inefficient bone resorption by nonfunctional osteoclasts seen in abundance on bone marrow biopsy, delineating this ARO as 'osteoclast-rich'. Presentation is usually in early childhood and features of extramedullary haematopoiesis (hepatosplenomegaly, anaemia, thrombocytopenia) due to bone marrow fibrosis, and cranial nerve impingement (blindness in particular). Impaired dietary calcium uptake due to high pH causes the co-occurrence of rickets, described as "osteopetrorickets". Osteoclast dysfunction leads to early death if untreated, and allogeneic haematopoietic stem cell transplantation is currently the treatment of choice. Studies of patients as well as of mouse models carrying spontaneous (the oc/oc mouse) or targeted disruption of Atp6i (TCIRG1) gene have been instrumental providing insight into disease pathogenesis and development of novel cellular therapies that exploit gene correction.
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Affiliation(s)
- Valentina Capo
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy; Institute of Genetic and Biomedical Research, Milan Unit, National Research Council, Milan, Italy
| | - Mario Abinun
- Children's Haematopoietic Stem Cell Transplantation Unit, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Anna Villa
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy; Institute of Genetic and Biomedical Research, Milan Unit, National Research Council, Milan, Italy.
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8
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Vacher J. OSTM1 pleiotropic roles from osteopetrosis to neurodegeneration. Bone 2022; 163:116505. [PMID: 35902071 DOI: 10.1016/j.bone.2022.116505] [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] [Received: 06/07/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
Abstract
Autosomal recessive osteopetroses (ARO) are rare genetic skeletal disorders of high clinical and molecular heterogeneity with an estimated frequency of 1:250,000 worldwide. The manifestations are diverse and although individually rare, the various forms contribute to the prevalence of a significant number of affected individuals with considerable morbidity and mortality. Among the ARO classification, the most severe form is the autosomal recessive-5 (OPTB5) osteopetrosis (OMIM 259720) that results from homozygous mutation in the OSTM1 gene (607649). OSTM1 mutations account for approximately 5 % of instances of autosomal recessive osteopetrosis and lead to a highly debilitating form of the disease in infancy and death within the first few years of life (Sobacchi et al., 2013) [1].
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Affiliation(s)
- Jean Vacher
- Institut de Recherches Cliniques de Montréal (IRCM), 110 avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada; Département de Médecine, Université de Montréal, Montréal, Québec, Canada.
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9
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Heo SC, You JC, Jung S, Kim YN, Shin SH, Lee JY, Kim HJ. Pim-2 regulates bone resorptive activity of osteoclasts via V-ATPase a3 isoform expression in periodontal disease. J Cell Physiol 2022; 237:3381-3393. [PMID: 35696529 DOI: 10.1002/jcp.30814] [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: 01/25/2022] [Revised: 05/08/2022] [Accepted: 05/19/2022] [Indexed: 11/07/2022]
Abstract
Cytoplasmic serine/threonine Pim kinases have emerged as important modulators of immune regulation and oncology. However, their regulatory roles in bone remodeling remain obscure. Here, we aimed to determine the roles of Pim kinases in periodontal disease (PD), focusing on the regulation of osteoclastogenesis and bone resorptive activity. We investigated Pim kinases expression in PD by analyzing data from the online Gene Expression Omnibus database and using ligature-induced periodontitis mouse model. The expression of Pim kinases during receptor activator of nuclear factor kB ligand (RANKL)-induced osteoclastogenesis was assessed in mouse bone marrow-derived macrophages (BMMs) using reverse transcription polymerase chain reaction. Osteoclast differentiation and bone resorption activity were respectively verified by tartrate-resistant acid phosphatase staining and dentin disc-based bone resorption assays. We silenced and overexpressed Pim-2 using small interfering RNA (siRNA) and retroviral vector, respectively, to investigate the molecular mechanisms underlying Pim-2 regulation in RANKL-induced osteoclastogenesis and bone resorption activity. Upregulated expression of Pim-2 was observed in both patients with PD and periodontitis-affected mouse gingival tissues. siRNA-mediated silencing of Pim-2 in BMMs diminished RANKL-induced resorptive activity without affecting osteoclastogenesis. Moreover, RANKL-triggered stimulation of a3 isoform, which is a subunit of vacuolar-type ATPase, was selectively attenuated in BMMs on silencing Pim-2. The overexpression of Pim-2 with a retroviral vector stimulated the a3 subunit, thus inducing bone resorption activity. Taken together, these results suggest that Pim-2 acts as a major modulator of osteoclastic activity by regulating a3 isoform expression in PD.
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Affiliation(s)
- Soon C Heo
- Department of Oral Physiology, Periodontal Diseases Signaling Network Research Center, Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, South Korea
| | - Jae C You
- Department of Oral and Maxillofacial Surgery, Dental Research Institute and Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, South Korea
| | - Suhan Jung
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, School of Dentistry, Seoul, South Korea
| | - Yu N Kim
- Department of Oral Physiology, Periodontal Diseases Signaling Network Research Center, Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, South Korea
| | - Sang-Hun Shin
- Department of Oral and Maxillofacial Surgery, Dental Research Institute and Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, South Korea
| | - Jae-Yeol Lee
- Department of Oral and Maxillofacial Surgery, Dental Research Institute and Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, South Korea
| | - Hyung J Kim
- Department of Oral Physiology, Periodontal Diseases Signaling Network Research Center, Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, South Korea
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Shinwari K, Rehman HM, Liu G, Bolkov MA, Tuzankina IA, Chereshnev VA. Novel Disease-Associated Missense Single-Nucleotide Polymorphisms Variants Predication by Algorithms Tools and Molecular Dynamics Simulation of Human TCIRG1 Gene Causing Congenital Neutropenia and Osteopetrosis. Front Mol Biosci 2022; 9:879875. [PMID: 35573728 PMCID: PMC9095858 DOI: 10.3389/fmolb.2022.879875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/04/2022] [Indexed: 12/16/2022] Open
Abstract
T Cell Immune Regulator 1, ATPase H + Transporting V0 Subunit A3 (TCIRG1 gene provides instructions for making one part, the a3 subunit, of a large protein complex known as a vacuolar H + -ATPase (V-ATPase). V-ATPases are a group of similar complexes that act as pumps to move positively charged hydrogen atoms (protons) across membranes. Single amino acid changes in highly conserved areas of the TCIRG1 protein have been linked to autosomal recessive osteopetrosis and severe congenital neutropenia. We used multiple computational approaches to classify disease-prone single nucleotide polymorphisms (SNPs) in TCIRG1. We used molecular dynamics analysis to identify the deleterious nsSNPs, build mutant protein structures, and assess the impact of mutation. Our results show that fifteen nsSNPs (rs199902030, rs200149541, rs372499913, rs267605221, rs374941368, rs375717418, rs80008675, rs149792489, rs116675104, rs121908250, rs121908251, rs121908251, rs149792489 and rs116675104) variants are likely to be highly deleterious mutations as by incorporating them into wild protein they destabilize the wild protein structure and function. They are also located in the V-ATPase I domain, which may destabilize the structure and impair TCIRG1 protein activation, as well as reduce its ATPase effectiveness. These mutants have not yet been identified in patients suffering from CN and osteopetrosis while (G405R, R444L, and D517N) reported in our study are already associated with osteopetrosis. Mutation V52L reported in our study was identified in a patient suspected for CN. Finally, these mutants can help to further understand the broad pool of illness susceptibilities associated with TCIRG1 catalytic kinase domain activation and aid in the development of an effective treatment for associated diseases.
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Affiliation(s)
- Khyber Shinwari
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- *Correspondence: Khyber Shinwari,
| | - Hafiz Muzzammel Rehman
- School of Biochemistry and Biotechnology, University of the Punjab, Lahore, Pakistan
- Alnoorians Group of Institutes, Shad Bagh, Lahore, Pakistan
| | - Guojun Liu
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China
| | - Mikhail A. Bolkov
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
| | - Irina A. Tuzankina
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
| | - Valery. A. Chereshnev
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
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11
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Overlapping Phenotypes in Osteopetrosis and Pycnodysostosis in Asian-Indians. Case Rep Genet 2021; 2021:7133508. [PMID: 34777883 PMCID: PMC8580671 DOI: 10.1155/2021/7133508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 10/04/2021] [Indexed: 11/17/2022] Open
Abstract
Osteopetrosis is a disorder characterized by high bone density, hepatosplenomegaly, visual and hearing loss, and anemia. Pycnodysostosis presents with short stature, acroosteolysis, and dense bones. We, hereby, present here a family with autosomal dominant osteopetrosis and also children with recessive osteopetrosis and pycnodysostosis. The molecular confirmation was done in 3 cases. Genetic heterogeneity in clinical presentation is discussed here. Further studies will help in identifying epigenetic alterations and population-specific variants and also developing targeted therapies.
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Liu C, Ajmal M, Akram Z, Ghafoor T, Farhan M, Shafique S, Wahid S, Bano S, Xiao J, Satti HS, Zhang F, Khan TN. Genetic analysis of osteopetrosis in Pakistani families identifies novel and known sequence variants. BMC Med Genomics 2021; 14:264. [PMID: 34753502 PMCID: PMC8576874 DOI: 10.1186/s12920-021-01117-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/26/2021] [Indexed: 11/28/2022] Open
Abstract
Osteopetrosis is a genetically heterogenous, fatal bone disorder characterized by increased bone density. Globally, various genetic causes are reported for osteopetrosis with all forms of inheritance patterns. A precise molecular diagnosis is necessary for prognosis and for prescribing treatment paradigms in osteopetrosis. Here we report on thirteen individuals diagnosed with infantile malignant osteopetrosis coming from ten unrelated Pakistani families; nine of whom are consanguineous. We performed whole exome sequencing and Sanger sequencing in all families and identified homozygous variants in genes previously reported for autosomal recessive inheritance of osteopetrosis. All the identified variants are expected to affect the stability or length of gene products except one nonsynonymous missense variant. TCIRG1 was found as a candidate causal gene in majority of the families. We report six novel variants; four in TCIRG1 and one each in CLCN7 and OSTM1. Our combined findings will be helpful in molecular diagnosis and genetic counselling of patients with osteopetrosis particularly in populations with high consanguinity.
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Affiliation(s)
- Chunyu Liu
- Obstetrics and Gynecology Hospital, NHC Key Laboratory of Reproduction Regulation (Shanghai Institute for Biomedical and Pharmaceutical Technologies), School of Life Sciences, Fudan University, Shanghai, 200011, China
| | - Muhammad Ajmal
- Institute of Biomedical and Genetic Engineering, Islamabad, 44000, Pakistan
| | - Zaineb Akram
- Armed Forces Bone Marrow Transplant Centre, CMH Medical Complex, Rawalpindi, 46000, Pakistan
| | - Tariq Ghafoor
- Armed Forces Bone Marrow Transplant Centre, CMH Medical Complex, Rawalpindi, 46000, Pakistan
| | - Muhammad Farhan
- Armed Forces Bone Marrow Transplant Centre, CMH Medical Complex, Rawalpindi, 46000, Pakistan
| | - Sobia Shafique
- Institute of Biomedical and Genetic Engineering, Islamabad, 44000, Pakistan
| | - Sughra Wahid
- KRL General Hospital, Islamabad, 44000, Pakistan
| | - Shahar Bano
- KRL General Hospital, Islamabad, 44000, Pakistan
| | - Jianqiu Xiao
- Division of Bone and Mineral Diseases, Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Humayoon Shafique Satti
- Department of Biological Sciences, National University of Medical Sciences, Rawalpindi, 46000, Pakistan
| | - Feng Zhang
- Obstetrics and Gynecology Hospital, NHC Key Laboratory of Reproduction Regulation (Shanghai Institute for Biomedical and Pharmaceutical Technologies), School of Life Sciences, Fudan University, Shanghai, 200011, China.
| | - Tahir Naeem Khan
- Department of Biological Sciences, National University of Medical Sciences, Rawalpindi, 46000, Pakistan. .,National Institute of Advance Studies and Research, National University of Medical Sciences, Rawalpindi, 46000, Pakistan.
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13
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Trojani MC, Santucci-Darmanin S, Breuil V, Carle GF, Pierrefite-Carle V. Autophagy and bone diseases. Joint Bone Spine 2021; 89:105301. [PMID: 34673234 DOI: 10.1016/j.jbspin.2021.105301] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 12/13/2022]
Abstract
Autophagy is a ubiquitous cellular process, allowing the removal and recycling of damaged proteins and organelles. At the basal level, this process plays a role in quality control, thus participating in cellular homeostasis. Autophagy can also be induced by various stresses, such as nutrient deprivation or hypoxia, to allow the cell to survive until conditions improve. In recent years, the role of this process has been widely studied in many pathologies such as neurodegenerative diseases or cancers. In bone tissue, various studies have shown that autophagy is involved in the survival, differentiation and activity of osteoblasts, osteocytes and osteoclasts. The evolution of this knowledge has led to the identification of new molecular pathophysiological mechanisms in bone pathologies. This review reports the current state of knowledge on the role of autophagy in 4 bone diseases: osteoporosis, which seems to be associated with a decrease in autophagy, osteopetrosis and Paget's disease where the course of the autophagic process is disturbed, and finally osteosarcoma where autophagy seems to play a protumoral role. A better understanding of the involvement of autophagy in these pathologies should eventually lead to the identification of new potential therapeutic targets.
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Affiliation(s)
- Marie-Charlotte Trojani
- UMR E-430 TIRO-MATOS CEA/DRF Institut Joliot, faculté de médecine de Nice, université Nice Côte d'Azur, 28, avenue de Valombrose, 06107 Nice cedex 2, France; Service de rhumatologie, CHU de Nice, Nice, France
| | - Sabine Santucci-Darmanin
- UMR E-430 TIRO-MATOS CEA/DRF Institut Joliot, faculté de médecine de Nice, université Nice Côte d'Azur, 28, avenue de Valombrose, 06107 Nice cedex 2, France
| | - Véronique Breuil
- UMR E-430 TIRO-MATOS CEA/DRF Institut Joliot, faculté de médecine de Nice, université Nice Côte d'Azur, 28, avenue de Valombrose, 06107 Nice cedex 2, France; Service de rhumatologie, CHU de Nice, Nice, France
| | - Georges F Carle
- UMR E-430 TIRO-MATOS CEA/DRF Institut Joliot, faculté de médecine de Nice, université Nice Côte d'Azur, 28, avenue de Valombrose, 06107 Nice cedex 2, France
| | - Valérie Pierrefite-Carle
- UMR E-430 TIRO-MATOS CEA/DRF Institut Joliot, faculté de médecine de Nice, université Nice Côte d'Azur, 28, avenue de Valombrose, 06107 Nice cedex 2, France; Inserm, Paris, France.
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14
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Liang H, Li N, Yao RE, Yu T, Ding L, Chen J, Wang J. Clinical and molecular characterization of five Chinese patients with autosomal recessive osteopetrosis. Mol Genet Genomic Med 2021; 9:e1815. [PMID: 34545712 PMCID: PMC8606217 DOI: 10.1002/mgg3.1815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/27/2021] [Accepted: 09/07/2021] [Indexed: 11/08/2022] Open
Abstract
Background Osteopetrosis is characterized by increased bone density and bone marrow cavity stenosis due to a decrease in the number of osteoclasts or the dysfunction of their differentiation and absorption properties usually caused by biallelic variants of the TCIRG1 and CLCN7 genes. Methods In this study, we describe five Chinese children who presented with anemia, thrombocytopenia, hepatosplenomegaly, repeated infections, and increased bone density. Whole‐exome sequencing identified five compound heterozygous variants of the CLCN7 and TCIRG1 genes in these patients. Results Patient 1 had a novel variant c.1555C>T (p.L519F) and a previously reported pathogenic variant c.2299C>T (p.R767W) in CLCN7. Patient 2 harbored a novel missense variant (c.1025T>C; p.L342P) and a novel splicing variant (c.286‐9G>A) in CLCN7. Patients 3A and 3B from one family displayed the same compound heterozygous TCIRG1 variant, including a novel frameshift variant (c.1370del; p.T457Tfs*71) and a novel splicing variant (c.1554+2T>C). In Patient 4, two novel variants were identified in the TCIRG1 gene: c.676G>T; p.E226* and c.1191del; p.P398Sfs*5. Patient 5 harbored two known pathogenic variants, c.909C>A (p.Y303*) and c.2008C>T (p.R670*), in TCIRG1. Analysis of the products obtained from the reverse transcription‐polymerase chain reaction revealed that the c.286‐9G>A variant in CLCN7 of patient 2 leads to intron 3 retention, resulting in the formation of a premature termination codon (p.E95Vfs*8). These five patients were eventually diagnosed with autosomal recessive osteopetrosis, and the three children with TCIRG1 variants received hematopoietic stem cell transplantation. Conclusions Our results expand the spectrum of variation of genes related to osteopetrosis and deepen the understanding of the relationship between the genotype and clinical characteristics of osteopetrosis.
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Affiliation(s)
- Huanhuan Liang
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health, Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Niu Li
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
| | - Ru-En Yao
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
| | - Tingting Yu
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
| | - Lixia Ding
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health, Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Chen
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health, Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wang
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
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15
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Oh YK, Choi KE, Shin YJ, Kim ER, Kim JY, Kim MS, Cho SY, Jin DK. Autosomal Recessive Malignant Infantile Osteopetrosis Associated with a TCIRG1 Mutation: A Case Report of a Neonate Presenting with Hypocalcemia in South Korea. NEONATAL MEDICINE 2021. [DOI: 10.5385/nm.2021.28.3.133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Osteopetrosis refers to a group of genetic skeletal disorders characterized by osteosclerosis and fragile bones. Osteopetrosis can be classified into autosomal dominant, autosomal recessive, or X-linked forms, which might differ in clinical characteristics and disease severity. Autosomal recessive osteopetrosis, also known as malignant osteopetrosis, has an earlier onset, more serious clinical symptoms, and is usually fatal. We encountered a 1-day-old girl who was born full-term via vaginal delivery, which was complicated by meconium-stained amniotic fluid, cephalo-pelvic disproportion, and nuchal cord. Routine neonatal care was provided, in addition to blood tests and chest radiography to screen for sepsis, as well as skull radiography to rule out head injuries. Initial blood tests revealed hypocalcemia, which persisted on follow-up tests the next day. Radiographic examinations revealed diffusely increased bone density and a "space alien" appearance of the skull. Based on radiographic and laboratory findings, the infantile form of osteopetrosis was suspected and genetic testing for identification of the responsible gene. Eventually, a heterozygous mutation of the T cell immune regulator 1, ATPase H+ transporting V0 subunit a3 (TCIRG1) gene (c.292C>T) was identified, making this the first reported case of neonatal-onset malignant osteopetrosis with TCIRG1 mutation in South Korea. Early-onset hypocalcemia is common and usually results from prematurity, fetal growth restriction, maternal diabetes, perinatal asphyxia, and physiologic hypoparathyroidism. However, if hypocalcemia persists, we recommend considering 'infantile of osteopetrosis' as a rare cause of neonatal hypocalcemia and performing radiographic examinations to establish the diagnosis.
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16
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Wu P, Cai Z, Jiang WH, Lu G, Wu PQ, Xie ZW, Peng JZ, Chen C, Qi JY, Xu LZ, Shen KL, Zeng HS, Yin GQ. Two novel mutations in TCIRG1 induced infantile malignant osteopetrosis: a case report. BMC Pediatr 2021; 21:297. [PMID: 34210262 PMCID: PMC8246672 DOI: 10.1186/s12887-021-02774-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/14/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Infantile malignant osteopetrosis (IMO) is a rare autosomal recessive disease characterized by a higher bone density in bone marrow caused by the dysfunction of bone resorption. Clinically, IMO can be diagnosed with medical examination, bone mineral density test and whole genome sequencing. CASE PRESENTATION We present the case of a 4-month-old male infant with abnormal skull development, hypocalcemia and premature closure of the cranial sutures. Due to the hyper bone density showed by his radiographic examination, which are characteristic patterns of IMO, we speculated that he might be an IMO patient. In order to confirm this diagnosis, a high-precision whole exome sequencing of the infant and his parents was performed. The analysis of high-precision whole exome sequencing results lead to the identification of two novel heterozygous mutations c.504-1G > C (a splicing site mutation) and c.1371delC (p.G458Afs*70, a frameshift mutation) in gene TCIRG1 derived from his parents. Therefore, we propose that there is a close association between these two mutations and the onset of IMO. CONCLUSIONS To date, these two novel mutations in gene TCIRG1 have not been reported in the reference gene database of Chinese population. These variants have likewise not been reported outside of China in the Genome Aggregation Database (gnomAD). Our case suggests that the use of whole exome sequencing to detect these two mutations will improve the identification and early diagnosis of IMO, and more specifically, the identification of homozygous individuals with TCIRG1 gene mutation. We propose that these mutations in gene TCIRG1 could be a novel therapeutic target for the IMO in the future.
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Affiliation(s)
- Ping Wu
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
- Department of Respirology, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China
- Department of Allergy, Immunology and Rheumatology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Zhe Cai
- Department of Allergy, Immunology and Rheumatology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou, 510623, China
- Institute Pasteur of Shanghai, Chinese Academy of Science, Shanghai, 200031, China
- Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
| | - Wen-Hui Jiang
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Gen Lu
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Pei-Qiong Wu
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Zhi-Wei Xie
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Jun-Zheng Peng
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Chen Chen
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Jun-Ye Qi
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Li-Zhen Xu
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Kun-Ling Shen
- Department of Respirology, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China
| | - Hua-Song Zeng
- Department of Allergy, Immunology and Rheumatology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Gen-Quan Yin
- Department of Respirology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510120, Guangdong, China.
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Chu A, Zirngibl RA, Manolson MF. The V-ATPase a3 Subunit: Structure, Function and Therapeutic Potential of an Essential Biomolecule in Osteoclastic Bone Resorption. Int J Mol Sci 2021; 22:ijms22136934. [PMID: 34203247 PMCID: PMC8269383 DOI: 10.3390/ijms22136934] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/29/2022] Open
Abstract
This review focuses on one of the 16 proteins composing the V-ATPase complex responsible for resorbing bone: the a3 subunit. The rationale for focusing on this biomolecule is that mutations in this one protein account for over 50% of osteopetrosis cases, highlighting its critical role in bone physiology. Despite its essential role in bone remodeling and its involvement in bone diseases, little is known about the way in which this subunit is targeted and regulated within osteoclasts. To this end, this review is broadened to include the three other mammalian paralogues (a1, a2 and a4) and the two yeast orthologs (Vph1p and Stv1p). By examining the literature on all of the paralogues/orthologs of the V-ATPase a subunit, we hope to provide insight into the molecular mechanisms and future research directions specific to a3. This review starts with an overview on bone, highlighting the role of V-ATPases in osteoclastic bone resorption. We then cover V-ATPases in other location/functions, highlighting the roles which the four mammalian a subunit paralogues might play in differential targeting and/or regulation. We review the ways in which the energy of ATP hydrolysis is converted into proton translocation, and go in depth into the diverse role of the a subunit, not only in proton translocation but also in lipid binding, cell signaling and human diseases. Finally, the therapeutic implication of targeting a3 specifically for bone diseases and cancer is discussed, with concluding remarks on future directions.
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18
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Moscatelli I, Almarza E, Schambach A, Ricks D, Schulz A, Herzog CD, Henriksen K, Askmyr M, Schwartz JD, Richter J. Gene therapy for infantile malignant osteopetrosis: review of pre-clinical research and proof-of-concept for phenotypic reversal. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 20:389-397. [PMID: 33575431 PMCID: PMC7848732 DOI: 10.1016/j.omtm.2020.12.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Infantile malignant osteopetrosis is a devastating disorder of early childhood that is frequently fatal and for which there are only limited therapeutic options. Gene therapy utilizing autologous hematopoietic stem and progenitor cells represents a potentially advantageous therapeutic alternative for this multisystemic disease. Gene therapy can be performed relatively rapidly following diagnosis, will not result in graft versus host disease, and may also have potential for reduced incidences of other transplant-related complications. In this review, we have summarized the past sixteen years of research aimed at developing a gene therapy for infantile malignant osteopetrosis; these efforts have culminated in the first clinical trial employing lentiviral-mediated delivery of TCIRG1 in autologous hematopoietic stem and progenitor cells.
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Affiliation(s)
- Ilana Moscatelli
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, Lund, Sweden
| | | | - Axel Schambach
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany.,Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - David Ricks
- Rocket Pharmaceuticals, Inc., New York, NY, USA
| | - Ansgar Schulz
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Germany
| | | | | | - Maria Askmyr
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, Lund, Sweden
| | | | - Johan Richter
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, Lund, Sweden
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19
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Santos-Pereira C, Rodrigues LR, Côrte-Real M. Emerging insights on the role of V-ATPase in human diseases: Therapeutic challenges and opportunities. Med Res Rev 2021; 41:1927-1964. [PMID: 33483985 DOI: 10.1002/med.21782] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 12/05/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022]
Abstract
The control of the intracellular pH is vital for the survival of all organisms. Membrane transporters, both at the plasma and intracellular membranes, are key players in maintaining a finely tuned pH balance between intra- and extracellular spaces, and therefore in cellular homeostasis. V-ATPase is a housekeeping ATP-driven proton pump highly conserved among prokaryotes and eukaryotes. This proton pump, which exhibits a complex multisubunit structure based on cell type-specific isoforms, is essential for pH regulation and for a multitude of ubiquitous and specialized functions. Thus, it is not surprising that V-ATPase aberrant overexpression, mislocalization, and mutations in V-ATPase subunit-encoding genes have been associated with several human diseases. However, the ubiquitous expression of this transporter and the high toxicity driven by its off-target inhibition, renders V-ATPase-directed therapies very challenging and increases the need for selective strategies. Here we review emerging evidence linking V-ATPase and both inherited and acquired human diseases, explore the therapeutic challenges and opportunities envisaged from recent data, and advance future research avenues. We highlight the importance of V-ATPases with unique subunit isoform molecular signatures and disease-associated isoforms to design selective V-ATPase-directed therapies. We also discuss the rational design of drug development pipelines and cutting-edge methodological approaches toward V-ATPase-centered drug discovery. Diseases like cancer, osteoporosis, and even fungal infections can benefit from V-ATPase-directed therapies.
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Affiliation(s)
- Cátia Santos-Pereira
- Department of Biology, Centre of Molecular and Environmental Biology (CBMA), University of Minho, Braga, Portugal.,Department of Biological Engineering, Centre of Biological Engineering (CEB), University of Minho, Braga, Portugal
| | - Lígia R Rodrigues
- Department of Biological Engineering, Centre of Biological Engineering (CEB), University of Minho, Braga, Portugal
| | - Manuela Côrte-Real
- Department of Biology, Centre of Molecular and Environmental Biology (CBMA), University of Minho, Braga, Portugal
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20
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Osteopetrosis in a six-month-old infant. J Hematop 2020. [DOI: 10.1007/s12308-020-00399-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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21
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Xian X, Moraghebi R, Löfvall H, Fasth A, Henriksen K, Richter J, Woods NB, Moscatelli I. Generation of gene-corrected functional osteoclasts from osteopetrotic induced pluripotent stem cells. Stem Cell Res Ther 2020; 11:179. [PMID: 32414402 PMCID: PMC7227215 DOI: 10.1186/s13287-020-01701-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/03/2020] [Accepted: 04/30/2020] [Indexed: 12/28/2022] Open
Abstract
Background Infantile malignant osteopetrosis (IMO) is an autosomal recessive disorder characterized by non-functional osteoclasts and a fatal outcome early in childhood. About 50% of patients have mutations in the TCIRG1 gene. Methods IMO iPSCs were generated from a patient carrying a homozygous c.11279G>A (IVS18+1) mutation in TCIRG1 and transduced with a lentiviral vector expressing human TCIRG1. Embryoid bodies were generated and differentiated into monocytes. Non-adherent cells were harvested and further differentiated into osteoclasts on bovine bone slices. Results Release of the bone resorption biomarker CTX-I into the media of gene-corrected osteoclasts was 5-fold higher than that of the uncorrected osteoclasts and 35% of that of control osteoclasts. Bone resorption potential was confirmed by the presence of pits on the bones cultured with gene-corrected osteoclasts, absent in the uncorrected IMO osteoclasts. Conclusions The disease phenotype was partially corrected in vitro, providing a valuable resource for therapy development for this form of severe osteopetrosis.
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Affiliation(s)
- Xiaojie Xian
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, BMC A12, 221 84, Lund, Sweden
| | - Roksana Moraghebi
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, BMC A12, 221 84, Lund, Sweden
| | - Henrik Löfvall
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, BMC A12, 221 84, Lund, Sweden.,Nordic Bioscience, Herlev, Denmark
| | - Anders Fasth
- Department of Pediatrics, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden
| | | | - Johan Richter
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, BMC A12, 221 84, Lund, Sweden
| | - Niels-Bjarne Woods
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, BMC A12, 221 84, Lund, Sweden
| | - Ilana Moscatelli
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, Lund University, BMC A12, 221 84, Lund, Sweden.
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22
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Song Q, Meng B, Xu H, Mao Z. The emerging roles of vacuolar-type ATPase-dependent Lysosomal acidification in neurodegenerative diseases. Transl Neurodegener 2020; 9:17. [PMID: 32393395 PMCID: PMC7212675 DOI: 10.1186/s40035-020-00196-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/23/2020] [Indexed: 12/15/2022] Open
Abstract
Background Lysosomes digest extracellular material from the endocytic pathway and intracellular material from the autophagic pathway. This process is performed by the resident hydrolytic enzymes activated by the highly acidic pH within the lysosomal lumen. Lysosome pH gradients are mainly maintained by the vacuolar (H+) ATPase (or V-ATPase), which pumps protons into lysosomal lumen by consuming ATP. Dysfunction of V-ATPase affects lysosomal acidification, which disrupts the clearance of substrates and leads to many disorders, including neurodegenerative diseases. Main body As a large multi-subunit complex, the V-ATPase is composed of an integral membrane V0 domain involved in proton translocation and a peripheral V1 domain catalyzing ATP hydrolysis. The canonical functions of V-ATPase rely on its H+-pumping ability in multiple vesicle organelles to regulate endocytic traffic, protein processing and degradation, synaptic vesicle loading, and coupled transport. The other non-canonical effects of the V-ATPase that are not readily attributable to its proton-pumping activity include membrane fusion, pH sensing, amino-acid-induced activation of mTORC1, and scaffolding for protein-protein interaction. In response to various stimuli, V-ATPase complex can reversibly dissociate into V1 and V0 domains and thus close ATP-dependent proton transport. Dysregulation of pH and lysosomal dysfunction have been linked to many human diseases, including neurodegenerative disorders such as Alzheimer disease, Parkinson’s disease, amyotrophic lateral sclerosis as well as neurodegenerative lysosomal storage disorders. Conclusion V-ATPase complex is a universal proton pump and plays an important role in lysosome acidification in all types of cells. Since V-ATPase dysfunction contributes to the pathogenesis of multiple neurodegenerative diseases, further understanding the mechanisms that regulate the canonical and non-canonical functions of V-ATPase will reveal molecular details of disease process and help assess V-ATPase or molecules related to its regulation as therapeutic targets.
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Affiliation(s)
- Qiaoyun Song
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Reproductive Genetics, Hebei General Hospital, Shijiazhuang, Hebei Province, 050051, People's Republic of China.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Bo Meng
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Haidong Xu
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Zixu Mao
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA. .,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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23
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Chen W, Twaroski K, Eide C, Riddle MJ, Orchard PJ, Tolar J. TCIRG1 Transgenic Rescue of Osteoclast Function Using Induced Pluripotent Stem Cells Derived from Patients with Infantile Malignant Autosomal Recessive Osteopetrosis. J Bone Joint Surg Am 2019; 101:1939-1947. [PMID: 31567691 DOI: 10.2106/jbjs.19.00558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Osteoclasts are hematopoietic stem cell-derived multinucleated cells necessary for bone remodeling and resorption. TCIRG1 encodes a protein that is an adenosine triphosphate (ATP)-dependent vacuolar proton pump required for this process. Recessive loss-of-function mutations in both copies of this gene lead to impairment of osteoclast function, with increased bone density, increased skeletal mass, and early mortality. METHODS We isolated fibroblasts from a patient with the compound heterozygous TCIRG1 mutations c.1549G>A (p.517D>N) and c.2236C>T (p.746Q>X), and reprogrammed them into iPS (induced pluripotent stem) cells. The function of osteoclasts derived from these cells was then rescued by transgenic expression of TCIRG1 cDNA. RESULTS In addition to the known effects of TCIRG1 loss of function, iPS cell-derived osteoclasts from this patient had reduced expression of the bone remodeling enzymes cathepsin K (CTSK) and tartrate-resistant acid phosphatase (TRAP), leading to reduced in vitro bone remodeling. Expression of both genes and pit formation were restored in iPS cell-derived osteoclasts following transgenic restoration of TCIRG1 expression. CONCLUSIONS Transgenic overexpression of TCIRG1 was sufficient to restore osteoclast function in iPS cell-derived osteoclasts from a patient with infantile malignant autosomal-recessive osteopetrosis. CLINICAL RELEVANCE This work provides a proof of concept for an autologous approach to treating osteopetrosis, potentially avoiding the risks associated with hematopoietic stem cell transplantation in a young patient population.
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Affiliation(s)
- Weili Chen
- Stem Cell Institute (W.C., K.T., and J.T.) and Division of Blood and Marrow Transplantation (C.E., M.J.R., P.J.O., and J.T.), Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Kirk Twaroski
- Stem Cell Institute (W.C., K.T., and J.T.) and Division of Blood and Marrow Transplantation (C.E., M.J.R., P.J.O., and J.T.), Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Cindy Eide
- Stem Cell Institute (W.C., K.T., and J.T.) and Division of Blood and Marrow Transplantation (C.E., M.J.R., P.J.O., and J.T.), Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Megan J Riddle
- Stem Cell Institute (W.C., K.T., and J.T.) and Division of Blood and Marrow Transplantation (C.E., M.J.R., P.J.O., and J.T.), Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Paul J Orchard
- Stem Cell Institute (W.C., K.T., and J.T.) and Division of Blood and Marrow Transplantation (C.E., M.J.R., P.J.O., and J.T.), Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Jakub Tolar
- Stem Cell Institute (W.C., K.T., and J.T.) and Division of Blood and Marrow Transplantation (C.E., M.J.R., P.J.O., and J.T.), Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
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TCIRG1 and SNX10 gene mutations in the patients with autosomal recessive osteopetrosis. Gene 2019; 702:83-88. [PMID: 30898715 DOI: 10.1016/j.gene.2019.02.088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/08/2019] [Accepted: 02/25/2019] [Indexed: 11/21/2022]
Abstract
Autosomal recessive osteopetrosis (ARO) is a rare genetic bone disease characterized by dense and fragile bone, caused by a defect in osteoclasts responsible for the bone destruction. In this study, we aimed to investigate the mutations in TCIRG1 and SNX10 that are responsible for 50% and 4% of the cases, respectively. All amplicons were sequenced by Sanger sequencing following PCR amplification. As a result, six different mutations of the TCIRG1 gene were found in five of the twelve unrelated cases. These include two novel mutations, namely c.630 + 1G > T mutation and c.1778_1779delTG mutation of the gene which are identified as homozygous. A compound heterozygosity of known mutations c.649_674del26 and c.1372G > A and homozygous presence of the known c.2235 + 1G > A mutation were also observed in different patients. In addition, as a result of the prenatal testing in a family with osteopetrosis infant, the c.1674-1G > A mutation was detected as homozygous for the fetus. In TCIRG1, c.166C > T change, which is indicated as likely benign according to ClinVar database, was heterozygous. Several known polymorphisms; c.117 + 83 T > C, c.417 + 11A > G and c.714-19C > A in TCIRG1 gene; c.24 + 36 T > A and c.112-84G > A in SNX10 gene were also detected. In conclusion, our study revealed that five of the twelve cases carry at least one mutation of TCIRG1 gene. Further studies with more patients and other genes would help better understanding of genetic etiology of the disease.
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25
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Cao W, Wei W, Wu Q. Ophthalmic phenotype of TCIRG1 gene mutations in Chinese infantile malignant osteopetrosis. BMJ Open Ophthalmol 2018; 3:e000180. [PMID: 30539151 PMCID: PMC6257380 DOI: 10.1136/bmjophth-2018-000180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/17/2022] Open
Abstract
Objective To evaluate the ophthalmic phenotypes associated with T-cell immune regulator 1 (TCIRG1) mutations in Chinese patients with infantile malignant osteopetrosis (IMO). Methods and analysis 27 Chinese TCIRG1-related osteoporosis infants were enrolled using direct DNA sequencing of PCR-amplified exons. 12 cases had frameshift mutation (the frameshift mutation group, group F), and 15 cases had point mutation (the point mutation group, group P). The clinical features of the two groups were compared, including age at onset, gaze qualities, optic atrophy, optic canal stenosis and waveforms of Flash visual-evoked potential (FVEP). Results The clinical signs, except age at onset and FVEP, showed statistically significant differences between the two groups. The mean age at onset was 1.8 months in group F and 4.3 months in group P; 22 eyes (92%) with frameshift mutation and 16 (53%) with point mutation had poor gaze qualities, such as nystagmus and/or strabismus; optic atrophy was found in 16 eyes (67%) in group F and 6 (20%) in group P; the average optic canal diameter was 1.45 mm in the frameshift mutation cases, 1.87 mm in other cases; FVEP indicated that the waveforms in 10 eyes (42%) were not elicited in group F, yet five eyes (17%) in group P. Conclusion In Chinese TCIRG1-related patients of IMO, the optic canal stenosis and optic atrophy were more serious in cases with frameshift mutations. However, no differences in the conduction block of optic nerve were found between the two groups.
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Affiliation(s)
- Wenhong Cao
- Department of Ophthalmology, Beijing Children's Hospital, National Center for Children's Health, National Key Discipline of Pediatrics, Capital Medical University, Beijing, China.,Beijing Tongren Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Science, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Wenbin Wei
- Beijing Tongren Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Science, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Qian Wu
- Department of Ophthalmology, Beijing Children's Hospital, National Center for Children's Health, National Key Discipline of Pediatrics, Capital Medical University, Beijing, China
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26
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Duan X, Yang S, Zhang L, Yang T. V-ATPases and osteoclasts: ambiguous future of V-ATPases inhibitors in osteoporosis. Theranostics 2018; 8:5379-5399. [PMID: 30555553 PMCID: PMC6276090 DOI: 10.7150/thno.28391] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
Vacuolar ATPases (V-ATPases) play a critical role in regulating extracellular acidification of osteoclasts and bone resorption. The deficiencies of subunit a3 and d2 of V-ATPases result in increased bone density in humans and mice. One of the traditional drug design strategies in treating osteoporosis is the use of subunit a3 inhibitor. Recent findings connect subunits H and G1 with decreased bone density. Given the controversial effects of ATPase subunits on bone density, there is a critical need to review the subunits of V-ATPase in osteoclasts and their functions in regulating osteoclasts and bone remodeling. In this review, we comprehensively address the following areas: information about all V-ATPase subunits and their isoforms; summary of V-ATPase subunits associated with human genetic diseases; V-ATPase subunits and osteopetrosis/osteoporosis; screening of all V-ATPase subunits variants in GEFOS data and in-house data; spectrum of V-ATPase subunits during osteoclastogenesis; direct and indirect roles of subunits of V-ATPases in osteoclasts; V-ATPase-associated signaling pathways in osteoclasts; interactions among V-ATPase subunits in osteoclasts; osteoclast-specific V-ATPase inhibitors; perspective of future inhibitors or activators targeting V-ATPase subunits in the treatment of osteoporosis.
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Affiliation(s)
- Xiaohong Duan
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral Biology, Clinic of Oral Rare and Genetic Diseases, School of Stomatology, the Fourth Military Medical University, 145 West Changle Road, Xi'an 710032, P. R. China
| | - Shaoqing Yang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral Biology, Clinic of Oral Rare and Genetic Diseases, School of Stomatology, the Fourth Military Medical University, 145 West Changle Road, Xi'an 710032, P. R. China
| | - Lei Zhang
- Center for Genetic Epidemiology and Genomics, School of Public Health, Medical College of Soochow University, 199 Renai Road, Suzhou, Jiangsu, P. R. China
| | - Tielin Yang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, 28 West Xianning Road, Xi'an 710049, People's Republic of China
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27
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Roh SH, Stam NJ, Hryc CF, Couoh-Cardel S, Pintilie G, Chiu W, Wilkens S. The 3.5-Å CryoEM Structure of Nanodisc-Reconstituted Yeast Vacuolar ATPase V o Proton Channel. Mol Cell 2018. [PMID: 29526695 DOI: 10.1016/j.molcel.2018.02.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The molecular mechanism of transmembrane proton translocation in rotary motor ATPases is not fully understood. Here, we report the 3.5-Å resolution cryoEM structure of the lipid nanodisc-reconstituted Vo proton channel of the yeast vacuolar H+-ATPase, captured in a physiologically relevant, autoinhibited state. The resulting atomic model provides structural detail for the amino acids that constitute the proton pathway at the interface of the proteolipid ring and subunit a. Based on the structure and previous mutagenesis studies, we propose the chemical basis of transmembrane proton transport. Moreover, we discovered that the C terminus of the assembly factor Voa1 is an integral component of mature Vo. Voa1's C-terminal transmembrane α helix is bound inside the proteolipid ring, where it contributes to the stability of the complex. Our structure rationalizes possible mechanisms by which mutations in human Vo can result in disease phenotypes and may thus provide new avenues for therapeutic interventions.
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Affiliation(s)
- Soung-Hun Roh
- Department of Bioengineering and James H. Clark Center, Stanford University, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Nicholas J Stam
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Corey F Hryc
- Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sergio Couoh-Cardel
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Grigore Pintilie
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wah Chiu
- Department of Bioengineering and James H. Clark Center, Stanford University, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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Abstract
PURPOSE OF REVIEW The term osteopetrosis refers to a group of rare skeletal diseases sharing the hallmark of a generalized increase in bone density owing to a defect in bone resorption. Osteopetrosis is clinically and genetically heterogeneous, and a precise molecular classification is relevant for prognosis and treatment. Here, we review recent data on the pathogenesis of this disorder. RECENT FINDINGS Novel mutations in known genes as well as defects in new genes have been recently reported, further expanding the spectrum of molecular defects leading to osteopetrosis. Exploitation of next-generation sequencing tools is ever spreading, facilitating differential diagnosis. Some complex phenotypes in which osteopetrosis is accompanied by additional clinical features have received a molecular classification, also involving new genes. Moreover, novel types of mutations have been recognized, which for their nature or genomic location are at high risk being neglected. Yet, the causative mutation is unknown in some patients, indicating that the genetics of osteopetrosis still deserves intense research efforts.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Milan Unit, CNR-IRGB, Milan, Italy
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy.
- Milan Unit, CNR-IRGB, Milan, Italy.
| | - Anna Villa
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Milan Unit, CNR-IRGB, Milan, Italy
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29
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Ahmadpour A, Goodarzi A, Lee DJ, Panchal RR, Kim KD. Cervical spine fractures in osteopetrosis: a case report and review of the literature. J Biomed Res 2018; 32:68-76. [PMID: 29353820 PMCID: PMC5956260 DOI: 10.7555/jbr.32.20170055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
While management of appendicular fractures has been well described in the setting of osteopetrosis, there is limited information on managing fractures of the axial spine. Here we present an osteopetrotic patient with multiple traumatic multiple, comminuted, unstable cervical spinal fractures managed with non-operative stabilization, and provide a review of the pathophysiology, genetic characteristics, and special considerations that must be explored when determining operative versus non-operative management of spinal injury in osteopetrosis. A PubMed query was performed for English articles in the literature published up to June 2016, and used the following search terms alone and in combination: "osteopetrosis", "spine", "fractures", "osteoclasts", and "operative management". Within four months after initial injury, treatment with halo vest allowed for adequate healing. The patient was asymptomatic with cervical spine dynamic radiographs confirming stability at four months. On four-year follow up examination, the patient remained without neck pain, and CT scan demonstrated partially sclerotic fracture lines with appropriate anatomical alignment. In conclusion, external halo stabilization may be an effective option for treatment of multiple unstable acute traumatic cervical spine fractures in patients with osteopetrosis. Given the challenge of surgical stabilization in osteopetrosis, further research is necessary to elucidate the optimal form of treatment in this select patient population.
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Affiliation(s)
- Arjang Ahmadpour
- Department of Neurological Surgery, University of California-Davis Medical Center, Sacramento, CA 95817, USA
| | - Amir Goodarzi
- Department of Neurological Surgery, University of California-Davis Medical Center, Sacramento, CA 95817, USA
| | - Darrin J Lee
- Department of Neurological Surgery, University of California-Davis Medical Center, Sacramento, CA 95817, USA
| | - Ripul R Panchal
- Department of Neurological Surgery, University of California-Davis Medical Center, Sacramento, CA 95817, USA
| | - Kee D Kim
- Department of Neurological Surgery, University of California-Davis Medical Center, Sacramento, CA 95817, USA
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30
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Zhang XY, He JW, Fu WZ, Wang C, Zhang ZL. Novel mutations of TCIRG1 cause a malignant and mild phenotype of autosomal recessive osteopetrosis (ARO) in four Chinese families. Acta Pharmacol Sin 2017; 38:1456-1465. [PMID: 28816234 DOI: 10.1038/aps.2017.108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/11/2017] [Indexed: 01/04/2023] Open
Abstract
Human autosomal recessive osteopetrosis (ARO), also known as infantile malignant osteopetrosis, is a rare genetic bone disorder that often causes death. Mutations in T-cell immune regulator 1 (TCIRG1) are a frequent cause of human ARO. Six additional genes (TNFSF11, TNFRSF11A, CLCN7, OSTM1, SNX10, PLEKHM1) were also found to be associated with human ARO. In order to expand the mutation spectrum and clinical diversity for a better understanding of the ARO phenotype and to further investigate the clinical characteristics of benign subjects with ARO, we here report five individuals with ARO from four unrelated Chinese families. X-ray examination was conducted and bone turnover markers were assayed. The gene of T-cell immune regulator 1 (TCIRG1) was screened and analyzed. Monocyte-induced osteoclasts were prepared and their resorption ability was studied in vitro. We identified five novel mutations (c.66delC, c.1020+1_1020+5dup, c.2181C>A, c.2236+6T>G, c.692delA) in these patients. Four patients displayed a malignant phenotype, three of them died, and one who received bone marrow transplantation survived. The remaining one, a 24-year-old male from a consanguineous family, was diagnosed based on radiological findings but presented no neurological or hematological defects. He was homozygous for c.2236+6T>G in intron 18; this mutation influenced the splicing process. An in vitro functional study of this novel splicing defect showed no resorption pits on dentine slices. TCIRG1-dependent osteopetrosis with a mild clinical course was observed for the first time in Chinese population. The present findings add to the wide range of phenotypes of Chinese patients with TCIRG1-dependent ARO and enrich the database of TCIRG1 mutations.
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31
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Stattin EL, Henning P, Klar J, McDermott E, Stecksen-Blicks C, Sandström PE, Kellgren TG, Rydén P, Hallmans G, Lönnerholm T, Ameur A, Helfrich MH, Coxon FP, Dahl N, Wikström J, Lerner UH. SNX10 gene mutation leading to osteopetrosis with dysfunctional osteoclasts. Sci Rep 2017; 7:3012. [PMID: 28592808 PMCID: PMC5462793 DOI: 10.1038/s41598-017-02533-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 04/12/2017] [Indexed: 12/21/2022] Open
Abstract
Autosomal recessive osteopetrosis (ARO) is a heterogeneous disorder, characterized by defective osteoclastic resorption of bone that results in increased bone density. We have studied nine individuals with an intermediate form of ARO, from the county of Västerbotten in Northern Sweden. All afflicted individuals had an onset in early infancy with optic atrophy, and in four patients anemia was present at diagnosis. Tonsillar herniation, foramen magnum stenosis, and severe osteomyelitis of the jaw were common clinical features. Whole exome sequencing, verified by Sanger sequencing, identified a splice site mutation c.212 + 1 G > T in the SNX10 gene encoding sorting nexin 10. Sequence analysis of the SNX10 transcript in patients revealed activation of a cryptic splice site in intron 4 resulting in a frame shift and a premature stop (p.S66Nfs * 15). Haplotype analysis showed that all cases originated from a single mutational event, and the age of the mutation was estimated to be approximately 950 years. Functional analysis of osteoclast progenitors isolated from peripheral blood of patients revealed that stimulation with receptor activator of nuclear factor kappa-B ligand (RANKL) resulted in a robust formation of large, multinucleated osteoclasts which generated sealing zones; however these osteoclasts exhibited defective ruffled borders and were unable to resorb bone in vitro.
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Affiliation(s)
- Eva-Lena Stattin
- Department of Medical Biosciences, Medical and Clinical Genetics, Umeå University, 901 87, Umeå, Sweden. .,Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden.
| | - Petra Henning
- Centre for Bone and Arthritis Research, Department of internal medicine and clinical nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30, Gothenburg, Sweden.
| | - Joakim Klar
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Emma McDermott
- Arthritis and Musculoskeletal Medicine Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Christina Stecksen-Blicks
- Pediatric Dentistry, Department of Odontology, Faculty of Medicine, Umeå University, 901 87, Umeå, Sweden
| | | | - Therese G Kellgren
- Department of Mathematics and Mathematical Statistics, Computational Life science Cluster (CLiC), Umeå University, 901 87, Umeå, Sweden
| | - Patrik Rydén
- Department of Mathematics and Mathematical Statistics, Computational Life science Cluster (CLiC), Umeå University, 901 87, Umeå, Sweden
| | - Göran Hallmans
- Department of Biobank Research, Umeå University, 901 87, Umeå, Sweden
| | - Torsten Lönnerholm
- Department of Surgical Sciences, Radiology, Uppsala University, 751 85, Uppsala, Sweden
| | - Adam Ameur
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Miep H Helfrich
- Arthritis and Musculoskeletal Medicine Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Fraser P Coxon
- Arthritis and Musculoskeletal Medicine Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Niklas Dahl
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Johan Wikström
- Department of Surgical Sciences, Radiology, Uppsala University, 751 85, Uppsala, Sweden
| | - Ulf H Lerner
- Centre for Bone and Arthritis Research, Department of internal medicine and clinical nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30, Gothenburg, Sweden.,Molecular Periodontology, Department of Odontology, Faculty of Medicine, Umeå University, 901 87, Umeå, Sweden
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32
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Palagano E, Slatter MA, Uva P, Menale C, Villa A, Abinun M, Sobacchi C. Hematopoietic stem cell transplantation corrects osteopetrosis in a child carrying a novel homozygous mutation in the FERMT3 gene. Bone 2017; 97:126-129. [PMID: 28095295 DOI: 10.1016/j.bone.2017.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/22/2016] [Accepted: 01/13/2017] [Indexed: 12/14/2022]
Abstract
Osteopetrosis (OPT) is a rare skeletal disorder with phenotypic and genotypic heterogeneity: a variety of clinical features besides the bony defect may be present, and at least ten different genes are known to be involved in the disease pathogenesis. In the framework of this heterogeneity, we report the clinical description of a neonate, first child of consanguineous parents, who had osteoclast-rich osteopetrosis and bone marrow failure in early life, but no other usual classical features of infantile malignant OPT, such as visual or hearing impairments. Because of the severe presentation at birth, the patient received Hematopoietic Stem Cell Transplantation (HSCT) at 2months of age with successful outcome. Post-HSCT genetic investigation by means of exome sequencing identified a novel homozygous mutation in the Fermitin Family Member 3 (FERMT3) gene, which was predicted to disrupt the functionality of its protein product kindlin 3. Our report provides information relevant to physicians for recognizing patients with one of the rarest forms of infantile malignant OPT, and clearly demonstrates that HSCT cures kindlin 3 deficiency with severe phenotype.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, Rozzano, Italy; Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Mary A Slatter
- Bone Marrow Transplantation Unit, Great North Children's Hospital, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Primary Immunodeficiency Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Pula, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, Rozzano, Italy; CNR-IRGB, Milan Unit, Milan, Italy
| | - Anna Villa
- Humanitas Clinical and Research Institute, Rozzano, Italy; CNR-IRGB, Milan Unit, Milan, Italy
| | - Mario Abinun
- Bone Marrow Transplantation Unit, Great North Children's Hospital, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Primary Immunodeficiency Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, Rozzano, Italy; CNR-IRGB, Milan Unit, Milan, Italy
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33
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Palagano E, Susani L, Menale C, Ramenghi U, Berger M, Uva P, Oppo M, Vezzoni P, Villa A, Sobacchi C. Synonymous Mutations Add a Layer of Complexity in the Diagnosis of Human Osteopetrosis. J Bone Miner Res 2017; 32:99-105. [PMID: 27468155 DOI: 10.1002/jbmr.2929] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 11/08/2022]
Abstract
Autosomal recessive osteopetroses (AROs) are rare, genetically heterogeneous skeletal diseases with increased bone density that are often lethal if left untreated. A precise molecular classification is relevant for the patient's management, because in some subgroups hematopoietic stem cell transplantation (HSCT), which is the only curative therapy, is contraindicated. In two unrelated ARO patients, the molecular analysis revealed the presence of a synonymous variant in known ARO genes, namely in the TCIRG1 gene in one patient and in the CLCN7 in the other patient, predicted to impact on the splicing process. In the latter case, sequencing of the transcript confirmed the splicing defect, whereas in the former, for whom an RNA sample was not available, the defect was reconstructed in vitro by the minigene technology. These results strongly suggest that these synonymous changes were responsible for the disease in our patients. Our findings are novel with respect to ARO and add to the few reports in literature dealing with different diseases, underlining the importance of cDNA analysis for the correct assessment of exonic changes, even when exome sequencing is performed. In particular, we highlight the possibility that at least in some cases ARO is due to synonymous changes, erroneously considered clinically silent, in the genes already described in literature, and suggest carefully reevaluating the sequencing results of these genes when mutations are not found at a first analysis. In addition, with respect to the CLCN7 gene, we suggest that synonymous variants might also contribute to the large spectrum of severity typical of CLCN7-dependent osteopetrosis through more subtle, but not negligible, effects on protein availability and functionality. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, Rozzano, Italy.,Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Lucia Susani
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Ugo Ramenghi
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Massimo Berger
- Pediatric Onco-Hematology and Stem Cell Transplant Division, Regina Margherita Children Hospital, City of Health and Science, Turin, Italy
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Pula, Italy
| | - Manuela Oppo
- CRS4, Science and Technology Park Polaris, Pula, Italy.,Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Paolo Vezzoni
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Anna Villa
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
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34
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Colacurcio DJ, Nixon RA. Disorders of lysosomal acidification-The emerging role of v-ATPase in aging and neurodegenerative disease. Ageing Res Rev 2016; 32:75-88. [PMID: 27197071 DOI: 10.1016/j.arr.2016.05.004] [Citation(s) in RCA: 299] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/02/2016] [Accepted: 05/13/2016] [Indexed: 12/21/2022]
Abstract
Autophagy and endocytosis deliver unneeded cellular materials to lysosomes for degradation. Beyond processing cellular waste, lysosomes release metabolites and ions that serve signaling and nutrient sensing roles, linking the functions of the lysosome to various pathways for intracellular metabolism and nutrient homeostasis. Each of these lysosomal behaviors is influenced by the intraluminal pH of the lysosome, which is maintained in the low acidic range by a proton pump, the vacuolar ATPase (v-ATPase). New reports implicate altered v-ATPase activity and lysosomal pH dysregulation in cellular aging, longevity, and adult-onset neurodegenerative diseases, including forms of Parkinson disease and Alzheimer disease. Genetic defects of subunits composing the v-ATPase or v-ATPase-related proteins occur in an increasingly recognized group of familial neurodegenerative diseases. Here, we review the expanding roles of the v-ATPase complex as a platform regulating lysosomal hydrolysis and cellular homeostasis. We discuss the unique vulnerability of neurons to persistent low level lysosomal dysfunction and review recent clinical and experimental studies that link dysfunction of the v-ATPase complex to neurodegenerative diseases across the age spectrum.
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35
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How rare bone diseases have informed our knowledge of complex diseases. BONEKEY REPORTS 2016; 5:839. [PMID: 27688878 DOI: 10.1038/bonekey.2016.69] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/22/2016] [Indexed: 02/07/2023]
Abstract
Rare bone diseases, generally defined as monogenic traits with either autosomal recessive or dominant patterns of inheritance, have provided a rich database of genes and associated pathways over the past 2-3 decades. The molecular genetic dissection of these bone diseases has yielded some major surprises in terms of the causal genes and/or involved pathways. The discovery of genes/pathways involved in diseases such as osteopetrosis, osteosclerosis, osteogenesis imperfecta and many other rare bone diseases have all accelerated our understanding of complex traits. Importantly these discoveries have provided either direct validation for a specific gene embedded in a group of genes within an interval identified through a complex trait genome-wide association study (GWAS) or based upon the pathway associated with a monogenic trait gene, provided a means to prioritize a large number of genes for functional validation studies. In some instances GWAS studies have yielded candidate genes that fall within linkage intervals associated with monogenic traits and resulted in the identification of causal mutations in those rare diseases. Driving all of this discovery is a complement of technologies such as genome sequencing, bioinformatics and advanced statistical analysis methods that have accelerated genetic dissection and greatly reduced the cost. Thus, rare bone disorders in partnership with GWAS have brought us to the brink of a new era of personalized genomic medicine in which the prevention and management of complex diseases will be driven by the molecular understanding of each individuals contributing genetic risks for disease.
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36
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Duan X, Liu J, Zheng X, Wang Z, Zhang Y, Hao Y, Yang T, Deng H. Deficiency of ATP6V1H Causes Bone Loss by Inhibiting Bone Resorption and Bone Formation through the TGF-β1 Pathway. Am J Cancer Res 2016; 6:2183-2195. [PMID: 27924156 PMCID: PMC5135442 DOI: 10.7150/thno.17140] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/15/2016] [Indexed: 12/02/2022] Open
Abstract
Vacuolar-type H +-ATPase (V-ATPase) is a highly conserved, ancient enzyme that couples the energy of ATP hydrolysis to proton transport across vesicular and plasma membranes of eukaryotic cells. Previously reported mutations of various V-ATPase subunits are associated with increased bone density. We now show that haploinsufficiency for the H subunit of the V1 domain (ATP6V1H) is associated with osteoporosis in humans and mice. A genome-wide SNP array analysis of 1625 Han Chinese found that 4 of 15 tag SNPs (26.7%) within ATP6V1H were significantly associated with low spine bone mineral density. Atp6v1h+/- knockout mice generated by the CRISPR/Cas9 technique had decreased bone remodeling and a net bone matrix loss. Atp6v1h+/- osteoclasts showed impaired bone formation and increased bone resorption. The increased intracellular pH of Atp6v1h+/- osteoclasts downregulated TGF-β1 activation, thereby reducing induction of osteoblast formation but the bone mineralization was not altered. However, bone formation was reduced more than bone resorption. Our data provide evidence that partial loss of ATP6V1H function results in osteoporosis/osteopenia. We propose that defective osteoclast formation triggers impaired bone formation by altering bone remodeling. In the future, ATP6V1H might, therefore, serve as a target for the therapy of osteoporosis.
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37
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Zhu S, Rea SL, Cheng T, Feng HT, Walsh JP, Ratajczak T, Tickner J, Pavlos N, Xu HZ, Xu J. Bafilomycin A1 Attenuates Osteoclast Acidification and Formation, Accompanied by Increased Levels of SQSTM1/p62 Protein. J Cell Biochem 2015; 117:1464-70. [PMID: 27043248 DOI: 10.1002/jcb.25442] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 11/11/2015] [Indexed: 12/14/2022]
Abstract
Vacuolar proton pump H(+)-adenosine triphosphatases (V-ATPases) play an important role in osteoclast function. Further understanding of the cellular and molecular mechanisms of V-ATPase inhibition is vital for the development of anti-resorptive drugs specifically targeting osteoclast V-ATPases. In this study, we observed that bafilomycin A1, a naturally-occurring inhibitor of V-ATPases, increased the protein level of SQSTM1/p62, a known negative regulator of osteoclast formation. Consistently, we found that bafilomycin A1 diminishes the intracellular accumulation of the acidotropic probe lysotracker in osteoclast-like cells; indicative of reduced acidification. Further, bafilomycin A1 inhibits osteoclast formation with attenuation of cell fusion and multi-nucleation of osteoclast-like cells during osteoclast differentiation. Taken together, these data indicate that bafilomycin A1 attenuates osteoclast differentiation in part via increased levels of SQSTM1/p62 protein, providing further mechanistic insight into the effect of V-ATPase inhibition in osteoclasts.
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Affiliation(s)
- Sipin Zhu
- Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China.,School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
| | - Sarah L Rea
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and UWA Centre for Medical Research, The University of Western Australia, Crawley, WA, 6009, Australia.,Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia
| | - Taksum Cheng
- School of Surgery, Centre of Orthopaedic Research, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Hao Tian Feng
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
| | - John P Walsh
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Thomas Ratajczak
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and UWA Centre for Medical Research, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Jennifer Tickner
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
| | - Nathan Pavlos
- School of Surgery, Centre of Orthopaedic Research, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Hua-Zi Xu
- Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Jiake Xu
- Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China.,School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
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38
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Berndt A, Ackert-Bicknell C, Silva KA, Kennedy VE, Sundberg BA, Cates JM, Schofield PN, Sundberg JP. Genetic determinants of fibro-osseous lesions in aged inbred mice. Exp Mol Pathol 2015; 100:92-100. [PMID: 26589134 DOI: 10.1016/j.yexmp.2015.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 11/12/2015] [Indexed: 12/12/2022]
Abstract
Fibro-osseous lesions in mice are progressive aging changes in which the bone marrow is replaced to various degrees by fibrovascular stroma and bony trabeculae in a wide variety of bones. The frequency and severity varied greatly among 28 different inbred mouse stains, predominantly affecting females, ranging from 0% for 10 strains to 100% for KK/HlJ and NZW/LacJ female mice. Few lesions were observed in male mice and for 23 of the strains, no lesions were observed in males for any of the cohorts. There were no significant correlations between strain-specific severities of fibro-osseous lesions and ovarian (r=0.11; P=0.57) or endometrial (r=0.03; P=0.89) cyst formation frequency or abnormalities in parathyroid glands. Frequency of fibro-osseous lesions was most strongly associated (P<10(-6)) with genome variations on chromosome (Chr) 8 at 90.6 and 90.8Mb (rs33108071, rs33500669; P=5.0·10(-10), 1.3·10(-6)), Chr 15 at 23.6 and 23.8Mb (rs32087871, rs45770368; P=7.3·10(-7), 2.7·10(-6)), and Chr 19 at 33.2, 33.4, and 33.6Mb (rs311004232, rs30524929, rs30448815; P=2.8·10(-6), 2.8·10(-6), 2.8·10(-6)) in genome-wide association studies (GWAS). The relatively large number of candidate genes identified in the GWAS analyses suggests that this may be an extremely complex polygenic disease. These results indicate that fibro-osseous lesions are surprisingly common in many inbred strains of laboratory mice as they age. While this presents little problem in most studies that utilize young animals, it may complicate aging studies, particularly those focused on bone.
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Affiliation(s)
- Annerose Berndt
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
| | | | | | | | | | - Justin M Cates
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, United States.
| | - Paul N Schofield
- The Jackson Laboratory, Bar Harbor, ME, United States; Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.
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39
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V-type ATPase proton pump expression during enamel formation. Matrix Biol 2015; 52-54:234-245. [PMID: 26586472 DOI: 10.1016/j.matbio.2015.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 10/29/2015] [Accepted: 11/09/2015] [Indexed: 01/12/2023]
Abstract
Several diseases such as proximal and distal renal tubular acidosis and osteoporosis are related to intracellular pH dysregulation resulting from mutations in genes coding for ion channels, including proteins comprising the proton-pumping V-type ATPase. V-type ATPase is a multi-subunit protein complex expressed in enamel forming cells. V-type ATPase plays a key role in enamel development, specifically lysosomal acidification, yet our understanding of the relationship between the endocytotic activities and dental health and disease is limited. The objective of this study is to better understand the ameloblast-associated pH regulatory networks essential for amelogenesis. Quantitative RT-PCR was performed on tissues from secretory-stage and maturation-stage enamel organs to determine which of the V-type ATPase subunits are most highly upregulated during maturation-stage amelogenesis: a time when ameloblast endocytotic activity is highest. Western blot analyses, using specific antibodies to four of the V-type ATPase subunits (Atp6v0d2, Atp6v1b2, Atp6v1c1 and Atp6v1e1), were then applied to validate much of the qPCR data. Immunohistochemistry using these same four antibodies was also performed to identify the spatiotemporal expression profiles of individual V-type ATPase subunits. Our data show that cytoplasmic V-type ATPase is significantly upregulated in enamel organ cells during maturation-stage when compared to secretory-stage. These data likely relate to the higher endocytotic activities, and the greater need for lysosomal acidification, during maturation-stage amelogenesis. It is also apparent from our immunolocalization data, using antibodies against two of the V-type ATPase subunits (Atp6v1c1 and Atp6v1e1), that significant expression is seen at the apical membrane of maturation-stage ameloblasts. Others have also identified this V-type ATPase expression profile at the apical membrane of maturation ameloblasts. Collectively, these data better define the expression and role of the V-type ATPase proton pump in the enamel organ during amelogenesis.
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40
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Palagano E, Blair HC, Pangrazio A, Tourkova I, Strina D, Angius A, Cuccuru G, Oppo M, Uva P, Van Hul W, Boudin E, Superti-Furga A, Faletra F, Nocerino A, Ferrari MC, Grappiolo G, Monari M, Montanelli A, Vezzoni P, Villa A, Sobacchi C. Buried in the Middle but Guilty: Intronic Mutations in the TCIRG1 Gene Cause Human Autosomal Recessive Osteopetrosis. J Bone Miner Res 2015; 30:1814-21. [PMID: 25829125 DOI: 10.1002/jbmr.2517] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 03/16/2015] [Accepted: 03/22/2015] [Indexed: 11/10/2022]
Abstract
Autosomal recessive osteopetrosis (ARO) is a rare genetic bone disease with genotypic and phenotypic heterogeneity, sometimes translating into delayed diagnosis and treatment. In particular, cases of intermediate severity often constitute a diagnostic challenge and represent good candidates for exome sequencing. Here, we describe the tortuous path to identification of the molecular defect in two siblings, in which osteopetrosis diagnosed in early childhood followed a milder course, allowing them to reach the adult age in relatively good conditions with no specific therapy. No clearly pathogenic mutation was identified either with standard amplification and resequencing protocols or with exome sequencing analysis. While evaluating the possible impact of a 3'UTR variant on the TCIRG1 expression, we found a novel single nucleotide change buried in the middle of intron 15 of the TCIRG1 gene, about 150 nucleotides away from the closest canonical splice site. By sequencing a number of independent cDNA clones covering exons 14 to 17, we demonstrated that this mutation reduced splicing efficiency but did not completely abrogate the production of the normal transcript. Prompted by this finding, we sequenced the same genomic region in 33 patients from our unresolved ARO cohort and found three additional novel single nucleotide changes in a similar location and with a predicted disruptive effect on splicing, further confirmed in one of them at the transcript level. Overall, we identified an intronic region in TCIRG1 that seems to be particularly prone to splicing mutations, allowing the production of a small amount of protein sufficient to reduce the severity of the phenotype usually associated with TCIRG1 defects. On this basis, we would recommend including TCIRG1 not only in the molecular work-up of severe infantile osteopetrosis but also in intermediate cases and carefully evaluating the possible effects of intronic changes.
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Affiliation(s)
- Eleonora Palagano
- UOS/IRGB, Milan Unit, National Research Council (CNR), Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
| | - Harry C Blair
- Veteran's Affairs Medical Center and Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alessandra Pangrazio
- UOS/IRGB, Milan Unit, National Research Council (CNR), Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
| | - Irina Tourkova
- Veteran's Affairs Medical Center and Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dario Strina
- UOS/IRGB, Milan Unit, National Research Council (CNR), Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
| | - Andrea Angius
- CRS4, Science and Technology Park Polaris, Piscina Manna, Pula, Italy.,Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Monserrato, Italy
| | - Gianmauro Cuccuru
- CRS4, Science and Technology Park Polaris, Piscina Manna, Pula, Italy
| | - Manuela Oppo
- CRS4, Science and Technology Park Polaris, Piscina Manna, Pula, Italy
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Piscina Manna, Pula, Italy
| | - Wim Van Hul
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Eveline Boudin
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Andrea Superti-Furga
- Department of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Flavio Faletra
- Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
| | - Agostino Nocerino
- Clinica Pediatrica, Azienda Ospedaliero-Universitaria "S Maria della Misericordia", Udine, Italy
| | - Matteo C Ferrari
- Hip and Prosthetic Replacement Unit, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Guido Grappiolo
- Hip and Prosthetic Replacement Unit, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Marta Monari
- Clinical Investigation Laboratory, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Alessandro Montanelli
- Clinical Investigation Laboratory, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Paolo Vezzoni
- UOS/IRGB, Milan Unit, National Research Council (CNR), Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
| | - Anna Villa
- UOS/IRGB, Milan Unit, National Research Council (CNR), Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
| | - Cristina Sobacchi
- UOS/IRGB, Milan Unit, National Research Council (CNR), Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
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41
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Coudert AE, de Vernejoul MC, Muraca M, Del Fattore A. Osteopetrosis and its relevance for the discovery of new functions associated with the skeleton. Int J Endocrinol 2015; 2015:372156. [PMID: 25873953 PMCID: PMC4385565 DOI: 10.1155/2015/372156] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/16/2014] [Accepted: 10/30/2014] [Indexed: 01/29/2023] Open
Abstract
Osteopetrosis is a rare genetic disorder characterized by an increase of bone mass due to defective osteoclast function. Patients typically displayed spontaneous fractures, anemia, and in the most severe forms hepatosplenomegaly and compression of cranial facial nerves leading to deafness and blindness. Osteopetrosis comprises a heterogeneous group of diseases as several forms are known with different models of inheritance and severity from asymptomatic to lethal. This review summarizes the genetic and clinical features of osteopetrosis, emphasizing how recent studies of this disease have contributed to understanding the central role of the skeleton in the whole body physiology. In particular, the interplay of bone with the stomach, insulin metabolism, male fertility, the immune system, bone marrow, and fat is described.
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Affiliation(s)
- Amélie E. Coudert
- Institut National de la Santé et de la Recherche Médicale U1138, Centre de Recherche des Cordeliers, Paris, France
| | | | - Maurizio Muraca
- Regenerative Medicine Unit, Bambino Gesù Children's Hospital, IRCCS, Piazza Sant'Onofrio 4, 00165 Rome, Italy
| | - Andrea Del Fattore
- Regenerative Medicine Unit, Bambino Gesù Children's Hospital, IRCCS, Piazza Sant'Onofrio 4, 00165 Rome, Italy
- *Andrea Del Fattore:
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42
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Siddaiahgari SR, Makadia D, Shah N, Devi RR, Lingappa L. Identification of novel mutation in autosomal recessive infantile malignant osteopetrosis. Indian J Pediatr 2014; 81:969-70. [PMID: 24101165 DOI: 10.1007/s12098-013-1250-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 09/11/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Sirisha Rani Siddaiahgari
- Division of Pediatric Hematology Oncology, Rainbow Children's Hospital and Perinatal Centre, Hyderabad, 500034, India,
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43
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Anderson SL, Jalas C, Fedick A, Reid KF, Carpenter TO, Chirnomas D, Treff NR, Ekstein J, Rubin BY. A founder mutation in the TCIRG1 gene causes osteopetrosis in the Ashkenazi Jewish population. Clin Genet 2014; 88:74-9. [PMID: 24989235 DOI: 10.1111/cge.12448] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 06/11/2014] [Accepted: 06/19/2014] [Indexed: 12/27/2022]
Abstract
Osteopetrosis is a rare and heterogeneous genetic disorder characterized by dense bone mass that is a consequence of defective osteoclast function and/or development. Autosomal recessive osteopetrosis (ARO) is the most severe form and is often fatal within the first years of life; early hematopoietic stem cell transplant (HSCT) remains the only curative treatment for ARO. The majority of the ARO-causing mutations are located in the TCIRG1 gene. We report here the identification and characterization of an A to T transversion in the fourth base of the intron 2 donor splice site (c.117+4A→T) in TCIRG1, a mutation not previously seen in the Ashkenazi Jewish (AJ) population. Analysis of a random sample of individuals of AJ descent revealed a carrier frequency of approximately 1 in 350. Genotyping of five loci adjacent to the c.117+4A→T-containing TCIRG1 allele revealed that the presence of this mutation in the AJ population is due to a single founder. The identification of this mutation will enable population carrier testing and will facilitate the identification and treatment of individuals homozygous for this mutation.
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Affiliation(s)
- S L Anderson
- Department of Biological Sciences, Fordham University, Bronx, NY, 10458, USA
| | - C Jalas
- Bonei Olam, Center for Rare Jewish Genetic Disorders, Brooklyn, NY, 11204, USA
| | - A Fedick
- Department of Microbiology and Molecular Genetics, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - K F Reid
- Department of Biological Sciences, Fordham University, Bronx, NY, 10458, USA
| | - T O Carpenter
- Yale University School of Medicine, Departments of Pediatrics (Endocrinology) and Orthopedics and Rehabilitation, New Haven, CT, 06520, USA
| | - D Chirnomas
- Yale University School of Medicine, Departments of Pediatrics (Endocrinology) and Orthopedics and Rehabilitation, New Haven, CT, 06520, USA
| | - N R Treff
- Department of Microbiology and Molecular Genetics, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA.,Reproductive Medicine Associates of New Jersey, Department of Research, Morristown, NJ, 07960, USA
| | - J Ekstein
- Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY, 11211, USA
| | - B Y Rubin
- Department of Biological Sciences, Fordham University, Bronx, NY, 10458, USA
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44
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Sobacchi C, Pangrazio A, Lopez AGM, Gomez DPV, Caldana ME, Susani L, Vezzoni P, Villa A. As little as needed: the extraordinary case of a mild recessive osteopetrosis owing to a novel splicing hypomorphic mutation in the TCIRG1 gene. J Bone Miner Res 2014; 29:1646-50. [PMID: 24535816 PMCID: PMC4258090 DOI: 10.1002/jbmr.2203] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/23/2014] [Accepted: 02/09/2014] [Indexed: 01/22/2023]
Abstract
Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50% of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice-site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1 mutations is present neither in our series of more than 100 TCIRG1-dependent ARO patients nor in the literature. Here we describe an 8-year-old patient referred to us with a clinical diagnosis of ARO, based on radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1-dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe ARO phenotype, and this is particularly important when gene therapy approaches are considered. In addition, we would also recommend that the TCIRG1 gene be included in the molecular diagnosis of mild forms of human ARO.
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Affiliation(s)
- Cristina Sobacchi
- Unitá Operativa di Supporto (UOS)/Institute of Genetic and Biomedical Research (IRGB), Milan Unit, National Research Council (CNR), Milan, Italy; Humanitas Clinical and Research Center, Rozzano, Italy
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45
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Chan CY, Parra KJ. Yeast phosphofructokinase-1 subunit Pfk2p is necessary for pH homeostasis and glucose-dependent vacuolar ATPase reassembly. J Biol Chem 2014; 289:19448-57. [PMID: 24860096 DOI: 10.1074/jbc.m114.569855] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
V-ATPases are conserved ATP-driven proton pumps that acidify organelles. Yeast V-ATPase assembly and activity are glucose-dependent. Glucose depletion causes V-ATPase disassembly and its inactivation. Glucose readdition triggers reassembly and resumes proton transport and organelle acidification. We investigated the roles of the yeast phosphofructokinase-1 subunits Pfk1p and Pfk2p for V-ATPase function. The pfk1Δ and pfk2Δ mutants grew on glucose and assembled wild-type levels of V-ATPase pumps at the membrane. Both phosphofructokinase-1 subunits co-immunoprecipitated with V-ATPase in wild-type cells; upon deletion of one subunit, the other subunit retained binding to V-ATPase. The pfk2Δ cells exhibited a partial vma growth phenotype. In vitro ATP hydrolysis and proton transport were reduced by 35% in pfk2Δ membrane fractions; they were normal in pfk1Δ. In vivo, the pfk1Δ and pfk2Δ vacuoles were alkalinized and the cytosol acidified, suggestive of impaired V-ATPase proton transport. Overall the pH alterations were more dramatic in pfk2Δ than pfk1Δ at steady state and after readdition of glucose to glucose-deprived cells. Glucose-dependent reassembly was 50% reduced in pfk2Δ, and the vacuolar lumen was not acidified after reassembly. RAVE-assisted glucose-dependent reassembly and/or glucose signals were disturbed in pfk2Δ. Binding of disassembled V-ATPase (V1 domain) to its assembly factor RAVE (subunit Rav1p) was 5-fold enhanced, indicating that Pfk2p is necessary for V-ATPase regulation by glucose. Because Pfk1p and Pfk2p are necessary for V-ATPase proton transport at the vacuole in vivo, a role for glycolysis at regulating V-ATPase proton transport is discussed.
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Affiliation(s)
- Chun-Yuan Chan
- From the Department of Biochemistry and Molecular Biology of the School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Karlett J Parra
- From the Department of Biochemistry and Molecular Biology of the School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
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Makaryan V, Rosenthal EA, Bolyard AA, Kelley ML, Below JE, Bamshad MJ, Bofferding KM, Smith JD, Buckingham K, Boxer LA, Skokowa J, Welte K, Nickerson DA, Jarvik GP, Dale DC. TCIRG1-associated congenital neutropenia. Hum Mutat 2014; 35:824-7. [PMID: 24753205 DOI: 10.1002/humu.22563] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 03/28/2014] [Indexed: 11/12/2022]
Abstract
Severe congenital neutropenia (SCN) is a rare hematopoietic disorder, with estimated incidence of 1 in 200,000 individuals of European descent, many cases of which are inherited in an autosomal dominant pattern. Despite the fact that several causal genes have been identified, the genetic basis for >30% of cases remains unknown. We report a five-generation family segregating a novel single nucleotide variant (SNV) in TCIRG1. There is perfect cosegregation of the SNV with congenital neutropenia in this family; all 11 affected, but none of the unaffected, individuals carry this novel SNV. Western blot analysis show reduced levels of TCIRG1 protein in affected individuals, compared to healthy controls. Two unrelated patients with SCN, identified by independent investigators, are heterozygous for different, rare, highly conserved, coding variants in TCIRG1.
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Affiliation(s)
- Vahagn Makaryan
- Department of Medicine, Divisions of GIM, University of Washington, Seattle, Washington
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Saccharomyces cerevisiae vacuolar H+-ATPase regulation by disassembly and reassembly: one structure and multiple signals. EUKARYOTIC CELL 2014; 13:706-14. [PMID: 24706019 DOI: 10.1128/ec.00050-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vacuolar H(+)-ATPases (V-ATPases) are highly conserved ATP-driven proton pumps responsible for acidification of intracellular compartments. V-ATPase proton transport energizes secondary transport systems and is essential for lysosomal/vacuolar and endosomal functions. These dynamic molecular motors are composed of multiple subunits regulated in part by reversible disassembly, which reversibly inactivates them. Reversible disassembly is intertwined with glycolysis, the RAS/cyclic AMP (cAMP)/protein kinase A (PKA) pathway, and phosphoinositides, but the mechanisms involved are elusive. The atomic- and pseudo-atomic-resolution structures of the V-ATPases are shedding light on the molecular dynamics that regulate V-ATPase assembly. Although all eukaryotic V-ATPases may be built with an inherent capacity to reversibly disassemble, not all do so. V-ATPase subunit isoforms and their interactions with membrane lipids and a V-ATPase-exclusive chaperone influence V-ATPase assembly. This minireview reports on the mechanisms governing reversible disassembly in the yeast Saccharomyces cerevisiae, keeping in perspective our present understanding of the V-ATPase architecture and its alignment with the cellular processes and signals involved.
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48
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Barvencik F, Kurth I, Koehne T, Stauber T, Zustin J, Tsiakas K, Ludwig CF, Beil FT, Pestka JM, Hahn M, Santer R, Supanchart C, Kornak U, Del Fattore A, Jentsch TJ, Teti A, Schulz A, Schinke T, Amling M. CLCN7 and TCIRG1 mutations differentially affect bone matrix mineralization in osteopetrotic individuals. J Bone Miner Res 2014; 29:982-91. [PMID: 24108692 DOI: 10.1002/jbmr.2100] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 01/10/2023]
Abstract
Osteopetrosis is an inherited disorder of impaired bone resorption, with the most commonly affected genes being CLCN7 and TCIRG1, encoding the Cl(-) /H(+) exchanger CLC-7 and the a3 subunit of the vacuolar H(+) -ATPase, respectively. We and others have previously shown that the disease is frequently accompanied by osteomalacia, and that this additional pathology is also found in Tcirg1-deficient oc/oc mice. The remaining question was whether osteoid enrichment is specifically associated with TCIRG1 inactivation, or whether CLCN7 mutations would also cause skeletal mineralization defects. Here we describe a complete osteologic assessment of one family carrying a novel mutation in CLCN7 (D145G), which impairs the activation and relaxation kinetics of the CLC-7 ion transporter. The two siblings carrying the mutation in the homozygous state displayed high bone mass, increased serum levels of bone formation markers, but no impairment of calcium homeostasis when compared to the other family members. Most importantly, however, undecalcified processing of an iliac crest biopsy from one of the affected children clearly demonstrated a pathological increase of trabecular bone mass, but no signs of osteomalacia. Given the potential relevance of these findings we additionally performed undecalcified histology of iliac crest biopsies from seven additional cases with osteopetrosis caused by a mutation in TNFRSF11A (n=1), CLCN7 (n=3), or TCIRG1 (n=3). Here we observed that all cases with TCIRG1-dependent osteopetrosis displayed severe osteoid accumulation and decreased calcium content within the mineralized matrix. In contrast, there was no detectable bone mineralization defect in the cases with TNFRSF11A-dependent or CLCN7-dependent osteopetrosis. Taken together, our analysis demonstrates that CLCN7 and TCIRG1 mutations differentially affect bone matrix mineralization, and that there is a need to modify the current classification of osteopetrosis.
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Affiliation(s)
- Florian Barvencik
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Yu T, Yu Y, Wang J, Yin L, Zhou Y, Ying D, Huang R, Chen H, Wu S, Shen Y, Fu Q, Chen F. Identification of TCIRG1 and CLCN7 gene mutations in a patient with autosomal recessive osteopetrosis. Mol Med Rep 2014; 9:1191-6. [PMID: 24535484 DOI: 10.3892/mmr.2014.1955] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 02/04/2014] [Indexed: 01/26/2023] Open
Abstract
Osteopetrosis is a heritable bone disorder that exhibits highly clinical and genetical heterogeneity, and is caused by defective osteoclastic resorption. The three main forms are the autosomal recessive severe (ARO), the intermediate autosomal and the autosomal dominant benign osteopetrosis forms. In the present study, the clinical, biochemical and radiological manifestations were described in a patient with osteopetrosis. Sequence analysis identified the compound heterozygous mutations, c.909C>A (p.Tyr303X) and c.2008C>T (p.Arg670X), in TCIRG1, and a heterozygous splicing mutation, c.1798‑1G>T, in the chloride channel 7 gene (CLCN7). Two aberrant forms of the CLCN7 transcripts, c.1798_1883 (exon 20) deletion predicted to cause p.Leu601GlyfsX13, and the c.1798_1821 deletion, the first 24 bp of the exon 20, predicted to cause p.Gly600_Gln607del, were detected by further analysis of the splicing patterns in the leukocytes. The patient's asymptomatic mother carried the TCIRG1 c.909C>A (p.Tyr303X) and CLCN7 c.1798‑1G>T mutations, while the asymptomatic father carried the TCIRG1 c.2008C>T (p.Arg670X) mutation only. The patient was finally diagnosed with ARO on the basis of clinical and biochemical parameters, radiological changes and genetic defects. To the best of our knowledge, this is the first reported case of a patient with osteopetrosis who carries TCIRG1 and CLCN7 mutations. In addition, among the three mutations, TCIRG1 c.909C>A and CLCN7 c.1798‑1G>T were novel mutations.
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Affiliation(s)
- Tingting Yu
- Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
| | - Yongguo Yu
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Jian Wang
- Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Lei Yin
- Department of Internal Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Yunfang Zhou
- Rare Diseases Outpatient Clinic, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Daming Ying
- Rare Diseases Outpatient Clinic, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Rongkui Huang
- Rare Diseases Outpatient Clinic, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Huijin Chen
- Rare Diseases Outpatient Clinic, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Shenmei Wu
- Rare Diseases Outpatient Clinic, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Yongnian Shen
- Department of Internal Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Qihua Fu
- Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Fuxiang Chen
- Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
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Ochotny N, Voronov I, Owen C, Aubin JE, Manolson MF. The R740S mutation in the V-ATPase a3 subunit results in osteoclast apoptosis and defective early-stage autophagy. J Cell Biochem 2013; 114:2823-33. [DOI: 10.1002/jcb.24630] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 07/22/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Noelle Ochotny
- Faculty of Dentistry; Dental Research Institute; University of Toronto; Toronto; Ontario; Canada
| | - Irina Voronov
- Faculty of Dentistry; Dental Research Institute; University of Toronto; Toronto; Ontario; Canada
| | - Celeste Owen
- Centre for Modeling Human Disease; Samuel Lunenfeld Research Institute; Mt. Sinai Hospital; Toronto; Ontario; Canada
| | | | - Morris F. Manolson
- Faculty of Dentistry; Dental Research Institute; University of Toronto; Toronto; Ontario; Canada
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