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Ansh AJ, Stabach PR, Ciccone C, Cao W, De La Cruz EM, Sabbagh Y, Carpenter TO, Ferreira CR, Braddock DT. Quantitative correlation of ENPP1 pathogenic variants with disease phenotype. Bone 2024:117136. [PMID: 38806089 DOI: 10.1016/j.bone.2024.117136] [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: 02/05/2024] [Revised: 04/07/2024] [Accepted: 05/24/2024] [Indexed: 05/30/2024]
Abstract
Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) codes for a type 2 transmembrane glycoprotein which hydrolyzes extracellular phosphoanhydrides into bio-active molecules that regulate, inter alia, ectopic mineralization, bone formation, vascular endothelial proliferation, and the innate immune response. The clinical phenotypes produced by ENPP1 deficiency are disparate, ranging from life-threatening arterial calcifications to cutaneous hypopigmentation. To investigate associations between disease phenotype and enzyme activity we quantified the enzyme velocities of 29 unique ENPP1 pathogenic variants in 41 patients enrolled in an NIH study along with 33 other variants reported in literature. We correlated the relative enzyme velocities with the presenting clinical diagnoses, performing the catalytic velocity measurements simultaneously in triplicate using a high-throughput assay to reduce experimental variation. We found that ENPP1 variants associated with autosomal dominant phenotypes reduced enzyme velocities by 50 % or more, whereas variants associated with insulin resistance had non-significant effects on enzyme velocity. In Cole's disease the catalytic velocities of ENPP1 variants associated with AD forms trended to lower values than those associated with autosomal recessive forms - 8-32 % vs. 33 % of WT, respectively. Additionally, ENPP1 variants leading to life-threatening vascular calcifications in GACI patients had widely variable enzyme activities, ranging from no significant differences compared to WT to the complete abolishment of enzyme velocity. Finally, disease severity in GACI did not correlate with the mean enzyme velocity of the variants present in affected compound heterozygotes but did correlate with the more severely damaging variant. In summary, correlation of ENPP1 enzyme velocity with disease phenotypes demonstrate that enzyme velocities below 50 % of WT levels are likely to occur in the context of autosomal dominant disease (due to a monoallelic variant), and that disease severity in GACI infants correlates with the more severely damaging ENPP1 variant in compound heterozygotes, not the mean velocity of the pathogenic variants present.
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Affiliation(s)
- Anenya Jai Ansh
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Paul R Stabach
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Carla Ciccone
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Yves Sabbagh
- Inozyme Pharma, 321 Summer St., Suite 400, Boston, MA 02201, USA
| | - Thomas O Carpenter
- Department of Pediatrics (Endocrinology), Yale University School of Medicine, New Haven, CT, USA
| | - Carlos R Ferreira
- Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Demetrios T Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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Tourkova IL, Larrouture QC, Liu S, Luo J, Schlesinger PH, Blair HC. The ecto-nucleotide pyrophosphatase/phosphodiesterase 2 promotes early osteoblast differentiation and mineralization in stromal stem cells. Am J Physiol Cell Physiol 2024; 326:C843-C849. [PMID: 38223929 PMCID: PMC11193479 DOI: 10.1152/ajpcell.00692.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
The phosphodiesterase enzymes mediate calcium-phosphate deposition in various tissues, although which enzymes are active in bone mineralization is unclear. Using gene array analysis, we found that a member of ecto-nucleotide pyrophosphatase/phosphodiesterase family, ENPP2, was strongly down-regulated with age in stromal stem cells that produce osteoblasts and make bone. This is in keeping with reduced bone formation in older animals. Thus, we hypothesized that ENPP2 is, at least in part, an early mediator of bone formation and thus may reflect reduced bone formation with age. Since ENPP2 has not previously been shown to have a role in osteoblast differentiation, we studied its effect on bone differentiation from stromal stem cells, verified by flow cytometry for stem cell antigens. In these remarkably uniform osteoblast precursors, we did transfection with ENPP2 DsiRNA, scrambled DsiRNA, or no transfection to make cells with normal or greatly reduced ENPP2 and analyzed osteoblast differentiation and mineralization. Osteoblast differentiation down-regulation was shown by alizarin red binding, silver staining, and alkaline phosphatase activity. Differences were confirmed by real-time PCR for alkaline phosphatase (ALPL), osteocalcin (BGLAP), and ENPP2 and by Western Blot for Enpp2. These were decreased, ∼50%, in osteoblasts transfected with ENPP2 DsiRNA compared with cells transfected with a scrambled DsiRNA or not transfected (control) cells. This finding is the first evidence for the role of ENPP2 in osteoblast differentiation and mineralization.NEW & NOTEWORTHY We report the discovery that the ecto-nucleotide pyrophosphatase/phosphodiesterase, ENPP2, is an important regulator of early differentiation of bone-forming osteoblasts.
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Affiliation(s)
- Irina L Tourkova
- Research Service, VA Medical Centre, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Quitterie C Larrouture
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Silvia Liu
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Jianhua Luo
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Paul H Schlesinger
- Department of Cell Biology, Washington University, St. Louis, Missouri, United States
| | - Harry C Blair
- Research Service, VA Medical Centre, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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3
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Ferreira CR, Carpenter TO, Braddock DT. ENPP1 in Blood and Bone: Skeletal and Soft Tissue Diseases Induced by ENPP1 Deficiency. ANNUAL REVIEW OF PATHOLOGY 2024; 19:507-540. [PMID: 37871131 PMCID: PMC11062289 DOI: 10.1146/annurev-pathmechdis-051222-121126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The enzyme ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) codes for a type 2 transmembrane glycoprotein that hydrolyzes extracellular ATP to generate pyrophosphate (PPi) and adenosine monophosphate, thereby contributing to downstream purinergic signaling pathways. The clinical phenotypes induced by ENPP1 deficiency are seemingly contradictory and include early-onset osteoporosis in middle-aged adults and life-threatening vascular calcifications in the large arteries of infants with generalized arterial calcification of infancy. The progressive overmineralization of soft tissue and concurrent undermineralization of skeleton also occur in the general medical population, where it is referred to as paradoxical mineralization to highlight the confusing pathophysiology. This review summarizes the clinical presentation and pathophysiology of paradoxical mineralization unveiled by ENPP1 deficiency and the bench-to-bedside development of a novel ENPP1 biologics designed to treat mineralization disorders in the rare disease and general medical population.
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Affiliation(s)
- Carlos R Ferreira
- Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas O Carpenter
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Demetrios T Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA;
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Arima T, Sugimoto K, Taniwaki T, Maeda K, Shibata Y, Tateyama M, Karasugi T, Tokunaga T, Sueyoshi T, Hisanaga S, Masuda T, Uehara Y, Yugami M, Matsushita K, Yonemitsu R, Kawakami J, Yoshimura N, Tanimura S, Kato H, Ito N, Inoue K, Bando K, Nakamura T, Miyamoto T. Cartilage tissues regulate systemic aging via ectonucleotide pyrophosphatase/phosphodiesterase 1 in mice. J Biol Chem 2024; 300:105512. [PMID: 38042486 PMCID: PMC10777000 DOI: 10.1016/j.jbc.2023.105512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 11/09/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023] Open
Abstract
Aging presents fundamental health concerns worldwide; however, mechanisms underlying how aging is regulated are not fully understood. Here, we show that cartilage regulates aging by controlling phosphate metabolism via ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1). We newly established an Enpp1 reporter mouse, in which an EGFP-luciferase sequence was knocked-in at the Enpp1 gene start codon (Enpp1/EGFP-luciferase), enabling detection of Enpp1 expression in cartilage tissues of resultant mice. We then established a cartilage-specific Enpp1 conditional knockout mouse (Enpp1 cKO) by generating Enpp1 flox mice and crossing them with cartilage-specific type 2 collagen Cre mice. Relative to WT controls, Enpp1 cKO mice exhibited phenotypes resembling human aging, such as short life span, ectopic calcifications, and osteoporosis, as well as significantly lower serum pyrophosphate levels. We also observed significant weight loss and worsening of osteoporosis in Enpp1 cKO mice under phosphate overload conditions, similar to global Enpp1-deficient mice. Aging phenotypes seen in Enpp1 cKO mice under phosphate overload conditions were rescued by a low vitamin D diet, even under high phosphate conditions. These findings suggest overall that cartilage tissue plays an important role in regulating systemic aging via Enpp1.
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Affiliation(s)
- Takahiro Arima
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazuki Sugimoto
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takuya Taniwaki
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazuya Maeda
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yuto Shibata
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Makoto Tateyama
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Tatsuki Karasugi
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takuya Tokunaga
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takanao Sueyoshi
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Satoshi Hisanaga
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Tetsuro Masuda
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yusuke Uehara
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masaki Yugami
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kozo Matsushita
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Ryuji Yonemitsu
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Junki Kawakami
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Naoto Yoshimura
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Shuntaro Tanimura
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
| | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
| | - Kenichi Inoue
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Kana Bando
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Takayuki Nakamura
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
| | - Takeshi Miyamoto
- Department of Orthopedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
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Hidaka N, Murata H, Tachikawa K, Osaki K, Sekiyama T, Kinoshita Y, Kato H, Hoshino Y, Kimura S, Sunouchi T, Watanabe S, Nangaku M, Makita N, Michigami T, Ito N. The Effect of Asfotase Alfa on Plasma and Urine Pyrophosphate Levels and Pseudofractures in a Patient With Adult-Onset Hypophosphatasia. JBMR Plus 2023; 7:e10842. [PMID: 38130758 PMCID: PMC10731098 DOI: 10.1002/jbm4.10842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/07/2023] [Accepted: 10/25/2023] [Indexed: 12/23/2023] Open
Abstract
Hypophosphatasia (HPP) is an inherited disease caused by variants of the ALPL gene encoding tissue-nonspecific alkaline phosphatase. Adult-onset HPP (adult HPP), known as a mild form of HPP, develops symptoms involving osteomalacia after the age of 18 years. Asfotase alfa (AA) is a modulated recombinant human alkaline phosphatase (ALP) that has been established as a first-line therapy for severe forms of HPP, such as perinatal and infantile forms. We described a 64-year-old female who presented with pseudofractures in bilateral femur diaphyses and impaired mobility. Low serum ALP activity and a high concentration of urine phosphoethanolamine indicated the diagnosis of HPP, which was confirmed by the identification of a homozygous variant in the ALPL gene (c.319G > A; p.Val107Ile). An in vitro transfection experiment to measure the ALP activity of this novel variant protein was performed, resulting in 40% of the residual enzymatic activity compared with the wild type. AA was initiated to facilitate the union of pseudofracture and to improve mobility. After 6 months, radiographic images revealed the disappearance of fracture lines, and improvement of ambulatory ability was confirmed by the 6-minute walk test (525 to 606 m). The EQ-5D-5L index was also improved (0.757 to 0.895). Within a follow-up period, the levels of urine pyrophosphate corrected by urine creatinine (uPPi/Cre) declined in parallel with the level of plasma PPi (plasma PPi: 6.34 to 1.04 μM, uPPi/Cre: 226.8 to 75.4 nmol/mg). The beneficial effect of AA on pseudofracture healing in adult HPP was presented, although the application of AA should be restricted to patients exhibiting relatively severe manifestations. In addition, a novel pathogenic variant of the ALPL gene was identified with the supportive result of functional analysis. Furthermore, when monitoring patients with HPP treated with AA, uPPi/Cre might be a convenient substitute for plasma PPi, which requires immediate filtration after blood sampling. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Naoko Hidaka
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Hiroaki Murata
- Department of Orthopaedic Surgery, Panasonic Health Insurance OrganizationMatsushita Memorial HospitalOsakaJapan
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Research InstituteOsaka Women's and Children's HospitalOsakaJapan
| | - Keiichi Osaki
- Department of Rehabilitation, Panasonic Health Insurance OrganizationMatsushita Memorial HospitalOsakaJapan
| | - Takashi Sekiyama
- Department of Rehabilitation, Panasonic Health Insurance OrganizationMatsushita Memorial HospitalOsakaJapan
| | - Yuka Kinoshita
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Hajime Kato
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Yoshitomo Hoshino
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Soichiro Kimura
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Takashi Sunouchi
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - So Watanabe
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
- Department of Geriatric Medicine, Graduate School of MedicineThe University of TokyoTokyoJapan
| | - Masaomi Nangaku
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
| | - Noriko Makita
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Research InstituteOsaka Women's and Children's HospitalOsakaJapan
| | - Nobuaki Ito
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
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Zhu Z, He Z, Tang T, Wang F, Chen H, Zhou J, Lin C, Chen G, Wang J, Li J, Liu X, Zhou Z, Liu S. Effect of mechanical stimulation on tissue heterotopic ossification: an in vivo experimental study. Front Physiol 2023; 14:1225898. [PMID: 37900947 PMCID: PMC10600381 DOI: 10.3389/fphys.2023.1225898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/22/2023] [Indexed: 10/31/2023] Open
Abstract
Background: Heterotopic ossification of tendons and ligaments (HOTL) is a common clinical condition characterized by the absence of discernible features and a lack of effective treatment. In vitro experiments have demonstrated that mechanical stimulation can induce cell differentiation toward osteogenesis, thereby promoting heterotopic ossification. Currently, there are few experimental designs aimed at inducing ligament stretching in mice, and the mechanism of heterotopic ossification may not entirely mirror that observed in clinical cases. Therefore, there is an urgent imperative to develop a novel and feasible animal model. Methods: In this study, all the Enpp1 gene deficiency mice (a mouse model with heterotopic ossification of multiple ligaments) were divided into three groups: the control group, the spinal brake group, and the hyperactive group (treadmill training group). An external spinal fixation device was designed to restrict mice's spinal flexion and extension at 6 weeks of age. The brace was adjusted weekly according to the changes in the size of the mice. Additionally, treadmill training was used to increase activity in the spinal ligaments and Achilles tendons of the mice. Micro-CT scanning and HE staining were performed at 12, 20, and 28 W to evaluate the degree of ossification in the spinal ligament and Achilles tendon. What's more, As one of the mechanical stimulation transduction signals, YAP plays a crucial role in promoting osteogenic differentiation of cells. Immunofluorescence was utilized to assess YAP expression levels for the purpose of determining the extent of mechanical stimulation in tissues. Results: Our findings showed that a few ossification lesions were detected behind the vertebral space of mice at 8 weeks of age. Spinal immobilization effectively restricts the flexion and extension of cervical and thoracic vertebrae in mice, delaying spinal ligament ossification and reducing chronic secondary spinal cord injury. Running exercises not only enhance the ossification area of the posterior longitudinal ligament (PLL) and Achilles tendons but also exacerbate secondary spinal cord injury. Further immunofluorescence results revealed a notable increase in YAP expression levels in tissues with severe ossification, suggesting that these tissues may be subjected to higher mechanical stimulation. Conclusion: Mechanical stimulation plays a pivotal role in the process of heterotopic ossification in tissues. Our study provided valid animal models to further explore the pathological mechanism of mechanical stimulation in HOTL development.
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Affiliation(s)
- Zhengya Zhu
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
- Department of Orthopaedic Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Zhongyuan He
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, Orthopaedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Tao Tang
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, Orthopaedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Fuan Wang
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, Orthopaedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Hongkun Chen
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Jiaxiang Zhou
- Department of Orthopaedic Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Chengkai Lin
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Guoliang Chen
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Jianmin Wang
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Jianfeng Li
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Xizhe Liu
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, Orthopaedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Zhiyu Zhou
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, Orthopaedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Shaoyu Liu
- Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopaedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, Orthopaedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Kato H, Braddock DT, Ito N. Genetics of Diffuse Idiopathic Skeletal Hyperostosis and Ossification of the Spinal Ligaments. Curr Osteoporos Rep 2023; 21:552-566. [PMID: 37530996 PMCID: PMC10543536 DOI: 10.1007/s11914-023-00814-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/03/2023] [Indexed: 08/03/2023]
Abstract
PURPOSE OF REVIEW The study aims to provide updated information on the genetic factors associated with the diagnoses 'Diffuse Idiopathic Skeletal Hyperostosis' (DISH), 'Ossification of the Posterior Longitudinal Ligament' (OPLL), and in patients with spinal ligament ossification. RECENT FINDINGS Recent studies have advanced our knowledge of genetic factors associated with DISH, OPLL, and other spinal ossification (ossification of the anterior longitudinal ligament [OALL] and the yellow ligament [OYL]). Several case studies of individuals afflicted with monogenic disorders, such as X-linked hypophosphatemia (XLH), demonstrate the strong association of fibroblast growth factor 23-related hypophosphatemia with OPLL, suggesting that pathogenic variants in PHEX, ENPP1, and DMP1 are associated with FGF23-phosphate wasting phenotype and strong genetic factors placing patients at risk for OPLL. Moreover, emerging evidence demonstrates that heterozygous and compound heterozygous ENPP1 pathogenic variants inducing 'Autosomal Recessive Hypophosphatemic Rickets Type 2' (ARHR2) also place patients at risk for DISH and OPLL, possibly due to the loss of inhibitory plasma pyrophosphate (PPi) which suppresses ectopic calcification and enthesis mineralization. Our findings emphasize the importance of genetic and plasma biomarker screening in the clinical evaluation of DISH and OPLL patients, with plasma PPi constituting an important new biomarker for the identification of DISH and OPLL patients whose disease course may be responsive to ENPP1 enzyme therapy, now in clinical trials for rare calcification disorders.
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Affiliation(s)
- Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | | | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan.
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8
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Review of Basic Research about Ossification of the Spinal Ligaments Focusing on Animal Models. J Clin Med 2023; 12:jcm12051958. [PMID: 36902744 PMCID: PMC10003841 DOI: 10.3390/jcm12051958] [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: 01/31/2023] [Revised: 02/25/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Ossification of the posterior longitudinal ligament (OPLL) is a heterotopic ossification that may cause spinal cord compression. With the recent development of computed tomography (CT) imaging, it is known that patients with OPLL often have complications related to ossification of other spinal ligaments, and OPLL is now considered part of ossification of the spinal ligaments (OSL). OSL is known to be a multifactorial disease with associated genetic and environmental factors, but its pathophysiology has not been clearly elucidated. To elucidate the pathophysiology of OSL and develop novel therapeutic strategies, clinically relevant and validated animal models are needed. In this review, we focus on animal models that have been reported to date and discuss their pathophysiology and clinical relevance. The purpose of this review is to summarize the usefulness and problems of existing animal models and to help further the development of basic research on OSL.
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9
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Ralph D, Levine M, Millán JL, Uitto J, Li Q. Weighing the Evidence for the Roles of Plasma Versus Local Pyrophosphate in Ectopic Calcification Disorders. J Bone Miner Res 2023; 38:457-463. [PMID: 36807615 PMCID: PMC10365072 DOI: 10.1002/jbmr.4791] [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: 12/16/2022] [Revised: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023]
Abstract
Ectopic calcification is characterized by inappropriate deposition of calcium mineral in nonskeletal connective tissues and can cause significant morbidity and mortality, particularly when it affects the cardiovascular system. Identification of the metabolic and genetic determinants of ectopic calcification could help distinguish individuals at the greatest risk of developing these pathological calcifications and could guide development of medical interventions. Inorganic pyrophosphate (PPi ) has long been recognized as the most potent endogenous inhibitor of biomineralization. It has been intensively studied as both a marker and a potential therapeutic for ectopic calcification. Decreased extracellular concentrations of PPi have been proposed to be a unifying pathophysiological mechanism for disorders of ectopic calcification, both genetic and acquired. However, are reduced plasma concentrations of PPi a reliable predictor of ectopic calcification? This perspective article evaluates the literature in favor and against a pathophysiological role of plasma versus tissue PPi dysregulation as a determinant of, and as a biomarker for, ectopic calcification. © 2023 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Douglas Ralph
- Genetics, Genomics and Cancer Biology Ph.D. Program, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, PA, USA.,Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA.,PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael Levine
- Division of Endocrinology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - José Luis Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA.,PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA
| | - Qiaoli Li
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA.,PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA
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10
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Doulgeraki A, Laurent MR. Editorial: Rickets and osteomalacia, from genes to nutrition. Front Endocrinol (Lausanne) 2023; 14:1141888. [PMID: 36742385 PMCID: PMC9893633 DOI: 10.3389/fendo.2023.1141888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/20/2023] Open
Affiliation(s)
- Artemis Doulgeraki
- Department of Bone and Mineral Metabolism, Institute of Child Health, Agia Sophia Children’s Hospital, Athens, Greece
- *Correspondence: Artemis Doulgeraki,
| | - Michaël R. Laurent
- Centre for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium
- Geriatrics Department, Imelda Hospital, Bonheiden, Belgium
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11
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Chunn LM, Bissonnette J, Heinrich SV, Mercurio SA, Kiel MJ, Rutsch F, Ferreira CR. Estimation of ENPP1 deficiency genetic prevalence using a comprehensive literature review and population databases. Orphanet J Rare Dis 2022; 17:421. [PMID: 36461014 PMCID: PMC9717445 DOI: 10.1186/s13023-022-02577-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/20/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND ENPP1 Deficiency-caused by biallelic variants in ENPP1-leads to widespread arterial calcification in early life (Generalized Arterial Calcification of Infancy, GACI) or hypophosphatemic rickets in later life (Autosomal Recessive Hypophosphatemic Rickets type 2, ARHR2). A prior study using the Exome Aggregation Consortium (ExAC)-a database of exomes obtained from approximately 60,000 individuals-estimated the genetic prevalence at approximately 1 in 200,000 pregnancies. METHODS We estimated the genetic prevalence of ENPP1 Deficiency by evaluating allele frequencies from a population database, assuming Hardy-Weinberg equilibrium. This estimate benefitted from a comprehensive literature review using Mastermind ( https://mastermind.genomenon.com/ ), which uncovered additional variants and supporting evidence, a larger population database with approximately 140,000 individuals, and improved interpretation of variants as per current clinical guidelines. RESULTS We estimate a genetic prevalence of approximately 1 in 64,000 pregnancies, thus more than tripling the prior estimate. In addition, the carrier frequency of ENPP1 variants was found to be highest in East Asian populations, albeit based on a small sample. CONCLUSION These results indicate that a significant number of patients with ENPP1 Deficiency remain undiagnosed. Efforts to increase disease awareness as well as expand genetic testing, particularly in non-European populations are warranted, especially now that clinical trials for enzyme replacement therapy, which proved successful in animal models, are underway.
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Affiliation(s)
| | | | | | | | | | - Frank Rutsch
- grid.16149.3b0000 0004 0551 4246Department of General Paediatrics, Muenster University Children’s Hospital, Münster, Germany
| | - Carlos R. Ferreira
- grid.280128.10000 0001 2233 9230Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD USA
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12
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Mercurio SA, Chunn LM, Khursigara G, Nester C, Wray K, Botschen U, Kiel MJ, Rutsch F, Ferreira CR. ENPP1 deficiency: A clinical update on the relevance of individual variants using a locus-specific patient database. Hum Mutat 2022; 43:1673-1705. [PMID: 36150100 DOI: 10.1002/humu.24477] [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: 03/16/2022] [Revised: 09/16/2022] [Accepted: 09/21/2022] [Indexed: 01/24/2023]
Abstract
Loss-of-function variants in the ectonucleotide pyrophosphatase/phosphodiesterase family member 1 (ENPP1) cause ENPP1 Deficiency, a rare disorder characterized by pathological calcification, neointimal proliferation, and impaired bone mineralization. The consequence of ENPP1 Deficiency is a broad range of age dependent symptoms and morbidities including cardiovascular complications and 50% mortality in infants, autosomal recessive hypophosphatemic rickets type 2 (ARHR2) in children, and joint pain, osteomalacia and enthesopathies in adults. Recent research continues to add to the growing clinical presentation profile as well as expanding the role of ENPP1 itself. Here we review the current knowledge on the spectrum of clinical and genetic findings of ENPP1 Deficiency reported in patients diagnosed with GACI or ARHR2 phenotypes using a comprehensive database of known ENPP1 variants with associated clinical data. A total of 108 genotypes were identified from 154 patients. Of the 109 ENPP1 variants reviewed, 72.5% were demonstrably disease-causing, a threefold increase in pathogenic/likely pathogenic variants over other databases. There is substantial heterogeneity in disease severity, even among patients with the same variant. The approach to creating a continuously curated database of ENPP1 variants accessible to clinicians is necessary to increase the diagnostic yield of clinical genetic testing and accelerate diagnosis of ENPP1 Deficiency.
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Affiliation(s)
- Stephanie A Mercurio
- Department of Data Science, Curation Division, Genomenon Inc., Ann Arbor, Michigan, USA
| | - Lauren M Chunn
- Department of Scientific Communication and Strategy, Genomenon Inc., Ann Arbor, Michigan, USA
| | - Gus Khursigara
- Department of Medical Affairs, Inozyme Pharma, Boston, Massachusetts, USA
| | - Catherine Nester
- Department of Physician and Patient Strategies, Inozyme Pharma, Boston, Massachusetts, USA
| | - Kathleen Wray
- Department of Medical Affairs, Inozyme Pharma, Boston, Massachusetts, USA
| | - Ulrike Botschen
- Department of General Paediatrics, Muenster University Children's Hospital, Münster, Germany
| | - Mark J Kiel
- Department of Scientific Communication and Strategy, Genomenon Inc., Ann Arbor, Michigan, USA
| | - Frank Rutsch
- Department of General Paediatrics, Muenster University Children's Hospital, Münster, Germany
| | - Carlos R Ferreira
- Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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13
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Yang K, Li J, Tao L. Purine metabolism in the development of osteoporosis. Biomed Pharmacother 2022; 155:113784. [DOI: 10.1016/j.biopha.2022.113784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/17/2022] Open
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14
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Hoshino Y, Hidaka N, Kato H, Koga M, Taniguchi Y, Kobayashi H, Nangaku M, Makita N, Ito N. Incidence of ossification of the spinal ligaments in acromegaly patients. Bone Rep 2022; 17:101628. [PMID: 36299702 PMCID: PMC9589022 DOI: 10.1016/j.bonr.2022.101628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/10/2022] [Accepted: 10/15/2022] [Indexed: 11/05/2022] Open
Abstract
Some previous case reports have implied a relationship between acromegaly and ossification of the spinal ligaments. However, there have been no reports of a case series exploring the incidence of ossification of the spinal ligaments in patients with acromegaly. To this end, computed tomography (CT) of the spine in 10 consecutive patients with acromegaly was examined in this study. Five out of 10 patients had ossification of the spinal ligaments. Among them, two patients had ossification of the posterior longitudinal ligament (OPLL), which was noticeably higher than the prevalence of OPLL in the general adult population (1.9–4.3 %). Body mass index was significantly higher in the group with spinal ligament ossification (p = 0.03), but there were no significant differences in age, sex, serum phosphate, albumin-adjusted calcium, growth hormone (GH), standard deviation of insulin-like growth factor-1 (IGF-1), or the incidence of diabetes mellitus between the groups with or without ossification of the spinal ligaments. The ossification index (OS index) was used to determine the severity of spinal ligament ossification, and there were no significant correlations between the OS index and GH or IGF-1 (p = 0.51 and 0.75, respectively). This study was the first to report a high prevalence of spinal ossification in patients with acromegaly. In conclusion, this study suggested a possible association between acromegaly and ossification of the spinal ligaments, although the number of patients was insufficient to draw a conclusion. Acromegaly patients should be tested to confirm, or rule out, spinal ossification, and further studies to clarify the underlying mechanism of spinal ossification in acromegaly patients are warranted.
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Affiliation(s)
- Yoshitomo Hoshino
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Naoko Hidaka
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Minae Koga
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Yuki Taniguchi
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Hiroshi Kobayashi
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Noriko Makita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
- Corresponding author at: Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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15
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Zimmerman K, Li X, von Kroge S, Stabach P, Lester ER, Chu EY, Srivastava S, Somerman MJ, Tommasini SM, Busse B, Schinke T, Carpenter TO, Oheim R, Braddock DT. Catalysis-Independent ENPP1 Protein Signaling Regulates Mammalian Bone Mass. J Bone Miner Res 2022; 37:1733-1749. [PMID: 35773783 PMCID: PMC9709593 DOI: 10.1002/jbmr.4640] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/09/2022] [Accepted: 06/17/2022] [Indexed: 11/06/2022]
Abstract
Biallelic ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) deficiency induces vascular/soft tissue calcifications in generalized arterial calcification of infancy (GACI), and low bone mass with phosphate-wasting rickets in GACI survivors (autosomal hypophosphatemic rickets type-2). ENPP1 haploinsufficiency induces early-onset osteoporosis and mild phosphate wasting in adults. Both conditions demonstrate the unusual combination of reduced accrual of skeletal mineral, yet excess and progressive heterotopic mineralization. ENPP1 is the only enzyme that generates extracellular pyrophosphate (PPi), a potent inhibitor of both bone and heterotopic mineralization. Life-threatening vascular calcification in ENPP1 deficiency is due to decreased plasma PPi; however, the mechanism by which osteopenia results is not apparent from an understanding of the enzyme's catalytic activity. To probe for catalysis-independent ENPP1 pathways regulating bone, we developed a murine model uncoupling ENPP1 protein signaling from ENPP1 catalysis, Enpp1T238A mice. In contrast to Enpp1asj mice, which lack ENPP1, Enpp1T238A mice have normal trabecular bone microarchitecture and favorable biomechanical properties. However, both models demonstrate low plasma Pi and PPi, increased fibroblast growth factor 23 (FGF23), and by 23 weeks, osteomalacia demonstrating equivalent phosphate wasting in both models. Reflecting findings in whole bone, calvarial cell cultures from Enpp1asj mice demonstrated markedly decreased calcification, elevated transcription of Sfrp1, and decreased nuclear β-catenin signaling compared to wild-type (WT) and Enpp1T238A cultures. Finally, the decreased calcification and nuclear β-catenin signaling observed in Enpp1asj cultures was restored to WT levels by knockout of Sfrp1. Collectively, our findings demonstrate that catalysis-independent ENPP1 signaling pathways regulate bone mass via the expression of soluble Wnt inhibitors such as secreted frizzled-related protein 1 (SFRP1), whereas catalysis dependent pathways regulate phosphate homeostasis through the regulation of plasma FGF23. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Kristin Zimmerman
- Department of Pathology, Yale University School of Medicine, New Haven Connecticut, 06510
| | - Xiaochen Li
- Department of Pathology, Yale University School of Medicine, New Haven Connecticut, 06510
| | - Simon von Kroge
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Paul Stabach
- Department of Pathology, Yale University School of Medicine, New Haven Connecticut, 06510
| | - Ethan R. Lester
- Department of Pathology, Yale University School of Medicine, New Haven Connecticut, 06510
| | - Emily Y. Chu
- National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD, USA
- Department of General Dentistry, Operative Division, University of Maryland School of Dentistry, Baltimore, Maryland, 21202
| | - Shivani Srivastava
- Department of Pathology, Yale University School of Medicine, New Haven Connecticut, 06510
| | - Martha J. Somerman
- National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Steven M. Tommasini
- Department of Orthopædics and Rehabilitation, Yale University School of Medicine, New Haven Connecticut, 06510
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Thomas O. Carpenter
- Department of Pediatrics at Yale University School of Medicine, New Haven Connecticut, 06510
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Demetrios T. Braddock
- Department of Pathology, Yale University School of Medicine, New Haven Connecticut, 06510
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16
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Adult Presentation of X-Linked Hypophosphatemia. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Adult X-linked hypophosphatemia (XLH) patients present with specific symptoms, including enthesopathies (e.g., ossification of longitudinal ligaments (OPLL), osteophytes around large joints, and enthesopathy in the Achilles tendons), early osteoarthritis, the development of severe secondary and tertiary hyperparathyroidism (SHPT/THPT), and the subsequent progression of chronic kidney disease (CKD). In addition, these patients exhibit the typical phenotypes of osteomalacia, such as pseudofracture and fracture in weight-bearing bones, odontitis, and tooth abscesses. The mechanism underlying enthesopathy development is unknown; however, a common underlying mechanism among XLH and autosomal recessive hypophosphatemic rickets (ARHR1/2) due to mutations in PHEX, DMP1, and ENPP1 is assumed. Clarification of the pathogenesis and drug discovery for this complication is an urgent issue, as many adult XLH patients suffer subsequent debilitating nervous symptoms or impingement syndrome, and existing treatments are ineffective. Severe SHPT and THPT are associated with conventional therapy, including active vitamin D and phosphate supplementation, and complicated and careful adjustment of dosages by experienced clinicians is required to avoid SHPT/THPT. Burosumab is a very effective therapy without risk for the development of SHPT/THPT. However, indications for this drug should be carefully considered, along with cost-effectiveness, guidelines or recommendations, and the health care system of each country.
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17
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Choe Y, Shin CH, Lee YA, Kim MJ, Lee YJ. Case Report and Review of Literature: Autosomal Recessive Hypophosphatemic Rickets Type 2 Caused by a Pathogenic Variant in ENPP1 Gene. Front Endocrinol (Lausanne) 2022; 13:911672. [PMID: 35966073 PMCID: PMC9374118 DOI: 10.3389/fendo.2022.911672] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/01/2022] [Indexed: 11/29/2022] Open
Abstract
Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) is a rare form of hereditary rickets, which is characterized by defective bone mineralization and renal phosphate wasting due to a loss-of-function variant in the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene. Although pathogenic variant of ENPP1 has been known to manifest other phenotypes including arterial calcification, hearing loss, ossification of posterior longitudinal ligament, or pseudoxanthoma elasticum, there have been few reports including systematic examination in individuals diagnosed with ARHR2 to date. Herein, we report a case of ARHR2 with a bi-allelic pathogenic variant of ENPP1, in which the patient presented with gait abnormalities with severe genu varum at 26 months of age. Targeted gene panel sequencing was performed to investigate the genetic cause of rickets, and a homozygous nonsense variant in ENPP1, c.783C>G (p.Tyr261*), was identified. The patient was treated with oral phosphate and active vitamin D supplements and underwent corrective osteotomy for varus deformity. His phenotype was limited to rickets. A periodic systematic evaluation is needed to identify any comorbidities in ARHR2 patients since ENPP1 variants may present phenotypes other than rickets and symptoms may evolve or change over time.
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Affiliation(s)
- Yunsoo Choe
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, South Korea
| | - Choong Ho Shin
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, South Korea
| | - Young Ah Lee
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, South Korea
| | - Man Jin Kim
- Department of Genomic Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Yun Jeong Lee
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, South Korea
- *Correspondence: Yun Jeong Lee,
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