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Pignolo RJ, Kaplan FS, Wang H. Cell Senescence in Heterotopic Ossification. Biomolecules 2024; 14:485. [PMID: 38672501 PMCID: PMC11047966 DOI: 10.3390/biom14040485] [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: 03/26/2024] [Revised: 04/08/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
The formation of bone outside the normal skeleton, or heterotopic ossification (HO), occurs through genetic and acquired mechanisms. Fibrodysplasia ossificans progressiva (FOP), the most devastating genetic condition of HO, is due to mutations in the ACVR1/ALK2 gene and is relentlessly progressive. Acquired HO is mostly precipitated by injury or orthopedic surgical procedures but can also be associated with certain conditions related to aging. Cellular senescence is a hallmark of aging and thought to be a tumor-suppressive mechanism with characteristic features such as irreversible growth arrest, apoptosis resistance, and an inflammatory senescence-associated secretory phenotype (SASP). Here, we review possible roles for cellular senescence in HO and how targeting senescent cells may provide new therapeutic approaches to both FOP and acquired forms of HO.
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Affiliation(s)
- Robert J. Pignolo
- Department of Medicine, Section of Geriatric Medicine & Gerontology, Mayo Clinic, Rochester, MN 55905, USA
- Divisions of Endocrinology and Hospital Internal Medicine, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA;
| | - Frederick S. Kaplan
- Department of Orthopaedic Surgery, The Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA;
- Department of Medicine, The Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA
- The Center for Research in FOP and Related Disorders, The Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Haitao Wang
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA;
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
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2
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Anwar S, Yokota T. Navigating the Complex Landscape of Fibrodysplasia Ossificans Progressiva: From Current Paradigms to Therapeutic Frontiers. Genes (Basel) 2023; 14:2162. [PMID: 38136984 PMCID: PMC10742611 DOI: 10.3390/genes14122162] [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: 09/25/2023] [Revised: 11/08/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is an enigmatic, ultra-rare genetic disorder characterized by progressive heterotopic ossification, wherein soft connective tissues undergo pathological transformation into bone structures. This incapacitating process severely limits patient mobility and poses formidable challenges for therapeutic intervention. Predominantly caused by missense mutations in the ACVR1 gene, this disorder has hitherto defied comprehensive mechanistic understanding and effective treatment paradigms. This write-up offers a comprehensive overview of the contemporary understanding of FOP's complex pathobiology, underscored by advances in molecular genetics and proteomic studies. We delve into targeted therapy, spanning genetic therapeutics, enzymatic and transcriptional modulation, stem cell therapies, and innovative immunotherapies. We also highlight the intricate complexities surrounding clinical trial design for ultra-rare disorders like FOP, addressing fundamental statistical limitations, ethical conundrums, and methodological advancements essential for the success of interventional studies. We advocate for the adoption of a multi-disciplinary approach that converges bench-to-bedside research, clinical expertise, and ethical considerations to tackle the challenges of ultra-rare diseases like FOP and comparable ultra-rare diseases. In essence, this manuscript serves a dual purpose: as a definitive scientific resource for ongoing and future FOP research and a call to action for innovative solutions to address methodological and ethical challenges that impede progress in the broader field of medical research into ultra-rare conditions.
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Affiliation(s)
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;
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3
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Nagar G, Mittal P, Gupta SRR, Pahuja M, Sanger M, Mishra R, Singh A, Singh IK. Multi-omics therapeutic perspective on ACVR1 gene: from genetic alterations to potential targeting. Brief Funct Genomics 2022; 22:123-142. [PMID: 36003055 DOI: 10.1093/bfgp/elac026] [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: 04/29/2022] [Revised: 07/04/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Activin A receptor type I (ACVR1), a transmembrane serine/threonine kinase, belongs to the transforming growth factor-β superfamily, which signals via phosphorylating the downstream effectors and SMAD transcription factors. Its central role in several biological processes and intracellular signaling is well known. Genetic variation in ACVR1 has been associated with a rare disease, fibrodysplasia ossificans progressive, and its somatic alteration is reported in rare cancer diffuse intrinsic pontine glioma. Furthermore, altered expression or variation of ACVR1 is associated with multiple pathologies such as polycystic ovary syndrome, congenital heart defects, diffuse idiopathic skeletal hyperostosis, posterior fossa ependymoma and other malignancies. Recent advancements have witnessed ACVR1 as a potential pharmacological target, and divergent promising approaches for its therapeutic targeting have been explored. This review highlights the structural and functional characteristics of receptor ACVR1, associated signaling pathways, genetic variants in several diseases and cancers, protein-protein interaction, gene expression, regulatory miRNA prediction and potential therapeutic targeting approaches. The comprehensive knowledge will offer new horizons and insights into future strategies harnessing its therapeutic potential.
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Current challenges and opportunities in the care of patients with fibrodysplasia ossificans progressiva (FOP): an international, multi-stakeholder perspective. Orphanet J Rare Dis 2022; 17:168. [PMID: 35436894 PMCID: PMC9014788 DOI: 10.1186/s13023-022-02224-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/06/2022] [Indexed: 11/24/2022] Open
Abstract
Background Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare, disabling genetic disorder characterized by congenital malformations of the great toes and progressive heterotopic ossification of soft and connective tissues. Assiduous attention to the unmet needs of this patient community is crucial to prevent potential iatrogenic harm and optimize care for individuals with FOP. Objective To gather international expert opinion and real-world experience on the key challenges for individuals with FOP and their families, highlight critical gaps in care, communication, and research, and provide recommendations for improvement. Methods An international group of expert clinicians, patients and patient advocates, caregivers and representatives from the international FOP community participated in a virtual, half-day meeting on 22 March 2021 to discuss the key unmet needs of individuals with FOP. Results Individuals with FOP often face the frustration of long diagnostic journeys, the burden of self-advocacy and the navigation of novel care pathways. Globally, patients with FOP are also confronted with inequities in access to diagnosis and specialist care, and consequently, unequal access to registries, clinical trials, and essential support from patient associations. Organizations such as the International FOP Association, the International Clinical Council on FOP, and national FOP organizations work to provide information, facilitate access to expert clinical guidance, nurture patient empowerment, fund FOP research and/or foster meaningful collaborations with the research community. The non-profit Tin Soldiers Global FOP Patient Search program aims to identify and provide a pathway to diagnosis and care for individuals with FOP, particularly in underserved communities. Such global initiatives and the increasingly widespread use of telemedicine and digital platforms offer opportunities to improve vital access to care and research. Conclusions This multi-stakeholder perspective highlights some of the unmet needs of individuals with FOP and their families. Regional and international organizations play an important role in improving the quality of life of those they reach in the global FOP community. However, globally, fundamental issues remain around raising awareness of FOP among healthcare professionals, identifying individuals with FOP, reducing time to diagnosis, and ensuring access to best practice in care, support, and clinical research. Medical writing support was industry-sponsored. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02224-w.
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Wang H, Zhang Q, Kaplan FS, Pignolo RJ. Clearance of Senescent Cells From Injured Muscle Abrogates Heterotopic Ossification in Mouse Models of Fibrodysplasia Ossificans Progressiva. J Bone Miner Res 2022; 37:95-107. [PMID: 34633114 PMCID: PMC8770661 DOI: 10.1002/jbmr.4458] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/19/2021] [Accepted: 10/02/2021] [Indexed: 11/10/2022]
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease caused by mutations in activin A receptor type I/activin-like kinase 2 (ACVR1/ALK2), a bone morphogenetic protein (BMP) type I receptor, resulting in the formation of extraskeletal or heterotopic ossification (HO) and other features consistent with premature aging. During the first decade of life, episodic bouts of inflammatory swellings (flare-ups) occur, which are typically triggered by soft tissue trauma. Through an endochondral process, these exacerbations ultimately result in skeletal muscles, tendons, ligaments, fascia, and aponeuroses transforming into ectopic bone, rendering movement impossible. We have previously shown that soft tissue injury causes early FOP lesions characterized by cellular hypoxia, cellular damage, and local inflammation. Here we show that muscle injury in FOP also results in senescent cell accumulation, and that senescence promotes tissue reprogramming toward a chondrogenic fate in FOP muscle but not wild-type (WT) muscle. Using a combination of senolytic drugs we show that senescent cell clearance and reduction in the senescence associated secretory phenotype (SASP) ameliorate HO in mouse models of FOP. We conclude that injury-induced senescent cell burden and the SASP contribute to FOP lesion formation and that tissue reprogramming in FOP is mediated by cellular senescence, altering myogenic cell fate toward a chondrogenic cell fate. Furthermore, pharmacological removal of senescent cells abrogates tissue reprogramming and HO formation. Here we provide proof-of-principle evidence for senolytic drugs as a future therapeutic strategy in FOP. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Haitao Wang
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Medicine, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Qiang Zhang
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Medicine, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Frederick S Kaplan
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA, USA.,Department of Medicine, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA, USA.,The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA, USA
| | - Robert J Pignolo
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Medicine, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA
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Crohn's Disease in a Patient With Fibrodysplasia Ossificans Progressiva. ACG Case Rep J 2022; 9:e00737. [PMID: 35097150 PMCID: PMC8791042 DOI: 10.14309/crj.0000000000000737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 10/06/2021] [Indexed: 11/17/2022] Open
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Kaplan FS, Groppe JC, Xu M, Towler OW, Grunvald E, Kalunian K, Kallish S, Al Mukaddam M, Pignolo RJ, Shore EM. An ACVR1 R375P pathogenic variant in two families with mild fibrodysplasia ossificans progressiva. Am J Med Genet A 2021; 188:806-817. [PMID: 34854557 DOI: 10.1002/ajmg.a.62585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/06/2021] [Accepted: 11/02/2021] [Indexed: 11/11/2022]
Abstract
Genetic variants are vital in informing clinical phenotypes, aiding physical diagnosis, guiding genetic counseling, understanding the molecular basis of disease, and potentially stimulating drug development. Here we describe two families with an ultrarare ACVR1 gain-of-function pathogenic variant (codon 375, Arginine > Proline; ACVR1R375P ) responsible for a mild nonclassic fibrodysplasia ossificans progressiva (FOP) phenotype. Both families include people with the ultrarare ACVR1R375P variant who exhibit features of FOP while other individuals currently do not express any clinical signs of FOP. Thus, the mild ACVR1R375P variant greatly expands the scope and understanding of this rare disorder.
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Affiliation(s)
- Frederick S Kaplan
- Department of Orthopaedic Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Medicine, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Center for Research in FOP & Related Disorders, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jay C Groppe
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - Meiqi Xu
- Department of Orthopaedic Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Center for Research in FOP & Related Disorders, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - O Will Towler
- Department of Orthopaedic Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Center for Research in FOP & Related Disorders, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eduardo Grunvald
- Division of General Internal Medicine, The Department of Medicine, The University of California San Diego, San Diego, California, USA
| | - Kenneth Kalunian
- Division of Rheumatology, Allergy and Immunology, The Department of Medicine, UC San Diego School of Medicine, La Jolla, California, USA
| | - Staci Kallish
- The Center for Research in FOP & Related Disorders, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Translational Medicine and Human Genetics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mona Al Mukaddam
- Department of Orthopaedic Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Medicine, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Center for Research in FOP & Related Disorders, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert J Pignolo
- The Department of Medicine, The Mayo Clinic, Rochester, Minnesota, USA
| | - Eileen M Shore
- Department of Orthopaedic Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Center for Research in FOP & Related Disorders, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Genetics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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8
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Pignolo RJ, Pacifici M. Retinoid Agonists in the Targeting of Heterotopic Ossification. Cells 2021; 10:cells10113245. [PMID: 34831466 PMCID: PMC8617746 DOI: 10.3390/cells10113245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 12/25/2022] Open
Abstract
Retinoids are metabolic derivatives of vitamin A and regulate the function of many tissues and organs both prenatally and postnatally. Active retinoids, such as all trans-retinoic acid, are produced in the cytoplasm and then interact with nuclear retinoic acid receptors (RARs) to up-regulate the transcription of target genes. The RARs can also interact with target gene response elements in the absence of retinoids and exert a transcriptional repression function. Studies from several labs, including ours, showed that chondrogenic cell differentiation and cartilage maturation require (i) the absence of retinoid signaling and (ii) the repression function by unliganded RARs. These and related insights led to the proposition that synthetic retinoid agonists could thus represent pharmacological agents to inhibit heterotopic ossification (HO), a process that recapitulates developmental skeletogenesis and involves chondrogenesis, cartilage maturation, and endochondral ossification. One form of HO is acquired and is caused by injury, and another severe and often fatal form of it is genetic and occurs in patients with fibrodysplasia ossificans progressiva (FOP). Mouse models of FOP bearing mutant ACVR1R206H, characteristic of most FOP patients, were used to test the ability of the retinoid agonists selective for RARα and RARγ against spontaneous and injury-induced HO. The RARγ agonists were found to be most effective, and one such compound, palovarotene, was selected for testing in FOP patients. The safety and effectiveness data from recent and ongoing phase II and phase III clinical trials support the notion that palovarotene may represent a disease-modifying treatment for patients with FOP. The post hoc analyses showed substantial efficacy but also revealed side effects and complications, including premature growth plate closure in some patients. Skeletally immature patients will need to be carefully weighed in any future regulatory indications of palovarotene as an important therapeutic option in FOP.
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Affiliation(s)
- Robert J. Pignolo
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Correspondence:
| | - Maurizio Pacifici
- Translational Research Program in Pediatric Orthopedics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
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Kaplan FS, Teachey DT, Andolina JR, Siegel DM, Mancilla EE, Hsiao EC, Al Mukaddam M, Rocke DM, Pignolo RJ. Off-on-off-on use of imatinib in three children with fibrodysplasia ossificans progressiva. Bone 2021; 150:116016. [PMID: 34022457 DOI: 10.1016/j.bone.2021.116016] [Citation(s) in RCA: 6] [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: 02/21/2021] [Revised: 05/05/2021] [Accepted: 05/15/2021] [Indexed: 11/21/2022]
Abstract
The compassionate use of available medications with unproven efficacy is often in conflict with their clinical evaluation in placebo-controlled clinical trials. For ultra-rare diseases where no approved treatments exist, such as fibrodysplasia ossificans progressiva (FOP), routine clinical trial enrollment for available medications may be difficult to achieve. Therefore adaptive methods of evaluation are often desirable. Off-on-off-on (O4) approaches offer an opportunity to rapidly assess the potential symptomatic efficacy and tolerability of a medication with a limited number of patients and may aid in the design of more focused clinical trials that are amenable to enrollment. Here we report three children with classic FOP who had recalcitrant flare-ups of the back and who had been treated with an O4 regimen of imatinib. In all three children, fewer flare-ups, decreased swelling and improved function with activities of daily living were reported by the parents and treating physician when the children were "on" imatinib than when they were "off" imatinib. The median time to improvement on imatinib was 2-3 weeks. The anecdotal O4 experience with imatinib reported here in three children with FOP who had recalcitrant flare-ups of the back supports the design of a brief placebo controlled trial to assess the potential efficacy of imatinib in reducing the symptoms in children with refractory flare-ups of FOP. A tool to prospectively measure and quantitate flare-up symptoms is presently being developed and validated and will be used for such a study.
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Affiliation(s)
- Frederick S Kaplan
- The Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, United States of America; The Department of Medicine, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, United States of America; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, United States of America.
| | - David T Teachey
- The Division of Oncology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States of America.
| | - Jeffrey R Andolina
- The Department of Pediatrics, Division of Hematology-Oncology, University of Rochester School of Medicine, Rochester, NY 14642, United States of America.
| | - David M Siegel
- Division of Pediatric Rheumatology, Department of Pediatrics, University of Rochester School of Medicine, Rochester, NY 14642, United States of America.
| | - Edna E Mancilla
- The Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States of America.
| | - Edward C Hsiao
- The Division of Endocrinology and Metabolism, the UCSF Metabolic Bone Clinic, the Institute for Human Genetics, University of California- San Francisco, San Francisco, CA, United States of America.
| | - Mona Al Mukaddam
- The Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, United States of America; The Department of Medicine, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, United States of America; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, United States of America.
| | - David M Rocke
- The Division of Biostatistics, Department of Biomedical Engineering, University of California - Davis, Davis, CA, United States of America.
| | - Robert J Pignolo
- The Department of Medicine, The Mayo Clinic, Rochester, MN 55905, United States of America.
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Wang H, De Cunto CL, Pignolo RJ, Kaplan FS. Spatial patterns of heterotopic ossification in fibrodysplasia ossificans progressiva correlate with anatomic temperature gradients. Bone 2021; 149:115978. [PMID: 33915334 DOI: 10.1016/j.bone.2021.115978] [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: 12/23/2020] [Revised: 03/23/2021] [Accepted: 04/21/2021] [Indexed: 09/30/2022]
Abstract
Progressive heterotopic ossification (HO) is a hallmark of fibrodysplasia ossificans progressiva (FOP); however, this tissue transformation is not random. Rather, we noticed that HO in FOP progresses in well-defined but inexplicable spatial and temporal patterns that correlate precisely with infrared thermographs of the human body. FOP is caused by gain-of-function mutations in Activin A receptor type I (ACVR1/ALK2), a bone morphogenetic protein (BMP) type I receptor kinase. As with all enzymes, the activity of ACVR1 is temperature-dependent. We hypothesized that connective tissue progenitor cells that express the common heterozygous ACVR1R206H mutation (FOP CTPCs) exhibit a dysregulated temperature response compared to control CTPCs and that the temperature of FOP CTPCs that initiate and sustain HO at various anatomic sites determines, in part, the anatomic distribution of HO in FOP. We compared BMP pathway signaling at a range of physiologic temperatures in primary CTPCs isolated from FOP patients (n = 3) and unaffected controls (n = 3) and found that BMP pathway signaling and resultant chondrogenesis were amplified in FOP CTPCs compared to control CTPCs (p < 0.05). We conclude that the anatomic distribution of HO in FOP may be due, in part, to a dyregulated temperature response in FOP CTPCs that reflect anatomic location. While the association of temperature gradients with spatial patterns of HO in FOP does not demonstrate causality, our findings provide a paradigm for the physiologic basis of the anatomic distribution of HO in FOP and unveil a novel therapeutic target that might be exploited for this disabling condition.
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Affiliation(s)
- Haitao Wang
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Medicine, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Carmen L De Cunto
- Department of Pediatrics, Pediatric Rheumatology Section, Hospital Italiano de Buenos Aires, Gascón 450, 1181 Ciudad Autónoma de Buenos Aires, Argentina
| | - Robert J Pignolo
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Medicine, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA.
| | - Frederick S Kaplan
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of the Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA.
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11
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Kaplan FS, Al Mukaddam M, Stanley A, Towler OW, Shore EM. Fibrodysplasia ossificans progressiva (FOP): A disorder of osteochondrogenesis. Bone 2020; 140:115539. [PMID: 32730934 PMCID: PMC7502483 DOI: 10.1016/j.bone.2020.115539] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 07/01/2020] [Accepted: 07/04/2020] [Indexed: 10/23/2022]
Abstract
Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder of extraskeletal bone formation, but could appropriately be viewed as a seminal disorder of osteochondrogenesis. Many, if not most, of the musculoskeletal features of FOP are related to dysregulated chondrogenesis including abnormal articular cartilage formation, abnormal diarthrodial joint specification, growth plate dysplasia, osteochondroma formation, heterotopic endochondral ossification (HEO), and precocious arthropathy. In FOP, causative activating mutations of Activin receptor A type I (ACVR1), a bone morphogenetic protein (BMP) type I receptor, are responsible for the osteochondrodysplasia that impacts developmental phenotypes as well as postnatal features of this illustrative disorder. Here, we highlight the myriad developmental and postnatal effects on osteochondrogenesis that emanate directly from mutant ACVR1 and dysregulated bone morphogenetic protein (BMP) signaling in FOP.
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Affiliation(s)
- Frederick S Kaplan
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Mona Al Mukaddam
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Alexandra Stanley
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - O Will Towler
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Eileen M Shore
- Department of Orthopaedic Surgery, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA; The Center for Research in FOP & Related Disorders, The Perelman School of Medicine of The University of Pennsylvania, Philadelphia, PA 19104, USA.
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