1
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Yaynishet YA, Salah FO, Gebregiorgis BT, Mume AS, Damtew HD, Amare TZ, Manaleh TM. Fibrodysplasia ossificans progressiva: Two case reports. Radiol Case Rep 2024; 19:2973-2977. [PMID: 38737178 PMCID: PMC11087907 DOI: 10.1016/j.radcr.2024.04.019] [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: 02/26/2024] [Accepted: 04/08/2024] [Indexed: 05/14/2024] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare and progressively debilitating disorder affecting 1 in 2 million individuals. It is characterized by the progressive ossification of soft tissues into ectopic bone and congenital malformations of the great toes. FOP leads to significant disability and can result in death due to thoracic insufficiency syndrome. These case reports examine the presentation, diagnosis, and management of FOP, highlighting the diagnostic challenges inherent in managing such rare conditions because of their unique clinical features. They underscore the need for increased awareness among healthcare practitioners to ensure early diagnosis and the implementation of effective management strategies.
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Affiliation(s)
- Yodit Abraham Yaynishet
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
| | - Fathia Omer Salah
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
| | - Bemnet Taye Gebregiorgis
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
| | - Abdulmejid Suleyman Mume
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
| | - Henok Dessalegn Damtew
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
| | - Tinsae Zelalem Amare
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
| | - Tilahun Mengistu Manaleh
- Addis Ababa University, College of Health Sciences, Department of Radiology, Addis Ababa, Ethiopia
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2
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Davis AJ, Brooijmans N, Brubaker JD, Stevison F, LaBranche TP, Albayya F, Fleming P, Hodous BL, Kim JL, Kim S, Lobbardi R, Palmer M, Sheets MP, Vassiliadis J, Wang R, Williams BD, Wilson D, Xu L, Zhu XJ, Bouchard K, Hunter JW, Graul C, Greenblatt E, Hussein A, Lyon M, Russo J, Stewart R, Dorsch M, Guzi TJ, Kadambi V, Lengauer C, Garner AP. An ALK2 inhibitor, BLU-782, prevents heterotopic ossification in a mouse model of fibrodysplasia ossificans progressiva. Sci Transl Med 2024; 16:eabp8334. [PMID: 38809966 DOI: 10.1126/scitranslmed.abp8334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 05/07/2024] [Indexed: 05/31/2024]
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease driven by gain-of-function variants in activin receptor-like kinase 2 (ALK2), the most common variant being ALK2R206H. In FOP, ALK2 variants display increased and dysregulated signaling through the bone morphogenetic protein (BMP) pathway resulting in progressive and permanent replacement of skeletal muscle and connective tissues with heterotopic bone, ultimately leading to severe debilitation and premature death. Here, we describe the discovery of BLU-782 (IPN60130), a small-molecule ALK2R206H inhibitor developed for the treatment of FOP. A small-molecule library was screened in a biochemical ALK2 binding assay to identify potent ALK2 binding compounds. Iterative rounds of structure-guided drug design were used to optimize compounds for ALK2R206H binding, ALK2 selectivity, and other desirable pharmacokinetic properties. BLU-782 preferentially bound to ALK2R206H with high affinity, inhibiting signaling from ALK2R206H and other rare FOP variants in cells in vitro without affecting signaling of closely related homologs ALK1, ALK3, and ALK6. In vivo efficacy of BLU-782 was demonstrated using a conditional knock-in ALK2R206H mouse model, where prophylactic oral dosing reduced edema and prevented cartilage and heterotopic ossification (HO) in both muscle and bone injury models. BLU-782 treatment preserved the normal muscle-healing response in ALK2R206H mice. Delayed dosing revealed a short 2-day window after injury when BLU-782 treatment prevented HO in ALK2R206H mice, but dosing delays of 4 days or longer abrogated HO prevention. Together, these data suggest that BLU-782 may be a candidate for prevention of HO in FOP.
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Affiliation(s)
- Alison J Davis
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | | | | | - Faith Stevison
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | | | - Faris Albayya
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Paul Fleming
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Brian L Hodous
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Joseph L Kim
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Sean Kim
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Riadh Lobbardi
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Michael Palmer
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | | | | | - Ruduan Wang
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | | | - Douglas Wilson
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Lan Xu
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Xing Julia Zhu
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | | | | | | | | | | | | | | | | | - Marion Dorsch
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Timothy J Guzi
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
| | - Vivek Kadambi
- Blueprint Medicines Corporation, Cambridge, MA 02139, USA
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3
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Mejias Rivera L, Shore EM, Mourkioti F. Cellular and Molecular Mechanisms of Heterotopic Ossification in Fibrodysplasia Ossificans Progressiva. Biomedicines 2024; 12:779. [PMID: 38672135 PMCID: PMC11048698 DOI: 10.3390/biomedicines12040779] [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: 03/12/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a debilitating genetic disorder characterized by recurrent episodes of heterotopic ossification (HO) formation in muscles, tendons, and ligaments. FOP is caused by a missense mutation in the ACVR1 gene (activin A receptor type I), an important signaling receptor involved in endochondral ossification. The ACVR1R206H mutation induces increased downstream canonical SMAD-signaling and drives tissue-resident progenitor cells with osteogenic potential to participate in endochondral HO formation. In this article, we review aberrant ACVR1R206H signaling and the cells that give rise to HO in FOP. FOP mouse models and lineage tracing analyses have been used to provide strong evidence for tissue-resident mesenchymal cells as cellular contributors to HO. We assess how the underlying mutation in FOP disrupts muscle-specific dynamics during homeostasis and repair, with a focus on muscle-resident mesenchymal cells known as fibro-adipogenic progenitors (FAPs). Accumulating research points to FAPs as a prominent HO progenitor population, with ACVR1R206H FAPs not only aberrantly differentiating into chondro-osteogenic lineages but creating a permissive environment for bone formation at the expense of muscle regeneration. We will further discuss the emerging role of ACVR1R206H FAPs in muscle regeneration and therapeutic targeting of these cells to reduce HO formation in FOP.
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Affiliation(s)
- Loreilys Mejias Rivera
- Cell and Molecular Biology, Genetics and Epigenetics Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 3450 Hamilton Walk, Philadelphia, PA 19104, USA
- Center for Research in FOP and Related Disorders, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eileen M. Shore
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 3450 Hamilton Walk, Philadelphia, PA 19104, USA
- Center for Research in FOP and Related Disorders, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Foteini Mourkioti
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 3450 Hamilton Walk, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Musculoskeletal Program, Penn Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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4
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Gao P, Inada Y, Hotta A, Sakurai H, Ikeya M. iMSC-mediated delivery of ACVR2B-Fc fusion protein reduces heterotopic ossification in a mouse model of fibrodysplasia ossificans progressiva. Stem Cell Res Ther 2024; 15:83. [PMID: 38500216 PMCID: PMC10949803 DOI: 10.1186/s13287-024-03691-7] [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: 09/29/2023] [Accepted: 03/07/2024] [Indexed: 03/20/2024] Open
Abstract
BACKGROUND Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease caused by a gain-of-function mutation in ACVR1, which is a bone morphogenetic protein (BMP) type I receptor. Moreover, it causes progressive heterotopic ossification (HO) in connective tissues. Using FOP patient-derived induced pluripotent stem cells (FOP-iPSCs) and mouse models, we elucidated the underlying mechanisms of FOP pathogenesis and identified a candidate drug for FOP. METHODS In the current study, healthy mesenchymal stem/stromal cells derived from iPSCs (iMSCs) expressing ACVR2B-Fc (iMSCACVR2B-Fc), which is a neutralizing receptobody, were constructed. Furthermore, patient-derived iMSCs and FOP mouse model (ACVR1R206H, female) were used to confirm the inhibitory function of ACVR2B-Fc fusion protein secreted by iMSCACVR2B-Fc on BMP signaling pathways and HO development, respectively. RESULTS We found that secreted ACVR2B-Fc attenuated BMP signaling initiated by Activin-A and BMP-9 in both iMSCs and FOP-iMSCs in vitro. Transplantation of ACVR2B-Fc-expressing iMSCs reduced primary HO in a transgenic mouse model of FOP. Notably, a local injection of ACVR2B-Fc-expressing iMSCs and not an intraperitoneal injection improved the treadmill performance, suggesting compound effects of ACVR2B-Fc and iMSCs. CONCLUSIONS These results offer a new perspective for treating FOP through stem cell therapy.
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Affiliation(s)
- Pan Gao
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases and, Department of General Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, 53, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Yoshiko Inada
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, 53, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Akitsu Hotta
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, 53, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hidetoshi Sakurai
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, 53, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Makoto Ikeya
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, 53, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
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5
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Burdick LN, DelVichio AH, Hanson LR, Griffith BB, Bouchard KR, Hunter JW, Goldhamer DJ. Sex as a Critical Variable in Basic and Pre-Clinical Studies of Fibrodysplasia Ossificans Progressiva. Biomolecules 2024; 14:177. [PMID: 38397414 PMCID: PMC10886767 DOI: 10.3390/biom14020177] [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: 12/23/2023] [Revised: 01/17/2024] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
Heterotopic ossification (HO) is most dramatically manifested in the rare and severely debilitating disease, fibrodysplasia ossificans progressiva (FOP), in which heterotopic bone progressively accumulates in skeletal muscles and associated soft tissues. The great majority of FOP cases are caused by a single amino acid substitution in the type 1 bone morphogenetic protein (BMP) receptor ACVR1, a mutation that imparts responsiveness to activin A. Although it is well-established that biological sex is a critical variable in a range of physiological and disease processes, the impact of sex on HO in animal models of FOP has not been explored. We show that female FOP mice exhibit both significantly greater and more variable HO responses after muscle injury. Additionally, the incidence of spontaneous HO was significantly greater in female mice. This sex dimorphism is not dependent on gonadally derived sex hormones, and reciprocal cell transplantations indicate that apparent differences in osteogenic activity are intrinsic to the sex of the transplanted cells. By circumventing the absolute requirement for activin A using an agonist of mutant ACVR1, we show that the female-specific response to muscle injury or BMP2 implantation is dependent on activin A. These data identify sex as a critical variable in basic and pre-clinical studies of FOP.
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Affiliation(s)
- Lorraine N. Burdick
- Department of Molecular & Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT 06269, USA; (L.N.B.); (A.H.D.); (L.R.H.); (B.B.G.)
| | - Amanda H. DelVichio
- Department of Molecular & Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT 06269, USA; (L.N.B.); (A.H.D.); (L.R.H.); (B.B.G.)
| | - L. Russell Hanson
- Department of Molecular & Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT 06269, USA; (L.N.B.); (A.H.D.); (L.R.H.); (B.B.G.)
| | - Brenden B. Griffith
- Department of Molecular & Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT 06269, USA; (L.N.B.); (A.H.D.); (L.R.H.); (B.B.G.)
| | - Keith R. Bouchard
- Alexion Pharmaceuticals Inc., 100 College Street, New Haven, CT 06510, USA; (K.R.B.); (J.W.H.)
| | - Jeffrey W. Hunter
- Alexion Pharmaceuticals Inc., 100 College Street, New Haven, CT 06510, USA; (K.R.B.); (J.W.H.)
| | - David J. Goldhamer
- Department of Molecular & Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT 06269, USA; (L.N.B.); (A.H.D.); (L.R.H.); (B.B.G.)
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6
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Srinivasan D, Arostegui M, Goebel EJ, Hart KN, Aykul S, Lees-Shepard JB, Idone V, Hatsell SJ, Economides AN. How Activin A Became a Therapeutic Target in Fibrodysplasia Ossificans Progressiva. Biomolecules 2024; 14:101. [PMID: 38254701 PMCID: PMC10813747 DOI: 10.3390/biom14010101] [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: 12/11/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by episodic yet cumulative heterotopic ossification (HO) of skeletal muscles, tendons, ligaments, and fascia. FOP arises from missense mutations in Activin Receptor type I (ACVR1), a type I bone morphogenetic protein (BMP) receptor. Although initial findings implicated constitutive activity of FOP-variant ACVR1 (ACVR1FOP) and/or hyperactivation by BMPs, it was later shown that HO in FOP requires activation of ACVR1FOP by Activin A. Inhibition of Activin A completely prevents HO in FOP mice, indicating that Activin A is an obligate driver of HO in FOP, and excluding a key role for BMPs in this process. This discovery led to the clinical development of garetosmab, an investigational antibody that blocks Activin A. In a phase 2 trial, garetosmab inhibited new heterotopic bone lesion formation in FOP patients. In contrast, antibodies to ACVR1 activate ACVR1FOP and promote HO in FOP mice. Beyond their potential clinical relevance, these findings have enhanced our understanding of FOP's pathophysiology, leading to the identification of fibroadipogenic progenitors as the cells that form HO, and the discovery of non-signaling complexes between Activin A and wild type ACVR1 and their role in tempering HO, and are also starting to inform biological processes beyond FOP.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Aris N. Economides
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA; (D.S.); (M.A.); (E.J.G.); (K.N.H.); (S.A.); (J.B.L.-S.); (V.I.); (S.J.H.)
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7
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Sadeghi Z, Wu YX, Vu A, Song L, Phan W, Kim J, Keast JR, Balis U, DeLancey J, Villalta SA, Zi X. Dysfunction of the aging female mouse urethra is associated with striated muscle loss and increased fibrosis: an initial report. AMERICAN JOURNAL OF CLINICAL AND EXPERIMENTAL UROLOGY 2023; 11:516-529. [PMID: 38148939 PMCID: PMC10749384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 09/29/2023] [Indexed: 12/28/2023]
Abstract
The decline of urethral function with advancing age plays a major role in urinary incontinence in women, impairing quality of life and economically burdening the health care system. However, none of the current urinary incontinence treatments address the declining urethral function with aging, and the mechanisms by which aging impacts urethra physiology remain little known or explored. Here, we have compared functional, morphometric, and global gene expression of urethral tissues between young and old female mice. Bladder leak point pressure (LPP) measurement showed that the aged female mice had 26.55% lower LPP compared to younger mice. Vectorized Scale-Invariant Pattern Recognition (VIPR) analysis of the relative abundance of different tissue components revealed that the mid-urethra of old female mice contains less striated muscle, more extracellular matrix/fibrosis, and diminished elastin fibers ratio compared to young mice. Gene expression profiling analysis (bulk RNA-seq of the whole urethra) showed more down-regulated genes in aged than young mice. Immune response and muscle-related (striated and smooth) pathways were predominantly enriched. In contrast, keratinization, skin development, and cell differentiation pathways were significantly downregulated in aged urethral tissues compared to those from young female mice. These results suggest that molecular pathways (i.e., ACVR1/FST signaling and CTGF/TGF-β signaling) leading to a decreased striated muscle mass and an increase in fibrous extracellular matrix in the process of aging deserve further investigation for their roles in the declined urethral function.
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Affiliation(s)
- Zhina Sadeghi
- Department of Urology, University of CaliforniaIrvine, CA 92868, USA
- Muscle Biology and Disease Research Center, University of CaliforniaIrvine, CA 92868, USA
| | - Yi Xi Wu
- Department of Urology, University of CaliforniaIrvine, CA 92868, USA
| | - Amberly Vu
- Department of Urology, University of CaliforniaIrvine, CA 92868, USA
| | - Liankun Song
- Department of Urology, University of CaliforniaIrvine, CA 92868, USA
| | - William Phan
- Department of Cell Biology and Neuroscience, University of CaliforniaRiverside, CA 92521, USA
| | - Jeffery Kim
- Department of Pathology and Laboratory Medicine, University of CaliforniaIrvine, CA 92868, USA
- Experimental Tissue Resource, University of CaliforniaIrvine, CA 92868, USA
| | - Janet R Keast
- Department of Anatomy and Physiology, University of MelbourneParkville, VIC 3010, Australia
| | - Ulysses Balis
- Department of Pathology-Bioinformatics, University of MichiganAnn Arbor, MI 48109, USA
| | - John DeLancey
- Department of Gynecology, University of MichiganAnn Arbor, MI 48109, USA
| | - S Armando Villalta
- Muscle Biology and Disease Research Center, University of CaliforniaIrvine, CA 92868, USA
- Department of Physiology and Biophysics, University of CaliforniaIrvine, CA 92868, USA
| | - Xiaolin Zi
- Department of Urology, University of CaliforniaIrvine, CA 92868, USA
- Veterans Affairs Long Beach Healthcare SystemLong Beach, CA 90822, USA
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8
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Richardson L, Wilcockson SG, Guglielmi L, Hill CS. Context-dependent TGFβ family signalling in cell fate regulation. Nat Rev Mol Cell Biol 2023; 24:876-894. [PMID: 37596501 DOI: 10.1038/s41580-023-00638-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2023] [Indexed: 08/20/2023]
Abstract
The transforming growth factor-β (TGFβ) family are a large group of evolutionarily conserved cytokines whose signalling modulates cell fate decision-making across varying cellular contexts at different stages of life. Here we discuss new findings in early embryos that reveal how, in contrast to our original understanding of morphogen interpretation, robust cell fate specification can originate from a noisy combination of signalling inputs and a broad range of signalling levels. We compare this evidence with novel findings on the roles of TGFβ family signalling in tissue maintenance and homeostasis during juvenile and adult life, spanning the skeletal, haemopoietic and immune systems. From these comparisons, it emerges that in contrast to robust developing systems, relatively small perturbations in TGFβ family signalling have detrimental effects at later stages in life, leading to aberrant cell fate specification and disease, for example in cancer or congenital disorders. Finally, we highlight novel strategies to target and amend dysfunction in signalling and discuss how gleaning knowledge from different fields of biology can help in the development of therapeutics for aberrant TGFβ family signalling in disease.
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Affiliation(s)
- Louise Richardson
- Developmental Signalling Laboratory, The Francis Crick Institute, London, UK
| | - Scott G Wilcockson
- Developmental Signalling Laboratory, The Francis Crick Institute, London, UK
| | - Luca Guglielmi
- Developmental Signalling Laboratory, The Francis Crick Institute, London, UK
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Caroline S Hill
- Developmental Signalling Laboratory, The Francis Crick Institute, London, UK.
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9
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Allen RS, Jones WD, Hale M, Warder BN, Shore EM, Mullins MC. Reduced GS Domain Serine/Threonine Requirements of Fibrodysplasia Ossificans Progressiva Mutant Type I BMP Receptor ACVR1 in the Zebrafish. J Bone Miner Res 2023; 38:1364-1385. [PMID: 37329499 DOI: 10.1002/jbmr.4869] [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] [Received: 11/30/2022] [Revised: 04/29/2023] [Accepted: 06/14/2023] [Indexed: 06/19/2023]
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare human genetic condition characterized by altered skeletal development and extraskeletal bone formation. All cases of FOP are caused by mutations in the type I bone morphogenetic protein (BMP) receptor gene ACVR1 that result in overactivation of the BMP signaling pathway. Activation of the wild-type ACVR1 kinase requires assembly of a tetrameric type I and II BMP receptor complex followed by phosphorylation of the ACVR1 GS domain by type II BMP receptors. Previous studies showed that the FOP-mutant ACVR1-R206H required type II BMP receptors and presumptive glycine/serine-rich (GS) domain phosphorylation for overactive signaling. Structural modeling of the ACVR1-R206H mutant kinase domain supports the idea that FOP mutations alter the conformation of the GS domain, but it is unclear how this leads to overactive signaling. Here we show, using a developing zebrafish embryo BMP signaling assay, that the FOP-mutant receptors ACVR1-R206H and -G328R have reduced requirements for GS domain phosphorylatable sites to signal compared to wild-type ACVR1. Further, ligand-independent and ligand-dependent signaling through the FOP-mutant ACVR1 receptors have distinct GS domain phosphorylatable site requirements. ACVR1-G328R showed increased GS domain serine/threonine requirements for ligand-independent signaling compared to ACVR1-R206H, whereas it exhibited reduced serine/threonine requirements for ligand-dependent signaling. Remarkably, while ACVR1-R206H does not require the type I BMP receptor partner, Bmpr1, to signal, a ligand-dependent GS domain mutant of ACVR1-R206H could signal independently of Bmpr1 only when Bmp7 ligand was overexpressed. Of note, unlike human ACVR1-R206H, the zebrafish paralog Acvr1l-R203H does not show increased signaling activity. However, in domain-swapping studies, the human kinase domain, but not the human GS domain, was sufficient to confer overactive signaling to the Acvr1l-R203H receptor. Together these results reflect the importance of GS domain activation and kinase domain functions in regulating ACVR1 signaling and identify mechanisms of reduced regulatory constraints conferred by FOP mutations. © 2023 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Robyn S Allen
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
- Department of Orthopaedic Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - William D Jones
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Maya Hale
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Bailey N Warder
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Eileen M Shore
- Department of Orthopaedic Surgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
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10
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Katagiri T, Tsukamoto S, Kuratani M, Tsuji S, Nakamura K, Ohte S, Kawaguchi Y, Takaishi K. A blocking monoclonal antibody reveals dimerization of intracellular domains of ALK2 associated with genetic disorders. Nat Commun 2023; 14:2960. [PMID: 37231012 PMCID: PMC10212922 DOI: 10.1038/s41467-023-38746-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/15/2023] [Indexed: 05/27/2023] Open
Abstract
Mutations in activin receptor-like kinase 2 (ALK2) can cause the pathological osteogenic signaling seen in some patients with fibrodysplasia ossificans progressiva and other conditions such as diffuse intrinsic pontine glioma. Here, we report that intracellular domain of wild-type ALK2 readily dimerizes in response to BMP7 binding to drive osteogenic signaling. This osteogenic signaling is pathologically triggered by heterotetramers of type II receptor kinases and ALK2 mutant forms, which form intracellular domain dimers in response to activin A binding. We develop a blocking monoclonal antibody, Rm0443, that can suppress ALK2 signaling. We solve the crystal structure of the ALK2 extracellular domain complex with a Fab fragment of Rm0443 and show that Rm0443 induces dimerization of ALK2 extracellular domains in a back-to-back orientation on the cell membrane by binding the residues H64 and F63 on opposite faces of the ligand-binding site. Rm0443 could prevent heterotopic ossification in a mouse model of fibrodysplasia ossificans progressiva that carries the human R206H pathogenic mutant.
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Affiliation(s)
- Takenobu Katagiri
- Division of Biomedical Sciences, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama, 350-1241, Japan.
- Project of Clinical and Basic Research for FOP, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama, 350-1241, Japan.
| | - Sho Tsukamoto
- Division of Biomedical Sciences, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama, 350-1241, Japan
- Project of Clinical and Basic Research for FOP, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama, 350-1241, Japan
| | - Mai Kuratani
- Division of Biomedical Sciences, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama, 350-1241, Japan
| | - Shinnosuke Tsuji
- Specialty Medicine Research Laboratories I, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Kensuke Nakamura
- Modality Research Laboratories, Biologics Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Satoshi Ohte
- Division of Biomedical Sciences, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama, 350-1241, Japan
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Yoshiro Kawaguchi
- Modality Research Laboratories, Biologics Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Kiyosumi Takaishi
- Specialty Medicine Research Laboratories I, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
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11
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Yamamoto M, Stoessel SJ, Yamamoto S, Goldhamer DJ. Overexpression of Wild-Type ACVR1 in Fibrodysplasia Ossificans Progressiva Mice Rescues Perinatal Lethality and Inhibits Heterotopic Ossification. J Bone Miner Res 2022; 37:2077-2093. [PMID: 35637634 PMCID: PMC9708949 DOI: 10.1002/jbmr.4617] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/22/2022] [Accepted: 05/28/2022] [Indexed: 11/07/2022]
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a devastating disease of progressive heterotopic bone formation for which effective treatments are currently unavailable. FOP is caused by dominant gain-of-function mutations in the receptor ACVR1 (also known as ALK2), which render the receptor inappropriately responsive to activin ligands. In previous studies, we developed a genetic mouse model of FOP that recapitulates most clinical aspects of the disease. In this model, genetic loss of the wild-type Acvr1 allele profoundly exacerbated heterotopic ossification, suggesting the hypothesis that the stoichiometry of wild-type and mutant receptors dictates disease severity. Here, we tested this model by producing FOP mice that conditionally overexpress human wild-type ACVR1. Injury-induced heterotopic ossification (HO) was completely blocked in FOP mice when expression of both the mutant and wild-type receptor were targeted to Tie2-positive cells, which includes fibro/adipogenic progenitors (FAPs). Perinatal lethality of Acvr1R206H/+ mice was rescued by constitutive ACVR1 overexpression, and these mice survived to adulthood at predicted Mendelian frequencies. Constitutive overexpression of ACVR1 also provided protection from spontaneous abnormal skeletogenesis, and the incidence and severity of injury-induced HO in these mice was dramatically reduced. Analysis of pSMAD1/5/8 signaling both in cultured cells and in vivo indicates that ACVR1 overexpression functions cell-autonomously by reducing osteogenic signaling in response to activin A. We propose that ACVR1 overexpression inhibits HO by decreasing the abundance of ACVR1(R206H)-containing signaling complexes at the cell surface while increasing the representation of activin-A-bound non-signaling complexes comprised of wild-type ACVR1. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Masakazu Yamamoto
- Department of Molecular and Cell BiologyUniversity of Connecticut Stem Cell Institute, University of ConnecticutStorrsCTUSA
| | - Sean J Stoessel
- Department of Molecular and Cell BiologyUniversity of Connecticut Stem Cell Institute, University of ConnecticutStorrsCTUSA
| | - Shoko Yamamoto
- Department of Molecular and Cell BiologyUniversity of Connecticut Stem Cell Institute, University of ConnecticutStorrsCTUSA
| | - David J Goldhamer
- Department of Molecular and Cell BiologyUniversity of Connecticut Stem Cell Institute, University of ConnecticutStorrsCTUSA
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12
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Collins MT. Twists in the fibrodysplasia ossificans progressiva story challenge and expand our understanding of BMP biology. J Clin Invest 2022; 132:160773. [PMID: 35703179 PMCID: PMC9197510 DOI: 10.1172/jci160773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is an ultrarare, debilitating disease in which heterotopic bone is formed in certain soft tissues. A gain-of-function variant in the cytoplasmic domain of the activin A receptor type I (ACVR1) exists in all patients with FOP. Strikingly, these FOP-causing variants imbue a neofunction to ACVR1 — the ability to recognize activin A as an agonist with bone morphogenic protein–like signaling that leads to heterotopic ossification (HO). These findings are supported by the efficacy of anti–activin A antibodies in preventing HO in FOP mice. This surprising story continues in companion papers in this issue of the JCI. Aykul et al. and Lees-Shepard et al. independently found that antibodies against ACVR1, which were being developed as potential therapeutics for FOP, instead caused HO in FOP mice. While this unexpected finding may be the clinical final act for such antibodies, it provides another twist in the unique and evolving FOP story.
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13
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Aykul S, Huang L, Wang L, Das NM, Reisman S, Ray Y, Zhang Q, Rothman NJ, Nannuru KC, Kamat V, Brydges S, Troncone L, Johnsen L, Yu PB, Fazio S, Lees-Shepard J, Schutz K, Murphy AJ, Economides AN, Idone V, Hatsell SJ. ACVR1 antibodies exacerbate heterotopic ossification in fibrodysplasia ossificans progressiva (FOP) by activating FOP-mutant ACVR1. J Clin Invest 2022; 132:153792. [PMID: 35511419 PMCID: PMC9197526 DOI: 10.1172/jci153792] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 04/28/2022] [Indexed: 11/21/2022] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder whose most debilitating pathology is progressive and cumulative heterotopic ossification (HO) of skeletal muscles, ligaments, tendons, and fascia. FOP is caused by mutations in the type I BMP receptor gene ACVR1, which enable ACVR1 to utilize its natural antagonist, activin A, as an agonistic ligand. The physiological relevance of this property is underscored by the fact that HO in FOP is exquisitely dependent on activation of FOP-mutant ACVR1 by activin A, an effect countered by inhibition of anti–activin A via monoclonal antibody treatment. Hence, we surmised that anti-ACVR1 antibodies that block activation of ACVR1 by ligands should also inhibit HO in FOP and provide an additional therapeutic option for this condition. Therefore, we generated anti-ACVR1 monoclonal antibodies that block ACVR1’s activation by its ligands. Surprisingly, in vivo, these anti-ACVR1 antibodies stimulated HO and activated signaling of FOP-mutant ACVR1. This property was restricted to FOP-mutant ACVR1 and resulted from anti-ACVR1 antibody–mediated dimerization of ACVR1. Conversely, wild-type ACVR1 was inhibited by anti-ACVR1 antibodies. These results uncover an additional property of FOP-mutant ACVR1 and indicate that anti-ACVR1 antibodies should not be considered as therapeutics for FOP.
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Affiliation(s)
- Senem Aykul
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Lily Huang
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Lili Wang
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Nanditha M Das
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Sandra Reisman
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Yonaton Ray
- Department of Therapeutic Proteins, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Qian Zhang
- Department of Aging/Age-Related Disorders, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Nyanza J Rothman
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Kalyan C Nannuru
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Vishal Kamat
- Department of Therapeutic Proteins, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Susannah Brydges
- Velocigene, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Luca Troncone
- Department of Medicine, Harvard Medical School, Boston, United States of America
| | - Laura Johnsen
- Research Program Management, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Paul B Yu
- Department of Medicine, Harvard Medical School, Boston, United States of America
| | - Sergio Fazio
- Research Council, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - John Lees-Shepard
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Kevin Schutz
- Antibody Engineering, Adimab, Lebanon, United States of America
| | - Andrew J Murphy
- Regeneron Pharmaceuticals, Inc., Tarryrtown, United States of America
| | - Aris N Economides
- Genome Engineering Technologies, and Skeletal Diseases, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Vincent Idone
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
| | - Sarah J Hatsell
- Skeletal Diseases Therapeutic Focus Area, Regeneron Pharmaceuticals, Inc., Tarrytown, United States of America
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