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Tian F, Dong X, Yuan R, Hou X, Qing J, Li Y. Case Report: Two different acromelic dysplasia phenotypes in a Chinese family caused by a missense mutation in FBN1 and a literature review. Front Pediatr 2024; 12:1428513. [PMID: 39077065 PMCID: PMC11284092 DOI: 10.3389/fped.2024.1428513] [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: 05/06/2024] [Accepted: 07/02/2024] [Indexed: 07/31/2024] Open
Abstract
Background Acromelic dysplasia caused by FBN1 mutation includes acromicric dysplasia (AD), geleophysic dysplasia 2 (GD2), and Weill-Marchesani syndrome 2 (WMS2). All three diseases share severe short stature and brachydactyly. Besides phenotypic similarity, there is a molecular genetic overlap among them, as identical FBN1 gene mutations have been identified in patients with AD, GD2, and WMS2. However, no family with different acromelic dysplasia phenotypes due to the same variant has been described in English reports. Case report The proband presented with typical facial features, severe short stature, short limbs, stubby hands and feet and radiological abnormalities. Her elder sister and mother had similar physical features. In addition, her elder sister was found to have aortic valve stenosis by echocardiography. Mutation analysis demonstrated a heterozygous missense mutation, c.5179C>T (p.Arg1727Trp) in exon 42 of the FBN1. The proband and her mother were diagnosed with AD, and her elder sister with GD2. The proband was treated with recombinant human growth hormone (rhGH) and had a body length gain of 0.72 SDS in half a year. Conclusion These findings expand the phenotypic spectrum of FBN1 gene mutations and highlight that identical FBN1 genotypes can result in different phenotypes of acromelic dysplasia in a family. The efficacy of rhGH therapy in patients with acromelic dysplasia is controversial. More follow-up is needed on the long-term efficacy of rhGH therapy.
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Affiliation(s)
- Fengyan Tian
- Department of Pediatrics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Han D, Wang Z, Chen X, Liu Z, Yang Z, Chen Y, Tian P, Li J, Wang Z. Targeted next-generation sequencing reveals the genetic mechanism of Chinese Marfan syndrome cohort with ocular manifestation. Mol Genet Genomic Med 2024; 12:e2482. [PMID: 38958168 PMCID: PMC11220501 DOI: 10.1002/mgg3.2482] [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: 08/28/2023] [Revised: 05/22/2024] [Accepted: 06/11/2024] [Indexed: 07/04/2024] Open
Abstract
BACKGROUND Marfan syndrome (MFS) is a hereditary connective tissue disorder involving multiple systems, including ophthalmologic abnormalities. Most cases are due to heterozygous mutations in the fibrillin-1 gene (FBN1). Other associated genes include LTBP2, MYH11, MYLK, and SLC2A10. There is significant clinical overlap between MFS and other Marfan-like disorders. PURPOSE To expand the mutation spectrum of FBN1 gene and validate the pathogenicity of Marfan-related genes in patients with MFS and ocular manifestations. METHODS We recruited 318 participants (195 cases, 123 controls), including 59 sporadic cases and 88 families. All patients had comprehensive ophthalmic examinations showing ocular features of MFS and met Ghent criteria. Additionally, 754 cases with other eye diseases were recruited. Panel-based next-generation sequencing (NGS) screened mutations in 792 genes related to inherited eye diseases. RESULTS We detected 181 mutations with an 84.7% detection rate in sporadic cases and 87.5% in familial cases. The overall detection rate was 86.4%, with FBN1 accounting for 74.8%. In cases without FBN1 mutations, 23 mutations from seven Marfan-related genes were identified, including four pathogenic or likely pathogenic mutations in LTBP2. The 181 mutations included 165 missenses, 10 splicings, three frameshifts, and three nonsenses. FBN1 accounted for 53.0% of mutations. The most prevalent pathogenic mutation was FBN1 c.4096G>A. Additionally, 94 novel mutations were detected, with 13 de novo mutations in 14 families. CONCLUSION We expanded the mutation spectrum of the FBN1 gene and provided evidence for the pathogenicity of other Marfan-related genes. Variants in LTBP2 may contribute to the ocular manifestations in MFS, underscoring its role in phenotypic diversity.
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Affiliation(s)
- Dongming Han
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Ziwei Wang
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Xuan Chen
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Zijia Liu
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Zhengtao Yang
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Yixi Chen
- School of Biology and Biological EngineeringSouth China University of TechnologyGuangzhouChina
| | - Peiyi Tian
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Jiankang Li
- City University of Hong Kong Shenzhen Research InstituteShenzhenChina
- He UniversityShenyangChina
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3
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Baban A, Parlapiano G, Cicenia M, Armando M, Franceschini A, Pacifico C, Panfili A, Zinzanella G, Romanzo A, Fusco A, Caiazza M, Perri G, Galletti L, Digilio MC, Buonuomo PS, Bartuli A, Novelli A, Raponi M, Limongelli G. Unique Features of Cardiovascular Involvement and Progression in Children with Marfan Syndrome Justify Dedicated Multidisciplinary Care. J Cardiovasc Dev Dis 2024; 11:114. [PMID: 38667733 PMCID: PMC11050181 DOI: 10.3390/jcdd11040114] [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: 03/01/2024] [Revised: 03/27/2024] [Accepted: 04/01/2024] [Indexed: 04/28/2024] Open
Abstract
Marfan syndrome (MIM: # 154700; MFS) is an autosomal dominant disease representing the most common form of heritable connective tissue disorder. The condition presents variable multiorgan expression, typically involving a triad of cardiovascular, eye, and skeletal manifestations. Other multisystemic features are often underdiagnosed. Moreover, the disease is characterized by age related penetrance. Diagnosis and management of MFS in the adult population are well-described in literature. Few studies are focused on MFS in the pediatric population, making the clinical approach (cardiac and multiorgan) to these cases challenging both in terms of diagnosis and serial follow-up. In this review, we provide an overview of MFS manifestations in children, with extensive revision of major organ involvement (cardiovascular ocular and skeletal). We attempt to shed light on minor aspects of MFS that can have a significant progressive impact on the health of affected children. MFS is an example of a syndrome where an early personalized approach to address a dynamic, genetically determined condition can make a difference in outcome. Applying an early multidisciplinary clinical approach to MFS cases can prevent acute and chronic complications, offer tailored management, and improve the quality of life of patients.
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Affiliation(s)
- Anwar Baban
- The European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart, Cardiogenetic Center, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 00165 Rome, Italy; (G.P.); (A.P.)
| | - Giovanni Parlapiano
- The European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart, Cardiogenetic Center, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 00165 Rome, Italy; (G.P.); (A.P.)
| | - Marianna Cicenia
- The European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart, Pediatric Cardiology and Arrhythmia/Syncope Units, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (M.C.); (A.F.)
| | - Michela Armando
- Department of Neuroscience and Neurorehabilitation, Bambino Gesù Children’s Hospital, IRCCS, 00168 Rome, Italy;
| | - Alessio Franceschini
- The European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart, Pediatric Cardiology and Arrhythmia/Syncope Units, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (M.C.); (A.F.)
| | - Concettina Pacifico
- Audiology and Otosurgery Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
| | - Arianna Panfili
- The European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart, Cardiogenetic Center, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 00165 Rome, Italy; (G.P.); (A.P.)
| | - Gaetano Zinzanella
- Ophthalmology Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (G.Z.); (A.R.)
| | - Antonino Romanzo
- Ophthalmology Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (G.Z.); (A.R.)
| | - Adelaide Fusco
- Inherited and Rare Cardiovascular Diseases, Department of Translational Medical Sciences, University of Campania “Luigi Vanvitelli”, Monaldi Hospital, 80131 Naples, Italy; (A.F.); (M.C.); (G.L.)
| | - Martina Caiazza
- Inherited and Rare Cardiovascular Diseases, Department of Translational Medical Sciences, University of Campania “Luigi Vanvitelli”, Monaldi Hospital, 80131 Naples, Italy; (A.F.); (M.C.); (G.L.)
| | - Gianluigi Perri
- Department of Pediatric Cardiology and Cardiac Surgery, Heart and Lung Transplant, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (G.P.); (L.G.)
| | - Lorenzo Galletti
- Department of Pediatric Cardiology and Cardiac Surgery, Heart and Lung Transplant, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (G.P.); (L.G.)
| | - Maria Cristina Digilio
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (M.C.D.); (P.S.B.); (A.B.)
| | - Paola Sabrina Buonuomo
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (M.C.D.); (P.S.B.); (A.B.)
| | - Andrea Bartuli
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (M.C.D.); (P.S.B.); (A.B.)
| | - Antonio Novelli
- Translational Cytogenomics Research Unit, Laboratory of Medical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy;
| | - Massimiliano Raponi
- Medical Direction, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
| | - Giuseppe Limongelli
- Inherited and Rare Cardiovascular Diseases, Department of Translational Medical Sciences, University of Campania “Luigi Vanvitelli”, Monaldi Hospital, 80131 Naples, Italy; (A.F.); (M.C.); (G.L.)
- Centre for Paediatric Inherited and Rare Cardiovascular Disease, Institute of Cardiovascular Science, University College London, London WC1N 3JH, UK
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Seeburun S, Wu S, Hemani D, Pham L, Ju D, Xie Y, Kata P, Li L. Insights into elastic fiber fragmentation: Mechanisms and treatment of aortic aneurysm in Marfan syndrome. Vascul Pharmacol 2023; 153:107215. [PMID: 37640090 PMCID: PMC10872825 DOI: 10.1016/j.vph.2023.107215] [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: 08/06/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in fibrillin 1 (FBN1) gene. These mutations result in defects in the skeletal, ocular, and cardiovascular systems. Aortic aneurysm is the leading cause of premature mortality in untreated MFS patients. Elastic fiber fragmentation in the aortic vessel wall is a hallmark of MFS-associated aortic aneurysms. FBN1 mutations result in FBN1 fragments that also contribute to elastic fiber fragmentation. Although recent research has advanced our understanding of MFS, the contribution of elastic fiber fragmentation to the pathogenesis of aneurysm formation remains poorly understood. This review provides a comprehensive overview of the molecular mechanisms of elastic fiber fragmentation and its role in the pathogenesis of aortic aneurysm progression. Increased comprehension of elastic fragmentation has significant clinical implications for developing targeted interventions to block aneurysm progression, which would benefit not only individuals with Marfan syndrome but also other patients with aneurysms. Moreover, this review highlights an overlooked connection between inhibiting aneurysm and the restoration of elastic fibers in the vessel wall with various aneurysm inhibitors, including drugs and chemicals. Investigating the underlying molecular mechanisms could uncover innovative therapeutic strategies to inhibit elastin fragmentation and prevent the progression of aneurysms.
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Affiliation(s)
- Sheilabi Seeburun
- Department of Internal Medicine, Wayne State University, Detroit MI, USA
| | - Shichao Wu
- Department of Internal Medicine, Wayne State University, Detroit MI, USA
| | - Darshi Hemani
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit MI, USA
| | - Lucynda Pham
- Department of Internal Medicine, Wayne State University, Detroit MI, USA
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit MI, USA
| | - Donghong Ju
- Department of Internal Medicine, Wayne State University, Detroit MI, USA
- Department of Oncology, Wayne State University, Detroit MI, USA
| | - Youming Xie
- Department of Oncology, Wayne State University, Detroit MI, USA
| | - Priyaranjan Kata
- Department of Internal Medicine, Wayne State University, Detroit MI, USA
| | - Li Li
- Department of Internal Medicine, Wayne State University, Detroit MI, USA
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit MI, USA
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5
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Saxton S, Dickinson G, Wang D, Zhou B, Um SY, Lin Y, Rojas L, Sampson BA, Graham JK, Tang Y. Molecular Genetic Characterization of Sudden Deaths Due to Thoracic Aortic Dissection or Rupture. Cardiovasc Pathol 2023; 65:107540. [PMID: 37116669 DOI: 10.1016/j.carpath.2023.107540] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/07/2023] [Accepted: 04/23/2023] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Sudden deaths due to thoracic aortic dissection or ruptures (TADR) are often investigated by forensic pathologists in the United States. Up to a quarter of reported TADR result from a highly penetrant autosomal dominant single gene variant. Testing genes associated with familial TADR provides an underlying etiology for the cause of death and informs effective sudden death prevention for at-risk family members. At the New York City Office of Chief Medical Examiner (NYC-OCME), TADR cases are routinely tested by the in-house, CAP-accredited Molecular Genetics Laboratory. In this retrospective study, TADR and cardiovascular cases were reviewed to understand the burden of TADR in sudden deaths, value of molecular diagnostic testing in TADR, and genotype-phenotype correlations in a demographically diverse TADR cohort. METHODS Between July 2019 and June 2022, cases with in-house cardiovascular genetic testing at NYC-OCME were retrospectively reviewed. Twenty genes associated with familial TADR were analyzed using high throughput massive parallel sequencing on postmortem tissues or bloodspot cards. Variant interpretation was conducted according to ACMG/AMP guidelines. RESULTS A total of 1078 cases were tested for cardiovascular genetic conditions, of which 34 (3%) had TADR. Eight of those TADR cases had a pathogenic or likely pathogenic variant (P/LPV), 4 had a variant of uncertain significance (VUS), and 22 cases were negative for variants in TADR genes. The molecular diagnostic yield using the TADR subpanel was 23.5%. The genes with the greatest prevalence of P/LPV were FBN1 (6), followed by TGFBR2 (2), TGFBR1 (1), and MYLK (1). Highly penetrant P/LPV in TGFBR2, FBN1, and TGFBR1 were found in TADR individuals who died younger than 34 years old. Two P/LPV in FBN1 were secondary findings unrelated to cause of death. P/LPV in FBN1 included five truncating variants located in the N-terminal domains and one missense variant involved in the disulfide bonds of the EGF-like domain. All P/LPV in TGFBR1 and TGFBR2 were missense or in-frame deletion variants located in the protein kinase catalytic domain. Three variants were first reported in this study. CONCLUSIONS Molecular testing of familial TADR-associated genes is a highly effective tool to identify the genetic cause of TADR sudden deaths and benefits surviving at-risk families.
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Affiliation(s)
| | - Gregory Dickinson
- Department of Forensic Pathology, New York City Office of Chief Medical Examiner
| | | | - Bo Zhou
- Molecular Genetics Laboratory
| | | | | | | | - Barbara A Sampson
- Department of Forensic Pathology, New York City Office of Chief Medical Examiner
| | - Jason K Graham
- Department of Forensic Pathology, New York City Office of Chief Medical Examiner
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6
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Godwin ARF, Dajani R, Zhang X, Thomson J, Holmes DF, Adamo CS, Sengle G, Sherratt MJ, Roseman AM, Baldock C. Fibrillin microfibril structure identifies long-range effects of inherited pathogenic mutations affecting a key regulatory latent TGFβ-binding site. Nat Struct Mol Biol 2023; 30:608-618. [PMID: 37081316 DOI: 10.1038/s41594-023-00950-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/28/2023] [Indexed: 04/22/2023]
Abstract
Genetic mutations in fibrillin microfibrils cause serious inherited diseases, such as Marfan syndrome and Weill-Marchesani syndrome (WMS). These diseases typically show major dysregulation of tissue development and growth, particularly in skeletal long bones, but links between the mutations and the diseases are unknown. Here we describe a detailed structural analysis of native fibrillin microfibrils from mammalian tissue by cryogenic electron microscopy. The major bead region showed pseudo eightfold symmetry where the amino and carboxy termini reside. On the basis of this structure, we show that a WMS deletion mutation leads to the induction of a structural rearrangement that blocks interaction with latent TGFβ-binding protein-1 at a remote site. Separate deletion of this binding site resulted in the assembly of shorter fibrillin microfibrils with structural alterations. The integrin αvβ3-binding site was also mapped onto the microfibril structure. These results establish that in complex extracellular assemblies, such as fibrillin microfibrils, mutations may have long-range structural consequences leading to the disruption of growth factor signaling and the development of disease.
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Affiliation(s)
- Alan R F Godwin
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Rana Dajani
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Xinyang Zhang
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Jennifer Thomson
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - David F Holmes
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Christin S Adamo
- Center for Biochemistry, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Department of Pediatrics and Adolescent Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Gerhard Sengle
- Center for Biochemistry, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Department of Pediatrics and Adolescent Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Center for Musculoskeletal Biomechanics, Cologne, Germany
| | - Michael J Sherratt
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Alan M Roseman
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Clair Baldock
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
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Quitter F, Flury M, Waldmueller S, Schubert T, Koehler K, Huebner A. Acromicric dysplasia due to a novel missense mutation in the fibrillin 1 gene in a three-generation family. J Pediatr Endocrinol Metab 2022; 35:1443-1447. [PMID: 35942587 DOI: 10.1515/jpem-2022-0287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/10/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Short stature is one of the most common reasons for consulting a paediatric endocrinologist. Targeted diagnosis of familial short stature can be challenging due to a broad spectrum of differential diagnoses. CASE PRESENTATION Here we report a novel mutation in the fibrillin 1 gene (FBN1) in six family members causing a mild phenotype of acromicric dysplasia. Additionally, we present the effects of growth hormone therapy in one of the affected children. CONCLUSIONS Acromicric dysplasia is a very rare skeletal dysplasia with a prevalence of <1 of 1.000.000 with only about 60 cases being reported worldwide. It is characterized by short stature, acromelia, mild facial dysmorphy but normal intelligence. This study aims to exemplify the clinical and molecular features of FBN1-related acromicric dysplasia and illustrates its pleiotropy by presenting a new, mild phenotype.
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Affiliation(s)
- Friederike Quitter
- Children's Hospital, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Monika Flury
- Children's Hospital, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Stephan Waldmueller
- University Hospital Tübingen, Institut für Medizinische Genetik und Angewandte Genomik Tübingen, Germany
| | - Tina Schubert
- Children's Hospital, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Katrin Koehler
- Children's Hospital, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Angela Huebner
- Children's Hospital, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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8
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Zhang X, Alanazi YF, Jowitt TA, Roseman AM, Baldock C. Elastic Fibre Proteins in Elastogenesis and Wound Healing. Int J Mol Sci 2022; 23:4087. [PMID: 35456902 PMCID: PMC9027394 DOI: 10.3390/ijms23084087] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/31/2022] [Accepted: 04/03/2022] [Indexed: 12/30/2022] Open
Abstract
As essential components of our connective tissues, elastic fibres give tissues such as major blood vessels, skin and the lungs their elasticity. Their formation is complex and co-ordinately regulated by multiple factors. In this review, we describe key players in elastogenesis: fibrillin-1, tropoelastin, latent TGFβ binding protein-4, and fibulin-4 and -5. We summarise their roles in elastogenesis, discuss the effect of their mutations on relevant diseases, and describe their interactions involved in forming the elastic fibre network. Moreover, we look into their roles in wound repair for a better understanding of their potential application in tissue regeneration.
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Affiliation(s)
- Xinyang Zhang
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK; (X.Z.); (T.A.J.)
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK;
| | - Yasmene F. Alanazi
- Department of Biochemistry, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia;
| | - Thomas A. Jowitt
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK; (X.Z.); (T.A.J.)
| | - Alan M. Roseman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK;
| | - Clair Baldock
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK; (X.Z.); (T.A.J.)
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK;
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9
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Singh M, Becker M, Godwin AR, Baldock C. Structural studies of elastic fibre and microfibrillar proteins. Matrix Biol Plus 2021; 12:100078. [PMID: 34355160 PMCID: PMC8322146 DOI: 10.1016/j.mbplus.2021.100078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 11/27/2022] Open
Abstract
Elastic tissues owe their functional properties to the composition of their extracellular matrices, particularly the range of extracellular, multidomain extensible elastic fibre and microfibrillar proteins. These proteins include elastin, fibrillin, latent TGFβ binding proteins (LTBPs) and collagens, where their biophysical and biochemical properties not only give the matrix structural integrity, but also play a vital role in the mechanisms that underlie tissue homeostasis. Thus far structural information regarding the structure and hierarchical assembly of these molecules has been challenging and the resolution has been limited due to post-translational modification and their multidomain nature leading to flexibility, which together result in conformational and structural heterogeneity. In this review, we describe some of the matrix proteins found in elastic fibres and the new emerging techniques that can shed light on their structure and dynamic properties.
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Affiliation(s)
- Mukti Singh
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Mark Becker
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Alan R.F. Godwin
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Clair Baldock
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
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10
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Tehrani AY, Ciufolini MA, Bernatchez P. Nitric oxide in the Marfan vasculature: Friend or foe? Nitric Oxide 2021; 116:27-34. [PMID: 34478846 DOI: 10.1016/j.niox.2021.08.006] [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: 07/04/2021] [Revised: 08/13/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the FBN1 gene, which encodes fibrillin-1, a protein essential for the formation and stabilization of elastic fibers as well as signaling homeostasis. Progressive aortic root widening is the most serious manifestation of MFS as it can lead to aortic dissection, aneurysm formation and rupture. However, despite their ability to decrease the hemodynamic stress the aorta is subjected to, anti-hypertensive medications often lead to underwhelming reductions in the rate of aortic root dilation, which illustrates how fragmental our understanding of MFS-associated aortic remodeling is. This manuscript summarizes recent evidence that document nitric oxide (NO) synthase (NOS)-related changes to the vasculature during the pathogenesis of MFS and how they result in a unique state of vascular dysfunction that likely plays a causal role in the aortic root widening process. We also review how clinic-approved and experimental therapies as well lifestyle approaches may promote aortic root stability by correcting NO homeostasis, which if properly optimized may improve outcomes in this population afflicted by a notoriously refractory type of aortopathy.
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Affiliation(s)
- Arash Y Tehrani
- Centre for Heart + Lung Innovation, St. Paul's Hospital, Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia (UBC), Vancouver, Canada
| | | | - Pascal Bernatchez
- Centre for Heart + Lung Innovation, St. Paul's Hospital, Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia (UBC), Vancouver, Canada.
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11
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Shan YC, Yang ZC, Ma L, Ran N, Feng XY, Liu XM, Fu P, Yi MJ. A Review of Three Chinese Cases of Acromicric/Geleophysic Dysplasia with FBN1 Mutations. Int J Gen Med 2021; 14:1873-1880. [PMID: 34040419 PMCID: PMC8139683 DOI: 10.2147/ijgm.s306018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/14/2021] [Indexed: 12/02/2022] Open
Abstract
Objective This study aims to explore the clinical features and molecular diagnosis of FBN1-related acromelic dysplasia in Chinese patients. Methods The clinical and genetic features of three FBN1-related acromicric dysplasia (AD)/geleophysic dysplasia (GD) Chinese patients from two families were reviewed, and comprehensive medical evaluations were performed. Targeted next-generation sequencing was used to detect genetic mutations associated with short statures, including FBN1. Sanger sequencing was used to determine the de novo mutation origin. Results Patient 1 presented with short stature, short and stubby hands and feet, mild facial dysmorphism, hepatomegaly, delayed bone age and beak-like femoral heads. Patient 2 and this patient’s father merely presented with short stature, wide and short hands, and beak-like femoral heads. One novel mutation, c.5272G>T(p.D1758Y), and one known mutation, c.5183C>T(p.A1728V), were identified in these patients. Conclusion The clinical features varied among these patients. The variant c.5272G>T(p.D1758Y) is a novel mutation.
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Affiliation(s)
- Yan-Chun Shan
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Zhao-Chuan Yang
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Liang Ma
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Ni Ran
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Xue-Ying Feng
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Xiao-Mei Liu
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Peng Fu
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Ming-Ji Yi
- Department of Child Health Care, Pediatric Center, Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
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12
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Cale JM, Greer K, Fletcher S, Wilton SD. Proof-of-Concept: Antisense Oligonucleotide Mediated Skipping of Fibrillin-1 Exon 52. Int J Mol Sci 2021; 22:ijms22073479. [PMID: 33801742 PMCID: PMC8037683 DOI: 10.3390/ijms22073479] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/16/2022] Open
Abstract
Marfan syndrome is one of the most common dominantly inherited connective tissue disorders, affecting 2–3 in 10,000 individuals, and is caused by one of over 2800 unique FBN1 mutations. Mutations in FBN1 result in reduced fibrillin-1 expression, or the production of two different fibrillin-1 monomers unable to interact to form functional microfibrils. Here, we describe in vitro evaluation of antisense oligonucleotides designed to mediate exclusion of FBN1 exon 52 during pre-mRNA splicing to restore monomer homology. Antisense oligonucleotide sequences were screened in healthy control fibroblasts. The most effective sequence was synthesised as a phosphorodiamidate morpholino oligomer, a chemistry shown to be safe and effective clinically. We show that exon 52 can be excluded in up to 100% of FBN1 transcripts in healthy control fibroblasts transfected with PMO52. Immunofluorescent staining revealed the loss of fibrillin 1 fibres with ~50% skipping and the subsequent re-appearance of fibres with >80% skipping. However, the effect of exon skipping on the function of the induced fibrillin-1 isoform remains to be explored. Therefore, these findings demonstrate proof-of-concept that exclusion of an exon from FBN1 pre-mRNA can result in internally truncated but identical monomers capable of forming fibres and lay a foundation for further investigation to determine the effect of exon skipping on fibrillin-1 function.
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Affiliation(s)
- Jessica M. Cale
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
| | - Kane Greer
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Nedlands, WA 6009, Australia
- PYC Therapeutics, Nedlands, WA 6009, Australia
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Nedlands, WA 6009, Australia
- Correspondence: ; Tel.: +61-8-9360-2305
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13
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Jensen SA, Atwa O, Handford PA. Assembly assay identifies a critical region of human fibrillin-1 required for 10-12 nm diameter microfibril biogenesis. PLoS One 2021; 16:e0248532. [PMID: 33735269 PMCID: PMC7971562 DOI: 10.1371/journal.pone.0248532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/26/2021] [Indexed: 11/17/2022] Open
Abstract
The human FBN1 gene encodes fibrillin-1 (FBN1); the main component of the 10–12 nm diameter extracellular matrix microfibrils. Marfan syndrome (MFS) is a common inherited connective tissue disorder, caused by FBN1 mutations. It features a wide spectrum of disease severity, from mild cases to the lethal neonatal form (nMFS), that is yet to be explained at the molecular level. Mutations associated with nMFS generally affect a region of FBN1 between domains TB3-cbEGF18—the "neonatal region". To gain insight into the process of fibril assembly and increase our understanding of the mechanisms determining disease severity in MFS, we compared the secretion and assembly properties of FBN1 variants containing nMFS-associated substitutions with variants associated with milder, classical MFS (cMFS). In the majority of cases, both nMFS- and cMFS-associated neonatal region variants were secreted at levels comparable to wild type. Microfibril incorporation by the nMFS variants was greatly reduced or absent compared to the cMFS forms, however, suggesting that nMFS substitutions disrupt a previously undefined site of microfibril assembly. Additional analysis of a domain deletion variant caused by exon skipping also indicates that register in the neonatal region is likely to be critical for assembly. These data demonstrate for the first time new requirements for microfibril biogenesis and identify at least two distinct molecular mechanisms associated with disease substitutions in the TB3-cbEGF18 region; incorporation of mutant FBN1 into microfibrils changing their integral properties (cMFS) or the blocking of wild type FBN1 assembly by mutant molecules that prevents late-stage lateral assembly (nMFS).
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Affiliation(s)
- Sacha A Jensen
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Ondine Atwa
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Penny A Handford
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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14
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Sun C, Xu D, Pei Z, Yang L, Qiao Z, Lu W, Luo F, Qiu Z. Separation in genetic pathogenesis of mutations in FBN1-TB5 region between autosomal dominant acromelic dysplasia and Marfan syndrome. Birth Defects Res 2020; 112:1834-1842. [PMID: 33030311 DOI: 10.1002/bdr2.1814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/16/2020] [Accepted: 09/21/2020] [Indexed: 11/07/2022]
Abstract
Mutations in the transforming growth factor β-binding protein-like domain 5 (TB5) region of FBN1 can lead to autosomal acromelic dysplasia and Marfan syndrome, which are two diseases with apparently opposite phenotypes. We identified six patients with acromelic dysplasia carrying either the previously reported mutations c.5284G > A (p.Gly1762Ser) and c.5096A > G (p.Tyr1699Cys) or the novel mutation c.5260G > A (p.Gly1754Ser). A systematic review of patients with mutations in the FBN1-TB5 region showed that acromelic dysplasia is caused only by in-frame amino acid substitutions. In contrast, truncating mutations in the FBN1-TB5 have been reported only in Marfan syndrome. Acromelic dysplasia subtypes that share symptoms with Marfan syndrome are associated with FBN1-TB5 disulfide disruptions, which are also commonly found in Marfan syndrome. These results suggest that the type and location of mutations in the FBN1-TB5 region determine the clinical spectrum of fibrillinopathy.
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Affiliation(s)
- Chengjun Sun
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Dandan Xu
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Zhou Pei
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Lin Yang
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China.,The Molecular Genetic Diagnosis Center, Pediatrics Research Institute, Children's Hospital of Fudan University, Shanghai, China
| | - Zhongwei Qiao
- Department of Radiology, Children's Hospital of Fudan University, Shanghai, China
| | - Wei Lu
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Feihong Luo
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Zhengqing Qiu
- Department of Pediatrics, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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15
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Li M, Lu X, Dong J, Yao Z, Wu Y, Rao H, Huang X, Chen X, Huang Y, Wu Y. A synonymous mutation in exon 39 of FBN1 causes exon skipping leading to Marfan syndrome. Genomics 2020; 112:3856-3861. [PMID: 32562828 DOI: 10.1016/j.ygeno.2020.06.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/13/2020] [Accepted: 06/15/2020] [Indexed: 11/15/2022]
Abstract
Marfan syndrome is a heritable autosomal-dominant connective tissue disorder and it was typically caused by mutations in FBN1. However, the synonymous mutation was seldom recorded to be related to Marfan syndrome. Hereon, Multiplex ligation-dependent probe amplification failed to detect a copy number variant involving FBN1 but a synonymous mutation c.4773A > G (p.Gly1591Gly) was identified by NGS in exon 39. RNA was extracted from patient's aortic tissue and reverse polymerase chain reaction demonstrated the presence of a shortened mRNA transcript. Results of minigene models indicated that c.4773A > G was bona fide responsibility for the aberrant splicing pattern, and artificial mutations of c.4773A > C and c.4773A > T also gave rise to fragments with exon 39 entire skipped. Together, the novel synonymous mutations in c.4773 position (A > G, C, T), middle of exon 39 of FBN1 gene, was found to be associated with Marfan syndrome by altering the splicing pattern of pre-mRNA.
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Affiliation(s)
- Mingjie Li
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Xinxin Lu
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Jian Dong
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Zuwu Yao
- Department of Cardiovascular Surgery, Fujian Provincial Hospital, Fuzhou 350001, China
| | - Yinlong Wu
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Huiying Rao
- Department of Ophthalmology, Fujian Provincial Hospital, Fuzhou 350001, China
| | - Xiaoli Huang
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Xijun Chen
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Yi Huang
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China
| | - Yan'an Wu
- Department of Clinical Laboratory, Fujian Provincial Hospital, Shengli Clinical Medical College, Fujian Medical University, Fuzhou 350001, China.
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16
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Fibrillin-1 and fibrillin-1-derived asprosin in adipose tissue function and metabolic disorders. J Cell Commun Signal 2020; 14:159-173. [PMID: 32279186 DOI: 10.1007/s12079-020-00566-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/28/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
The extracellular matrix microenvironment of adipose tissue is of critical importance for the differentiation, remodeling and function of adipocytes. Fibrillin-1 is one of the main components of microfibrils and a key player in this process. Furin processing of profibrillin-1 results in mature fibrillin-1 and releases the C-terminal propeptide as a circulating hunger hormone, asprosin. Mutations in the fibrillin-1 gene lead to adipose tissue dysfunction and causes Marfan syndrome, marfanoid progeroid lipodystrophy syndrome, and neonatal progeroid syndrome. Increased TGF-β signaling, altered mechanical properties and impaired adipogenesis are potential causes of adipose tissue dysfunction, mediated through deficient microfibrils. Circulating asprosin on the other hand is secreted primarily by white adipose tissue under fasting conditions and in obesity. It increases hepatic glucose production and drives insulin secretion and appetite stimulation through inter-organ cross talk. This review discusses the metabolic consequences of fibrillin-1 and fibrillin-1-derived asprosin in pathological conditions. Understanding the dynamic role of fibrillin-1 in the adipose tissue milieu and of circulating asprosin in the body can provide novel mechanistic insights into how fibrillin-1 may contribute to metabolic syndrome. This could lead to new management regimens of patients with metabolic disease.
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17
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Role of fibrillin-2 in the control of TGF-β activation in tumor angiogenesis and connective tissue disorders. Biochim Biophys Acta Rev Cancer 2020; 1873:188354. [PMID: 32119940 DOI: 10.1016/j.bbcan.2020.188354] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 01/01/2023]
Abstract
Fibrillins constitute a family of large extracellular glycoproteins which multimerize to form microfibrils, an important structure in the extracellular matrix. It has long been assumed that fibrillin-2 was barely present during postnatal life, but it is now clear that fibrillin-2 molecules form the structural core of microfibrils, and are masked by an outer layer of fibrillin-1. Mutations in fibrillins give rise to heritable connective tissue disorders, including Marfan syndrome and congenital contractural arachnodactyly. Fibrillins also play an important role in matrix sequestering of members of the transforming growth factor-β family, and in context of Marfan syndrome excessive TGF-β activation has been observed. TGF-β activation is highly dependent on integrin binding, including integrin αvβ8 and αvβ6, which are upregulated upon TGF-β exposure. TGF-β is also involved in tumor progression, metastasis, epithelial-to-mesenchymal transition and tumor angiogenesis. In several highly vascularized types of cancer such as hepatocellular carcinoma, a positive correlation was found between increased TGF-β plasma concentrations and tumor vascularity. Interestingly, fibrillin-1 has a higher affinity to TGF-β and, therefore, has a higher capacity to sequester TGF-β compared to fibrillin-2. The previously reported downregulation of fibrillin-1 in tumor endothelium affects the fibrillin-1/fibrillin-2 ratio in the microfibrils, exposing the normally hidden fibrillin-2. We postulate that fibrillin-2 exposure in the tumor endothelium directly stimulates tumor angiogenesis by influencing TGF-β sequestering by microfibrils, leading to a locally higher active TGF-β concentration in the tumor microenvironment. From a therapeutic perspective, fibrillin-2 might serve as a potential target for future anti-cancer therapies.
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18
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Godwin ARF, Singh M, Lockhart-Cairns MP, Alanazi YF, Cain SA, Baldock C. The role of fibrillin and microfibril binding proteins in elastin and elastic fibre assembly. Matrix Biol 2019; 84:17-30. [PMID: 31226403 PMCID: PMC6943813 DOI: 10.1016/j.matbio.2019.06.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/16/2019] [Accepted: 06/17/2019] [Indexed: 12/17/2022]
Abstract
Fibrillin is a large evolutionarily ancient extracellular glycoprotein that assembles to form beaded microfibrils which are essential components of most extracellular matrices. Fibrillin microfibrils have specific biomechanical properties to endow animal tissues with limited elasticity, a fundamental feature of the durable function of large blood vessels, skin and lungs. They also form a template for elastin deposition and provide a platform for microfibril-elastin binding proteins to interact in elastic fibre assembly. In addition to their structural role, fibrillin microfibrils mediate cell signalling via integrin and syndecan receptors, and microfibrils sequester transforming growth factor (TGF)β family growth factors within the matrix to provide a tissue store which is critical for homeostasis and remodelling.
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Affiliation(s)
- Alan R F Godwin
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Mukti Singh
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Michael P Lockhart-Cairns
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Yasmene F Alanazi
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK
| | - Stuart A Cain
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK.
| | - Clair Baldock
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK.
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19
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Del Cid JS, Reed NI, Molnar K, Liu S, Dang B, Jensen SA, DeGrado W, Handford PA, Sheppard D, Sundaram AB. A disease-associated mutation in fibrillin-1 differentially regulates integrin-mediated cell adhesion. J Biol Chem 2019; 294:18232-18243. [PMID: 31640988 DOI: 10.1074/jbc.ra119.011109] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/14/2019] [Indexed: 11/06/2022] Open
Abstract
Fibrillins serve as scaffolds for the assembly of elastic fibers that contribute to the maintenance of tissue homeostasis and regulate growth factor signaling in the extracellular space. Fibrillin-1 is a modular glycoprotein that includes 7 latent transforming growth factor β (TGFβ)-binding protein-like (TB) domains and mediates cell adhesion through integrin binding to the RGD motif in its 4th TB domain. A subset of missense mutations within TB4 cause stiff skin syndrome (SSS), a rare autosomal dominant form of scleroderma. The fibrotic phenotype is thought to be regulated by changes in the ability of fibrillin-1 to mediate integrin binding. We characterized the ability of each RGD-binding integrin to mediate cell adhesion to fibrillin-1 or a disease-causing variant. Our data show that 7 of the 8 RGD-binding integrins can mediate adhesion to fibrillin-1. A single amino acid substitution responsible for SSS (W1570C) markedly inhibited adhesion mediated by integrins α5β1, αvβ5, and αvβ6, partially inhibited adhesion mediated by αvβ1, and did not inhibit adhesion mediated by α8β1 or αIIbβ3. Adhesion mediated by integrin αvβ3 depended on the cell surface expression level. In the SSS mutant background, the presence of a cysteine residue in place of highly conserved tryptophan 1570 alters the conformation of the region containing the exposed RGD sequence within the same domain to differentially affect fibrillin's interactions with distinct RGD-binding integrins.
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Affiliation(s)
- Joselyn S Del Cid
- Department of Cell Biology, University of California San Francisco, San Francisco, California 94158
| | - Nilgun Isik Reed
- Department of Cell Biology, University of California San Francisco, San Francisco, California 94158
| | - Kathleen Molnar
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94518
| | - Sean Liu
- Department of Cell Biology, University of California San Francisco, San Francisco, California 94158
| | - Bobo Dang
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94518
| | - Sacha A Jensen
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - William DeGrado
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94518
| | - Penny A Handford
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Dean Sheppard
- Department of Cell Biology, University of California San Francisco, San Francisco, California 94158
| | - Aparna B Sundaram
- Department of Cell Biology, University of California San Francisco, San Francisco, California 94158.
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20
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Baudhuin LM, Kluge ML, Kotzer KE, Lagerstedt SA. Variability in gene-based knowledge impacts variant classification: an analysis of FBN1 missense variants in ClinVar. Eur J Hum Genet 2019; 27:1550-1560. [PMID: 31227806 DOI: 10.1038/s41431-019-0440-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 05/13/2019] [Accepted: 05/21/2019] [Indexed: 01/07/2023] Open
Abstract
Gene-specific knowledge can enhance genetic variant classification, but may not be routinely incorporated into clinical laboratory practice. For example, FBN1 variants associated with Marfan syndrome may be variably classified depending on knowledge of FBN1-specific critical regions. In order to assess variability in classification of FBN1 variants, 674 FBN1 missense variants from 18 ClinVar submitters were compared and reanalyzed using FBN1-specific criteria and ACMG/AMP 2015 guidelines for variant interpretation. Conflicting variant classifications occurred in 30.7% of the missense variants that had multiple submitters. There were 451 classifications of 361 critical residue missense variants, with 80.0% (361/451) classified as likely pathogenic or pathogenic [(L)P]. Non-cysteine critical residue variants were less likely to be classified as (L)P [55.3% (78/141)] than cysteine variants [91.3% (283/310)] and were more likely to lack evidence citing the functional significance of the amino acid impacted. Application of FBN1-specific knowledge allowed for reclassification or discrepancy resolution in 65/361 (18.0%) critical residue variants. There were 522 classifications of 313 unique missense variants not known to impact a critical residue. Of these, 31.6% (165/522) were likely overclassified as either (L)P or uncertain significance (VUS), especially when minor allele frequency (MAF) was taken into account, and we reclassified or resolved classification discrepancies in 128/313 (40.9%) of these variants. Our results provide a refined framework and resource for FBN1 variant classification, and further supports the more global implications of combining gene-based knowledge with ACMG/AMP criteria and appropriate MAF cutoffs for variant classification that extend beyond FBN1.
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Affiliation(s)
- Linnea M Baudhuin
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
| | - Michelle L Kluge
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Katrina E Kotzer
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Susan A Lagerstedt
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
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21
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Ergoren MC, Turkgenc B, Teralı K, Rodoplu O, Verstraeten A, Van Laer L, Mocan G, Loeys B, Tetik O, Temel SG. Identification and characterization of a novel FBN1 gene variant in an extended family with variable clinical phenotype of Marfan syndrome. Connect Tissue Res 2019; 60:146-154. [PMID: 29732924 DOI: 10.1080/03008207.2018.1472589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Marfan syndrome (MFS) is a multi-systemic autosomal dominant condition caused by mutations in the gene (FBN1) coding for fibrillin-1. Mutations have been associated with a wide range of overlapping phenotypes. Here, we report on an extended family presenting with skeletal, ocular and cardiovascular clinical features. The 37-year-old male propositus, who had chest pain, dyspnea and shortness of breath, was first diagnosed based on the revised Ghent criteria and then subjected to molecular genetic analyses. FBN1 sequencing of the proband as well as available affected family members revealed the presence of a novel variant, c.7828G>C (p.Glu2610Gln), which was not present in any of the unaffected family members. In silico analyses demonstrated that the Glu2610 residue is part of the conserved DINE motif found at the beginning of each cbEGF domain of FBN1. The substitution of Glu2610 with Gln decreased fibrillin-1 production accordingly. Despite the fact that this variation appears to be primarily responsible for the etiology of MFS in the present family, our findings suggest that variable clinical expressions of the disease phenotype should be considered critically by the physicians.
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Affiliation(s)
- Mahmut Cerkez Ergoren
- a Department of Medical Biology, Faculty of Medicine , Near East University , Nicosia , Cyprus
| | - Burcu Turkgenc
- b Acibadem Genetic Diagnostic Center , Istanbul , Turkey
| | - Kerem Teralı
- c Department of Medical Biochemistry, Faculty of Medicine , Near East University , Nicosia , Cyprus
| | - Orhan Rodoplu
- d Department of Cardiovascular Surgery , Private Yalova Hospital , Yalova , Turkey
| | - Aline Verstraeten
- e Center for Medical Genetics , Antwerp University Hospital/University of Antwerp , Antwerp , Belgium
| | - Lut Van Laer
- e Center for Medical Genetics , Antwerp University Hospital/University of Antwerp , Antwerp , Belgium
| | - Gamze Mocan
- f Department of Pathology, Faculty of Medicine , Near East University , Nicosia , Cyprus
| | - Bart Loeys
- e Center for Medical Genetics , Antwerp University Hospital/University of Antwerp , Antwerp , Belgium
| | - Omer Tetik
- g Department of Cardiovascular Surgery , Celal Bayar University , Manisa , Turkey
| | - Sehime G Temel
- h Department of Histology and Embryology , Uludağ University , Bursa , Turkey.,i Department of Medical Genetics , Uludağ University , Bursa , Turkey.,j Department of Histology & Embryology, Faculty of Medicine , Near East University , Nicosia , Cyprus
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The Fibrillin-1 RGD Integrin Binding Site Regulates Gene Expression and Cell Function through microRNAs. J Mol Biol 2019; 431:401-421. [DOI: 10.1016/j.jmb.2018.11.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/30/2018] [Accepted: 11/23/2018] [Indexed: 11/22/2022]
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Abstract
Fibrillins are one of the major components of supramolecular fibrous structures in the extracellular matrix of elastic and nonelastic tissues, termed microfibrils. Microfibrils provide tensile strength in nonelastic tissues and scaffolds for the assembly of tropoelastin in elastic tissues, and act a regulator of growth factor bioavailability and activity in connective tissues. Mutations in fibrillins lead to a variety of connective tissue disorders including Marfan syndrome, stiff skin syndrome, dominant Weill-Marchesani syndrome, and others. Therefore, fibrillins are frequently studied to understand the pathophysiology of these diseases and to identify effective treatment strategies. Extraction of endogenous microfibrils from cells and tissues can aid in obtaining structural insights of microfibrils. Recombinant production of fibrillins is an important tool which can be utilized to study the properties of normal fibrillins and the consequences of disease causing mutations. Other means of studying the role of fibrillins in the context of various physiological settings is by knocking down the mRNA expression and analyzing its downstream consequences. It is also important to study the interactome of fibrillins by protein-protein interactions, which can be derailed in pathological situations. Interacting proteins can affect the assembly of fibrillins in cells and tissues or can affect the levels of growth factors in the matrix. This chapter describes important techniques in the field that facilitate answering relevant questions of fibrillin biology and pathophysiology.
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Brauchle E, Bauer H, Fernes P, Zuk A, Schenke-Layland K, Sengle G. Raman microspectroscopy as a diagnostic tool for the non-invasive analysis of fibrillin-1 deficiency in the skin and in the in vitro skin models. Acta Biomater 2017; 52:41-48. [PMID: 27956365 DOI: 10.1016/j.actbio.2016.12.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 10/20/2022]
Abstract
Fibrillin microfibrils and elastic fibers are critical determinants of elastic tissues where they define as tissue-specific architectures vital mechanical properties such as pliability and elastic recoil. Fibrillin microfibrils also facilitate elastic fiber formation and support the association of epithelial cells with the interstitial matrix. Mutations in fibrillin-1 (FBN1) are causative for the Marfan syndrome, a congenital multisystem disorder characterized by progressive deterioration of the fibrillin microfibril/ elastic fiber architecture in the cardiovascular, musculoskeletal, ocular, and dermal system. In this study, we utilized Raman microspectroscopy in combination with principal component analysis (PCA) to analyze the molecular consequences of fibrillin-1 deficiency in skin of a mouse model (GT8) of Marfan syndrome. In addition, full-thickness skin models incorporating murine wild-type and Fbn1GT8/GT8 fibroblasts as well as human HaCaT keratinocytes were generated and analyzed. Skin models containing GT8 fibroblasts showed an altered epidermal morphology when compared to wild-type models indicating a new role for fibrillin-1 in dermal-epidermal crosstalk. Obtained Raman spectra together with PCA allowed to discriminate between healthy and deficient microfibrillar networks in murine dermis and skin models. Interestingly, results obtained from GT8 dermis and skin models showed similar alterations in molecular signatures triggered by fibrillin-1 deficiency such as amide III vibrations and decreased levels of glycan vibrations. Overall, this study indicates that Raman microspectroscopy has the potential to analyze subtle changes in fibrillin-1 microfibrils and elastic fiber networks. Therefore Raman microspectroscopy may be utilized as a non-invasive and sensitive diagnostic tool to identify connective tissue disorders and monitor their disease progression. STATEMENT OF SIGNIFICANCE Mutations in building blocks of the fibrillin microfibril/ elastic fiber network manifest in disease conditions such as aneurysms, emphysema or lax skin. Understanding how structural changes induced by fibrillin-1 mutation impact the architecture of fibrillin microfibrils, which then translates into an altered activation state of targeted growth factors, represents a huge challenge in elucidating the genotype-phenotype correlations in connective tissue disorders such as Marfan syndrome. This study shows that Raman microspectroscopy is able to reveal structural changes in fibrillin-1 microfibrils and elastic fiber networks and to discriminate between normal and diseased networks in vivo and in vitro. Therefore Raman microspectroscopy may be utilized as a non-invasive and sensitive diagnostic tool to identify connective tissue disorders and monitor their disease progression.
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Periodontal disease and FAM20A mutations. J Hum Genet 2017; 62:679-686. [PMID: 28298625 DOI: 10.1038/jhg.2017.26] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 01/27/2017] [Accepted: 02/03/2017] [Indexed: 12/26/2022]
Abstract
Enamel-renal-gingival syndrome (ERGS; OMIM #204690), a rare autosomal recessive disorder caused by mutations in FAM20A, is characterized by nephrocalcinosis, nephrolithiasis, amelogenesis imperfecta, hypoplastic type, gingival fibromatosis and other dental abnormalities, including hypodontia and unerupted teeth with large dental follicles. We report three patients and their families with findings suggestive of ERGS. Mutation analysis of FAM20A was performed in all patients and their family members. Patients with homozygous frameshift and compound heterozygous mutations in FAM20A had typical clinical findings along with periodontitis. The other had a novel homozygous missense mutation in exon 10, mild gingival fibromatosis and renal calcifications. The periodontitis in our patients may be a syndrome component, and similar findings in previous reports suggest more than coincidence. Fam20a is an allosteric activator that increases Fam20c kinase activity. It is hypothesized that lack of FAM20A activation of FAM20C in our patients with FAM20A mutations might have caused amelogenesis imperfecta, abnormal bone remodeling and periodontitis. Nephrocalcinosis appears not to be a consistent finding of the syndrome and the missense mutation may correlate with mild gingival fibromatosis. Here we report three patients with homozygous or compound heterozygous mutations in FAM20A and findings that extend the phenotypic spectrum of this disorder, showing that protein truncation is associated with greater clinical severity.
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Abstract
Genetic testing is aiding rapid diagnosis of Marfan syndrome as a basis for management of eye, heart and skeletal disease. The affected patient's mutation can be used as a basis for prenatal or postnatal diagnosis of offspring. Preimplantation genetic diagnosis, the technique of choice, can ensure an unaffected pregnancy.
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Affiliation(s)
- Anne H Child
- Reader in Cardiovascular Genetics in the Cardiovascular and Cell Sciences Research Institute, St George's, University of London, London SW17 0RE
| | - Jose A Aragon-Martin
- Scientific Director of the Sonalee Laboratory, Cardiovascular and Cell Sciences Research Institute, St George's, University of London, London
| | - Karen Sage
- Medical Genetic Counsellor and PGD Specialist, The Bridge Centre, London Fertility Clinic, London
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New insights into the structure, assembly and biological roles of 10–12 nm connective tissue microfibrils from fibrillin-1 studies. Biochem J 2016; 473:827-38. [DOI: 10.1042/bj20151108] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 01/26/2016] [Indexed: 12/21/2022]
Abstract
The 10–12 nm diameter microfibrils of the extracellular matrix (ECM) impart both structural and regulatory properties to load-bearing connective tissues. The main protein component is the calcium-dependent glycoprotein fibrillin, which assembles into microfibrils at the cell surface in a highly regulated process involving specific proteolysis, multimerization and glycosaminoglycan interactions. In higher metazoans, microfibrils act as a framework for elastin deposition and modification, resulting in the formation of elastic fibres, but they can also occur in elastin-free tissues where they perform structural roles. Fibrillin microfibrils are further engaged in a number of cell matrix interactions such as with integrins, bone morphogenetic proteins (BMPs) and the large latent complex of transforming growth factor-β (TGFβ). Fibrillin-1 (FBN1) mutations are associated with a range of heritable connective disorders, including Marfan syndrome (MFS) and the acromelic dysplasias, suggesting that the roles of 10–12 nm diameter microfibrils are pleiotropic. In recent years the use of molecular, cellular and whole-organism studies has revealed that the microfibril is not just a structural component of the ECM, but through its network of cell and matrix interactions it can exert profound regulatory effects on cell function. In this review we assess what is known about the molecular properties of fibrillin that enable it to assemble into the 10–12 nm diameter microfibril and perform such diverse roles.
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Tjeldhorn L, Amundsen SS, Barøy T, Rand-Hendriksen S, Geiran O, Frengen E, Paus B. Qualitative and quantitative analysis of FBN1 mRNA from 16 patients with Marfan Syndrome. BMC MEDICAL GENETICS 2015; 16:113. [PMID: 26684006 PMCID: PMC4683784 DOI: 10.1186/s12881-015-0260-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 12/10/2015] [Indexed: 11/17/2022]
Abstract
Background Pathogenic mutations in FBN1, encoding the glycoprotein, fibrillin-1, cause Marfan syndrome (MFS) and related connective tissue disorders. In the present study, qualitative and quantitative effects of 16 mutations, identified in FBN1 in MFS patients with systematically described phenotypes, were investigated in vitro. Methods Qualitative analysis was performed with reverse transcription-PCR (RT-PCR) and gel electrophoresis, and quantitative analysis to determine the FBN1 mRNA levels in fibroblasts from the 16 patients with MFS was performed with real-time PCR. Results Qualitative analysis documented that the mutations c.4817-2delA and c.A4925G led to aberrant FBN1 mRNA splicing leading to in frame deletion of exon 39 and in exon 39, respectively. No difference in the mean FBN1 mRNA level was observed between the entire group of cases and controls, nor between the group of patients with missense mutations and controls. The mean expression levels associated with premature termination codon (PTC) and splice site mutations were significantly lower than the levels in patients with missense mutations. A high level of FBN1 mRNA in the patient with the missense mutation c.G2447T did not segregate with the mutation in three of his first degree relatives. No association was indicated between the FBN1 transcript level and specific phenotypic manifestations. Conclusions Abnormal FBN1 transcripts were indicated in fibroblasts from patients with the splice site mutation c.4817-2delA and the missense mutation c.A4925G. While the mean FBN1 mRNA expression level in fibroblasts from patients with splice site and PTC mutations were lower than the mean level in patients with missense mutations and controls, inter-individual variability was high. The observation that high level of FBN1 mRNA in the patient with the missense mutation c.G2447T did not segregate with the mutation in the family suggests that variable expression of the normal FBN1 allele may contribute to explain the variability in FBN1 mRNA level. Electronic supplementary material The online version of this article (doi:10.1186/s12881-015-0260-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lena Tjeldhorn
- Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424, Oslo, Norway.
| | - Silja Svanstrøm Amundsen
- Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Tuva Barøy
- Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Svend Rand-Hendriksen
- TRS National Resource Centre for Rare Disorders, Sunnaas Rehabilitation Hospital, 1450 Nesoddtangen, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Odd Geiran
- Department of Cardiothoracic Surgery, Oslo University Hospital, Box 4950, 0424 Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Eirik Frengen
- Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Benedicte Paus
- Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Andelfinger G, Loeys B, Dietz H. A Decade of Discovery in the Genetic Understanding of Thoracic Aortic Disease. Can J Cardiol 2015; 32:13-25. [PMID: 26724507 DOI: 10.1016/j.cjca.2015.10.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/14/2015] [Accepted: 10/18/2015] [Indexed: 12/23/2022] Open
Abstract
Aortic aneurysms are responsible for a significant number of all deaths in Western countries. In this review we provide a perspective on the important progress made over the past decade in the understanding of the genetics of this condition, with an emphasis on the more frequent forms of vascular smooth muscle and transforming growth factor β (TGF-β) signalling alterations. For several nonsyndromic and syndromic forms of thoracic aortic disease, a genetic basis has now been identified, with 3 main pathomechanisms that have emerged: perturbation of the TGF-β signalling pathway, disruption of the vascular smooth muscle cell (VSMC) contractile apparatus, and impairment of extracellular matrix synthesis. Because smooth muscle cells and proteins of the extracellular matrix directly regulate TGF-β signalling, this latter pathway emerges as a key component of thoracic aortic disease initiation and progression. These discoveries have revolutionized our understanding of thoracic aortic disease and provided inroads toward gene-specific stratification of treatment. Last, we outline how these genetic findings are translated into novel pharmaceutical approaches for thoracic aortic disease.
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Affiliation(s)
- Gregor Andelfinger
- Cardiovascular Genetics, Department of Pediatrics, Centre de Recherche du Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
| | - Bart Loeys
- Centre for Medical Genetics, University Hospital of Antwerp/University of Antwerp, Antwerp, Belgium; Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hal Dietz
- Howard Hughes Medical Institute and Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Division of Pediatric Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Fibrillin-containing microfibrils are key signal relay stations for cell function. J Cell Commun Signal 2015; 9:309-25. [PMID: 26449569 DOI: 10.1007/s12079-015-0307-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 09/29/2015] [Indexed: 12/26/2022] Open
Abstract
Fibrillins constitute the backbone of microfibrils in the extracellular matrix of elastic and non-elastic tissues. Mutations in fibrillins are associated with a wide range of connective tissue disorders, the most common is Marfan syndrome. Microfibrils are on one hand important for structural stability in some tissues. On the other hand, microfibrils are increasingly recognized as critical mediators and drivers of cellular signaling. This review focuses on the signaling mechanisms initiated by fibrillins and microfibrils, which are often dysregulated in fibrillin-associated disorders. Fibrillins regulate the storage and bioavailability of growth factors of the TGF-β superfamily. Cells sense microfibrils through integrins and other receptors. Fibrillins potently regulate pathways of the immune response, inflammation and tissue homeostasis. Emerging evidence show the involvement of microRNAs in disorders caused by fibrillin deficiency. A thorough understanding of fibrillin-mediated cell signaling pathways will provide important new leads for therapeutic approaches of the underlying disorders.
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The Use of Patient-Specific Induced Pluripotent Stem Cells (iPSCs) to Identify Osteoclast Defects in Rare Genetic Bone Disorders. J Clin Med 2015; 3:1490-510. [PMID: 25621177 PMCID: PMC4300535 DOI: 10.3390/jcm3041490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
More than 500 rare genetic bone disorders have been described, but for many of them only limited treatment options are available. Challenges for studying these bone diseases come from a lack of suitable animal models and unavailability of skeletal tissues for studies. Effectors for skeletal abnormalities of bone disorders may be abnormal bone formation directed by osteoblasts or anomalous bone resorption by osteoclasts, or both. Patient-specific induced pluripotent stem cells (iPSCs) can be generated from somatic cells of various tissue sources and in theory can be differentiated into any desired cell type. However, successful differentiation of hiPSCs into functional bone cells is still a challenge. Our group focuses on the use of human iPSCs (hiPSCs) to identify osteoclast defects in craniometaphyseal dysplasia. In this review, we describe the impact of stem cell technology on research for better treatment of such disorders, the generation of hiPSCs from patients with rare genetic bone disorders and current protocols for differentiating hiPSCs into osteoclasts.
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Semyachkina AN, Adyan TA, Kharabadze MN, Novikov PV, Polyakov AV. Clinical and genetic characteristics of Russian Marfan patients. RUSS J GENET+ 2015. [DOI: 10.1134/s102279541507011x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Engineered mutations in fibrillin-1 leading to Marfan syndrome act at the protein, cellular and organismal levels. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 765:7-18. [DOI: 10.1016/j.mrrev.2015.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/22/2015] [Accepted: 04/27/2015] [Indexed: 11/19/2022]
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Hanlon SD, Behzad AR, Sakai LY, Burns AR. Corneal stroma microfibrils. Exp Eye Res 2015; 132:198-207. [PMID: 25613072 DOI: 10.1016/j.exer.2015.01.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/15/2015] [Accepted: 01/17/2015] [Indexed: 12/12/2022]
Abstract
Elastic tissue was first described well over a hundred years ago and has since been identified in nearly every part of the body. In this review, we examine elastic tissue in the corneal stroma with some mention of other ocular structures which have been more thoroughly described in the past. True elastic fibers consist of an elastin core surrounded by fibrillin microfibrils. However, the presence of elastin fibers is not a requirement and some elastic tissue is comprised of non-elastin-containing bundles of microfibrils. Fibers containing a higher relative amount of elastin are associated with greater elasticity and those without elastin, with structural support. Recently it has been shown that the microfibrils, not only serve mechanical roles, but are also involved in cell signaling through force transduction and the release of TGF-β. A well characterized example of elastin-free microfibril bundles (EFMBs) is found in the ciliary zonules which suspend the crystalline lens in the eye. Through contraction of the ciliary muscle they exert enough force to reshape the lens and thereby change its focal point. It is believed that the molecules comprising these fibers do not turn-over and yet retain their tensile strength for the life of the animal. The mechanical properties of the cornea (strength, elasticity, resiliency) would suggest that EFMBs are present there as well. However, many authors have reported that, although present during embryonic and early postnatal development, EFMBs are generally not present in adults. Serial-block-face imaging with a scanning electron microscope enabled 3D reconstruction of elements in murine corneas. Among these elements were found fibers that formed an extensive network throughout the cornea. In single sections these fibers appeared as electron dense patches. Transmission electron microscopy provided additional detail of these patches and showed them to be composed of fibrils (∼10 nm diameter). Immunogold evidence clearly identified these fibrils as fibrillin EFMBs and EFMBs were also observed with TEM (without immunogold) in adult mammals of several species. Evidence of the presence of EFMBs in adult corneas will hopefully pique an interest in further studies that will ultimately improve our understanding of the cornea's biomechanical properties and its capacity to repair.
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Affiliation(s)
- Samuel D Hanlon
- College of Optometry, University of Houston, Houston, TX, 97204, USA.
| | - Ali R Behzad
- Imaging and Characterization Core Lab, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Lynn Y Sakai
- Shiners Hospital for Children and Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Alan R Burns
- College of Optometry, University of Houston, Houston, TX, 97204, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
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Liu P, Zhang H, Liu C, Wang X, Chen L, Qin C. Inactivation of Fam20C in cells expressing type I collagen causes periodontal disease in mice. PLoS One 2014; 9:e114396. [PMID: 25479552 PMCID: PMC4257665 DOI: 10.1371/journal.pone.0114396] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 11/06/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND FAM20C is a kinase that phosphorylates secretory proteins. Previous studies have shown that FAM20C plays an essential role in the formation and mineralization of bone, dentin and enamel. The present study analyzed the loss-of-function effects of FAM20C on the health of mouse periodontal tissues. METHODS By crossbreeding 2.3 kb Col 1a1-Cre mice with Fam20Cfl/fl mice, we created 2.3 kb Col 1a1-Cre;Fam20Cfl/fl (cKO) mice, in which Fam20C was inactivated in the cells that express Type I collagen. We analyzed the periodontal tissues in the cKO mice using X-ray radiography, histology, scanning electron microscopy and immunohistochemistry approaches. RESULTS The cKO mice underwent a remarkable loss of alveolar bone and cementum, along with inflammation of the periodontal ligament and formation of periodontal pockets. The osteocytes and lacuno-canalicular networks in the alveolar bone of the cKO mice showed dramatic abnormalities. The levels of bone sialoprotein, osteopontin, dentin matrix protein 1 and dentin sialoprotein were reduced in the Fam20C-deficient alveolar bone and/or cementum, while periostin and fibrillin-1 were decreased in the periodontal ligament of the cKO mice. CONCLUSION Loss of Fam20C function leads to periodontal disease in mice. The reduced levels of bone sialoprotein, osteopontin, dentin matrix protein 1, dentin sialoprotein, periostin and fibrillin-1 may contribute to the periodontal defects in the Fam20C-deficient mice.
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Affiliation(s)
- Peihong Liu
- Department of Periodontics, Harbin Medical University School of Stomatology, Harbin, Heilongjiang, 150001, China
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas, 75246, United States of America
| | - Hua Zhang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas, 75246, United States of America
| | - Chao Liu
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas, 75246, United States of America
| | - Xiaofang Wang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas, 75246, United States of America
| | - Li Chen
- Longjiang Scholar Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, China
- * E-mail: (LC); (CQ)
| | - Chunlin Qin
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas, 75246, United States of America
- * E-mail: (LC); (CQ)
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Romaniello F, Mazzaglia D, Pellegrino A, Grego S, Fiorito R, Ferlosio A, Chiariello L, Orlandi A. Aortopathy in Marfan syndrome: an update. Cardiovasc Pathol 2014; 23:261-6. [PMID: 24925629 DOI: 10.1016/j.carpath.2014.04.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/29/2014] [Accepted: 04/30/2014] [Indexed: 12/11/2022] Open
Abstract
Marfan syndrome (MFS) is an inherited autosomal dominant multisystem disease caused by mutations in the FBN1 gene encoding fibrillin-1, an extracellular matrix glycoprotein widely distributed in mesenchymal-derived tissues that provide a scaffold for elastin deposition. MFS is characterized by variable clinical manifestations, including skeletal, ocular, and cardiovascular abnormalities; ascending aortic aneurysm with ensuing dissection and rupture is the main life-threatening cardiovascular manifestation of MFS. Histological aspects of MFS aortopathy include a medial degeneration from disarray and fragmentation of elastic fibers and accumulation of basophilic ground substance areas depleted of smooth muscle cells (SMCs). Transmission electron microscopy well evidences the high number of interruptions and the thick appearance of the elastic lamellae and the accumulation of abundant extracellular glycosaminoglycan-rich material, sometimes SMCs showing a prevalent synthetic phenotype. The aberrant signaling of transforming growth factor-β (TGF-β) as the consequence of the altered structure of fibrillin-1 induces activation and the overexpression of Smad-dependent profibrotic signaling pathway and ERK1/2-mediated increased synthesis of matrix metalloproteinases. In addition, MFS is accompanied by an impaired aortic contractile function and aortic endothelial-dependent relaxation, which is caused by an enhancement of the oxidative stress and increased reactive oxygen species during the progression of the disease. Many studies are currently evaluating the contribution of TGF-β-mediated biomolecular pathways to the progression of MFS aortopathy and aneurysm development, in order to discover new targets for pharmacological strategies aimed to counteract aortic dilation.
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Affiliation(s)
- Federico Romaniello
- Institute of Anatomic Pathology, Dept. of Biomedicine and Prevention, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Donatella Mazzaglia
- Institute of Anatomic Pathology, Dept. of Biomedicine and Prevention, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Antonio Pellegrino
- Cardiac Surgery, Dept. of Experimental Medicine and Surgery, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Susanna Grego
- Cardiac Surgery, Dept. of Experimental Medicine and Surgery, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Roberto Fiorito
- General Surgery, Dept. of Biomedicine and Prevention, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Amedeo Ferlosio
- Institute of Anatomic Pathology, Dept. of Biomedicine and Prevention, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Luigi Chiariello
- Cardiac Surgery, Dept. of Experimental Medicine and Surgery, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy
| | - Augusto Orlandi
- Institute of Anatomic Pathology, Dept. of Biomedicine and Prevention, Tor Vergata University of Rome, Via Montpellier, 00133 Rome, Italy.
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Hubmacher D, Bergeron E, Fagotto-Kaufmann C, Sakai LY, Reinhardt DP. Early fibrillin-1 assembly monitored through a modifiable recombinant cell approach. Biomacromolecules 2014; 15:1456-68. [PMID: 24559401 PMCID: PMC4961472 DOI: 10.1021/bm5000696] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fibrillin proteins constitute the backbone of extra-cellular macromolecular microfibrils. Mutations in fibrillins cause heritable connective tissue disorders, including Marfan syndrome, dominant Weill-Marchesani syndrome, and stiff skin syndrome. Fibronectin provides a critical scaffold for microfibril assembly in cell culture models. Full length recombinant fibrillin-1 was expressed by HEK 293 cells, which deposited the secreted protein in a punctate pattern on the cell surface. Cocultured fibroblasts consistently triggered assembly of recombinant fibrillin-1, which was dependent on a fibronectin network formed by the fibroblasts. Deposition of recombinant fibrillin-1 on fibronectin fibers occurred first in discrete packages that subsequently extended along fibronectin fibers. Mutant fibrillin-1 harboring either a cysteine 204 to serine mutation or a RGD to RGA mutation which prevents integrin binding, did not affect fibrillin-1 assembly. In conclusion, we developed a modifiable recombinant full-length fibrillin-1 assembly system that allows for rapid analysis of critical roles in fibrillin assembly and functionality. This system can be used to study the contributions of specific residues, domains, or regions of fibrillin-1 to the biogenesis and functionality of microfibrils. It provides also a method to evaluate disease-causing mutations, and to produce microfibril-containing matrices for tissue engineering applications, for example, in designing novel vascular grafts or stents.
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Affiliation(s)
- Dirk Hubmacher
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC H3A 0C7, Canada
| | - Eric Bergeron
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC H3A 0C7, Canada
| | - Christine Fagotto-Kaufmann
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC H3A 0C7, Canada
| | - Lynn Y. Sakai
- Research Unit, Shriners Hospital for Children, Portland, OR 97239, USA
| | - Dieter P. Reinhardt
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC H3A 0C7, Canada
- Faculty of Dentistry, Division of Biomedical Sciences, McGill University, Montreal, QC H3A 0C7, Canada
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Yadin DA, Robertson IB, Jensen SA, Handford PA, Redfield C. ¹H, ¹³C and ¹⁵N assignments of the four N-terminal domains of human fibrillin-1. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:75-80. [PMID: 23264024 PMCID: PMC3955489 DOI: 10.1007/s12104-012-9456-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
Fibrillins are extracellular, disulphide-rich glycoproteins that form 10-12 nm diameter microfibrils in connective tissues. They are found in the majority of higher animals, from jellyfish to humans. Fibrillin microfibrils confer properties of elasticity and strength on connective tissue and regulate growth factor availability in the extracellular matrix (ECM). Mutations in FBN1, the human gene encoding the fibrillin-1 isoform, are linked to several inherited connective tissue disorders. The fibrillin-1 N-terminus forms many functionally-important interactions, both with other fibrillin molecules and various ECM components. In particular, the first four domains, the fibrillin unique N-terminal (FUN) and three epidermal growth factor (EGF)-like domains (FUN-EGF3), are implicated in microfibril assembly and growth factor sequestration. The structure of these domains, which comprise 134 residues, is unknown. We have produced a recombinant fragment corresponding to this region of human fibrillin-1. Here, we report (1)H, (13)C and (15)N resonance assignments of the FUN-EGF3 fragment. Assignments will facilitate structure determination, analysis of interdomain dynamics and the mapping of interaction surfaces.
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Affiliation(s)
- David A. Yadin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Ian B. Robertson
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Sacha A. Jensen
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Penny A. Handford
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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Yadin D, Robertson I, McNaught-Davis J, Evans P, Stoddart D, Handford P, Jensen S, Redfield C. Structure of the fibrillin-1 N-terminal domains suggests that heparan sulfate regulates the early stages of microfibril assembly. Structure 2013; 21:1743-56. [PMID: 24035709 PMCID: PMC3794157 DOI: 10.1016/j.str.2013.08.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 07/23/2013] [Accepted: 08/05/2013] [Indexed: 11/29/2022]
Abstract
The human extracellular matrix glycoprotein fibrillin-1 is the primary component of the 10- to 12-nm-diameter microfibrils, which perform key structural and regulatory roles in connective tissues. Relatively little is known about the molecular mechanisms of fibrillin assembly into microfibrils. Studies using recombinant fibrillin fragments indicate that an interaction between the N- and C-terminal regions drives head-to-tail assembly. Here, we present the structure of a fibrillin N-terminal fragment comprising the fibrillin unique N-terminal (FUN) and the first three epidermal growth factor (EGF)-like domains (FUN-EGF3). Two rod-like domain pairs are separated by a short, flexible linker between the EGF1 and EGF2 domains. We also show that the binding site for the C-terminal region spans multiple domains and overlaps with a heparin interaction site. These data suggest that heparan sulfate may sequester fibrillin at the cell surface via FUN-EGF3 prior to aggregation of the C terminus, thereby regulating microfibril assembly.
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Affiliation(s)
- David A. Yadin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Ian B. Robertson
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Joanne McNaught-Davis
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Paul Evans
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - David Stoddart
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Penny A. Handford
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Sacha A. Jensen
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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Nishikawa T, Yamamoto T, Honjo KI, Ichioka H, Yamamoto K, Kanamura N, Kato H, Wato M, Kubo T, Mori M, Tanaka A. Marfan's syndrome: Clinical manifestations in the oral-craniofacial area, biophysiological roles of fibrillins and elastic extracellular microfibers, and disease control of the fibrillin gene. JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY MEDICINE AND PATHOLOGY 2013. [DOI: 10.1016/j.ajoms.2013.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Quarto N, Li S, Renda A, Longaker MT. Exogenous activation of BMP-2 signaling overcomes TGFβ-mediated inhibition of osteogenesis in Marfan embryonic stem cells and Marfan patient-specific induced pluripotent stem cells. Stem Cells 2013; 30:2709-19. [PMID: 23037987 DOI: 10.1002/stem.1250] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/23/2012] [Indexed: 01/10/2023]
Abstract
Marfan syndrome (MFS) is a hereditary disease caused by mutations in the gene encoding Fibrillin-1 (FBN1) and characterized by a number of skeletal abnormalities, aortic root dilatation, and sometimes ectopia lentis. Although the molecular pathogenesis of MFS was attributed initially to a structural weakness of the fibrillin-rich microfibrils within the extracellular matrix, more recent results have documented that many of the pathogenic abnormalities in MFS are the result of alterations in TGFβ signaling. Mutations in FBN1 are therefore associated with increased activity and bioavailability of TGF-β1, which is suspected to be the basis for phenotypical similarities of FBN1 mutations in MFS and mutations in the receptors for TGFβ in Marfan syndrome-related diseases. We have previously demonstrated that unique skeletal phenotypes observed in human embryonic stem cells carrying the monogenic FBN1 mutation (MFS cells) are faithfully phenocopied by cells differentiated from induced pluripotent-stem cells (MFSiPS) derived independently from MFS patient fibroblasts. In this study, we aimed to determine further the biochemical features of transducing signaling(s) in MFS stem cells and MFSiPS cells highlighting a crosstalk between TGFβ and BMP signaling. Our results revealed that enhanced activation of TGFβ signaling observed in MFS cells decreased their endogenous BMP signaling. Moreover, exogenous BMP antagonized the enhanced TGFβ signaling in both MFS stem cells and MFSiPS cells therefore, rescuing their ability to undergo osteogenic differentiation. This study advances our understanding of molecular mechanisms underlying the pathogenesis of bone loss/abnormal skeletogenesis in human diseases caused by mutations in FBN1.
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Affiliation(s)
- Natalina Quarto
- Hagey Laboratory for Pediatric Regenerative Medicine, Department of Surgery, Stanford University, School of Medicine, Stanford, California 94305, USA.
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Potter KJ, Creighton S, Armstrong L, Eydoux P, Duncan W, Penny DJ, Fan Y, Gibson WT. The c.7409G>A (p.Cys2470Tyr) Variant of FBN1: Phenotypic Variability across Three Generations. Mol Syndromol 2013; 4:125-35. [PMID: 23653584 DOI: 10.1159/000347163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2012] [Indexed: 11/19/2022] Open
Abstract
Marfan syndrome is an autosomal dominant connective tissue disorder caused by mutations in the fibrillin gene FBN1, which encodes an extracellular matrix glycoprotein. Major features of Marfan syndrome occur in the ocular, cardiovascular, and skeletal systems as well as in the dura mater. Approximately 60% of known disease-causing mutations are missense mutations of single amino acid residues. Effects on the cardiovascular system are classically associated with mutations in exons 24-32 of the 65 FBN1 exons and many, though not all, reports associate missense mutations in exons 59-65 with a mild cardiovascular phenotype. Here we present 5 related individuals among whom a c.7409G>A (p.Cys2470Tyr) missense variant in exon 59 of FBN1 is associated with significant cardiovascular features. The index case also had an apparently de novo 46,XX,del(5)(q33.1q33.3) deletion on chromosome 5. This family demonstrates skeletal, dermatological and neurological features consistent with Marfan syndrome but lacks significant ophthalmological findings to date. These findings suggest that FBN1 C-terminal missense mutations may not confer the ophthalmological features of Marfan syndrome, but they also confer a more significant risk for cardiovascular pathology than that suggested by previous studies. Furthermore, clinical data from this family supports the previously reported association of dural ectasia with C-terminal mutations.
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Affiliation(s)
- K J Potter
- Department of Pathology and Laboratory Medicine, University of British Columbia, B.C., Canada ; Department of Child and Family Research Institute, University of British Columbia, B.C., Canada
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Davis MR, Summers KM. Structure and function of the mammalian fibrillin gene family: implications for human connective tissue diseases. Mol Genet Metab 2012; 107:635-47. [PMID: 22921888 DOI: 10.1016/j.ymgme.2012.07.023] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 07/30/2012] [Accepted: 07/30/2012] [Indexed: 12/31/2022]
Abstract
Fibrillins and latent transforming growth factor β binding proteins (LTBPs) are components of the extracellular matrix of connective tissue. While fibrillins are integral to the 10nm microfibrils, and often associated with elastin, all family members are likely to have an additional role in regulating the bioavailability of transforming growth factor β (TGBβ). Both fibrillins and LTBPs are large glycoproteins, containing a series of calcium binding epidermal growth factor domains as well as a number of copies of a unique 8 cysteine domain found only in this protein superfamily. There are three mammalian fibrillins and four LTBPs. Fibrillin monomers link head to tail in microfibrils which can then form two and three dimensional structures. In some tissues elastin is recruited to the fibrillin microfibrils to provide elasticity to the tissue. LTBPs are part of the TGBβ large latent complex which sequesters TGBβ in the extracellular matrix. Fibrillin-1 appears to bind to LTBPs to assist in this process and is thus involved in regulating the bioavailability of TGBβ. Mutation of fibrillin genes results in connective tissue phenotypes which reflect both the increased level of active TGBβ and the structural failure of the extracellular matrix due to the absence or abnormality of fibrillin protein. Fibrillinopathies include Marfan syndrome, familial ectopia lentis, familial thoracic aneurysm (mutations of FBN1) and congenital contractural arachnodactyly (mutation of FBN2). There are no diseases currently associated with mutation of FBN3 in humans, and this gene is no longer active in rodents. Expression patterns of fibrillin genes are consistent with their role in extracellular matrix structure of connective tissue. FBN1 expression is high in most cell types of mesenchymal origin, particularly bone. Human and mouse FBN2 expression is high in fetal cells and has more restricted expression in mesenchymal cell types postnatally. FBN3 is expressed early in development (embryonic and fetal tissues) in humans. The fibrillins are thus important in maintaining the structure and integrity of the extracellular matrix and, in combination with their sequence family members the LTBPs, also contribute to the regulation of the TGFβ family of major growth factors.
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Affiliation(s)
- Margaret R Davis
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
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Cain SA, McGovern A, Baldwin AK, Baldock C, Kielty CM. Fibrillin-1 mutations causing Weill-Marchesani syndrome and acromicric and geleophysic dysplasias disrupt heparan sulfate interactions. PLoS One 2012; 7:e48634. [PMID: 23133647 PMCID: PMC3487758 DOI: 10.1371/journal.pone.0048634] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/28/2012] [Indexed: 11/19/2022] Open
Abstract
The extracellular glycoprotein fibrillin-1 forms microfibrils that act as the template for elastic fibers. Most mutations in fibrillin-1 cause Marfan syndrome with severe cardiovascular and ocular symptoms, and tall stature. This is in contrast to mutations within a heparin-binding TB domain (TB5), which is downstream of the arg-gly-asp cell adhesion domain, which can cause Weill-Marchesani syndrome (WMS) or Acromicric (AD) and Geleophysic Dysplasias (GD). WMS is characterized by short limbs, joint stiffness and ocular defects, whilst fibrillin-1 AD and GD have severe short stature, joint defects and thickened skin. We previously showed that TB5 binds heparin. Here, we show that the corresponding region of fibrillin-2 binds heparin very poorly, highlighting a novel functional difference between the two isoforms. This finding enabled us to map heparin/heparan sulfate binding to two sites on fibrillin-1 TB5 using a mutagenesis approach. Once these sites were mapped, we were able to investigate whether disease-causing mutations in this domain disrupt binding to HS. We show that a WMS deletion mutant, and five AD and GD point mutants all have disrupted heparin binding to TB5. These data provide insights into the biology of fibrillins and the pathologies of WMS, AD and GD.
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Affiliation(s)
- Stuart A Cain
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
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45
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Strydom H, Maltha JC, Kuijpers-Jagtman AM, Von den Hoff JW. The oxytalan fibre network in the periodontium and its possible mechanical function. Arch Oral Biol 2012; 57:1003-11. [PMID: 22784380 DOI: 10.1016/j.archoralbio.2012.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 05/29/2012] [Accepted: 06/13/2012] [Indexed: 01/20/2023]
Abstract
The biomechanical character of the periodontal ligament (PDL) is crucial in its response to functional and orthodontic forces. Collagen has been the primary subject of investigations in this field. Several studies, however, indicate that oxytalan fibres, which belong to the elastic fibre family, also contribute to the biomechanical character and behaviour of the PDL. In order to elucidate this, we have evaluated the available literature on the oxytalan fibre network within the PDL and supra-alveolar tissues with respect to development, morphology and distribution, and response to mechanical stimulation. To this end, we have combined the classical histological studies with more recent in vitro studies. Oxytalan fibres develop simultaneously with the root and the vascular system within the PDL. A close association between oxytalan fibres and the vascular system also remains later in life, suggesting a role in vascular support. Mechanical loading of the PDL, through orthodontic force application, appears to induce an increase in the number, size, and length of oxytalan fibres. In line with this, in vitro stretching of PDL fibroblasts (PDLFs) results in an increased production of fibrillin, a major structural component of the microfibrils that make up oxytalan fibres. The available data suggest a mechanical function for oxytalan, but to date experimental data are limited. Further research is required to clarify their exact mechanical function and possible role in orthodontic tooth movement.
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Affiliation(s)
- Hardus Strydom
- Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, The Netherlands
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Wang WJ, Han P, Zheng J, Hu FY, Zhu Y, Xie JS, Guo J, Zhang Z, Dong J, Zheng GY, Cao H, Liu TS, Fu Q, Sun L, Yang BB, Tian XL. Exon 47 skipping of fibrillin-1 leads preferentially to cardiovascular defects in patients with thoracic aortic aneurysms and dissections. J Mol Med (Berl) 2012; 91:37-47. [PMID: 22772377 DOI: 10.1007/s00109-012-0931-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 05/06/2012] [Accepted: 06/15/2012] [Indexed: 02/02/2023]
Abstract
Excessive activation of the transforming growth factor beta signaling pathway and disorganized cellular skeleton caused by genetic mutations are known to be responsible for the inherited thoracic aortic aneurysms and dissections (TAAD), a life-threatening vascular disease. To investigate the genotype-phenotype correlation, we screened genetic mutations of fibrillin-1 (FBN1), transforming growth factor-β receptor-1 (TGFBR1) and transforming growth factor-β receptor-2 (TGFBR2) for TAAD in 7 affected families and 22 sporadic patients. Of 19 potential mutations identified in FBN1, 11 appeared novel while the others were recurrent. Two mutations were detected in TGFBR2. Eight patients carried no mutation in either of these genes. Characterization of FBN1 c.5917+6T>C in transfected HEK293 cells demonstrated that it caused skipping of exon 47, leading to the loss of the 33th calcium binding epidermal growth factor-like domain associated with Marfan syndrome. Compared with exon 46, skipping of 47 did not cause patients ectopia lentis in all carriers. To correlate genotypes with phenotypes in different human ancestries, we reviewed the published mutational studies on FBN1 and found that the probability of cardiovascular defects were significantly increased in Chinese patients with premature termination codon or splicing mutations than those with missense mutations (91.7 % vs 54.2 %, P = 0.0307) or with noncysteine-involved point mutations than those with cysteine-involved mutations (88.9 % vs 33.3 %, P = 0.0131). Thus, we conclude that exon 47 skipping of FBN1 leads preferentially to cardiovascular defects and human ancestries influence genotype-phenotype correlation in TAAD.
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Affiliation(s)
- Wen-Jing Wang
- Department of Human Population Genetics, Institute of Molecular Medicine, Peking University, 5 Yiheyuan Rd, Beijing 100871, China
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47
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Jensen SA, Robertson IB, Handford PA. Dissecting the fibrillin microfibril: structural insights into organization and function. Structure 2012; 20:215-25. [PMID: 22325771 DOI: 10.1016/j.str.2011.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 12/07/2011] [Accepted: 12/09/2011] [Indexed: 01/09/2023]
Abstract
Force-bearing tissues such as blood vessels, lungs, and ligaments depend on the properties of elasticity and flexibility. The 10 to 12 nm diameter fibrillin microfibrils play vital roles in maintaining the structural integrity of these highly dynamic tissues and in regulating extracellular growth factors. In humans, defective microfibril function results in several diseases affecting the skin, cardiovascular, skeletal, and ocular systems. Despite the discovery of fibrillin-1 having occurred more than two decades ago, the structure and organization of fibrillin monomers within the microfibrils are still controversial. Recent structural data have revealed strategies by which fibrillin is able to maintain its architecture in dynamic tissues without compromising its ability to interact with itself and other cell matrix components. This review summarizes our current knowledge of microfibril structure, from individual fibrillin domains and the calcium-dependent tuning of pairwise interdomain interactions to microfibril dynamics, and how this relates to microfibril function in health and disease.
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Affiliation(s)
- Sacha A Jensen
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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48
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Piha-Gossack A, Sossin W, Reinhardt DP. The evolution of extracellular fibrillins and their functional domains. PLoS One 2012; 7:e33560. [PMID: 22438950 PMCID: PMC3306419 DOI: 10.1371/journal.pone.0033560] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 02/14/2012] [Indexed: 11/19/2022] Open
Abstract
Fibrillins constitute the major backbone of multifunctional microfibrils in elastic and non-elastic extracellular matrices, and are known to interact with several binding partners including tropoelastin and integrins. Here, we study the evolution of fibrillin proteins. Following sequence collection from 39 organisms representative of the major evolutionary groups, molecular evolutionary genetics and phylogeny inference software were used to generate a series of evolutionary trees using distance-based and maximum likelihood methods. The resulting trees support the concept of gene duplication as a means of generating the three vertebrate fibrillins. Beginning with a single fibrillin sequence found in invertebrates and jawless fish, a gene duplication event, which coincides with the appearance of elastin, led to the creation of two genes. One of the genes significantly evolved to become the gene for present-day fibrillin-1, while the other underwent evolutionary changes, including a second duplication, to produce present-day fibrillin-2 and fibrillin-3. Detailed analysis of several sequences and domains within the fibrillins reveals distinct similarities and differences across various species. The RGD integrin-binding site in TB4 of all fibrillins is conserved in cephalochordates and vertebrates, while the integrin-binding site within cbEGF18 of fibrillin-3 is a recent evolutionary change. The proline-rich domain in fibrillin-1, glycine-rich domain in fibrillin-2 and proline-/glycine-rich domain in fibrillin-3 are found in all analyzed tetrapod species, whereas it is completely replaced with an EGF-like domain in cnidarians, arthropods, molluscs and urochordates. All collected sequences contain the first 9-cysteine hybrid domain, and the second 8-cysteine hybrid domain with exception of arthropods containing an atypical 10-cysteine hybrid domain 2. Furin cleavage sites within the N- and C-terminal unique domains were found for all analyzed fibrillin sequences, indicating an essential role for processing of the fibrillin pro-proteins. The four cysteines in the unique N-terminus and the two cysteines in the unique C-terminus are also highly conserved.
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Affiliation(s)
- Adam Piha-Gossack
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Wayne Sossin
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Dieter P. Reinhardt
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
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Colombatti A, Spessotto P, Doliana R, Mongiat M, Bressan GM, Esposito G. The EMILIN/Multimerin family. Front Immunol 2012; 2:93. [PMID: 22566882 PMCID: PMC3342094 DOI: 10.3389/fimmu.2011.00093] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 12/21/2011] [Indexed: 01/12/2023] Open
Abstract
Elastin microfibrillar interface proteins (EMILINs) and Multimerins (EMILIN1, EMILIN2, Multimerin1, and Multimerin2) constitute a four member family that in addition to the shared C-terminus gC1q domain typical of the gC1q/TNF superfamily members contain a N-terminus unique cysteine-rich EMI domain. These glycoproteins are homotrimeric and assemble into high molecular weight multimers. They are predominantly expressed in the extracellular matrix and contribute to several cellular functions in part associated with the gC1q domain and in part not yet assigned nor linked to other specific regions of the sequence. Among the latter is the control of arterial blood pressure, the inhibition of Bacillus anthracis cell cytotoxicity, the promotion of cell death, the proangiogenic function, and a role in platelet hemostasis. The focus of this review is to highlight the multiplicity of functions and domains of the EMILIN/Multimerin family with a particular emphasis on the regulatory role played by the ligand-receptor interactions of the gC1q domain. EMILIN1 is the most extensively studied member both from the structural and functional point of view. The structure of the gC1q of EMILIN1 solved by NMR highlights unique characteristics compared to other gC1q domains: it shows a marked decrease of the contact surface of the trimeric assembly and while conserving the jelly-roll topology with two β-sheets of antiparallel strands it presents a nine-stranded β-sandwich fold instead of the usual 10-stranded fold. This is likely due to the insertion of nine residues that disrupt the ordered strand organization and forma a highly dynamic protruding loop. In this loop the residue E933 is the site of interaction between gC1q and the α4β1 and α9β1 integrins, and contrary to integrin occupancy that usually upregulates cell growth, when gC1q is ligated by the integrin the cells reduce their proliferative activity.
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Affiliation(s)
- Alfonso Colombatti
- Experimental Oncology 2, Centro di Riferimento Oncologico, Istituto di Ricerca e Cura a Carattere Scientifico Aviano, Italy.
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50
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Zadeh N, Bernstein JA, Niemi AK, Dugan S, Kwan A, Liang D, Hyland JC, Hoyme HE, Hudgins L, Manning MA. Ectopia lentis as the presenting and primary feature in Marfan syndrome. Am J Med Genet A 2011; 155A:2661-8. [PMID: 21932315 DOI: 10.1002/ajmg.a.34245] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 07/14/2011] [Indexed: 11/08/2022]
Abstract
Marfan syndrome (MFS) is a multisystem connective tissue disorder with primary involvement of the ocular, cardiovascular, and skeletal systems. We report on eight patients, all presenting initially with bilateral ectopia lentis (EL) during early childhood. These individuals did not have systemic manifestations of MFS, and did not fulfill the revised Ghent diagnostic criteria. However, all patients had demonstratable, disease-causing missense mutations in the FBN1 gene. Based on molecular results, cardiovascular imaging was recommended and led to the identification of mild aortic root changes in seven of the eight patients. The remaining patient had mitral valve prolapse with a normal appearing thoracic aorta. The findings presented in this paper validate the necessity of FBN1 gene testing in all individuals presenting with isolated EL. As we observed, these individuals are at increased risk of cardiovascular complications. Furthermore, we also noted that the majority of our patient cohort's mutations occurred in the 5' portion of the FBN1 gene, and were found to affect highly conserved cysteine residues, which may indicate a possible genotype-phenotype correlation. We conclude that in patients with isolated features of EL, FBN1 mutation analysis is necessary to aid in providing prompt diagnosis, and to identify patients at risk for potentially life-threatening complications. Additionally, knowledge of the type and location of an FBN1 mutation may be useful in providing further clinical correlation regarding phenotypic progression and appropriate medical management.
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Affiliation(s)
- Neda Zadeh
- Department of Pediatrics, Division of Medical Genetics, Stanford University, Stanford, California, USA.
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