1
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Wozny MR, Nelea V, Siddiqui IFS, Wanga S, de Waard V, Strauss M, Reinhardt DP. Microfibril-associated glycoprotein 4 forms octamers that mediate interactions with elastogenic proteins and cells. Nat Commun 2024; 15:4015. [PMID: 38740766 DOI: 10.1038/s41467-024-48377-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 04/29/2024] [Indexed: 05/16/2024] Open
Abstract
Microfibril-associated glycoprotein 4 (MFAP4) is a 36-kDa extracellular matrix glycoprotein with critical roles in organ fibrosis, chronic obstructive pulmonary disease, and cardiovascular disorders, including aortic aneurysms. MFAP4 multimerises and interacts with elastogenic proteins, including fibrillin-1 and tropoelastin, and with cells via integrins. Structural details of MFAP4 and its potential interfaces for these interactions are unknown. Here, we present a cryo-electron microscopy structure of human MFAP4. In the presence of calcium, MFAP4 assembles as an octamer, where two sets of homodimers constitute the top and bottom halves of each octamer. Each homodimer is linked together by an intermolecular disulphide bond. A C34S missense mutation prevents disulphide-bond formation between monomers but does not prevent octamer assembly. The atomic model, built into the 3.55 Å cryo-EM map, suggests that salt-bridge interactions mediate homodimer assembly, while non-polar residues form the interface between octamer halves. In the absence of calcium, an MFAP4 octamer dissociates into two tetramers. Binding studies with fibrillin-1, tropoelastin, LTBP4, and small fibulins show that MFAP4 has multiple surfaces for protein-protein interactions, most of which depend upon MFAP4 octamer assembly. The C34S mutation does not affect these protein interactions or cell interactions. MFAP4 assemblies with fibrillin-1 abrogate MFAP4 interactions with cells.
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Affiliation(s)
- Michael R Wozny
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada
| | - Valentin Nelea
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| | | | - Shaynah Wanga
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Amsterdam, The Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Vivian de Waard
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Amsterdam, The Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Mike Strauss
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada.
| | - Dieter P Reinhardt
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada.
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada.
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2
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Li L, Huang J, Liu Y. The extracellular matrix glycoprotein fibrillin-1 in health and disease. Front Cell Dev Biol 2024; 11:1302285. [PMID: 38269088 PMCID: PMC10806136 DOI: 10.3389/fcell.2023.1302285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/19/2023] [Indexed: 01/26/2024] Open
Abstract
Fibrillin-1 (FBN1) is a large, cysteine-rich, calcium binding extracellular matrix glycoprotein encoded by FBN1 gene. It serves as a structural component of microfibrils and provides force-bearing mechanical support in elastic and nonelastic connective tissue. As such, mutations in the FBN1 gene can cause a wide variety of genetic diseases such as Marfan syndrome, an autosomal dominant disorder characterized by ocular, skeletal and cardiovascular abnormalities. FBN1 also interacts with numerous microfibril-associated proteins, growth factors and cell membrane receptors, thereby mediating a wide range of biological processes such as cell survival, proliferation, migration and differentiation. Dysregulation of FBN1 is involved in the pathogenesis of many human diseases, such as cancers, cardiovascular disorders and kidney diseases. Paradoxically, both depletion and overexpression of FBN1 upregulate the bioavailability and signal transduction of TGF-β via distinct mechanisms in different settings. In this review, we summarize the structure and expression of FBN1 and present our current understanding of the functional role of FBN1 in various human diseases. This knowledge will allow to develop better strategies for therapeutic intervention of FBN1 related diseases.
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Affiliation(s)
- Li Li
- State Key Laboratory of Organ Failure Research, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, Guangzhou, China
| | - Junxin Huang
- State Key Laboratory of Organ Failure Research, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, Guangzhou, China
| | - Youhua Liu
- State Key Laboratory of Organ Failure Research, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, Guangzhou, China
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3
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Alonso F, Dong Y, Li L, Jahjah T, Dupuy JW, Fremaux I, Reinhardt DP, Génot E. Fibrillin-1 regulates endothelial sprouting during angiogenesis. Proc Natl Acad Sci U S A 2023; 120:e2221742120. [PMID: 37252964 PMCID: PMC10265973 DOI: 10.1073/pnas.2221742120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 04/20/2023] [Indexed: 06/01/2023] Open
Abstract
Fibrillin-1 is an extracellular matrix protein that assembles into microfibrils which provide critical functions in large blood vessels and other tissues. Mutations in the fibrillin-1 gene are associated with cardiovascular, ocular, and skeletal abnormalities in Marfan syndrome. Here, we reveal that fibrillin-1 is critical for angiogenesis which is compromised by a typical Marfan mutation. In the mouse retina vascularization model, fibrillin-1 is present in the extracellular matrix at the angiogenic front where it colocalizes with microfibril-associated glycoprotein-1, MAGP1. In Fbn1C1041G/+ mice, a model of Marfan syndrome, MAGP1 deposition is reduced, endothelial sprouting is decreased, and tip cell identity is impaired. Cell culture experiments confirmed that fibrillin-1 deficiency alters vascular endothelial growth factor-A/Notch and Smad signaling which regulate the acquisition of endothelial tip cell/stalk cell phenotypes, and we showed that modulation of MAGP1 expression impacts these pathways. Supplying the growing vasculature of Fbn1C1041G/+ mice with a recombinant C-terminal fragment of fibrillin-1 corrects all defects. Mass spectrometry analyses showed that the fibrillin-1 fragment alters the expression of various proteins including ADAMTS1, a tip cell metalloprotease and matrix-modifying enzyme. Our data establish that fibrillin-1 is a dynamic signaling platform in the regulation of cell specification and matrix remodeling at the angiogenic front and that mutant fibrillin-1-induced defects can be rescued pharmacologically using a C-terminal fragment of the protein. These findings, identify fibrillin-1, MAGP1, and ADAMTS1 in the regulation of endothelial sprouting, and contribute to our understanding of how angiogenesis is regulated. This knowledge may have critical implications for people with Marfan syndrome.
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Affiliation(s)
- Florian Alonso
- Université de BordeauxF-33000Bordeaux, France
- INSERM U1026, BioTisF-33000Bordeaux, France
| | - Yuechao Dong
- Université de BordeauxF-33000Bordeaux, France
- INSERM U1026, BioTisF-33000Bordeaux, France
| | - Ling Li
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QCH3A 0C7, Canada
| | - Tiya Jahjah
- Université de BordeauxF-33000Bordeaux, France
- INSERM U1026, BioTisF-33000Bordeaux, France
| | | | - Isabelle Fremaux
- Université de BordeauxF-33000Bordeaux, France
- INSERM U1026, BioTisF-33000Bordeaux, France
| | - Dieter P. Reinhardt
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QCH3A 0C7, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QCH3A 0C7, Canada
| | - Elisabeth Génot
- Université de BordeauxF-33000Bordeaux, France
- INSERM U1026, BioTisF-33000Bordeaux, France
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4
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Summers KM, Bush SJ, Davis MR, Hume DA, Keshvari S, West JA. Fibrillin-1 and asprosin, novel players in metabolic syndrome. Mol Genet Metab 2023; 138:106979. [PMID: 36630758 DOI: 10.1016/j.ymgme.2022.106979] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Fibrillin-1 is a major component of the extracellular microfibrils, where it interacts with other extracellular matrix proteins to provide elasticity to connective tissues, and regulates the bioavailability of TGFβ family members. A peptide consisting of the C-terminal 140 amino acids of fibrillin-1 has recently been identified as a glucogenic hormone, secreted from adipose tissue during fasting and targeting the liver to release glucose. This fragment, called asprosin, also signals in the hypothalamus to stimulate appetite. Asprosin levels are correlated with many of the pathologies indicative of metabolic syndrome, including insulin resistance and obesity. Previous studies and reviews have addressed the therapeutic potential of asprosin as a target in obesity, diabetes and related conditions without considering mechanisms underlying the relationship between generation of asprosin and expression of the much larger fibrillin-1 protein. Profibrillin-1 undergoes obligatory cleavage at the cell surface as part of its assembly into microfibrils, producing the asprosin peptide as well as mature fibrillin-1. Patterns of FBN1 mRNA expression are inconsistent with the necessity for regulated release of asprosin. The asprosin peptide may be protected from degradation in adipose tissue. We present evidence for an alternative possibility, that asprosin mRNA is generated independently from an internal promoter within the 3' end of the FBN1 gene, which would allow for regulation independent of fibrillin-synthesis and is more economical of cellular resources. The discovery of asprosin opened exciting possibilities for treatment of metabolic syndrome related conditions, but there is much to be understood before such therapies could be introduced into the clinic.
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Affiliation(s)
- Kim M Summers
- Mater Research Institute-University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, Queensland 4102, Australia.
| | - Stephen J Bush
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford OX3 9DS, United Kingdom.
| | - Margaret R Davis
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, United Kingdom
| | - David A Hume
- Mater Research Institute-University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, Queensland 4102, Australia.
| | - Sahar Keshvari
- Mater Research Institute-University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, Queensland 4102, Australia.
| | - Jennifer A West
- Faculty of Medicine, The University of Queensland, Mayne Medical Building, 288 Herston Road, Herston, Queensland 4006, Australia.
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5
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Fibrillin-1 Regulates Arteriole Integrity in the Retina. Biomolecules 2022; 12:biom12101330. [PMID: 36291539 PMCID: PMC9599515 DOI: 10.3390/biom12101330] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 11/26/2022] Open
Abstract
Fibrillin-1 is an extracellular matrix protein that assembles into microfibrils that provide critical functions in large blood vessels and other tissues. Mutations in the fibrillin-1 gene are associated with cardiovascular, ocular, and skeletal abnormalities in Marfan syndrome. Fibrillin-1 is a component of the wall of large arteries but has been poorly described in other vessels. We examined the microvasculature in the retina using wild type mice and two models of Marfan syndrome, Fbn1C1041G/+ and Fbn1mgR/mgR. In the mouse retina, fibrillin-1 was detected around arterioles, in close contact with the basement membrane, where it colocalized with MAGP1. Both a mutation in fibrillin-1 or fibrillin-1 underexpression characteristically altered the microvasculature. In Fbn1C1041G/+ and Fbn1mgR/mgR mice, arterioles were enlarged with reduced MAGP1 deposition and focal loss of smooth muscle cell coverage. Losartan, which prevents aortic enlargement in Fbn1C1041G/+ mice, prevented smooth muscle cell loss and vessel leakiness when administrated in a preventive mode. Moreover, losartan also partially rescued the defects in a curative mode. Thus, fibrillin-1/MAGP1 performs essential functions in arteriolar integrity and mutant fibrillin-1-induced defects can be prevented or partially rescued pharmacologically. These new findings could have implications for people with Marfan syndrome.
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6
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Mead TJ, Martin DR, Wang LW, Cain SA, Gulec C, Cahill E, Mauch J, Reinhardt D, Lo C, Baldock C, Apte SS. Proteolysis of fibrillin-2 microfibrils is essential for normal skeletal development. eLife 2022; 11:71142. [PMID: 35503090 PMCID: PMC9064305 DOI: 10.7554/elife.71142] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 04/13/2022] [Indexed: 01/08/2023] Open
Abstract
The embryonic extracellular matrix (ECM) undergoes transition to mature ECM as development progresses, yet few mechanisms ensuring ECM proteostasis during this period are known. Fibrillin microfibrils are macromolecular ECM complexes serving structural and regulatory roles. In mice, Fbn1 and Fbn2, encoding the major microfibrillar components, are strongly expressed during embryogenesis, but fibrillin-1 is the major component observed in adult tissue microfibrils. Here, analysis of Adamts6 and Adamts10 mutant mouse embryos, lacking these homologous secreted metalloproteases individually and in combination, along with in vitro analysis of microfibrils, measurement of ADAMTS6-fibrillin affinities and N-terminomics discovery of ADAMTS6-cleaved sites, identifies a proteostatic mechanism contributing to postnatal fibrillin-2 reduction and fibrillin-1 dominance. The lack of ADAMTS6, alone and in combination with ADAMTS10 led to excess fibrillin-2 in perichondrium, with impaired skeletal development defined by a drastic reduction of aggrecan and cartilage link protein, impaired BMP signaling in cartilage, and increased GDF5 sequestration in fibrillin-2-rich tissue. Although ADAMTS6 cleaves fibrillin-1 and fibrillin-2 as well as fibronectin, which provides the initial scaffold for microfibril assembly, primacy of the protease-substrate relationship between ADAMTS6 and fibrillin-2 was unequivocally established by reversal of the defects in Adamts6-/- embryos by genetic reduction of Fbn2, but not Fbn1.
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Affiliation(s)
- Timothy J Mead
- Department of Biomedical Engineering and Musculoskeletal Research Center, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States
| | - Daniel R Martin
- Department of Biomedical Engineering and Musculoskeletal Research Center, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States
| | - Lauren W Wang
- Department of Biomedical Engineering and Musculoskeletal Research Center, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States
| | - Stuart A Cain
- Division of Cell-Matrix Biology and Regenerative Medicine, Wellcome Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Cagri Gulec
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Elisabeth Cahill
- Department of Biomedical Engineering and Musculoskeletal Research Center, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States
| | - Joseph Mauch
- Department of Biomedical Engineering and Musculoskeletal Research Center, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States
| | - Dieter Reinhardt
- Faculty of Medicine and Health Sciences and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Canada
| | - Cecilia Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Clair Baldock
- Division of Cell-Matrix Biology and Regenerative Medicine, Wellcome Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Suneel S Apte
- Department of Biomedical Engineering and Musculoskeletal Research Center, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States
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7
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Muthu ML, Tiedemann K, Fradette J, Komarova S, Reinhardt DP. Fibrillin-1 regulates white adipose tissue development, homeostasis, and function. Matrix Biol 2022; 110:106-128. [DOI: 10.1016/j.matbio.2022.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 04/12/2022] [Accepted: 05/04/2022] [Indexed: 12/28/2022]
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8
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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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9
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Madhangi M, Dutta D, Show S, Bhat VK, Rather MI, Tiwari A, Singh N, Duvvari MR, Murthy GJ, Kumar A, Nongthomba U. Exome sequencing and functional studies in zebrafish identify WDR8 as the causative gene for isolated Microspherophakia in Indian families. Hum Mol Genet 2021; 30:467-484. [PMID: 33693649 DOI: 10.1093/hmg/ddab061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/23/2021] [Accepted: 02/23/2021] [Indexed: 11/14/2022] Open
Abstract
Isolated Microspherophakia (MSP) is an autosomal recessive disorder characterized by a smaller than normal spherical lens. Till date, LTBP2 is the only gene shown to cause MSP. We used homozygosity mapping and whole-exome sequencing and identified a homozygous mutation, c.1148C > T (p.Pro383Leu), in the WDR8 (or WRAP73) gene in two Indian MSP families. In vitro experiments showed that the missense mutation renders the protein unstable. WDR8 is a centriolar protein that has important roles in centrosomal assembly, spindle pole formation and ciliogenesis. Co-immunoprecipitation experiments from HeLa cells indicated that the mutation interferes with the interaction of WDR8 with its binding partners. In zebrafish, both morpholino-mediated knockdown and CRISPR/Cas knockout of wdr8 resulted in decreased eye and lens size. The lack of wdr8 affected cell cycle progression in the retinal cells, causing a reduction in cell numbers in the retina and lens. The reduction in eye size and the cell cycle defects were rescued by exogenous expression of the human wild-type WDR8. However, the human mutant WDR8 (p.Pro383Leu) was unable to rescue the eye defects, indicating that the missense mutation abrogates WDR8 protein function. Thus, our zebrafish results suggested that WDR8 is the causative gene for MSP in these Indian families.
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Affiliation(s)
- M Madhangi
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Debanjan Dutta
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Sautan Show
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Vishwanath K Bhat
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Mohammad I Rather
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Ankana Tiwari
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Nivedita Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Maheswara R Duvvari
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Gowri J Murthy
- Prabha Eye Clinic and Research Centre, Bangalore 560070, India
| | - Arun Kumar
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Upendra Nongthomba
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
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10
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Lockhart-Cairns MP, Newandee H, Thomson J, Weiss AS, Baldock C, Tarakanova A. Transglutaminase-Mediated Cross-Linking of Tropoelastin to Fibrillin Stabilises the Elastin Precursor Prior to Elastic Fibre Assembly. J Mol Biol 2020; 432:5736-5751. [PMID: 32898582 PMCID: PMC7610145 DOI: 10.1016/j.jmb.2020.08.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/07/2020] [Accepted: 08/26/2020] [Indexed: 02/05/2023]
Abstract
Elastic fibres are essential components of all mammalian elastic tissues such as blood vessels, lung and skin, and are critically important for the mechanical properties they endow. The main components of elastic fibres are elastin and fibrillin, where correct formation of elastic fibres requires a fibrillin microfibril scaffold for the deposition of elastin. It has been demonstrated previously that the interaction between fibrillin and tropoelastin, the elastin precursor, increases the rate of assembly of tropoelastin. Furthermore, tropoelastin and fibrillin can be cross-linked by transglutaminase-2, but the function of cross-linking on their elastic properties is yet to be elucidated. Here we show that transglutaminase cross-linking supports formation of a 1:1 stoichiometric fibrillin-tropoelastin complex. SAXS data show that the complex retains features of the individual proteins but is elongated supporting end-to-end assembly. Elastic network models were constructed to compare the dynamics of tropoelastin and fibrillin individually as well as in the cross-linked complex. Normal mode analysis was performed to determine the structures' most energetically favourable, biologically accessible motions which show that within the complex, tropoelastin is less mobile and this molecular stabilisation extends along the length of the tropoelastin molecule to regions remote from the cross-linking site. Together, these data suggest a long-range stabilising effect of cross-linking that occurs due to the covalent linkage of fibrillin to tropoelastin. This work provides insight into the interactions of tropoelastin and fibrillin and how cross-link formation stabilises the elastin precursor so it is primed for elastic fibre assembly.
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Affiliation(s)
- 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
| | - Helena Newandee
- Department of Biomedical Engineering, School of Engineering, University of Connecticut, Storrs-Mansfield, CT 06269-3139, USA
| | - Jennifer Thomson
- 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
| | - Anthony S Weiss
- School of Molecular Bioscience, Bosch Institute, Charles Perkins Centre, The University of Sydney, NSW 2006, Australia
| | - 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.
| | - Anna Tarakanova
- Department of Biomedical Engineering, School of Engineering, University of Connecticut, Storrs-Mansfield, CT 06269-3139, USA; Department of Mechanical Engineering, School of Engineering, University of Connecticut, Storrs-Mansfield, CT 06269-3139, USA.
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11
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Kozel BA, Mecham RP. Elastic fiber ultrastructure and assembly. Matrix Biol 2019; 84:31-40. [PMID: 31669522 DOI: 10.1016/j.matbio.2019.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 09/22/2019] [Accepted: 10/16/2019] [Indexed: 10/25/2022]
Abstract
Studies over the years have described a filamentous structure to mature elastin that suggests a complicated packing arrangement of tropoelastin subunits. The currently accepted mechanism for tropoelastin assembly requires microfibrils to serve as a physical extracellular scaffold for alignment of tropoelastin monomers during and before crosslinking. However, recent evidence suggests that the initial stages of tropoelastin assembly occur within the cell or at unique assembly sites on the plasma membrane where tropoelastin self assembles to form elastin aggregates. Outside the cell, elastin aggregates transfer to growing elastic fibers in the extracellular matrix where tensional forces on microfibrils generated through cell movement help shape the growing fiber. Overall, these observations challenge the widely held idea that interaction between monomeric tropoelastin and microfibrils is a requirement for elastin assembly, and point to self-assembly of tropoelastin as a driving force in elastin maturation.
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Affiliation(s)
- Beth A Kozel
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, Campus Box 8228, 660 South Euclid Ave, St. Louis, MO, 63110, USA.
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12
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Recent updates on the molecular network of elastic fiber formation. Essays Biochem 2019; 63:365-376. [PMID: 31395654 DOI: 10.1042/ebc20180052] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/12/2019] [Accepted: 07/26/2019] [Indexed: 12/20/2022]
Abstract
Elastic fibers confer elasticity and recoiling to tissues and organs and play an essential role in induction of biochemical responses in a cell against mechanical forces derived from the microenvironment. The core component of elastic fibers is elastin (ELN), which is secreted as the monomer tropoelastin from elastogenic cells, and undergoes self-aggregation, cross-linking and deposition on to microfibrils, and assemble into insoluble ELN polymers. For elastic fibers to form, a microfibril scaffold (primarily formed by fibrillin-1 (FBN1)) is required. Numerous elastic fiber-associated proteins are involved in each step of elastogenesis and they instruct and/or facilitate the elastogenesis processes. In this review, we designated five proteins as key molecules in elastic fiber formation, including ELN, FBN1, fibulin-4 (FBLN4), fibulin-5 (FBLN5), and latent TGFβ-binding protein-4 (LTBP4). ELN and FBN1 serve as building blocks for elastic fibers. FBLN5, FBLN4 and LTBP4 have been demonstrated to play crucial roles in elastogenesis through knockout studies in mice. Using these molecules as a platform and expanding the elastic fiber network through the generation of an interactome map, we provide a concise review of elastogenesis with a recent update as well as discuss various biological functions of elastic fiber-associated proteins beyond elastogenesis in vivo.
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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] [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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Mori H, Yamada H, Toyama K, Takahashi K, Akama T, Inoue T, Nakamura T. Developmental and age-related changes to the elastic lamina of Bruch’s membrane in mice. Graefes Arch Clin Exp Ophthalmol 2018; 257:289-301. [DOI: 10.1007/s00417-018-4184-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/10/2018] [Accepted: 11/09/2018] [Indexed: 01/28/2023] Open
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Villain G, Lelievre E, Broekelmann T, Gayet O, Havet C, Werkmeister E, Mecham R, Dusetti N, Soncin F, Mattot V. MAGP
‐1 and fibronectin control
EGFL
7 functions by driving its deposition into distinct endothelial extracellular matrix locations. FEBS J 2018; 285:4394-4412. [DOI: 10.1111/febs.14680] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/31/2018] [Accepted: 10/16/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Gaëlle Villain
- CNRS Institut Pasteur de Lille UMR 8161 – M3T – Mechanisms of Tumorigenesis and Target Therapies Univ. Lille France
| | - Etienne Lelievre
- CNRS Institut Pasteur de Lille UMR 8161 – M3T – Mechanisms of Tumorigenesis and Target Therapies Univ. Lille France
| | - Tom Broekelmann
- Department of Cell Biology and Physiology Washington University School of Medicine St. Louis MO USA
| | - Odile Gayet
- Centre de Recherche en Cancérologie de Marseille (CRCM) INSERM U1068 CNRS UMR 7258 Aix‐Marseille Université and Institut Paoli‐Calmettes, Parc Scientifique et Technologique de Luminy France
| | - Chantal Havet
- CNRS Institut Pasteur de Lille UMR 8161 – M3T – Mechanisms of Tumorigenesis and Target Therapies Univ. Lille France
| | - Elisabeth Werkmeister
- Cellular Microbiology and Physics of Infection Group – Center for Infection and Immunity of Lille CNRS UMR8204 Inserm U1019 CHU Lille Institut Pasteur de Lille Univ. Lille. France
| | - Robert Mecham
- Department of Cell Biology and Physiology Washington University School of Medicine St. Louis MO USA
| | - Nelson Dusetti
- Centre de Recherche en Cancérologie de Marseille (CRCM) INSERM U1068 CNRS UMR 7258 Aix‐Marseille Université and Institut Paoli‐Calmettes, Parc Scientifique et Technologique de Luminy France
| | - Fabrice Soncin
- CNRS Institut Pasteur de Lille UMR 8161 – M3T – Mechanisms of Tumorigenesis and Target Therapies Univ. Lille France
| | - Virginie Mattot
- CNRS Institut Pasteur de Lille UMR 8161 – M3T – Mechanisms of Tumorigenesis and Target Therapies Univ. Lille France
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Muiznieks LD, Sharpe S, Pomès R, Keeley FW. Role of Liquid–Liquid Phase Separation in Assembly of Elastin and Other Extracellular Matrix Proteins. J Mol Biol 2018; 430:4741-4753. [DOI: 10.1016/j.jmb.2018.06.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/29/2018] [Accepted: 06/01/2018] [Indexed: 10/14/2022]
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17
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Fibrillin microfibrils and elastic fibre proteins: Functional interactions and extracellular regulation of growth factors. Semin Cell Dev Biol 2018; 89:109-117. [PMID: 30016650 PMCID: PMC6461133 DOI: 10.1016/j.semcdb.2018.07.016] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 07/04/2018] [Accepted: 07/13/2018] [Indexed: 02/02/2023]
Abstract
Fibrillin microfibrils are extensible polymers that endow connective tissues with long-range elasticity and have widespread distributions in both elastic and non-elastic tissues. They act as a template for elastin deposition during elastic fibre formation and are essential for maintaining the integrity of tissues such as blood vessels, lung, skin and ocular ligaments. A reduction in fibrillin is seen in tissues in vascular ageing, chronic obstructive pulmonary disease, skin ageing and UV induced skin damage, and age-related vision deterioration. Most mutations in fibrillin cause Marfan syndrome, a genetic disease characterised by overgrowth of the long bones and other skeletal abnormalities with cardiovascular and eye defects. However, mutations in fibrillin and fibrillin-binding proteins can also cause short-stature pathologies. All of these diseases have been linked to dysregulated growth factor signalling which forms a major functional role for fibrillin.
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Abstract
Microfibril-associated glycoproteins 1 and 2 (MAGP-1, MAGP-2) are protein components of extracellular matrix microfibrils. These proteins interact with fibrillin, the core component of microfibrils, and impart unique biological properties that influence microfibril function in vertebrates. MAGPs bind active forms of TGFβ and BMPs and are capable of modulating Notch signaling. Mutations in MAGP-1 or MAGP-2 have been linked to thoracic aneurysms and metabolic disease in humans. MAGP-2 has also been shown to be an important biomarker in several human cancers. Mice lacking MAGP-1 or MAGP-2 have defects in multiple organ systems, which reflects the widespread distribution of microfibrils in vertebrate tissues. This review summarizes our current understanding of the function of the MAGPs and their relationship to human disease.
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Affiliation(s)
- Clarissa S Craft
- Division of Bone and Mineral Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Thomas J Broekelmann
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, United States.
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Schrenk S, Cenzi C, Bertalot T, Conconi MT, Di Liddo R. Structural and functional failure of fibrillin‑1 in human diseases (Review). Int J Mol Med 2017; 41:1213-1223. [PMID: 29286095 DOI: 10.3892/ijmm.2017.3343] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 11/29/2017] [Indexed: 11/06/2022] Open
Abstract
Fibrillins (FBNs) are key relay molecules that form the backbone of microfibrils in elastic and non‑elastic tissues. Interacting with other components of the extracellular matrix (ECM), these ubiquitous glycoproteins exert pivotal roles in tissue development, homeostasis and repair. In addition to mechanical support, FBN networks also exhibit regulatory activities on growth factor signalling, ECM formation, cell behaviour and the immune response. Consequently, mutations affecting the structure, assembly and stability of FBN microfibrils have been associated with impaired biomechanical tissue properties, altered cell‑matrix interactions, uncontrolled growth factor or cytokine activation, and the development of fibrillinopathies and associated severe complications in multiple organs. Beyond a panoramic overview of structural cues of the FBN network, the present review will also describe the pathological implications of FBN disorders in the development of inflammatory and fibrotic conditions.
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Affiliation(s)
- Sandra Schrenk
- Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padova, I‑35131 Padova, Italy
| | - Carola Cenzi
- Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padova, I‑35131 Padova, Italy
| | - Thomas Bertalot
- Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padova, I‑35131 Padova, Italy
| | - Maria Teresa Conconi
- Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padova, I‑35131 Padova, Italy
| | - Rosa Di Liddo
- Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padova, I‑35131 Padova, Italy
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20
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Elçin AE, Parmaksiz M, Dogan A, Seker S, Durkut S, Dalva K, Elçin YM. Differential gene expression profiling of human adipose stem cells differentiating into smooth muscle-like cells by TGFβ1/BMP4. Exp Cell Res 2017; 352:207-217. [DOI: 10.1016/j.yexcr.2017.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/02/2017] [Accepted: 02/05/2017] [Indexed: 12/18/2022]
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21
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Unusual life cycle and impact on microfibril assembly of ADAMTS17, a secreted metalloprotease mutated in genetic eye disease. Sci Rep 2017; 7:41871. [PMID: 28176809 PMCID: PMC5296908 DOI: 10.1038/srep41871] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/28/2016] [Indexed: 01/30/2023] Open
Abstract
Secreted metalloproteases have diverse roles in the formation, remodeling, and the destruction of extracellular matrix. Recessive mutations in the secreted metalloprotease ADAMTS17 cause ectopia lentis and short stature in humans with Weill-Marchesani-like syndrome and primary open angle glaucoma and ectopia lentis in dogs. Little is known about this protease or its connection to fibrillin microfibrils, whose major component, fibrillin-1, is genetically associated with ectopia lentis and alterations in height. Fibrillin microfibrils form the ocular zonule and are present in the drainage apparatus of the eye. We show that recombinant ADAMTS17 has unique characteristics and an unusual life cycle. It undergoes rapid autocatalytic processing in trans after its secretion from cells. Secretion of ADAMTS17 requires O-fucosylation and its autocatalytic activity does not depend on propeptide processing by furin. ADAMTS17 binds recombinant fibrillin-2 but not fibrillin-1 and does not cleave either. It colocalizes to fibrillin-1 containing microfibrils in cultured fibroblasts and suppresses fibrillin-2 (FBN2) incorporation in microfibrils, in part by transcriptional downregulation of Fbn2 mRNA expression. RNA in situ hybridization detected Adamts17 expression in specific structures in the eye, skeleton and other organs, where it may regulate the fibrillin isoform composition of microfibrils.
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22
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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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Vassequi-Silva T, Pereira DS, Nery Diez ACC, Braga GG, Godoy JA, Mendes CB, Dos Santos L, Krieger JE, Antunes E, Costa FTM, Vicente CP, Werneck CC. Losartan and captopril treatment rescue normal thrombus formation in microfibril associated glycoprotein-1 (MAGP1) deficient mice. Thromb Res 2015; 138:7-15. [PMID: 26826502 DOI: 10.1016/j.thromres.2015.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/10/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022]
Abstract
INTRODUCTION MAGP1 is a glycoprotein present in the elastic fibers and is a part of the microfibrils components. MAGP1 interacts with von Willebrand factor and the active form of TGF-β and BMP. In mice lacking MAGP1, thrombus formation is delayed, increasing the occlusion time of carotid artery despite presenting normal blood coagulation in vitro. MAGP1-containing microfibrils may play a role in hemostasis and thrombosis. In this work, we evaluated the function of MAGP1 and its relation to TGF-β in the arterial thrombosis process. METHODS AND RESULTS We analyzed thrombus formation time in wild type and MAGP1-deficient mice comparing Rose Bengal and Ferric Chloride induced arterial lesion. The potential participation of TGF-β in this process was accessed when we treated both wild type and MAGP1-deficient mice with losartan (an antihypertensive drug that decreases TGF-β activity) or captopril (an angiotensin converting enzyme inhibitor that was used as a control antihypertensive drug). Besides, we evaluated thrombus embolization and the gelatinolytic activity in the arterial walls in vitro and ex vivo. Losartan and captopril were able to recover the thrombus formation time without changing blood pressure, activated partial thromboplastin time (aPTT), PT (prothrombin time), platelet aggregation and adhesion, but decreased gelatinase activity. CONCLUSIONS Our results suggest that both treatments are effective in the prevention of the sub-endothelial ECM degradation, allowing the recovery of normal thrombus formation.
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Affiliation(s)
| | | | | | - Guilherme G Braga
- Department of Biochemistry and Tissue Biology, State University of Campinas, SP, Brazil
| | - Juliana A Godoy
- Department of Structural and Functional Biology, State University of Campinas, SP, Brazil
| | - Camila B Mendes
- Department of Pharmacology, State University of Campinas, SP, Brazil
| | - Leonardo Dos Santos
- Department of Physiological Sciences, Federal University of Espirito Santo, ES, Brazil
| | - José E Krieger
- Laboratory of Genetic and Molecular Cardiology, InCor-HC/FMUSP, SP, Brazil
| | - Edson Antunes
- Department of Pharmacology, State University of Campinas, SP, Brazil
| | - Fábio T M Costa
- Department of Genetics and Evolution and Bioagents, State University of Campinas, SP, Brazil
| | - Cristina P Vicente
- Department of Structural and Functional Biology, State University of Campinas, SP, Brazil
| | - Claudio C Werneck
- Department of Biochemistry and Tissue Biology, State University of Campinas, SP, Brazil.
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Capuano A, Bucciotti F, Farwell KD, Tippin Davis B, Mroske C, Hulick PJ, Weissman SM, Gao Q, Spessotto P, Colombatti A, Doliana R. Diagnostic Exome Sequencing Identifies a Novel Gene, EMILIN1, Associated with Autosomal-Dominant Hereditary Connective Tissue Disease. Hum Mutat 2015; 37:84-97. [PMID: 26462740 PMCID: PMC4738430 DOI: 10.1002/humu.22920] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 10/05/2015] [Indexed: 12/31/2022]
Abstract
Heritable connective tissue diseases are a highly heterogeneous family of over 200 disorders that affect the extracellular matrix. While the genetic basis of several disorders is established, the etiology has not been discovered for a large portion of patients, likely due to rare yet undiscovered disease genes. By performing trio‐exome sequencing of a 55‐year‐old male proband presenting with multiple symptoms indicative of a connective disorder, we identified a heterozygous missense alteration in exon 1 of the Elastin Microfibril Interfacer 1 (EMILIN1) gene, c.64G>A (p.A22T). The proband presented with ascending and descending aortic aneurysms, bilateral lower leg and foot sensorimotor peripheral neuropathy, arthropathy, and increased skin elasticity. Sanger sequencing confirmed that the EMILIN1 alteration, which maps around the signal peptide cleavage site, segregated with disease in the affected proband, mother, and son. The impaired secretion of EMILIN‐1 in cells transfected with the mutant p.A22T coincided with abnormal protein accumulation within the endoplasmic reticulum. In skin biopsy of the proband, we detected less EMILIN‐1 with disorganized and abnormal coarse fibrils, aggregated deposits underneath the epidermis basal lamina, and dermal cells apoptosis. These findings collectively suggest that EMILIN1 may represent a new disease gene associated with an autosomal‐dominant connective tissue disorder.
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Affiliation(s)
- Alessandra Capuano
- Department of Translational Research, CRO-IRCCS National Cancer Institute, Aviano, 33081, Italy
| | - Francesco Bucciotti
- Department of Translational Research, CRO-IRCCS National Cancer Institute, Aviano, 33081, Italy
| | | | | | | | - Peter J Hulick
- Center for Medical Genetics, NorthShore University HealthSystem, Evanston, Illinois, 60201
| | - Scott M Weissman
- Center for Medical Genetics, NorthShore University HealthSystem, Evanston, Illinois, 60201
| | - Qingshen Gao
- NorthShore Research Institute, NorthShore University HealthSystem, Evanston, Illinois, 60201
| | - Paola Spessotto
- Department of Translational Research, CRO-IRCCS National Cancer Institute, Aviano, 33081, Italy
| | - Alfonso Colombatti
- Department of Translational Research, CRO-IRCCS National Cancer Institute, Aviano, 33081, Italy
| | - Roberto Doliana
- Department of Translational Research, CRO-IRCCS National Cancer Institute, Aviano, 33081, Italy
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The fibrillin microfibril scaffold: A niche for growth factors and mechanosensation? Matrix Biol 2015; 47:3-12. [DOI: 10.1016/j.matbio.2015.05.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/28/2015] [Indexed: 12/22/2022]
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26
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Mecham RP, Gibson MA. The microfibril-associated glycoproteins (MAGPs) and the microfibrillar niche. Matrix Biol 2015; 47:13-33. [PMID: 25963142 DOI: 10.1016/j.matbio.2015.05.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 10/23/2022]
Abstract
The microfibril-associated glycoproteins MAGP-1 and MAGP-2 are extracellular matrix proteins that interact with fibrillin to influence microfibril function. The two proteins are related through a 60 amino acid matrix-binding domain but their sequences differ outside of this region. A distinguishing feature of both proteins is their ability to interact with TGFβ family growth factors, Notch and Notch ligands, and multiple elastic fiber proteins. MAGP-2 can also interact with αvβ3 integrins via a RGD sequence that is not found in MAGP-1. Morpholino knockdown of MAGP-1 expression in zebrafish resulted in abnormal vessel wall architecture and altered vascular network formation. In the mouse, MAGP-1 deficiency had little effect on elastic fibers in blood vessels and lung but resulted in numerous unexpected phenotypes including bone abnormalities, hematopoietic changes, increased fat deposition, diabetes, impaired wound repair, and a bleeding diathesis. Inactivation of the gene for MAGP-2 in mice produced a neutropenia yet had minimal effects on bone or adipose homeostasis. Double knockouts had phenotypes characteristic of each individual knockout as well as several additional traits only seen when both genes are inactivated. A common mechanism underlying all of the traits associated with the knockout phenotypes is altered TGFβ signaling. This review summarizes our current understanding of the function of the MAGPs and discusses ideas related to their role in growth factor regulation.
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Affiliation(s)
- Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Mark A Gibson
- School of Medical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
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Hubmacher D, Apte SS. ADAMTS proteins as modulators of microfibril formation and function. Matrix Biol 2015; 47:34-43. [PMID: 25957949 DOI: 10.1016/j.matbio.2015.05.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 01/17/2023]
Abstract
The ADAMTS (a disintegrin-like and metalloproteinase domain with thrombospondin-type 1 motifs) protein superfamily includes 19 secreted metalloproteases and 7 secreted ADAMTS-like (ADAMTSL) glycoproteins. The possibility of functional linkage between ADAMTS proteins and fibrillin microfibrils was first revealed by a human genetic consilience, in which mutations in ADAMTS10, ADAMTS17, ADAMTSL2 and ADAMTSL4 were found to phenocopy rare genetic disorders caused by mutations affecting fibrillin-1 (FBN1), the major microfibril component in adults. The manifestations of these ADAMTS gene disorders in humans and animals suggested that they participated in the structural and regulatory roles of microfibrils. Whereas two such disorders, Weill-Marchesani syndrome 1 and Weill-Marchesani-like syndrome involve proteases (ADAMTS10 and ADAMTS17, respectively), geleophysic dysplasia and isolated ectopia lentis in humans involve ADAMTSL2 and ADAMTSL4, respectively, which are not proteases. In addition to broadly similar dysmorphology, individuals affected by Weill-Marchesani syndrome 1, Weill-Marchesani-like syndrome or geleophysic dysplasia each show characteristic anomalies suggesting molecule-, tissue-, or context-specific functions for the respective ADAMTS proteins. Ectopia lentis occurs in each of these conditions except geleophysic dysplasia, and is due to a defect in the ciliary zonule, which is predominantly composed of FBN1 microfibrils. Together, this strongly suggests that ADAMTS proteins are involved either in microfibril assembly, stability, and anchorage, or the formation of function-specific supramolecular networks having microfibrils as their foundation. Here, the genetics and molecular biology of this subset of ADAMTS proteins is discussed from the perspective of how they might contribute to fully functional or function-specific microfibrils.
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Affiliation(s)
- Dirk Hubmacher
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA.
| | - Suneel S Apte
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA.
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Hubmacher D, Wang LW, Mecham RP, Reinhardt DP, Apte SS. Adamtsl2 deletion results in bronchial fibrillin microfibril accumulation and bronchial epithelial dysplasia--a novel mouse model providing insights into geleophysic dysplasia. Dis Model Mech 2015; 8:487-99. [PMID: 25762570 PMCID: PMC4415891 DOI: 10.1242/dmm.017046] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 03/05/2015] [Indexed: 12/24/2022] Open
Abstract
Mutations in the secreted glycoprotein ADAMTSL2 cause recessive geleophysic dysplasia (GD) in humans and Musladin–Lueke syndrome (MLS) in dogs. GD is a severe, often lethal, condition presenting with short stature, brachydactyly, stiff skin, joint contractures, tracheal-bronchial stenosis and cardiac valve anomalies, whereas MLS is non-lethal and characterized by short stature and severe skin fibrosis. Although most mutations in fibrillin-1 (FBN1) cause Marfan syndrome (MFS), a microfibril disorder leading to transforming growth factor-β (TGFβ) dysregulation, domain-specific FBN1 mutations result in dominant GD. ADAMTSL2 has been previously shown to bind FBN1 and latent TGFβ-binding protein-1 (LTBP1). Here, we investigated mice with targeted Adamtsl2 inactivation as a new model for GD (Adamtsl2−/− mice). An intragenic lacZ reporter in these mice showed that ADAMTSL2 was produced exclusively by bronchial smooth muscle cells during embryonic lung development. Adamtsl2−/− mice, which died at birth, had severe bronchial epithelial dysplasia with abnormal glycogen-rich inclusions in bronchial epithelium resembling the cellular anomalies described previously in GD. An increase in microfibrils in the bronchial wall was associated with increased FBN2 and microfibril-associated glycoprotein-1 (MAGP1) staining, whereas LTBP1 staining was increased in bronchial epithelium. ADAMTSL2 was shown to bind directly to FBN2 with an affinity comparable to FBN1. The observed extracellular matrix (ECM) alterations were associated with increased bronchial epithelial TGFβ signaling at 17.5 days of gestation; however, treatment with TGFβ-neutralizing antibody did not correct the epithelial dysplasia. These investigations reveal a new function of ADAMTSL2 in modulating microfibril formation, and a previously unsuspected association with FBN2. Our studies suggest that the bronchial epithelial dysplasia accompanying microfibril dysregulation in Adamtsl2−/− mice cannot be reversed by TGFβ neutralization, and thus might be mediated by other mechanisms. Summary: The extracellular protein ADAMTSL2 is a crucial regulator of microfibril composition in the extracellular matrix of bronchial smooth muscle cells and influences bronchial epithelial function.
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Affiliation(s)
- Dirk Hubmacher
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Lauren W Wang
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Dieter P Reinhardt
- Department of Anatomy and Cell Biology and Faculty of Dentistry, McGill University, 3640 University Street, Montreal, Quebec, Canada H3A 0C7
| | - Suneel S Apte
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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Murphy EC, Mörgelin M, Reinhardt DP, Olin AI, Björck L, Frick IM. Identification of molecular mechanisms used by Finegoldia magna to penetrate and colonize human skin. Mol Microbiol 2014; 94:403-17. [PMID: 25164331 PMCID: PMC4241043 DOI: 10.1111/mmi.12773] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2014] [Indexed: 12/27/2022]
Abstract
Finegoldia magna is a Gram-positive anaerobic commensal of the human skin microbiota, but also known to act as an opportunistic pathogen. Two primary virulence factors of F. magna are the subtilisin-like extracellular serine protease SufA and the adhesive protein FAF. This study examines the molecular mechanisms F. magna uses when colonizing or establishing an infection in the skin. FAF was found to be essential in the initial adherence of F. magna to human skin biopsies. In the upper layers of the epidermis FAF mediates adhesion through binding to galectin-7 - a keratinocyte cell marker. Once the bacteria moved deeper into the skin to the basement membrane layer, SufA was found to degrade collagen IV which forms the backbone structure of the basement membrane. It also degraded collagen V, whereby F. magna could reach deeper dermal tissue sites. In the dermis, FAF interacts with collagen V and fibrillin, which presumably helps the bacteria to establish infection in this area. The findings of this study paint a clear picture of how F. magna interacts with human skin and explain how it is such a successful opportunistic pathogen in chronic wounds and ulcers.
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Affiliation(s)
- Elizabeth C Murphy
- Department of Clinical Sciences, Division of Infection Medicine, Lund University, SE-22184, Lund, Sweden
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Sabatier L, Djokic J, Hubmacher D, Dzafik D, Nelea V, Reinhardt DP. Heparin/heparan sulfate controls fibrillin-1, -2 and -3 self-interactions in microfibril assembly. FEBS Lett 2014; 588:2890-7. [DOI: 10.1016/j.febslet.2014.06.061] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/05/2014] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
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Tiedemann K, Boraschi-Diaz I, Rajakumar I, Kaur J, Roughley P, Reinhardt DP, Komarova SV. Fibrillin-1 directly regulates osteoclast formation and function by a dual mechanism. J Cell Sci 2014; 126:4187-94. [PMID: 24039232 DOI: 10.1242/jcs.127571] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mutations in the fibrillin-1 gene give rise to a number of heritable disorders, which are all characterized by various malformations of bone as well as manifestations in other tissues. However, the role of fibrillin-1 in the development and homeostasis of bone is not well understood. Here, we examined the role of fibrillin-1 in regulating osteoclast differentiation from primary bone-marrow-derived precursors and monocytic RAW 264.7 cells. The soluble N-terminal half of fibrillin-1 (rFBN1-N) strongly inhibited osteoclastogenesis, whereas the C-terminal half (rFBN1-C) did not. By contrast, when rFBN1-N was immobilized on calcium phosphate, it did not affect osteoclastogenesis but modulated osteoclast resorptive activity, which was evident by a larger number of smaller resorption pits. Using a panel of recombinant sub-fragments spanning rFBN1-N, we localized an osteoclast inhibitory activity to the 63 kDa subfragment rF23 comprising the N-terminal region of fibrillin-1. Osteoclastic resorption led to the generation of small fibrillin-1 fragments that were similar to those identified in human vertebral bone extracts. rF23, but not rFBN1-N, was found to inhibit the expression of cathepsin K, matrix metalloproteinase 9 and Dcstamp in differentiating osteoclasts. rFBN1-N, but not rF23, exhibited interaction with RANKL. Excess RANKL rescued the inhibition of osteoclastogenesis by rFBN1-N. By contrast, rF23 disrupted RANKL-induced Ca(2+) signaling and activation of transcription factor NFATc1. These studies highlight a direct dual inhibitory role of N-terminal fibrillin-1 fragments in osteoclastogenesis, the sequestration of RANKL and the inhibition of NFATc1 signaling, demonstrating that osteoclastic degradation of fibrillin-1 provides a potent negative feedback that limits osteoclast formation and function.
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Affiliation(s)
- Kerstin Tiedemann
- Faculty of Dentistry, McGill University, 3640 rue University, Montreal, Quebec, Canada, H3A 0C7
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32
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Muiznieks LD, Cirulis JT, van der Horst A, Reinhardt DP, Wuite GJ, Pomès R, Keeley FW. Modulated growth, stability and interactions of liquid-like coacervate assemblies of elastin. Matrix Biol 2014; 36:39-50. [DOI: 10.1016/j.matbio.2014.03.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 11/25/2022]
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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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Abstract
Fibrillins constitute the backbone of extracellular multifunctional assemblies present in elastic and non-elastic matrices, termed microfibrils. Assembly of fibrillins into microfibrils and their homoeostasis is poorly understood and is often compromised in connective tissue disorders such as Marfan syndrome and other fibrillinopathies. Using interaction mapping studies, we demonstrate that fibrillins require the complete gelatin-binding region of fibronectin for interaction, which comprises domains FNI6-FNI9. However, the interaction of fibrillin-1 with the gelatin-binding domain of fibronectin is not involved in fibrillin-1 network assembly mediated by human skin fibroblasts. We show further that the fibronectin network is essential for microfibril homoeostasis in early stages. Fibronectin is present in extracted mature microfibrils from tissue and cells as well as in some in situ microfibrils observed at the ultrastructural level, indicating an extended mechanism for the involvement of fibronectin in microfibril assembly and maturation.
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Zheng Q, Chen S, Chen Y, Lyga J, Wyborski R, Santhanam U. Investigation of age-related decline of microfibril-associated glycoprotein-1 in human skin through immunohistochemistry study. Clin Cosmet Investig Dermatol 2013; 6:317-23. [PMID: 24353434 PMCID: PMC3861293 DOI: 10.2147/ccid.s51958] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
During aging, the reduction of elastic and collagen fibers in dermis can lead to skin atrophy, fragility, and aged appearance, such as increased facial wrinkling and sagging. Microfibril-associated glycoprotein-1 (MAGP-1) is an extracellular matrix protein critical for elastic fiber assembly. It integrates and stabilizes the microfibril and elastin matrix network that helps the skin to endure mechanical stretch and recoil. However, the observation of MAGP-1 during skin aging and its function in the dermis has not been established. To better understand age-related changes in the dermis, we investigated MAGP-1 during skin aging and photoaging, using a combination of in vitro and in vivo studies. Gene expression by microarray was performed using human skin biopsies from young and aged female donors. In addition, immunofluorescence analysis on the MAGP-1 protein was performed in dermal fibroblast cultures and in human skin biopsies. Specific antibodies against MAGP-1 and fibrillin-1 were used to examine protein expression and extracellular matrix structure in the dermis via biopsies from donors of multiple age groups. A reduction of the MAGP-1 gene and protein levels were observed in human skin with increasing age and photoexposure, indicating a loss of the functional MAGP-1 fiber network and a lack of structural support in the dermis. Loss of MAGP-1 around the hair follicle/pore areas was also observed, suggesting a possible correlation between MAGP-1 loss and enlarged pores in aged skin. Our findings demonstrate that a critical “pre-elasticity” component, MAGP-1, declines with aging and photoaging. Such changes may contribute to age-related loss of dermal integrity and perifollicular structural support, which may lead to skin fragility, sagging, and enlarged pores.
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Affiliation(s)
- Qian Zheng
- Global Research and Development, Avon Products Inc., Suffern, New York, USA
| | - Siming Chen
- Global Research and Development, Avon Products Inc., Suffern, New York, USA
| | - Ying Chen
- Global Research and Development, Avon Products Inc., Suffern, New York, USA
| | - John Lyga
- Global Research and Development, Avon Products Inc., Suffern, New York, USA
| | - Russell Wyborski
- Global Research and Development, Avon Products Inc., Suffern, New York, USA
| | - Uma Santhanam
- Global Research and Development, Avon Products Inc., Suffern, New York, USA
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36
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Miao M, Reichheld SE, Muiznieks LD, Huang Y, Keeley FW. Elastin Binding Protein and FKBP65 Modulate in Vitro Self-Assembly of Human Tropoelastin. Biochemistry 2013; 52:7731-41. [DOI: 10.1021/bi400760f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ming Miao
- Research
Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Sean E. Reichheld
- Research
Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Lisa D. Muiznieks
- Research
Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Yayi Huang
- Research
Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Fred W. Keeley
- Department
of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
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Abstract
Elastic fibres are insoluble components of the extracellular matrix of dynamic connective tissues such as skin, arteries, lungs and ligaments. They are laid down during development, and comprise a cross-linked elastin core within a template of fibrillin-based microfibrils. Their function is to endow tissues with the property of elastic recoil, and they also regulate the bioavailability of transforming growth factor β. Severe heritable elastic fibre diseases are caused by mutations in elastic fibre components; for example, mutations in elastin cause supravalvular aortic stenosis and autosomal dominant cutis laxa, mutations in fibrillin-1 cause Marfan syndrome and Weill–Marchesani syndrome, and mutations in fibulins-4 and -5 cause autosomal recessive cutis laxa. Acquired elastic fibre defects include dermal elastosis, whereas inflammatory damage to fibres contributes to pathologies such as pulmonary emphysema and vascular disease. This review outlines the latest understanding of the composition and assembly of elastic fibres, and describes elastic fibre diseases and current therapeutic approaches.
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38
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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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Kaur J, Reinhardt DP. Immobilized metal affinity chromatography co-purifies TGF-β1 with histidine-tagged recombinant extracellular proteins. PLoS One 2012; 7:e48629. [PMID: 23119075 PMCID: PMC3485342 DOI: 10.1371/journal.pone.0048629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 10/03/2012] [Indexed: 01/03/2023] Open
Abstract
Extracellular recombinant proteins are commonly produced using HEK293 cells as histidine-tagged proteins facilitating purification by immobilized metal affinity chromatography (IMAC). Based on gel analyses, this one-step purification typically produces proteins of high purity. Here, we analyzed the presence of TGF-β1 in such IMAC purifications using recombinant extracellular fibrillin-1 fragments as examples. Analysis of various purified recombinant fibrillin-1 fragments by ELISA consistently revealed the presence of picomolar concentrations of active and latent TGF-β1, but not of BMP-2. These quantities of TGF-β1 were not detectable by Western blotting and mass spectrometry. However, the amounts of TGF-β1 were sufficient to consistently trigger Smad2 phosphorylation in fibroblasts. The purification mechanism was analyzed to determine whether the presence of TGF-β1 in these protein preparations represents a specific or non-specific co-purification of TGF-β1 with fibrillin-1 fragments. Control purifications using conditioned medium from non-transfected 293 cells yielded similar amounts of TGF-β1 after IMAC. IMAC of purified TGF-β1 and the latency associated peptide showed that these proteins bound to the immobilized nickel ions. These data clearly demonstrate that TGF-β1 was co-purified by specific interactions with nickel, and not by specific interactions with fibrillin-1 fragments. Among various chromatographic methods tested for their ability to eliminate TGF-β1 from fibrillin-1 preparations, gel filtration under high salt conditions was highly effective. As various recombinant extracellular proteins purified in this fashion are frequently used for experiments that can be influenced by the presence of TGF-β1, these findings have far-reaching implications for the required chromatographic schemes and quality controls.
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Affiliation(s)
- Jasvir Kaur
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - Dieter P. Reinhardt
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Bader HL, Wang LW, Ho JC, Tran T, Holden P, Fitzgerald J, Atit RP, Reinhardt DP, Apte SS. A disintegrin-like and metalloprotease domain containing thrombospondin type 1 motif-like 5 (ADAMTSL5) is a novel fibrillin-1-, fibrillin-2-, and heparin-binding member of the ADAMTS superfamily containing a netrin-like module. Matrix Biol 2012; 31:398-411. [PMID: 23010571 DOI: 10.1016/j.matbio.2012.09.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/13/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
Abstract
ADAMTS-like proteins are related to ADAMTS metalloproteases by their similarity to ADAMTS ancillary domains. Here, we have characterized ADAMTSL5, a novel member of the superfamily with a unique modular organization that includes a single C-terminal netrin-like (NTR) module. Alternative splicing of ADAMTSL5 at its 5' end generates two transcripts that encode different signal peptides, but the same mature protein. These transcripts differ in their translational efficiency. Recombinant ADAMTSL5 is a secreted, N-glycosylated 60kDa glycoprotein located in the subcellular matrix, on the cell-surface, and in the medium of transfected cells. RT-PCR and western blot analysis of adult mouse tissues showed broad expression. Western blot analysis suggested proteolytic release of the NTR module in transfected cells as well as in some mouse tissues. Immunostaining during mouse organogenesis identified ADAMTSL5 in musculoskeletal tissues such as skeletal muscle, cartilage and bone, as well as in many epithelia. Affinity-chromatography demonstrated heparin-binding of ADAMTSL5 through its NTR-module. Recombinant ADAMTSL5 bound to both fibrillin-1 and fibrillin-2, and co-localized with fibrillin microfibrils in the extracellular matrix of cultured fibroblasts, but without discernible effect on microfibril assembly. ADAMTSL5 is the first family member shown to bind both fibrillin-1 and fibrillin-2. Like other ADAMTS proteins implicated in microfibril biology through identification of human and animal mutations, ADAMTSL5 could have a role in modulating microfibril functions.
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Affiliation(s)
- Hannah L Bader
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
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41
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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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42
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43
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Comparative immunolocalization of the elastin fiber-associated proteins fibrillin-1, LTBP-2, and MAGP-1 with components of the collagenous and proteoglycan matrix of the fetal human intervertebral disc. Spine (Phila Pa 1976) 2011; 36:E1365-72. [PMID: 21540769 DOI: 10.1097/brs.0b013e31821fd23e] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A comparative immunolocalization study of elastin-associated proteins and established intervertebral disc (IVD) extracellular matrix (ECM) components. OBJECTIVE To localize for the first time, elastic fiber–associated proteins with structural fibrillar components in the annulus fibrosus (AF) of the fetal IVD. SUMMARY OF BACKGROUND DATA Elastin has been identified histochemically in adult bovine, human, and immature rat IVDs, and in fetal human IVDs using electron microscopy; however, no immunolocalization studies have been undertaken for associated components in human fetal IVDs. METHODS En-bloc fixation of thoracolumbar spinal segments in formalin and Histochoice followed by standard histochemical processing, paraffin embedding, microtome sectioning, and identification of IVD ECM components using a range of specific mono- and polyclonal antibodies and bright-field and laser scanning confocal microscopy. RESULTS The elastic fiber-associated proteins fibrillin-1, LTBP-2, and MAGP-1 were prominently immunolocalized in the outer lamellar layers of the AF of the human fetal IVD. Dual localization of selected components by confocal microscopy demonstrated that versican and LTBP-2 were colocalized with fibrillin-1 microfibrils in the AF lamellae with a similar distribution to the elastin fibers. LTBP-2 was also associated with pericellular perlecan in the outer AF. These interconnections between elastin-associated proteins resulted in an elastic network, which connected the AF cells with the adjacent cartilaginous vertebral bodies. CONCLUSION Specific immunolocalization of fibrillin-1, MAGP-1, and versican with elastin in the outer AF of the fetal human IVD has been demonstrated. We deduce from the established distributions of the elastin-associated proteins and their known interactivities with matrix components that these stabilize and aid in the integration of the elastic fibers in the annular lamellae and may be responsible for the generation of tensional forces in the outer AF, which direct the assembly of this tissue.
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44
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Wang MM. Notch signaling and Notch signaling modifiers. Int J Biochem Cell Biol 2011; 43:1550-62. [PMID: 21854867 DOI: 10.1016/j.biocel.2011.08.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/28/2011] [Accepted: 08/05/2011] [Indexed: 02/07/2023]
Abstract
Originally discovered nearly a century ago, the Notch signaling pathway is critical for virtually all developmental programs and modulates an astounding variety of pathogenic processes. The DSL (Delta, Serrate, LAG-2 family) proteins have long been considered canonical activators of the core Notch pathway. More recently, a wide and expanding network of non-canonical extracellular factors has also been shown to modulate Notch signaling, conferring newly appreciated complexity to this evolutionarily conserved signal transduction system. Here, I review current concepts in Notch signaling, with a focus on work from the last decade elucidating novel extracellular proteins that up- or down-regulate signal potency.
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Affiliation(s)
- Michael M Wang
- Neurology Service, Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA.
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45
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Kirschner R, Hubmacher D, Iyengar G, Kaur J, Fagotto-Kaufmann C, Brömme D, Bartels R, Reinhardt DP. Classical and neonatal Marfan syndrome mutations in fibrillin-1 cause differential protease susceptibilities and protein function. J Biol Chem 2011; 286:32810-23. [PMID: 21784848 DOI: 10.1074/jbc.m111.221804] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in fibrillin-1 give rise to Marfan syndrome (MFS) characterized by vascular, skeletal, and ocular abnormalities. Fibrillins form the backbone of extracellular matrix microfibrils in tissues including blood vessels, bone, and skin. They are crucial for regulating elastic fiber biogenesis and growth factor bioavailability. To compare the molecular consequences of mutations causing the severe neonatal MFS with mutations causing the milder classical MFS, we introduced representative point mutations from each group in a recombinant human fibrillin-1 fragment. Structural effects were analyzed by circular dichroism spectroscopy and analytical gel filtration chromatography. Proteolytic susceptibility was probed with non-physiological and physiological proteases, including plasmin, thrombin, matrix metalloproteinases, and cathepsins. All mutant proteins showed a similar gross secondary structure and no differences in heat stability as compared with the wild-type protein. Proteins harboring neonatal mutations were typically more susceptible to proteolytic cleavage compared with those with classical mutations and the wild-type protein. Proteolytic neo-cleavage sites were found both in close proximity and distant to the mutations, indicating small but significant structural changes exposing cryptic cleavage sites. We also report for the first time that cathepsin K and V cleave non-mutated fibrillin-1 at several domain boundaries. Compared with the classical mutations and the wild type, the group of neonatal mutations more severely affected the ability of fibrillin-1 to interact with heparin/heparan sulfate, which plays a role in microfibril assembly. These results suggest differential molecular pathogenetic concepts for neonatal and classical MFS including enhanced proteolytic susceptibility for physiologically relevant enzymes and loss of function for heparin binding.
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Affiliation(s)
- Ryan Kirschner
- Faculty of Dentistry, Division of Biomedical Sciences, Faculty of Medicine, McGill University, Montreal H3A 2B2, Canada
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Hubmacher D, Sabatier L, Annis DS, Mosher DF, Reinhardt DP. Homocysteine modifies structural and functional properties of fibronectin and interferes with the fibronectin-fibrillin-1 interaction. Biochemistry 2011; 50:5322-32. [PMID: 21561146 DOI: 10.1021/bi200183z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Homocystinuria is a genetic disorder resulting in elevated levels of homocysteine in plasma and tissues. Some of the skeletal and ocular symptoms such as long bone overgrowth, scoliosis, and ectopia lentis overlap with symptoms seen in Marfan syndrome. Marfan syndrome is caused by mutations in the extracellular matrix protein fibrillin-1. We previously showed that fibrillin-1 is a target for homocysteine and that the deposition of homocysteinylated fibrillin-1 in the extracellular matrix is compromised. Since the assembly of fibrillin-1 is critically dependent on fibronectin, we analyzed the consequences of fibronectin homocysteinylation and its interaction with fibrillin-1. Cellular fibronectin and proteolytic fragments were homocysteinylated and tested in various interaction assays with recombinant fibrillin-1 and heparin. Fibronectin homocysteinylation consistently compromised the fibronectin-fibrillin-1 interaction, while the interaction with heparin was not affected. Fibronectin homocysteinylation, but not cysteinylation, reduced the fibronectin dimers to monomers as shown by Western blotting. ELISA analyses of homocysteinylated fibronectin with three monoclonal antibodies demonstrated structural changes in the disulfide-containing FNI domains FNI(2), FNI(4), and FNI(9). Using fluorescently labeled fibronectin, we studied the consequence of fibronectin homocysteinylation on assembly in cell culture. Modified fibronectin showed deficiencies in denovo matrix incorporation and initial assembly. In conclusion, we define here characteristic structural changes of fibronectin upon homocysteinylation that translate into functional deficiencies in the fibronectin-fibrillin-1 interaction and in fibronectin assembly. Since fibronectin is a major organizer of various extracellular protein networks, these structural and functional alterations may contribute to the pathogenesis of homocystinuria and Marfan syndrome.
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Affiliation(s)
- Dirk Hubmacher
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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TB domain proteins: evolutionary insights into the multifaceted roles of fibrillins and LTBPs. Biochem J 2011; 433:263-76. [PMID: 21175431 DOI: 10.1042/bj20101320] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fibrillins and LTBPs [latent TGFβ (transforming growth factor β)-binding proteins] perform vital and complex roles in the extracellular matrix and are relevant to a wide range of human diseases. These proteins share a signature 'eight cysteine' or 'TB (TGFβ-binding protein-like)' domain that is found nowhere else in the human proteome, and which has been shown to mediate a variety of protein-protein interactions. These include covalent binding of the TGFβ propeptide, and RGD-directed interactions with a repertoire of integrins. TB domains are found interspersed with long arrays of EGF (epidermal growth factor)-like domains, which occur more widely in extracellular proteins, and also mediate binding to a large number of proteins and proteoglycans. In the present paper, newly available protein sequence information from a variety of sources is reviewed and related to published findings on the structure and function of fibrillins and LTBPs. These sequences give valuable insight into the evolution of TB domain proteins and suggest that the fibrillin domain organization emerged first, over 600 million years ago, prior to the divergence of Cnidaria and Bilateria, after which it has remained remarkably unchanged. Comparison of sequence features and domain organization in such a diverse group of organisms also provides important insights into how fibrillins and LTBPs might perform their roles in the extracellular matrix.
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Sabatier L, Miosge N, Hubmacher D, Lin G, Davis EC, Reinhardt DP. Fibrillin-3 expression in human development. Matrix Biol 2010; 30:43-52. [PMID: 20970500 DOI: 10.1016/j.matbio.2010.10.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 09/24/2010] [Accepted: 10/13/2010] [Indexed: 11/25/2022]
Abstract
Fibrillin proteins are the major components of extracellular microfibrils found in many connective tissues. Fibrillin-1 and fibrillin-2 are well studied and mutations in these proteins cause a number of fibrillinopathies including Marfan syndrome and congenital contractural arachnodactyly, respectively. Fibrillin-3 was more recently discovered and is much less well characterized. Fibrillin-1 is expressed throughout life, whereas fibrillins-2 and -3 are thought to be primarily present during development. Here, we report detailed fibrillin-3 expression patterns in early human development. A polyclonal antiserum against a C-terminal recombinant half of human fibrillin-3 was produced in rabbit. Anti-fibrillin-3 antibodies were affinity-purified and antibodies cross-reacting with the other fibrillins were removed by absorption resulting in specific anti-fibrillin-3 antibodies. Immunohistochemical analyses with these purified antibodies demonstrate that fibrillin-3 is temporally expressed in numerous tissues relatively evenly from the 6th to the 12th gestational week. Fibrillin-3 was found spatially expressed in perichondrium, perineurium, perimysium, skin, developing bronchi, glomeruli, pancreas, kidney, heart and testis and at the prospective basement membranes in developing epithelia and endothelia. Double immunohistochemical analyses showed that all fibrillins are globally expressed in the same organs, with a number of differences on the tissue level in cartilage, perichondrium and developing bronchi. These results suggest that fibrillin-3, compared to the other fibrillins, fulfills both overlapping and distinct functions in human development.
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Affiliation(s)
- Laetitia Sabatier
- Faculty of Medicine, Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
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Akhtar K, Broekelmann TJ, Miao M, Keeley FW, Starcher BC, Pierce RA, Mecham RP, Adair-Kirk TL. Oxidative and nitrosative modifications of tropoelastin prevent elastic fiber assembly in vitro. J Biol Chem 2010; 285:37396-404. [PMID: 20847053 DOI: 10.1074/jbc.m110.126789] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Elastic fibers are extracellular structures that provide stretch and recoil properties of tissues, such as lungs, arteries, and skin. Elastin is the predominant component of elastic fibers. Tropoelastin (TE), the precursor of elastin, is synthesized mainly during late fetal and early postnatal stages. The turnover of elastin in normal adult tissues is minimal. However, in several pathological conditions often associated with inflammation and oxidative stress, elastogenesis is re-initiated, but newly synthesized elastic fibers appear abnormal. We sought to determine the effects of reactive oxygen and nitrogen species (ROS/RNS) on the assembly of TE into elastic fibers. Immunoblot analyses showed that TE is oxidatively and nitrosatively modified by peroxynitrite (ONOO(-)) and hypochlorous acid (HOCl) and by activated monocytes and macrophages via release of ONOO(-) and HOCl. In an in vitro elastic fiber assembly model, oxidatively modified TE was unable to form elastic fibers. Oxidation of TE enhanced coacervation, an early step in elastic fiber assembly, but reduced cross-linking and interactions with other proteins required for elastic fiber assembly, including fibulin-4, fibulin-5, and fibrillin-2. These findings establish that ROS/RNS can modify TE and that these modifications affect the assembly of elastic fibers. Thus, we speculate that oxidative stress may contribute to the abnormal structure and function of elastic fibers in pathological conditions.
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Affiliation(s)
- Kamal Akhtar
- Departments of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA
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Massam-Wu T, Chiu M, Choudhury R, Chaudhry SS, Baldwin AK, McGovern A, Baldock C, Shuttleworth CA, Kielty CM. Assembly of fibrillin microfibrils governs extracellular deposition of latent TGF beta. J Cell Sci 2010; 123:3006-18. [PMID: 20699357 DOI: 10.1242/jcs.073437] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Control of the bioavailability of the growth factor TGFbeta is essential for tissue formation and homeostasis, yet precisely how latent TGFbeta is incorporated into the extracellular matrix is unknown. Here, we show that deposition of a large latent TGFbeta complex (LLC), which contains latent TGFbeta-binding protein 1 (LTBP-1), is directly dependent on the pericellular assembly of fibrillin microfibrils, which interact with fibronectin during higher-order fibrillogenesis. LTBP-1 formed pericellular arrays that colocalized with microfibrils, whereas fibrillin knockdown inhibited fibrillar LTBP-1 and/or LLC deposition. Blocking alpha5beta1 integrin or supplementing cultures with heparin, which both inhibited microfibril assembly, disrupted LTBP-1 deposition and enhanced Smad2 phosphorylation. Full-length LTBP-1 bound only weakly to N-terminal pro-fibrillin-1, but this association was strongly enhanced by heparin. The microfibril-associated glycoprotein MAGP-1 (MFAP-2) inhibited LTBP-1 binding to fibrillin-1 and stimulated Smad2 phosphorylation. By contrast, fibulin-4, which interacted strongly with full-length LTBP-1, did not induce Smad2 phosphorylation. Thus, LTBP-1 and/or LLC deposition is dependent on pericellular microfibril assembly and is governed by complex interactions between LTBP-1, heparan sulfate, fibrillin-1 and microfibril-associated molecules. In this way, microfibrils control TGFbeta bioavailability.
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Affiliation(s)
- Teresa Massam-Wu
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
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