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Kamma-Lorger CS, Pinali C, Martínez JC, Harris J, Young RD, Bredrup C, Crosas E, Malfois M, Rødahl E, Meek KM, Knupp C. Role of Decorin Core Protein in Collagen Organisation in Congenital Stromal Corneal Dystrophy (CSCD). PLoS One 2016; 11:e0147948. [PMID: 26828927 PMCID: PMC4734740 DOI: 10.1371/journal.pone.0147948] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/11/2016] [Indexed: 11/18/2022] Open
Abstract
The role of Decorin in organising the extracellular matrix was examined in normal human corneas and in corneas from patients with Congenital Stromal Corneal Dystrophy (CSCD). In CSCD, corneal clouding occurs due to a truncating mutation (c.967delT) in the decorin (DCN) gene. Normal human Decorin protein and the truncated one were reconstructed in silico using homology modelling techniques to explore structural changes in the diseased protein. Corneal CSCD specimens were also examined using 3-D electron tomography and Small Angle X-ray diffraction (SAXS), to image the collagen-proteoglycan arrangement and to quantify fibrillar diameters, respectively. Homology modelling showed that truncated Decorin had a different spatial geometry to the normal one, with the truncation removing a major part of the site that interacts with collagen, compromising its ability to bind effectively. Electron tomography showed regions of abnormal stroma, where collagen fibrils came together to form thicker fibrillar structures, showing that Decorin plays a key role in the maintenance of the order in the normal corneal extracellular matrix. Average diameter of individual fibrils throughout the thickness of the cornea however remained normal.
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Affiliation(s)
- Christina S. Kamma-Lorger
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Christian Pinali
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Juan Carlos Martínez
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Jon Harris
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Robert D. Young
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Cecilie Bredrup
- Department of Ophthalmology, Haukeland University Hospital, 5021 Bergen, Norway
| | - Eva Crosas
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Marc Malfois
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Eyvind Rødahl
- Department of Ophthalmology, Haukeland University Hospital, 5021 Bergen, Norway
- Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway
| | - Keith M. Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Carlo Knupp
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
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Bertassoni LE, Swain MV. The contribution of proteoglycans to the mechanical behavior of mineralized tissues. J Mech Behav Biomed Mater 2014; 38:91-104. [DOI: 10.1016/j.jmbbm.2014.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 06/12/2014] [Accepted: 06/14/2014] [Indexed: 10/25/2022]
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Orgel JPRO, Eid A, Antipova O, Bella J, Scott JE. Decorin core protein (decoron) shape complements collagen fibril surface structure and mediates its binding. PLoS One 2009; 4:e7028. [PMID: 19753304 PMCID: PMC2737631 DOI: 10.1371/journal.pone.0007028] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 08/19/2009] [Indexed: 11/18/2022] Open
Abstract
Decorin is the archetypal small leucine rich repeat proteoglycan of the vertebrate extracellular matrix (ECM). With its glycosaminoglycuronan chain, it is responsible for stabilizing inter-fibrillar organization. Type I collagen is the predominant member of the fibrillar collagen family, fulfilling both organizational and structural roles in animal ECMs. In this study, interactions between decoron (the decorin core protein) and binding sites in the d and e1 bands of the type I collagen fibril were investigated through molecular modeling of their respective X-ray diffraction structures. Previously, it was proposed that a model-based, highly curved concave decoron interacts with a single collagen molecule, which would form extensive van der Waals contacts and give rise to strong non-specific binding. However, the large well-ordered aggregate that is the collagen fibril places significant restraints on modes of ligand binding and necessitates multi-collagen molecular contacts. We present here a relatively high-resolution model of the decoron-fibril collagen complex. We find that the respective crystal structures complement each other well, although it is the monomeric form of decoron that shows the most appropriate shape complementarity with the fibril surface and favorable calculated energies of interaction. One molecule of decoron interacts with four to six collagen molecules, and the binding specificity relies on a large number of hydrogen bonds and electrostatic interactions, primarily with the collagen motifs KXGDRGE and AKGDRGE (d and e1 bands). This work helps us to understand collagen-decorin interactions and the molecular architecture of the fibrillar ECM in health and disease.
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Affiliation(s)
- Joseph P R O Orgel
- BioCAT and microCoSM Centres: Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, Illinois, USA.
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Ciarletta P, Ben Amar M. A finite dissipative theory of temporary interfibrillar bridges in the extracellular matrix of ligaments and tendons. J R Soc Interface 2008; 6:909-24. [PMID: 19106068 DOI: 10.1098/rsif.2008.0487] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The structural integrity and the biomechanical characteristics of ligaments and tendons result from the interactions between collagenous and non-collagenous proteins (e.g. proteoglycans, PGs) in the extracellular matrix. In this paper, a dissipative theory of temporary interfibrillar bridges in the anisotropic network of collagen type I, embedded in a ground substance, is derived. The glycosaminoglycan chains of decorin are assumed to mediate interactions between fibrils, behaving as viscous structures that transmit deformations outside the collagen molecules. This approach takes into account the dissipative effects of the unfolding preceding fibrillar elongation, together with the slippage of entire fibrils and the strain-rate-dependent damage evolution of the interfibrillar bridges. Thermodynamic consistency is used to derive the constitutive equations, and the transition state theory is applied to model the rearranging properties of the interfibrillar bridges. The constitutive theory is applied to reproduce the hysteretic spectrum of the tissues, demonstrating how PGs determine damage evolution, softening and non-recoverable strains in their cyclic mechanical response. The theoretical predictions are compared with the experimental response of ligaments and tendons from referenced studies. The relevance of the proposed model in mechanobiology research is discussed, together with several applications from medical practice to bioengineering science.
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Affiliation(s)
- P Ciarletta
- Laboratoire de Physique Statistique de l'Ecole Normale Supérieure, 24 rue Lhomond, Paris Cedex 05, France.
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Lujan TJ, Underwood CJ, Henninger HB, Thompson BM, Weiss JA. Effect of dermatan sulfate glycosaminoglycans on the quasi-static material properties of the human medial collateral ligament. J Orthop Res 2007; 25:894-903. [PMID: 17343278 DOI: 10.1002/jor.20351] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The glycosaminoglycan of decorin, dermatan sulfate (DS), has been suggested to contribute to the mechanical properties of soft connective tissues such as ligaments and tendons. This study investigated the mechanical function of DS in human medial collateral ligaments (MCL) using nondestructive shear and tensile material tests performed before and after targeted removal of DS with chondroitinase B (ChB). The quasi-static elastic material properties of human MCL were unchanged after DS removal. At peak deformation, tensile and shear stresses in ChB treated tissue were within 0.5% (p>0.70) and 2.0% (p>0.30) of pre-treatment values, respectively. From pre- to post-ChB treatment under tensile loading, the tensile tangent modulus went from 242+/-64 to 233+/-57 MPa (p=0.44), and tissue strain at peak deformation went from 4.3+/-0.3% to 4.4+/-0.3% (p=0.54). Tissue hysteresis was unaffected by DS removal for both tensile and shear loading. Biochemical analysis confirmed that 90% of DS was removed by ChB treatment when compared to control samples, and transmission electron microscopy (TEM) imaging further verified the degradation of DS by showing an 88% reduction (p<.001) of sulfated glycosaminoglycans in ChB treated tissue. These results demonstrate that DS in mature knee MCL tissue does not resist tensile or shear deformation under quasi-static loading conditions, challenging the theory that decorin proteoglycans contribute to the elastic material behavior of ligament.
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Affiliation(s)
- Trevor J Lujan
- Department of Bioengineering, University of Utah, 50 South Central Campus Drive, Room 2480, Salt Lake City, UT 84112, USA
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