title: Glycosaminoglycans show a specific periodic interaction with type I collagen fibrils.
abstract: Current wisdom on intermolecular interactions in the extracellular matrix assumes that small proteoglycans bind collagen fibrils on highly specific sites via their protein core, while their carbohydrate chains interact with each other in the interfibrillar space. The present study used high-resolution scanning electron microscopy to analyse the interaction of two small leucine-rich proteoglycans and several glycosaminoglycan chains with type I collagen fibrils obtained in vitro in a controlled, cell-free environment. Our results show that most ligands directly influence the collagen fibril size and shape, and their aggregation into thicker bundles. All chondroitin sulphate/dermatan sulphate glycosaminoglycans we tested, except chondroitin 4-sulphate, bound to the fibril surface in a highly specific way and, even in the absence of any protein core, formed regular, periodic interfibrillar links resembling those of the intact proteoglycan. Only intact decorin, however, was able to organize collagen fibrils into fibres compact enough to mimic in vitro the superfibrillar organization of natural tissues. Our data indicate that multiple interaction patterns may exist in vivo, may explain why decorin- or biglycan-knockout organisms show milder effects than can be expected, and may lead to the development of better, simpler engineered biomaterials.
authors.affiliation: Department of Human Anatomy, Insubria University, Varese, Italy. mario.raspanti@uninsubria.it
authors.forename: Mario
authors.initials: M
authors.lastname: Raspanti
authors.forename: Manuela
authors.initials: M
authors.lastname: Viola
authors.forename: Antonella
authors.initials: A
authors.lastname: Forlino
authors.forename: Ruggero
authors.initials: R
authors.lastname: Tenni
authors.forename: Cristian
authors.initials: C
authors.lastname: Gruppi
authors.forename: Maria Enrica
authors.initials: ME
authors.lastname: Tira
mesh_terms: D000818:Animals; D001665:Binding Sites; D001672:Biocompatible Materials / Q000737:chemistry; D002417:Cattle; D002809:Chondroitin Sulfates / Q000378:metabolism; D024042:Collagen Type I / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D003871:Dermatan Sulfate / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D012867:Skin / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D024042:Collagen Type I; D006025:Glycosaminoglycans; D003871:Dermatan Sulfate; D002809:Chondroitin Sulfates