title: Dense fibrillar collagen matrices to analyse extracellular matrix receptor function.
abstract: OBJECTIVE
  The goal of this study was to understand whether dense fibrillar collagen matrices, with a hierarchical structure resembling native collagen matrices, could be useful to study collagen receptor function, in a more physiological context. The receptor analysed here was integrin α11β1, already shown to be involved in cell attachment and migration on collagen-coated plastic, and also in contraction of loose fibrillar collagen hydrogels.
  
  
  METHODS
  Collagen matrices prepared here corresponded to dense fibrillar hydrogels concentrated at 5mg/ml. The behaviour of α11β1 deficient fibroblasts seeded on these concentrated matrices was assessed in terms of adhesion, morphology and migration, then compared to that observed on classical hydrogels at 1mg/ml, corresponding to loose collagen matrices.
  
  
  RESULTS
  Short-term attachment assays showed disturbed interactions between α11β1 deficient cells and collagen matrices in a concentration-dependent manner. Long-term assays revealed reduced cell spreading of alpha 11(-/-) cells on the dense collagen matrices, associated with a disturbed cytoskeleton network. Moreover, anoikis was observed when alpha 11(-/-) cells were seeded on 5mg/ml matrices, and not on looser 1mg/ml matrices. In scratch wound in vitro assays, carried out with cells on 5mg/ml fibrillar collagen matrices, alpha 11(-/-) cells migrated much better than their wild-type counterparts. In contrast, no significant difference was observed between wild and knock-out cells seeded on plastic.
  
  
  CONCLUSIONS
  The present study demonstrates the validity of in vivo-like dense fibrillar collagen matrices to evaluate cell receptor functions more significantly than with 2D cell cultures or loose hydrogels.
authors.affiliation: CNRS-UMR 7574, laboratoire chimie de la matière condensée, University Pierre and Marie Curie-Paris 6, école pratique des Hautes-Études, 4, place Jussieu, 75005 Paris, France. chelary@snv.jussieu.fr
authors.forename: C
authors.initials: C
authors.lastname: Helary
authors.forename: B
authors.initials: B
authors.lastname: Rodriguez-Sanchez
authors.forename: B
authors.initials: B
authors.lastname: Rodrigues-Sanchez
authors.forename: S
authors.initials: S
authors.lastname: Vigier
authors.forename: M-M
authors.initials: MM
authors.lastname: Giraud Guill
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D004622:Embryo, Mammalian; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D024022:Fibrillar Collagens / Q000378:metabolism / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D016023:Integrins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D038981:Receptors, Collagen / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D024022:Fibrillar Collagens; D016023:Integrins; D011956:Receptors, Cell Surface; D038981:Receptors, Collagen; C052131:extracellular matrix receptor; C467800:integrin alpha11beta1