Dense fibrillar collagen matrices to analyse extracellular matrix receptor function

Abstract

AimThe 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. Materials and methodsCollagen 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. ResultsShort-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. ConclusionsThe 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.