The integrin-collagen connection - a glue for tissue repair?

Abstract

The α1ß1, α2ß1, α10ß1 and α11ß1 integrins constitute a subset of the integrin family with affinity for GFOGER-like sequences in collagens. Integrins α1ß1 and α2ß1 were originally identified on a subset of activated T-cells, and have since been found to be expressed on a number of cell types including platelets (α2ß1), vascular cells (α1ß1, α2ß1), epithelial cells (α1ß1, α2ß1) and fibroblasts (α1ß1, α2ß1). Integrin α10ß1 shows a distribution that is restricted to mesenchymal stem cells and chondrocytes, whereas integrin α11ß1 appears restricted to mesenchymal stem cells and subsets of fibroblasts. The bulk of the current literature suggests that collagen-binding integrins only have a limited role in adult connective tissue homeostasis, partly due to a limited availability of cell-binding sites in the mature fibrillar collagen matrices. However, some recent data suggest that, instead, they are more crucial for dynamic connective tissue remodeling events - such as wound healing - where theymight act specifically to remodel and restore the tissue architecture. This Commentary discusses the recent development in the field of collagen-binding integrins, their roles in physiological and pathological settings with special emphasis on wound healing, fibrosis and tumor-stroma interactions, and include a discussion of themost recently identified newcomers to this subfamily - integrins α10ß1 and α11ß1.