Contribution of collagen adhesion receptors to tissue fibrosis.

Fibrosis is the result of a wound-healing response that fails to restore normal tissue structure function. One of the critical hallmarks of fibrosis is disrupted collagen remodeling. In tissue homeostasis, the production, deposition and organization of collagen is balanced by the degradation and remodeling of collagen within the existing matrix. After injury or chronic infection, tissues initiate a wound-healing response that is intended to create a new ECM for restoring tissue structure and function. If the wound-healing response is dysregulated or if the tissue injury or infection is severe or long-lasting, collagen deposition exceeds collagen degradation and the tissue repair process leads to fibrosis. The fibrotic repair response is extraordinarily complex and involves a wide spectrum of cells, signaling pathways and regulatory systems, some of which can be readily disrupted and thereby contribute to fibrotic lesions. The dysregulated collagen remodeling is a common end-point of all fibrotic disorders, and one of the rate-limiting steps of collagen remodeling is the binding of cells to collagen fibrils by specific cell adhesion receptors. In this review, we describe how the expression and function of collagen adhesion receptors contribute to collagen processing events that contribute to tissue fibrosis. Graphical abstract Balance between collagen remodeling in health and disease.