Cooperative signaling between integrins and growth factor receptors in fibrosis.

Fibrosis is a pathological process characterized by accumulation of fibrous connective tissue in organs, leading to organ malfunction and failure. At the cellular level, tissue injury or cellular stress results in aberrant and/or sustained fibroblast "activation" leading to excessive extracellular matrix (ECM) accumulation and remodeling, as well as abnormal crosstalk with other cell types. Fibroblast functions within the fibrotic milieu are broad and complex, but among the most prominent are regulation of tissue architecture via modulation of ECM deposition and synthesis, and production of, activation of, and response to growth factors. Thus, both integrins and growth factor receptors (GFRs) play critical roles in fibroblast orchestration of tissue remodeling. However, the interplay between integrins and GFRs in this context is not fully understood. Their interaction has been described for other diseases, such as cancer. Here, we review the literature relevant to integrin/GFR interactions in the context of fibrosis, classify the known interactions into broad categories, and discuss research opportunities that may yield novel therapeutic targets for a broad range of debilitating chronic diseases.