Integrins, adhesion, and cardiac remodeling.

Integrins are heterodimeric cell surface receptors that mediate a cell's ability to perceive its environment, respond to changed in its environment, and alter its environment. When activated, these receptors form focal adhesions, which are areas of close attachment of the cells to extracellular matrix proteins in which colocalization of cytoskeletal proteins, intracellular signaling molecules, and growth factor receptors occurs. In cardiac fibroblasts, integrins mediate cell growth and adhesion. Growth factors such as angiotensin II regulate DNA synthesis, protooncogene expression, extracellular matrix production, adhesion, and other actions of cardiac fibroblasts, many of which require integrin activation. In addition to controlling growth factor and hemodynamic effects, regulation ofintegrin activity may be useful to affect cardiac fibrosis and the remodeling process.