Il-1 Beta Enhances Cell Adhesion To Degraded Fibronectin

IL-1 beta is a prominent proinflammatory cytokine that mediates degradation of extracellular matrix proteins through increased expression of matrix metalloproteinases, which involves a signaling pathway in adherent cells that is restricted by focal adhesions. Currently, the mechanism by which IL-1 beta affects cell adhesion to matrix proteins is not defined, and it is not known whether degraded matrix proteins affect IL-1 beta signaling. We examined adhesion-related IL-1 beta signaling in fibroblasts attaching to native or MMP3-degraded fibronectin. IL-1 beta increased cell attachment, resistance to shear force and the numbers of focal adhesions containing activated beta(1) integrins. IL-1 beta-enhanced attachment required FAK, kindlins 1/2, and talin. MMP3-degraded fibronectin-inhibited IL-1 beta-enhanced cell adhesion and promoted spontaneous ERK activation that was independent of IL-1 beta treatment. We conclude that IL-1 beta enhances the adhesion of anchorage-dependent cells to MMP3-degraded fibronectin, which, in turn, is associated with deregulated cellular responses to IL-1 beta. These data point to a novel role of IL-1 beta as a proadhesive signaling molecule in inflammation that employs kindlins and talin to regulate adhesion.-Rajshankar, D., Downey, G. P., McCulloch, C. A. IL-1 beta enhances cell adhesion to degraded fibronectin. FASEB J. 26, 4429-4444 (2012). www.fasebj.org