Reactive oxygen species (ROS) initiate multiple pathological and physiological cellular responses, including tyrosine phosphorylation of proteins. In this study, we investigated the effects of ROS on cell-extracellular matrix interactions utilizing the floating three-dimensional collagen gel assay. Exposure of mesangial cells grown in three-dimensional culture to H2O2, 3-amino-1,2,4-triazole (a catalase inhibitor), or puromycin is associated with gel reorganization accompanied by tyrosine phosphorylation of multiple proteins, including focal adhesion kinase (FAK). Neutrophils cocultured with mesangial cells in three-dimensional culture also induce mesangial cell-collagen gel reorganization and initiate tyrosine phosphorylation of a similar set of proteins. Collectively, these results show that ROS of either endogenous or exogenous origin can modulate mesangial cell-extracellular matrix interactions through initiation of a phosphotyrosine kinase signaling cascade. Consequently, ROS may play a role as signaling molecules that regulate mesangial cell-extracellular matrix interactions in both physiological and pathological conditions.
