NOX expression and function in kidney fibrosis. NOXs constitute a major source of ROS in the kidney. Renal NOXs modulate a variety of cell functions that are involved in kidney fibrosis such as inflammation, ECM deposition, myofibroblast differentiation/contraction, and EndMT. Renal NOXs have also been shown to regulate vascular tone, hemodynamics, inflammation, and remodeling. EndMT, endothelial to mesenchymal; SOD, superoxide dismutase. Color images are available online.