Ford BM, Eid AA, Göőz M, Barnes JL, Gorin YC, Abboud HE. ADAM17 mediates Nox4 expression and NADPH oxidase activity in the kidney cortex of OVE26 mice. Am J Physiol Renal Physiol 305: F323-F332, 2013. First published May 15, 2013 doi:10.1152/ajprenal.00522.2012.-Matrix protein accumulation is a prominent feature of diabetic nephropathy that contributes to renal fibrosis and decline in renal function. The pathogenic mechanisms of matrix accumulation are incompletely characterized. We investigated if the matrix metalloprotease a disintegrin and metalloprotease1 7 (ADAM17), known to cleave growth factors and cytokines, is activated in the kidney cortex of OVE26 type 1 diabetic mice and the potential mechanisms by which ADAM17 mediates extracellular matrix accumulation. Protein expression and activity of ADAM17 were increased in OVE26 kidney cortex. Using a pharmacological inhibitor to ADAM17, TMI-005, we determined that ADAM17 activation results in increased type IV collagen, Nox4, and NADPH oxidase activity in the kidney cortex of diabetic mice. In cultured mouse proximal tubular epithelial cells (MCTs), high glucose increases ADAM17 activity, Nox4 and fibronectin expression, cellular collagen content, and NADPH oxidase activity. These effects of glucose were inhibited when cells were pretreated with TMI-005 and/or transfected with small interfering ADAM17. Collectively, these data indicate a novel mechanism whereby hyperglycemia in diabetes increases extracellular matrix protein expression in the kidney cortex through activation of ADAM17 and enhanced oxidative stress through Nox enzyme activation. Additionally, our study is the first to provide evidence that Nox4 is downstream of ADAM17. ADAM17; Nox4; diabetic nephropathy; OVE26 mice; extracellular matrix DIABETIC NEPHROPATHY (DN) is characterized by diverse pathophysiological changes in the kidney including extracellular matrix (ECM) accumulation in glomeruli and tubulointerstitium (50). Matrix metalloproteases (MMPs) are a large and diverse family of proteins implicated in regulating ECM turnover and tissue remodeling. Several studies have suggested that metalloproteases contribute to ECM turnover in diabetes. However, relatively little information is available regarding the role of the a disintegrin and a metalloprotease, or ADAM, family of MMPs. Members of this family are modular membrane proteins involved in proteolytic processing or shedding of membrane-bound proteins and receptors (24,25,32,43). ADAM metalloproteases have adhesive and proteolytic properties that modulate cell signaling and biological responses of cells (5,12,19). ADAM17, a member of this ADAM family of MMPs, was originally described as the sheddase of tumor necrosis factor-␣, referred to as TNF␣-converting enzyme (4, 34). In addition, ADAM17 is also responsible for cleaving membrane-bound growth factors and receptors such as transforming growth factor-␣ (TGF␣), heparin-bound epidermal growth factor (HB-EGF), TNF receptor I and II, adhesion molecules, proinflammatory molecules, amyloid pr...