SMAD3 and liver dysplastic nodule: Regarding DN, in streptozotocin (STZ)-induced DN models, mice lacking Smad3 were found to avoid renal fibrosis, including glomerular basement membrane (GBM) thickening and excessive extracellular matrix (ECM) production (Fujimoto et al., 2003), although the suppression of albuminuria was consistently observed (Wang et al., 2007).