SMAD3 and glomerulosclerosis: The effect of Smad pathway in proliferative (including pauci-immune GN and lupus nephritis III, IV) and non-proliferative GN was examined and demonstrated that pSmad 2/3 was increased in all glomerular cells and was positively correlated with serum creatinine level and interstitial inflammation in both GN.58 A recent study evaluated the role of Smad3 as an important mediator of glomerulosclerosis and interstitial fibrosis in a model of proliferative crescentic GN.