Blocking Wnt secretion by gene deletion of Wls in renal tubules significantly inhibits myofibroblast activation and reduces renal fibrosis following unilateral ureteral obstruction. Blocking Wnt secretion in renal tubules (rather than in fibroblasts) suppresses fibroblast activation and reduces renal fibrosis following injury. The gene discussed is WLS; the disease is Ureteral obstruction.