This work has been financially supported by the FIS/FEDER (PI12/01080 to M.F.F., PI11/01728 to AF.F. and PI12/02587 to C.L.L.), the ISCIII (CP11/00131 to A.F.F.), the IUOPA (to R.M.R.), the FICYT (to E.G.T.), the Red de Investigación Renal (REDinREN) (to C.L.L.), and the Ramon Areces Foundation (to M.F.F.). The IUOPA is supported by the Obra Social Cajastur, Spain.