A murine model of Denys-Drash syndrome reveals novel transcriptional targets of WT1 in podocytes.
The Wilms tumor-suppressor gene WT1, a key player in renal development, also has a crucial role in maintenance of the glomerulus in the mature kidney. However, molecular pathways orchestrated by WT1 in podocytes, where it is highly expressed, remain unknown. Their defects are thought to modify the cross-talk between podocytes and other glomerular cells and ultimately lead to glomerular sclerosis, as observed in diffuse mesangial sclerosis (DMS) a nephropathy associated with WT1 mutations. To identify podocyte WT1 targets, we generated a novel DMS mouse line, performed gene expression profiling in isolated glomeruli and identified excellent candidates that may modify podocyte differentiation and growth factor signaling in glomeruli. Scel, encoding sciellin, a protein of the cornified envelope in the skin, and Sulf1, encoding a 6-O endosulfatase, are shown to be expressed in wild-type podocytes and to be strongly down-regulated in mutants. Co-expression of Wt1, Scel and Sulf1 was also found in a mesonephric cell line, and siRNA-mediated knockdown of WT1 decreased Scel and Sulf1 mRNAs and proteins. By ChIP we show that Scel and Sulf1 are direct WT1 targets. Cyp26a1, encoding an enzyme involved in the degradation of retinoic acid, is shown to be up-regulated in mutant podocytes. Cyp26a1 may play a role in the development of glomerular lesions but does not seem to be regulated by WT1. These results provide novel clues in our understanding of normal glomerular function and early events involved in glomerulosclerosis.
Inserm, U574, Hôpital Necker-Enfants Malades, Paris, France.
Julien
J
Ratelade
Christelle
C
Arrondel
Ghislaine
G
Hamard
Serge
S
Garbay
Scott
S
Harvey
Nathalie
N
Biebuyck
Herbert
H
Schulz
Nick
N
Hastie
Marco
M
Pontoglio
Marie-Claire
MC
Gubler
Corinne
C
Antignac
Laurence
L
Heidet
D000483:Alleles; D000818:Animals; D002460:Cell Line; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D030321:Denys-Drash Syndrome / Q000201:enzymology / Q000235:genetics*; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006579:Heterozygote; D007678:Kidney Glomerulus / Q000201:enzymology / Q000473:pathology; D008650:Mesonephros / Q000201:enzymology; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation / Q000235:genetics; D050199:Podocytes / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D034443:RNA Transport; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D000072516:Retinoic Acid 4-Hydroxylase; D015238:Sulfotransferases / Q000235:genetics; D014158:Transcription, Genetic; D025721:WT1 Proteins / Q000378:metabolism*
D025721:WT1 Proteins; D003577:Cytochrome P-450 Enzyme System; C000607080:Cyp26a1 protein, mouse; D000072516:Retinoic Acid 4-Hydroxylase; C486773:Sulf1 protein, mouse; D015238:Sulfotransferases