Evaluation of metanephric maturation in a human fetal kidney explant model.
We have developed a unique human fetal kidney explant model to study the role of the insulin-like growth factor (IGF) system in metanephric development. Kidneys from 10-18 wk gestation human abortuses were maintained in serum-free conditions and defined medium, which was shown to support the induction and differentiation of the viable metanephric blastema. Histologically the tissue remained viable to 192 h of serum-free culture, while metanephric differentiation, reflected by a shrinking nephrogenic zone and the formation of maturing S-shape and glomerular forms, was accelerated and occurred between 48 and 96 h. In the nephrogenic zone, a significant decrease in IGF-II gene expression occurred, which reflected the differentiation of the metanephric blastema cell mass, IGF-II expression persisted, however, in the expanded interstitial mesenchyme. With differentiation over 48 h an increase in IGFBP-2 and WT1 gene expression by Northern blot analysis occurred, and was localized by in situ hybridization to the differentiating glomerular epithelial cell mass. Analysis of the explant-conditioned media by Western ligand blot demonstrated an increase in the rate of IGF binding protein (IGFBP)-2 peptide production by the differentiating explant, consistent with an increase in IGFBP-2 gene expression and with metanephric differentiation. This pattern of temporal and spatial gene expression closely approximates that of normal in vivo fetal renal development and of glomerular epithelial cell differentiation.
Matsell
D G
DG
Department of Pediatrics, Anatomy and Cell Biology, University of Western Ontario, London, Canada.
Bennett
T
T
D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000235:genetics; D005069:Evaluation Studies as Topic; D015870:Gene Expression; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000096:biosynthesis; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D007668:Kidney / Q000196:embryology* / Q000378:metabolism / Q000473:pathology; D008954:Models, Biological; D009924:Organ Culture Techniques; D051762:PAX2 Transcription Factor; D014157:Transcription Factors / Q000235:genetics; D025721:WT1 Proteins
D004268:DNA-Binding Proteins; D018971:Insulin-Like Growth Factor Binding Protein 2; D018974:Insulin-Like Growth Factor Binding Protein 4; D051762:PAX2 Transcription Factor; C497318:PAX2 protein, human; D014157:Transcription Factors; D025721:WT1 Proteins; D007335:Insulin-Like Growth Factor II