Ablation of developing podocytes disrupts cellular interactions and nephrogenesis both inside and outside the glomerulus.
Podocyte loss in adults leads to glomerulosclerosis. However, the impact of podocyte loss on glomerulogenesis and the development of the kidney as a whole has not been directly studied. Here, we used a podocyte-specific Cre transgene to direct the production of diphtheria toxin (DTA) inside podocytes during nephrogenesis. Affected podocytes underwent translational arrest and apoptosis, leading to oliguria, proteinuria, hematuria, interstitial hemorrhage, and perinatal death. Glomerular cell-cell interactions were disrupted, even before overt podocyte apoptosis. VEGF production by podocytes was greatly decreased, and this was associated with reduced endothelial fenestration and altered glomerular vascular architecture. In addition to these glomerular anomalies, embryonic podocyte ablation also led to structural changes and increased apoptosis in proximal tubules. The collecting ducts, however, only showed molecular changes that are likely an indirect effect of the greatly reduced urine flow. Although podocyte loss significantly impacted the development and maintenance of the vasculature both inside and outside the glomerulus, our results suggest that there is a lack of long-range signaling from deep-seated, mature glomeruli to the differentiating cells in the outer nephrogenic zone. This study illustrates the tight integration of various cell types in the developing kidney and shows that the impact of podocyte loss during development is much greater than that in adults. This study also shows the specificity and effectiveness of a genetically controlled podocyte ablation system in mice where the additional readily available tools can further expand its applications.
Jia
Qunshan
Q
Dept. of Internal Medicine/Renal Div., Campus Box 8126, Washington Univ. School of Medicine, St. Louis, MO 63110, USA
McDill
Bradley W
BW
Sankarapandian
Bala
B
Wu
Sen
S
Liapis
Helen
H
Holzman
Lawrence B
LB
Capecchi
Mario R
MR
Miner
Jeffrey H
JH
Chen
Feng
F
D000818:Animals; D017209:Apoptosis; D001485:Basement Membrane / Q000473:pathology; D017931:DNA Primers; D003643:Death; D004167:Diphtheria Toxin / Q000096:biosynthesis; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D007678:Kidney Glomerulus / Q000473:pathology / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D050199:Podocytes / Q000473:pathology / Q000502:physiology* / Q000648:ultrastructure; D011507:Proteinuria / Q000473:pathology
D017931:DNA Primers; D004167:Diphtheria Toxin; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein