Abstract
Our previous studies using puromycin aminonucleoside (PAN) established that podocyte damage leads to glomerular growth arrest during development and glomerulosclerosis later in life. This study examined the potential benefit of maintaining podocyte-derived VEGF in podocyte defense and survival after PAN injury using conditional transgenic podocytes and mice, in which human VEGF-A (hVEGF) transgene expression is controlled by tetracycline responsive element (TRE) promoter and reverse tetracycline transactivator (rtTA) in podocytes. In vitro experiments used primary cultured podocytes harvested from mice carrying podocin-rtTA and TRE-hVEGF transgenes, in which hVEGF can be induced selectively. Induction of VEGF in PAN-exposed podocytes resulted in preservation of intrinsic VEGF, α-actinin-4 and synaptopodin, antiapoptotic marker Bcl-xL/Bax, as well as attenuation in apoptotic marker cleaved/total caspase-3. In vivo, compared with genotype controls, PAN-sensitive neonatal mice with physiologically relevant levels of podocyte-derived VEGF showed significantly larger glomeruli. Furthermore, PAN-induced up-regulation of desmin, down-regulation of synaptopodin and nephrin, and disruption of glomerular morphology were significantly attenuated in VEGF-induced transgenic mice. Our data indicate that podocyte-derived VEGF provides self-preservation functions, which can rescue the cell after injury and preempt subsequent deterioration of the glomerulus in developing mice.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Actinin / metabolism
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Animals
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Animals, Newborn
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Apoptosis
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Autocrine Communication
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Caspase 3 / metabolism
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Cells, Cultured
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Desmin / metabolism
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Disease Models, Animal
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Doxycycline / pharmacology
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Glomerulonephritis / chemically induced
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Glomerulonephritis / genetics
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Glomerulonephritis / metabolism
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Glomerulonephritis / pathology
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Glomerulonephritis / prevention & control*
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Humans
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Intracellular Signaling Peptides and Proteins / genetics
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Kidney Glomerulus / metabolism*
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Kidney Glomerulus / pathology
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mice
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Mice, Inbred C57BL
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Mice, Transgenic
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Microfilament Proteins / metabolism
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Podocytes / metabolism*
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Podocytes / pathology
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Puromycin Aminonucleoside*
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Response Elements / drug effects
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Vascular Endothelial Growth Factor A / biosynthesis*
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Vascular Endothelial Growth Factor A / genetics
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Vascular Endothelial Growth Factor A / metabolism
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bcl-2-Associated X Protein / metabolism
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bcl-X Protein / metabolism
Substances
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Actn4 protein, mouse
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Bax protein, mouse
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Bcl2l1 protein, mouse
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Desmin
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Intracellular Signaling Peptides and Proteins
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Membrane Proteins
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Microfilament Proteins
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NPHS2 protein
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Synpo protein, mouse
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VEGFA protein, human
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Vascular Endothelial Growth Factor A
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bcl-2-Associated X Protein
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bcl-X Protein
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nephrin
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vascular endothelial growth factor A, mouse
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Actinin
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Puromycin Aminonucleoside
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Casp3 protein, mouse
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Caspase 3
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Doxycycline