Inducible Overexpression of sFlt-1 in Podocytes Ameliorates Glomerulopathy in Diabetic Mice
Ching-Hsin Ku 1 ,
Kathryn E. White 2 ,
Alessandra Dei Cas 1 ,
Anthea Hayward 1 ,
Zoe Webster 3 ,
Rudy Bilous 2 ,
Sally Marshall 2 ,
Giancarlo Viberti 1 and
Luigi Gnudi 1
1 Cardiovascular Division, King's College London School of Medicine, Guy's Hospital, King's College London, London, U.K
2 Department of Diabetes and Metabolism, School of Clinical Medical Sciences, University of Newcastle, Newcastle, U.K
3 Medical Research Council, Imperial College School of Medicine, Hammersmith Hospital, Imperial College, London, U.K
Corresponding author: Luigi Gnudi, luigi.gnudi{at}kcl.ac.uk
Abstract
OBJECTIVE— Podocyte-specific, doxycycline (DOX)-inducible overexpression of soluble vascular endothelial growth factor (VEGF) receptor-1
(sFlt-1) in adult mice was used to investigate the role of the VEGF-A/VEGF receptor (VEGFR) system in diabetic glomerulopathy.
RESEARCH DESIGN AND METHODS— We studied nondiabetic and diabetic transgenic mice and wild-type controls treated with vehicle (VEH) or DOX for 10 weeks.
Glycemia was measured by a glucose-oxidase method and blood pressure by a noninvasive technique. sFlt-1, VEGF-A, VEGFR2, and
nephrin protein expression in renal cortex were determined by Western immunoblotting; urine sFlt-1, urine free VEGF-A, and
albuminuria by enzyme-linked immunosorbent assay; glomerular ultrastructure by electron microscopy; and VEGFR1 and VEGFR2
cellular localization with Immunogold techniques.
RESULTS— Nondiabetic DOX-treated transgenic mice showed a twofold increase in cortex sFlt-1 expression and a fourfold increase in sFlt-1
urine excretion ( P < 0.001). Urine free VEGF-A was decreased by 50%, and cortex VEGF-A expression was upregulated by 30% ( P < 0.04). VEGFR2 expression was unchanged, whereas its activation was reduced in DOX-treated transgenic mice ( P < 0.02). Albuminuria and glomerular morphology were similar among groups. DOX-treated transgenic diabetic mice showed a 60%
increase in 24-h urine sFlt-1 excretion and an ∼70% decrease in urine free VEGF-A compared with VEH-treated diabetic mice
( P < 0.04) and had lower urine albumin excretion at 10 weeks than VEH-treated diabetic ( d ) mice: d -VEH vs. d -DOX, geometric mean (95% CI), 117.5 (69–199) vs. 43 (26.8–69) μg/24 h ( P = 0.003). Diabetes-induced mesangial expansion, glomerular basement membrane thickening, podocyte foot-process fusion, and
transforming growth factor-β1 expression were ameliorated in DOX-treated diabetic animals ( P < 0.05). Diabetes-induced VEGF-A and nephrin expression were not affected in DOX-treated mice.
CONCLUSIONS— Podocyte-specific sFlt-1 overexpression ameliorates diabetic glomerular injury, implicating VEGF-A in the pathogenesis of
this complication.
Footnotes
Published ahead of print at http://diabetes.diabetesjournals.org on 22 July 2008.
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Inducible Overexpression of sFlt-1 in Podocytes Ameliorates Glomerulopathy in Diabetic Mice

10.2337/db08-0647