Inducible Overexpression of sFlt-1 in Podocytes Ameliorates Glomerulopathy in Diabetic Mice

• Published in: Diabetes (New York, N.Y.) Vol. 57; no. 10; pp. 2824 - 2833
• Main Authors: KU, Ching-Hsin, WHITE, Kathryn E, DEI CAS, Alessandra, HAYWARD, Anthea, WEBSTER, Zoe, BILOUS, Rudy, MARSHALL, Sally, VIBERTI, Giancarlo, GNUDI, Luigi
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01-10-2008
• Subjects: Animals; Biological and medical sciences; Blotting, Western; Complications; Complications and side effects; Diabetes; Diabetes Complications - genetics; Diabetes Complications - metabolism; Diabetes Complications - pathology; Diabetes mellitus; Diabetes Mellitus - genetics; Diabetes Mellitus - metabolism; Diabetes Mellitus - pathology; Diabetes. Impaired glucose tolerance; Diabetic Nephropathies - genetics; Diabetic Nephropathies - metabolism; Diabetic Nephropathies - pathology; Doxycycline; Doxycycline - pharmacology; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Enzyme-Linked Immunosorbent Assay; Enzymes; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Gene Expression - drug effects; Growth factor receptors; Humans; Kidney Glomerulus - metabolism; Kidney Glomerulus - pathology; Kidney Glomerulus - ultrastructure; Kinases; Laboratory animals; Medical sciences; Membrane Proteins - metabolism; Mice; Mice, Transgenic; Microscopy; Microscopy, Electron; Pathogenesis; Physiological aspects; Podocytes - cytology; Podocytes - drug effects; Podocytes - metabolism; Proteins; Research design; Transgenic animals; Urine; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - metabolism; Vascular Endothelial Growth Factor Receptor-1 - genetics; Vascular Endothelial Growth Factor Receptor-1 - metabolism; Vascular Endothelial Growth Factor Receptor-2 - metabolism; United Kingdom > UK; Endocrinopathy; Podocyte; Vertebrata; Mammalia; Mouse; Animal; Diabetes mellitus; Rodentia; Gene overexpression
• ISSN: 0012-1797; 1939-327X
• DOI: 10.2337/db08-0647

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.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work
is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore
be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Accepted July 12, 2008.
Received May 15, 2008.
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