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Inducible overexpression of sFlt-1 in podocytes ameliorates glomerulopathy in diabetic mice.

Ku CH, White KE, Dei Cas A, Hayward A, Webster Z, Bilous R, Marshall S, Viberti G, Gnudi L - Diabetes (2008)

Bottom Line: Urine free VEGF-A was decreased by 50%, and cortex VEGF-A expression was upregulated by 30% (P < 0.04).Diabetes-induced mesangial expansion, glomerular basement membrane thickening, podocyte foot-process fusion, and transforming growth factor-beta1 expression were ameliorated in DOX-treated diabetic animals (P < 0.05).Podocyte-specific sFlt-1 overexpression ameliorates diabetic glomerular injury, implicating VEGF-A in the pathogenesis of this complication.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular Division, King's College London School of Medicine, Guy's Hospital, King's College London, London, 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 approximately 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) mug/24 h (P = 0.003). Diabetes-induced mesangial expansion, glomerular basement membrane thickening, podocyte foot-process fusion, and transforming growth factor-beta1 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.

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Mesangial expansion in podocyte sFlt-1 overexpressing control nondiabetic and diabetic mice after 10 weeks of treatment with VEH or DOX. A: Quantitative electron microscopy of VvMes in control and diabetic mice treated with VEH or DOX (n = 6–8/group). VvMes was increased in VEH-treated diabetic mice (*P = 0.003 for c-VEH vs. d-VEH). Treatment with DOX significantly reduced VvMes in diabetic mice (#P = 0.04 for d-VEH vs. d-DOX) but had no effect in nondiabetic control animals. B: Representative images on transmission electron microscopy show amelioration of glomerular mesangial expansion in DOX-treated diabetic mice compared with VEH-treated diabetic animals. Scale bars represent 5 μm.
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f7: Mesangial expansion in podocyte sFlt-1 overexpressing control nondiabetic and diabetic mice after 10 weeks of treatment with VEH or DOX. A: Quantitative electron microscopy of VvMes in control and diabetic mice treated with VEH or DOX (n = 6–8/group). VvMes was increased in VEH-treated diabetic mice (*P = 0.003 for c-VEH vs. d-VEH). Treatment with DOX significantly reduced VvMes in diabetic mice (#P = 0.04 for d-VEH vs. d-DOX) but had no effect in nondiabetic control animals. B: Representative images on transmission electron microscopy show amelioration of glomerular mesangial expansion in DOX-treated diabetic mice compared with VEH-treated diabetic animals. Scale bars represent 5 μm.

Mentions: Mesangial volume fraction (VvMes) was increased in VEH-administered diabetic mice compared with VEH-administered control animals (c-VEH vs. d-VEH, 0.16 ± 0.1 vs. 0.22 ± 0.01, P = 0.003). Administration of DOX significantly reduced VvMes in the diabetic mice (d-VEH vs. d-DOX, 0.22 ± 0.01 vs. 0.18 ± 0.01, P = 0.04) but had no effect in the control mice (c-VEH vs. c-DOX, 0.16 ± 0.01 vs. 0.17 ± 0.01) (Fig. 7A and B).


Inducible overexpression of sFlt-1 in podocytes ameliorates glomerulopathy in diabetic mice.

Ku CH, White KE, Dei Cas A, Hayward A, Webster Z, Bilous R, Marshall S, Viberti G, Gnudi L - Diabetes (2008)

Mesangial expansion in podocyte sFlt-1 overexpressing control nondiabetic and diabetic mice after 10 weeks of treatment with VEH or DOX. A: Quantitative electron microscopy of VvMes in control and diabetic mice treated with VEH or DOX (n = 6–8/group). VvMes was increased in VEH-treated diabetic mice (*P = 0.003 for c-VEH vs. d-VEH). Treatment with DOX significantly reduced VvMes in diabetic mice (#P = 0.04 for d-VEH vs. d-DOX) but had no effect in nondiabetic control animals. B: Representative images on transmission electron microscopy show amelioration of glomerular mesangial expansion in DOX-treated diabetic mice compared with VEH-treated diabetic animals. Scale bars represent 5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2551695&req=5

f7: Mesangial expansion in podocyte sFlt-1 overexpressing control nondiabetic and diabetic mice after 10 weeks of treatment with VEH or DOX. A: Quantitative electron microscopy of VvMes in control and diabetic mice treated with VEH or DOX (n = 6–8/group). VvMes was increased in VEH-treated diabetic mice (*P = 0.003 for c-VEH vs. d-VEH). Treatment with DOX significantly reduced VvMes in diabetic mice (#P = 0.04 for d-VEH vs. d-DOX) but had no effect in nondiabetic control animals. B: Representative images on transmission electron microscopy show amelioration of glomerular mesangial expansion in DOX-treated diabetic mice compared with VEH-treated diabetic animals. Scale bars represent 5 μm.
Mentions: Mesangial volume fraction (VvMes) was increased in VEH-administered diabetic mice compared with VEH-administered control animals (c-VEH vs. d-VEH, 0.16 ± 0.1 vs. 0.22 ± 0.01, P = 0.003). Administration of DOX significantly reduced VvMes in the diabetic mice (d-VEH vs. d-DOX, 0.22 ± 0.01 vs. 0.18 ± 0.01, P = 0.04) but had no effect in the control mice (c-VEH vs. c-DOX, 0.16 ± 0.01 vs. 0.17 ± 0.01) (Fig. 7A and B).

Bottom Line: Urine free VEGF-A was decreased by 50%, and cortex VEGF-A expression was upregulated by 30% (P < 0.04).Diabetes-induced mesangial expansion, glomerular basement membrane thickening, podocyte foot-process fusion, and transforming growth factor-beta1 expression were ameliorated in DOX-treated diabetic animals (P < 0.05).Podocyte-specific sFlt-1 overexpression ameliorates diabetic glomerular injury, implicating VEGF-A in the pathogenesis of this complication.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular Division, King's College London School of Medicine, Guy's Hospital, King's College London, London, 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 approximately 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) mug/24 h (P = 0.003). Diabetes-induced mesangial expansion, glomerular basement membrane thickening, podocyte foot-process fusion, and transforming growth factor-beta1 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.

Show MeSH
Related in: MedlinePlus