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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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Renal cortex VEGF-A protein expression and VEGFR2 phosphorylation in podocyte-specific sFlt-1 overexpressing diabetic mice after 10 weeks of treatment with VEH or DOX. Nondiabetic control mice treated with VEH are reported for comparison. A: Representative Western immunoblotting and densitometry quantitative analysis of renal cortex VEGF-A expression expressed as % change over nondiabetic VEH-treated mice. VEGF-A protein was significantly upregulated in diabetic VEH-treated mice by 30% over VEH-treated control animals (*P = 0.02 for c-VEH vs. d-VEH). No differences in VEGF-A expression were observed between VEH- or DOX-treated diabetic mice (n = 5–9/group). B: Densitometry quantitative analysis of phosphorylated [Tyr(951)] VEGFR2 over total VEGFR2 in kidney cortex lysate expressed as % change over nondiabetic VEH-treated mice. VEGFR2 phosphorylation was significantly raised in diabetic VEH-treated mice by 58% over VEH-treated control animals (*P = 0.01 for c-VEH vs. d-VEH). No differences were observed between VEH- or DOX-treated diabetic mice (n = 5–6/group).
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f5: Renal cortex VEGF-A protein expression and VEGFR2 phosphorylation in podocyte-specific sFlt-1 overexpressing diabetic mice after 10 weeks of treatment with VEH or DOX. Nondiabetic control mice treated with VEH are reported for comparison. A: Representative Western immunoblotting and densitometry quantitative analysis of renal cortex VEGF-A expression expressed as % change over nondiabetic VEH-treated mice. VEGF-A protein was significantly upregulated in diabetic VEH-treated mice by 30% over VEH-treated control animals (*P = 0.02 for c-VEH vs. d-VEH). No differences in VEGF-A expression were observed between VEH- or DOX-treated diabetic mice (n = 5–9/group). B: Densitometry quantitative analysis of phosphorylated [Tyr(951)] VEGFR2 over total VEGFR2 in kidney cortex lysate expressed as % change over nondiabetic VEH-treated mice. VEGFR2 phosphorylation was significantly raised in diabetic VEH-treated mice by 58% over VEH-treated control animals (*P = 0.01 for c-VEH vs. d-VEH). No differences were observed between VEH- or DOX-treated diabetic mice (n = 5–6/group).

Mentions: Renal cortex VEGF-A protein expression was significantly upregulated as expected in diabetic VEH-administered mice compared with nondiabetic VEH-administered mice (control [c]-VEH vs. d-VEH, P = 0.02); DOX treatment did not induce any change in VEGF-A expression in diabetic mice (Fig. 5A).


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)

Renal cortex VEGF-A protein expression and VEGFR2 phosphorylation in podocyte-specific sFlt-1 overexpressing diabetic mice after 10 weeks of treatment with VEH or DOX. Nondiabetic control mice treated with VEH are reported for comparison. A: Representative Western immunoblotting and densitometry quantitative analysis of renal cortex VEGF-A expression expressed as % change over nondiabetic VEH-treated mice. VEGF-A protein was significantly upregulated in diabetic VEH-treated mice by 30% over VEH-treated control animals (*P = 0.02 for c-VEH vs. d-VEH). No differences in VEGF-A expression were observed between VEH- or DOX-treated diabetic mice (n = 5–9/group). B: Densitometry quantitative analysis of phosphorylated [Tyr(951)] VEGFR2 over total VEGFR2 in kidney cortex lysate expressed as % change over nondiabetic VEH-treated mice. VEGFR2 phosphorylation was significantly raised in diabetic VEH-treated mice by 58% over VEH-treated control animals (*P = 0.01 for c-VEH vs. d-VEH). No differences were observed between VEH- or DOX-treated diabetic mice (n = 5–6/group).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2551695&req=5

f5: Renal cortex VEGF-A protein expression and VEGFR2 phosphorylation in podocyte-specific sFlt-1 overexpressing diabetic mice after 10 weeks of treatment with VEH or DOX. Nondiabetic control mice treated with VEH are reported for comparison. A: Representative Western immunoblotting and densitometry quantitative analysis of renal cortex VEGF-A expression expressed as % change over nondiabetic VEH-treated mice. VEGF-A protein was significantly upregulated in diabetic VEH-treated mice by 30% over VEH-treated control animals (*P = 0.02 for c-VEH vs. d-VEH). No differences in VEGF-A expression were observed between VEH- or DOX-treated diabetic mice (n = 5–9/group). B: Densitometry quantitative analysis of phosphorylated [Tyr(951)] VEGFR2 over total VEGFR2 in kidney cortex lysate expressed as % change over nondiabetic VEH-treated mice. VEGFR2 phosphorylation was significantly raised in diabetic VEH-treated mice by 58% over VEH-treated control animals (*P = 0.01 for c-VEH vs. d-VEH). No differences were observed between VEH- or DOX-treated diabetic mice (n = 5–6/group).
Mentions: Renal cortex VEGF-A protein expression was significantly upregulated as expected in diabetic VEH-administered mice compared with nondiabetic VEH-administered mice (control [c]-VEH vs. d-VEH, P = 0.02); DOX treatment did not induce any change in VEGF-A expression in diabetic mice (Fig. 5A).

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