Modulation of notch-1 signaling alleviates vascular endothelial growth factor-mediated diabetic nephropathy.
OBJECTIVE
Disturbances in podocytes are typically associated with marked proteinuria, a hallmark of diabetic nephropathy. This study was conducted to investigate modulation of Notch-1 signaling in high glucose (HG)-stressed human podocytes and in a diabetic animal model.


METHODS
Expression of the Notch signaling components was examined in HG-treated podocytes, human embryonic kidney cells (HEK293), and kidneys from diabetic animals by RT-qPCR, Western blot analysis, and immunohistochemical staining. The association between the Notch signaling, VEGF expression, and podocyte integrity was evaluated.


RESULTS
Notch-1 signaling was significantly activated in HG-cultured human podocytes and HEK293 cells and kidneys from diabetic animals. HG also augmented VEGF expression, decreasing nephrin expression and podocyte number-a critical event for the development of proteinuria in diabetic nephropathy. After use of pharmacological modulators or specific shRNA knockdown strategies, inhibition of Notch-1 signaling significantly abrogated VEGF activation and nephrin repression in HG-stressed cells and ameliorated proteinuria in the diabetic kidney.


CONCLUSIONS
Our findings suggest that upregulation of Notch-1 signaling in HG-treated renal podocytes induces VEGF expression and subsequent nephrin repression and apoptosis. Modulation of Notch-1 signaling may hold promise as a novel therapeutic strategy for the treatment of diabetic nephropathy.
Lin
Chun-Liang
CL
Department of Nephrology, Chang Gung Memorial Hospital atChiayi, Chiayi, Taiwan. linchunliang@adm.cgmh.org.tw
Wang
Feng-Sheng
FS
Hsu
Yen-Chen
YC
Chen
Cheng-Nan
CN
Tseng
Min-Jen
MJ
Saleem
Moin A
MA
Chang
Pey-Jium
PJ
Wang
Jeng-Yi
JY
D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D017931:DNA Primers; D003928:Diabetic Nephropathies / Q000503:physiopathology*; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D007668:Kidney / Q000502:physiology; D010957:Plasmids; D050199:Podocytes / Q000166:cytology / Q000502:physiology; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D034622:RNA Interference; D051381:Rats; D051881:Receptor, Notch1 / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*
D017931:DNA Primers; D051881:Receptor, Notch1; D042461:Vascular Endothelial Growth Factor A; D012313:RNA; D053829:Amyloid Precursor Protein Secretases; D005947:Glucose