TY - JOUR
T1 - Autocrine VEGF-A system in podocytes regulates podocin and its interaction with CD2AP
AU - Guan, Fangxia
AU - Villegas, Guillermo
AU - Teichman, Jason
AU - Mundel, Peter
AU - Tufro, Alda
PY - 2006
Y1 - 2006
N2 - Vascular endothelial growth factor (VEGF-A) signaling is required for endothelial cell differentiation, vasculogenesis, angiogenesis, and vascular patterning. During kidney morphogenesis, podocyte VEGF-A guides endothelial cells toward developing glomeruli. Podocyte VEGF-A expression continues throughout life but its function after completion of development remains unclear. Here, we examined the expression of VEGF-A and its receptors VEGFR1, VEGFR2, NP1, and NP2 in conditionally immortalized mouse podocytes cultured in undifferentiated and differentiated conditions using RT-PCR and Western analysis. VEGF-A secretion was assessed by ELISA and Western analysis. Upon podocyte differentiation, VEGF-A protein expression and secretion increased threefold. Differentiated podocytes expressed eightfold higher VEGFR2 mRNA levels than undifferentiated podocytes, whereas VEGFR1, sVEGFR1, NP1, and NP2 mRNA levels were similar. We examined the regulation and function of the VEGF-A system by exposing differentiated podocytes to recombinant VEGF165 (20 ng/ml) or control media for 24 h. VEGF165 induced a twofold increase in VEGFR2 mRNA and protein levels, whereas VEGFR1, sVEGFR1, NP1, and NP2 mRNA levels remained unchanged. VEGF165 induced VEGFR2 phosphorylation. VEGF165 reduced podocyte apoptosis ∼40%, whereas anti-VEGFR2 neutralizing antibody enhanced it two-fold. We determined that VEGF-A signaling regulates slit diaphragm proteins by inducing a dose-response podocin upregulation and increasing its interaction with CD2AP. The data indicate that podocytes in culture have a functional autocrine VEGF-A system that is regulated by differentiation and ligand availability. VEGF-A functions in podocytes include promoting survival through VEGFR2, inducing podocin upregulation and increasing podocin/CD2AP interaction.
AB - Vascular endothelial growth factor (VEGF-A) signaling is required for endothelial cell differentiation, vasculogenesis, angiogenesis, and vascular patterning. During kidney morphogenesis, podocyte VEGF-A guides endothelial cells toward developing glomeruli. Podocyte VEGF-A expression continues throughout life but its function after completion of development remains unclear. Here, we examined the expression of VEGF-A and its receptors VEGFR1, VEGFR2, NP1, and NP2 in conditionally immortalized mouse podocytes cultured in undifferentiated and differentiated conditions using RT-PCR and Western analysis. VEGF-A secretion was assessed by ELISA and Western analysis. Upon podocyte differentiation, VEGF-A protein expression and secretion increased threefold. Differentiated podocytes expressed eightfold higher VEGFR2 mRNA levels than undifferentiated podocytes, whereas VEGFR1, sVEGFR1, NP1, and NP2 mRNA levels were similar. We examined the regulation and function of the VEGF-A system by exposing differentiated podocytes to recombinant VEGF165 (20 ng/ml) or control media for 24 h. VEGF165 induced a twofold increase in VEGFR2 mRNA and protein levels, whereas VEGFR1, sVEGFR1, NP1, and NP2 mRNA levels remained unchanged. VEGF165 induced VEGFR2 phosphorylation. VEGF165 reduced podocyte apoptosis ∼40%, whereas anti-VEGFR2 neutralizing antibody enhanced it two-fold. We determined that VEGF-A signaling regulates slit diaphragm proteins by inducing a dose-response podocin upregulation and increasing its interaction with CD2AP. The data indicate that podocytes in culture have a functional autocrine VEGF-A system that is regulated by differentiation and ligand availability. VEGF-A functions in podocytes include promoting survival through VEGFR2, inducing podocin upregulation and increasing podocin/CD2AP interaction.
KW - Apoptosis
KW - Cell differentiation
KW - Slit diaphragm proteins
KW - VEGF receptor 2
KW - VEGF-A secretion
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U2 - 10.1152/ajprenal.00448.2005
DO - 10.1152/ajprenal.00448.2005
M3 - Article
C2 - 16597608
AN - SCOPUS:33746610964
SN - 1931-857X
VL - 291
SP - F422-F428
JO - American Journal of Physiology - Renal Physiology
JF - American Journal of Physiology - Renal Physiology
IS - 2
ER -