PURPOSE: To investigate the suppressive effect of nitric oxide (NO) on vascular endothelial growth factor (VEGF) gene expression and to elucidate its mechanism of action. METHODS: Immortalized human retinal epithelial (RPE) cells, H-ras-transfected murine capillary endothelial cells, and nuclear factor-kappaB (NF-kappaB) RelA knockout 3T3 fibroblasts had VEGF gene expression stimulated by hypoxia, TPA (phorbol ester 12-O-tetradecanoylphorbol-13 acetate), and ras-transfection. The dose response and time course of inhibition of VEGF gene expression by NO were characterized by northern blot analysis, ribonuclease protection assay, and enzyme-linked immunosorbent assay. The effects of NF-kappaB and cGMP in the NO-induced suppression of VEGF gene expression were quantitated. cGMP production was inhibited by LY 83583 (6-anilino-5,8-quinolinedione), a specific inhibitor of guanylate cyclase production, and cGMP accumulation was quantitated by immunoassay. RelA knockout 3T3 fibroblasts were used to assess the contribution of NF-kappaB to the downregulation of VEGF by NO. RESULTS: The NO donor sodium nitroprusside (SNP) decreased hypoxia-induced VEGF gene expression in a dose- and time-dependent manner. One hundred fifty micromolar SNP completely suppressed hypoxia-induced VEGF mRNA levels for at least 24 hours. Constitutive VEGF expression was not altered by SNP. The SNP-mediated decreases in VEGF expression were associated with increases in intracellular cGMP and were blocked by LY 83583. Sodium nitroprusside was able to decrease hypoxia-induced VEGF mRNA increases in fibroblasts deficient in the RelA subunit of NF-kappaB. Nitric oxide was also effective at suppressing increased VEGF expression secondan, to mutant ras and TPA. CONCLUSIONS: These data indicate that NO decreases hypoxia-induced VEGF via a cGMP-dependent mechanism and suggest that NO may serve as an endogenous inhibitor of both hypoxia- and non- hypoxia-enhanced VEGF expression in vivo.
PURPOSE: To investigate the suppressive effect of nitric oxide (NO) on vascular endothelial growth factor (VEGF) gene expression and to elucidate its mechanism of action. METHODS: Immortalized human retinal epithelial (RPE) cells, H-ras-transfected murine capillary endothelial cells, and nuclear factor-kappaB (NF-kappaB) RelA knockout 3T3 fibroblasts had VEGF gene expression stimulated by hypoxia, TPA (phorbol ester 12-O-tetradecanoylphorbol-13 acetate), and ras-transfection. The dose response and time course of inhibition of VEGF gene expression by NO were characterized by northern blot analysis, ribonuclease protection assay, and enzyme-linked immunosorbent assay. The effects of NF-kappaB and cGMP in the NO-induced suppression of VEGF gene expression were quantitated. cGMP production was inhibited by LY 83583 (6-anilino-5,8-quinolinedione), a specific inhibitor of guanylate cyclase production, and cGMP accumulation was quantitated by immunoassay. RelA knockout 3T3 fibroblasts were used to assess the contribution of NF-kappaB to the downregulation of VEGF by NO. RESULTS: The NO donorsodium nitroprusside (SNP) decreased hypoxia-induced VEGF gene expression in a dose- and time-dependent manner. One hundred fifty micromolar SNP completely suppressed hypoxia-induced VEGF mRNA levels for at least 24 hours. Constitutive VEGF expression was not altered by SNP. The SNP-mediated decreases in VEGF expression were associated with increases in intracellular cGMP and were blocked by LY 83583. Sodium nitroprusside was able to decrease hypoxia-induced VEGF mRNA increases in fibroblasts deficient in the RelA subunit of NF-kappaB. Nitric oxide was also effective at suppressing increased VEGF expression secondan, to mutant ras and TPA. CONCLUSIONS: These data indicate that NO decreases hypoxia-induced VEGF via a cGMP-dependent mechanism and suggest that NO may serve as an endogenous inhibitor of both hypoxia- and non- hypoxia-enhanced VEGF expression in vivo.
Authors: Vassiliki Poulaki; Wenying Qin; Antonia M Joussen; Peter Hurlbut; Stanley J Wiegand; John Rudge; George D Yancopoulos; Anthony P Adamis Journal: J Clin Invest Date: 2002-03 Impact factor: 14.808
Authors: Hui Ying Zhang; De Wu Han; Ai Rong Su; Li Tong Zhang; Zhong Fu Zhao; Jing Quan Ji; Bao Hong Li; Cheng Ji Journal: World J Gastroenterol Date: 2007-12-21 Impact factor: 5.742
Authors: Salvador Mérida; Vincent M Villar; Amparo Navea; Carmen Desco; María Sancho-Tello; Cristina Peris; Francisco Bosch-Morell Journal: Front Physiol Date: 2020-05-14 Impact factor: 4.566