Browsing by Author "Martin, Rody San"

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    D-Glucose stimulation of L-arginine transport and nitric oxicle synthesis results from activation of mitogen-activated protein kinases p42/44 and smad2 requiring functional type II TGF-beta receptors in human umbilical vein endothelium
    (WILEY, 2007) Vasquez, Rodrigo; Farias, Marcelo; Vega, Jost Luis; Martin, Rody San; Vecchiola, Andrea; Casanello, Paola; Sobrevia, Luis
    Elevated extracellular D-glucose increases transforming growth factor P I (TGF-P 1) release from human umbilical vein endothelium (HUVEC). TGF-P 1, via TGF-P receptors I (T beta RI) and T beta RII, activates Smad2 and mitogen -activated protein kinases p44 and p42 (p42/44 (mapk)). We studied whether D-glucose-stimulation Of L-arginine transport and nitric oxide synthesis involves TGF-beta 1 in primary cultures of HUVEC. TGF-P I release was higher (similar to 1.6-fold) in 25 mM (high) compared with 5 mM (normal) D-glucose. TGF-P I increases L-arginine transport (half maximal effect similar to 1.6 ng/ml) in normal D-glucose, but did not alter high D-glucose-increased L-arginine transport. TGF-P I and high D-glucose increased hCAT- I mRNA expression (similar to 8-fold) and maximal transport velocity (V-max), L- [(3) H]citrulline formation from L- [3 H]arginine (index of NO synthesis) and endothelial NO synthase (eNOS) protein abundance, but did not alter eNOS phosphorylation. TGF-beta 1 I and high D-gludose increased p42/44 mapk and Smad2 phosphorylation, an effect blocked by PD-98059 (MEK 1 /2 inhibitor). However, TGF-P I and high D-glucose were ineffective in cells expressing a truncated, negative dominant T beta RII High D-glucose increases L-arginine transport and eNOS expression following T beta RII activation by TGF-P I involving p42/44 (mapk) and Smad2 in HUVEC. Thus, TGF-P I could play a crucial role under conditions of hyperglycemia, such as gestational diabetes mellitus, which is
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    Nitric oxide reduces adenosine transporter ENT1 gene (SLC29A1) promoter activity in human fetal endotheliurn from gestational diabetes
    (WILEY, 2006) Farias, Marcelo; Martin, Rody San; Puebla, Carlos; Pearson, Jeremy D.; Casado, Javier F.; Pastor Anglada, Marcal; Casanello, Paola; Sobrevia, Luis
    Human umbilical vein endothelial cells (HUVEC) from gestational diabetes exhibit reduced adenosine uptake and increased nitric oxide (NO) synthesis. Adenosine transport via human equilibrative nucleoside transporters 1 (hENT1) is reduced by NO by unknown mechanisms in HUVEC. We examined whether gestational diabetes-reduced adenosine transport results from lower hENT1 gene (SLC29A1) expression. HUVEC from gestational diabetes exhibit reduced SLC29A1 promoter activity when transfected with pGL3-hENT1(-2154) compared with pGL3-hENT1(-1114) constructs, an effect blocked by N-G-nitro-L-arginine methyl ester (L-NAME, NOS inhibitor), but unaltered by S-nitroso-N-acetyl-L,D-penicillamine (SNAP, NO donor). In cells from gestational diabetes transfected with pGL3-hENT1(-2114), L-NAME increased, but SNAP did not alter promoter activity and hENT1 expression. However, in cells from normal pregnancies L-NAME increased, but SNAP reduced promoter activity and hENT1 expression. Adenovirus-silenced eNOS expression increased hENT1 expression and activity in cells from normal or gestational diabetic pregnancies. Thus, reduced adenosine transport may result from downregulation of SLC29A1 expression by NO in HUVEC from gestational diabetes. These findings explain the accumulation of extracellular adenosine detected in cultures of HUVEC from gestational diabetes. In addition, fetal endothelial dysfunction could be involved in the abnormal fetal development and growth seen in gestational diabetes.