Browsing by Author "Casanello, P."
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- ItemEquilibrative nucleoside transporter 1 expression is downregulated by hypoxia in human umbilical vein endothelium(2005) Casanello, P.; Torres, A.; Sanhueza, F.; González, M.; Farías, M.; Gallardo, V.; Pastor-Anglada, M.; San Martín, R.; Sobrevía Luarte, Luis AlbertoReduced oxygen level (hypoxia) induces endothelial dysfunction and release of the endogenous nucleosideadenosine. Human umbilical vein endothelium (HUVEC) function in an environment with 3% to 5% O2and exhibitefficient adenosine membrane transport via human equilibrative nucleoside transporters 1 (hENT1). We studied whetheradenosine transport and hENT1 expression are altered by hypoxia in HUVEC. Hypoxia (0 to 24 hours, 2% and 1% O2)reduced maximal hENT1-adenosine transport velocity (Vmax) and maximal nitrobenzylthionosine (NBMPR, a high-affinity hENT1 protein ligand) binding, but increased extracellular adenosine concentration. Hypoxia also reducedhENT1 protein and mRNA levels, effects unaltered byN_x0001_-nitro-L-arginine methyl ester (L-NAME, nitric oxide synthase[NOS] inhibitor) or PD-98059 (inhibitor of mitogen-activated protein kinase kinase 1 and 2 [MEK1/2]). Hypoxiareduced endothelial NOS (eNOS) activity and eNOS phosphorylation at Ser1177, but increased eNOS protein level.Hypoxia increased (1 to 3 hours), but reduced (24 hours) p42/44mapkphosphorylation. Thus, hypoxia-increasedextracellular adenosine may result from reduced hENT1-adenosine transport in HUVEC. Hypoxia effect seems not toinvolve NO, but p42/44mapkmay be required for the relatively rapid effect (1 to 3 hours) of hypoxia. These results couldbe important in diseases where the fetus is exposed to intrauterine environments poor in oxygen, such as intrauterinegrowth restriction, or where adenosine transport is altered, such as gestational diabetes.
- ItemHuman equilibrative nucleoside transporters 1 and 2 may be differentially modulated by A(2B) adenosine receptors in placenta microvascular endothelial cells from pre-eclampsia(W B SAUNDERS CO LTD, 2008) Escudero, C.; Casanello, P.; Sobrevia, L.Pre-eclampsia is associated with elevated maternal blood pressure and proteinuria, altered fetal growth, and increased plasma adenosine concentration in the mother and the fetus. Human equilibrative nucleoside transporters 1 (hENT1) and hENT2 are crucial to maintain physiological plasma levels of adenosine, thus modulating its several biological effects through adenosine receptor activation. However, it is unknown whether hENTs and adenosine receptors are expressed in human placental microvascular endothelium (hPMEC). To assay whether the increased fetal plasma adenosine concentration in pre-eclampsia results from altered hENT-mediated transport, and the potential involvement of adenosine receptors in this phenomenon, we investigated hENTs and A(2A) and A(2B) adenosine receptors expression and function in hPMEC. Cells were isolated and Cultured from normal pregnancies (n = 17) or Pre-eclampsia with adequate-for-gestational age fetuses (n = 7). hENT1, hENT2, A(2A) and A(2B) adenosine receptors were expressed and functional in hPMEC. Extracelhilar adenosine concentration was higher (4-fold) in pre-eclampsia versus normal pregnancies. hPMEC from pre-eclampsia exhibit increased total ;transport (hENT1 + hENT2), and maximal velocity (V-max) for hENT2- (2-fold), but reduced V-max for hENT1-mediated adenosine transport (75%), with no changes in apparent K-m. hENT2 expression was increased (4.5-fold), but hENT1 protein abundance was reduced (80%) in pre-eclampsia. Equally, A2A expression was reduced (50-80%) in pre-eclampsia. CGS-21680 (A(2A) agonist) did not alter hENTs expression or activity, but ZM-241385 (A(2A) antagonist) blocked pre-eclampsia effects and increased hENT1-mechated transport in normal pregnancies. Thus, A(2B) adenosine receptors may differentially modulate hENTs in hPMEC, which could be a mechanism attempting to re-establish physiological extracellular adenosine levels in pre-eclampsia. (C) 2008 Elsevier Ltd. All rights reserved.
- ItemHypoxia-reduced nitric oxide synthase activity is partially explained by higher arginase-2 activity and cellular redistribution in human umbilical vein endothelium(W B SAUNDERS CO LTD, 2011) Prieto, C. P.; Krause, B. J.; Quezada, C.; San Martin, R.; Sobrevia, L.; Casanello, P.Hypoxia relates with altered placental vasodilation, and in isolated endothelial cells, it reduces activity of the endothelial nitric oxide synthase (eNOS) and L-arginine transport. It has been reported that arginase-2 expression, an alternative pathway for L-arginine metabolism, is increased in adult endothelial cells exposed to hypoxia as well as in pre-eclamptic placentae. We studied in human umbilical vein endothelial cells (HUVEC) whether hypoxia-reduced NO synthesis results from increased arginase-mediated L-arginine metabolism and changes in subcellular localization of eNOS and arginase-2. In HUVEC exposed (24 h) to 5% (normoxia) or 2% (hypoxia) oxygen, L-arginine transport kinetics, arginase activity (urea assay), and NO synthase (NOS) activity (L-citrulline assay) were determined. Arginase-1, arginase-2 and eNOS expression were determined by RT-PCR and Western blot. Subcellular localization of arginase-2 and eNOS were studied using confocal microscopy and indirect immunofluorescence. Experiments were done in absence or presence of S-(2-boronoethyl)-L-cysteine-HCl (BEC, arginase inhibitor) or N-G-nitro-L-arginine methyl ester (L-NAME). Hypoxia-induced reduction in eNOS activity was associated with a reduction in eNOS phosphorylation at Serine-1177 and increased phosphorylation at Threonine-495. This was paralleled with an induction in arginase-2 expression and activity, and decreased L-arginine transport. In hypoxia the arginase inhibition, restored NO synthesis and L-arginine transport, without changes in the eNOS post-translational modification status. Hypoxia increased arginase-2/eNOS colocalization, and eNOS redistribution to the cell periphery. Altogether these data reinforce the thought that eNOS cell location, post-translational modification and substrate availability are important mechanisms regulating eNOS activity. If these mechanisms occur in pregnancy diseases where feto-placental oxygen levels are reduced remains to be clarified. (C) 2011 Elsevier Ltd. All rights reserved.
- ItemMATERNAL OBESITY IMPAIRS MIGRATION OF FETAL ENDOTHELIUM INVOLVING ENDOPLASMIC RETICULUM STRESS(W B SAUNDERS CO LTD, 2015) Villalobos Labra, R.; Saez, P. J.; Gonzalez, I.; Westermeier, F.; Sobrevia, L.; Casanello, P.; Owen, G. I.; Farias Jofre, M.
- ItemMaternal Obesity Is Associated With Higher Cord Blood Adipokines in Offspring Most Notably in Females.(2021) Jaramillo-Ospina, Á; Castaño-Moreno, E.; Muñoz-Muñoz, E.; Krause, B. J.; Uauy, R.; Casanello, P.; Castro-Rodríguez, José Antonio
- ItemNitric oxide reduces SLC29A1 promoter activity and adenosine transport involving transcription factor complex hCHOP–C/EBPα in human umbilical vein endothelial cells from gestational diabetes(2010) Farías, M.; Puebla, C.; Westermeier, F.; Jo, M. J.; Pastor-Anglada, M.; Casanello, P.; Sobrevia, L.