Browsing by Author "Sobrevía Luarte, Luis Alberto"

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    5, '-ectonucleotidase mediates multiple-drug resistance in glioblastoma multiforme cells
    (2013) Quezada, Claudia; Garrido, Wallys; Oyarzún, Carlos; Fernández, Katia; Segura Segura, Rodrigo; Melo, Rómulo; Casanello Toledo, Paola Cecilia; Sobrevía Luarte, Luis Alberto; San Martin, Rody
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    Cross Talk between Adipose Tissue and Placenta in Obese and Gestational Diabetes Mellitus Pregnancies via Exosomes
    (2017) Jayabalan, N.; Nair, S.; Nuzhat, Z.; Rice, G.; Zúñiga, F.; Sobrevía Luarte, Luis Alberto; Leiva Mendoza, Andrea Alejandra; Sanhueza, C.; Gutiérrez, J.; Lappas, M.; Freeman, D.; Salomon, C.
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    Foetoplacental epigenetic changes associated with maternal metabolic dysfunction
    (2018) Kerr, Bredford; Leiva Mendoza, Andrea Alejandra; Farías Jofré, Marcelo Enrique; Contreras Duarte, Susana de las Mercedes; Toledo, Fernando; Stolzenbach, Francisca; Silva, Luis; Sobrevía Luarte, Luis Alberto
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    Gestational Diabetes and the Adenosine/L-Arginine/Nitric Oxide (ALANO) Pathway in Human Umbilical Vein Endothelium
    (2006) San Martín, R.; Sobrevía Luarte, Luis Alberto
    Altered endothelial cell function is a key factor associated with vascular disorders and is critical in the fetal growth and development. Pregnancies affected by diseases such as gestational diabetes are associated with human umbilical vein endothelial dysfunction, a finding that has been associated with a high incidence of vascular complications during the adult life. Limited information is available addressing cellular mechanisms associated with altered human umbilical vein endothelial function in gestational diabetes. One of the key signalling pathways associated with altered vascular physiology is the synthesis of the vasodilator nitric oxide (NO) from the cationic amino acid L-arginine by the endothelium (i.e. the endothelial L-arginine/NO pathway). The activity of this signalling pathway is modulated by D-glucose, adenosine, insulin, and ATP, among other molecules, and is upregulated (transcriptional, post-transcriptional and post-translational levels) in gestational diabetes. This review focuses on the cellular and molecular mechanisms involved with elevated adenosine levels in fetal umbilical vein blood and the endothelial L-arginine/NO pathway activity in gestational diabetes. We suggest that a lower capacity of adenosine transport by the fetal endothelium in gestational diabetes leads to extracellular accumulation of this nucleoside and its higher bio-availability activates endothelial P1 type purinoceptors. A functional association between A2a purinoceptor subtype signalling and the activity of the L-arginine transport mediated by human cationic amino acid transporters and endothelial NO synthase activity (i.e. ‘ALANO pathway’) is proposed, revealing in part the mechanisms that account for human umbilical vein endothelial cell dysfunction programmed through the development of the fetus in gestational diabetes.
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    Hypoxia increases equilibrative nucleoside transporter 2 activity by a transcriptional independent mechanism in human umbilical vein endothelium
    (2006) Torres, A; San Martin, R; Farías Jofré, Marcelo Enrique; Sobrevía Luarte, Luis Alberto; Casanello Toledo, Paola Cecilia
    Low oxygen tension (hypoxia) reduces adenosine transport in several types of mammalian cells. Adenosine transport is mediated by human equilibrative nucleoside transporter 1 (hENT1) and hENT2 in human umbilical vein endothelium (HUVEC), a fetal cell type that grows under 5% O2 (ie. normoxia for this cell type). We studied whether hypoxia alters hENT2 expression and activity in HUVEC. Methods: Cells were cultured (0-24 h) in 5% or 2% O2 (hypoxia), and [3H]adenosine uptake (125 and 500 μM, 4 μCi/ml, 20 s, 37°C) was measured in absence or presence of 100 nM nitrobenzylthioinosine (NBMPR, hENT1 inhibitor). hENT2 mRNA was quantified by real time RT-PCR, and protein abundance was determined by Western blot. SLC29A2 (for hENT2) promoter activity was measured following transfection (electroporation, 320 V, 30 ms) with pGL3 basic plasmid (firefly/renilla luciferase reporter gene) carrying -1477 bp and -587 bp of the promoter sequence. Results: Hypoxia reduced hENT2 mRNA expression (~55%), and promoter activity (~50%), but did not alter hENT2 protein abundance. Adenosine uptake via hENT2 was increased (2-fold) in hypoxia. Conclusions: Adenosine uptake via hENT2 may be modulated by post-translational mechanisms in hypoxia in HUVEC. Supported by FONDECYT 1030781/1030607/7050030. A Torres holds a School of Medicine research fellowship, and M Farías holds a CONICYT-PhD fellowship.
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    Insulin requires A2B adenosine receptors to modulate the L-arginine/nitric oxide signalling in the human fetoplacental vascular endothelium from late-onset preeclampsia
    (2021) Salsoso Rodríguez, M. Rocío; Mate, A.; Toledo Tapia, Fernando; Vázquez, C. M.; Sobrevía Luarte, Luis Alberto
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    Insulin requires normal expression and signaling of insulin receptor A to reverse gestational diabetes-reduced adenosine transport in human umbilical vein endothelium
    (2015) Westermeier, Francisco; Salomón, Carlos; Farías Jofré, Marcelo Enrique; Arroyo, Pablo; Fuenzalida Saavedra, Bárbara; Sáez, Tamara; Salsoso Rodríguez, M. Rocío; Sanhueza, Carlos; Guzmán-Gutierrez, Enrique; Pardo, Fabián; Leiva Mendoza, Andrea Alejandra; Sobrevía Luarte, Luis Alberto
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    Insulin/adenosine axis linked signalling
    (2017) Silva Lagos, Luis Alfredo; Subiabre Morales, Mario Enrique; Araos, J.; Saez, T.; Salsoso Rodríguez, M. Rocío; Pardo, F.; Leiva Mendoza, Andrea Alejandra; San Martin, R.; Toledo, F.; Sobrevía Luarte, Luis Alberto
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    Is there a role for exosomes in foetoplacental endothelial dysfunction in gestational diabetes mellitus?
    (2018) Sáez, Tamara; De Vos, Paul; Sobrevía Luarte, Luis Alberto; Faas, Marijke M.
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    Oxidative stress: Normal pregnancy versus preeclampsia
    (2020) Chiarello, D. I.; Abad, C.; Rojas, D.; Toledo Tapia, Fernando; Vazquez, C. M.; Mate, A.; Sobrevía Luarte, Luis Alberto; Marin, R.
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    Pre-pregnancy maternal obesity associates with endoplasmic reticulum stress in human umbilical vein endothelium
    (2018) Villalobos Labra, Roberto Esteban; Saez, P.; Subiabre Morales, Mario Enrique; Silva, L.; Toledo, F.; Westermeier, F.; Pardo, F.; Farías Jofré, Marcelo Enrique; Sobrevía Luarte, Luis Alberto
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    Preeclampsia associates with RECK-dependent decrease in human trophoblasts migration and invasion
    (2017) Gutiérrez, Jaime; Aedo, Alejandro; Mora, Jacob; Maldonado, Jorge; Salsoso Rodríguez, M. Rocío; Toledo, Fernando; Farías Jofré, Marcelo Enrique; Pardo, Fabián; Leiva Mendoza, Andrea Alejandra; Sobrevía Luarte, Luis Alberto
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    Reduced Insulin Response in Human Umbilical Vein Endothelial Cells from Pregnancies with Maternal Obesity Is Associated with Activation of PERK Branch of Endoplasmic Reticulum Stress Pathway
    (2013) Farías Jofré, Marcelo Enrique; Westermeier Lafuente, Francisco David; Kusanovic Pivcevic, Juan Pedro; Poblete Lizana, José Andrés; Mardones S., Francisco; Sobrevía Luarte, Luis Alberto
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    Role of arginase-2 and eNOS in the differential vascular reactivity and hypoxia-induced endothelial response in umbilical arteries and veins
    (2012) Krause Leyton, Bernardo; Muñoz Urrutia, Ernesto Alejandro; Sobrevía Luarte, Luis Alberto
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    Sodium/proton exchanger isoform 1 regulates intracellular pH and cell proliferation in human ovarian cancer
    (2017) Sanhueza, Carlos; Araos, Joaquín; Naranjo, Luciano; Toledo, Fernando; Beltrán, Ana R.; Ramirez, Marco A.; Gutiérrez, Jaime; Pardo, Fabián; Leiva Mendoza, Andrea Alejandra; Sobrevía Luarte, Luis Alberto
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    TGF-beta1 inhibits expression and activity of hENT1 in a nitric oxide-dependent manner in human umbilical vein endothelium
    (2009) Vega Pizarro, José Luis Eduardo; Puebla Aracena, Carlos Alberto; Vásquez, Rodrigo; Farías Jofré, Marcelo Enrique; Alarcón, Julio; Pastor-Anglada, Marçal; Krause Leyton, Bernardo; Casanello Toledo, Paola Cecilia; Sobrevía Luarte, Luis Alberto
    Aims: We studied whether transforming growth factor β1 (TGF-β1) modulates human equilibrative nucleoside transporters 1 (hENT1) expression and activity in human umbilical vein endothelial cells (HUVECs). hENT1-mediated adenosine transport and expression are reduced in gestational diabetes and hyperglycaemia, conditions associated with increased synthesis and release of nitric oxide (NO) and TGF-β1 in this cell type. TGF-β1 increases NO synthesis via activation of TGF-β receptor type II (TβRII), and NO inhibits hENT1 expression and activity in HUVECs. Methods and results: HUVECs (passage 2) were used for experiments. Total and hENT1-mediated adenosine transport was measured in the absence or presence of TGF-β1, NG-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor), S-nitroso-N-acetyl-L,D-penicillamine (SNAP, NO donor), and/or KT-5823 (protein kinase G inhibitor) in control cells and cells expressing a truncated form of TGF-β1 receptor type II (TTβRII). Western blot and real-time PCR were used to determine hENT1 protein abundance and mRNA expression. SLC29A1 gene promoter and specific protein 1 (Sp1) transcription factor activity was assayed. Vascular reactivity was assayed in endothelium-intact or -denuded umbilical vein rings. TGF-β1 reduced hENT1-mediated adenosine transport, hENT1 protein abundance, hENT1 mRNA expression, and SLC29A1 gene promoter activity, but increased Sp1 binding to DNA. TGF-β1 effect was blocked by L-NAME and KT-5823 and mimicked by SNAP in control cells. However, TGF-β1 was ineffective in cells expressing TTβRII or a mutated Sp1 consensus sequence. Vasodilatation in response to TGF-β1 and S-(4-nitrobenzyl)-6-thio-inosine (an ENT inhibitor) was endothelium-dependent and blocked by KT-5823 and ZM-241385. Conclusion: hENT1 is down-regulated by activation of TβRII by TGF-β1 in HUVECs, a phenomenon where NO and Sp1 play key roles. These findings comprise physiological mechanisms that could be important in diseases where TGF-β1 plasma level is increased as in gestational diabetic mothers or patients with diabetes mellitus.
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    The activity of IKCa and BKCa channels contributes to insulin-mediated NO synthesis and vascular tone regulation in human umbilical vein
    (2020) Rojas, S.; Basualto, E.; Valdivia, L.; Vallejos, N.; Ceballos, K.; Peña, E.; Rivas, C.; Nualart, F.; Guzmán Gutiérrez, E.; Sobrevía Luarte, Luis Alberto; Escudero, C.; Toledo, F.; Cid, M.; González, M.
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    The transcriptional repression of equilibrative nucleoside transporter 1 by D-glucose rfsponses to transcription factor Sp1 and ZBP-89 in human foetal endothelium
    (2008) Puebla Aracena, Carlos Alberto; Farías Jofré, Marcelo Enrique; Vega Pizarro, José Luis Eduardo; Pastor-Anglada, M.; Casanello Toledo, Paola Cecilia; Sobrevía Luarte, Luis Alberto
    Objectives: Adenosine is a vasodilator in most vascular beds, an effect depending on its extracellular concentration. Uptake of this nucleoside in human umbilical vein endothelial cells (HUVEC) is mainly mediated by human equilibrative nucleoside transporters 1 (hENT1). hENT1 expression and transport activity are reduced in HUVEC exposed to high D-glucose. Since specific mechanisms for these effects of D-glucose are unknown, we examined the role of Sp1 and BP-89 transcription factors on SLC29A1 (for hENT1) promoter activity in response to D-glucose. Methods: HUVEC from normal pregnancies were isolated and exposed (24 h) to 5 mM (normal) or 25 mM (high) D-glucose. Sp1 protein levels were evaluated by western blot in nuclear fractions. Reporter activity of plasmid constructs containing a wild type promoter region of SLC29A1 (-1114 bp to ATG, pGL3-hENT1-1114), or mutations (by PCR) for Sp1 (-815/-801 bp, pGL3-hENT1-1114mutSp1) or ZBP-89 (-992/-969 bp, pGL3-hENT1-1114mutZBP) or both (-1114 bp, pGL3-hENT1-1114mutSp1/ZBP) binding sites were assayed in cells over-expressing Sp1 (using pCGN-Sp1 vector). Results: Nuclear Sp1 abundance was increased, but pGL3-hENT1-1114 transcriptional activity was reduced by high D-glucose. Sp1 over-expression reduced pGL3-hENT1-1114 transcriptional activity in normal or high D-glucose. The effect of high D-glucose or Sp1 over-expression was absent in pGL3-hENT1-1114mutSp1, pGL3-hENT1-1114mutZBP and pGL3-hENT1-1114mutSp1/ZBP cells. Conclusion: A repression of the SLC29A1 promoter activity by Sp1 and ZBP-89 could explain the reduced hENT1 expression and activity exhibited by HUVEC in high extracellular D-glucose. FONDECYT 1070865/1080534/7070249 (Chile), AECI A/5484/06 (Spain). C Puebla andJL Vega hold CONICYT fellowships. M Farías holds CONICYT and PUC-School of Medicine PhD fellowships.
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    Transcriptional repression of equilibrative nucleoside transporter 1 by D-glucose involves nitric oxide and Sp1 in human foetal endothelium
    (2007) Puebla Aracena, Carlos Alberto; Farías Jofré, Marcelo Enrique; Vecchiola Cárdenas, Andrea Paola; Casanello Toledo, Paola Cecilia; Sobrevía Luarte, Luis Alberto
    Adenosine uptake via the human equilibrative nucleoside transporters 1 (hENT1) is reduced in human umbilical vein endothelial cells (HUVEC) exposed to high D-glucose. Since specific mechanisms by which D-glucose reduces hENT1 expression and activity in these cells are unknown, we examined the role of nitric oxide (NO) and Sp1 as modulators of SLC29A1 (for hENT1) promoter activity in response to D-glucose. HUVEC from normal pregnancies were isolated and exposed (24 h) to 5 mM (normal) or 25 mM (high) D-glucose in absence or presence of NG-nitro-L-arginine methyl ester (LNAME, 100 mM). Sp1 protein levels were evaluated by western blot in nuclear fractions. Reporter activity of plasmid constructs containing a promoter region of SLC29A1 (-1114 bp to ATG, pGL3-hENT1-1114), Sp1 overexpression experiments (co-transfection with the expression vector pCGN-Sp1) and Sp1 binding to this region (chromatin immunoprecipitation) was assayed. pGL3-hENT1-1114 transcriptional activity was reduced by high Dglucose and in cells overexpressing Sp1. Nuclear Sp1 abundance and specific binding to its consensus sequence in SLC29A1 promoter (-815 to -801 bp) were higher in high D-glucose (1.9- and 1.7-fold, respectively) compared with normal D-glucose. All these effects were blocked by L-NAME. Thus, a NO-dependent Sp1 repression on SLC29A1 promoter could explain the reduced hENT1 expression and activity exhibited by HUVEC in high extracellular D-glucose. FONDECYT 1070865, VRAID2007-PUC (Chile). AECI A/5484/06 (Spain). C. Puebla holds a PUC-VRAID PhD fellowship. M. Farías hold CONICYT and PUC-School of Medicine PhD fellowships