Browsing by Author "Leiva, Andrea"

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    Aldosterone and renin concentrations were abnormally elevated in a cohort of normotensive pregnant women
    (2022) Pasten, Valentina; Tapia-Castillo, Alejandra; Fardella, Carlos E.; Leiva, Andrea; Carvajal, Cristian A.
    Background During pregnancy, the renin-angiotensin-aldosterone system (RAAS) undergoes major changes to preserve normal blood pressure (BP) and placental blood flow and to ensure a good pregnancy outcome. Abnormal aldosterone-renin metabolism is a risk factor for arterial hypertension and cardiovascular risk, but its association with pathological conditions in pregnancy remains unknown. Moreover, potential biomarkers associated with these pathological conditions should be identified. Aim To study a cohort of normotensive pregnant women according to their serum aldosterone and plasma renin levels and assay their small extracellular vesicles (sEVs) and a specific protein cargo (LCN2, AT1R). Methods A cohort of 54 normotensive pregnant women at term gestation was included. We determined the BP, serum aldosterone, and plasma renin concentrations. In a subgroup, we isolated their plasma sEVs and semiquantitated two EV proteins (AT1R and LCN2). Results We set a normal range of aldosterone and renin based on the interquartile range. We identified 5/54 (9%) pregnant women with elevated aldosterone and low renin levels and 5/54 (9%) other pregnant women with low aldosterone and elevated renin levels. No differences were found in sEV-LCN2 or sEV-AT1R. Conclusion We found that 18% of normotensive pregnant women had either high aldosterone or high renin levels, suggesting a subclinical status similar to primary aldosteronism or hyperreninemia, respectively. Both could evolve to pathological conditions by affecting the maternal vascular and renal physiology and further the BP. sEVs and their specific cargo should be further studied to clarify their role as potential biomarkers of RAAS alterations in pregnant women.
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    Altered Chemokine Receptor Expression in Papillary Thyroid Cancer
    (MARY ANN LIEBERT, INC, 2009) Gonzalez, Hernan E.; Leiva, Andrea; Tobar, Hugo; Boehmwald, Karen; Tapia, Grace; Torres, Javiera; Mosso, Lorena M.; Bueno, Susan M.; Gonzalez, Pablo; Kalergis, Alexis M.; Riedel, Claudia A.
    Background: Papillary thyroid cancer (PTC), the most prevalent type of differentiated thyroid carcinoma, displays a strikingly high frequency of lymph node metastasis (LNM). Recent data suggest that chemokines can play an important role in promoting tumor progression and metastatic migration of tumor cells. Here we have evaluated whether PTC tissues express a different pattern of chemokine receptors and if the expression of these receptors correlates with LNM.
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    Cholesterol uptake and efflux are impaired in human trophoblast cells from pregnancies with maternal supraphysiological hypercholesterolemia
    (2020) Fuenzalida, Barbara; Cantin, Claudette; Kallol, Sampada; Carvajal, Lorena; Pasten, Valentina; Contreras-Duarte, Susana; Albrecht, Christiane; Gutierrez, Jaime; Leiva, Andrea
    Maternal physiological (MPH) or supraphysiological hypercholesterolaemia (MSPH) occurs during pregnancy. Cholesterol trafficking from maternal to foetal circulation requires the uptake of maternal LDL and HDL by syncytiotrophoblast and cholesterol efflux from this multinucleated tissue to ApoA-I and HDL. We aimed to determine the effects of MSPH on placental cholesterol trafficking. Placental tissue and primary human trophoblast (PHT) were isolated from pregnant women with total cholesterol <280 md/dL (MPH, n = 27) or >= 280 md/dL (MSPH, n = 28). The lipid profile in umbilical cord blood from MPH and MSPH neonates was similar. The abundance of LDL receptor (LDLR) and HDL receptor (SR-BI) was comparable between MSPH and MPH placentas. However, LDLR was localized mainly in the syncytiotrophoblast surface and was associated with reduced placental levels of its ligand ApoB. In PHT from MSPH, the uptake of LDL and HDL was lower compared to MPH, without changes in LDLR and reduced levels of SR-BI. Regarding cholesterol efflux, in MSPH placentas, the abundance of cholesterol transporter ABCA1 was increased, while ABCG1 and SR-BI were reduced. In PHT from MSPH, the cholesterol efflux to ApoA-I was increased and to HDL was reduced, along with reduced levels of ABCG1, compared to MPH. Inhibition of SR-BI did not change cholesterol efflux in PHT. The TC content in PHT was comparable in MPH and MSPH cells. However, free cholesterol was increased in MSPH cells. We conclude that MSPH alters the trafficking and content of cholesterol in placental trophoblasts, which could be associated with changes in the placenta-mediated maternal-to-foetal cholesterol trafficking.
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    Functional Link Between Adenosine and Insulin: A Hypothesis for Fetoplacental Vascular Endothelial Dysfunction in Gestational Diabetes
    (BENTHAM SCIENCE PUBL LTD, 2011) Guzman Gutierrez, Enrique; Abarzua, Fernando; Belmar, Cristian; Nien, Jyh K.; Ramirez, Marco A.; Arroyo, Pablo; Salomon, Carlos; Westermeier, Francisco; Puebla, Carlos; Leiva, Andrea; Casanello, Paola; Sobrevia, Luis
    Gestational diabetes mellitus (GDM) is a syndrome compromising the health of the mother and the fetus. Endothelial damage and reduced metabolism of the vasodilator adenosine occur and fetal hyperinsulinemia associated with deficient insulin response and a metabolic rather than mitogenic phenotype is characteristic of this pathology. These phenomena lead to endothelial dysfunction of the fetoplacental unit. Major databases were searched for the relevant literature in the field. Special attention was placed on publications related with diabetes and hormone/metabolic disorders. We aimed to summarize the information regarding insulin sensitivity changes in GDM and the role of adenosine in this phenomenon. Evidence supporting the possibility that fetal endothelial dysfunction involves a functional link between adenosine and insulin signaling in the fetal endothelium from GDM pregnancies is summarized. Since insulin acts via membrane receptors type A (preferentially associated with mitogenic responses) or type B (preferentially associated with metabolic responses), a differential activation of these receptors in this syndrome is proposed.
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    Gestational Diabetes Mellitus Treatment Schemes Modify Maternal Plasma Cholesterol Levels Dependent to Women's Weight: Possible Impact on Feto-Placental Vascular Function
    (2020) Contreras-Duarte, Susana; Carvajal, Lorena; Jesus Garchitorena, Maria; Subiabre, Mario; Fuenzalida, Barbara; Cantin, Claudette; Farias, Marcelo; Leiva, Andrea
    Gestational diabetes mellitus (GDM) associates with fetal endothelial dysfunction (ED), which occurs independently of adequate glycemic control. Scarce information exists about the impact of different GDM therapeutic schemes on maternal dyslipidemia and obesity and their contribution to the development of fetal-ED. The aim of this study was to evaluate the effect of GDM-treatments on lipid levels in nonobese (N) and obese (O) pregnant women and the effect of maternal cholesterol levels in GDM-associated ED in the umbilical vein (UV). O-GDM women treated with diet showed decreased total cholesterol (TC) and low-density lipoproteins (LDL) levels with respect to N-GDM ones. Moreover, O-GDM women treated with diet in addition to insulin showed higher TC and LDL levels than N-GDM women. The maximum relaxation to calcitonin gene-related peptide of the UV rings was lower in the N-GDM group compared to the N one, and increased maternal levels of TC were associated with even lower dilation in the N-GDM group. We conclude that GDM-treatments modulate the TC and LDL levels depending on maternal weight. Additionally, increased TC levels worsen the GDM-associated ED of UV rings. This study suggests that it could be relevant to consider a specific GDM-treatment according to weight in order to prevent fetal-ED, as well as to consider the possible effects of maternal lipids during pregnancy.
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    Gestational Diabetes Reduces Adenosine Transport in Human Placental Microvascular Endothelium, an Effect Reversed by Insulin
    (PUBLIC LIBRARY SCIENCE, 2012) Salomon, Carlos; Westermeier, Francisco; Puebla, Carlos; Arroyo, Pablo; Guzman Gutierrez, Enrique; Pardo, Fabian; Leiva, Andrea; Casanello, Paola; Sobrevia, Luis
    Gestational diabetes mellitus (GDM) courses with increased fetal plasma adenosine concentration and reduced adenosine transport in placental macrovascular endothelium. Since insulin modulates human equilibrative nucleoside transporters (hENTs) expression/activity, we hypothesize that GDM will alter hENT2-mediated transport in human placental microvascular endothelium (hPMEC), and that insulin will restore GDM to a normal phenotype involving insulin receptors A (IR-A) and B (IR-B). GDM effect on hENTs expression and transport activity, and IR-A/IR-B expression and associated cell signalling cascades (p42/44 mitogen-activated protein kinases (p42/44(mapk)) and Akt) role in hPMEC primary cultures was assayed. GDM associates with elevated umbilical whole and vein, but not arteries blood adenosine, and reduced hENTs adenosine transport and expression. IR-A/IR-B mRNA expression and p42/44(mapk)/Akt ratios ('metabolic phenotype') were lower in GDM. Insulin reversed GDM-reduced hENT2 expression/activity, IR-A/IR-B mRNA expression and p42/44(mapk)/Akt ratios to normal pregnancies ('mitogenic phenotype'). It is suggested that insulin effects required IR-A and IR-B expression leading to differential modulation of signalling pathways restoring GDM-metabolic to a normal-mitogenic like phenotype. Insulin could be acting as protecting factor for placental microvascular endothelial dysfunction in GDM.
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    Increased Circulating Levels of PCSK9 and Pro-Atherogenic Lipoprotein Profile in Pregnant Women with Maternal Supraphysiological Hypercholesterolemia
    (2022) Cantin, Claudette; Jesus Garchitorena, Maria; Escalona, Rodrigo; Carvajal, Jorge A.; Illanes, Sebastian E.; Gutierrez, Jaime; Leiva, Andrea
    Maternal physiological hypercholesterolemia (MPH) occurs during pregnancy to assure fetal development. Some pregnant women develop maternal supraphysiological hypercholesterolemia (MSPH) characterized by increased levels of low-density lipoprotein (LDL). We aim to determine if proprotein convertase subtilisin/kexin type 9 (PCSK9) levels (a protein that regulate the availability of LDL receptor in the cells surface), as well as the composition and function of LDL, are modulated in MSPH women. This study included 122 pregnant women. Maternal total cholesterol (TC), LDL, triglycerides and PCSK9 increased from first (T1) to third trimester (T3) in MPH women. At T3, maternal TC, LDL, PCSK9 and placental abundances of PCSK9 were significantly higher in MPSH compared to MPH. Circulating PCSK9 levels were correlated with LDL at T3. In MSPH women, the levels of lipid peroxidation and oxidized LDL were significantly higher compared to MPH. LDL isolated from MSPH women presented significantly higher triglycerides and ApoB but lower levels of ApoAI compared to MPH. The formation of conjugated dienes was earlier in LDL from MSPH and in endothelial cells incubated with these LDLs; the levels of reactive oxygen species were significantly higher compared to LDL from MPH. We conclude that increased maternal PCSK9 would contribute to the maternal elevated levels of pro-atherogenic LDL in MSPH, which could eventually be related to maternal vascular dysfunction.
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    Insulin Restores Gestational Diabetes Mellitus Reduced Adenosine Transport Involving Differential Expression of Insulin Receptor Isoforms in Human Umbilical Vein Endothelium
    (AMER DIABETES ASSOC, 2011) Westermeier, Francisco; Salomon, Carlos; Gonzalez, Marcelo; Puebla, Carlos; Guzman Gutierrez, Enrique; Cifuentes, Fredi; Leiva, Andrea; Casanello, Paola; Sobrevia, Luis
    OBJECTIVE-To determine whether insulin reverses gestational diabetes mellitus (GDM)-reduced expression and activity of human equilibrative nucleoside transporters 1 (hENT1) in human umbilical vein endothelium cells (HUVECs).
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    Insulin-Increased L-Arginine Transport Requires A(2A) Adenosine Receptors Activation in Human Umbilical Vein Endothelium
    (PUBLIC LIBRARY SCIENCE, 2012) Guzman Gutierrez, Enrique; Westermeier, Francisco; Salomon, Carlos; Gonzalez, Marcelo; Pardo, Fabian; Leiva, Andrea; Sobrevia, Luis
    Adenosine causes vasodilation of human placenta vasculature by increasing the transport of arginine via cationic amino acid transporters 1 (hCAT-1). This process involves the activation of A(2A) adenosine receptors (A(2A)AR) in human umbilical vein endothelial cells (HUVECs). Insulin increases hCAT-1 activity and expression in HUVECs, and A(2A)AR stimulation increases insulin sensitivity in subjects with insulin resistance. However, whether A(2A)AR plays a role in insulin-mediated increase in L-arginine transport in HUVECs is unknown. To determine this, we first assayed the kinetics of saturable L-arginine transport (1 minute, 37 degrees C) in the absence or presence of nitrobenzylthioinosine (NBTI, 10 mu mol/L, adenosine transport inhibitor) and/or adenosine receptors agonist/antagonists. We also determined hCAT-1 protein and mRNA expression levels (Western blots and quantitative PCR), and SLC7A1 (for hCAT-1) reporter promoter activity. Insulin and NBTI increased the extracellular adenosine concentration, the maximal velocity for L-arginine transport without altering the apparent K-m for L-arginine transport, hCAT-1 protein and mRNA expression levels, and SLC7A1 transcriptional activity. An A2AAR antagonist ZM-241385 blocked these effects. ZM241385 inhibited SLC7A1 reporter transcriptional activity to the same extent in cells transfected with pGL3-hCAT-1(-1606) or pGL3-hCAT-1(-650) constructs in the presence of NBTI + insulin. However, SLC7A1 reporter activity was increased by NBTI only in cells transfected with pGL3-hCAT-1(-1606), and the ZM-241385 sensitive fraction of the NBTI response was similar in the absence or in the presence of insulin. Thus, insulin modulation of hCAT-1 expression and activity requires functional A(2A)AR in HUVECs, a mechanism that may be applicable to diseases associated with fetal insulin resistance, such as gestational diabetes.
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    Insulin-Stimulated L-Arginine Transport Requires SLC7A1 Gene Expression and Is Associated With Human Umbilical Vein Relaxation
    (WILEY, 2011) Gonzalez, Marcelo; Gallardo, Victoria; Rodriguez, Natalia; Salomon, Carlos; Westermeier, Francisco; Guzman Gutierrez, Enrique; Abarzua, Fernando; Leiva, Andrea; Casanello, Paola; Sobrevia, Luis
    Insulin causes endothelium-derived nitric oxide (NO)-dependent vascular relaxation, and increases L-arginine transport via cationic amino acid transporter 1 (hCAT-1) and endothelialNOsynthase (eNOS) expression and activity in human umbilical vein endothelium (HUVEC). We studied insulin effect on SLC7A1 gene (hCAT-1) expression and hCAT-transport activity role in insulin-modulated human fetal vascular reactivity. HUVEC were used for L-arginine transport and L-[H-3] citrulline formation (NOS activity) assays in absence or presence of N-ethylmaleimide (NEM) or L-lysine (L-arginine transport inhibitors). hCAT-1 protein abundance was estimated by Western blot, mRNA quantification by real time PCR, and SLC7A1 promoter activity by Luciferase activity (-1,606 and -650 bp promoter fragments from ATG). Specific protein 1 (Sp1), and total or phosphorylatedeNOSprotein was determined by Western blot. Sp1 activity (at four sites between -177 and -105 bp from ATG) was assayed by chromatin immunoprecipitation (ChIP) and vascular reactivity in umbilical vein rings. Insulin increased hCATs-L-arginine transport, maximal transport capacity (V-max/K-m), and hCAT-1 expression. NEM and L-lysine blocked L-arginine transport. In addition, it was trans-stimulated (similar to 7.8-fold) by L-lysine in absence of insulin, but unaltered (similar to 1.4-fold) in presence of insulin. Sp1 nuclear protein abundance and binding to DNA, and SLC7A1 promoter activity was increased by insulin. Insulin increasedNOsynthesis and caused endothelium-dependent vessel relaxation and reduced U46619-induced contraction, effects blocked by NEM and L-lysine, and dependent on extracellular L-arginine. We suggest that insulin induces human umbilical vein relaxation by increasing HUVEC L-arginine transport via hCATs (likely hCAT-1) most likely requiring Sp1-activated SLC7A1 expression. J. Cell. Physiol. 226: 2916-2924, 2011. (C) 2011 Wiley-Liss, Inc.
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    Maternal insulin therapy does not restore foetoplacental endothelial dysfunction in gestational diabetes mellitus
    (2017) Subiabre, Mario; Silva, Luis; Villalobos-Labra, Roberto; Toledo, Fernando; Paublo, Mario; Lopez, Marcia A.; Salsoso, Rocio; Pardo, Fabian; Leiva, Andrea; Sobrevia, Luis
    Pregnant women diagnosed with gestational diabetes mellitus subjected to diet (GDMd) that do not reach normal glycaemia are passed to insulin therapy (GDMi). GDMd associates with increased human cationic amino acid transporter 1 (hCAT-1)-mediated transport of L-arginine and nitric oxide synthase (NOS) activity in foetoplacental vasculature, a phenomenon reversed by exogenous insulin. Whether insulin therapy results in reversal of the GDMd effect on the foetoplacental vasculature is unknown. We assayed whether insulin therapy normalizes GDMd-associated foetoplacental endothelial dysfunction. Primary cultures of human umbilical vein endothelial cells (HUVECs) from GDMi pregnancies were used to assay L-arginine transport kinetics, NOS activity, p44/42(mapk) and protein kinase B/Akt activation, and umbilical vein rings reactivity. HUVECs from GDMi or GDMd show increased hCAT-1 expression and maximal transport capacity, NOS activity, and eNOS, and p44/42(mapk), but not Akt activator phosphorylation. Dilation in response to insulin or calcitonin-gene related peptide was impaired in umbilical vein rings from GDMi and GDMd pregnancies. Incubation of HUVECs in vitro with insulin (1 nmol/L) restored hCAT-1 and eNOS expression and activity, and eNOS and p44/42(mapk) activator phosphorylation. Thus, maternal insulin therapy does not seem to reverse GDMd-associated alterations in human foetoplacental vasculature.
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    PDZK1 is required for maintaining hepatic scavenger receptor, class B, type I (SR-BI) steady state levels but not its surface localization or function
    (AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2006) Yesilaltay, Ayce; Kocher, Olivier; Pal, Rinku; Leiva, Andrea; Quinones, Veronica; Rigotti, Attilio; Krieger, Monty
    PDZK1 is a multi-PDZ domain-containing adaptor protein that binds to the C terminus of the high density lipoprotein receptor, scavenger receptor, class B, type I (SR-BI), and controls the posttranscriptional, tissue-specific expression of this lipoprotein receptor. In the absence of PDZK1 (PDZK1(-/-) mice), murine hepatic SR-BI protein levels are very low (< 5% of control). As a consequence, abnormal plasma lipoprotein metabolism (similar to 1.5-1.7-fold increased total plasma cholesterol carried in both normal size and abnormally large high density lipoprotein particles) resembles, but is not as severely defective as, that in SR-BI(-/-) mice. Here we show that the total plasma cholesterol levels and size distribution of lipoproteins are virtually identical in SR-BI(-/-) and SR-BI(-/-)/ PDZK1(-/-) mice, indicating that most, if not all of the effects of PDZK1 on lipoprotein metabolism are likely because of the effects of PDZK1 on SR-BI. Hepatic overexpression of wild-type SR-BI in PDZK1(-/-) mice restored near or greater than normal levels of cell surface-expressed, functional SR-BI protein levels in the livers of SR-BI(-/-)/ PDZK1(-/-) mice and consequently restored apparently normal lipoprotein metabolism in the absence of PDZK1. Thus, PDZK1 is important for maintaining adequate steady state levels of SR-BI in the liver but is not essential for cell surface expression or function of hepatic SR-BI.
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    Potential Role of Sodium-Proton Exchangers in the Low Concentration Arsenic Trioxide-Increased Intracellular pH and Cell Proliferation
    (PUBLIC LIBRARY SCIENCE, 2012) Aravena, Carmen; Beltran, Ana R.; Cornejo, Marcelo; Torres, Viviana; Diaz, Emilce S.; Guzman Gutierrez, Enrique; Pardo, Fabian; Leiva, Andrea; Sobrevia, Luis; Ramirez, Marco A.
    Arsenic main inorganic compound is arsenic trioxide (ATO) presented in solution mainly as arsenite. ATO increases intracellular pH (pHi), cell proliferation and tumor growth. Sodium-proton exchangers (NHEs) modulate the pHi, with NHE1 playing significant roles. Whether ATO-increased cell proliferation results from altered NHEs expression and activity is unknown. We hypothesize that ATO increases cell proliferation by altering pHi due to increased NHEs-like transport activity. Madin-Darby canine kidney (MDCK) cells grown in 5 mmol/L D-glucose-containing DMEM were exposed to ATO (0.05, 0.5 or 5 mu mol/L, 0-48 hours) in the absence or presence of 5-N, N-hexamethylene amiloride (HMA, 5-100 mu mol/L, NHEs inhibitor), PD-98059 (30 mu mol/L, MAPK1/2 inhibitor), Go6976 (10 mu mol/L, PKC alpha, beta I and mu inhibitor), or Schering 28080 (10 mu mol/L, H+/K(+)ATPase inhibitor) plus concanamycin (0.1 mu mol/L, V type ATPases inhibitor). Incorporation of [H-3]thymidine was used to estimate cell proliferation, and counting cells with a hemocytometer to determine the cell number. The pHi was measured by fluorometry in 2,7-bicarboxyethyl-5,6-carboxyfluorescein loaded cells. The Na+-dependent HMA-sensitive NHEs-like mediated proton transport kinetics, NHE1 protein abundance in the total, cytoplasm and plasma membrane protein fractions, and phosphorylated and total p42/44 mitogen-activated protein kinases (p42/44(mapk)) were also determined. Lowest ATO (0.05 mu mol/L, similar to 0.01 ppm) used in this study increased cell proliferation, pHi, NHEs-like transport and plasma membrane NHE1 protein abundance, effects blocked by HMA, PD-98059 or Go6976. Cell-buffering capacity did not change by ATO. The results show that a low ATO concentration increases MDCK cells proliferation by NHEs (probably NHE1)-like transport dependent-increased pHi requiring p42/44(mapk) and PKC alpha, beta I and/or mu activity. This finding could be crucial in diseases where uncontrolled cell growth occurs, such as tumor growth, and in circumstances where ATO, likely arsenite, is available at the drinking-water at these levels. Citation: Aravena C, Beltran AR, Cornejo M, Torres V, Diaz ES, et al. (2012) Potential Role of Sodium-Proton Exchangers in the Low Concentration Arsenic Trioxide-Increased Intracellular pH and Cell Proliferation. PLoS ONE 7(12): e51451. doi:10.1371/journal.pone.0051451
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    Small extracellular vesicles from pregnant women with maternal supraphysiological hypercholesterolemia impair endothelial cell function in vitro
    (2023) Contreras-Duarte, Susana; Escalona-Rivano, Rodrigo; Cantin, Claudette; Valdivia, Pascuala; Zapata, David; Carvajal, Lorena; Brito, Roberto; Cerda, Alvaro; Illanes, Sebastian; Gutierrez, Jaime; Leiva, Andrea
    Maternal physiological hypercholesterolemia MPH, maternal total cholesterol (TC) levels at term of pregnancy <280 mg/dL) occurs to assure fetal development. Maternal supraphysiological hypercholesterolemia (MSPH, TC levels >280 mg/dL) is a pathological condition associated with maternal, placental, and fetal endothelial dysfunction and early neonatal atherosclerosis development. Small extracellular vesicles (sEVs) are delivered to the extracellular space by different cells, where they modulate cell functions by transporting active signaling molecules, including proteins and miRNA.Aim: To determine whether sEVs from MSPH women could alter the function of endothelial cells (angiogenesis, endothelial activation and nitric oxide synthesis capacity).Methods: This study included 24 Chilean women (12 MPH and 12 MSPH). sEVs were isolated from maternal plasma and characterized by sEV markers (CD9, Alix and HSP70), nanoparticle tracking analysis, transmission electron microscopy, and protein and cholesterol content. The endothelial cell line HMEC-1 was used to determine the uptake of labeled sEVs and the effects of sEVs on cell viability, endothelial tube formation, endothelial cell activation, and endothelial nitric oxide expression and function.Results: In MSPH women, the plasma concentration of sEVs was increased compared to that in MPH women. MSPH-sEVs were highly taken up by HMEC-1 cells and reduced angiogenic capacity and the expression and activity of eNOS without changing cell viability or endothelial activation compared to MPH-sEVs. Conclusion: sEVs from MSPH women impair angiogenesis and nitric oxide synthesis in endothelial cells, which could contribute to MSPH-associated endothelial dysfunction.
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    The autophagy process and oxidized LDL independently modulate the invasion and differentiation of extravillous trophoblastic cells to an endothelial-like phenotype in normoxia
    (2024) Carvajal, Lorena; Escalona, Rodrigo; Rivera, Patricia; Aguilera-Olguin, Macarena; Hernandez-Caceres, Maria Paz; Gutierrez, Jaime; Morselli, Eugenia; Leiva, Andrea
    Introduction: The mechanisms leading to proper placentation are not fully understood. Extravillous trophoblasts (EVTs) are crucial for placentation through invasion and vascular remodeling, which, when impaired, promote a poor placentation. How autophagy could regulate EVTs function and the study of regulators of these processes, such as oxidized low-density lipoproteins (ox-LDL), could contribute to better understand events associated with pregnancy complications related to abnormal placental development, such as preeclampsia (PE). Aim: To investigate the role of autophagy and oxidized LDL (ox-LDL) in invasion and endothelial-like phenotype acquisition of a model of EVTs, as well as to determine the levels of autophagy flux markers in control and PE placentas. Methods: Invasion and endothelial-like phenotype acquisition assays were performed in a cell line model of first trimester EVTs: HTR-8/SVneo cultured in normoxia (oxygen concentration of 20 %), in the absence or the presence of the autophagy inhibitor bafilomycin or/and ox-LDL. Markers of autophagic flux were evaluated in human term placentas. Results: Autophagy is essential for EVTs to acquire an endothelial-like phenotype but does not affect invasion. Conversely, ox-LDL decreases invasion and reticular structures formation, independent of autophagy. At pregnancy term, the levels of the autophagy markers LC3 and p62 are deregulated in the trophoblast cells of PE placentas. Conclusion: Autophagy is necessary for proper endothelial-like phenotype acquisition in HTR-8/SVneo cultured in normoxia, and ox-LDL impairs this process as well as the invasion of EVTs by a mechanism independent of autophagy. Changes in autophagy and/or in the concentration of ox-LDL could affect placental vascular remodeling.
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    The polarized localization of lipoprotein receptors and cholesterol transporters in the syncytiotrophoblast of the placenta is reproducible in a monolayer of primary human trophoblasts
    (2021) Fuenzalida, Barbara; Kallol, Sampada; Luthi, Michael; Albrecht, Christiane; Leiva, Andrea
    Introduction: The uptake of low- and high-density lipoproteins (LDL and HDL) through the LDL receptor (LDLR) and the scavenger receptor class B type I (SR-BI) mediates maternal to fetal cholesterol transfer in syncytiotrophoblast (STB) cells. STB cells deliver cholesterol via cholesterol efflux through the ATP-binding cassette transporters A1 (ABCA1, to ApoA-I), G1 (ABCG1, to HDL), and SR-BI (to HDL). In the human placenta, these proteins are localized in the apical (LDLR, SR-BI, ABCA1) and basal (SR-BI, ABCA1, ABCG1) membrane of STB cells. However, whether these proteins in polarized primary culture models of STB show a similar localization to those in the human placenta is currently unknown.