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Figueroa-García MDC, Espinosa-García MT, Martinez-Montes F, Palomar-Morales M, Mejía-Zepeda R. Even a Chronic Mild Hyperglycemia Affects Membrane Fluidity and Lipoperoxidation in Placental Mitochondria in Wistar Rats. PLoS One 2015; 10:e0143778. [PMID: 26630275 PMCID: PMC4667935 DOI: 10.1371/journal.pone.0143778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/09/2015] [Indexed: 11/19/2022] Open
Abstract
It is known the deleterious effects of diabetes on embryos, but the effects of diabetes on placenta and its mitochondria are still not well known. In this work we generated a mild hyperglycemia model in female wistar rats by intraperitoneal injection of streptozotocin in 48 hours-old rats. The sexual maturity onset of the female rats was delayed around 6–7 weeks and at 16 weeks-old they were mated, and sacrificed at day 19th of pregnancy. In placental total tissue and isolated mitochondria, the fatty acids composition was analyzed by gas chromatography, and lipoperoxidation was measured by thiobarbituric acid reactive substances. Membrane fluidity in mitochondria was measured with the excimer forming probe dipyrenylpropane and mitochondrial function was measured with a Clark-type electrode. The results show that even a chronic mild hyperglycemia increases lipoperoxidation and decreases mitochondrial function in placenta. Simultaneously, placental fatty acids metabolism in total tissue is modified but in a different way than in placental mitochondria. Whereas the chronic mild hyperglycemia induced a decrease in unsaturated to saturated fatty acids ratio (U/S) in placental total tissue, the ratio increased in placental mitochondria. The measurements of membrane fluidity showed that fluidity of placenta mitochondrial membranes increased with hyperglycemia, showing consistency with the fatty acids composition through the U/S index. The thermotropic characteristics of mitochondrial membranes were changed, showing lower transition temperature and activation energies. All of these data together demonstrate that even a chronic mild hyperglycemia during pregnancy of early reproductive Wistar rats, generates an increment of lipoperoxidation, an increase of placental mitochondrial membrane fluidity apparently derived from changes in fatty acids composition and consequently, mitochondrial malfunction.
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Affiliation(s)
| | | | | | - Martín Palomar-Morales
- Unidad de Morfología y Función, Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla, State of Mexico, Mexico
| | - Ricardo Mejía-Zepeda
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla, State of Mexico, Mexico
- * E-mail:
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García-Pérez C, Pardo JP, Martínez F. Ca(2+) modulates respiratory and steroidogenic activities of human term placental mitochondria. Arch Biochem Biophys 2002; 405:104-111. [PMID: 12176063 DOI: 10.1016/s0003-9861(02)00274-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We investigated the effects of calcium on the oxidative metabolism and steroidogenic activity of human term placental mitochondria. Submicromolar Ca(2+) concentrations stimulated state 3 oxygen consumption with 2-oxoglutarate and isocitrate and activated the 2-oxoglutarate and the NAD-isocitrate dehydrogenases by diminishing their Michaelis-Menten constants. Ca(2+) inhibited NADP-isocitrate dehydrogenase (NADP-ICDH) and the synthesis of progesterone. The NADP-ICDH maximal velocity was threefold higher than that of NAD-ICDH and had a threefold lower K(m) for isocitrate than NAD-ICDH. Isocitrate but not malate or 2-oxoglutarate supported progesterone synthesis. Calcium inhibition of progesterone synthesis was observed with isocitrate but not with malate or 2-oxoglutarate. Tight regulation of NADP-isocitrate dehydrogenase by calcium ions suggests that this enzyme plays an important role in placental mitochondrial metabolism.
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Affiliation(s)
- Cecilia García-Pérez
- Departamento de Bioqui;mica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, DF 04510, México, Mexico
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Martínez F, Uribe A, Espinosa-García MT, Flores-Herrera O, García-Pérez C, Milán R. Calcium modulates the ATP and ADP hydrolysis in human placental mitochondria. Int J Biochem Cell Biol 2002; 34:992-1003. [PMID: 12007637 DOI: 10.1016/s1357-2725(02)00020-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study evaluated the effect of Ca2+ on the extramitochondrial hydrolysis of ATP and ADP by the extramitochondrial ATPase in isolated mitochondria and submitochondrial particles (SMPs) from human term placenta. The effect of different oxidizable substrates on the hydrolysis of ATP and ADP in the presence of sucrose or K+ was evaluated. Ca2+ increased phosphate release from ATP and ADP, but this stimulation showed different behavior depending on the oxidizable substrate present in the incubation media. Ca2+ stimulated the hydrolysis of ATP and ADP in the presence of sucrose. However, Ca2+ did not stimulate the hydrolysis of ADP in the medium containing K+. Ca2+ showed inhibition depending on the respiratory substrate. This study suggests that the energetic state of mitochondria controls the extramitochondrial ATPase activity, which is modulated by Ca2+ and respiratory substrates.
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Affiliation(s)
- Federico Martínez
- Departamento de Bioquimica, Facultad de Medicina, UNAM Apdo., Postal 70-159, 04510, Mexico City, Mexico.
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Martínez F, Uribe A, Milán R, Teresa Espinosa-García M, Gracía-Pérez C, Flores-Herrera O. Differential effects of magnesium on the hydrolysis of ADP and ATP in human term placenta. Effect of substrates and potassium. Int J Biochem Cell Biol 2002; 34:1004-16. [PMID: 12007638 DOI: 10.1016/s1357-2725(02)00021-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This study evaluates the effect of Mg2+ on the extramitochondrial hydrolysis of ATP and ADP by human term placental mitochondria (HPM) and submitochondrial particle (SMP). Extramitochondrial ATPase and ADPase activities were evaluated in the presence or absence of K+, and different oxidizable substrates. Mg2+ increased both ATP and ADP hydrolysis according to the experimental conditions, and this stimulation was related to the mitochondrial intactness. The ADPase activity in intact mitochondria is 100-fold higher in presence of K+, succinate and 1mM Mg2+ while this activity is only increased by two-fold on the SMP when compared to the sample without Mg2+. It is clearly demonstrated that up-regulation of these enzyme activities occur in intact mitochondria and not on the enzyme itself. The results suggest that the regulation of ATP and ADP hydrolysis is complex, and Mg2+ plays an important role in the modulation of the extramitochondrial ATPase and ADPase activities in HPM
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Affiliation(s)
- Federico Martínez
- Departamento de Bioquímica, Facultad de Medicina, UNAM Apdo, Postal 70-159, Mexico City, Mexico.
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Flores-Herrera O, Uribe A, Pardo JP, Rendón JL, Martínez F. A novel ATP-diphosphohydrolase from human term placental mitochondria. Placenta 1999; 20:475-84. [PMID: 10419813 DOI: 10.1053/plac.1999.0401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This report describes an ATP-diphosphohydrolase activity associated with the inner membrane of human term placental mitochondria. An enriched fraction containing 30 per cent of the total protein and 80 per cent of the total ATP-diphosphohydrolase activity was obtained from submitochondrial particles. ATP-diphosphohydrolase activity was characterized in this fraction. The enzyme had a pH optimum of 8 and catalysed the hydrolysis of triphospho- and diphosphonucleosides other than ATP or ADP. Pyrophosphate was also hydrolysed, but AMP or other monoester phosphates were not. The activity of ATP-diphosphohydrolase was dependent on Mg(2 + ), Ca(2 + )or Mn(2 + )and the enzyme substrate was the cation-nucleotide complex. An excess of free cation produced inhibition.ATP-diphosphohydrolase activity was stimulated at micromolar concentrations of calcium or magnesium in the presence of La-PPi. Negative cooperativity kinetics was observed with all substrates tested. The V(max)ranged from 150 to 300nmol of Pi released/mg/min. The [S](0.5)for nucleotides was 1-10m m and 182m m for PPi. The enzyme was inhibited by orthovanadate, but not by l -phenylalanine, oligomycin, sodium azide, P(1),P(5)-di(adenosine-5')pentaphosphate or sodium fluoride.The experimental evidence showing absence of inhibition by sodium azide and sodium fluoride, hydrolysis of pyrophosphate but not of monoester phosphates, and negative cooperativity suggested that this enzyme was a novel ATP-diphosphohydrolase.
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Affiliation(s)
- O Flores-Herrera
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, México, D. F., 04510, México
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Martínez F, Meaney A, Espinosa-García MT, Pardo JP, Uribe A, Flores-Herrera O. Characterization of the F1F0-ATPase and the tightly-bound ATPase activities in submitochondrial particles from human term placenta. Placenta 1996; 17:345-50. [PMID: 8829218 DOI: 10.1016/s0143-4004(96)90059-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In a previous study we demonstrated the existence of a tightly-bound ATPase in the human placental mitochondria (Martínez et al., 1993). The current study characterizes the ATP hydrolysis produced by the F1F0-ATPase and the tightly-bound ATPase in submitochondrial particles from the human term placenta. Both enzymes were not differentiated by pH. Inhibitors were necessary to distinguish the activity of each enzyme. The kinetic of the total ATP hydrolysis fitted into a model of two enzymes. During the characterization, it was observed that the tightly-bound ATPase activity was partially inhibited by vanadate and Mg2+, whereas the F1F0-ATPase was totally inhibited by Mg2+. Different nucleotides were hydrolyzed by the tightly-bound ATPase; the F1F0-ATPase hydrolyzed exclusively ATP. Glucose-6-phosphate, p-nitrophenylphosphate, or pyrophosphate were not hydrolyzed by the F1F0-ATPase, although some hydrolysis was observed with the tightly-bound ATPase. It is concluded that the tightly-bound ATPase activity corresponded to a 5'-nucelotidase, and that the human placental mitochondria could participate in the metabolism of nucleotides.
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Affiliation(s)
- F Martínez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, México D.F
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Martínez F, Pardo JP, Flores-Herrera O, Espinosa-García MT. The effect of osmolarity on human placental mitochondria function. Int J Biochem Cell Biol 1995; 27:795-803. [PMID: 7584614 DOI: 10.1016/1357-2725(95)00050-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human placental explants survive large changes in osmolarity, but the mechanism for this property is unknown. The goal of this work was to examine the effect of osmolarity on human placental mitochondria. Mitochondria from human term placenta were isolated by differential centrifugation, and incubated in the presence of different concentrations of sucrose or KCl, to modify the osmolarity of the media. Rat liver mitochondria were used as control. The parameters studied were: respiration rate, adenine nucleotide hydrolysis, calcium transport, membrane potential, and mitochondrial morphology. Stimulation of the mitochondrial respiration rate and an increase in Ca2+ transport was observed in the presence of K+. With sucrose, Ca2+ transport showed a complex kinetic behavior, whereas the respiratory control was slightly diminished. Although the ATPase activity was enhanced in the absence of a respiratory substrate, no change in ATP hydrolysis due to osmolarity was observed. ADP hydrolysis was inhibited by a high K+ concentration, but not by sucrose. The membrane potential was not modified by osmolarity, even in the absence of sucrose or K+ in the medium. Mitochondria isolated with KCl showed aggregation, whereas dispersed mitochondria were observed with sucrose. This study showed that sucrose-induced changes in osmolarity, does not modify metabolic and transport properties of human placental mitochondria, whereas KCl-induced osmolarity changes does affect these functions.
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Affiliation(s)
- F Martínez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, México City
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Martínez F, Espinosa-García T, Flores-Herrera O, Pardo JP. Respiratory control induced by ATP in human term placental mitochondria. Placenta 1993; 14:321-31. [PMID: 8367413 DOI: 10.1016/s0143-4004(05)80430-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Oxygen uptake in human placental mitochondria was stimulated by ATP addition. ATP-induced respiration was supported by malate, alpha-keto glutarate, and succinate, and inhibited by oligomycin and carboxytractyloside. This phenomenon was not caused by contamination with unspecific phosphatases or alkaline phosphatase, since NaF, L-phenyl alanine, or P1, P5-di-(adenosine-5') pentaphosphate failed to inhibit oxygen uptake induced by ATP. The stimulation of respiration was caused by an ATPase activity tightly bound to mitochondria, which yields ADP that is responsible for the oxygen uptake. The stimulation was not an uncoupling effect because ATP addition produced a transition between state 3 and 4 of respiration, indicating that ATP was not released from mitochondria.
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Affiliation(s)
- F Martínez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, D.F
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Martínez F, Moncada R, Barcenas FJ, Espinosa-García T. Subcellular localization and properties of adenosine diphosphatase in human placenta. Placenta 1992; 13:463-73. [PMID: 1470606 DOI: 10.1016/0143-4004(92)90052-u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It was found that mitochondria from human placenta exhibited an ADPase activity with the following characteristics. The enzyme responsible for this activity was associated with the inner mitochondrial membrane. It was not released by treatment of the submitochondrial particles with solutions of high ionic strength. Maximal ADP hydrolysis was reached at pH 8. Specific inhibitors for alkaline phosphatase (L-phenylalanine), myokinase (P1,P5-di(adenosine-5')pentaphosphate), or 5'-nucleotidase (concanavalin A) did not decrease ADP hydrolysis. ATP synthesis from ADP by myokinase was about 13 nmol/mg/min, whereas ADP hydrolysis reached values around 500 to 550 nmol/mg/min, indicating that a myokinase-H+ATPase combination could not account for the observed rates of ADP hydrolysis. The activity was stimulated by Mg2+, but high concentrations of this cation produced inhibition. High ADP concentrations did not inhibit ADPase activity. Kinetic measurements of the activity in the submitochondrial particles showed that the true substrate was ADP-Mg. The kinetic studies showed V(app) values of 476 and 270 nmol/mg/min, and Kmapp values of 416 and 8.7 microM.
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Affiliation(s)
- F Martínez
- Departamento de Bioquimica, Facultad de Medicina, Universidad Nacional Autonoma de México, México, D.F
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