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BACKGROUND: NEK10, a serine/threonine/tyrosine kinase belonging to the NEK (NIMA-related kinases) family, has been associated with diverse cellular processes. However, no specific target pathways have been identified. Our previous work knocking down NEK10 in HeLa cells suggested a functional association with mitochondria, as we observed altered mitochondrial morphology, mitochondrial oxygen consumption, mtDNA integrity, and reactive oxygen species levels. METHODS: To better understand this association, we studied human HAP1 cells fully knockout for NEK10 and confirmed that NEK10 has an important role in mitochondrial homeostasis. We performed the study of mitochondrial respiration, mitochondrial morphology, mitochondrial mass, and mtDNA analysis. Additionally, we showed proteome and phosphoproteome data of crude mitochondrial fraction of Parental and NEK10 KO cells using liquid chromatography-mass spectrometry (LC-MS/MS). RESULTS: In the absence of NEK10 several mitochondrial functions were disturbed. Moreover, proteome and phosphoproteome analyses of mitochondrial fractions showed that NEK10 alters the threonine phosphorylation status of several mitochondrial/endoplasmic reticulum components, including HSP60, NDUFB4, and TOM20. These changes impacted the steady-state levels of a larger group of proteins, preferentially involving respiratory complexes and autophagy pathways. CONCLUSION: We concluded that NEK10 plays a key role in mitochondrial function, possibly by modulating the phosphorylation status of mitochondrial proteins.
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While mechanisms controlling uncoupling protein-1 (UCP1) in thermogenic adipocytes play a pivotal role in non-shivering thermogenesis, it remains unclear whether F1Fo-ATP synthase function is also regulated in brown adipose tissue (BAT). Here, we show that inhibitory factor 1 (IF1, encoded by Atp5if1), an inhibitor of ATP synthase hydrolytic activity, is a critical negative regulator of brown adipocyte energy metabolism. In vivo, IF1 levels are diminished in BAT of cold-adapted mice compared to controls. Additionally, the capacity of ATP synthase to generate mitochondrial membrane potential (MMP) through ATP hydrolysis (the so-called "reverse mode" of ATP synthase) is increased in brown fat. In cultured brown adipocytes, IF1 overexpression results in an inability of mitochondria to sustain the MMP upon adrenergic stimulation, leading to a quiescent-like phenotype in brown adipocytes. In mice, adeno-associated virus-mediated IF1 overexpression in BAT suppresses adrenergic-stimulated thermogenesis and decreases mitochondrial respiration in BAT. Taken together, our work identifies downregulation of IF1 upon cold as a critical event for the facilitation of the reverse mode of ATP synthase as well as to enable energetic adaptation of BAT to effectively support non-shivering thermogenesis.
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Proteína Inhibidora ATPasa , Tejido Adiposo Pardo , Frío , ATPasas de Translocación de Protón Mitocondriales , Termogénesis , Animales , Termogénesis/genética , Ratones , Tejido Adiposo Pardo/metabolismo , ATPasas de Translocación de Protón Mitocondriales/metabolismo , ATPasas de Translocación de Protón Mitocondriales/genética , Hidrólisis , Mitocondrias/metabolismo , Ratones Endogámicos C57BL , Masculino , Adipocitos Marrones/metabolismo , Potencial de la Membrana Mitocondrial , Metabolismo EnergéticoRESUMEN
Overall health relies on features of skeletal muscle that generally decline with age, partly due to mechanisms associated with mitochondrial redox imbalance and bioenergetic dysfunction. Previously, aged mice genetically devoid of the mitochondrial NAD(P)+ transhydrogenase (NNT, encoded by the nicotinamide nucleotide transhydrogenase gene), an enzyme involved in mitochondrial NADPH supply, were shown to exhibit deficits in locomotor behavior. Here, by using young, middle-aged, and older NNT-deficient (Nnt-/-) mice and age-matched controls (Nnt+/+), we aimed to investigate how muscle bioenergetic function and motor performance are affected by NNT expression and aging. Mice were subjected to the wire-hang test to assess locomotor performance, while mitochondrial bioenergetics was evaluated in fiber bundles from the soleus, vastus lateralis and plantaris muscles. An age-related decrease in the average wire-hang score was observed in middle-aged and older Nnt-/- mice compared to age-matched controls. Although respiratory rates in the soleus, vastus lateralis and plantaris muscles did not significantly differ between the genotypes in young mice, the rates of oxygen consumption did decrease in the soleus and vastus lateralis muscles of middle-aged and older Nnt-/- mice. Notably, the soleus, which exhibited the highest NNT expression level, was the muscle most affected by aging, and NNT loss. Additionally, histology of the soleus fibers revealed increased numbers of centralized nuclei in older Nnt-/- mice, indicating abnormal morphology. In summary, our findings suggest that NNT expression deficiency causes locomotor impairments and muscle dysfunction during aging in mice.
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Envejecimiento , Metabolismo Energético , Mitocondrias Musculares , Músculo Esquelético , Animales , Envejecimiento/metabolismo , Envejecimiento/fisiología , Ratones , Músculo Esquelético/metabolismo , Mitocondrias Musculares/metabolismo , Masculino , NADP Transhidrogenasa AB-Específica/metabolismo , NADP Transhidrogenasa AB-Específica/genética , Consumo de Oxígeno/fisiología , Ratones Noqueados , Ratones Endogámicos C57BL , Proteínas MitocondrialesRESUMEN
In this study, a novel genus is proposed, Scaptona, with a novel species, Scaptona ramosa, isolated from nests of stingless bees (Scaptotrigona sp.). The taxonomic novelty was determined by the phylogenetic analysis of DNA sequences from the internal transcribed spacer regions, small subunit rRNA (18S rRNA), large subunit rRNA (28S rRNA) and the RNA polymerase II second-largest subunit gene (RPB2) and paired with our morphological studies. Based on this single species, Scaptona is characterized by greyish green to dark grey colonies, densely and profusely branched conidiophores and single-celled, variously shaped hyaline conidia. Scaptona ramosa constitutes a distinct, well-supported lineage within Cephalothecaceae and can be clearly distinguished from other genera both by DNA sequence analysis and morphological traits. The holotype of S. ramosa is URM 95352. The ex-type strain has been deposited in the Micoteca URM culture collection as URM 8721T and URM 8722. The MycoBank accession number is MB 849456 for the genus and MB 849456 for the species.
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Ácidos Grasos , Animales , Abejas , Filogenia , Análisis de Secuencia de ADN , ARN Ribosómico 16S/genética , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , Composición de Base , Ácidos Grasos/química , ARN Ribosómico 18SRESUMEN
OBJECTIVE: To describe current treatment practices of preterm infants with early hypoxemic respiratory failure (HRF) and pulmonary hypertension (PH) and their association with patient outcomes. STUDY DESIGN: We developed a prospective, observational, multicenter clinical registry of preterm newborns <34 weeks' gestation with HRF and PH, based on either clinical or echocardiographic evidence during the first 72 hours of life, from 28 neonatal intensive care units in the US from 2017 through 2022. The primary end point was mortality among those who did or did not receive PH-targeted treatment, and the secondary end points included comparisons of major morbidities. Variables were compared using t tests, Wilcoxon rank-sum tests, Fisher exact tests, and χ² tests. RESULTS: We analyzed the results of 224 preterm infants enrolled in the registry. Of which, 84% (188/224) received PH-targeted treatment, most commonly inhaled nitric oxide (iNO). Early mortality in this cohort was high, as 33% (71/224) of this sample died in the first month of life, and 77% of survivors (105/137) developed bronchopulmonary dysplasia. Infants who received PH-targeted treatment had higher oxygenation indices at the time of enrollment (28.16 [IQR: 13.94, 42.5] vs 15.46 [IQR: 11.94, 26.15]; P = .0064). Patient outcomes did not differ between those who did or did not receive PH-targeted therapy. CONCLUSIONS: Early-onset HRF with PH in preterm infants is associated with a high early mortality and a high risk of developing bronchopulmonary dysplasia. iNO is commonly used to treat early-onset PH in preterm infants with HRF. In comparison with untreated infants with lower oxygenation indices, iNO treatment in severe PH may prevent poorer outcomes.
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Displasia Broncopulmonar , Hipertensión Pulmonar , Insuficiencia Respiratoria , Lactante , Recién Nacido , Humanos , Recien Nacido Prematuro , Displasia Broncopulmonar/terapia , Displasia Broncopulmonar/tratamiento farmacológico , Hipertensión Pulmonar/tratamiento farmacológico , Estudios Prospectivos , Insuficiencia Respiratoria/terapia , Óxido Nítrico , Administración por InhalaciónRESUMEN
Understanding the role of astrocytes in the development of the nervous system and neurodegenerative disorders implies a necessary knowledge of the oxidative metabolism of proliferating astrocytes. The electron flux through mitochondrial respiratory complexes and oxidative phosphorylation may impact the growth and viability of these astrocytes. Here, we aimed at assessing to which extent mitochondrial oxidative metabolism is required for astrocyte survival and proliferation. Primary astrocytes from the neonatal mouse cortex were cultured in a physiologically relevant medium with the addition of piericidin A or oligomycin at concentrations that fully inhibit complex I-linked respiration and ATP synthase, respectively. The presence of these mitochondrial inhibitors for up to 6 days in a culture medium elicited only minor effects on astrocyte growth. Moreover, neither the morphology nor the proportion of glial fibrillary acidic protein-positive astrocytes in culture was affected by piericidin A or oligomycin. Metabolic characterization of the astrocytes showed a relevant glycolytic metabolism under basal conditions, despite functional oxidative phosphorylation and large spare respiratory capacity. Our data suggest that astrocytes in primary culture can sustainably proliferate when their energy metabolism relies only on aerobic glycolysis since their growth and survival do not require electron flux through respiratory complex I or oxidative phosphorylation.
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Complejo I de Transporte de Electrón , Fosforilación Oxidativa , Ratones , Animales , Complejo I de Transporte de Electrón/metabolismo , Astrocitos/metabolismo , Mitocondrias/metabolismo , Oligomicinas/farmacologíaRESUMEN
Determination of oxygen consumption is one of the most valuable methodologies to evaluate mitochondrial (dys)function. Previous studies demonstrated that a widely used protocol, consisting of adding the ATP synthase inhibitor oligomycin before mitochondrial respiratory uncoupling by sequential addition of a protonophore (e.g., carbonyl cyanide 3-chlorophenyl hydrazone [CCCP]), may lead to underestimation of maximal oxygen consumption rate (OCRmax) and spare respiratory capacity (SRC) parameters in highly glycolytic tumor cell lines. In this dataset, we report the effects of the glycolytic inhibitors 2-deoxy-D-glucose, iodoacetic acid, and lonidamine on overcoming the underestimation of OCRmax and SRC in oligomycin-treated cells. We propose a protocol in which 2-deoxy-D-glucose is added after oligomycin and just before the sequential addition of CCCP to avoid underestimation of OCRmax and SRC parameters in A549, C2C12, and T98G cells. The oxygen consumption rates were determined in intact suspended cell lines using a high-resolution oxygraph device. The data can be used in several fields of research that require characterization of mitochondrial respiratory parameters in intact cells.
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The interaction between supraphysiological cytosolic Ca2+ levels and mitochondrial redox imbalance mediates the mitochondrial permeability transition (MPT). The MPT is involved in cell death, diseases and aging. This study compared the liver mitochondrial Ca2+ retention capacity and oxygen consumption in the long-lived red-footed tortoise (Chelonoidis carbonaria) with those in the rat as a reference standard. Mitochondrial Ca2+ retention capacity, a quantitative measure of MPT sensitivity, was remarkably higher in tortoises than in rats. This difference was minimized in the presence of the MPT inhibitors ADP and cyclosporine A. However, the Ca2+ retention capacities of tortoise and rat liver mitochondria were similar when both MPT inhibitors were present simultaneously. NADH-linked phosphorylating respiration rates of tortoise liver mitochondria represented only 30% of the maximal electron transport system capacity, indicating a limitation imposed by the phosphorylation system. These results suggested underlying differences in putative MPT structural components [e.g. ATP synthase, adenine nucleotide translocase (ANT) and cyclophilin D] between tortoises and rats. Indeed, in tortoise mitochondria, titrations of inhibitors of the oxidative phosphorylation components revealed a higher limitation of ANT. Furthermore, cyclophilin D activity was approximately 70% lower in tortoises than in rats. Investigation of critical properties of mitochondrial redox control that affect MPT demonstrated that tortoise and rat liver mitochondria exhibited similar rates of H2O2 release and glutathione redox status. Overall, our findings suggest that constraints imposed by ANT and cyclophilin D, putative components or regulators of the MPT pore, are associated with the enhanced resistance to Ca2+-induced MPT in tortoises.
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Tortugas , Animales , Calcio/metabolismo , Peptidil-Prolil Isomerasa F , Peróxido de Hidrógeno , Mitocondrias Hepáticas/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Necrosis por Permeabilidad de la Transmembrana Mitocondrial , Permeabilidad , Ratas , Tortugas/metabolismoRESUMEN
NAD(P)+ transhydrogenase (NNT) is located in the inner mitochondrial membrane and catalyzes a reversible hydride transfer between NAD(H) and NADP(H) that is coupled to proton translocation between the intermembrane space and mitochondrial matrix. NNT activity has an essential role in maintaining the NADPH supply for antioxidant defense and biosynthetic pathways. In the present report, we evaluated the effects of chemical compounds used as inhibitors of NNT over the last five decades, namely, 4-chloro-7-nitrobenzofurazan (NBD-Cl), N,N'-dicyclohexylcarbodiimide (DCC), palmitoyl-CoA, palmitoyl-l-carnitine, and rhein, on NNT activity and mitochondrial respiratory function. Concentrations of these compounds that partially inhibited the forward and reverse NNT reactions in detergent-solubilized mouse liver mitochondria significantly impaired mitochondrial respiratory function, as estimated by ADP-stimulated and nonphosphorylating respiration. Among the tested compounds, NBD-Cl showed the best relationship between NNT inhibition and low impact on respiratory function. Despite this, NBD-Cl concentrations that partially inhibited NNT activity impaired mitochondrial respiratory function and significantly decreased the viability of cultured Nnt-/- mouse astrocytes. We conclude that even though the tested compounds indeed presented inhibitory effects on NNT activity, at effective concentrations, they cause important undesirable effects on mitochondrial respiratory function and cell viability.
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Inhibidores Enzimáticos/farmacología , Mitocondrias Hepáticas/enzimología , NADP Transhidrogenasa AB-Específica/antagonistas & inhibidores , NADP Transhidrogenasa AB-Específica/metabolismo , Consumo de Oxígeno/efectos de los fármacos , Animales , Inhibidores Enzimáticos/química , Femenino , Ratones , Ratones Noqueados , Mitocondrias Hepáticas/genética , Proteínas Mitocondriales/antagonistas & inhibidores , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , NADP Transhidrogenasa AB-Específica/genética , Consumo de Oxígeno/genéticaRESUMEN
OBJECTIVES: To utilize a large multicenter neonatal cohort to describe survival and clinical outcomes of very low birth weight (VLBW) or preterm infants with ectopia cordis. STUDY DESIGN: Data were prospectively collected on 2â211â262 infants (born 2000-2017) from 845 US centers. Both VLBW (401-1500 g or 22-29 weeks of gestation) and non-VLBW (>1500 g and >29 weeks) infants had diagnoses or anatomic descriptors consistent with ectopia cordis and/or pentalogy of Cantrell. The primary outcome was neonatal survival, defined as hospital discharge or initial length of stay of ≥12 months. RESULTS: In total, 180 infants had ectopia cordis, 135 (76%) with findings of pentalogy of Cantrell. VLBW infants comprised 52% of the population. VLBW mortality was 96% with 79% dying within 12 hours, compared with 59% and 36%, respectively, for non-VLBW. One-third of VLBW infants received life support compared with 65% of non-VLBW. Surgery was reported for 34% of VLBW and 68% of non-VLBW infants. Congenital heart disease was reported in 8% of VLBW and 36% of non-VLBW, with conotruncal abnormalities most common. Survival exceeded 50% for infants >2500 g and >37 weeks of gestation. CONCLUSIONS: Survival of VLBW infants with ectopia cordis was poor and substantially worse compared with non-VLBW, with notable discrepancies in resuscitative efforts and surgical interventions. Although gestational age and weight strongly influence current survival, more detailed information regarding the severity of cardiac and noncardiac abnormalities is required to fully determine prognosis and inform counseling.
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Ectopía Cordis/mortalidad , Tiempo de Internación/estadística & datos numéricos , Estudios de Casos y Controles , Preescolar , Edad Gestacional , Humanos , Lactante , Recién Nacido , Recién Nacido de muy Bajo Peso , Estudios Prospectivos , Estados Unidos/epidemiologíaRESUMEN
This study sought to elucidate how oligomycin, an ATP synthase blocker, leads to underestimation of maximal oxygen consumption rate (maxOCR) and spare respiratory capacity (SRC) in tumor cells. T98G and U-87MG glioma cells were titrated with the protonophore CCCP to induce maxOCR. The presence of oligomycin (0.3-3.0 µg/mL) led to underestimation of maxOCR and a consequent decrease in SRC values of between 25% and 40% in medium containing 5.5 or 11 mM glucose. The inhibitory effect of oligomycin on CCCP-induced maxOCR did not occur when glutamine was the metabolic substrate or when the glycolytic inhibitor 2-deoxyglucose was present. ATP levels were reduced and ADP/ATP ratios increased in cells treated with CCCP, but these changes were minimized when oligomycin was used to inhibit reverse activity of ATP synthase. Exposing digitonin-permeabilized cells to exogenous ATP, but not ADP, resulted in partial inhibition of CCCP-induced maxOCR. We conclude that underestimation of maxOCR and SRC in tumor cells when ATP synthase is inhibited is associated with high glycolytic activity and that the glycolytic ATP yield may have an inhibitory effect on the metabolism of respiratory substrates and cytochrome c oxidase activity. Under CCCP-induced maxOCR, oligomycin preserves intracellular ATP by inhibiting ATP synthase reverse activity.
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Adenosina Trifosfato/metabolismo , Transporte de Electrón/fisiología , Glucólisis/fisiología , Mitocondrias/metabolismo , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Neoplasias/metabolismo , Línea Celular Tumoral , Desoxiglucosa/metabolismo , Humanos , Oligomicinas/metabolismo , Consumo de Oxígeno/fisiologíaRESUMEN
INTRODUCTION: Tumor necrosis factor-alpha (TNF-α) exerts a critical role in inflammatory events through two distinct receptors, TNFR1 and TNFR2. Platelets have been recognized as important inflammatory cells, but little is known about the effects of TNF-α on the platelet activity. OBJECTIVES: In the present study we have studied the role of TNF-α on ADP-induced platelet aggregation and its downstream signaling (c-Src and fibrinogen receptor phosphorylation, cytosolic Ca2+ mobilization, cAMP and cGMP levels and cell viability). METHODS AND RESULTS: Washed rat platelets were incubated with TNF-α (1-3000â¯pg/ml) for different time-periods (5-60â¯min) before the addition of ADP (5⯵M) to induce platelet aggregation. TNF-α concentration- and time-dependently inhibits ADP-induced aggregation, which was significantly prevented by incubation with the non-selective TNF-α receptor antagonist R7050. TNF-α (300â¯pg/ml, 30â¯min) decreases thrombin-induced elevation of cytosolic Ca++ levels by 2.2- fold compared to untreated platelets. TNF-α decreases the cAMP levels, while significantly increases the intracellular cyclic cGMP levels. However, the pre-incubation of platelets with the guanylyl cyclase inhibitor ODQ, despite decreasing the cGMP levels, does not modify the inhibitory effect of TNF-α on ADP-induced platelet aggregation. Additionally, western blotting analysis showed that TNF-α significantly reduced (Tyr 416)-c-Src and (Tyr773)-ß3 subunit of αIIbß3 integrin phosphorylation. TNF-α does not affect the platelet viability in any condition tested. CONCLUSION: Therefore, our results show that TNF-α negatively modulates ADP-induced aggregation via TNFR1/TNFR2 receptors by reducing cytosolic Ca++ levels and by inhibiting c-Src and fibrinogen receptor activation, which take place through cAMP- and cGMP-independent mechanisms.
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Plaquetas/metabolismo , Calcio/metabolismo , Integrina beta3/metabolismo , Agregación Plaquetaria , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Glicoproteína IIb de Membrana Plaquetaria/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Plaquetas/citología , GMP Cíclico/metabolismo , Citosol/metabolismo , Masculino , Fosforilación , Ratas WistarRESUMEN
Among mitochondrial NADP-reducing enzymes, nicotinamide nucleotide transhydrogenase (NNT) establishes an elevated matrix NADPH/NADP+ by catalyzing the reduction of NADP+ at the expense of NADH oxidation coupled to inward proton translocation across the inner mitochondrial membrane. Here, we characterize NNT activity and mitochondrial redox balance in the brain using a congenic mouse model carrying the mutated Nnt gene from the C57BL/6J strain. The absence of NNT activity resulted in lower total NADPH sources activity in the brain mitochondria of young mice, an effect that was partially compensated in aged mice. Nonsynaptic mitochondria showed higher NNT activity than synaptic mitochondria. In the absence of NNT, an increased release of H2 O2 from mitochondria was observed when the metabolism of respiratory substrates occurred with restricted flux through relevant mitochondrial NADPH sources or when respiratory complex I was inhibited. In accordance, mitochondria from Nnt-/- brains were unable to sustain NADP in its reduced state when energized in the absence of carbon substrates, an effect aggravated after H2 O2 bolus metabolism. These data indicate that the lack of NNT in brain mitochondria impairs peroxide detoxification, but peroxide detoxification can be partially counterbalanced by concurrent NADPH sources depending on substrate availability. Notably, only brain mitochondria from Nnt-/- mice chronically fed a high-fat diet exhibited lower activity of the redox-sensitive aconitase, suggesting that brain mitochondrial redox balance requires NNT under the metabolic stress of a high-fat diet. Overall, the role of NNT in the brain mitochondria redox balance especially comes into play under mitochondrial respiratory defects or high-fat diet.
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Química Encefálica/fisiología , Dieta Alta en Grasa , Metabolismo Energético/fisiología , Mitocondrias/metabolismo , NADP Transhidrogenasa AB-Específica/metabolismo , Envejecimiento , Animales , Química Encefálica/efectos de los fármacos , Complejo I de Transporte de Electrón , Metabolismo Energético/efectos de los fármacos , Peróxido de Hidrógeno/metabolismo , Potencial de la Membrana Mitocondrial , Ratones Congénicos , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/efectos de los fármacos , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , NADP/metabolismo , NADP Transhidrogenasa AB-Específica/genética , Oxidación-Reducción , Consumo de Oxígeno/genética , Consumo de Oxígeno/fisiología , Sinaptosomas/metabolismoRESUMEN
The mechanisms by which a high fat diet (HFD) promotes non-alcoholic fatty liver disease (NAFLD) appear to involve liver mitochondrial dysfunctions and redox imbalance. We hypothesized that a HFD would increase mitochondrial reliance on NAD(P)-transhydrogenase (NNT) as the source of NADPH for antioxidant systems that counteract NAFLD development. Therefore, we studied HFD-induced liver mitochondrial dysfunctions and NAFLD in C57Unib.B6 congenic mice with (Nnt+/+) or without (Nnt-/-) NNT activity; the spontaneously mutated allele (Nnt-/-) was inherited from the C57BL/6J mouse substrain. After 20 weeks on a HFD, Nnt-/- mice exhibited a higher prevalence of steatohepatitis and content of liver triglycerides compared to Nnt+/+ mice on an identical diet. Under a HFD, the aggravated NAFLD phenotype in the Nnt-/- mice was accompanied by an increased H2O2 release rate from mitochondria, decreased aconitase activity (a redox-sensitive mitochondrial enzyme) and higher susceptibility to Ca2+-induced mitochondrial permeability transition. In addition, HFD led to the phosphorylation (inhibition) of pyruvate dehydrogenase (PDH) and markedly reduced the ability of liver mitochondria to remove peroxide in Nnt-/- mice. Bypass or pharmacological reactivation of PDH by dichloroacetate restored the peroxide removal capability of mitochondria from Nnt-/- mice on a HFD. Noteworthy, compared to mice that were chow-fed, the HFD did not impair peroxide removal nor elicit redox imbalance in mitochondria from Nnt+/+ mice. Therefore, HFD interacted with Nnt mutation to generate PDH inhibition and further suppression of peroxide removal. We conclude that NNT plays a critical role in counteracting mitochondrial redox imbalance, PDH inhibition and advancement of NAFLD in mice fed a HFD. The present study provide seminal experimental evidence that redox imbalance in liver mitochondria potentiates the progression from simple steatosis to steatohepatitis following a HFD.
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Peróxido de Hidrógeno/metabolismo , Mitocondrias Hepáticas/enzimología , NADP Transhidrogenasa AB-Específica/genética , Enfermedad del Hígado Graso no Alcohólico/etiología , Estrés Oxidativo , Complejo Piruvato Deshidrogenasa/metabolismo , Aconitato Hidratasa/metabolismo , Animales , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias Hepáticas/metabolismo , Proteínas Mitocondriales/genética , Mutación , Enfermedad del Hígado Graso no Alcohólico/enzimología , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Fosforilación , Procesamiento Proteico-Postraduccional , Triglicéridos/metabolismoRESUMEN
OBJECTIVE: To quantify outcomes and analyze factors predictive of morbidity and mortality in infants with gastroschisis. STUDY DESIGN: Clinical data regarding neonates with gastroschisis born between 2009 and 2014 were prospectively collected at 175 North American centers. Multivariate regression was used to assess risk factors for mortality and length of stay (LOS). RESULTS: Gastroschisis was diagnosed in 4420 neonates with median birth weight 2410 g (IQR 2105-2747). Survival (discharge home or alive in hospital at 1 year) was 97.8% with a 37 day median LOS (IQR 27-59). Sepsis, defined by positive blood or cerebrospinal fluid culture, was the only significant independent predictor of mortality (P = .04). Significant independent determinants of LOS and the percentage of neonates affected were as follows: bowel resection (9.8%, P < .0001), sepsis (8.6%, P < .0001), presence of other congenital anomalies (7.6%, including 5.8% with intestinal atresias, P < .0001), necrotizing enterocolitis (4.5%, P < .0001), and small for gestational age (37.3%, P = .0006). Abdominal surgery in addition to gastroschisis repair occurred in 22.3%, with 6.4% receiving gastrostomy or jejunostomy tubes and 6.3% requiring ostomy creation. At discharge, 57.0% were less than the 10th percentile weight for age. The mode of delivery (52.4% cesarean delivery) was not associated with any differences in outcome. CONCLUSIONS: Although neonates with gastroschisis have excellent overall survival they remain at risk for death from sepsis, prolonged hospitalization, multiple abdominal operations, and malnutrition at discharge. Outcomes appear unaffected by the use of cesarean delivery. Further opportunities for quality improvement include sepsis prevention and enhanced nutritional support.
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Gastrosquisis/epidemiología , Gastrosquisis/cirugía , Estudios de Cohortes , Anomalías Congénitas/epidemiología , Procedimientos Quirúrgicos del Sistema Digestivo/estadística & datos numéricos , Enterocolitis Necrotizante/epidemiología , Femenino , Gastrostomía/estadística & datos numéricos , Humanos , Trastornos de la Nutrición del Lactante/epidemiología , Recién Nacido , Recién Nacido Pequeño para la Edad Gestacional , Atresia Intestinal/epidemiología , Atresia Intestinal/cirugía , Yeyunostomía/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Masculino , América del Norte/epidemiología , Factores de Riesgo , Sepsis/mortalidadRESUMEN
High-grade gliomas are aggressive and intensely glycolytic tumors. In the present study, we evaluated the mitochondrial respiratory function of glioma cells (T98G and U-87MG) and fresh human glioblastoma (GBM) tissue. To this end, measurements of oxygen consumption rate (OCR) were performed under various experimental conditions. The OCR of T98G and U-87MG cells was well coupled to ADP phosphorylation based on the ratio of ATP produced per oxygen consumed of ~2.5. In agreement, the basal OCR of GBM tissue was also partially associated with ADP phosphorylation. The basal respiration of intact T98G and U-87MG cells was not limited by the supply of endogenous substrates, as indicated by the increased OCR in response to a protonophore. These cells also displayed a high affinity for oxygen, as evidenced by the values of the partial pressure of oxygen when respiration is half maximal (p 50). In permeabilized glioma cells, ADP-stimulated OCR was only approximately 50% of that obtained in the presence of protonophore, revealing a significant limitation in oxidative phosphorylation (OXPHOS) relative to the activity of the electron transport system (ETS). This characteristic was maintained when the cells were grown under low glucose conditions. Flux control coefficient analyses demonstrated that the impaired OXPHOS was associated with the function of both mitochondrial ATP synthase and the adenine nucleotide translocator, but not the phosphate carrier. Altogether, these data indicate that the availability and metabolism of respiratory substrates and mitochondrial ETS are preserved in T98G and U-87MG glioma cells even though these cells possess a relatively restrained OXPHOS capability.
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Adenosina Difosfato/metabolismo , Glioma/metabolismo , Glucólisis/fisiología , Mitocondrias/metabolismo , Consumo de Oxígeno/fisiología , Adenosina Trifosfato/metabolismo , Animales , Línea Celular Tumoral , Glioma/patología , Glioma/cirugía , Glucosa/metabolismo , Humanos , Ácido Láctico/metabolismo , Masculino , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Estrés Oxidativo/fisiología , Fosforilación , Prosencéfalo/metabolismo , Ratas WistarRESUMEN
Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels. Graphical Abstract á .
Asunto(s)
Encéfalo/fisiología , Neurotransmisores/análisis , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Animales , Química Encefálica , Ratas , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
The maximal capacity of the mitochondrial electron transport system (ETS) in intact cells is frequently estimated by promoting protonophore-induced maximal oxygen consumption preceded by inhibition of oxidative phosphorylation by oligomycin. In the present study, human glioma (T98G and U-87MG) and prostate cancer (PC-3) cells were titrated with different concentrations of the protonophore CCCP to induce maximal oxygen consumption rate (OCR) within respirometers in a conventional growth medium. The results demonstrate that the presence of oligomycin or its A-isomer leads to underestimation of maximal ETS capacity. In the presence of oligomycin, the spare respiratory capacity (SRC), i.e., the difference between the maximal and basal cellular OCR, was underestimated by 25 to 45%. The inhibitory effect of oligomycin on SRC was more pronounced in T98G cells and was observed in both suspended and attached cells. Underestimation of SRC also occurred when oxidative phosphorylation was fully inhibited by the ATP synthase inhibitor citreoviridin. Further experiments indicated that oligomycin cannot be replaced by the adenine nucleotide translocase inhibitors bongkrekic acid or carboxyatractyloside because, although these compounds have effects in permeabilized cells, they do not inhibit oxidative phosphorylation in intact cells. We replaced CCCP by FCCP, another potent protonophore and similar results were observed. Lower maximal OCR and SRC values were obtained with the weaker protonophore 2,4-dinitrophenol, and these parameters were not affected by the presence of oligomycin. In permeabilized cells or isolated brain mitochondria incubated with respiratory substrates, only a minor inhibitory effect of oligomycin on CCCP-induced maximal OCR was observed. We conclude that unless a previously validated protocol is employed, maximal ETS capacity in intact cells should be estimated without oligomycin. The inhibitory effect of an ATP synthase blocker on potent protonophore-induced maximal OCR may be associated with impaired metabolism of mitochondrial respiratory substrates.