RESUMEN
BACKGROUND: Red oak pollen is an important cause of allergic respiratory disease and it is widely distributed in North America and central Europe. To date, however, red oak pollen allergens have not been identified. Here, we describe the allergenic protein profile from red oak pollen. METHODS: Total proteins were extracted from red oak pollen using a modified phenolic extraction method, and, subsequently, proteins were separated by two-dimensional gel electrophoresis (2DE) for both total protein stain (Coomassie Blue) and immunoblotting. A pool of 8 sera from red oak sensitive patients was used to analyze blotted proteins. Protein spots were analyzed by Mass Spectrometry. RESULTS: Electrophoretic pattern of total soluble proteins showed higher intensity bands in the regions of 26-40 and 47-52 kDa. Two dimensional immunoblots using pool sera from patients revealed four allergenic proteins spots with molecular masses in the range from 50 to 55 kDa. Mass spectrometry analysis identified 8 proteins including Enolase 1 and Enolase 1 chloroplastic, Xylose isomerase (X1 isoform), mitochondrial Aldehyde dehydrogenase, UTP-Glusose-1-phosphate uridylyltransferase, Betaxylosidase/alpha-l-arabinofuranosidase and alpha- and beta subunits of ATP synthase. CONCLUSIONS: This study has identified for first time 8 IgE binding proteins from red oak pollen. These findings will pave the way towards the development of new diagnostic and therapeutic modalities for red oak allergy.
RESUMEN
Acanthamoeba spp. are free-living amoebae with a worldwide distribution. These amoebae can cause granulomatous amoebic encephalitis and amoebic keratitis in humans. Proteases are considered virulence factors in pathogenic Acanthamoeba. The objective of this study was to evaluate the behavior of Acanthamoeba mauritaniensis, a nonpathogenic amoeba. We analyzed the cytopathic effect of A. mauritaniensis on RCE1(5â¯T5) and MDCK cells and compared it to that of Acanthamoeba castellanii. A partial biochemical characterization of proteases was performed in total crude extracts (TCE) and conditioned medium (CM). Finally, we evaluated the effect of proteases on tight junction (TJ) proteins and the transepithelial electrical resistance of MDCK cells. The results showed that this amoeba can induce substantial damage to RCE1(5T5) and MDCK cells. Moreover, the zymograms and Azocoll assays of amoebic TCE and CM revealed different protease activities, with serine proteases being the most active. Furthermore, A. mauritaniensis induced the alteration and degradation of MDCK cell TJ proteins with serine proteases. After genotyping this amoeba, we determined that it is an isolate of Acanthamoeba genotype T4D. From these data, we suggest that A. mauritaniensis genotype T4D behaves similarly to the A. castellanii strain.
Asunto(s)
Acanthamoeba/genética , Acanthamoeba/patogenicidad , Genotipo , Acanthamoeba/enzimología , Animales , Perros , Células Epiteliales/parasitología , Células Epiteliales/patología , Células de Riñón Canino Madin Darby , Serina Proteasas/metabolismo , Proteínas de Uniones Estrechas/metabolismoRESUMEN
Pathological α-synuclein (α-syn) overexpression and iron (Fe)-induced oxidative stress (OS) are involved in the death of dopaminergic neurons in Parkinson's disease (PD). We have previously characterized the role of triacylglycerol (TAG) formation in the neuronal response to Fe-induced OS. In this work we characterize the role of the α-syn variant A53T during Fe-induced injury and investigate whether lipid metabolism has implications for neuronal fate. To this end, we used the N27 dopaminergic neuronal cell line either untransfected (UT) or stably transfected with pcDNA3 vector (as a transfection control) or pcDNA-A53T-α-syn (A53T α-syn). The overexpression of A53T α-syn triggered an increase in TAG content mainly due to the activation of Acyl-CoA synthetase. Since fatty acid (FA) ß-oxidation and phospholipid content did not change in A53T α-syn cells, the unique consequence of the increase in FA-CoA derivatives was their acylation in TAG moieties. Control cells exposed to Fe-induced injury displayed increased OS markers and TAG content. Intriguingly, Fe exposure in A53T α-syn cells promoted a decrease in OS markers accompanied by α-syn aggregation and elevated TAG content. We report here new evidence of a differential role played by A53T α-syn in neuronal lipid metabolism as related to the neuronal response to OS.
Asunto(s)
Hierro/toxicidad , Neuronas/metabolismo , alfa-Sinucleína/metabolismo , Animales , Línea Celular , Supervivencia Celular/genética , Gotas Lipídicas/metabolismo , Mutación , Neuronas/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Ratas , Especies Reactivas de Oxígeno/metabolismo , Transfección/métodos , Triglicéridos/metabolismo , alfa-Sinucleína/genéticaRESUMEN
Phosphatidylinositol-4 kinase (PI-4K) is responsible for the generation of phosphatidylinositol-4 phosphate (PtdIns(4)P), a bioactive signaling molecule involved in several biological functions. In this study, we show that sphingosine modulates the activity of the PI-4K isoform associated with the basolateral membranes (BLM) from kidney proximal tubules. Immunoblotting with an anti-α subunit PI-4K polyclonal antibody revealed the presence of two bands of 57 and 62kDa in the BLM. BLM-PI-4K activity retains noteworthy biochemical properties; it is adenosine-sensitive, not altered by wortmanin, and significantly inhibited by Ca(2+) at the µM range. Together, these observations indicate the presence of a type II PI-4K. Endogenous phosphatidylinositol (PI) alone reaches PI-4K half-maximal activity, revealing that even slight modifications in PI levels at the membrane environment promote significant variations in BLM-associated-PI-4K activity. ATP-dependence assays suggested that the Mg.ATP(2-) complex is the true substrate of the enzyme and that free Mg(2+) is an essential cofactor. Another observation indicated that higher concentrations of free ATP are inhibitory. BLM-associated-PI-4K activity was ~3-fold stimulated in the presence of increasing concentration of sphingosine, while in concentrations higher than 0.4mM, in which S1P is pronouncedly formed, there was an inhibitory effect on PtdIns(4)P formation. We propose that a tightly coupled regulatory network involving phosphoinositides and sphingolipids participate in the regulation of key physiological processes in renal BLM carried out by PI-4K.
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1-Fosfatidilinositol 4-Quinasa/metabolismo , Membrana Celular/metabolismo , Glicerofosfolípidos/metabolismo , Túbulos Renales Proximales/enzimología , Esfingolípidos/metabolismo , Esfingosina/farmacología , Animales , Immunoblotting , Túbulos Renales Proximales/efectos de los fármacos , Fosforilación/efectos de los fármacos , PorcinosRESUMEN
Persistent activation of GABAA receptors triggers compensatory changes in receptor function that are relevant to physiological, pathological and pharmacological conditions. Chronic treatment of cultured neurons with GABA for 48h has been shown to produce a down-regulation of receptor number and an uncoupling of GABA/benzodiazepine site interactions with a half-time of 24-25h. Down-regulation is the result of a transcriptional repression of GABAA receptor subunit genes and depends on activation of L-type voltage-gated calcium channels. The mechanism of this uncoupling is currently unknown. We have previously demonstrated that a single brief exposure of rat primary neocortical cultures to GABA for 5-10min (t½=3min) initiates a process that results in uncoupling hours later (t½=12h) without a change in receptor number. Uncoupling is contingent upon GABAA receptor activation and independent of voltage-gated calcium influx. This process is accompanied by a selective decrease in subunit mRNA levels. Here, we report that the brief GABA exposure induces a decrease in the percentage of α3-containing receptors, a receptor subtype that exhibits a high degree of coupling between GABA and benzodiazepine binding sites. Initiation of GABA-induced uncoupling is prevented by co-incubation of GABA with high concentrations of sucrose suggesting that it is dependent on a receptor internalization step. Moreover, results from immunocytochemical and biochemical experiments indicate that GABA exposure causes an increase in GABAA receptor endocytosis. Together, these data suggest that the uncoupling mechanism involves an initial increase in receptor internalization followed by activation of a signaling cascade that leads to selective changes in receptor subunit levels. These changes might result in the assembly of receptors with altered subunit compositions that display a lower degree of coupling between GABA and benzodiazepine sites. Uncoupling might represent a homeostatic mechanism that negatively regulates GABAergic transmission under physiological conditions in which synaptic GABAA receptors are transiently activated for several minutes.
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Benzodiazepinas/farmacología , Neuronas/efectos de los fármacos , Receptores de GABA-A/química , Receptores de GABA-A/metabolismo , Ácido gamma-Aminobutírico/farmacología , Animales , Benzodiazepinas/metabolismo , Sitios de Unión/efectos de los fármacos , Células Cultivadas , Corteza Cerebral/citología , Embrión de Mamíferos , Flunitrazepam/farmacocinética , Antagonistas del GABA/farmacología , Moduladores del GABA/farmacocinética , Regulación de la Expresión Génica/efectos de los fármacos , Picrotoxina/farmacología , Unión Proteica/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de GABA-A/genética , Factores de Tiempo , Tritio/farmacocinéticaRESUMEN
Bacterial GatCAB amidotransferases are responsible for the transamidation of mischarged glutamyl-tRNA(Gln) into glutaminyl-tRNA(Gln). Mitochondria matrix also has a multienzymatic complex necessary for the transamidation of glutamyl-tRNA(Gln). Gtf1p, Her2p and Pet112p are the constituents of mitochondrial GatFAB amidotransferase complex. Her2p is subunit A of GatFAB complex, while Gtf1p is subunit F, a connector protein between Pet112p (subunit B) and Her2p. Here we evaluate through molecular modeling and amino acid correlation analysis the HER2 protein family. Localization studies indicated that Her2p is predominantly localized in the mitochondrial outer membrane, but it is also located in the mitochondrial matrix where together with Pet112p and Gtf1p constitutes the GatFAB complex. Finally, HER2 random mutagenesis unveiled important residues that provide thermo stability for the complex and are differently suppressed by overexpression of GTF1 or PET112. For instance, her2/ts11 mutant showed its fermentative growth impaired, and poorly rescued by GTF1 indicating that Her2p unknown function in the mitochondria outer membrane affects cell viability.
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Aminoacil-ARNt Sintetasas/genética , Mitocondrias/enzimología , Proteínas Mitocondriales/genética , Transferasas de Grupos Nitrogenados/genética , Transferasas de Grupos Nitrogenados/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Transaminasas/genética , Aminoacil-ARNt Sintetasas/metabolismo , Supervivencia Celular , Mapeo Cromosómico , Retículo Endoplásmico/metabolismo , Glutamina/genética , Mitocondrias/genética , Mitocondrias/metabolismo , Proteínas Mitocondriales/metabolismo , Modelos Moleculares , Mutación , Aminoacil-ARN de Transferencia/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Alineación de Secuencia , Transaminasas/metabolismoRESUMEN
Iron accumulation and oxidative stress are hallmarks of retinas from patients with age-related macular degeneration (AMD). We have previously demonstrated that iron-overloaded retinas are a good in vitro model for the study of retinal degeneration during iron-induced oxidative stress. In this model we have previously characterized the role of cytosolic phospholipase A2 (cPLA2) and calcium-independent isoform (iPLA2). The aim of the present study was to analyze the implications of Group V secretory PLA2 (sPLA2), another member of PLA2 family, in cyclooxygenase (COX)-2 and nuclear factor kappa B (NF-κB) regulation. We found that sPLA2 is localized in cytosolic fraction in an iron concentration-dependent manner. By immunoprecipitation (IP) assays we also demonstrated an increased association between Group V sPLA2 and COX-2 in retinas exposed to iron overload. However, COX-2 activity in IP assays was observed to decrease in spite of the increased protein levels observed. p65 (RelA) NF-κB levels were increased in nuclear fractions from retinas exposed to iron. In the presence of ATK (cPLA2 inhibitor) and YM 26734 (sPLA2 inhibitor), the nuclear localization of both p65 and p50 NF-κB subunits was restored to control levels in retinas exposed to iron-induced oxidative stress. Membrane repair mechanisms were also analyzed by studying the participation of acyltransferases in phospholipid remodeling during retinal oxidation stress. Acidic phospholipids, such as phosphatidylinositol (PI) and phosphatidylserine (PS), were observed to show an inhibited acylation profile in retinas exposed to iron while phosphatidylethanolamine (PE) showed the opposite. The use of PLA2 inhibitors demonstrated that PS is actively deacylated during iron-induced oxidative stress. Results from the present study suggest that Group V sPLA2 has multiple intracellular targets during iron-induced retinal degeneration and that the specific role of sPLA2 could be related to inflammatory responses by its participation in NF-κB and COX-2 regulation.
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Ciclooxigenasa 2/metabolismo , Fosfolipasas A2 Grupo V/fisiología , Degeneración Macular/metabolismo , FN-kappa B/metabolismo , Estrés Oxidativo/efectos de los fármacos , Retina/efectos de los fármacos , Acetilación , Acetiltransferasas/metabolismo , Animales , Western Blotting , Bovinos , Citosol/metabolismo , Electroforesis en Gel de Poliacrilamida , Inhibidores Enzimáticos/farmacología , Compuestos Ferrosos/toxicidad , Fosfolipasas A2 Grupo V/antagonistas & inhibidores , Sobrecarga de Hierro/metabolismo , Fosfatidiletanolaminas/metabolismo , Fosfatidilinositoles/metabolismo , Fosfatidilserinas/metabolismo , Fosfolipasas A/metabolismo , Fosfolipasas A/fisiología , Retina/metabolismoRESUMEN
The influence of time and temperature on the storage of an alkaline antigen of L. major-like and L.(V.) braziliensis promastigotes added or not of a proteases inhibitor (PMSF) was evaluated by means of an IgG-ELISA. Antibodies in assays using L. major-like antigen stored at -20 degrees C for 6 months had a statistically lower geometric mean titer (GMT) and different 95% confidence interval limits (CL) than antigens stored otherwise, as assessed by the [quot ]t[quot ] statistic. The PMSFL. major-like antigen after storage for 6 months at a temperature of 4 degrees C had the same GMT and 95% CL displayed at time zero as well as when storage for 4 and 6 months at -20 degrees C. Significant differences were not found when L.(V.) braziliensis antigens were stored at times and temperatures mentioned; the PMSF antigen stored for 2 months at -70 degrees C resulted in a lower serum GMT and 95% CL than any other, as assessed by the [quot ]t[quot ] statistic. Antigen performance did not show any statistical difference associated to the addition of PMSF within the same species; the largest difference between antigens was that between PMSF-L. (V.) braziliensis and L. major-like without PMSF.
A influência do tempo e temperatura de estocagem de antígenos alcalinos de promastigotas de L. major-like e L. (V.) braziliensis adicionados ou não de um inibidor de proteases foi avaliada por meio de reações de IgG-ELISA. A reação que empregava o antígeno de L. major-like estocado por 6 meses a -20oC mostrou que médias geométricas dos títulos (MGT)e intervalos de confiança 95% (IC 95%) eram estatisticamente inferiores àquelas obtidas com antígenos estocados em outros intervalos de tempo, medido pela estatística "t". O antígeno PMSF-L. major-like depois de 6 meses de estocagem à temperatura de 4oC tinha a mesma MGT e IC 95% do tempo zero assim como quando ele foi estocado a -20oC por 4 e 6 meses. Não foram observadas diferenças estatisticamente diferentes com os antígenos de L. (V.) braziliensis estocados nas mesmas condições de tempo e temperatura exceto o antígeno PMSF estocado por 2 meses a -70oC que apresentou MGT e IC 95% inferiores a quaisquer outras como aferido pela estatísitca "t". Quando comparados os desempenhos dos antígenos não houve direrenças estatisticamente significantes entre a adição ou não de PMSF para qualquer dos parasitas. A análise do cruzamento entre antígenos mostrou que a maior diferença netre eles foi a do contraste entre L. (V.) braziliensis adicionado de PMSF e L. major-like sem adição de PMSF.