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1.
J Sci Food Agric ; 104(2): 1039-1050, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-37743412

RESUMEN

BACKGROUND: Withering is the first processing procedure of beauty tea, and there are few reports on the impact of withering methods on the quality of beauty tea and its regulatory mechanisms. RESULTS: Through comparison of fresh tea leaves (FT) with the leaves after indoor natural withering for 18 h (IWT-18) and outdoor solar withering for 6 h (OWT-6), which were collected at the end of the two withering processes, 17 282 and 13 984 differentially expressed genes (DEGs) were respectively screened and 267 and 154 differential metabolites (DMs) were respectively identified. The coexpression network revealed that a large number of DEGs and DMs were enriched in phenylpropanoid, flavonoid, and adenosine triphosphate binding cassette (ABC) transporter pathways, and the number of DMs and DEGs in IWT-18 versus FT exceeded that in OWT-6 versus FT. Both withering methods promoted a significant increase in content of phenylalanine and upregulation of ß-glucoside expression in the phenylpropanoid metabolism pathway. Five theaflavin-type proanthocyanidins in the flavonoid synthesis pathway were more significantly accumulated in FT versus IWT-18 than in FT versus OWT-6. Meanwhile, both withering methods can affect the ABC transporter pathway to promote the accumulation of amino acids and their derivatives, but different withering methods affect different ABC transporter families. Outdoor withering with more severe abiotic stress has a greater impact on the ABCG family, whereas indoor withering has a more significant effect on the ABCC family. Sensory evaluation results showed that the dry tea of IWT-18 was slightly better than that of OWT-6 because of the longer withering time and more thorough substance transformation. CONCLUSION: In conclusion, the formation of honey flavor in beauty tea may be closely related to the DEGs and DMs in these three pathways. Our research provides theoretical data support for further revealing the mechanism of quality formation during the withering process of beauty tea. © 2023 Society of Chemical Industry.


Asunto(s)
Camellia sinensis , Camellia sinensis/química , Transcriptoma , Belleza , Metaboloma , Flavonoides/análisis , Té/química , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/metabolismo , Hojas de la Planta/química
2.
Br J Nutr ; 120(5): 537-548, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30043720

RESUMEN

Rats with a normal birth weight (NBW) or intra-uterine growth retardation (IUGR) were fed basic diets (NBW and IUGR groups) or basic diets supplemented with curcumin (NC and IC groups) from 6 to 12 weeks. The body weight of IUGR rats was lower (P<0·05) than that of the controls. Rats with IUGR showed higher (P<0·05) concentrations of TNF-α, IL-1ß and IL-6; higher (P<0·05) activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in their serum; and increased (P<0·05) concentrations of malondialdehyde (MDA), protein carbonyl (PC) and 8-hydroxy-2'-deoxyguanosine (8-OHDG) in the liver compared with the NBW rats. The livers of IUGR rats exhibited a lower (P<0·05) superoxide dismutase activity and decreased (P<0·05) metabolic efficiency of the hepatic glutathione redox cycle compared with those of the NBW rats. In response to dietary curcumin supplementation, concentrations of inflammatory cytokines and activities of AST and ALT in the serum and MDA, PC and 8-OHDG in the liver were lower (P<0·05), and the hepatic glutathione redox cycle in the liver was improved (P<0·05) in the IC group than in the IUGR group. These results were associated with lower (P<0·05) phosphorylated levels of the NF-κB pathway and Janus kinase 2 (JAK2) and higher (P<0·05) mRNA expression of genes involved in the nuclear factor, erythroid 2-like 2 (Nfe2l2)/antioxidant response element (ARE) pathway in the liver of the IC rats than that of the IUGR rats. Maternal undernutrition decreased birth weight and led to inflammation, oxidative damage and injury in rats. Curcumin appeared to be beneficial in preventing IUGR-induced inflammation, oxidative damage and injury by activating the expression of the NF-κB, JAK/STAT and Nfe2l2/ARE pathways in the liver.


Asunto(s)
Curcumina/administración & dosificación , Retardo del Crecimiento Fetal/fisiopatología , Inflamación/prevención & control , Hepatopatías/prevención & control , Estrés Oxidativo/efectos de los fármacos , 8-Hidroxi-2'-Desoxicoguanosina , Transportadoras de Casetes de Unión a ATP/análisis , Alanina Transaminasa/sangre , Animales , Animales Recién Nacidos , Aspartato Aminotransferasas/sangre , Peso al Nacer , Proteínas de Caenorhabditis elegans/análisis , Citocinas/sangre , Citocinas/genética , Desoxiguanosina/análogos & derivados , Desoxiguanosina/análisis , Suplementos Dietéticos , Modelos Animales de Enfermedad , Femenino , Expresión Génica/efectos de los fármacos , Inflamación/sangre , Inflamación/etiología , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Hepatopatías/etiología , Hepatopatías/metabolismo , Oxidación-Reducción , Embarazo , Ratas
3.
Biochem Biophys Res Commun ; 473(2): 593-9, 2016 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-27033603

RESUMEN

Living in an enriched housing environment is an established model of eustress and has been consistently shown to reduce the growth of transplanted tumors, including pancreatic cancer. Here, we further investigate the influence of an enriched environment (EE) on the efficacy of chemotherapy in pancreatic cancer. Male C57BL/6 mice were housed in EE or standard environment (SE) conditions and transplanted with syngeneic Panc02 pancreatic cancer cells. Tumor-bearing mice were treated with 5-fluorouracil (5-FU) or gemcitabine (GEM) to examine their sensitivities to chemotherapy. The results showed that both 5-FU and GEM exerted the dose dependent inhibition of tumor growth. The tumor inhibition rates of low-dose 5-FU and GEM were improved from 17.7% and 23.6% to 46.3% and 49.9% by EE housing. Importantly, tumor cells isolated from the pancreatic cancer xenografts of EE mice had significantly enhanced sensitivities to both 5-FU and GEM (IC50 for 5-FU: 2.8 µM versus 27.3 µM; IC50 for GEM: 0.8 µM versus 5.0 µM). Furthermore, using microarray analyses, we identified the "ATP-binding cassette (ABC) transporter" that was overrepresented among EE-induced down-regulated genes in pancreatic cancer. Particularly, the tumoral expression of ABC transporter A8b (ABCA8b) was confirmed to be significantly decreased by EE. Over-expression of ABCA8b in mouse pancreatic cancer cells led to a marked decrease in the sensitivity to chemotherapeutic drugs both in vitro and in vivo. In conclusion, our data indicate that benign stressful stimulation can synergistically boost the efficiency of chemotherapeutics in pancreatic cancer, which suggests a novel strategy for adjuvant cancer therapy.


Asunto(s)
Antineoplásicos/uso terapéutico , Desoxicitidina/análogos & derivados , Fluorouracilo/uso terapéutico , Páncreas/efectos de los fármacos , Neoplasias Pancreáticas/tratamiento farmacológico , Transportadoras de Casetes de Unión a ATP/análisis , Animales , Desoxicitidina/uso terapéutico , Vivienda para Animales , Masculino , Ratones Endogámicos C57BL , Páncreas/patología , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/psicología , Estrés Psicológico , Gemcitabina
4.
Zhongguo Zhong Yao Za Zhi ; 40(3): 533-7, 2015 Feb.
Artículo en Chino | MEDLINE | ID: mdl-26084183

RESUMEN

The formation of macrophage-derived foam cells is a typical feature of atherosclerosis (AS). Reverse cholesterol efflux (RCT) is one of important factors for the formation of macrophage foam cells. In this study, macrophage form cells were induced by oxidized low density lipoprotein (ox-LDL) and then treated with different concentrations of ferulic acid, so as to observe the effect of ferulic acid on the intracellular lipid metabolism in the ox-LDL-induced macrophage foam cell formation, the cholesterol efflux and the mRNA expression and protein levels of ATP binding cassette transporter A1 (ABCA1) and ATP binding cassette transporter G1 (ABCG1) that mediate cholesterol efflux, and discuss the potential mechanism of ferulic acid in resisting AS. According to the findings, compared with the control group, the ox-LDL-treated group showed significant increase in intracellular lipid content, especially for the cholesterol content; whereas the intracellular lipid accumulation markedly decreased, after the treatment with ferulic acid. The data also demonstrated that the mRNA and protein expressions of ABCA1 and ABCG1 significantly increased after macrophage foam cells were treated with different concentrations of ferulic acid. In summary, ferulic acid may show the anti-atherosclerosis effect by increasing the surface ABCA1 and ABCG1 expressions of macrophage form cells and promoting cholesterol efflux.


Asunto(s)
Colesterol/metabolismo , Ácidos Cumáricos/farmacología , Células Espumosas/efectos de los fármacos , Transportador 1 de Casete de Unión a ATP/análisis , Transportador 1 de Casete de Unión a ATP/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1 , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/genética , Animales , Células Cultivadas , Células Espumosas/metabolismo , Lipoproteínas/análisis , Lipoproteínas/genética , Ratones
5.
Plant Cell ; 26(8): 3403-15, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25122151

RESUMEN

The lipid biopolymer suberin plays a major role as a barrier both at plant-environment interfaces and in internal tissues, restricting water and nutrient transport. In potato (Solanum tuberosum), tuber integrity is dependent on suberized periderm. Using microarray analyses, we identified ABCG1, encoding an ABC transporter, as a gene responsive to the pathogen-associated molecular pattern Pep-13. Further analyses revealed that ABCG1 is expressed in roots and tuber periderm, as well as in wounded leaves. Transgenic ABCG1-RNAi potato plants with downregulated expression of ABCG1 display major alterations in both root and tuber morphology, whereas the aerial part of the ABCG1-RNAi plants appear normal. The tuber periderm and root exodermis show reduced suberin staining and disorganized cell layers. Metabolite analyses revealed reduction of esterified suberin components and hyperaccumulation of putative suberin precursors in the tuber periderm of RNA interference plants, suggesting that ABCG1 is required for the export of suberin components.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/fisiología , Lípidos/biosíntesis , Proteínas de Plantas/fisiología , Solanum tuberosum/metabolismo , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Transporte Biológico/genética , Membrana Celular/metabolismo , Regulación de la Expresión Génica de las Plantas , Análisis de Secuencia por Matrices de Oligonucleótidos , Proteínas de Plantas/análisis , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Interferencia de ARN , Solanum tuberosum/genética
6.
Biol Pharm Bull ; 34(10): 1624-7, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21963506

RESUMEN

Coffee is a beverage that is consumed world-wide on a daily basis and is known to induce a series of metabolic and pharmacological effects, especially in the digestive tract. However, little is known concerning the effects of coffee on transporters in the gastrointestinal tract. To elucidate the effect of coffee on intestinal transporters, we investigated its effect on expression of the breast cancer resistance protein (BCRP/ABCG2) in a human colorectal cancer cell line, Caco-2. Coffee induced BCRP gene expression in Caco-2 cells in a coffee-dose dependent manner. Coffee treatment of Caco-2 cells also increased the level of BCRP protein, which corresponded to induction of gene expression, and also increased cellular efflux activity, as judged by Hoechst33342 accumulation. None of the major constituents of coffee tested could induce BCRP gene expression. The constituent of coffee that mediated this induction was extractable with ethyl acetate and was produced during the roasting process. Dehydromethylepoxyquinomicin (DHMEQ), an inhibitor of nuclear factor (NF)-κB, inhibited coffee-mediated induction of BCRP gene expression, suggesting involvement of NF-κB in this induction. Our data suggest that daily consumption of coffee might induce BCRP expression in the gastrointestinal tract and may affect the bioavailability of BCRP substrates.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Neoplasias de la Mama/metabolismo , Café , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Extractos Vegetales/farmacología , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2 , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/biosíntesis , Transportadoras de Casetes de Unión a ATP/genética , Benzamidas/farmacología , Bencimidazoles/farmacología , Neoplasias de la Mama/genética , Células CACO-2 , Técnicas de Cultivo de Célula , Ciclohexanonas/farmacología , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Femenino , Expresión Génica/efectos de los fármacos , Humanos , Terapia Molecular Dirigida , FN-kappa B/antagonistas & inhibidores , FN-kappa B/genética , Proteínas de Neoplasias/análisis , Proteínas de Neoplasias/metabolismo
7.
J Cardiovasc Pharmacol ; 57(3): 325-33, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21164355

RESUMEN

Apolipoprotein A-I (ApoA-I)/high-density lipoprotein (HDL)-raising treatments are effective antiatherosclerotic strategies. We have compared the antiatherogenic effects of human ApoA-I (hApoA-I) overexpression by intraportal and intramuscular gene transfer in atherosclerotic ApoE-knockout mice. Atherosclerotic lesions were induced by atherogenic diet. After atherosclerosis induction, a group of animals was killed and served as atherosclerosis baseline-control group. The remaining animals were randomized into the following groups: (1) atherosclerosis-progression-control, (2) intraportal/vector administration, and (3) intramuscular/vector administration. Aortas and hearts were processed for atherosclerotic quantification by en face Sudan IV and Oil Red-O, respectively. Liver and muscle specimens were processed for protein/gene expression analysis. A sustained increase in hApoA-I/HDL plasma levels was observed in both transduced groups. hApoA-I overexpression abolished plaque progression versus progression-control group. hApoA-I overexpression significantly reduced lesion macrophage, feature indicative of plaque stabilization. Scavenger receptor class-B type I (SR-BI), but not ATP-binding cassette, sub-family A (ABCA), member 1 (ABCA-1), was significantly upregulated in treated groups versus progression-controls. The results of this study show a similar effect of hApoA-I/HDL overexpression on plaque progression/stabilization by 2 different routes of administration. Our results showing similar effects using either intramuscular administration and intraportal route of administration may have significant clinical implications, given the reduced medical risk to patient and cost of intramuscular injections.


Asunto(s)
Aorta/efectos de los fármacos , Apolipoproteína A-I/genética , Apolipoproteína A-I/uso terapéutico , Apolipoproteínas E/genética , Aterosclerosis/tratamiento farmacológico , Dependovirus/metabolismo , Hígado/efectos de los fármacos , Transportador 1 de Casete de Unión a ATP , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/genética , Animales , Aorta/patología , Apolipoproteína A-I/administración & dosificación , Apolipoproteína A-I/sangre , Apolipoproteínas E/metabolismo , Aterosclerosis/genética , Aterosclerosis/metabolismo , Aterosclerosis/patología , HDL-Colesterol/sangre , Dependovirus/genética , Dieta Aterogénica , Progresión de la Enfermedad , Evaluación Preclínica de Medicamentos , Vectores Genéticos , Humanos , Inyecciones Intramusculares , Inyecciones Intravenosas , Hígado/anatomía & histología , Hígado/fisiopatología , Ratones , Ratones Noqueados , Terapia Molecular Dirigida , Receptores Depuradores de Clase B/análisis , Receptores Depuradores de Clase B/genética , Factores de Tiempo , Transducción Genética
8.
Int J Cancer ; 120(5): 1141-9, 2007 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-17131346

RESUMEN

High levels of PDGFR expression in primary rhabdomyosarcoma (RMS) have been associated with disease progression. To date however, there are no reports on the activity of imatinib mesylate, a selective PDGFR inhibitor, in RMS preclinical models. A panel of 5 RMS cell lines was used to investigate the expression of PDGFRalpha and PDGFRbeta, c-Kit and the multidrug transporter ABCG2 (also inhibited by imatinib). In vitro and in vivo experiments were performed using RD (embryonal) and RH30 (alveolar) cell lines to determine the efficacy of imatinib as single agent and in combination with topotecan (TPT). PDGFRbeta was significantly expressed in all cell lines, with the highest levels in RD, while PDGFR alpha and ABCG2 were significantly expressed only in RH30 and RMZ-RC2. c-Kit was not detected. PDGFRbeta signaling was active in RD but not in RH30, whilst PDGFRalpha signaling was not active in either cell lines. Significant ABCG2-mediated extrusion of Hoechst 33342 was demonstrated in RH30 but not in RD, and was inhibited by imatinib and the specific ABCG2 inhibitor Ko143. In vitro, imatinib was not active as a single agent at therapeutic concentrations, but significantly potentiated TPT antitumor activity in both cell lines. In vivo experiments using tumor xenografts confirmed the synergistic interaction in both cell lines. These results suggest that at least 2 different mechanisms--inhibition of ABCG2 and/or PDGFRbeta--are involved in the synergistic interaction between imatinib and TPT, and support the use of this combination for the treatment of high-risk RMS patients.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica , Piperazinas/uso terapéutico , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirimidinas/uso terapéutico , Rabdomiosarcoma/tratamiento farmacológico , Topotecan/uso terapéutico , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2 , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/antagonistas & inhibidores , Transportadoras de Casetes de Unión a ATP/genética , Animales , Benzamidas , Línea Celular Tumoral , Evaluación Preclínica de Medicamentos , Humanos , Mesilato de Imatinib , Ratones , Ratones Desnudos , Proteínas de Neoplasias/análisis , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/genética , Proteínas Proto-Oncogénicas c-kit/análisis , Proteínas Proto-Oncogénicas c-kit/genética , ARN Mensajero/análisis , ARN Mensajero/metabolismo , Receptores del Factor de Crecimiento Derivado de Plaquetas/análisis , Receptores del Factor de Crecimiento Derivado de Plaquetas/antagonistas & inhibidores , Receptores del Factor de Crecimiento Derivado de Plaquetas/genética , Ensayos Antitumor por Modelo de Xenoinjerto
9.
Br J Nutr ; 95(3): 618-22, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16512948

RESUMEN

An increased activity of ATP-binding cassette transporter (ABC) A1 has been proposed as a mechanism underlying the hypocholesterolaemic effect of phytosterols. In the present study, ABCA1-deficient mice (ABCA1-/- mice) were used to examine the involvement of the ABCA1 in the reduction of intestinal cholesterol absorption in response to a phytosterol-enriched diet. A decrease in intestinal cholesterol absorption of 39 and 35 % was observed after phytosterol treatment in ABCA1+/+ mice and in ABCA1-/- mice, respectively. No statistically significant changes in plasma lipoprotein profile or in intestinal ABCG5, ABCG8 and Niemann-Pick C1-Like 1 gene expression levels were found when phytosterol-treated ABCA1-/- mice and untreated ABCA1-/- mice were compared. We conclude that phytosterol inhibition of cholesterol absorption in mice is independent of ABCA1.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Colesterol en la Dieta/farmacocinética , Suplementos Dietéticos , Mucosa Intestinal/metabolismo , Fitosteroles/administración & dosificación , Transportador 1 de Casete de Unión a ATP , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5 , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8 , Transportadoras de Casetes de Unión a ATP/análisis , Absorción , Animales , Expresión Génica , Lipoproteínas/análisis , Proteínas de Transporte de Membrana/análisis , Ratones , Ratones Endogámicos DBA , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos
10.
Mol Psychiatry ; 6(4): 380-6, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11443521

RESUMEN

We show here that clozapine, a beneficial antipsychotic, down-regulates the expression of the glutamate transporter GLT-1 in the rat cerebral cortex, thereby reducing glutamate transport and raising extracellular glutamate levels. Clozapine treatment (25--35 mg kg(-1) day(-1) orally) reduced GLT-1 immunoreactivity in several brain regions after 3 weeks; this effect was most prominent after 9 weeks and most evident in the frontal cortex. GLT-1 protein levels were reduced in the cerebral cortex of treated rats compared with controls and were more severely affected in the anterior (71.9 +/- 4.5%) than in the posterior (53.2 +/- 15.4%) cortex. L-[(3)H]-glutamate uptake in Xenopus laevis oocytes injected with mRNA extracted from the anterior cerebral cortex of rats treated for 9 weeks was remarkably reduced (to 30.6 +/- 8.6%) as compared to controls. In addition, electrophysiological recordings from oocytes following application of glutamate revealed a strong reduction in glutamate uptake currents (46.3 +/- 10.2%) as compared to controls. Finally, clozapine treatment led to increases in both the mean basal (8.1 +/- 0.7 microM) and the KCl-evoked (28.7 +/- 7.7 microM) output of glutamate that were 3.1 and 3.5, respectively, higher than in control rats. These findings indicate that clozapine may potentiate glutamatergic synaptic transmission by regulating glutamate transport.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/genética , Corteza Cerebral/metabolismo , Clozapina/farmacología , Lóbulo Frontal/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Ácido Glutámico/metabolismo , Transportadoras de Casetes de Unión a ATP/análisis , Sistema de Transporte de Aminoácidos X-AG , Animales , Antipsicóticos/farmacología , Corteza Cerebral/efectos de los fármacos , Femenino , Lóbulo Frontal/efectos de los fármacos , Técnicas In Vitro , Microdiálisis , Oocitos/efectos de los fármacos , Oocitos/fisiología , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/metabolismo , Xenopus laevis
11.
Eur J Med Res ; 5(12): 517-22, 2000 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-11147995

RESUMEN

Aim of the present study was to establish a cell system to study the physiological function of human MDR3 P-glycoprotein in cellular phosphatidylcholine (PC) secretion. MDR3 cDNA was expressed in HeLa cells using the tet-off system together with a luciferase reporter gene. MDR3 Pgp expression was turned on upon removal of doxycycline as shown by Western blot analysis. Immunohistochemistry using a specific anti human MDR3 Pgp antibody revealed a prominent staining of MDR3 Pgp covering the cytoplasm and the area of the plasma membrane. In presence of doxycycline MDR3 Pgp expression was turned off. For analysis of PC secretory activity, MDR3 Pgp expressing and non-expressing cells as well as control HeLa cells with low endogenous MDR3 were preincubated with [(3)H]choline for synthesis of cellular [(3)H]PC. Cells were then incubated for 2 h in media with 0-4 mM taurocholate (TC) and release of cellular [(3)H]PC was recorded. [(3)H]PC secretion was observed in presence of TC without impairing cell viability. There was a significant increase in [(3)H]PC excretion in MDR3 Pgp expressing cells compared to non-expressing controls (e.g. 4.5 fold at 4 mM TC), revealing a high efficiency of transport activity (turnover). From the data it is concluded that the MDR3 Pgp expressing cell system under control of a doxycycline responsive promotor is functionally active and provides a tool to further study MDR3 Pgp mediated transport.


Asunto(s)
Subfamilia B de Transportador de Casetes de Unión a ATP/análisis , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/análisis , Transportadoras de Casetes de Unión a ATP/genética , Antibacterianos/farmacología , Doxiciclina/farmacología , Resistencia a Múltiples Medicamentos/genética , Regulación de la Expresión Génica/efectos de los fármacos , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Transporte Biológico/efectos de los fármacos , Transporte Biológico/fisiología , Western Blotting , Bloqueadores de los Canales de Calcio/farmacología , Colina/farmacocinética , Clonación Molecular , Ciclosporinas/farmacología , ADN Complementario , Regulación de la Expresión Génica/fisiología , Células HeLa , Hepatocitos/citología , Hepatocitos/metabolismo , Humanos , Inmunohistoquímica , Luciferasas/genética , Fosfatidilcolinas/metabolismo , Conejos , Ácido Taurocólico/metabolismo , Tritio , Verapamilo/farmacología
12.
Mol Pharmacol ; 53(3): 355-69, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9495799

RESUMEN

Sodium-dependent transport into astrocytes is critical for maintaining the extracellular concentrations of glutamate below toxic levels in the central nervous system. In this study, the expression of the glial glutamate transporters GLT-1 and GLAST was studied in primary cultures derived from cortical tissue. In primary astrocytes, GLAST protein levels were approximately one half of those observed in cortical tissue, but GLT-1 protein was present at very low levels compared with cortical tissue. Maintenance of these astrocytes in medium supplemented with dibutyryl-cAMP (dbcAMP) caused a dramatic change in cell morphology, increased GLT-1 and GLAST mRNA levels approximately 5-fold, increased GLAST protein approximately 2-fold, and increased GLT-1 protein >/=8-20-fold. These increases in protein expression were accompanied by 2-fold increases in the Vmax and Km values for Na+-dependent L-[3H]glutamate transport activity. Although GLT-1 is sensitive to inhibition by dihydrokainate in heterologous expression systems, no dihydrokainate sensitivity was observed in astrocyte cultures that expressed GLT-1. Biotinylation with a membrane-impermeant reagent, separation of the biotinylated/cell surface proteins, and subsequent Western blotting demonstrated that both GLT-1 and GLAST were present at the cell surface. Coculturing of astrocytes with neurons also induced expression of GLT-1, which colocalized with the glial specific marker, glial fibrillary acidic protein. Neurons induced a small increase in GLAST protein. Several studies were performed to examine the mechanism by which neurons regulate expression of the glial transporters. Three different protein kinase A (PKA) antagonists did not block the effect of neurons on glial expression of GLT-1 protein, but the addition of dbcAMP to mixed cultures of neurons and astrocytes did not cause GLT-1 protein to increase further. This suggests that neurons do not regulate GLT-1 by activation of PKA but that neurons and dbcAMP regulate GLT-1 protein through convergent pathways. As was observed with GLT-1, the increases in GLAST protein observed in cocultures were not blocked by PKA antagonists, but unlike GLT-1, the addition of dbcAMP to mixed cultures of neurons and astrocytes caused GLAST protein to increase approximately 2-fold. Neurons separated from astrocytes with a semipermeable membrane increased GLT-1 protein, indicating that the effect of neurons was mediated by a diffusible molecule. Treatment of cocultures with high concentrations of either N-methyl-D-aspartate or glutamate killed the neurons, caused GLT-1 protein to decrease, and caused GLAST protein to increase. These studies suggest that GLT-1 and GLAST protein are regulated independently in astrocyte cultures and that a diffusible molecule secreted by neurons induces expression of GLT-1 in astrocytes.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/análisis , AMP Cíclico/fisiología , Neuroglía/química , Neuronas/fisiología , Sodio/fisiología , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Sistema de Transporte de Aminoácidos X-AG , Animales , Células Cultivadas , Ácido Glutámico/metabolismo , Inmunohistoquímica , Peso Molecular , ARN Mensajero/análisis , Ratas
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