RESUMEN
BACKGROUND/PURPOSE: Skin aging has been focused the wrinkle on the face than on the body, so most studies have been studied the change in Crow's feet for ages. Only little is known about the age-dependent changes of wrinkles on body sites. The aim of this study was to establish new grading criteria for severity of wrinkles on knees and to investigate the relationship of wrinkle severity with age- and site-dependent. METHODS: The skin on the knee of 38 healthy Korean female volunteers, divided into two groups young and old, were photographed. Standard photograph for body wrinkle was established (grade 0~7), and then visual assessment, skin wrinkle, and skin elasticity were evaluated on Crow's feet and the knee. We examined for any significant differences and the correlation of skin aging parameters with age and two different sites. RESULTS: Skin wrinkle severity with standard photograph and wrinkle parameters (Ra, Rmax, Rz, and Rv) had a significantly positive correlation with age-dependent on the knee (P < 0.001). Also, skin elastic parameters (R2, R5, R6, R7, and Q1) showed a significant negative correlation with age on the knee (P < 0.001). Skin wrinkle severity with standard photograph was highly correlated with all skin wrinkle parameters and skin elastic parameters (R2, R5, R7, and Q1) on the knee (P < 0.001). In addition, all the skin aging parameters on the knee were significantly correlated with Crow's feet (P < 0.01). Skin aging on the knee had the same tendency as the Crow's feet. CONCLUSIONS: This study has shown the new grading criteria of wrinkles on the knee. Skin wrinkle and elasticity on the knee are age-dependent related and aging on the knee is highly related to Crow's feet. Those parameters are using a quantitative method to evaluate body aging. Also, the knee is considered that it could be a suitable site to evaluate body aging.
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Envejecimiento/patología , Envejecimiento/fisiología , Cara/patología , Cara/fisiología , Rodilla/fisiología , Envejecimiento de la Piel/fisiología , Adiposidad/fisiología , Adulto , Anciano , Ingeniería Biomédica/métodos , Dermoscopía/métodos , Módulo de Elasticidad/fisiología , Femenino , Humanos , Imagenología Tridimensional/métodos , Rodilla/patología , Persona de Mediana EdadRESUMEN
Quantitative reverse-transcription polymerase chain reaction (RT-PCR) and Western blot analyses were carried out to investigate the regulation of genes responsible for the transport and metabolism of drugs in response to different levels of salt intake. A high-salt diet compared with medium- and low-salt diets reduced the expression levels of the mdr1a and mdr1b genes in the liver and kidney, but increased their expression levels in the duodenum, jejunum, and ileum. Likewise, the expression levels of other transporters and CYP3a3 genes varied in different tissues. The expression levels of nuclear receptors, such as Pxr, Fxr, and Car, were also modulated differently in the liver, kidney, and intestines. The protein levels of Mdr1, Oct1, CYP3a, Pxr, Fxr, and Car were correlated with the changes in mRNA levels of the respective genes. In conclusion, the changes in the expression of drug transporters, metabolic enzymes, and nuclear receptors were tissue specific.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Citocromo P-450 CYP3A/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Cloruro de Sodio Dietético/farmacología , Transportadoras de Casetes de Unión a ATP/genética , Animales , Citocromo P-450 CYP3A/genética , Íleon/efectos de los fármacos , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Masculino , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores Citoplasmáticos y Nucleares/genéticaRESUMEN
DNA-dependent protein kinase (DNA-PK) is composed of a 460-kDa catalytic subunit and the regulatory subunits Ku70 and Ku80. The complex is activated on DNA damage and plays an essential role in double-strand-break repair and V(D)J recombination. In addition, DNA-PK is involved in S-phase checkpoint arrest following irradiation, although its role in damage-induced checkpoint arrest is not clear. In an effort to understand the role of DNA-PK in damage signaling, human and mouse cells containing the DNA-PK catalytic subunit (DNA-PKcs proficient) were compared with those lacking DNA-PKcs for c-Jun N-terminal kinase (JNK) activity that mediates physiologic responses to DNA damage. The DNA-PKcs-proficient cells showed much tighter regulation of JNK activity after DNA damage, while the level of JNK protein in both cell lines remained unchanged. The JNK proteins physically associated with DNA-PKcs and Ku70/Ku80 heterodimer, and the interaction was significantly stimulated after DNA damage. Various JNK isoforms not only contained a DNA-PK phosphorylation consensus site (serine followed by glutamine) but also were phosphorylated by DNA-PK in vitro. Together, our results suggest that DNA damage induces physical interaction between DNA-PK and JNK, which may in turn negatively affect JNK activity through JNK phosphorylation by DNA-PK.
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Proteínas de Unión al ADN , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Estrés Fisiológico/enzimología , Animales , Línea Celular , Daño del ADN , Reparación del ADN , Proteína Quinasa Activada por ADN , Activación Enzimática , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos , Ratones , Proteína Quinasa 10 Activada por Mitógenos , Proteína Quinasa 8 Activada por Mitógenos , Proteína Quinasa 9 Activada por Mitógenos , Proteínas Nucleares , Fosforilación , Proteínas Tirosina Quinasas/metabolismoRESUMEN
Several studies have demonstrated that inhibitors of cyclooxygenase (COX) attenuate various neuronal injuries and age-dependent demented conditions. From these findings, we proposed to test the effect of age on COX activity and its possible suppression by the antiaging action of dietary restriction in the rat brain. The status of reactive oxygen species (ROS) was also assessed to correlate with COX activity to delineate the underlying mechanism of the altered COX activity during aging. These results showed that COX activity significantly increased in 24-month-old rats compared with 6-month-old rats in an ad libitum group. Interestingly, mRNA and protein levels of COX-2 showed little corresponding age-related change. The formation of ROS was found to increase gradually with age in ad libitum fed rats. However, dietary restriction suppressed the increase at the age of 24 months. To substantiate the relationship between ROS and COX activity when the rats were 24 months of age, we conducted in vitro experiments with a C6 glioma cell line. Together, it is concluded that increased COX activity with age is due to the activation of COX catalytic reaction by ROS without increased gene expression of COX-2 and that it is related to the increased pro-oxidant status in aged rats.
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Envejecimiento/fisiología , Dieta , Dinoprostona/metabolismo , Prostaglandina-Endoperóxido Sintasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Telencéfalo/enzimología , Factores de Edad , Animales , Secuencia de Bases , Western Blotting , Técnicas de Cultivo , Masculino , Modelos Animales , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , ARN Mensajero/análisis , Ratas , Ratas Wistar , Sensibilidad y EspecificidadRESUMEN
D-raf, a Drosophila homolog of the raf proto-oncogene, has diverse functions throughout development and is transcribed in a wide range of tissues, with high levels of expression in the ovary and in association with rapid proliferation. The expression pattern resembles those of S phase genes, which are regulated by E2F transcription factors. In the 5'-flanking region of D-raf, four sequences (E2F sites 1-4) similar to the E2F recognition sequence were found, one of them (E2F site 3) being recognized efficiently by Drosophila E2F (dE2F) in vitro. Transient luciferase expression assays confirmed activation of the D-raf gene promoter by dE2F/dDP. Expression of Draf-lacZ was greatly reduced in embryos homozygous for the dE2F mutation. These results suggest that dE2F is likely to be an important regulator of D-raf transcription.
Asunto(s)
Proteínas Portadoras , Proteínas de Ciclo Celular , Proteínas de Drosophila , Drosophila melanogaster/embriología , Drosophila melanogaster/genética , Regulación del Desarrollo de la Expresión Génica , Proteínas Proto-Oncogénicas c-raf/genética , Transactivadores , Factores de Transcripción/metabolismo , Transcripción Genética/genética , Animales , Secuencia de Bases , Unión Competitiva , Sondas de ADN/genética , Sondas de ADN/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción E2F , Embrión no Mamífero/metabolismo , Genes Reporteros/genética , Hibridación in Situ , Mutación/genética , Regiones Promotoras Genéticas/genética , Unión Proteica , ARN Mensajero/análisis , ARN Mensajero/genética , Proteínas Recombinantes de Fusión/metabolismo , Elementos de Respuesta/genética , Proteína 1 de Unión a Retinoblastoma , Factores de Transcripción/genética , Activación TranscripcionalRESUMEN
Previous studies have shown that dexamethasone, a synthetic glucocorticoid, can induce a G1 arrest, however, genistein, a natural isoflavonoid phytoestrogen, induces a G2/M arrest in the cell cycle progression in various cancer cell lines. A block of cell cycle checkpoint by dexamethasone and genistein correlates with a selective induction of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1 in a tumor suppressor p53-independent manner and abolishment of Cdk2 phosphorylation. In the present study, the effects of dexamethasone and genistein (both singly and combined) on the expression of p21 in human hepatocellular Hep G2 and colorectal Colo320 HSR carcinoma cells were evaluated. Whereas dexamethasone mildly induced the level of p21 protein, genistein strongly increased the expression of p21 protein in our experimental condition. Both compounds also activated p21 promoter reporter constructs. The combined effects of dexamethasone and genistein on the induction of p21 protein and activation of p21 promoter were synergistic in both cell lines. These findings indicate that dexamethasone and genistein act in a synergistic fashion and have potential for combination chemotherapy for the treatment of liver and colon cancer.
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Anticarcinógenos/farmacología , Antineoplásicos Hormonales/farmacología , Carcinoma Hepatocelular/metabolismo , Neoplasias Colorrectales/metabolismo , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Ciclinas/biosíntesis , Dexametasona/farmacología , Genisteína/farmacología , Neoplasias Hepáticas/metabolismo , Western Blotting , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/patología , División Celular/efectos de los fármacos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/genética , Sinergismo Farmacológico , Electroforesis en Gel de Agar , Citometría de Flujo , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/patología , Luciferasas/metabolismo , Regiones Promotoras Genéticas , ARN Mensajero/análisis , Sales de Tetrazolio , Tiazoles , Transfección , Células Tumorales Cultivadas/efectos de los fármacos , beta-Galactosidasa/metabolismoRESUMEN
Hypoxia is a well-known signal for angiogenesis, but the recent proposal that hypoxia exists in developing embryonic tissues and that it induces vascular development remains to be proven. In the present study, we demonstrate the presence of hypoxia in normal developing embryos by means of a hypoxia marker, pimonidazole, and its associated antibody. Our data clearly show that hypoxia marker immunoreactivity was highly detected in developing neural tubes, heart, and intersomitic mesenchyme at an early stage of organogenesis, suggesting that hypoxia may exist in the early stages of embryo development. We also found that hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) were spatiotemporally co-localized with possible hypoxic regions in embryos. Investigation of platelet endothelial cell adhesion molecule (PECAM) expression provides evidence that endothelial cells proliferate and form the vessels in the hypoxic region in developing organs. Furthermore, we found that hypoxia induced both HIF-1alpha and VEGF in F9 embryonic stem and differentiated cells. Thus, we suggest that hypoxia may exist widely in developing embryonic tissues and that it may act as a signal for embryonic blood vessel formation in vivo.
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Vasos Sanguíneos/embriología , Encéfalo/embriología , Proteínas de Unión al ADN/genética , Desarrollo Embrionario y Fetal/fisiología , Factores de Crecimiento Endotelial/genética , Endotelio Vascular/embriología , Hipoxia , Linfocinas/genética , Proteínas Nucleares/genética , Factores de Transcripción , Animales , Anticuerpos Monoclonales , Biomarcadores , Vasos Sanguíneos/citología , Encéfalo/citología , Bucladesina/farmacología , Diferenciación Celular , Hipoxia de la Célula/fisiología , Proteínas de Unión al ADN/análisis , Factores de Crecimiento Endotelial/análisis , Endotelio Vascular/citología , Regulación del Desarrollo de la Expresión Génica , Factor 1 Inducible por Hipoxia , Subunidad alfa del Factor 1 Inducible por Hipoxia , Inmunohistoquímica , Linfocinas/análisis , Ratones , Ratones Endogámicos BALB C , Nitroimidazoles/análisis , Nitroimidazoles/inmunología , Proteínas Nucleares/análisis , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/análisis , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/genética , Células Madre/citología , Células Madre/efectos de los fármacos , Células Madre/fisiología , Teratoma , Células Tumorales Cultivadas , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Oxidative stress is thought to be a causative factor for age-related damage in a wide variety of cellular constituents that can lead to dysfunction and various pathological conditions, including the inflammatory process. At the molecular level, the redox-sensitive transcription factor, NF-κB plays a key role in the regulation of the inflammatory process, along with cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). We studied the mechanism underlying the modulation of the inflammatory reaction with age by investigating NF-κB activation and the expression of COX-2, iNOS, and cytokines genes in hepatic tissues isolated from young and old rats. We expanded our investigation of these factors in rats injected with the inflammatory activator, lipopolysaccharide (LPS). Data showed that NF-κB activity was up-regulated with age and was further enhanced by LPS injection, indicating an increased susceptibility and sensitivity to the inflammatory stimulus with age. To explore further the molecular events leading to NF-κB activation, we investigated the inhibitory component of NF-κB complex, IκB. Cytosolic IκBα, but not IκBß, was significantly decreased in both old and LPS-treated rats, signifying the enhanced migration of cytosolic NF-κB complex into the nucleus following dissociation from the inhibitor. The appearance of the polypeptide, p65, as determined in the nucleus, corresponded with the change in IκBα, providing further supporting evidence for the molecular process involved in NF-κB activation. Our additional investigation of two proinflammatory-related enzymes, COX-2 and iNOS, and three cytokines, interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-α, clearly showed aged-related increases, in corroboration with the NF-κB activation. Our results demonstrated that LPS injection caused the enhanced gene expression of inducible proinflammatory proteins, COX-2 and iNOS through NF-κB activation.
RESUMEN
It has been proposed that uric acid is an important scavenger of deleterious oxygen species and peroxynitrite in biological systems. The cellular sources responsible for the generation of damage-causing reactive oxygen species (ROS) are widespread. Xanthine dehydrogenase (XDH) / oxidase (XOD) catalyzes the oxidation of xanthine to uric acid. The rosy (ry) gene encodes XDH/XOD in Drosophila melanogaster. XDH codes for uric acid which is a ROS scavenger. XOD however is an enzyme system implicated in ROS production. In this study, we investigated the roles of XDH in the fly's immune defense response to infection and in the aging process. We first compared ROS generation and nitric oxide (NO) level in the whole body and the gut of XDH mutant with those of wild type. Our results suggested that XDH has a protective effect with respect to both ROS and NO generations, particularly in the gut. We also examined the effect of a XDH deletion mutant on the relative sensitivity of the organism against bacterial infection, on the immune inducibility of antimicrobial peptides and on the effect of aging in the defensive response to infection. Our results strongly suggest that XDH plays an important role in the innate immune response and that the age-associated deterioration of the innate immune response might be, at least in part, associated with the loss of XDH activity in the aging process.
RESUMEN
Ursolic acid (UA), a pentacyclic triterpene acid, has been reported to exhibit anti-tumor activity. In this study, we investigated the pro-apoptotic effect of UA on HepG2 human hepatoblastoma cells. Treatment with UA decreased the viability of HepG2 cells in a concentration- and time-dependent manner. Furthermore, 30 microM of UA induced DNA fragmentation and subdiploid cells and enhanced the release of cytochrome c and the activation of caspase-3. These results suggest that UA induces cell death through apoptosis, which may be mediated by cytochrome c-dependent caspase-3 activation. In addition, cell-cycle analysis revealed that UA-treated cells were arrested predominantly in the G(0) and G(1) phases with a concomitant decrease in the cell population of S phase. Moreover, expression of p21(WAF1), a cell-cycle regulator, was increased by UA, indicating that p21(WAF1) might mediate UA-induced cell-cycle arrest. However, UA markedly inhibited SV40 DNA replication in the initiation stage in vitro and significantly reduced the DNA cleaving of topoisomerase I and the ssDNA binding activity of replication protein A. These results indicate that the inhibition of DNA replication by UA may result from blockade of the establishment of the replication fork during initiation stage, consequently contributing to UA-induced cell-cycle arrest. Taken together, we suggest that UA-induced cell-cycle arrest may be mediated by inhibition of DNA replication and the increase of p21(WAF1) expression, which induces the release of cytochrome c and the activation of caspase-3, leading to apoptosis of HepG2 cells.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Replicación del ADN/efectos de los fármacos , ADN de Neoplasias/biosíntesis , Origen de Réplica/efectos de los fármacos , Triterpenos/farmacología , Caspasa 3 , Caspasas/metabolismo , Ciclo Celular/efectos de los fármacos , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/biosíntesis , Grupo Citocromo c/metabolismo , ADN-Topoisomerasas de Tipo I/metabolismo , ADN de Neoplasias/metabolismo , ADN de Cadena Simple/metabolismo , ADN Viral/biosíntesis , Proteínas de Unión al ADN/metabolismo , Activación Enzimática/efectos de los fármacos , Activadores de Enzimas/farmacología , Humanos , Proteína de Replicación A , Virus 40 de los Simios/efectos de los fármacos , Virus 40 de los Simios/genética , Virus 40 de los Simios/metabolismo , Inhibidores de Topoisomerasa I , Células Tumorales Cultivadas , Replicación Viral/efectos de los fármacos , Ácido UrsólicoRESUMEN
Previous results indicate that ursolic acid (UA), a pentacyclic triterpene acid, has strong cytotoxic activity and effectively induces growth arrest in a variety of systems. However, the molecular mechanisms underlying anti-tumorigenic or chemopreventive activities of UA are poorly understood. To further determine the mechanism of UA, we investigated the effects of UA on the growth of human prostate epithelial cells. Upon treatment with UA, a concentration-dependent inhibition of cell viability was observed and cells developed many of the hallmark features of apoptosis, including condensation of chromatin and DNA fragmentation. These apoptotic effects of UA were accompanied by proteolytic cleavage of specific target proteins such as PARP, beta-catenin and Rad51 proteins suggesting the possible involvement of caspases. Western blotting and in vitro assay demonstrated that processing/activation of at least four caspases (caspase-1, -3, -8 and -9) accompanies the generation of UA-mediating apoptotic cell death. In addition to activation of caspases, the down-regulation of c-IAPs family proteins, which suppress the apoptotic death signaling by the direct inhibition of activated caspases, was also observed. However, UA did not affect both the level of p53 expression and the alteration of the balance between Bcl-2 and Bax expression. These data suggest that apoptotic signals evoked by UA treatment may converge caspases activation through down-regulation of c-IAPs family and without mitochondrial dysfunction.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Caspasas/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Genes de Partícula A Intracisternal/efectos de los fármacos , Próstata/citología , Transactivadores , Triterpenos/farmacología , Western Blotting , Células Cultivadas , Proteínas del Citoesqueleto/metabolismo , Fragmentación del ADN , Proteínas de Unión al ADN/metabolismo , Activación Enzimática/efectos de los fármacos , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Células Epiteliales/enzimología , Genes bcl-2 , Genes p53 , Humanos , Masculino , Mitocondrias/fisiología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteínas Proto-Oncogénicas/biosíntesis , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis , Recombinasa Rad51 , Proteína p53 Supresora de Tumor/biosíntesis , Proteína X Asociada a bcl-2 , beta Catenina , Ácido UrsólicoRESUMEN
The Drosophila raf (D-raf) gene promoter contains a recognition consensus sequence for Drosophila STAT (D-STAT). By band mobility shift assay, we detected a factor binding to the D-STAT-recognition sequence in extracts of cultured Drosophila cells treated with vanadate peroxide. UV-cross-linking analyses suggested the size of the binding factor to be almost same as that of D-STAT. Furthermore, the binding activity was increased in cells cotransfected with HOP and D-STAT expression plasmids. These results strongly suggest that D-STAT binds to the D-STAT recognition sequence in the D-raf gene promoter. Transient luciferase expression assay using Schneider 2 cells indicated that the D-raf gene promoter is activated by D-STAT through the D-STAT-binding site. Furthermore, analyses with transgenic flies carrying Draf-lacZ fusion genes with and without mutations in the D-STAT-binding site pointed to an important role in D-raf gene promoter activity throughout development. We also found that the D-STAT-binding site is required for injury-induced activation of the D-raf gene promoter. Here we propose that D-STAT can participate in regulation of the mitogen-activated protein kinase cascade through D-raf gene activation.
Asunto(s)
Drosophila/genética , Regulación del Desarrollo de la Expresión Génica , Proteínas Proto-Oncogénicas c-raf/metabolismo , Transcripción Genética , Animales , Animales Modificados Genéticamente , Células Cultivadas , Relación Dosis-Respuesta a Droga , Drosophila/inmunología , Proteínas de Drosophila , Femenino , Galactósidos/metabolismo , Regulación de la Expresión Génica , Peróxido de Hidrógeno/farmacología , Indoles/metabolismo , Quinasas Janus , Luciferasas/metabolismo , Sistema de Señalización de MAP Quinasas , Masculino , Modelos Genéticos , Plásmidos , Regiones Promotoras Genéticas , Unión Proteica , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-raf/genética , Secuencias Reguladoras de Ácidos Nucleicos , Factores de Tiempo , Factores de Transcripción , Activación Transcripcional , Transfección , Rayos Ultravioleta , Vanadatos/farmacología , beta-Galactosidasa/metabolismoRESUMEN
One of the potential causes of age-related neuronal damage can be reactive oxygen species (ROS), as the brain is particularly sensitive to oxidative damage. In the present study, we investigated the effects of aging and dietary restriction (DR) on ROS generation, lipid peroxidation, and antioxidant enzymes in cerebrum, hippocampus, and cerebellum of 6-, 12-, 18-, and 24-month-old rats. ROS generation significantly increased with age in cerebrum of ad libitum (AL) rats. However, no significant age-difference was observed in hippocampus and cerebellum. DR significantly decreased ROS generation in cerebrum and cerebellum at 24-months. On the other hand, the increased lipid peroxidation of AL rats during aging was significantly reduced by DR in all regions. Our results further showed that catalase activity decreased with age in cerebellum of AL rats, which was reversed by DR, although SOD activity had little change by aging and DR in all regions. In a similar way, glutathione (GSH) peroxidase activity increased with age in cerebrum of AL rats, while DR suppressed it at 24-months. These data further support the evidence that the vulnerability to oxidative stress in the brain is region-specific.
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Antioxidantes/metabolismo , Química Encefálica/fisiología , Dieta , Peroxidación de Lípido/fisiología , Especies Reactivas de Oxígeno/metabolismo , Envejecimiento/metabolismo , Animales , Encéfalo/enzimología , Catalasa/metabolismo , Cerebelo/enzimología , Cerebelo/metabolismo , Corteza Cerebral/enzimología , Corteza Cerebral/metabolismo , Hipocampo/enzimología , Hipocampo/metabolismo , Masculino , Ratas , Ratas Endogámicas F344 , Superóxido Dismutasa/metabolismo , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismoRESUMEN
Telomerase is an RNA-dependent DNA polymerase that maintains the tandem arrays of telomeric repeats at the eukaryotic chromosome ends. Because of its ability to replenish lost telomeric sequences, telomerase is thought to be required for cell proliferation. At present, very little information on the role of telomerase in aging is available. In the present study, we tested the telomerase activity of Fischer 344 rat testis and liver at 6, 12, 18 and 24 months of age. As the testis is an androgen-dependent tissue, we also investigated the changes of testosterone and mRNA levels of androgen receptor in this tissue. Our results show that the telomerase activity of Fischer 344 rat testis significantly reduced at 24 months of age compared to 6 months of age, and that the mRNA level of telomerase protein component 1 (TLP-1) show a corresponding decrease with the telomerase activity. Interestingly, this down-regulation was not observed in the liver. The testosterone level in testis increased until 18 months of age, but reduced by 50% at 24 months of age. Our conclusions are that the telomerase activity is age-dependent and its change is a tissue-specific phenomenon.
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Envejecimiento/metabolismo , Telomerasa/metabolismo , Envejecimiento/genética , Animales , Secuencia de Bases , Proteínas Portadoras/genética , Cartilla de ADN/genética , Regulación hacia Abajo , Hígado/metabolismo , Masculino , Proteínas de Unión a Fosfato , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas F344 , Receptores Androgénicos/genética , Testículo/metabolismo , Testosterona/metabolismoRESUMEN
The chronic myelogenous leukemic K562 cell line carrying Bcr-Abl tyrosine kinase is considered as pluripotent hematopoietic progenitor cells expressing markers for erythroid, granulocytic, monocytic, and megakaryocytic lineages. Here we investigated the signaling modulations required for induction of erythroid differentiation of K562 cells. When the K562 cells were treated with herbimycin A (an inhibitor of protein tyrosine kinase), ras antisense oligonucleotide, and PD98059 (a specific inhibitor of MEK), inhibition of ERK/MAPK activity and cell growth, and induction of erythroid differentiation were observed. The ras mutant, pZIPRas61leu-transfected cells, K562-Ras61leu, have shown a markedly decreased cell proliferation rate with approximately 2-fold doubling time, compared with the parental K562 cells, and about 60% of these cells have shown the phenotype of erythroid differentiation. In addition, herbimycin A inhibited the growth rate and increased the erythroid differentiation, but did not affect the elevated activity of ERK/MAPK in the K562-Ras61leu cells. On the other hand, effects of PD98059 on the growth and differentiation of K562-Ras61leu cells were biphasic. At low concentration of PD98059, which inhibited the elevated activity of ERK/MAPK to the level of parental cells, the growth rate increased and the erythroid differentiation decreased slightly, and at high concentration of PD98059, which inhibited the elevated activity of ERK/MAPK below that of the parental cells, the growth rate turned down and the erythroid differentiation was restored to the untreated control level. Taken together, these results suggest that an appropriate activity of ERK/MAPK is required to maintain the rapid growth and transformed phenotype of K562 cells.
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Células Precursoras Eritroides/fisiología , Eritropoyesis , Proteínas ras/metabolismo , Androstadienos/farmacología , Benzoquinonas , Proteínas Quinasas Dependientes de Calcio-Calmodulina , Diferenciación Celular/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Células Precursoras Eritroides/citología , Flavonoides/farmacología , Humanos , Células K562 , Lactamas Macrocíclicas , Leucemia Mieloide/patología , Oligonucleótidos Antisentido/farmacología , Quinonas/farmacología , Rifabutina/análogos & derivados , WortmaninaRESUMEN
In this study, the effects of the ursodeoxycholic acid (UDCA), and its derivatives, on DNA replication were examined using simian virus (SV40) DNA replication in vitro. We found that UDCA and its derivatives inhibited SV40 DNA replication, and predominantly inhibited the initiation stage of DNA replication. UDCA and its derivatives inhibited the DNA cleavage by topoisomerase I (topo I). Among them, HS-1183 significantly reduced the activity of topo I. UDCA, at 100 microM, significantly reduced polymerase alpha-primase (pol alpha-primase) activity, but HS-1030 and HS-1183 showed a weak inhibitory effect. The ssDNA binding activity of replication protein A (RPA) was little affected by UDCA and HS-1030, but was weakly inhibited by HS-1183. Based on their properties, we suggest that UDCA and its derivatives might inhibit some molecules that is required to establish replication forks during the initiation reaction and their cytotoxicity might be related to the inhibitory effect they have on this fundamental cellular process.
Asunto(s)
Antineoplásicos/farmacología , Replicación del ADN/efectos de los fármacos , Virus 40 de los Simios/efectos de los fármacos , Ácido Ursodesoxicólico/análogos & derivados , Ácido Ursodesoxicólico/farmacología , Replicación Viral/efectos de los fármacosRESUMEN
We have cloned and sequenced a cDNA encoding GTP-binding protein from a fish cell, CHSE-214. The clone was 1493 bp long and contained an open reading frame encoding 364 amino acids. It has the five sequence motifs G1-G5 that are conserved in all GTP-binding proteins. Its amino acid sequences are strikingly different from those of the well-characterized G-proteins. However, sequences closely related to this protein are found in various kinds of species including human, Arabidopsis, Drosophila and archaebacteria, suggesting a novel subfamily within the superfamily of the GTP-binding proteins. Northern analysis indicates that this gene is constitutively expressed at a low level in normal cells but is induced by fish rhabdovirus infection at about 24 h post infection and disappears thereafter. Based on these observations, we propose that this protein represents an evolutionarily conserved novel subfamily of GTP-binding proteins which may play an important role in fish rhabdovirus infection.
Asunto(s)
Enfermedades de los Peces/virología , Proteínas de Unión al GTP/genética , Infecciones por Rhabdoviridae/veterinaria , Salmón/genética , Secuencia de Aminoácidos , Animales , Clonación Molecular , Evolución Molecular , Proteínas de Unión al GTP/clasificación , Datos de Secuencia Molecular , Filogenia , Homología de Secuencia de AminoácidoRESUMEN
The DRE/DREF system plays an important role in transcription of DNA replication genes such as those encoding the 180 and 73 kDa subunits of DNA polymerase alpha as well as that for encoding PCNA. In this study, we found two sequences homologous to DRE (5'-TATCGATA-3') in the 5'-flanking region (-370 to -357 with respect to the transcription initiation site) of the D-raf gene and confirmed transcriptional activity through gel mobility shift assays, transient CAT assays, and spatial patterns of lacZ expression in transgenic larval tissues carrying D-raf and lacZ fusion genes. Further, we demonstrated that the D-raf gene is another target of the Zerknüllt (Zen) protein with observation of D-raf repression by Zen protein in cultured cells and its ectopic expression in the dorsal region of the homozygous zen mutant embryo. The evidence of DRE/DREF involvement in regulation of the D-raf gene obtained in this study strongly supports the idea that the DRE/DREF system is responsible for the coordinated regulation of cell proliferation-related genes in Drosophila.
Asunto(s)
Replicación del ADN , Proteínas de Drosophila , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/genética , Proto-Oncogenes , Factores de Transcripción/genética , Transcripción Genética , Animales , Cloranfenicol O-Acetiltransferasa/genética , Drosophila melanogaster , Proteínas de Homeodominio/farmacología , Regiones Promotoras Genéticas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-raf , Proteínas Represoras/farmacología , Transcripción Genética/efectos de los fármacosRESUMEN
A temperature-sensitive (ts) mutation of Drosophila melanogaster for D-raf, encoding a serine/threonine protein kinase, was newly induced by EMS-treatment. Temperature-shift experiments on the ts mutant revealed that D-raf is required during most of the developmental stages, and confirmed the previously reported roles of D-raf in the regulation of cell proliferation and in the determination of cell fates at terminal regions of the embryo (Nishida et al., EMBO J. 7:775-781, 1988; Ambrosio et al., Nature 342:288-291, 1989a). Detailed analysis of cell proliferation demonstrated the role of D-raf at other than M-phase in cell cycle. TSP analysis during pupal stages revealed yet another role of D-raf in eclosion. Mosaic analysis of an eclosion-defective hypomorphic mutation revealed the tissue responsible for this defect to be the muscle and/or nervous system in the thorax. Molecular lesion associated with the ts mutation was found to be an alteration of an amino acid residue in a highly conserved region that defines the kinase subdomain VIII. Molecular analysis of null mutations also suggested the importance of the kinase domain for the biological functions of D-raf. Elucidation of the multi-functional nature of signal transducers is of great importance for our understanding of the molecular mechanisms of development, and the ts mutation for pleiotropic D-raf obtained in this study promises to be useful for dissecting signal transduction pathways during development.
Asunto(s)
Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/genética , Genes de Insecto , Proto-Oncogenes , Animales , Ciclo Celular , División Celular , Drosophila melanogaster/embriología , Desarrollo Embrionario y Fetal/genética , Femenino , Masculino , Mutación , Transducción de Señal , TemperaturaRESUMEN
DNA polymerase beta (pol beta) cDNA of rat fused to an enhancer-promoter region plus a poly(A) signal sequence of actin 5C gene of Drosophila (abbreviated pol beta) was transferred to the Drosophila genome. Three of four constructed transgenic strains possessing transgene pol beta on different chromosomes were studied. Levels of the pol beta transcript and those of the polymerization activity of pol beta were markedly elevated in cultured cells transfected with pol beta-bearing vectors as well as in embryos of the transgenic strains. The popular idea that DNA polymerase beta participates in DNA repair was not supported by the observation that a pair of a normal and a pol beta strain, and the other pair of a mei-9 mei-41 (DNA-repair deficient double mutations) strain and a pol beta mei-9 mei-41 strain, showed no difference in survival within each pair after treatment with ultraviolet light, methylmethane sulfonate and mitomycin C. The other idea that DNA polymerase beta participates in recombination was supported by the findings that spontaneous frequency of recombination, either meiotic or mitotic, is significantly higher in a transgenic pol beta strain than in a non-transgenic strain. The enhanced recombination frequency in the pol beta strain may, however, reflect an indirect effect of over-produced pol beta proteins on chromosomal stability. Whatever the direct effect of rat pol beta is, the transgenic pol beta flies will be useful for study of the physiological role of pol beta and the mechanism of recombination.