RESUMEN

BACKGROUND: Previous evidence suggests sex differences in the clinical course of relapsing remitting multiple sclerosis (RRMS), but comprehensive early-stage prospective studies are lacking. We aim to quantify the impact of sex on clinical outcomes in early-stage RRMS. METHODS: Utilizing prospective cohort data, we assessed the impact of biological sex on time-to-relapse, disability progression (Expanded Disability Status Scale [EDSS]), extremity function (Nine-Hole Peg Test, Timed-25-food walk test), cognition (Paced Auditory Serial Addition Test, Symbol Digit Modalities Test), quality-of-life (Hamburg Quality of Life Questionnaire in Multiple Sclerosis, Short-Form-36), fatigue (Fatigue Severity Scale, Fatigue Scale for Motor and Cognitive functions), and depression (Beck Depression Inventory-II) in clinically isolated syndrome (CIS) or RRMS patients. Inclusion was within 12 months of symptom onset. Linear, negative binomial, mixed, and Cox models estimated male vs. female effects at the four-year follow-up including baseline-to-follow-up course. RESULTS: We included 149 patients (65.1 % female). Eighty-five completed four-year follow-up. No sex differences in time-to-relapse emerged (HR = 0.91;95 %CI = 0.53-1.58). Males had no increased risk of EDSS worsening (OR = 0.75;95 %CI = 0.21-2.35) compared to females. Similarly, minor/no sex differences emerged in other outcomes. CONCLUSIONS: Four years after first manifestation, neither disease activity (disability progression and relapse rate) nor patient-reported outcomes showed sex-related disparities in this early-MS-cohort. GOV IDENTIFIER: NCT01371071.

Asunto(s)

Progresión de la Enfermedad , Esclerosis Múltiple Recurrente-Remitente , Humanos , Masculino , Femenino , Adulto , Esclerosis Múltiple Recurrente-Remitente/fisiopatología , Estudios Prospectivos , Factores Sexuales , Calidad de Vida , Estudios de Seguimiento , Caracteres Sexuales , Depresión/etiología , Depresión/fisiopatología , Persona de Mediana Edad , Enfermedades Desmielinizantes/fisiopatología , Enfermedades Desmielinizantes/diagnóstico , Fatiga/etiología , Fatiga/fisiopatología

RESUMEN

BACKGROUND: Zinc pyrithione (ZPT) is the active ingredient most commonly used in many antidandruff treatments. Despite decades of successful use to treat human scalps, little is understood about the antifungal mechanism of action of ZPT. OBJECTIVES: The objective of this study is to understand the molecular mechanism by which ZPT inhibits fungal growth, the underlying basis for its therapeutic activity. METHODS: Modern systems biology approaches, such as deletion library screening and microarray analysis, were used in combination with traditional measures of metal content, microbial growth and enzyme assays. RESULTS: It was shown that ZPT inhibits fungal growth through increased cellular levels of copper, damaging iron-sulphur clusters of proteins essential for fungal metabolism. CONCLUSIONS: The molecular basis for the antifungal activity of the commonly used active ZPT has been elucidated, more than 50 years since its introduction, as utilizing a copper toxicity mechanism that targets critical iron-sulphur proteins.

Asunto(s)

Antifúngicos/farmacología , Malassezia/efectos de los fármacos , Micosis/tratamiento farmacológico , Compuestos Organometálicos/farmacología , Piridinas/farmacología , Cobre/metabolismo , Eliminación de Gen , Humanos , Malassezia/genética , Malassezia/metabolismo , Análisis por Micromatrices , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Dermatosis del Cuero Cabelludo/tratamiento farmacológico

RESUMEN

Salt concentration, vegetable juice powder (VJP) concentration and temperature were investigated to determine necessary conditions for incubation of curing brines including VJP and a starter culture containing Staphylococcus carnosus prior to production of naturally cured, no-nitrate/nitrite-added meat products. Subsequently, incubated brines were utilized to produce no-nitrate/nitrite-added sliced ham in which quality characteristics and residual nitrite concentrations were measured to determine feasibility of brine incubation for nitrate conversion prior to injection. Two ham treatments (one with VJP and starter culture; one with pre-converted VJP) and a nitrite-added control were used. No differences (P>0.05) were found for color in the VJP treatments. Control sliced ham was redder after 42 days of storage, retaining significantly (P<0.05) greater a* (redness) than either of the VJP treatments. Residual nitrite concentration was greater (P<0.05) in the control hams during the first week of storage. While the nitrite-added control retained greater red color and initially had more residual nitrite than the VJP treatments, the two VJP treatments did not differ from each other.

Asunto(s)

Comida Rápida/análisis , Manipulación de Alimentos/métodos , Conservación de Alimentos/métodos , Productos de la Carne/microbiología , Sales (Química)/química , Verduras/química , Animales , Microbiología de Alimentos , Concentración de Iones de Hidrógeno , Nitratos/análisis , Nitritos/análisis , Polvos , Staphylococcus/crecimiento & desarrollo , Temperatura , Sustancias Reactivas al Ácido Tiobarbitúrico/análisis

RESUMEN

Langerhans cell histiocytosis (LCH) is a neoplastic disorder that results in clonal proliferation of cells with a Langerhans cell (LC) phenotype. The pathogenesis of LCH is still poorly understood. In the present study, serial analysis of gene expression (SAGE) was applied to LCs generated from umbilical cord blood CD34+ progenitor cells to identify LC-specific genes and the expression of these genes in LCH was investigated. Besides the expression of several genes known to be highly expressed in LCs and LCH such as CD1a, LYZ, and CD207, high expression of genes not previously reported to be expressed in LCs, such as GSN, MMP12, CCL17, and CCL22, was also identified. Further analysis of these genes by quantitative RT-PCR revealed high expression of FSCN1 and GSN in all 12 LCH cases analysed; of CD207, MMP12, CCL22, and CD1a in the majority of these cases; and CCL17 in three of the 12 cases. Immunohistochemistry confirmed protein expression in the majority of cases. The expression of MMP12 was most abundant in multi-system LCH, which is the LCH type with the worst prognosis. This suggests that expression of MMP12 may play a role in the progression of LCH. These data reveal new insight into the pathology of LCH and provide new starting points for further investigation of this clonal proliferative disorder.

Asunto(s)

Perfilación de la Expresión Génica , Histiocitosis de Células de Langerhans/metabolismo , Células de Langerhans/química , Análisis de Secuencia por Matrices de Oligonucleótidos , Antígenos CD/análisis , Antígenos CD/genética , Antígenos CD1/análisis , Antígenos CD1/genética , Biomarcadores/análisis , Proteínas Portadoras/análisis , Proteínas Portadoras/genética , Quimiocina CCL17 , Quimiocina CCL22 , Quimiocinas CC/análisis , Quimiocinas CC/genética , Gelsolina/análisis , Gelsolina/genética , Expresión Génica , Biblioteca de Genes , Humanos , Inmunohistoquímica/métodos , Inmunofenotipificación , Lectinas Tipo C/análisis , Lectinas Tipo C/genética , Lectinas de Unión a Manosa/análisis , Lectinas de Unión a Manosa/genética , Metaloproteinasa 12 de la Matriz , Metaloendopeptidasas/análisis , Metaloendopeptidasas/genética , Proteínas de Microfilamentos/análisis , Proteínas de Microfilamentos/genética , Muramidasa/análisis , Muramidasa/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa

RESUMEN

AIM: To gain more insight into the genes involved in the aetiology and pathogenesis of anaplastic large cell lymphoma (ALCL). METHODS: Serial analysis of gene expression (SAGE) was undertaken on the CD4+ALK+ (anaplastic lymphoma kinase positive) ALCL derived cell line Karpas299 and as comparison on CD4+ T cells. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were performed on five ALCL derived cell lines and 32 tissue samples to confirm the SAGE data. RESULTS: High expression of Mcl-1 was seen in the Karpas299 cell line, whereas the two other antiapoptotic Bcl-2 family members, Bcl-2 and Bcl-X(L), were not detected in the SAGE library. Quantitative RT-PCR confirmed the high expression of Mcl-1 mRNA and low expression of Bcl-2 and Bcl-X(L) in Karpas299 and in four other ALCL cell lines. To expand on these initial observations, primary tissue samples were analysed for Mcl-1, Bcl-X(L), and Bcl-2 by immunohistochemistry. All 23 ALK+ and nine ALK- ALCL cases were positive for Mcl-1. Bcl-2 and Bcl-X(L) were expressed infrequently in ALK+ ALCL cases, but were present in a higher proportion of ALK- ALCL cases. CONCLUSION: The consistent high expression of Mcl-1 in ALK+ and ALK- ALCL suggests that Mcl-1 is the main antiapoptotic protein in this disease. The high frequency of Mcl-1, Bcl-2, and Bcl-X(L) positive ALCL cases in the ALK- group compared with the ALK+ group indicates that ALK induced STAT3 activation is not the main regulatory pathway in ALCL.

Asunto(s)

Regulación Neoplásica de la Expresión Génica/genética , Linfoma de Células B Grandes Difuso/genética , Proteínas de Neoplasias/genética , Proteínas Tirosina Quinasas/genética , Proteínas Proto-Oncogénicas c-bcl-2/genética , Quinasa de Linfoma Anaplásico , Apoptosis/genética , Linfocitos T CD4-Positivos/fisiología , Línea Celular Tumoral , Genes bcl-2/genética , Humanos , Inmunohistoquímica/métodos , Proteína 1 de la Secuencia de Leucemia de Células Mieloides , ARN Mensajero/genética , ARN Neoplásico/genética , Proteínas Tirosina Quinasas Receptoras , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Proteína bcl-X

RESUMEN

Poliovirus (PV) replicates its genome in association with membranous vesicles in the cytoplasm of infected cells. To elucidate the origin and mode of formation of PV vesicles, immunofluorescence labeling with antibodies against the viral vesicle marker proteins 2B and 2BC, as well as cellular markers of the endoplasmic reticulum (ER), anterograde transport vesicles, and the Golgi complex, was performed in BT7-H cells. Optical sections obtained by confocal laser scanning microscopy were subjected to a deconvolution process to enhance resolution and signal-to-noise ratio and to allow for a three-dimensional representation of labeled membrane structures. The mode of formation of the PV vesicles was, on morphological grounds, similar to the formation of anterograde membrane traffic vesicles in uninfected cells. ER-resident membrane markers were excluded from both types of vesicles, and the COPII components Sec13 and Sec31 were both found to be colocalized on the vesicular surface, indicating the presence of a functional COPII coat. PV vesicle formation during early time points of infection did not involve the Golgi complex. The expression of PV protein 2BC or the entire P2 and P3 genomic region led to the production of vesicles carrying a COPII coat and showing the same mode of formation as vesicles produced after PV infection. These results indicate that PV vesicles are formed at the ER by the cellular COPII budding mechanism and thus are homologous to the vesicles of the anterograde membrane transport pathway.

Asunto(s)

Vesículas Cubiertas por Proteínas de Revestimiento/ultraestructura , Proteínas Portadoras/fisiología , Fosfoproteínas/fisiología , Poliovirus/fisiología , Proteínas de Saccharomyces cerevisiae , Replicación Viral , Animales , Vesículas Cubiertas por Proteínas de Revestimiento/virología , Proteínas Portadoras/metabolismo , Proteínas Portadoras/ultraestructura , Membrana Celular/virología , Células Cultivadas , Retículo Endoplásmico/virología , Haplorrinos , Microscopía Confocal , Fosfoproteínas/ultraestructura , Poliovirus/ultraestructura , Proteínas de Transporte Vesicular , Proteínas no Estructurales Virales/metabolismo

RESUMEN

Transplantation of dopamine-secreting cells harvested from fetal mesencephalon directly into the striatum has had limited success as a therapy for Parkinson's disease. A major problem is that the majority of the cells die during the first 3 weeks following transplantation. Hypoxia in the tissue surrounding the graft is a potential cause of the cell death. We have used subtractive cDNA libraries and microarray analysis to identify the gene expression profile that regulates tolerance to hypoxia. An improved understanding of the molecular basis of hypoxia-tolerance may allow investigators to engineer cells that can survive in the hypoxic environment of the brain parenchyma following transplantation.

RESUMEN

Akt is a serine/threonine kinase that has been shown to play a central role in promoting cell survival and opposing apoptosis. We evaluated the effect of hypoxia on Akt in rat pheochromocytoma (PC12) cells. PC12 cells were exposed to varying levels of hypoxia, including 21%, 15%, 10%, 5%, and 1% O(2). Hypoxia dramatically increased phosphorylation of Akt (Ser(473)). This effect peaked after 6 h exposure to hypoxia, but persisted strongly for up to 24 h. Phosphorylation of Akt was paralleled with a progressive increase in phosphorylation of glycogen synthase kinase-3 (GSK-3), one of its downstream substrates. The effect of hypoxia on phosphorylation of Akt was completely blocked by pretreatment of the cells with wortmannin (100 nM), indicating that this effect is mediated by phosphatidylinositol 3-kinase (P13K). In contrast, whereas hypoxia also strongly induced phosphorylation of the transcription factors CREB and EPAS1, these effects persisted in the presence of wortmannin. Thus, hypoxia regulates both P13K-dependent and P13K-independent signaling pathways. Furthermore, activation of the P13K and Akt signaling pathways may be one mechanism by which cells adapt and survive under conditions of hypoxia.

Asunto(s)

Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Hipoxia de la Célula/fisiología , Fosfotransferasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Androstadienos/metabolismo , Androstadienos/farmacología , Animales , Glucógeno Sintasa Quinasa 3 , Glucógeno Sintasa Quinasas , Células PC12 , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Isoformas de Proteínas , Proteínas Proto-Oncogénicas c-akt , Ratas , Transducción de Señal/fisiología , Especificidad por Sustrato , Factores de Transcripción/efectos de los fármacos , Factores de Transcripción/metabolismo , Wortmanina

RESUMEN

Hypoxia is a common environmental stimulus. However, very little is known about the mechanisms by which cells sense and respond to changes in oxygen. Our laboratory has utilized the PC12 cell line in order to study the biophysical and molecular response to hypoxia. The current review summarizes our results. We demonstrate that the O2-sensitive K(+) channel, Kv1.2, is present in PC12 cells and plays a critical role in the hypoxia-induced depolarization of PC12 cells. Previous studies have shown that PC12 cells secrete a variety of autocrine/paracrine factors, including dopamine, norepinephrine, and adenosine during hypoxia. We investigated the mechanisms by which adenosine modulates cell function and the effect of chronic hypoxia on this modulation. Finally, we present results identifying the mitogen- and stress-activated protein kinases (MAPKs and SAPKs) as hypoxia-regulated protein kinases. Specifically, we show that p38 and an isoform, p38gamma, are activated by hypoxia. In addition, our results demonstrate that the p42/p44 MAPK protein kinases are activated by hypoxia. We further show that p42/p44 MAPK is critical for the hypoxia-induced transactivation of endothelial PAS-domain protein 1 (EPAS1), a hypoxia-inducible transcription factor. Together, these results provide greater insight into the mechanisms by which cells sense and adapt to hypoxia.

Asunto(s)

Hipoxia , Oxígeno/metabolismo , Feocromocitoma/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Electroforesis en Gel de Poliacrilamida , Electrofisiología , Activación Enzimática , Sistema de Señalización de MAP Quinasas , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Células PC12 , Canales de Potasio/metabolismo , Isoformas de Proteínas , Ratas , Factores de Tiempo , Transactivadores/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos

RESUMEN

Aeromonas hydrophila, an opportunist human pathogen of low virulence, was shown to display a high degree of sensitivity upon exposure to hydrogen peroxide. As with other species, Aer. hydrophila is able to develop the capacity to resist loss of viability induced by such oxidative stress. Development of stress resistance follows the archetypal profile where pre-exposure of a population to sub-lethal levels of H2O2 stimulates onset of tolerance to further exposure. Acquisition of tolerance critically requires nascent protein synthesis. Further analysis demonstrated population growth phase influences the degree of sensitivity of the organism. Late stationary phase cultures demonstrate a decreased sensitivity compared with younger populations. Significantly, it was also determined that stock culture age influenced the level of sensitivity of the derived experimental culture, where an increased stock culture age corresponded with enhanced resistance to H2O2. These data show that Aer. hydrophila population phenotype is influenced by the phenotype of the donor stock culture.

Asunto(s)

Aeromonas hydrophila/efectos de los fármacos , Aeromonas hydrophila/metabolismo , Peróxido de Hidrógeno/farmacología , Estrés Oxidativo , Adaptación Fisiológica , Aeromonas hydrophila/crecimiento & desarrollo , Proteínas Bacterianas/biosíntesis , Recuento de Colonia Microbiana , Biosíntesis de Péptidos , Factores de Tiempo

RESUMEN

Multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM) are conditions whose closely related pathology suggests shared pathophysiological elements, but whose clinical courses are usually, but not always quite dissimilar. The former is largely a disease of adulthood, the latter of childhood. Optic neuritis, demyelinative transverse myelitis, and Devic's syndrome are neurological syndromes that may occur as manifestations of either MS or ADEM. Patients with Miller-Fisher syndrome and encephalomyelradiculoneuropathy usually have features suggesting ADEM in combination with acute demyelinative polyneuropathy. These various conditions and other forms of ADEM share an indistinct border with encephalitides, granulomatous, and vasculitic conditions. MS, ADEM, and the pertinent syndromic subtypes, their differential diagnosis, treatment, and prognosis are considered in this review. Acute cerebellar ataxia is a syndrome that is likely to be pathophysiologically distinct from ADEM, although its occurrence as a postinfectious illness suggests a distant kinship. It is also reviewed.

Asunto(s)

Encéfalo/patología , Encéfalo/fisiopatología , Ataxia Cerebelosa/diagnóstico , Encefalomielitis Aguda Diseminada/diagnóstico , Encefalomielitis Aguda Diseminada/fisiopatología , Leucoencefalitis Hemorrágica Aguda/diagnóstico , Esclerosis Múltiple/diagnóstico , Esclerosis Múltiple/fisiopatología , Mielitis Transversa/diagnóstico , Neuromielitis Óptica/diagnóstico , Neuritis Óptica/diagnóstico , Enfermedad Aguda , Ataxia Cerebelosa/terapia , Diagnóstico Diferencial , Encefalomielitis Aguda Diseminada/terapia , Humanos , Leucoencefalitis Hemorrágica Aguda/terapia , Esclerosis Múltiple/terapia , Mielitis Transversa/terapia , Neuromielitis Óptica/terapia , Neuritis Óptica/terapia , Pronóstico

Asunto(s)

Hipoxia de la Célula/genética , Hipoxia de la Célula/fisiología , Animales , Calcio/metabolismo , Citosol/metabolismo , Retroalimentación , Regulación de la Expresión Génica , Homeostasis , Potenciales de la Membrana , Modelos Biológicos , Oxígeno/metabolismo , Células PC12 , Ratas , Transcripción Genética , Tirosina 3-Monooxigenasa/genética

RESUMEN

The mechanisms by which excitable cells adapt and respond to changes in O2 levels remain largely unknown. We have investigated the effect of hypoxia on the cyclic AMP response element binding protein (CREB) transcription factor. PC12 cells were exposed to moderate levels of hypoxia (5% O2) for various times between 20 min and 6 hr. We found that hypoxia rapidly and persistently induced ser133 phosphorylation of CREB. This effect was more robust than that produced by exposing PC12 cells to either forskolin, KCl, or NGF. This effect was not due to activation of any of the previously known CREB kinases, including PKA, CaMK, PKC, p70s6k, or MAPKAP kinase-2. Thus, hypoxia may induce activation of a novel CREB kinase. To test whether phosphorylation of CREB was associated with an activation of CRE-dependent gene expression, cells were transfected with wild type and mutated regions of the 5'-flanking region of the tyrosine hydroxylase (TH) gene fused to a CAT reporter gene. Mutation of the CRE element in a TH reporter gene reduced, but did not abolish, the effects of hypoxia on TH gene expression. However, hypoxia did not induce transactivation of a GAL4-luciferase reporter by a GAL4-CREB fusion protein. Thus, the mechanism by which hypoxia regulates CREB is distinct, and more complex, than that induced by forskolin, depolarization, or nerve growth factor.

Asunto(s)

Hipoxia de la Célula/fisiología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Proteínas de Saccharomyces cerevisiae , Animales , Fusión Artificial Génica , Hipoxia de la Célula/genética , Cloranfenicol O-Acetiltransferasa/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/química , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteínas de Unión al ADN , Activación Enzimática , Proteínas Fúngicas/genética , Expresión Génica , Genes Reporteros , Luciferasas/genética , Modelos Biológicos , Células PC12 , Fosforilación , Ratas , Proteínas Quinasas S6 Ribosómicas/metabolismo , Serina/metabolismo , Transducción de Señal , Factores de Transcripción/genética , Transfección , Tirosina 3-Monooxigenasa/genética

Asunto(s)

Neuropatías del Plexo Braquial/rehabilitación , Parálisis Obstétrica/rehabilitación , Modalidades de Fisioterapia/métodos , Rango del Movimiento Articular , Neuropatías del Plexo Braquial/fisiopatología , Moldes Quirúrgicos , Niño , Terapia por Estimulación Eléctrica , Humanos , Debilidad Muscular/rehabilitación , Terapia Ocupacional , Parálisis Obstétrica/fisiopatología , Enfermedades del Sistema Nervioso Periférico/rehabilitación , Férulas (Fijadores)

RESUMEN

Pork by-products (lung lobes, kidneys), chicken viscera (head, feet and viscera) and mechanically separated chicken (MSC) were evaluated for proximate composition, protein distribution and connective tissue. Proximate composition varied among meat by-products and MSC. Pork by-products contained the most crude protein (p<0.05). Low levels of high ionic strength soluble (HIS) proteins were obtained from meat by-products. Pork lungs and chicken viscera contained the greatest amounts of insoluble (IN) proteins (p<0.05). Total collagen values were positively correlated to IN proteins, intramuscular collagen (IMC) and elastin. Types I and III collagen could not be detected by SDS-PAGE for the different meat by-products though collagen solubility appeared to be significant. These results suggest functional property differences between specific by-products are likely when used in petfood product formulations.

RESUMEN

Contributions to water retention capacity (% WRC) and texture changes were determined for pork by-products (lung lobes, kidneys), chicken viscera (head, feet and viscera) and mechanically separated chicken (MSC) as affected by pH and various salts in a high-moisture model system. The % WRC for meat by-products and MSC was increased by increased pH (4.5-6.8). Pork lungs and MSC had the highest % WRC (p<0.05) among the meat by-products. Meat by-product % WRC was not signifcantly (p>0.05) affected by salt (2%), phosphate (0.3%) or NaOH (0.075%). Chicken viscera had the lowest (p<0.05) mean texture measurements among the meat by-products and MSC. Strong negative correlations (p<0.05) were obtained for texture with total collagen, soluble collagen and high ionic strength soluble (HIS) proteins. These results should be considered for product quality changes when these by-products are used in formulation of high moisture pet food products.

RESUMEN

Hypoxic/ischemic trauma is a primary factor in the pathology of a multitude of disease states. The effects of hypoxia on the stress- and mitogen-activated protein kinase signaling pathways were studied in PC12 cells. Exposure to moderate hypoxia (5% O(2)) progressively stimulated phosphorylation and activation of p38gamma in particular, and also p38alpha, two stress-activated protein kinases. In contrast, hypoxia had no effect on enzyme activity of p38beta, p38beta(2), p38delta, or on c-Jun N-terminal kinase, another stress-activated protein kinase. Prolonged hypoxia also induced phosphorylation and activation of p42/p44 mitogen-activated protein kinase, although this activation was modest compared with nerve growth factor- and ultraviolet light-induced activation. Hypoxia also dramatically down-regulated immunoreactivity of cyclin D1, a gene that is known to be regulated negatively by p38 at the level of gene expression (Lavoie, J. N., L'Allemain, G., Brunet, A., Muller, R., and Pouyssegur, J. (1996) J. Biol. Chem. 271, 20608-20616). This effect was partially blocked by SB203580, an inhibitor of p38alpha but not p38gamma. Overexpression of a kinase-inactive form of p38gamma was also able to reverse in part the effect of hypoxia on cyclin D1 levels, suggesting that p38alpha and p38gamma converge to regulate cyclin D1 during hypoxia. These studies demonstrate that an extremely typical physiological stress (hypoxia) causes selective activation of specific p38 signaling elements; and they also identify a downstream target of these pathways.

Asunto(s)

Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Hipoxia de la Célula , Isoenzimas/metabolismo , Proteínas Quinasas Activadas por Mitógenos , Animales , Ciclina D1/metabolismo , Activación Enzimática , Células PC12 , Fosforilación , Ratas , Factores de Transcripción/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos

RESUMEN

Most eukaryotic initiation factors (eIFs) are required for internal translation initiation at the internal ribosome entry site (IRES) of picornaviruses. eIF4B is incorporated into ribosomal 48S initiation complexes with the IRES RNA of foot-and-mouth disease virus (FMDV). In contrast to the weak interaction of eIF4B with capped cellular mRNAs and its release upon entry of the ribosomal 60S subunit, eIF4B remains tightly associated with the FMDV IRES during formation of complete 80S ribosomes. Binding of eIF4B to the IRES is energy dependent, and binding of the small ribosomal subunit to the IRES requires the previous energy-dependent association of initiation factors with the IRES. The interaction of eIF4B with the IRES in 48S and 80S complexes is independent of the location of the initiator AUG and thus independent of the mechanism by which the small ribosomal subunit is placed at the actual start codon, either by direct internal ribosomal entry or by scanning. eIF4B does not greatly rearrange its binding to the IRES upon entry of the ribosomal subunits, and the interaction of eIF4B with the IRES is independent of the polypyrimidine tract-binding protein, which enhances FMDV translation.

Asunto(s)

Aphthovirus/genética , Codón Iniciador , Factores Eucarióticos de Iniciación , Factores de Iniciación de Péptidos/metabolismo , Biosíntesis de Proteínas , ARN Viral , Proteínas Ribosómicas/metabolismo , Ribosomas/metabolismo , Animales , Sitios de Unión , Cinética , Proteína de Unión al Tracto de Polipirimidina , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/metabolismo

RESUMEN

Eukaryotic translation initiation factor 4B (eIF4B) binds directly to the internal ribosome entry site (IRES) of foot-and-mouth disease virus (FMDV). Mutations in all three subdomains of the IRES stem-loop 4 reduce binding of eIF4B and translation efficiency in parallel, indicating that eIF4B is functionally involved in FMDV translation initiation. In reticulocyte lysate devoid of polypyrimidine tract-binding protein (PTB), eIF4B still bound well to the wild-type IRES, even after removal of the major PTB-binding site. In conclusion, the interaction of eIF4B with the FMDV IRES is essential for IRES function but independent of PTB.

Asunto(s)

Aphthovirus/metabolismo , Factores Eucarióticos de Iniciación , Factores de Iniciación de Péptidos/metabolismo , Biosíntesis de Proteínas , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/metabolismo , Ribosomas/metabolismo , Aphthovirus/genética , Secuencia de Bases , Células Eucariotas , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Iniciación de la Cadena Peptídica Traduccional , Proteína de Unión al Tracto de Polipirimidina , ARN Viral

RESUMEN

The California serogroup viruses are mosquito viruses that cause human infections on five continents. They are maintained and amplified in nature by a wide variety of mosquito vectors and mammalian hosts; they thrive in a remarkably wide variety of microclimates (eg, tropical, coastal temperate marshland, lowland river valleys, alpine valleys and highlands, high boreal deserts, and arctic steppes). In 1993, California serogroup viruses caused 71% of all cases of arboviral illness in the United States, principally La Crosse encephalitis. The 30 to 180 annual cases of La Crosse encephalitis represent 8% to 30% of all cases of encephalitis, rendering this illness the most common and important endemic mosquito-borne illness in the USA. Subclinical or mild infections are much more common. Methods and results acquired from intense study of California serogroup viruses have been applied, with benefit, to the study of the ecology and pathogenesis of many more serious human arboviral illnesses. The evolutionary potential of viruses, with particular reference to the development of more virulent strains, has been studied more closely in the California serogroup viruses than in almost any other agent of human disease.

Asunto(s)

Infecciones por Bunyaviridae , Encefalitis de California/virología , Animales , Antivirales/uso terapéutico , Infecciones por Bunyaviridae/tratamiento farmacológico , Infecciones por Bunyaviridae/epidemiología , California/epidemiología , Culicidae , Vectores de Enfermedades , Encefalitis de California/tratamiento farmacológico , Encefalitis de California/epidemiología , Humanos , Ribavirina/uso terapéutico