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1.
Cell ; 159(3): 530-42, 2014 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-25417105

RESUMEN

Aggregation of damaged or misfolded proteins is a protective mechanism against proteotoxic stress, abnormalities of which underlie many aging-related diseases. Here, we show that in asymmetrically dividing yeast cells, aggregation of cytosolic misfolded proteins does not occur spontaneously but requires new polypeptide synthesis and is restricted to the surface of ER, which harbors the majority of active translation sites. Protein aggregates formed on ER are frequently also associated with or are later captured by mitochondria, greatly constraining aggregate mobility. During mitosis, aggregates are tethered to well-anchored maternal mitochondria, whereas mitochondria acquired by the bud are largely free of aggregates. Disruption of aggregate-mitochondria association resulted in increased mobility and leakage of mother-accumulated aggregates into the bud. Cells with advanced replicative age exhibit gradual decline of aggregates-mitochondria association, likely contributing to their diminished ability to rejuvenate through asymmetric cell division.


Asunto(s)
Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/fisiología , División Celular , Citosol/metabolismo , Retículo Endoplásmico/metabolismo , Mitocondrias/metabolismo , Agregado de Proteínas , Biosíntesis de Proteínas , Saccharomyces cerevisiae/crecimiento & desarrollo , Estrés Fisiológico
2.
Genes Dev ; 26(23): 2604-20, 2012 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-23166019

RESUMEN

Monomethylation of histone H3 on Lys 4 (H3K4me1) and acetylation of histone H3 on Lys 27 (H3K27ac) are histone modifications that are highly enriched over the body of actively transcribed genes and on enhancers. Although in yeast all H3K4 methylation patterns, including H3K4me1, are implemented by Set1/COMPASS (complex of proteins associated with Set1), there are three classes of COMPASS-like complexes in Drosophila that could carry out H3K4me1 on enhancers: dSet1, Trithorax, and Trithorax-related (Trr). Here, we report that Trr, the Drosophila homolog of the mammalian Mll3/4 COMPASS-like complexes, can function as a major H3K4 monomethyltransferase on enhancers in vivo. Loss of Trr results in a global decrease of H3K4me1 and H3K27ac levels in various tissues. Assays with the cut wing margin enhancer implied a functional role for Trr in enhancer-mediated processes. A genome-wide analysis demonstrated that Trr is required to maintain the H3K4me1 and H3K27ac chromatin signature that resembles the histone modification patterns described for enhancers. Furthermore, studies in the mammalian system suggested a role for the Trr homolog Mll3 in similar processes. Since Trr and mammalian Mll3/4 complexes are distinguished by bearing a unique subunit, the H3K27 demethylase UTX, we propose a model in which the H3K4 monomethyltransferases Trr/Mll3/Mll4 and the H3K27 demethylase UTX cooperate to regulate the transition from inactive/poised to active enhancers.


Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimología , Drosophila melanogaster/genética , Elementos de Facilitación Genéticos , N-Metiltransferasa de Histona-Lisina/metabolismo , Histonas/metabolismo , Animales , Línea Celular , Proteínas de Drosophila/genética , Estudio de Asociación del Genoma Completo , N-Metiltransferasa de Histona-Lisina/genética , Metilación
3.
J Biol Chem ; 290(12): 7871-86, 2015 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-25623066

RESUMEN

Although endogenous mechanisms that negatively regulate cytochrome P450 (P450) monooxygenases in response to physiological and pathophysiological signals are not well understood, they are thought to result from alterations in the level of endogenous metabolites, involved in maintaining homeostasis. Here we show that homeostatic changes in hepatic metabolite profile in Abcb6 (mitochondrial ATP-binding cassette transporter B6) deficiency results in suppression of a specific subset of hepatic P450 activity. Abcb6 null mice are more susceptible to pentobarbital-induced sleep and zoxazolamine-induced paralysis, secondary to decreased expression and activity of Cyp3a11 and Cyp2b10. The knock-out mice also show decrease in both basal and xeno-inducible expression and activity of a subset of hepatic P450s that appear to be related to changes in hepatic metabolite profile. These data, together with the observation that liver extracts from Abcb6-deficient mice suppress P450 expression in human primary hepatocytes, suggest that this mouse model may provide an opportunity to understand the physiological signals and the mechanisms involved in negative regulation of P450s.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Hígado/metabolismo , Animales , Secuencia de Bases , Cartilla de ADN , Hígado/enzimología , Espectrometría de Masas , Ratones
4.
Sci Rep ; 10(1): 3488, 2020 02 26.
Artículo en Inglés | MEDLINE | ID: mdl-32103097

RESUMEN

A critical global health need exists for a Zika vaccine capable of mitigating the effects of future Zika epidemics. In this study we evaluated the antibody responses and efficacy of an aluminum hydroxide adjuvanted purified inactivated Zika vaccine (PIZV) against challenge with Zika virus (ZIKV) strain PRVABC59. Indian rhesus macaques received two doses of PIZV at varying concentrations ranging from 0.016 µg - 10 µg and were subsequently challenged with ZIKV six weeks or one year following the second immunization. PIZV induced a dose-dependent immune response that was boosted by a second immunization. Complete protection against ZIKV infection was achieved with the higher PIZV doses of 0.4 µg, 2 µg, and 10 µg at 6 weeks and  with 10 ug PIZV at  1 year following vaccination. Partial protection was achieved with the lower PIZV doses of 0.016 µg and 0.08 µg. Based on these data, a neutralizing antibody response above 3.02 log10 EC50 was determined as a correlate of protection in macaques. PIZV elicited a dose-dependent neutralizing antibody response which is protective for at least 1 year following vaccination.


Asunto(s)
Vacunas de Productos Inactivados , Vacunas Virales , Infección por el Virus Zika , Virus Zika , Animales , Femenino , Masculino , Anticuerpos Neutralizantes/sangre , Modelos Animales de Enfermedad , Inmunoglobulina G/sangre , Macaca , ARN Viral/inmunología , ARN Viral/metabolismo , Vacunación , Vacunas de Productos Inactivados/inmunología , Vacunas Virales/inmunología , Virus Zika/inmunología , Virus Zika/patogenicidad , Infección por el Virus Zika/patología , Infección por el Virus Zika/prevención & control
5.
Oxid Med Cell Longev ; 2017: 9251303, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28163822

RESUMEN

Arsenite is a known carcinogen and its exposure has been implicated in a variety of noncarcinogenic health concerns. Increased oxidative stress is thought to be the primary cause of arsenite toxicity and the toxic effect is thought to be linear with detrimental effects reported at all concentrations of arsenite. But the paradigm of linear dose response in arsenite toxicity is shifting. In the present study we demonstrate that arsenite effects on mitochondrial respiration in primary hepatocytes follow a nonlinear dose response. In vitro exposure of primary hepatocytes to an environmentally relevant, moderate level of arsenite results in increased oxidant production that appears to arise from changes in the expression and activity of respiratory Complex I of the mitochondrial proton circuit. In primary hepatocytes the excess oxidant production appears to elicit adaptive responses that promote resistance to oxidative stress and a propensity to increased proliferation. Taken together, these results suggest a nonlinear dose-response characteristic of arsenite with low-dose arsenite promoting adaptive responses in a process known as mitohormesis, with transient increase in ROS levels acting as transducers of arsenite-induced mitohormesis.


Asunto(s)
Arsenitos/farmacología , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Animales , Arsenitos/toxicidad , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Relación Dosis-Respuesta a Droga , Metabolismo Energético , Células Hep G2 , Humanos , Ratones , Consumo de Oxígeno/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo
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