RESUMEN
Synucleinopathies are a group of neurodegenerative diseases without effective treatment characterized by the abnormal aggregation of alpha-synuclein (aSyn) protein. Changes in levels or in the amino acid sequence of aSyn (by duplication/triplication of the aSyn gene or point mutations in the encoding region) cause familial cases of synucleinopathies. However, the specific molecular mechanisms of aSyn-dependent toxicity remain unclear. Increased aSyn protein levels or pathological mutations may favor abnormal protein-protein interactions (PPIs) that could either promote neuronal death or belong to a coping response program against neurotoxicity. Therefore, the identification and modulation of aSyn-dependent PPIs can provide new therapeutic targets for these diseases. To identify aSyn-dependent PPIs we performed a proximity biotinylation assay based on the promiscuous biotinylase BioID2. When expressed as a fusion protein, BioID2 biotinylates by proximity stable and transient interacting partners, allowing their identification by streptavidin affinity purification and mass spectrometry. The aSyn interactome was analyzed using BioID2-tagged wild-type (WT) and pathological mutant E46K aSyn versions in HEK293 cells. We found the 14-3-3 epsilon isoform as a common protein interactor for WT and E46K aSyn. 14-3-3 epsilon correlates with aSyn protein levels in brain regions of a transgenic mouse model overexpressing WT human aSyn. Using a neuronal model in which aSyn cell-autonomous toxicity is quantitatively scored by longitudinal survival analysis, we found that stabilization of 14-3-3 protein-proteins interactions with Fusicoccin-A (FC-A) decreases aSyn-dependent toxicity. Furthermore, FC-A treatment protects dopaminergic neuronal somas in the substantia nigra of a Parkinson's disease mouse model. Based on these results, we propose that the stabilization of 14-3-3 epsilon interaction with aSyn might reduce aSyn toxicity, and highlight FC-A as a potential therapeutic compound for synucleinopathies.
Asunto(s)
Sinucleinopatías , alfa-Sinucleína , Ratones , Humanos , Animales , alfa-Sinucleína/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Células HEK293 , Ratones Transgénicos , Neuronas Dopaminérgicas/metabolismoRESUMEN
In amyotrophic lateral sclerosis (ALS) patients, loss of cellular homeostasis within cortical and spinal cord motor neurons triggers the activation of the integrated stress response (ISR), an intracellular signaling pathway that remodels translation and promotes a gene expression program aimed at coping with stress. Beyond its neuroprotective role, under regimes of chronic or excessive stress, ISR can also promote cell/neuronal death. Given the two-edged sword nature of ISR, many experimental attempts have tried to establish the therapeutic potential of ISR enhancement or inhibition in ALS. This review discusses the complex interplay between ISR and disease progression in different models of ALS, as well as the opportunities and limitations of ISR modulation in the hard quest to find an effective therapy for ALS.
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Esclerosis Amiotrófica Lateral , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/terapia , Muerte Celular , Progresión de la Enfermedad , Humanos , Neuronas Motoras/metabolismoRESUMEN
Coronavirus disease 2019 can cause significant mortality in the elderly in long-term care facilities (LTCF). We describe 4 LTCF outbreaks where mass testing identified a high proportion of asymptomatic infections (4%-41% in healthcare workers and 20%-75% in residents), indicating that symptom-based screening alone is insufficient for monitoring for COVID-19 transmission.
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COVID-19 , Anciano , Brotes de Enfermedades , Humanos , Cuidados a Largo Plazo , SARS-CoV-2 , San Francisco , Instituciones de Cuidados Especializados de EnfermeríaRESUMEN
CONTEXT: In March, 2020, the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causal agent of coronavirus disease 2019 (COVID-19), was spreading in the Bay Area, especially in Santa Clara County, causing increases in cases, hospitalizations, and deaths. PROGRAM: The Association of Bay Area Health Officials (ABAHO) represents 13 Bay Area health jurisdictions. IMPLEMENTATION: On March 15, 2020, the local health officers of 7 ABAHO members (counties of Alameda, Contra Costa, Marin, San Francisco, San Mateo, and Santa Clara and the city of Berkeley) decided to issue legal orders on March 16 for 6.7 million residents to shelter in place to prevent the spread of SARS-CoV-2, the causal agent of COVID-19. The Bay Area was the first region in the United States to shelter in place, and within days, other regions in the United States followed. EVALUATION: Subsequent comparative analyses have confirmed that acting early in issuing shelter-in-place orders prevented a large number of cases, hospitalizations, and deaths in the Bay Area throughout the United States. The quality of a decision-in this case, for crisis decision making-cannot be judged by the outcome. A good decision can have a bad outcome, and a bad decision can have a good outcome. The quality of a decision depends only on the quality of the decision-making process at the time the decision was made. DISCUSSION: In this Field Report, we review how we made this collective decision. With the benefit of hindsight and reflection, we recount our story through the lens of public health legal authority, meta-leadership, and decision intelligence. Our purpose is to improve the crisis decision-making skills of public health officials by improving how we make high-stakes decisions each day in our continuing fight to contain the SARS-CoV-2 pandemic, to save lives, and to eliminate COVID-19 racial/ethnic inequities.
Asunto(s)
COVID-19/prevención & control , Guías como Asunto , Pandemias/legislación & jurisprudencia , Pandemias/prevención & control , Política , Salud Pública/legislación & jurisprudencia , Salud Pública/normas , Adulto , Anciano , Anciano de 80 o más Años , California/epidemiología , Toma de Decisiones , Femenino , Humanos , Liderazgo , Masculino , Persona de Mediana Edad , New York/epidemiología , Pandemias/estadística & datos numéricos , SARS-CoV-2 , Estados Unidos/epidemiologíaRESUMEN
Alpha-synuclein (aSyn) protein levels are sufficient to drive Parkinson's disease (PD) and other synucleinopathies. Despite the biomedical/therapeutic potential of aSyn protein regulation, little is known about mechanisms that limit/control aSyn levels. Here, we investigate the role of a post-translational modification, N-terminal acetylation, in aSyn neurotoxicity. N-terminal acetylation occurs in all aSyn molecules and has been proposed to determine its lipid binding and aggregation capacities; however, its effect in aSyn stability/neurotoxicity has not been evaluated. We generated N-terminal mutants that alter or block physiological aSyn N-terminal acetylation in wild-type or pathological mutant E46K aSyn versions and confirmed N-terminal acetylation status by mass spectrometry. By optical pulse-labeling in living primary neurons we documented a reduced half-life and accumulation of aSyn N-terminal mutants. To analyze the effect of N-terminal acetylation mutants in neuronal toxicity we took advantage of a neuronal model where aSyn toxicity was scored by longitudinal survival analysis. Salient features of aSyn neurotoxicity were previously investigated with this approach. aSyn-dependent neuronal death was recapitulated either by higher aSyn protein levels in the case of WT aSyn, or by the combined effect of protein levels and enhanced neurotoxicity conveyed by the E46K mutation. aSyn N-terminal mutations decreased E46K aSyn-dependent neuronal death both by reducing protein levels and, importantly, by reducing the intrinsic E46K aSyn toxicity, being the D2P mutant the least toxic. Together, our results illustrate that the N-terminus determines, most likely through its acetylation, aSyn protein levels and toxicity, identifying this modification as a potential therapeutic target.
Asunto(s)
Neuronas/metabolismo , Enfermedad de Parkinson/genética , Agregación Patológica de Proteínas/metabolismo , alfa-Sinucleína/metabolismo , Acetilación , Muerte Celular/genética , Humanos , Mutación/genética , Enfermedad de Parkinson/metabolismo , Agregación Patológica de Proteínas/genética , Procesamiento Proteico-Postraduccional/genética , Estabilidad ProteicaRESUMEN
The current SARS-CoV-2 pandemic is wreaking havoc throughout the world and has rapidly become a global health emergency. A central question concerning COVID-19 is why some individuals become sick and others not. Many have pointed already at variation in risk factors between individuals. However, the variable outcome of SARS-CoV-2 infections may, at least in part, be due also to differences between the viral subspecies with which individuals are infected. A more pertinent question is how we are to overcome the current pandemic. A vaccine against SARS-CoV-2 would offer significant relief, although vaccine developers have warned that design, testing and production of vaccines may take a year if not longer. Vaccines are based on a handful of different designs (i), but the earliest vaccines were based on the live, attenuated virus. As has been the case for other viruses during earlier pandemics, SARS-CoV-2 will mutate and may naturally attenuate over time (ii). What makes the current pandemic unique is that, thanks to state-of-the-art nucleic acid sequencing technologies, we can follow in detail how SARS-CoV-2 evolves while it spreads. We argue that knowledge of naturally emerging attenuated SARS-CoV-2 variants across the globe should be of key interest in our fight against the pandemic.
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Betacoronavirus , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , COVID-19 , Infecciones por Coronavirus , Brotes de Enfermedades , Humanos , Pandemias , Neumonía Viral , SARS-CoV-2RESUMEN
BACKGROUND & AIMS: Polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of multiple biliary cysts. Recently, novel PLD-causative genes, encoding for endoplasmic reticulum (ER)-resident proteins involved in protein biogenesis and transport, were identified. We hypothesized that aberrant proteostasis contributes to PLD pathogenesis, representing a potential therapeutic target. METHODS: ER stress was analysed at transcriptional (qPCR), proteomic (mass spectrometry), morphological (transmission electron microscopy, TEM) and functional (proteasome activity) levels in different PLD models. The effect of ER stress inhibitors [4-phenylbutyric acid (4-PBA)] and/or activators [tunicamycin (TM)] was tested in polycystic (PCK) rats and cystic cholangiocytes in vitro. RESULTS: The expression levels of unfolded protein response (UPR) components were upregulated in liver tissue from PLD patients and PCK rats, as well as in primary cultures of human and rat cystic cholangiocytes, compared to normal controls. Cystic cholangiocytes showed altered proteomic profiles, mainly related to proteostasis (ie synthesis, folding, trafficking and degradation of proteins), marked enlargement of the ER lumen (by TEM) and hyperactivation of the proteasome. Notably, chronic treatment of PCK rats with 4-PBA decreased liver weight, as well as both liver and cystic volumes, of animals under baseline conditions or after TM administration compared to controls. In vitro, 4-PBA downregulated the expression (mRNA) of UPR effectors, normalized proteomic profiles related to protein synthesis, folding, trafficking and degradation and reduced the proteasome hyperactivity in cystic cholangiocytes, reducing their hyperproliferation and apoptosis. CONCLUSIONS: Restoration of proteostasis in cystic cholangiocytes with 4-PBA halts hepatic cystogenesis, emerging as a novel therapeutic strategy.
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Quistes , Hepatopatías , Animales , Conductos Biliares , Proliferación Celular , Quistes/tratamiento farmacológico , Modelos Animales de Enfermedad , Estrés del Retículo Endoplásmico , Humanos , Hepatopatías/tratamiento farmacológico , Hepatopatías/metabolismo , Proteómica , Proteostasis , RatasRESUMEN
The unfolded protein response (UPR) allows cells to adjust secretory pathway capacity according to need. Ire1, the endoplasmic reticulum (ER) stress sensor and central activator of the UPR is conserved from the budding yeast Saccharomyces cerevisiae to humans. Under ER stress conditions, Ire1 clusters into foci that enable optimal UPR activation. To discover factors that affect Ire1 clustering, we performed a high-content screen using a whole-genome yeast mutant library expressing Ire1-mCherry. We imaged the strains following UPR induction and found 154 strains that displayed alterations in Ire1 clustering. The hits were enriched for iron and heme effectors and binding proteins. By performing pharmacological depletion and repletion, we confirmed that iron (Fe3+) affects UPR activation in both yeast and human cells. We suggest that Ire1 clustering propensity depends on membrane composition, which is governed by heme-dependent biosynthesis of sterols. Our findings highlight the diverse cellular functions that feed into the UPR and emphasize the cross-talk between organelles required to concertedly maintain homeostasis.
Asunto(s)
Estrés del Retículo Endoplásmico/fisiología , Hierro/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Transducción de Señal/fisiología , Respuesta de Proteína Desplegada/fisiología , Glicoproteínas de Membrana/genética , Proteínas Serina-Treonina Quinasas/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genéticaRESUMEN
BACKGROUND & AIMS: Liver regeneration after partial hepatectomy (PH) increases the protein folding burden at the endoplasmic reticulum of remnant hepatocytes, resulting in induction of the unfolded protein response. We investigated the role of the core unfolded protein response transcription factor X-box binding protein 1 (XBP1) in liver regeneration using genome-wide chromatin immunoprecipitation analysis. METHODS: We performed studies with C57Bl6-J (control) and interleukin 6-knockout mice. Mice underwent PH or sham surgeries. In some mice, hepatic expression of XBP1 was knocked down by injection of adenoviral vectors encoding small hairpin RNAs against Xbp1 messenger RNA. Liver tissues were collected before surgery and at 6 and 48 hours after surgery and analyzed by chromatin immunoprecipitation followed by sequencing. We also performed functional analyses of HepG2 cells. RESULTS: Expression of XBP1 by hepatocytes increased immediately after PH (priming phase of liver regeneration) in control mice, but this effect was delayed in interleukin 6-deficient mice. In mice with knockdown of XBP1, we observed of liver tissue persistent endoplasmic reticulum stress, defects in acute-phase response, and increased hepatocellular damage, compared with control mice. Chromatin immunoprecipitation analyses of liver tissue showed that at 6 hours after PH, liver XBP1 became bound to a large set of genes implicated in proteostasis, the acute-phase response, metabolism, and the DNA damage response (DDR). At this time point, XBP1 bound the promoter of the signal transducer and activator of transcription 3 gene (Stat3). Livers of XBP1-knockdown mice showed reduced expression of STAT3 and had lower levels of STAT3 phosphorylation at Ser727, a modification that promotes cell proliferation and the DDR. Regenerating livers from XBP1-knockdown mice expressed high levels of a marker of DNA double-strand breaks, phosphorylated histone 2A, member X (H2AX), compared with control mice. The inhibition of XBP1 expression caused a reduced up-regulation of DDR messenger RNAs in regenerating hepatocytes. CONCLUSION: In livers of mice, we found that PH induces expression of XBP1, and that this activity requires interleukin 6. XBP1 expression regulates the unfolded protein response, acute-phase response, and DDR in hepatocytes. In regenerating livers, XBP1 deficiency leads to endoplasmic reticulum stress and DNA damage.
Asunto(s)
Reacción de Fase Aguda/genética , Daño del ADN/genética , Estrés del Retículo Endoplásmico/genética , Regeneración Hepática/genética , Hígado/metabolismo , Respuesta de Proteína Desplegada/genética , Proteína 1 de Unión a la X-Box/genética , Animales , Células Hep G2 , Hepatectomía , Humanos , Interleucina-6/genética , Ratones , Ratones Noqueados , Fosforilación , Factor de Transcripción STAT3/metabolismoRESUMEN
BACKGROUND: The San Francisco Health Improvement Partnership (SFHIP) promotes health equity by using a novel collective impact model that blends community engagement with evidence-to-policy translational science. The model involves diverse stakeholders, including ethnic-based community health equity coalitions, the local public health department, hospitals and health systems, a health sciences university, a school district, the faith community, and others sectors. COMMUNITY CONTEXT: We report on 3 SFHIP prevention initiatives: reducing consumption of sugar sweetened beverages (SSBs), regulating retail alcohol sales, and eliminating disparities in children's oral health. METHODS: SFHIP is governed by a steering committee. Partnership working groups for each initiative collaborate to 1) develop and implement action plans emphasizing feasible, scalable, translational-science-informed interventions and 2) consider sustainability early in the planning process by including policy and structural interventions. OUTCOME: Through SFHIP's efforts, San Francisco enacted ordinances regulating sale and advertising of SSBs and a ballot measure establishing a soda tax. Most San Francisco hospitals implemented or committed to implementing healthy-beverage policies that prohibited serving or selling SSBs. SFHIP helped prevent Starbucks and Taco Bell from receiving alcohol licenses in San Francisco and helped prevent state authorization of sale of powdered alcohol. SFHIP increased the number of primary care clinics providing fluoride varnish at routine well-child visits from 3 to 14 and acquired a state waiver to allow dental clinics to be paid for dental services delivered in schools. INTERPRETATION: The SFHIP model of collective impact emphasizing community engagement and policy change accomplished many of its intermediate goals to create an environment promoting health and health equity.
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Política de Salud , Bebidas/estadística & datos numéricos , Participación de la Comunidad , Ingestión de Energía , Equidad en Salud , Política de Salud/economía , Política de Salud/legislación & jurisprudencia , Humanos , Inositol/análogos & derivados , Programas Nacionales de Salud , Encuestas Nutricionales , Salud Bucal , San Francisco , Instituciones AcadémicasAsunto(s)
Presupuestos/tendencias , Planificación en Desastres/tendencias , Financiación Gubernamental/tendencias , Pandemias/prevención & control , Planificación en Desastres/economía , Humanos , Pandemias/economía , Salud Pública/tendencias , Estados Unidos , United States Dept. of Health and Human ServicesRESUMEN
CONTEXT: Extreme weather events, unpredictable and often far-reaching, constitute a persistent challenge for public health preparedness. OBJECTIVE: The goal of this research is to inform public health systems improvement through examination of extreme weather events, comparing across cases to identify recurring patterns in event and response characteristics. DESIGN: Structured telephone-based interviews were conducted with representatives from health departments to assess characteristics of recent extreme weather events and agencies' responses. Response activities were assessed using the Centers for Disease Control and Prevention Public Health Emergency Preparedness Capabilities framework. Challenges that are typical of this response environment are reported. SETTING: Forty-five local health departments in 20 US states. RESULTS: Respondents described public health system responses to 45 events involving tornadoes, flooding, wildfires, winter weather, hurricanes, and other storms. Events of similar scale were infrequent for a majority (62%) of the communities involved; disruption to critical infrastructure was universal. Public Health Emergency Preparedness Capabilities considered most essential involved environmental health investigations, mass care and sheltering, surveillance and epidemiology, information sharing, and public information and warning. Unanticipated response activities or operational constraints were common. CONCLUSIONS: We characterize extreme weather events as a "quadruple threat" because (1) direct threats to population health are accompanied by damage to public health protective and community infrastructure, (2) event characteristics often impose novel and pervasive burdens on communities, (3) responses rely on critical infrastructures whose failure both creates new burdens and diminishes response capacity, and (4) their infrequency and scale further compromise response capacity. Given the challenges associated with extreme weather events, we suggest opportunities for organizational learning and preparedness improvements.
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Planificación en Desastres , Salud Pública , Tiempo (Meteorología) , Humanos , Entrevistas como Asunto , Investigación Cualitativa , Estados UnidosRESUMEN
Acute intermittent porphyria (AIP) is a hepatic metabolic disease that results from haplo-insufficient activity of porphobilinogen deaminase (PBGD). The dominant clinical feature is acute intermittent attacks when hepatic heme synthesis is activated by endocrine or exogenous factors. Gene therapy vectors over-expressing PBGD protein in the liver offers potential as a cure for AIP. Here, we developed a helper-dependent adenovirus (HDA) encoding human PBGD (hPBGD) and assessed its therapeutic efficacy in a murine model of AIP. Intravenous or intrahepatic administration of HDA-hPBGD to AIP mice resulted in a sustained hepatic hPBGD expression in a dose-dependent manner. Intrahepatic administration conveyed full protection against induced porphyria attacks at a significantly lower viral dose than intravenous injection. Transgenic hPBGD accumulated only in the cytosol of hepatocytes as the endogenous protein. Characterization of PBGD-deficient mouse strains revealed that a strong PBGD deficiency causes the chronic disturbance of cytosolic and endoplasmic reticulum folding machineries. This disturbance was completely restored over time by the over-expression of hPBGD. HDA-hPBGD is a promising vector that protects against porphyria attacks and resolves the chronic folding stress associated with low levels of PBGD activity.
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Adenoviridae/genética , Terapia Genética , Hidroximetilbilano Sintasa/genética , Porfiria Intermitente Aguda/genética , Porfiria Intermitente Aguda/terapia , Adenoviridae/fisiología , Animales , Modelos Animales de Enfermedad , Femenino , Vectores Genéticos/genética , Vectores Genéticos/fisiología , Hepatocitos/enzimología , Hepatocitos/virología , Humanos , Hidroximetilbilano Sintasa/metabolismo , Hígado/enzimología , Hígado/virología , Masculino , Ratones , Ratones Endogámicos C57BL , Porfiria Intermitente Aguda/enzimología , Porfiria Intermitente Aguda/prevención & control , Pliegue de ProteínaRESUMEN
Deficiencies in the protein-folding capacity of the endoplasmic reticulum (ER) in all eukaryotic cells lead to ER stress and trigger the unfolded protein response (UPR). ER stress is sensed by Ire1, a transmembrane kinase/endoribonuclease, which initiates the non-conventional splicing of the messenger RNA encoding a key transcription activator, Hac1 in yeast or XBP1 in metazoans. In the absence of ER stress, ribosomes are stalled on unspliced HAC1 mRNA. The translational control is imposed by a base-pairing interaction between the HAC1 intron and the HAC1 5' untranslated region. After excision of the intron, transfer RNA ligase joins the severed exons, lifting the translational block and allowing synthesis of Hac1 from the spliced HAC1 mRNA to ensue. Hac1 in turn drives the UPR gene expression program comprising 7-8% of the yeast genome to counteract ER stress. Here we show that, on activation, Ire1 molecules cluster in the ER membrane into discrete foci of higher-order oligomers, to which unspliced HAC1 mRNA is recruited by means of a conserved bipartite targeting element contained in the 3' untranslated region. Disruption of either Ire1 clustering or HAC1 mRNA recruitment impairs UPR signalling. The HAC1 3' untranslated region element is sufficient to target other mRNAs to Ire1 foci, as long as their translation is repressed. Translational repression afforded by the intron fulfils this requirement for HAC1 mRNA. Recruitment of mRNA to signalling centres provides a new paradigm for the control of eukaryotic gene expression.
Asunto(s)
Retículo Endoplásmico/metabolismo , ARN de Hongos/metabolismo , ARN Mensajero/metabolismo , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/genética , Transducción de Señal , Estrés Fisiológico , Regiones no Traducidas 3'/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Secuencia Conservada , Regulación Fúngica de la Expresión Génica/genética , Intrones/genética , Glicoproteínas de Membrana/metabolismo , Biosíntesis de Proteínas , Proteínas Serina-Treonina Quinasas/metabolismo , Empalme del ARN , ARN de Hongos/genética , ARN Mensajero/genética , Proteínas Represoras/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Estrés Fisiológico/genéticaRESUMEN
BACKGROUND & AIMS: Cardiotrophin-1 (CT-1) is a hepatoprotective cytokine that modulates fat and glucose metabolism in muscle and adipose tissue. Here we analyzed the changes in hepatic fat stores induced by recombinant CT-1 (rCT-1) and its therapeutic potential in non-alcoholic fatty liver disease (NAFLD). METHODS: rCT-1 was administered to two murine NAFLD models: ob/ob and high fat diet-fed mice. Livers were analyzed for lipid composition and expression of genes involved in fat metabolism. We studied the effects of rCT-1 on lipogenesis and fatty acid (FA) oxidation in liver cells and the ability of dominant negative inhibitor of AMP-activated protein kinase (AMPK) to block these effects. RESULTS: CT-1 was found to be upregulated in human and murine steatotic livers. In two NAFLD mouse models, treatment with rCT-1 for 10days induced a marked decrease in liver triglyceride content with augmented proportion of poly-unsaturated FA and reduction of monounsaturated species. These changes were accompanied by attenuation of inflammation and improved insulin signaling. Chronic administration of rCT-1 caused downregulation of lipogenic genes and genes involved in FA import to hepatocytes together with amelioration of ER stress, elevation of NAD(+)/NADH ratio, phosphorylation of LKB1 and AMPK, increased expression and activity of sirtuin1 (SIRT1) and upregulation of genes mediating FA oxidation. rCT-1 potently inhibited de novo lipogenesis and stimulated FA oxidation in liver cells both in vitro and in vivo. In vitro studies showed that these effects are mediated by activated AMPK. CONCLUSIONS: rCT-1 resolves hepatic steatosis in obese mice by mechanisms involving AMPK activation. rCT-1 deserves consideration as a potential therapy for NAFLD.
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Proteínas Quinasas Activadas por AMP/metabolismo , Citocinas/metabolismo , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Animales , Citocinas/genética , Citocinas/uso terapéutico , Dieta Alta en Grasa/efectos adversos , Modelos Animales de Enfermedad , Activación Enzimática , Ácidos Grasos/metabolismo , Hepatocitos/metabolismo , Humanos , Resistencia a la Insulina , Metabolismo de los Lípidos , Lipogénesis , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/uso terapéutico , Sirtuina 1/metabolismo , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Factores de Transcripción/metabolismo , Regulación hacia ArribaRESUMEN
BACKGROUND AND PURPOSE: The integrated stress response (ISR) regulates translation in response to diverse stresses. ISR activation has been documented in amyotrophic lateral sclerosis (ALS) patients and ALS experimental models. In experimental models, both ISR stimulation and inhibition prevented ALS neurodegeneration; however, which mode of ISR regulation would work in patients is still debated. We previously demonstrated that the ISR modulator ISRIB (Integrated Stress Response InhiBitor, an eIF2B activator) enhances survival of neurons expressing the ALS neurotoxic allele SOD1 G93A. Here, we tested the effect of two ISRIB-like eIF2B activators (2BAct and PRXS571) in the disease progression of transgenic SOD1G93A mice. EXPERIMENTAL APPROACH: After biochemical characterization in primary neurons, SOD1G93A mice were treated with 2BAct and PRXS571. Muscle denervation of vulnerable motor units was monitored with a longitudinal electromyographic test. We used a clinical score to document disease onset and progression; force loss was determined with the hanging wire motor test. Motor neuronal survival was assessed by immunohistochemistry. KEY RESULTS: In primary neurons, 2BAct and PRXS571 relieve the ISR-imposed translational inhibition while maintaining high ATF4 levels. Electromyographic recordings evidenced an earlier and more dramatic muscle denervation in treated SOD1G93A mice that correlated with a decrease in motor neuron survival. Both compounds anticipated disease onset and shortened survival time. CONCLUSION AND IMPLICATIONS: 2BAct and PRXS571 anticipate disease onset, aggravating muscle denervation and motor neuronal death of SOD1G93A mice. This study reveals that the ISR works as a neuroprotective pathway in ALS motor neurons and reveals the toxicity that eIF2B activators may display in ALS patients.
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Esclerosis Amiotrófica Lateral , Humanos , Ratones , Animales , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/metabolismo , Superóxido Dismutasa-1/genética , Factor 2B Eucariótico de Iniciación , Superóxido Dismutasa/metabolismo , Ratones Transgénicos , Progresión de la Enfermedad , Modelos Animales de EnfermedadRESUMEN
The unfolded protein response (UPR) is an intracellular signaling pathway that counteracts variable stresses that impair protein folding in the endoplasmic reticulum (ER). As such, the UPR is thought to be a homeostat that finely tunes ER protein folding capacity and ER abundance according to need. The mechanism by which the ER stress sensor Ire1 is activated by unfolded proteins and the role that the ER chaperone protein BiP plays in Ire1 regulation have remained unclear. Here we show that the UPR matches its output to the magnitude of the stress by regulating the duration of Ire1 signaling. BiP binding to Ire1 serves to desensitize Ire1 to low levels of stress and promotes its deactivation when favorable folding conditions are restored to the ER. We propose that, mechanistically, BiP achieves these functions by sequestering inactive Ire1 molecules, thereby providing a barrier to oligomerization and activation, and a stabilizing interaction that facilitates de-oligomerization and deactivation. Thus BiP binding to or release from Ire1 is not instrumental for switching the UPR on and off as previously posed. By contrast, BiP provides a buffer for inactive Ire1 molecules that ensures an appropriate response to restore protein folding homeostasis to the ER by modulating the sensitivity and dynamics of Ire1 activity.
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Retículo Endoplásmico/patología , Proteínas Fúngicas/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Homeostasis , Glicoproteínas de Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimología , Estrés Fisiológico , Respuesta de Proteína Desplegada , Biología Computacional , Simulación por Computador , Retículo Endoplásmico/enzimología , Activación Enzimática , Transferencia Resonante de Energía de Fluorescencia , Cinética , Glicoproteínas de Membrana/química , Modelos Biológicos , Unión Proteica , Proteínas Serina-Treonina Quinasas/química , Estructura Cuaternaria de Proteína , Reproducibilidad de los Resultados , Proteínas de Saccharomyces cerevisiae/química , Factores de TiempoRESUMEN
BACKGROUND: Public health surveillance and epidemiologic investigations are critical public health functions for identifying threats to the health of a community. Very little is known about how these functions are conducted at the local level. The purpose of the Epidemiology Networks in Action (EpiNet) Study was to describe the epidemiology and surveillance response to the 2009 pandemic influenza A (H1N1) by city and county health departments in the San Francisco Bay Area in California. The study also documented lessons learned from the response in order to strengthen future public health preparedness and response planning efforts in the region. METHODS: In order to characterize the epidemiology and surveillance response, we conducted key informant interviews with public health professionals from twelve local health departments in the San Francisco Bay Area. In order to contextualize aspects of organizational response and performance, we recruited two types of key informants: public health professionals who were involved with the epidemiology and surveillance response for each jurisdiction, as well as the health officer or his/her designee responsible for H1N1 response activities. Information about the organization, data sources for situation awareness, decision-making, and issues related to surge capacity, continuity of operations, and sustainability were collected during the key informant interviews. Content and interpretive analyses were conducted using ATLAS.ti software. RESULTS: The study found that disease investigations were important in the first months of the pandemic, often requiring additional staff support and sometimes forcing other public health activities to be put on hold. We also found that while the Incident Command System (ICS) was used by all participating agencies to manage the response, the manner in which it was implemented and utilized varied. Each local health department (LHD) in the study collected epidemiologic data from a variety of sources, but only case reports (including hospitalized and fatal cases) and laboratory testing data were used by all organizations. While almost every LHD attempted to collect school absenteeism data, many respondents reported problems in collecting and analyzing these data. Laboratory capacity to test influenza specimens often aided an LHD's ability to conduct disease investigations and implement control measures, but the ability to test specimens varied across the region and even well-equipped laboratories exceeded their capacity. As a whole, the health jurisdictions in the region communicated regularly about key decision-making (continued on next page) (continued from previous page) related to the response, and prior regional collaboration on pandemic influenza planning helped to prepare the region for the novel H1N1 influenza pandemic. The study did find, however, that many respondents (including the majority of epidemiologists interviewed) desired an increase in regional communication about epidemiology and surveillance issues. CONCLUSION: The study collected information about the epidemiology and surveillance response among LHDs in the San Francisco Bay Area that has implications for public health preparedness and emergency response training, public health best practices, regional public health collaboration, and a perceived need for information sharing.
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Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Gobierno Local , Vigilancia de la Población/métodos , Administración en Salud Pública , Planificación en Salud Comunitaria/métodos , Relaciones Comunidad-Institución , Humanos , Entrevistas como Asunto , Notificación Obligatoria , Pandemias , Salud Pública , Regionalización , San Francisco/epidemiología , Servicios de Salud Escolar , Vigilancia de GuardiaRESUMEN
BACKGROUND: The large-scale deployment of antiviral drugs from the Strategic National Stockpile during the 2009 H1N1 influenza response provides a unique opportunity to study local public health implementation of the medical countermeasure dispensing capability in a prolonged event of national significance. This study aims to describe the range of methods used by local health departments (LHDs) in California to manage antiviral activities and to gain a better understanding of the related challenges experienced by health departments and their community partners. METHODS: This research employed a mixed-methods approach. First, a multi-disciplinary focus group of pandemic influenza planners from key stakeholder groups in California was convened in order to generate ideas and identify critical themes related to the local implementation of antiviral activities during the H1N1 influenza response. These qualitative data informed the development of a web-based survey, which was distributed to all 61 LHDs in California for the purpose of assessing the experiences of a representative sample of local health agencies in a large region. RESULTS: Forty-four LHDs participated in this study, representing 72% of the local public health agencies in California. While most communities dispensed a modest number of publicly purchased antivirals, LHDs nevertheless drew on their previous work and engaged in a number of antiviral activities, including: acquiring, allocating, distributing, dispensing, tracking, developing guidance, and communicating to the public and clinical community. LHDs also identified specific antiviral challenges presented by the H1N1 pandemic, including: reconciling multiple sources and versions of antiviral guidance, determining appropriate uses and recipients of publicly purchased antivirals, and staffing shortages. CONCLUSIONS: The 2009 H1N1 influenza pandemic presented an unusual opportunity to learn about the role of local public health in the management of antiviral response activities during a real public health emergency. Results of this study offer an important descriptive account of LHD management of publicly purchased antivirals, and provide practitioners, policy makers, and academics with a practice-based assessment of these events. The issues raised and the challenges faced by LHDs should be leveraged to inform public health planning for future pandemics and other emergency events that require medical countermeasure dispensing activities.
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Antivirales/provisión & distribución , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/prevención & control , Gobierno Local , Administración en Salud Pública , Adulto , Antivirales/economía , Antivirales/uso terapéutico , California/epidemiología , Toma de Decisiones en la Organización , Brotes de Enfermedades/prevención & control , Costos de los Medicamentos/estadística & datos numéricos , Grupos Focales , Encuestas de Atención de la Salud , Fuerza Laboral en Salud , Humanos , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Humana/tratamiento farmacológico , Gripe Humana/epidemiología , Guías de Práctica Clínica como AsuntoRESUMEN
BACKGROUND: Due to the uncommon nature of large-scale disasters and emergencies, public health practitioners often turn to simulated emergencies, known as "exercises", for preparedness assessment and improvement. Under the right conditions, exercises can also be used to conduct original public health systems research. This paper describes the integration of a research framework into a statewide operations-based exercise program in California as a systems-based approach for studying public health emergency preparedness and response. METHODS: We developed a research framework based on the premise that operations-based exercises conducted by medical and public health agencies can be described using epidemiologic concepts. Using this framework, we conducted a survey of key local and regional medical and health agencies throughout California following the 2010 Statewide Medical and Health Exercise. The survey evaluated: (1) the emergency preparedness capabilities activated and functions performed in response to the emergency scenario, and (2) the major challenges to inter-organizational communications and information management. RESULTS: Thirty-five local health departments (LHDs), 24 local emergency medical services (EMS) agencies, 121 hospitals, and 5 Regional Disaster Medical and Health Coordinators/Specialists (RDMHC) responded to our survey, representing 57%, 77%, 26% and 83%, respectively, of target agencies in California. We found two sets of response capabilities were activated during the 2010 Statewide Exercise: a set of core capabilities that were common across all agencies, and a set of agency-specific capabilities that were more common among certain agency types. With respect to one response capability in particular, inter-organizational information sharing, we found that the majority of respondents' comments were related to the complete or partial failure of communications equipment or systems. CONCLUSIONS: Using the 2010 Statewide Exercise in California as an opportunity to develop our research framework, we characterized several aspects of the public health and medical system's response to a standardized emergency scenario. From a research perspective, this study provides a potential new framework for conducting exercise-based research. From a practitioner's perspective, our results provide a starting point for preparedness professionals' dialogue about expected and actual organizational roles, responsibilities, and resource capacities within the public health system. Additionally, the identification of specific challenges to inter-organizational communications and information management offer specific areas for intervention.