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Coordination of cellular metabolism is essential for optimal T cell responses. Here, we identify cytosolic acetyl-CoA production as an essential metabolic node for CD8 T cell function in vivo. We show that CD8 T cell responses to infection depend on acetyl-CoA derived from citrate via the enzyme ATP citrate lyase (ACLY). However, ablation of ACLY triggers an alternative, acetate-dependent pathway for acetyl-CoA production mediated by acyl-CoA synthetase short-chain family member 2 (ACSS2). Mechanistically, acetate fuels both the TCA cycle and cytosolic acetyl-CoA production, impacting T cell effector responses, acetate-dependent histone acetylation, and chromatin accessibility at effector gene loci. When ACLY is functional, ACSS2 is not required, suggesting acetate is not an obligate metabolic substrate for CD8 T cell function. However, loss of ACLY renders CD8 T cells dependent on acetate (via ACSS2) to maintain acetyl-CoA production and effector function. Together, ACLY and ACSS2 coordinate cytosolic acetyl-CoA production in CD8 T cells to maintain chromatin accessibility and T cell effector function.
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ATP Citrato (pro-S)-Liasa , Acetatos , Acetilcoenzima A , Linfocitos T CD8-positivos , Cromatina , Ratones Endogámicos C57BL , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Animales , Cromatina/metabolismo , Acetilcoenzima A/metabolismo , ATP Citrato (pro-S)-Liasa/metabolismo , ATP Citrato (pro-S)-Liasa/genética , Ratones , Acetatos/metabolismo , Acetato CoA Ligasa/metabolismo , Acetato CoA Ligasa/genética , Acetilación , Ratones Noqueados , Citosol/metabolismo , Histonas/metabolismoRESUMEN
Data from both bulk and single-cell whole-genome DNA methylation experiments are under-utilized in many ways. This is attributable to inefficient mapping of methylation sequencing reads, routinely discarded genetic information, and neglected read-level epigenetic and genetic linkage information. We introduce the BISulfite-seq Command line User Interface Toolkit (BISCUIT) and its companion R/Bioconductor package, biscuiteer, for simultaneous extraction of genetic and epigenetic information from bulk and single-cell DNA methylation sequencing. BISCUIT's performance, flexibility and standards-compliant output allow large, complex experimental designs to be characterized on clinical timescales. BISCUIT is particularly suited for processing data from single-cell DNA methylation assays, with its excellent scalability, efficiency, and ability to greatly enhance mappability, a key challenge for single-cell studies. We also introduce the epiBED format for single-molecule analysis of coupled epigenetic and genetic information, facilitating the study of cellular and tissue heterogeneity from DNA methylation sequencing.
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Metilación de ADN , Epigénesis Genética , Secuenciación de Nucleótidos de Alto Rendimiento , Programas Informáticos , Epigenómica , Análisis de Secuencia de ADN , SulfitosRESUMEN
Clear cell ovarian carcinoma (CCOC) and endometrioid ovarian carcinoma (ENOC) are ovarian carcinoma histotypes, which are both thought to arise from ectopic endometrial (or endometrial-like) cells through an endometriosis intermediate. How the same cell type of origin gives rise to two morphologically and biologically different histotypes has been perplexing, particularly given that recurrent genetic mutations are common to both and present in nonmalignant precursors. We used RNA transcription analysis to show that the expression profiles of CCOC and ENOC resemble those of normal endometrium at secretory and proliferative phases of the menstrual cycle, respectively. DNA methylation at the promoter of the estrogen receptor (ER) gene (ESR1) was enriched in CCOC, which could potentially lock the cells in the secretory state. Compared with normal secretory-type endometrium, CCOC was further defined by increased expression of cysteine and glutathione synthesis pathway genes and downregulation of the iron antiporter, suggesting iron addiction and highlighting ferroptosis as a potential therapeutic target. Overall, these findings suggest that while CCOC and ENOC arise from the same cell type, these histotypes likely originate from different cell states. This "cell state of origin" model may help to explain the presence of histologic and molecular cancer subtypes arising in other organs. SIGNIFICANCE: Two cancer histotypes diverge from a common cell of origin epigenetically locked in different cell states, highlighting the importance of considering cell state to better understand the cell of origin of cancer.
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Adenocarcinoma de Células Claras , Carcinoma Endometrioide , Endometriosis , Neoplasias Ováricas , Femenino , Humanos , Endometriosis/genética , Endometriosis/metabolismo , Neoplasias Ováricas/patología , Carcinoma Endometrioide/genética , Carcinoma Endometrioide/patología , Carcinoma Epitelial de Ovario , Adenocarcinoma de Células Claras/genética , Adenocarcinoma de Células Claras/metabolismo , HierroRESUMEN
SUMMARY: In whole genome sequencing data, polymerase chain reaction amplification results in duplicate DNA fragments coming from the same location in the genome. The process of preparing a whole genome bisulfite sequencing (WGBS) library, on the other hand, can create two DNA fragments from the same location that should not be considered duplicates. Currently, only one WGBS-aware duplicate marking tool exists. However, it only works with the output from a single tool, does not accept streaming input or output, and requires a substantial amount of memory relative to the input size. Dupsifter provides an aligner-agnostic duplicate marking tool that is lightweight, has streaming capabilities, and is memory efficient. AVAILABILITY AND IMPLEMENTATION: Source code and binaries are freely available at https://github.com/huishenlab/dupsifter under the MIT license. Dupsifter is implemented in C and is supported on macOS and Linux.
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Metilación de ADN , Sulfitos , Secuenciación Completa del Genoma/métodos , Análisis de Secuencia de ADN/métodos , Programas Informáticos , ADN/genéticaRESUMEN
Standard preclinical human tumor models lack a human tumor stroma. However, as stroma contributes to therapeutic resistance, the lack of human stroma may make current models less stringent for testing new therapies. To address this, using patient-derived tumor cells, patient derived cancer-associated mesenchymal stem/progenitor cells, and human endothelial cells, we created a Human Stroma-Patient Derived Xenograft (HS-PDX) tumor model. HS-PDX, compared to the standard PDX model, demonstrate greater resistance to targeted therapy and chemotherapy, and better reflect patient response to therapy. Furthermore, HS-PDX can be grown in mice with humanized bone marrow to create humanized immune stroma patient-derived xenograft (HIS-PDX) models. The HIS-PDX model contains human connective tissues, vascular and immune cell infiltrates. RNA sequencing analysis demonstrated a 94-96% correlation with primary human tumor. Using this model, we demonstrate the impact of human tumor stroma on response to CAR-T cell therapy and immune checkpoint inhibitor therapy. We show an immunosuppressive role for human tumor stroma and that this model can be used to identify immunotherapeutic combinations to overcome stromally mediated immunosuppression. Combined, our data confirm a critical role for human stoma in therapeutic response and indicate that HIS-PDX can be an important tool for preclinical drug testing. Statement of Significance: We developed a tumor model with human stromal, vascular, and immune cells. This model mirrors patient response to chemotherapy, targeted therapy, and immunotherapy, and can be used to study therapy resistance.
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A search for alternative Mycobacterium abscessus treatments led to our interest in the two-component regulator DosRS, which, in Mycobacterium tuberculosis, is required for the bacterium to establish a state of nonreplicating, drug-tolerant persistence in response to a variety of host stresses. We show here that the genetic disruption of dosRS impairs the adaptation of M. abscessus to hypoxia, resulting in decreased bacterial survival after oxygen depletion, reduced tolerance to a number of antibiotics in vitro and in vivo, and the inhibition of biofilm formation. We determined that three antimalarial drugs or drug candidates, artemisinin, OZ277, and OZ439, can target DosS-mediated hypoxic signaling in M. abscessus and recapitulate the phenotypic effects of genetically disrupting dosS. OZ439 displayed bactericidal activity comparable to standard-of-care antibiotics in chronically infected mice, in addition to potentiating the activity of antibiotics used in combination. The identification of antimalarial drugs as potent inhibitors and adjunct inhibitors of M. abscessus in vivo offers repurposing opportunities that could have an immediate impact in the clinic.
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Antimaláricos , Infecciones por Mycobacterium no Tuberculosas , Mycobacterium abscessus , Animales , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Ratones , Pruebas de Sensibilidad Microbiana , Infecciones por Mycobacterium no Tuberculosas/tratamiento farmacológico , Infecciones por Mycobacterium no Tuberculosas/microbiología , Mycobacterium abscessus/fisiologíaRESUMEN
There is both public and scholarly concern that (passive) social media use decreases well-being by providing a fertile ground for harmful (upward) social comparison and envy. The present review critically summarizes evidence on this assumption. We first comprehensively synthesize existing evidence, including both prior reviews and the most recent publications (2019-2021). Results show that earlier research finds social comparison and envy to be common on social media and linked to lower well-being. Yet, increasingly, newer studies contradict this conclusion, finding positive links to well-being as well as heterogeneous, person-specific, conditional, and reverse or reciprocal effects. The review identifies four critical conceptual and methodological limitations of existing evidence, which offer new impulses for future research.
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Celos , Medios de Comunicación Sociales , Fertilidad , Humanos , Comparación SocialRESUMEN
An ensemble Kalman filter reanalysis has been archived in the Research Data Archive at the National Center for Atmospheric Research. It used a CAM6 configuration of the Community Earth System Model (CESM), several million observations per day, and the Data Assimilation Research Testbed (DART). The data saved from this global, [Formula: see text] resolution, 80 member ensemble span 2011-2019. They include ensembles of: sub-daily, real world, atmospheric forcing for use by all of the nonatmospheric models of CESM; weekly, CAM6, restart file sets; 6 hourly, prior hindcast estimates of the assimilated observations; 6 hourly, land model, plant growth variables, and 6 hourly, ensemble mean, gridded, atmospheric analyses. This data can be used for hindcast studies and data assimilation using component models of CESM; CAM6, CLM5, CICE5, POP2. MOM6, MOSART, and CISM; and non-CESM Earth system models. This large dataset (~ 120 Tb) has a unique combination of a large ensemble, high frequency, and multiyear time span, which provides opportunities for robust statistical analysis and use as a machine learning training dataset.
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Mycobacterium tuberculosis colonizes, survives, and grows inside macrophages. In vitro macrophage infection models, using both primary macrophages and cell lines, enable the characterization of the pathogen response to macrophage immune pressure and intracellular environmental cues. We describe methods to propagate and infect primary murine bone marrow-derived macrophages, HoxB8 conditionally immortalized myeloid cells, Max Planck Institute alveolar macrophage-like cells, and J774 and THP-1 macrophage-like cell lines. We also present methods on the characterization of M. tuberculosis intracellular survival and the preparation of infected macrophages for imaging.
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Macrófagos Alveolares/microbiología , Macrófagos/microbiología , Imagen Molecular/métodos , Mycobacterium tuberculosis/crecimiento & desarrollo , Células Mieloides/microbiología , Animales , Células Cultivadas , Humanos , Técnicas In Vitro , Macrófagos/patología , Macrófagos Alveolares/patología , Ratones , Mycobacterium tuberculosis/patogenicidad , Células Mieloides/patologíaRESUMEN
BACKGROUND: With rapidly dropping sequencing cost, the popularity of whole-genome DNA methylation sequencing has been on the rise. Multiple library preparation protocols currently exist. We have performed 22 whole-genome DNA methylation sequencing experiments on snap frozen human samples, and extensively benchmarked common library preparation protocols for whole-genome DNA methylation sequencing, including three traditional bisulfite-based protocols and a new enzyme-based protocol. In addition, different input DNA quantities were compared for two kits compatible with a reduced starting quantity. In addition, we also present bioinformatic analysis pipelines for sequencing data from each of these library types. RESULTS: An assortment of metrics were collected for each kit, including raw read statistics, library quality and uniformity metrics, cytosine retention, and CpG beta value consistency between technical replicates. Overall, the NEBNext Enzymatic Methyl-seq and Swift Accel-NGS Methyl-Seq kits performed quantitatively better than the other two protocols. In addition, the NEB and Swift kits performed well at low-input amounts, validating their utility in applications where DNA is the limiting factor. RESULTS: The NEBNext Enzymatic Methyl-seq kit appeared to be the best option for whole-genome DNA methylation sequencing of high-quality DNA, closely followed by the Swift kit, which potentially works better for degraded samples. Further, a general bioinformatic pipeline is applicable across the four protocols, with the exception of extra trimming needed for the Swift Biosciences's Accel-NGS Methyl-Seq protocol to remove the Adaptase sequence.
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Citosina , Metilación de ADN , Biblioteca de Genes , Humanos , Análisis de Secuencia de ADN , Secuenciación Completa del GenomaRESUMEN
5-Methylcytosine (5mC) oxidases, the ten-eleven translocation (TET) proteins, initiate DNA demethylation, but it is unclear how 5mC oxidation is regulated. We show that the protein SMCHD1 (structural maintenance of chromosomes flexible hinge domain containing 1) is found in complexes with TET proteins and negatively regulates TET activities. Removal of SMCHD1 from mouse embryonic stem (ES) cells induces DNA hypomethylation, preferentially at SMCHD1 target sites and accumulation of 5-hydroxymethylcytosine (5hmC), along with promoter demethylation and activation of the Dux double-homeobox gene. In the absence of SMCHD1, ES cells acquire a two-cell (2c) embryo-like state characterized by activation of an early embryonic transcriptome that is substantially imposed by Dux Using Smchd1/Tet1/Tet2/Tet3 quadruple-knockout cells, we show that DNA demethylation, activation of Dux, and other genes upon SMCHD1 loss depend on TET proteins. These data identify SMCHD1 as an antagonist of the 2c-like state of ES cells and of TET-mediated DNA demethylation.
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Metilación de ADN , Dioxigenasas , Animales , Proteínas Cromosómicas no Histona/metabolismo , Cromosomas , Proteínas de Unión al ADN/metabolismo , Dioxigenasas/genética , Dioxigenasas/metabolismo , Células Madre Embrionarias/metabolismo , Ratones , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismoRESUMEN
Benign peripheral nerve sheath tumors are the clinical hallmark of Neurofibromatosis Type 1. They account for substantial morbidity and mortality in NF1. Cutaneous (CNF) and plexiform neurofibromas (PNF) share nearly identical histology, but maintain different growth rates and risk of malignant conversion. The reasons for this disparate clinical behavior are not well explained by recent genome or transcriptome profiling studies. We hypothesized that CNFs and PNFs are epigenetically distinct tumor types that exhibit differential signaling due to genome-wide and site-specific methylation events. We interrogated the methylation profiles of 45 CNFs and 17 PNFs from NF1 subjects with the Illumina EPIC 850K methylation array. Based on these profiles, we confirm that CNFs and PNFs are epigenetically distinct tumors with broad differences in higher-order chromatin states and specific methylation events altering genes involved in key biological and cellular processes, such as inflammation, RAS/MAPK signaling, actin cytoskeleton rearrangement, and oxytocin signaling. Based on our identification of two separate DMRs associated with alternative leading exons in MAP2K3, we demonstrate differential RAS/MKK3/p38 signaling between CNFs and PNFs. Epigenetic reinforcement of RAS/MKK/p38 was a defining characteristic of CNFs leading to pro-inflammatory signaling and chromatin conformational changes, whereas PNFs signaled predominantly through RAS/MEK. Tumor size also correlated with specific CpG methylation events. Taken together, these findings confirm that NF1 deficiency influences the epigenetic regulation of RAS signaling fates, accounting for observed differences in CNF and PNF clinical behavior. The extension of these findings is that CNFs may respond differently than PNFs to RAS-targeted therapeutics raising the possibility of targeting p38-mediated inflammation for CNF treatment.
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Neurofibroma Plexiforme , Neurofibromatosis 1 , Epigénesis Genética , Epigenómica , Humanos , Neurofibroma Plexiforme/genética , Neurofibromatosis 1/genética , Transducción de SeñalRESUMEN
Rhabdoid tumor (RT) is a pediatric cancer characterized by the inactivation of SMARCB1, a subunit of the SWI/SNF chromatin remodeling complex. Although this deletion is the known oncogenic driver, there are limited effective therapeutic options for these patients. Here we use unbiased screening of cell line panels to identify a heightened sensitivity of rhabdoid tumor to mithramycin and the second-generation analogue EC8042. The sensitivity of MMA and EC8042 was superior to traditional DNA damaging agents and linked to the causative mutation of the tumor, SMARCB1 deletion. Mithramycin blocks SMARCB1-deficient SWI/SNF activity and displaces the complex from chromatin to cause an increase in H3K27me3. This triggers chromatin remodeling and enrichment of H3K27ac at chromHMM-defined promoters to restore cellular differentiation. These effects occurred at concentrations not associated with DNA damage and were not due to global chromatin remodeling or widespread gene expression changes. Importantly, a single 3-day infusion of EC8042 caused dramatic regressions of RT xenografts, recapitulated the increase in H3K27me3, and cellular differentiation described in vitro to completely cure three out of eight mice.
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Tumor Rabdoide , Animales , Diferenciación Celular , Proteínas Cromosómicas no Histona , Humanos , Ratones , Plicamicina/farmacología , Tumor Rabdoide/tratamiento farmacológico , Tumor Rabdoide/genética , Factores de Transcripción/genéticaRESUMEN
In this study, we investigated the global gene expression responses of Elizabethkingia anophelis to iron fluxes in the midgut of female Anopheles stephensi mosquitoes fed sucrose or blood, and in iron-poor or iron-rich culture conditions. Of 3,686 transcripts revealed by RNAseq technology, 218 were upregulated while 112 were down-regulated under iron-poor conditions. Hemolysin gene expression was significantly repressed when cells were grown under iron-rich or high temperature (37°C) conditions. Furthermore, hemolysin gene expression was down-regulated after a blood meal, indicating that E. anophelis cells responded to excess iron and its associated physiological stress by limiting iron loading. By contrast, genes encoding respiratory chain proteins were up-regulated under iron-rich conditions, allowing these iron-containing proteins to chelate intracellular free iron. In vivo studies showed that growth of E. anophelis cells increased 3-fold in blood-fed mosquitoes over those in sucrose-fed ones. Deletion of siderophore synthesis genes led to impaired cell growth in both iron-rich and iron-poor media. Mutants showed more susceptibility to H2O2 toxicity and less biofilm formation than did wild-type cells. Mosquitoes with E. anophelis experimentally colonized in their guts produced more eggs than did those treated with erythromycin or left unmanipulated, as controls. Results reveal that E. anophelis bacteria respond to varying iron concentration in the mosquito gut, harvest iron while fending off iron-associated stress, contribute to lysis of red blood cells, and positively influence mosquito host fecundity.
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In spring 2020, COVID-19 and the ensuing social distancing and stay-at-home orders instigated abrupt changes to employment and educational infrastructure, leading to uncertainty, concern, and stress among United States college students. The media consumption patterns of this and other social groups across the globe were affected, with early evidence suggesting viewers were seeking both pandemic-themed media and reassuring, familiar content. A general increase in media consumption, and increased consumption of specific types of content, may have been due to media use for coping strategies. This paper examines the relationship between the stress and anxiety of university students and their strategic use of media for coping during initial social distancing periods in March-April 2020 using data from a cross-sectional survey. We examine links between specific types of media use with psychological well-being concepts, and examine the moderating roles of traits (hope, optimism, and resilience) as buffers against negative relationships between stress and anxiety and psychological well-being. Our findings indicate that stress was linked to more hedonic and less eudaimonic media use, as well as more avoidant and escapist media-based coping. Anxiety, on the other hand, was linked to more media use in general, specifically more eudaimonic media use and a full range of media-based coping strategies. In turn, escapist media was linked to negative affect, while reframing media and eudaimonic media were linked to positive affect. Avoidant coping was tied to poorer mental health, and humor coping was tied to better mental health. Hedonic and need-satisfying media use were linked to more flourishing. Hope, optimism, and resilience were all predictive of media use, with the latter two traits moderating responses to stress and anxiety. The findings give a nuanced portrait of college students' media use during a pandemic-induced shutdown, showing that media use is closely intertwined with well-being in both adaptive and maladaptive patterns.
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OBJECTIVE: Our objective was to examine the appropriateness of cardiac troponin (cTn) testing among patients with cTn increases. METHODS: This is a planned secondary analysis of the Use of TROPonin In Acute coronary syndromes (UTROPIA, NCT02060760) observational cohort study. Appropriateness of cTn testing was adjudicated for emergency department patients with cTn increases >99th percentile and analyzed using both contemporary and high-sensitivity (hs) cTnI assays according to sub-specialty, diagnoses, and symptoms. RESULTS: Appropriateness was determined from 1272 and 1078 adjudication forms completed for 497 and 422 patients with contemporary and hs-cTnI increases, respectively. Appropriateness of cTnI testing across adjudication forms was 71.5% and 72.0% for cTnI and hs-cTnI, respectively. Compared with emergency physicians, cardiologists were less likely to classify cTnI orders as appropriate (cTnI: 79% vs 56%, P < .0001; hs-cTnI: 82% vs 51%, P < .0001). For contemporary cTnI, appropriateness of 95%, 70%, and 39% was observed among adjudication forms completed by cardiologists for type 1 myocardial infarction, type 2 myocardial infarction, and myocardial injury, respectively; compared with 90%, 86%, and 71%, respectively, among emergency physicians. Similar findings were observed using hs-cTnI. Discordance in appropriateness adjudication forms occurred most frequently in cases of myocardial injury (62% both assays) or type 2 myocardial infarction (cTnI 31%; hs-cTnI 23%). CONCLUSIONS: Marked differences exist in the perception of what constitutes appropriate clinical use of cTn testing between cardiologists and emergency physicians, with emergency physicians more likely to see testing as appropriate across a range of clinical scenarios. Discordance derives most often from cases classified as myocardial injury or type 2 myocardial infarction.
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Síndrome Coronario Agudo/sangre , Troponina C/sangre , Adulto , Biomarcadores/sangre , Cardiología/estadística & datos numéricos , Servicio de Urgencia en Hospital/estadística & datos numéricos , Femenino , Humanos , Masculino , Infarto del Miocardio/sangre , Infarto del Miocardio/diagnóstico , Pautas de la Práctica en Medicina/estadística & datos numéricosRESUMEN
BACKGROUND: The mitochondrial unfolded protein response (mitoUPR) is a stress response pathway activated by disruption of proteostasis in the mitochondria. This pathway has been proposed to influence lifespan, with studies suggesting that mitoUPR activation has complex effects on longevity. RESULTS: Here, we examined the contribution of the mitoUPR to the survival and lifespan of three long-lived mitochondrial mutants in Caenorhabditis elegans by modulating the levels of ATFS-1, the central transcription factor that mediates the mitoUPR. We found that clk-1, isp-1, and nuo-6 worms all exhibit an ATFS-1-dependent activation of the mitoUPR. While loss of atfs-1 during adulthood does not affect lifespan in any of these strains, absence of atfs-1 during development prevents clk-1 and isp-1 worms from reaching adulthood and reduces the lifespan of nuo-6 mutants. Examining the mechanism by which deletion of atfs-1 reverts nuo-6 lifespan to wild-type, we find that many of the transcriptional changes present in nuo-6 worms are mediated by ATFS-1. Genes exhibiting an ATFS-1-dependent upregulation in nuo-6 worms are enriched for transcripts that function in stress response and metabolism. Consistent, with this finding, loss of atfs-1 abolishes the enhanced stress resistance observed in nuo-6 mutants and prevents upregulation of multiple stress response pathways including the HIF-1-mediated hypoxia response, SKN-1-mediated oxidative stress response and DAF-16-mediated stress response. CONCLUSIONS: Our results suggest that in the long-lived mitochondrial mutant nuo-6 activation of the mitoUPR causes atfs-1-dependent changes in the expression of genes involved in stress response and metabolism, which contributes to the extended longevity observed in this mutant. This work demonstrates that the mitoUPR can modulate multiple stress response pathways and suggests that it is crucial for the development and lifespan of long-lived mitochondrial mutants.
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Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiología , Longevidad/genética , Mutación , Estrés Oxidativo/fisiología , Factores de Transcripción/genética , Animales , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Mitocondrias , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Transducción de Señal , Factores de Transcripción/metabolismo , Respuesta de Proteína DesplegadaRESUMEN
Improving health literacy is increasingly seen as a solution to health problems and inequalities. This study assesses how one of the more recent measures of health literacy, the Health Literacy Skills Instrument - Short Form, performs among African American college students, and ascertains if and how media use relates to health literacy. Results indicate that both the use of health-related websites and apps as well as overall time spent with the media were positively, but conditionally, linked to health literacy. However, findings also pointed to the need for further test development.
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Mild deficits in mitochondrial function have been shown to increase lifespan in multiple species including worms, flies and mice. Here, we study three C. elegans mitochondrial mutants (clk-1, isp-1 and nuo-6) to identify overlapping genetic pathways that contribute to their longevity. We find that genes regulated by the FOXO transcription factor DAF-16 are upregulated in all three strains, and that the transcriptional changes present in these worms overlap significantly with the long-lived insulin-IGF1 signaling pathway mutant daf-2. We show that DAF-16 and multiple DAF-16 interacting proteins (MATH-33, IMB-2, CST-1/2, BAR-1) are required for the full longevity of all three mitochondrial mutants. Our results suggest that the activation of DAF-16 in these mutants results from elevated levels of reactive oxygen species. Overall, this work reveals an overlapping genetic pathway required for longevity in three mitochondrial mutants, and, combined with previous work, demonstrates that DAF-16 is a downstream mediator of lifespan extension in multiple pathways of longevity.
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Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiología , Factores de Transcripción Forkhead/genética , Mitocondrias/genética , Mutación , Especies Reactivas de Oxígeno/metabolismo , Animales , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Longevidad , Estrés OxidativoRESUMEN
Senescence, a state of permanent cell cycle arrest, can be induced by DNA damage. This process, which was initially described in fibroblasts, is now recognized to occur in stem cells. It has been well characterized in cell lines, but there is currently very limited data available on human senescence in vivo. We recently reported that the expression of transposable elements (TE), including endogenous retroviruses, was up-regulated along with inflammatory genes in human senescent hematopoietic stem and progenitor cells (HSPCs) in vivo. The mechanism of regulation of TE expression is not completely understood, but changes in DNA methylation and chromatin modifications are known to alter their expression. In order to elucidate the molecular mechanisms for TE up-regulation after senescence of HSPCs, we employed whole-genome bisulfite sequencing in paired senescent and active human HSPCs in vivo from healthy subjects. We found that the senescent HSPCs exhibited hypomethylated regions in the genome, which were enriched for TEs. This is the first report characterizing the methylome of senescent human HSPCs.