RESUMEN
In the male mouse germ line, PIWI-interacting RNAs (piRNAs), bound by the PIWI protein MIWI2 (PIWIL4), guide DNA methylation of young active transposons through SPOCD1. However, the underlying mechanisms of SPOCD1-mediated piRNA-directed transposon methylation and whether this pathway functions to protect the human germ line remain unknown. We identified loss-of-function variants in human SPOCD1 that cause defective transposon silencing and male infertility. Through the analysis of these pathogenic alleles, we discovered that the uncharacterized protein C19ORF84 interacts with SPOCD1. DNMT3C, the DNA methyltransferase responsible for transposon methylation, associates with SPOCD1 and C19ORF84 in fetal gonocytes. Furthermore, C19ORF84 is essential for piRNA-directed DNA methylation and male mouse fertility. Finally, C19ORF84 mediates the in vivo association of SPOCD1 with the de novo methylation machinery. In summary, we have discovered a conserved role for the human piRNA pathway in transposon silencing and C19ORF84, an uncharacterized protein essential for orchestrating piRNA-directed DNA methylation.
Asunto(s)
Metilación de ADN , ARN de Interacción con Piwi , Masculino , Humanos , Animales , Ratones , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Proteínas/metabolismo , Células Germinativas/metabolismo , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Elementos Transponibles de ADN/genética , Mamíferos/metabolismoRESUMEN
Heterochromatin is a key architectural feature of eukaryotic chromosomes, which endows particular genomic domains with specific functional properties. The capacity of heterochromatin to restrain the activity of mobile elements, isolate DNA repair in repetitive regions and ensure accurate chromosome segregation is crucial for maintaining genomic stability. Nucleosomes at heterochromatin regions display histone post-translational modifications that contribute to developmental regulation by restricting lineage-specific gene expression. The mechanisms of heterochromatin establishment and of heterochromatin maintenance are separable and involve the ability of sequence-specific factors bound to nascent transcripts to recruit chromatin-modifying enzymes. Heterochromatin can spread along the chromatin from nucleation sites. The propensity of heterochromatin to promote its own spreading and inheritance is counteracted by inhibitory factors. Because of its importance for chromosome function, heterochromatin has key roles in the pathogenesis of various human diseases. In this Review, we discuss conserved principles of heterochromatin formation and function using selected examples from studies of a range of eukaryotes, from yeast to human, with an emphasis on insights obtained from unicellular model organisms.
Asunto(s)
Ensamble y Desensamble de Cromatina/genética , Ensamble y Desensamble de Cromatina/fisiología , Heterocromatina/genética , Heterocromatina/metabolismo , Envejecimiento Prematuro/genética , Animales , Diferenciación Celular/genética , Metilación de ADN , Reparación del ADN , Epigénesis Genética , Silenciador del Gen , Humanos , Modelos Biológicos , Obesidad/genética , ARN de Hongos/genética , ARN de Hongos/metabolismo , ARN no Traducido/genética , ARN no Traducido/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Latencia del Virus/genéticaRESUMEN
Centromeres are maintained epigenetically by the presence of CENP-A, an evolutionarily conserved histone H3 variant, which directs kinetochore assembly and hence centromere function. To identify factors that promote assembly of CENP-A chromatin, we affinity-selected solubilized fission yeast CENP-ACnp1 chromatin. All subunits of the Ino80 complex were enriched, including the auxiliary subunit Hap2. Chromatin association of Hap2 is Ies4-dependent. In addition to a role in maintenance of CENP-ACnp1 chromatin integrity at endogenous centromeres, Hap2 is required for de novo assembly of CENP-ACnp1 chromatin on naïve centromere DNA and promotes H3 turnover on centromere regions and other loci prone to CENP-ACnp1 deposition. Prior to CENP-ACnp1 chromatin assembly, Hap2 facilitates transcription from centromere DNA. These analyses suggest that Hap2-Ino80 destabilizes H3 nucleosomes on centromere DNA through transcription-coupled histone H3 turnover, driving the replacement of resident H3 nucleosomes with CENP-ACnp1 nucleosomes. These inherent properties define centromere DNA by directing a program that mediates CENP-ACnp1 assembly on appropriate sequences.
Asunto(s)
Cromatina/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Transcripción Genética/fisiología , Cromatina/genética , Proteínas Cromosómicas no Histona/metabolismo , Cromosomas Fúngicos/genética , Cromosomas Fúngicos/metabolismo , ADN de Hongos/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Factores de Transcripción/metabolismoRESUMEN
Alternative transcription start site (TSS) usage regulation has been identified as a major means of gene expression regulation in metazoans. However, in fungi, its impact remains elusive as its study has thus far been restricted to model yeasts. Here, we first re-analyzed TSS-seq data to define genuine TSS clusters in 2 species of pathogenic Cryptococcus. We identified 2 types of TSS clusters associated with specific DNA sequence motifs. Our analysis also revealed that alternative TSS usage regulation in response to environmental cues is widespread in Cryptococcus, altering gene expression and protein targeting. Importantly, we performed a forward genetic screen to identify a unique transcription factor (TF) named Tur1, which regulates alternative TSS (altTSS) usage genome-wide when cells switch from exponential phase to stationary phase. ChiP-Seq and DamID-Seq analyses suggest that at some loci, the role of Tur1 might be direct. Tur1 has been previously shown to be essential for virulence in C. neoformans. We demonstrated here that a tur1Δ mutant strain is more sensitive to superoxide stress and phagocytosed more efficiently by macrophages than the wild-type (WT) strain.
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Proteínas Fúngicas , Regulación Fúngica de la Expresión Génica , Genoma Fúngico , Factores de Transcripción , Sitio de Iniciación de la Transcripción , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Cryptococcus/genética , Cryptococcus/patogenicidad , Cryptococcus/metabolismo , Cryptococcus neoformans/genética , Cryptococcus neoformans/patogenicidad , Cryptococcus neoformans/metabolismo , Macrófagos/microbiología , Macrófagos/metabolismo , Animales , Ratones , Virulencia/genética , Fagocitosis/genéticaRESUMEN
The 1858C>T allele of the tyrosine phosphatase PTPN22 is present in 5-10% of the North American population and is strongly associated with numerous autoimmune diseases. Although research has been done to define how this allele potentiates autoimmunity, the influence PTPN22 and its pro-autoimmune allele has in anti-viral immunity remains poorly defined. Here, we use single cell RNA-sequencing and functional studies to interrogate the impact of this pro-autoimmune allele on anti-viral immunity during Lymphocytic Choriomeningitis Virus clone 13 (LCMV-cl13) infection. Mice homozygous for this allele (PEP-619WW) clear the LCMV-cl13 virus whereas wildtype (PEP-WT) mice cannot. This is associated with enhanced anti-viral CD4 T cell responses and a more immunostimulatory CD8α- cDC phenotype. Adoptive transfer studies demonstrated that PEP-619WW enhanced anti-viral CD4 T cell function through virus-specific CD4 T cell intrinsic and extrinsic mechanisms. Taken together, our data show that the pro-autoimmune allele of Ptpn22 drives a beneficial anti-viral immune response thereby preventing what is normally a chronic virus infection.
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Enfermedades Autoinmunes , Coriomeningitis Linfocítica , Animales , Ratones , Alelos , Enfermedades Autoinmunes/genética , Autoinmunidad/genética , Monoéster Fosfórico Hidrolasas/genética , TirosinaRESUMEN
Heterochromatin that depends on histone H3 lysine 9 methylation (H3K9me) renders embedded genes transcriptionally silent1-3. In the fission yeast Schizosaccharomyces pombe, H3K9me heterochromatin can be transmitted through cell division provided the counteracting demethylase Epe1 is absent4,5. Heterochromatin heritability might allow wild-type cells under certain conditions to acquire epimutations, which could influence phenotype through unstable gene silencing rather than DNA change6,7. Here we show that heterochromatin-dependent epimutants resistant to caffeine arise in fission yeast grown with threshold levels of caffeine. Isolates with unstable resistance have distinct heterochromatin islands with reduced expression of embedded genes, including some whose mutation confers caffeine resistance. Forced heterochromatin formation at implicated loci confirms that resistance results from heterochromatin-mediated silencing. Our analyses reveal that epigenetic processes promote phenotypic plasticity, letting wild-type cells adapt to unfavourable environments without genetic alteration. In some isolates, subsequent or coincident gene-amplification events augment resistance. Caffeine affects two anti-silencing factors: Epe1 is downregulated, reducing its chromatin association, and a shortened isoform of Mst2 histone acetyltransferase is expressed. Thus, heterochromatin-dependent epimutation provides a bet-hedging strategy allowing cells to adapt transiently to insults while remaining genetically wild type. Isolates with unstable caffeine resistance show cross-resistance to antifungal agents, suggesting that related heterochromatin-dependent processes may contribute to resistance of plant and human fungal pathogens to such agents.
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Farmacorresistencia Fúngica/genética , Silenciador del Gen , Heterocromatina/genética , Heterocromatina/metabolismo , Schizosaccharomyces/genética , Cafeína/farmacología , Farmacorresistencia Fúngica/efectos de los fármacos , Silenciador del Gen/efectos de los fármacos , Heterocromatina/efectos de los fármacos , Histona Acetiltransferasas/metabolismo , Proteínas Nucleares/metabolismo , Fenotipo , Schizosaccharomyces/citología , Schizosaccharomyces/efectos de los fármacos , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismoRESUMEN
In mammals, the acquisition of the germline from the soma provides the germline with an essential challenge: the need to erase and reset genomic methylation1. In the male germline, RNA-directed DNA methylation silences young, active transposable elements2-4. The PIWI protein MIWI2 (PIWIL4) and its associated PIWI-interacting RNAs (piRNAs) instruct DNA methylation of transposable elements3,5. piRNAs are proposed to tether MIWI2 to nascent transposable element transcripts; however, the mechanism by which MIWI2 directs the de novo methylation of transposable elements is poorly understood, although central to the immortality of the germline. Here we define the interactome of MIWI2 in mouse fetal gonocytes undergoing de novo genome methylation and identify a previously unknown MIWI2-associated factor, SPOCD1, that is essential for the methylation and silencing of young transposable elements. The loss of Spocd1 in mice results in male-specific infertility but does not affect either piRNA biogenesis or the localization of MIWI2 to the nucleus. SPOCD1 is a nuclear protein whose expression is restricted to the period of de novo genome methylation. It co-purifies in vivo with DNMT3L and DNMT3A, components of the de novo methylation machinery, as well as with constituents of the NURD and BAF chromatin remodelling complexes. We propose a model whereby tethering of MIWI2 to a nascent transposable element transcript recruits repressive chromatin remodelling activities and the de novo methylation apparatus through SPOCD1. In summary, we have identified a previously unrecognized and essential executor of mammalian piRNA-directed DNA methylation.
Asunto(s)
Metilación de ADN/genética , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Animales , Proteínas Argonautas/metabolismo , Ensamble y Desensamble de Cromatina , ADN (Citosina-5-)-Metiltransferasas/metabolismo , ADN Metiltransferasa 3A , Elementos Transponibles de ADN/genética , Femenino , Fertilidad/genética , Silenciador del Gen , Genes de Partícula A Intracisternal/genética , Elementos de Nucleótido Esparcido Largo/genética , Masculino , Ratones , ARN Interferente Pequeño/biosíntesis , Espermatogénesis/genéticaRESUMEN
Vomocytosis, also known as nonlytic exocytosis, is a process whereby fully phagocytosed microbes are expelled from phagocytes without discernible damage to either the phagocyte or microbe. Although this phenomenon was first described in the opportunistic fungal pathogen Cryptococcus neoformans in 2006, to date, mechanistic studies have been hampered by an inability to reliably stimulate or inhibit vomocytosis. Here we present the fortuitous discovery that macrophages lacking the scavenger receptor MAcrophage Receptor with COllagenous domain (MARCO), exhibit near-total vomocytosis of internalised cryptococci within a few hours of infection. Marco-/- macrophages also showed elevated vomocytosis of a yeast-locked C. albicans strain, suggesting this to be a broadly relevant observation. We go on to show that MARCO's role in modulating vomocytosis is independent of its role as a phagocytic receptor, suggesting that this protein may play an important and hitherto unrecognised role in modulating macrophage behaviour.
Asunto(s)
Cryptococcus neoformans , Macrófagos , Receptores Inmunológicos , Animales , Ratones , Cryptococcus neoformans/inmunología , Macrófagos/inmunología , Macrófagos/microbiología , Receptores Inmunológicos/metabolismo , Receptores Inmunológicos/inmunología , Receptores Inmunológicos/genética , Candida albicans/inmunología , Fagocitosis/inmunología , Ratones Noqueados , Exocitosis/inmunología , Criptococosis/inmunologíaRESUMEN
The "Amoeboid Predator-Fungal Animal Virulence Hypothesis" posits that interactions with environmental phagocytes shape the evolution of virulence traits in fungal pathogens. In this hypothesis, selection to avoid predation by amoeba inadvertently selects for traits that contribute to fungal escape from phagocytic immune cells. Here, we investigate this hypothesis in the human fungal pathogens Cryptococcus neoformans and Cryptococcus deneoformans. Applying quantitative trait locus (QTL) mapping and comparative genomics, we discovered a cross-species QTL region that is responsible for variation in resistance to amoeba predation. In C. neoformans, this same QTL was found to have pleiotropic effects on melanization, an established virulence factor. Through fine mapping and population genomic comparisons, we identified the gene encoding the transcription factor Bzp4 that underlies this pleiotropic QTL and we show that decreased expression of this gene reduces melanization and increases susceptibility to amoeba predation. Despite the joint effects of BZP4 on amoeba resistance and melanin production, we find no relationship between BZP4 genotype and escape from macrophages or virulence in murine models of disease. Our findings provide new perspectives on how microbial ecology shapes the genetic architecture of fungal virulence, and suggests the need for more nuanced models for the evolution of pathogenesis that account for the complexities of both microbe-microbe and microbe-host interactions.
Asunto(s)
Amoeba , Criptococosis , Cryptococcus neoformans , Animales , Humanos , Ratones , Amoeba/microbiología , Metagenómica , Conducta Predatoria , Cryptococcus neoformans/genética , Criptococosis/genética , Criptococosis/microbiologíaRESUMEN
In fission yeast, RNAi directs heterochromatin formation at centromeres, telomeres, and the mating type locus. Noncoding RNAs transcribed from repeat elements generate siRNAs that are incorporated into the Argonaute-containing RITS complex and direct it to nascent homologous transcripts. This leads to recruitment of the CLRC complex, including the histone methyltransferase Clr4, promoting H3K9 methylation and heterochromatin formation. A key question is what mediates the recruitment of Clr4/CLRC to transcript-bound RITS. We have identified a LIM domain protein, Stc1, that is required for centromeric heterochromatin integrity. Our analyses show that Stc1 is specifically required to establish H3K9 methylation via RNAi, and interacts both with the RNAi effector Ago1, and with the chromatin-modifying CLRC complex. Moreover, tethering Stc1 to a euchromatic locus is sufficient to induce silencing and heterochromatin formation independently of RNAi. We conclude that Stc1 associates with RITS on centromeric transcripts and recruits CLRC, thereby coupling RNAi to chromatin modification.
Asunto(s)
Proteínas Portadoras/metabolismo , Ensamble y Desensamble de Cromatina , Heterocromatina/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas de Ciclo Celular/genética , N-Metiltransferasa de Histona-Lisina , Metiltransferasas/genética , Interferencia de ARN , Proteínas de Schizosaccharomyces pombe/genéticaRESUMEN
Membrane biophysical properties are critical to cell fitness and depend on unsaturated phospholipid acyl tails. These can only be produced in aerobic environments since eukaryotic desaturases require molecular oxygen. This raises the question of how cells maintain bilayer properties in anoxic environments. Using advanced microscopy, molecular dynamics simulations, and lipidomics by mass spectrometry we demonstrated the existence of an alternative pathway to regulate membrane fluidity that exploits phospholipid acyl tail length asymmetry, replacing unsaturated species in the membrane lipidome. We show that the fission yeast, Schizosaccharomyces japonicus, which can grow in aerobic and anaerobic conditions, is capable of utilizing this strategy, whereas its sister species, the well-known model organism Schizosaccharomyces pombe, cannot. The incorporation of asymmetric-tailed phospholipids might be a general adaptation to hypoxic environmental niches.
Asunto(s)
Adaptación Fisiológica , Anaerobiosis , Fosfolípidos , Schizosaccharomyces , Membrana Celular/metabolismo , Fluidez de la Membrana/fisiología , Simulación de Dinámica Molecular , Fosfolípidos/química , Fosfolípidos/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Anaerobiosis/fisiología , Lipidómica , Regulación hacia Arriba , Regulación Fúngica de la Expresión Génica , Temperatura , Estearoil-CoA Desaturasa/genética , Estearoil-CoA Desaturasa/metabolismo , Adaptación Fisiológica/genéticaRESUMEN
Myoendothelial feedback (MEF), the endothelium-dependent vasodilation following sympathetic vasoconstriction (mediated by smooth muscle to endothelium gap junction communication), has been well studied in resistance arteries of males, but not females. We hypothesized that MEF responses would be similar between the sexes, but different in the relative contribution of the underlying nitric oxide and hyperpolarization mechanisms, given that these mechanisms differ between the sexes in agonist-induced endothelium-dependent dilation. We measured MEF responses (diameter changes) of male and female first- to second-order mouse mesenteric arteries to phenylephrine (10 µM) over 30 min using isolated pressure myography ± blinded inhibition of nitric oxide synthase (NOS) using Nω-nitro-l-arginine methyl ester (l-NAME; 0.1-1.0 mM), hyperpolarization using 35 mM KCl, or transient receptor potential vanilloid 4 (TRPV4) channels using GSK219 (0.1-1.0 µM) or RN-1734 (30 µM). MEF was similar [%dilation (means ± SE): males = 26.7 ± 2.0 and females = 26.1 ± 1.9 at 15 min] and significantly inhibited by l-NAME (1.0 mM) at 15 min [%dilation (means ± SE): males = 8.2 ± 3.3, P < 0.01; females = 6.8 ± 1.9, P < 0.001] and over time (P < 0.01) in both sexes. l-NAME (0.1 mM) + 35 mM KCl nearly eliminated MEF in both sexes (P < 0.001-0.0001). Activation of TRPV4 with GSK101 (0.1-10 µM) induced similar dilation between the sexes. Inhibition of TRPV4, which is reportedly involved in the hyperpolarization mechanism, did not inhibit MEF in either sex. Similar expression of eNOS was found between the sexes with Western blot. Thus, MEF is prominent and similar in murine first- and second-order mesenteric resistance arteries of both sexes, and reliant primarily on NOS and secondarily on hyperpolarization, but not TRPV4.NEW & NOTEWORTHY We found that female mesenteric resistance arteries have similar postconstriction dilatory responses (i.e., myoendothelial feedback) to a sympathetic neurotransmitter analog as male arteries. Both sexes use nitric oxide synthase (NOS) and hyperpolarization, but not TRPV4, in this response. Moreover, the key protein involved in this pathway (eNOS) is similarly expressed in these arteries between the sexes. These similarities are surprising given that agonist-induced endothelium-dependent dilatory mechanisms differ in these arteries between the sexes.
Asunto(s)
Óxido Nítrico Sintasa , Canales Catiónicos TRPV , Ratones , Masculino , Femenino , Animales , NG-Nitroarginina Metil Éster/farmacología , Retroalimentación , Canales Catiónicos TRPV/metabolismo , Arterias Mesentéricas/metabolismo , Vasodilatación , Óxido Nítrico/metabolismo , Endotelio Vascular/metabolismoRESUMEN
Nucleosomes composed of histones are the fundamental units around which DNA is wrapped to form chromatin. Transcriptionally active euchromatin or repressive heterochromatin is regulated in part by the addition or removal of histone post-translational modifications (PTMs) by "writer" and "eraser" enzymes, respectively. Nucleosomal PTMs are recognized by a variety of "reader" proteins that alter gene expression accordingly. The histone tails of the evolutionarily divergent eukaryotic parasite Trypanosoma brucei have atypical sequences and PTMs distinct from those often considered universally conserved. Here we identify 65 predicted readers, writers, and erasers of histone acetylation and methylation encoded in the T. brucei genome and, by epitope tagging, systemically localize 60 of them in the parasite's bloodstream form. ChIP-seq shows that 15 candidate proteins associate with regions of RNAPII transcription initiation. Eight other proteins show a distinct distribution with specific peaks at a subset of RNAPII transcription termination regions marked by RNAPIII-transcribed tRNA and snRNA genes. Proteomic analyses identify distinct protein interaction networks comprising known chromatin regulators and novel trypanosome-specific components. Notably, several SET- and Bromo-domain protein networks suggest parallels to RNAPII promoter-associated complexes in conventional eukaryotes. Further, we identify likely components of TbSWR1 and TbNuA4 complexes whose enrichment coincides with the SWR1-C exchange substrate H2A.Z at RNAPII transcription start regions. The systematic approach used provides details of the composition and organization of the chromatin regulatory machinery in T. brucei and establishes a route to explore divergence from eukaryotic norms in an evolutionarily ancient but experimentally accessible eukaryote.
Asunto(s)
Cromatina , Trypanosoma brucei brucei , Cromatina/genética , Cromatina/metabolismo , Nucleosomas/metabolismo , Mapas de Interacción de Proteínas , Proteómica , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismoRESUMEN
ADP-ribosyltransferases (ARTs) mediate the transfer of ADP-ribose from NAD+ to protein or nucleic acid substrates. This modification can be removed by several different types of proteins, including macrodomains. Several ARTs, also known as PARPs, are stimulated by interferon indicating ADP-ribosylation is an important aspect of the innate immune response. All coronaviruses (CoVs) encode for a highly conserved macrodomain (Mac1) that is critical for CoVs to replicate and cause disease, indicating that ADP-ribosylation can effectively control coronavirus infection. Our siRNA screen indicated that PARP12 might inhibit the replication of a murine hepatitis virus (MHV) Mac1 mutant virus in bone-marrow-derived macrophages (BMDMs). To conclusively demonstrate that PARP12 is a key mediator of the antiviral response to CoVs both in cell culture and in vivo, we produced PARP12-/-mice and tested the ability of MHV A59 (hepatotropic/neurotropic) and JHM (neurotropic) Mac1 mutant viruses to replicate and cause disease in these mice. Notably, in the absence of PARP12, Mac1 mutant replication was increased in BMDMs and mice. In addition, liver pathology was also increased in A59-infected mice. However, the PARP12 knockout did not restore Mac1 mutant virus replication to WT virus levels in all cell or tissue types and did not significantly increase the lethality of Mac1 mutant viruses. These results demonstrate that while PARP12 inhibits MHV Mac1 mutant virus infection, additional PARPs or innate immune factors must contribute to the extreme attenuation of this virus in mice. IMPORTANCE Over the last decade, the importance of ADP-ribosyltransferases (ARTs), also known as PARPs, in the antiviral response has gained increased significance as several were shown to either restrict virus replication or impact innate immune responses. However, there are few studies showing ART-mediated inhibition of virus replication or pathogenesis in animal models. We found that the CoV macrodomain (Mac1) was required to prevent ART-mediated inhibition of virus replication in cell culture. Using knockout mice, we found that PARP12, an interferon-stimulated ART, was required to repress the replication of a Mac1 mutant CoV both in cell culture and in mice, demonstrating that PARP12 represses coronavirus replication. However, the deletion of PARP12 did not fully rescue Mac1 mutant virus replication or pathogenesis, indicating that multiple PARPs function to counter coronavirus infection.
Asunto(s)
Genes Virales , Virus de la Hepatitis Murina , Mutación , Poli(ADP-Ribosa) Polimerasas , Replicación Viral , Animales , Ratones , Infecciones por Coronavirus/virología , Modelos Animales de Enfermedad , Interferones/inmunología , Ratones Noqueados , Virus de la Hepatitis Murina/genética , Virus de la Hepatitis Murina/crecimiento & desarrollo , Virus de la Hepatitis Murina/metabolismo , Virus de la Hepatitis Murina/patogenicidad , Especificidad de Órganos , Poli(ADP-Ribosa) Polimerasas/deficiencia , Poli(ADP-Ribosa) Polimerasas/genética , Poli(ADP-Ribosa) Polimerasas/metabolismo , Replicación Viral/genética , Línea CelularRESUMEN
Cryptococcosis is a potentially lethal fungal infection of humans caused by organisms within the Cryptococcus neoformans/gattii species complex. Whilst C. neoformans is a relatively common pathogen of immunocompromised individuals, C. gattii is capable of acting as a primary pathogen of immunocompetent individuals. Within the host, both species undergo morphogenesis to form titan cells: exceptionally large cells that are critical for disease establishment. To date, the induction, defining attributes, and underlying mechanism of titanisation have been mainly characterized in C. neoformans. Here, we report the serendipitous discovery of a simple and robust protocol for in vitro induction of titan cells in C. gattii. Using this in vitro approach, we reveal a remarkably high capacity for titanisation within C. gattii, especially in strains associated with the Pacific Northwest Outbreak, and characterise strain-specific differences within the clade. In particular, this approach demonstrates for the first time that cell size changes, DNA amplification, and budding are not always synchronous during titanisation. Interestingly, however, exhibition of these cell cycle phenotypes was correlated with genes associated with cell cycle progression including CDC11, CLN1, BUB2, and MCM6. Finally, our findings reveal exogenous p-Aminobenzoic acid to be a key inducer of titanisation in this organism. Consequently, this approach offers significant opportunities for future exploration of the underlying mechanism of titanisation in this genus.
Asunto(s)
Cryptococcus gattii , Cryptococcus neoformans , Proteínas Fúngicas , Humanos , Huésped Inmunocomprometido , Componente 6 del Complejo de Mantenimiento de MinicromosomaRESUMEN
[This corrects the article DOI: 10.1371/journal.ppat.1010321.].
RESUMEN
BACKGROUND: Sickle cell disease (SCD) is a genetic disorder and symptoms may be sensitive to environmental stressors. Although it has been hypothesized that exposure to outdoor air pollution could trigger acute SCD events, evidence is limited. METHODS: We obtained SCD administrative data on hospital encounters in South Carolina from 2002 to 2019. We estimated outdoor air pollutant (particulate matter<2.5 µm (PM2.5), ozone (O3), and PM2.5 elemental carbon (EC) concentrations at residential zip codes using spatio-temporal models. Using a random bi-directional, fixed-interval case-crossover study design, we investigated the relationship between air pollution exposure over 1-, 3-, 5-, 9-, and14-day periods with SCD hospital encounters. RESULTS: We studied 8410 patients with 144,129 hospital encounters. We did not observe associations among all patients with SCD and adults for PM2.5, O3, and EC. We observed positive associations among children for 9- and 14-day EC (OR: 1.05 (95% confidence interval (CI): 1.02, 1.08) and OR: 1.05 (95% CI: 1.02, 1.09), respectively) and 9- and 14-day O3 (OR: 1.04 (95%CI: 1.00, 1.08)) for both. CONCLUSIONS: Our findings suggest that short-term (within two-weeks) levels of EC and O3 and may be associated with SCD hospital encounters among children. Two-pollutant model results suggest that EC is more likely responsible for effects on SCD than O3. More research is needed to confirm our findings.
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Contaminantes Atmosféricos , Contaminación del Aire , Anemia de Células Falciformes , Estudios Cruzados , Exposición a Riesgos Ambientales , Material Particulado , Humanos , Anemia de Células Falciformes/epidemiología , South Carolina/epidemiología , Adulto , Masculino , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Femenino , Material Particulado/análisis , Niño , Contaminantes Atmosféricos/análisis , Adolescente , Adulto Joven , Preescolar , Persona de Mediana Edad , Ozono/análisis , Hospitalización/estadística & datos numéricos , LactanteRESUMEN
The National Cancer Institute's (NCI) Health Information National Trends Survey (HINTS) is a nationally representative survey of U.S. adults in which 12-17% of respondents report a cancer history. To increase representation from adult cancer survivors, in 2021, NCI sampled survivors from three Surveillance, Epidemiology, and End Results (SEER) program cancer registries: Iowa, New Mexico, and the Greater Bay Area. Sampling frames were stratified by time since diagnosis and race/ethnicity, with nonmalignant tumors and non-melanoma skin cancers excluded. Participants completed a self-administered postal questionnaire. The overall response rate for HINTS-SEER (N = 1,234) was 12.6%; a non-response bias analysis indicated few demographic differences between respondents and the pool of sampled patients in each registry. Most of the sample was 10+ years since diagnosis (n = 722; 60.2%); 392 respondents were 5 to < 10 years since diagnosis (29.6%); and 120 were < 5 years since diagnosis (10.2%). Common cancers included male reproductive (n = 304; 24.6%), female breast (n = 284; 23.0%), melanoma (n = 119; 9.6%), and gastrointestinal (n = 106; 8.6%). Tumors were mostly localized (67.8%; n = 833), with 22.4% (n = 282) regional, 6.2% (n = 72) distant, and 3.7% (n = 47) unknown. HINTS-SEER data are available by request and may be used for secondary analyses to examine a range of social, behavioral, and healthcare outcomes among cancer survivors.
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Supervivientes de Cáncer , Neoplasias , Adulto , Estados Unidos/epidemiología , Humanos , Masculino , Femenino , Proyectos Piloto , National Cancer Institute (U.S.) , Neoplasias/terapia , Sistema de Registros , Encuestas y Cuestionarios , IncidenciaRESUMEN
The Health Communication and Informatics Research Branch at the U.S. National Cancer Institute was founded in 1999 in response to increasing evidence demonstrating a link between effective health communication and improved cancer-related outcomes and in recognition of the rapid and dramatic technological changes that were transforming health communication at the turn of the 21st century. For the past 25 years, the Health Communication and Informatics Research Branch has been conducting and supporting research at the forefront of emerging cancer communication trends and technologies, making numerous contributions to health communication science, public health, and cancer control practice. In this essay, we provide a brief history of the branch and the context that led to its establishment, discuss contributions made by the branch to health communication research and practice through key projects and initiatives, and conclude by highlighting health communication and informatics research priorities that offer opportunities for significant impact going forward in light of the challenges posed by the current communication environment.
RESUMEN
OBJECTIVE: Digital technologies permit new ways of performing instrumental activities of daily living (iADLs) for older adults, but these approaches are not usually considered in existing iADL measures. The current study investigated how a sample of older adults report using digital versus analog approaches for iADLs. METHOD: 248 older adults completed the Digital and Analog Daily Activities Survey, a newly developed measure of how an individual performs financial, navigation, medication, and other iADLs. RESULTS: The majority of participants reported regularly using digital methods for some iADLs, such as paying bills (67.7%) and using GPS (67.7%). Low digital adopters were older than high adopters (F(2, 245) = 12.24, p < .001), but otherwise the groups did not differ in terms of gender, years of education, or history of neurological disorders. Participants who used digital methods relatively more than analog methods reported greater levels of satisfaction with their approach and fewer daily errors. CONCLUSIONS: Many older adults have adopted digital technologies for supporting daily tasks, which suggests limitations to the validity of current iADL assessments. By capitalizing on existing habits and enriching environments with new technologies, there are opportunities to promote technological reserve in older adults in a manner that sustains daily functioning.