RESUMEN
Innate immune cells adjust to microbial and inflammatory stimuli through a process termed environmental plasticity, which links a given individual stimulus to a unique activated state. Here, we report that activation of human plasmacytoid predendritic cells (pDCs) with a single microbial or cytokine stimulus triggers cell diversification into three stable subpopulations (P1-P3). P1-pDCs (PD-L1+CD80-) displayed a plasmacytoid morphology and specialization for type I interferon production. P3-pDCs (PD-L1-CD80+) adopted a dendritic morphology and adaptive immune functions. P2-pDCs (PD-L1+CD80+) displayed both innate and adaptive functions. Each subpopulation expressed a specific coding- and long-noncoding-RNA signature and was stable after secondary stimulation. P1-pDCs were detected in samples from patients with lupus or psoriasis. pDC diversification was independent of cell divisions or preexisting heterogeneity within steady-state pDCs but was controlled by a TNF autocrine and/or paracrine communication loop. Our findings reveal a novel mechanism for diversity and division of labor in innate immune cells.
Asunto(s)
Citocinas/inmunología , Células Dendríticas/inmunología , Expresión Génica/inmunología , Inmunidad Innata/inmunología , Inmunidad Adaptativa/inmunología , Antígeno B7-1/inmunología , Antígeno B7-1/metabolismo , Antígeno B7-H1/inmunología , Antígeno B7-H1/metabolismo , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Células Dendríticas/metabolismo , Células Dendríticas/ultraestructura , Perfilación de la Expresión Génica/métodos , Humanos , Interferón Tipo I/genética , Interferón Tipo I/inmunología , Interferón Tipo I/metabolismo , Lupus Eritematoso Sistémico/inmunología , Microscopía Electrónica de Transmisión , Orthomyxoviridae/inmunología , Psoriasis/inmunologíaRESUMEN
Individuals differ widely in their immune responses, with age, sex and genetic factors having major roles in this inherent variability1-6. However, the variables that drive such differences in cytokine secretion-a crucial component of the host response to immune challenges-remain poorly defined. Here we investigated 136 variables and identified smoking, cytomegalovirus latent infection and body mass index as major contributors to variability in cytokine response, with effects of comparable magnitudes with age, sex and genetics. We find that smoking influences both innate and adaptive immune responses. Notably, its effect on innate responses is quickly lost after smoking cessation and is specifically associated with plasma levels of CEACAM6, whereas its effect on adaptive responses persists long after individuals quit smoking and is associated with epigenetic memory. This is supported by the association of the past smoking effect on cytokine responses with DNA methylation at specific signal trans-activators and regulators of metabolism. Our findings identify three novel variables associated with cytokine secretion variability and reveal roles for smoking in the short- and long-term regulation of immune responses. These results have potential clinical implications for the risk of developing infections, cancers or autoimmune diseases.
Asunto(s)
Inmunidad Adaptativa , Fumar , Femenino , Humanos , Masculino , Inmunidad Adaptativa/efectos de los fármacos , Inmunidad Adaptativa/genética , Enfermedades Autoinmunes/etiología , Enfermedades Autoinmunes/inmunología , Índice de Masa Corporal , Citocinas/sangre , Citocinas/inmunología , Citomegalovirus/inmunología , Citomegalovirus/patogenicidad , Citomegalovirus/fisiología , Metilación de ADN/efectos de los fármacos , Epigénesis Genética/efectos de los fármacos , Inmunidad Innata/efectos de los fármacos , Inmunidad Innata/genética , Infecciones/etiología , Infecciones/inmunología , Neoplasias/etiología , Neoplasias/inmunología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología , Fumar/efectos adversos , Fumar/sangre , Fumar/genética , Fumar/inmunologíaRESUMEN
Super-enhancers are large clusters of transcriptional enhancers that drive expression of genes that define cell identity. Improved understanding of the roles that super-enhancers play in biology would be afforded by knowing the constellation of factors that constitute these domains and by identifying super-enhancers across the spectrum of human cell types. We describe here the population of transcription factors, cofactors, chromatin regulators, and transcription apparatus occupying super-enhancers in embryonic stem cells and evidence that super-enhancers are highly transcribed. We produce a catalog of super-enhancers in a broad range of human cell types and find that super-enhancers associate with genes that control and define the biology of these cells. Interestingly, disease-associated variation is especially enriched in the super-enhancers of disease-relevant cell types. Furthermore, we find that cancer cells generate super-enhancers at oncogenes and other genes important in tumor pathogenesis. Thus, super-enhancers play key roles in human cell identity in health and in disease.
Asunto(s)
Células Madre Embrionarias/metabolismo , Elementos de Facilitación Genéticos , Neoplasias/genética , Animales , Cromatina/metabolismo , Humanos , Neoplasias/patología , Polimorfismo de Nucleótido Simple , ARN Polimerasa II/metabolismo , Factores de Transcripción/metabolismo , Transcripción GenéticaRESUMEN
Individuals with low socioeconomic status (SES) are at greater risk of contracting and developing severe disease compared with people with higher SES. Age, sex, host genetics, smoking and cytomegalovirus (CMV) serostatus are known to have a major impact on human immune responses and thus susceptibility to infection. However, the impact of SES on immune variability is not well understood or explored. Here, we used data from the Milieu Intérieur project, a study of 1000 healthy volunteers with extensive demographic and biological data, to examine the effect of SES on immune variability. We developed an Elo-rating system using socioeconomic features such as education, income and home ownership status to objectively rank SES in the 1000 donors. We observed sex-specific SES associations, such as females with a low SES having a significantly higher frequency of CMV seropositivity compared with females with high SES, and males with a low SES having a significantly higher frequency of active smoking compared with males with a high SES. Using random forest models, we identified specific immune genes which were significantly associated with SES in both baseline and immune challenge conditions. Interestingly, many of the SES associations were sex stimuli specific, highlighting the complexity of these interactions. Our study provides a new way of computing SES in human populations that can help identify novel SES associations and reinforces biological evidence for SES-dependent susceptibility to infection. This should serve as a basis for further understanding the molecular mechanisms behind SES effects on immune responses and ultimately disease.
Asunto(s)
Infecciones por Citomegalovirus , Clase Social , Humanos , Femenino , Masculino , Adulto , Infecciones por Citomegalovirus/inmunología , Persona de Mediana Edad , Citomegalovirus/inmunología , Inmunidad , Voluntarios Sanos , Adulto JovenRESUMEN
Studying cancer metabolism gives insight into tumorigenic survival mechanisms and susceptibilities. In melanoma, we identify HEXIM1, a transcription elongation regulator, as a melanoma tumor suppressor that responds to nucleotide stress. HEXIM1 expression is low in melanoma. Its overexpression in a zebrafish melanoma model suppresses cancer formation, while its inactivation accelerates tumor onset in vivo. Knockdown of HEXIM1 rescues zebrafish neural crest defects and human melanoma proliferation defects that arise from nucleotide depletion. Under nucleotide stress, HEXIM1 is induced to form an inhibitory complex with P-TEFb, the kinase that initiates transcription elongation, to inhibit elongation at tumorigenic genes. The resulting alteration in gene expression also causes anti-tumorigenic RNAs to bind to and be stabilized by HEXIM1. HEXIM1 plays an important role in inhibiting cancer cell-specific gene transcription while also facilitating anti-cancer gene expression. Our study reveals an important role for HEXIM1 in coupling nucleotide metabolism with transcriptional regulation in melanoma.
Asunto(s)
Melanoma/metabolismo , Factor B de Elongación Transcripcional Positiva/genética , Pirimidinas/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Animales , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Humanos , Melanoma/genética , Melanoma/patología , Melanoma Experimental , Proteínas Oncogénicas/genética , Factores de Transcripción , Transcripción Genética , Proteínas Supresoras de Tumor/genética , Pez Cebra/genética , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
BACKGROUND: Once integrated in the genome of infected cells, HIV-1 provirus is transcribed by the cellular transcription machinery. This process is regulated by both viral and cellular factors, which are necessary for an efficient viral replication as well as for the setting up of viral latency, leading to a repressed transcription of the integrated provirus. RESULTS: In this study, we examined the role of two parameters in HIV-1 LTR promoter activity. We identified DNA topoisomerase1 (TOP1) to be a potent repressor of this promoter and linked this repression to its catalytic domain. Additionally, we confirmed the folding of a Guanine quadruplex (G4) structure in the HIV-1 promoter and its repressive effect. We demonstrated a direct interaction between TOP1 and this G4 structure, providing evidence of a functional relationship between the two repressive elements. Mutations abolishing G4 folding affected TOP1/G4 interaction and hindered G4-dependent inhibition of TOP1 catalytic activity in vitro. As a result, HIV-1 promoter activity was reactivated in a native chromatin environment. Lastly, we noticed an enrichment of predicted G4 sequences in the promoter of TOP1-repressed cellular genes. CONCLUSIONS: Our results demonstrate the formation of a TOP1/G4 complex on the HIV-1 LTR promoter and its repressive effect on the promoter activity. They reveal the existence of a new mechanism of TOP1/G4-dependent transcriptional repression conserved between viral and human genes. This mechanism contrasts with the known property of TOP1 as global transcriptional activator and offers new perspectives for anti-cancer and anti-viral strategies.
Asunto(s)
VIH-1 , Humanos , VIH-1/genética , Guanina , Factores de Transcripción/genética , Cromatina , Duplicado del Terminal Largo de VIH/genética , Transcripción GenéticaRESUMEN
A small set of core transcription factors (TFs) dominates control of the gene expression program in embryonic stem cells and other well-studied cellular models. These core TFs collectively regulate their own gene expression, thus forming an interconnected auto-regulatory loop that can be considered the core transcriptional regulatory circuitry (CRC) for that cell type. There is limited knowledge of core TFs, and thus models of core regulatory circuitry, for most cell types. We recently discovered that genes encoding known core TFs forming CRCs are driven by super-enhancers, which provides an opportunity to systematically predict CRCs in poorly studied cell types through super-enhancer mapping. Here, we use super-enhancer maps to generate CRC models for 75 human cell and tissue types. These core circuitry models should prove valuable for further investigating cell-type-specific transcriptional regulation in healthy and diseased cells.
Asunto(s)
Regulación de la Expresión Génica , Redes Reguladoras de Genes , Factores de Transcripción/metabolismo , Transcripción Genética , Sitios de Unión , Línea Celular , Células Madre Embrionarias Humanas , Humanos , Especificidad de Órganos , Unión ProteicaRESUMEN
Candida albicans is a commensal yeast present in the gut of most healthy individuals but with highly variable concentrations. However, little is known about the host factors that influence colonization densities. We investigated how microbiota, host lifestyle factors, and genetics could shape C. albicans intestinal carriage in 695 healthy individuals from the Milieu Intérieur cohort. C. albicans intestinal carriage was detected in 82.9% of the subjects using quantitative PCR. Using linear mixed models and multiway-ANOVA, we explored C. albicans intestinal levels with regard to gut microbiota composition and lifestyle factors including diet. By analyzing shotgun metagenomics data and C. albicans qPCR data, we showed that Intestinimonas butyriciproducens was the only gut microbiota species whose relative abundance was negatively correlated with C. albicans concentration. Diet is also linked to C. albicans growth, with eating between meals and a low-sodium diet being associated with higher C. albicans levels. Furthermore, by Genome-Wide Association Study, we identified 26 single nucleotide polymorphisms suggestively associated with C. albicans colonization. In addition, we found that the intestinal levels of C. albicans might influence the host immune response, specifically in response to fungal challenge. We analyzed the transcriptional levels of 546 immune genes and the concentration of 13 cytokines after whole blood stimulation with C. albicans cells and showed positive associations between the extent of C. albicans intestinal levels and NLRP3 expression, as well as secreted IL-2 and CXCL5 concentrations. Taken together, these findings open the way for potential new interventional strategies to curb C. albicans intestinal overgrowth.
Asunto(s)
Candida albicans , Microbioma Gastrointestinal , Humanos , Candida albicans/fisiología , Estudio de Asociación del Genoma Completo , Microbioma Gastrointestinal/fisiología , Dieta , InmunidadRESUMEN
The heterochromatin-enriched HP1 proteins play a critical role in regulation of transcription. These proteins contain two related domains known as the chromo- and the chromoshadow-domain. The chromo-domain binds histone H3 tails methylated on lysine 9. However, in vivo and in vitro experiments have shown that the affinity of HP1 proteins to native methylated chromatin is relatively poor and that the opening of chromatin occurring during DNA replication facilitates their binding to nucleosomes. These observations prompted us to investigate whether HP1 proteins have additional histone binding activities, envisioning also affinity for regions potentially occluded by the nucleosome structure. We find that the chromoshadow-domain interacts with histone H3 in a region located partially inside the nucleosomal barrel at the entry/exit point of the nucleosome. Interestingly, this region is also contacted by the catalytic subunits of the human SWI/SNF complex. In vitro, efficient SWI/SNF remodeling requires this contact and is inhibited in the presence of HP1 proteins. The antagonism between SWI/SNF and HP1 proteins is also observed in vivo on a series of interferon-regulated genes. Finally, we show that SWI/SNF activity favors loading of HP1 proteins to chromatin both in vivo and in vitro. Altogether, our data suggest that HP1 chromoshadow-domains can benefit from the opening of nucleosomal structures to bind chromatin and that HP1 proteins use this property to detect and arrest unwanted chromatin remodeling.
Asunto(s)
ADN Helicasas/metabolismo , Heterocromatina/metabolismo , Histonas/metabolismo , Proteínas Nucleares/metabolismo , Factores de Transcripción/metabolismo , Secuencia de Bases , Línea Celular Tumoral , Cromatina/metabolismo , Inmunoprecipitación de Cromatina , Proteínas Cromosómicas no Histona/metabolismo , ADN Helicasas/química , Cartilla de ADN , Humanos , Proteínas Nucleares/química , Reacción en Cadena de la Polimerasa , Conformación Proteica , Interferencia de ARN , Factores de Transcripción/químicaRESUMEN
Tuberculosis (TB) remains a major public health problem and we lack a comprehensive understanding of how Mycobacterium tuberculosis (M. tb) infection impacts host immune responses. We compared the induced immune response to TB antigen, BCG and IL-1ß stimulation between latently M. tb infected individuals (LTBI) and active TB patients. This revealed distinct responses between TB/LTBI at transcriptomic, proteomic and metabolomic levels. At baseline, we identified a novel immune-metabolic association between pregnane steroids, the PPARγ pathway and elevated plasma IL-1ra in TB. We observed dysregulated IL-1 responses after BCG stimulation in TB patients, with elevated IL-1ra responses being explained by upstream TNF differences. Additionally, distinct secretion of IL-1α/IL-1ß in LTBI/TB after BCG stimulation was associated with downstream differences in granzyme mediated cleavage. Finally, IL-1ß driven signalling was dramatically perturbed in TB disease but was completely restored after successful treatment. This study improves our knowledge of how immune responses are altered during TB disease, and may support the design of improved preventive and therapeutic tools, including host-directed strategies.
Asunto(s)
Proteína Antagonista del Receptor de Interleucina 1 , Interleucina-1 , Tuberculosis , Humanos , Vacuna BCG , Proteína Antagonista del Receptor de Interleucina 1/genética , Proteína Antagonista del Receptor de Interleucina 1/inmunología , Interleucina-1/genética , Interleucina-1/inmunología , Redes y Vías Metabólicas , Proteómica , Tuberculosis/tratamiento farmacológico , Tuberculosis/genética , Tuberculosis/inmunologíaRESUMEN
Host immunity to infection with SARS-CoV-2 is highly variable, dictating diverse clinical outcomes ranging from asymptomatic to severe disease and death. We previously reported reduced type I interferon in severe COVID-19 patients preceded clinical worsening. Further studies identified genetic mutations in loci of the TLR3- or TLR7-dependent interferon-I pathways, or neutralizing interferon-I autoantibodies as risk factors for development of COVID-19 pneumonia. Here we show in patient cohorts with different severities of COVID-19, that baseline plasma interferon α measures differ according to the immunoassay used, timing of sampling, the interferon α subtype measured, and the presence of autoantibodies. We also show a consistently reduced induction of interferon-I proteins in hospitalized COVID-19 patients upon immune stimulation, that is not associated with detectable neutralizing autoantibodies against interferon α or interferon ω. Intracellular proteomic analysis shows increased monocyte numbers in hospitalized COVID-19 patients but impaired interferon-I response after stimulation. We confirm this by ex vivo whole blood stimulation with interferon-I which induces transcriptomic responses associated with inflammation in hospitalized COVID-19 patients, that is not seen in controls or non-hospitalized moderate cases. These results may explain the dichotomy of the poor clinical response to interferon-I based treatments in late stage COVID-19, despite the importance of interferon-I in early acute infection and may guide alternative therapeutic strategies.
Asunto(s)
COVID-19 , Interferón Tipo I , Humanos , Proteómica , SARS-CoV-2 , Interferón-alfa , Antivirales , AutoanticuerposRESUMEN
The interleukin-12 (IL-12) family comprises the only heterodimeric cytokines mediating diverse functional effects. We previously reported a striking bimodal IL-12p70 response to lipopolysaccharide (LPS) stimulation in healthy donors. Herein, we demonstrate that interferon ß (IFNß) is a major upstream determinant of IL-12p70 production, which is also associated with numbers and activation of circulating monocytes. Integrative modeling of proteomic, genetic, epigenomic, and cellular data confirms IFNß as key for LPS-induced IL-12p70 and allowed us to compare the relative effects of each of these parameters on variable cytokine responses. Clinical relevance of our findings is supported by reduced IFNß-IL-12p70 responses in patients hospitalized with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or chronically infected with hepatitis C (HCV). Importantly, these responses are resolved after viral clearance. Our systems immunology approach defines a better understanding of IL-12p70 and IFNß in healthy and infected persons, providing insights into how common genetic and epigenetic variation may impact immune responses to bacterial infection.
Asunto(s)
Interferón beta , Interleucina-12 , Receptor Toll-Like 4 , COVID-19/inmunología , COVID-19/metabolismo , COVID-19/virología , Citocinas/inmunología , Citocinas/metabolismo , Humanos , Interferón beta/inmunología , Interferón beta/metabolismo , Interleucina-12/inmunología , Interleucina-12/metabolismo , Lipopolisacáridos/farmacología , Proteómica , SARS-CoV-2/inmunologíaRESUMEN
Transcriptional Regulatory Networks (TRNs) are mainly responsible for the cell-type- or cell-state-specific expression of gene sets from the same DNA sequence. However, so far there are no precise maps of TRNs available for each cell-type or cell-state, and no ideal tool to map those networks clearly and in full from biological samples. In this review, major approaches and tools to map TRNs from high-throughput data are presented, depending on the type of methods or data used to infer them, and their advantages and limitations are discussed. After summarizing the main principles defining the topology and structurefunction relationships in TRNs, an overview of the extensive work done to map TRNs from bulk transcriptomic data will be presented by type of methodological approach. Most recent modellings of TRNs using other types of molecular data or integrating different data types, including single-cell RNA-sequencing and chromatin information, will then be discussed, before briefly concluding with improvements expected to come in the field.
RESUMEN
Pre-messenger RNAs (pre-mRNAs) maturation is initiated cotranscriptionally. It is therefore conceivable that chromatin-borne information participates in alternative splicing. Here we find that elevated levels of trimethylation of histone H3 on Lys9 (H3K9me3) are a characteristic of the alternative exons of several genes including CD44. On this gene the chromodomain protein HP1γ, frequently defined as a transcriptional repressor, facilitates inclusion of the alternative exons via a mechanism involving decreased RNA polymerase II elongation rate. In addition, accumulation of HP1γ on the variant region of the CD44 gene stabilizes association of the pre-mRNA with the chromatin. Altogether, our data provide evidence for localized histone modifications impacting alternative splicing. They further implicate HP1γ as a possible bridging molecule between the chromatin and the maturating mRNA, with a general impact on splicing decisions.