RESUMEN
Differentiation of proinflammatory CD4+ conventional T cells (Tconv) is critical for productive antitumor responses yet their elicitation remains poorly understood. We comprehensively characterized myeloid cells in tumor draining lymph nodes (tdLN) of mice and identified two subsets of conventional type-2 dendritic cells (cDC2) that traffic from tumor to tdLN and present tumor-derived antigens to CD4+ Tconv, but then fail to support antitumor CD4+ Tconv differentiation. Regulatory T cell (Treg) depletion enhanced their capacity to elicit strong CD4+ Tconv responses and ensuing antitumor protection. Analogous cDC2 populations were identified in patients, and as in mice, their abundance relative to Treg predicts protective ICOS+ PD-1lo CD4+ Tconv phenotypes and survival. Further, in melanoma patients with low Treg abundance, intratumoral cDC2 density alone correlates with abundant CD4+ Tconv and with responsiveness to anti-PD-1 therapy. Together, this highlights a pathway that restrains cDC2 and whose reversal enhances CD4+ Tconv abundance and controls tumor growth.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Células Dendríticas/inmunología , Animales , Antígenos de Neoplasias/inmunología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/metabolismo , Diferenciación Celular , Línea Celular Tumoral , Citocinas/metabolismo , Células Dendríticas/citología , Células Dendríticas/metabolismo , Toxina Diftérica/inmunología , Factores de Transcripción Forkhead/metabolismo , Humanos , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/metabolismo , Activación de Linfocitos , Melanoma Experimental/inmunología , Melanoma Experimental/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Quimiocina/metabolismo , Linfocitos T Reguladores/inmunología , Microambiente TumoralRESUMEN
Group 2 innate lymphoid cells (ILC2s) and CD4+ type 2 helper T cells (TH2 cells) are defined by their similar effector cytokines, which together mediate the features of allergic immunity. We found that tissue ILC2s and TH2 cells differentiated independently but shared overlapping effector function programs that were mediated by exposure to the tissue-derived cytokines interleukin 25 (IL-25), IL-33 and thymic stromal lymphopoietin (TSLP). Loss of these three tissue signals did not affect lymph node priming, but abrogated the terminal differentiation of effector TH2 cells and adaptive lung inflammation in a T cell-intrinsic manner. Our findings suggest a mechanism by which diverse perturbations can activate type 2 immunity and reveal a shared local-tissue-elicited checkpoint that can be exploited to control both innate and adaptive allergic inflammation.
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Citocinas/metabolismo , Hipersensibilidad/inmunología , Inmunidad Innata , Interleucina-17/metabolismo , Interleucina-33/metabolismo , Linfocitos/inmunología , Células Th2/inmunología , Inmunidad Adaptativa , Alérgenos/inmunología , Animales , Aspergillus niger , Venenos de Abeja/inmunología , Abejas , Diferenciación Celular , Células Cultivadas , Citocinas/genética , Dermatophagoides farinae , Interleucina-17/genética , Interleucina-33/genética , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Linfopoyetina del Estroma TímicoRESUMEN
In the small intestine, type 2 responses are regulated by a signaling circuit that involves tuft cells and group 2 innate lymphoid cells (ILC2s). Here, we identified the microbial metabolite succinate as an activating ligand for small intestinal (SI) tuft cells. Sequencing analyses of tuft cells isolated from the small intestine, gall bladder, colon, thymus, and trachea revealed that expression of tuft cell chemosensory receptors is tissue specific. SI tuft cells expressed the succinate receptor (SUCNR1), and providing succinate in drinking water was sufficient to induce a multifaceted type 2 immune response via the tuft-ILC2 circuit. The helminth Nippostrongylus brasiliensis and a tritrichomonad protist both secreted succinate as a metabolite. In vivo sensing of the tritrichomonad required SUCNR1, whereas N. brasiliensis was SUCNR1 independent. These findings define a paradigm wherein tuft cells monitor microbial metabolites to initiate type 2 immunity and suggest the existence of other sensing pathways triggering the response to helminths.
Asunto(s)
Inmunidad Mucosa/efectos de los fármacos , Mucosa Intestinal/citología , Mucosa Intestinal/inmunología , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/efectos de los fármacos , Ácido Succínico/farmacología , Animales , Línea Celular , Femenino , Mucosa Intestinal/metabolismo , Intestino Delgado/efectos de los fármacos , Intestino Delgado/inmunología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Nippostrongylus/efectos de los fármacos , Nippostrongylus/inmunología , Nippostrongylus/metabolismo , Especificidad de Órganos , Infecciones por Protozoos/inmunología , Receptores Acoplados a Proteínas G/inmunología , Transducción de Señal/inmunología , Especificidad de la Especie , Infecciones por Strongylida/inmunología , Canales Catiónicos TRPM/metabolismo , Células Th2/inmunología , Tritrichomonas/efectos de los fármacos , Tritrichomonas/inmunología , Tritrichomonas/metabolismoRESUMEN
The maintenance of immunological tolerance requires the deletion of self-reactive T cells in the thymus. The expression of genes encoding tissue-specific antigens (TSAs) by thymic epithelial cells is critical for this process and depends on activity of the transcriptional regulator Aire; however, the molecular mechanisms Aire uses to target loci encoding TSAs are unknown. Here we identified two Aire-interacting proteins known to be involved in gene repression, ATF7ip and MBD1, that were required for Aire's targeting of loci encoding TSAs. Moreover, Mbd1(-/-) mice developed pathological autoimmunity and had a defect in Aire-dependent thymic expression of genes encoding TSAs, which underscores the importance of Aire's interaction with the ATF7ip-MBD1 protein complex in maintaining central tolerance.
Asunto(s)
Tolerancia Central/inmunología , Proteínas de Unión al ADN/inmunología , Regulación de la Expresión Génica/inmunología , Tolerancia Inmunológica , Proteínas Represoras/inmunología , Factores de Transcripción/inmunología , Animales , Autoantígenos/inmunología , Tolerancia Central/genética , Proteínas de Unión al ADN/genética , Citometría de Flujo , Células HEK293 , Humanos , Immunoblotting , Inmunoprecipitación , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Análisis de Secuencia por Matrices de Oligonucleótidos , Unión Proteica , Proteínas Represoras/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción/genética , Transfección , Técnicas del Sistema de Dos Híbridos , Proteína AIRERESUMEN
The thymus is responsible for generating a diverse yet self-tolerant pool of T cells1. Although the thymic medulla consists mostly of developing and mature AIRE+ epithelial cells, recent evidence has suggested that there is far greater heterogeneity among medullary thymic epithelial cells than was previously thought2. Here we describe in detail an epithelial subset that is remarkably similar to peripheral tuft cells that are found at mucosal barriers3. Similar to the periphery, thymic tuft cells express the canonical taste transduction pathway and IL-25. However, they are unique in their spatial association with cornified aggregates, ability to present antigens and expression of a broad diversity of taste receptors. Some thymic tuft cells pass through an Aire-expressing stage and depend on a known AIRE-binding partner, HIPK2, for their development. Notably, the taste chemosensory protein TRPM5 is required for their thymic function through which they support the development and polarization of thymic invariant natural killer T cells and act to establish a medullary microenvironment that is enriched in the type 2 cytokine, IL-4. These findings indicate that there is a compartmentalized medullary environment in which differentiation of a minor and highly specialized epithelial subset has a non-redundant role in shaping thymic function.
Asunto(s)
Células Epiteliales/citología , Células Epiteliales/metabolismo , Interleucina-4/metabolismo , Timocitos/citología , Timo/citología , Timo/metabolismo , Animales , Microambiente Celular , Quinasas Similares a Doblecortina , Femenino , Humanos , Tolerancia Inmunológica/inmunología , Interleucina-4/biosíntesis , Interleucinas/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Proteínas Serina-Treonina Quinasas/metabolismo , Canales Catiónicos TRPM/metabolismo , Timocitos/metabolismo , Timo/anatomía & histología , Factores de Transcripción/deficiencia , Factores de Transcripción/genética , Proteína AIRERESUMEN
Recent fate-mapping studies in mice have provided substantial evidence that mature adult hepatocytes are a major source of new hepatocytes after liver injury. In other systems, integrin αvß8 has a major role in activating transforming growth factor (TGF)-ß, a potent inhibitor of hepatocyte proliferation. We hypothesized that depletion of hepatocyte integrin αvß8 would increase hepatocyte proliferation and accelerate liver regeneration after injury. Using Itgb8flox/flox;Alb-Cre mice to deplete hepatocyte αvß8, after partial hepatectomy, hepatocyte proliferation and liver-to-body weight ratio were significantly increased in Itgb8flox/flox;Alb-Cre mice compared with control mice. Antibody-mediated blockade of hepatocyte αvß8 in vitro, with assessment of TGF-ß signaling pathways by real-time quantitative PCR array, supported the hypothesis that integrin αvß8 inhibition alters hepatocyte TGF-ß signaling toward a pro-regenerative phenotype. A diethylnitrosamine-induced model of hepatocellular carcinoma, used to examine the possibility that this pro-proliferative phenotype might be oncogenic, revealed no difference in either tumor number or size between Itgb8flox/flox;Alb-Cre and control mice. Immunohistochemistry for integrin αvß8 in healthy and injured human liver demonstrated that human hepatocytes express integrin αvß8. Depletion of hepatocyte integrin αvß8 results in increased hepatocyte proliferation and accelerated liver regeneration after partial hepatectomy in mice. These data demonstrate that targeting integrin αvß8 may represent a promising therapeutic strategy to drive liver regeneration in patients with a broad range of liver diseases.
Asunto(s)
Proliferación Celular , Hepatocitos/metabolismo , Integrinas/deficiencia , Regeneración Hepática , Hígado/metabolismo , Transducción de Señal , Animales , Hepatocitos/patología , Hígado/patología , Ratones , Ratones Transgénicos , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
RATIONALE: Quantification of type 2 inflammation provided a molecular basis for heterogeneity in asthma. Non-type 2 pathways that contribute to asthma pathogenesis are not well understood. OBJECTIVES: To identify dysregulated pathways beyond type 2 inflammation. METHODS: We applied RNA sequencing to airway epithelial brushings obtained from subjects with stable mild asthma not on corticosteroids (n = 19) and healthy control subjects (n = 16). Sequencing reads were mapped to human and viral genomes. In the same cohort, and in a separate group with severe asthma (n = 301), we profiled blood gene expression with microarrays. MEASUREMENTS AND MAIN RESULTS: In airway brushings from mild asthma on inhaled corticosteroids, RNA sequencing yielded 1,379 differentially expressed genes (false discovery rate < 0.01). Pathway analysis revealed increased expression of type 2 markers, IFN-stimulated genes (ISGs), and endoplasmic reticulum (ER) stress-related genes. Airway epithelial ISG expression was not associated with type 2 inflammation in asthma or with viral transcripts but was associated with reduced lung function by FEV1 (ρ = -0.72; P = 0.0004). ER stress was confirmed by an increase in XBP1 (X-box binding protein 1) splicing in mild asthma and was associated with both type 2 inflammation and ISG expression. ISGs were also the most activated genes in blood cells in asthma and were correlated with airway ISG expression (ρ = 0.55; P = 0.030). High blood ISG expression in severe asthma was similarly unrelated to type 2 inflammation. CONCLUSIONS: ISG activation is prominent in asthma, independent of viral transcripts, orthogonal to type 2 inflammation, and associated with distinct clinical features. ER stress is associated with both type 2 inflammation and ISG expression.
Asunto(s)
Asma/genética , Asma/fisiopatología , Retículo Endoplásmico/genética , Regulación de la Expresión Génica , Factor 3 Regulador del Interferón/genética , Adulto , Estudios de Casos y Controles , Eosinófilos/inmunología , Femenino , Humanos , Mediadores de Inflamación/metabolismo , Masculino , Persona de Mediana Edad , Estrés Oxidativo/genética , ARN/genética , Valores de Referencia , Sensibilidad y Especificidad , Transducción de SeñalRESUMEN
BACKGROUND: Asthma is characterized by increased airway narrowing in response to nonspecific stimuli. The disorder is influenced by both environmental and genetic factors. Exosomes are nanosized vesicles of endosomal origin released from inflammatory and epithelial cells that have been implicated in asthma. In this study we characterized the microRNA (miRNA) content of exosomes in healthy control subjects and patients with mild intermittent asthma both at unprovoked baseline and in response to environmental challenge. OBJECTIVE: To investigate alterations in bronchoalveolar lavage fluid (BALF) exosomal miRNA profiles due to asthma, and following subway air exposure. METHODS: Exosomes were isolated from BALF from healthy control subjects (n = 10) and patients with mild intermittent asthma (n = 10) after subway and control exposures. Exosomal RNA was analyzed by using microarrays containing probes for 894 human miRNAs, and selected findings were validated with quantitative RT-PCR. Results were analyzed by using multivariate modeling. RESULTS: The presence of miRNAs was confirmed in exosomes from BALF of both asthmatic patients and healthy control subjects. Significant differences in BALF exosomal miRNA was detected for 24 miRNAs with a subset of 16 miRNAs, including members of the let-7 and miRNA-200 families, providing robust classification of patients with mild nonsymptomatic asthma from healthy subjects with 72% cross-validated predictive power (Q(2) = 0.72). In contrast, subway exposure did not cause any significant alterations in miRNA profiles. CONCLUSION: These studies demonstrate substantial differences in exosomal miRNA profiles between healthy subjects and patients with unprovoked, mild, stable asthma. These changes might be important in the inflammatory response leading to bronchial hyperresponsiveness and asthma.
Asunto(s)
Asma/genética , Exosomas/genética , MicroARNs/análisis , Adolescente , Adulto , Contaminantes Atmosféricos/toxicidad , Asma/fisiopatología , Líquido del Lavado Bronquioalveolar/química , Estudios de Casos y Controles , Citocinas/genética , Exposición a Riesgos Ambientales , Femenino , Volumen Espiratorio Forzado , Humanos , Quinasas Janus/genética , Masculino , Proteínas Quinasas Activadas por Mitógenos/genética , Factores de Transcripción STAT/genética , Suecia , Capacidad Vital , Adulto JovenRESUMEN
Myeloid cells in the tumor microenvironment (TME) can exist in immunosuppressive and immunostimulatory states that impede or promote antitumor immunity, respectively. Blocking suppressive myeloid cells or increasing stimulatory cells to enhance antitumor immune responses is an area of interest for therapeutic intervention. Triggering receptor expressed on myeloid cells-1 (TREM1) is a proinflammatory receptor that amplifies immune responses. TREM1 is expressed on neutrophils, subsets of monocytes and tissue macrophages, and suppressive myeloid populations in the TME, including tumor-associated neutrophils, monocytes, and tumor-associated macrophages. Depletion or inhibition of immunosuppressive myeloid cells, or stimulation by TREM1-mediated inflammatory signaling, could be used to promote an immunostimulatory TME. We developed PY159, an afucosylated humanized anti-TREM1 monoclonal antibody with enhanced FcγR binding. PY159 is a TREM1 agonist that induces signaling, leading to up-regulation of costimulatory molecules on monocytes and macrophages, production of proinflammatory cytokines and chemokines, and enhancement of T cell activation in vitro. An antibody against mouse TREM1, PY159m, promoted antitumor efficacy in syngeneic mouse tumor models. These results suggest that PY159-mediated agonism of TREM1 on tumoral myeloid cells can promote a proinflammatory TME and offer a promising strategy for immunotherapy.
Asunto(s)
Monocitos , Células Mieloides , Animales , Ratones , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Modelos Animales de Enfermedad , Inmunosupresores , Macrófagos , Receptor Activador Expresado en Células Mieloides 1RESUMEN
In studying the genomes of extinct species, two principal limitations are typically the small quantities of endogenous ancient DNA and its degraded condition, even though products of up to 1,600 base pairs (bp) have been amplified in rare cases. Using small overlapping polymerase chain reaction products, longer stretches of sequences or even whole mitochondrial genomes can be reconstructed, but this approach is limited by the number of amplifications that can be performed from rare samples. Thus, even from well-studied Pleistocene species such as mammoths, ground sloths and cave bears, no DNA sequences of more than about 1,000 bp have been reconstructed. Here we report the complete mitochondrial genome sequence of the Pleistocene woolly mammoth Mammuthus primigenius. We used about 200 mg of bone and a new approach that allows the simultaneous retrieval of multiple sequences from small amounts of degraded DNA. Our phylogenetic analyses show that the mammoth was more closely related to the Asian than to the African elephant. However, the divergence of mammoth, African and Asian elephants occurred over a short time, corresponding to only about 7% of the total length of the phylogenetic tree for the three evolutionary lineages.
Asunto(s)
ADN Mitocondrial/genética , Elefantes/clasificación , Elefantes/genética , Fósiles , Genoma/genética , Filogenia , África , Animales , Asia , Evolución Molecular , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Factores de TiempoRESUMEN
The tumor immune microenvironment (TIME) is commonly infiltrated by diverse collections of myeloid cells. Yet, the complexity of myeloid-cell identity and plasticity has challenged efforts to define bona fide populations and determine their connections to T-cell function and their relationship to patient outcome. Here, we have leveraged single-cell RNA-sequencing analysis of several mouse and human tumors and found that monocyte-macrophage diversity is characterized by a combination of conserved lineage states as well as transcriptional programs accessed along the differentiation trajectory. We also found in mouse models that tumor monocyte-to-macrophage progression was profoundly tied to regulatory T cell (Treg) abundance. In human kidney cancer, heterogeneity in macrophage accumulation and myeloid composition corresponded to variance in, not only Treg density, but also the quality of infiltrating CD8+ T cells. In this way, holistic analysis of monocyte-to-macrophage differentiation creates a framework for critically different immune states.
Asunto(s)
Neoplasias Renales , Monocitos , Animales , Macrófagos , Ratones , Fenotipo , Microambiente TumoralRESUMEN
Converting checkpoint inhibitor (CPI)-resistant individuals to being responsive requires identifying suppressive mechanisms. We identify TREM2+ tumor-associated macrophages (TAMs) as being correlated with exhausted CD8+ tumor-infiltrating lymphocytes (TILs) in mouse syngeneic tumor models and human solid tumors of multiple histological types. Fc domain-enhanced anti-TREM2 monoclonal antibody (mAb) therapy promotes anti-tumor immunity by elimination and modulation of TAM populations, which leads to enhanced CD8+ TIL infiltration and effector function. TREM2+ TAMs are most enriched in individuals with ovarian cancer, where TREM2 expression corresponds to disease grade accompanied by worse recurrence-free survival. In an aggressive orthotopic ovarian cancer model, anti-TREM2 mAb therapy drives potent anti-tumor immunity. These results highlight TREM2 as a highly attractive target for immunotherapy modulation in individuals who are refractory to CPI therapy and likely have a TAM-rich tumor microenvironment.
Asunto(s)
Antineoplásicos Inmunológicos/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Inhibidores de Puntos de Control Inmunológico/farmacología , Glicoproteínas de Membrana/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Receptores Inmunológicos/antagonistas & inhibidores , Macrófagos Asociados a Tumores/efectos de los fármacos , Animales , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Línea Celular Tumoral , Técnicas de Cocultivo , Resistencia a Antineoplásicos , Femenino , Células HEK293 , Humanos , Activación de Linfocitos/efectos de los fármacos , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Glicoproteínas de Membrana/metabolismo , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neoplasias/inmunología , Neoplasias/metabolismo , Neoplasias/patología , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Receptor de Muerte Celular Programada 1/inmunología , Receptor de Muerte Celular Programada 1/metabolismo , Receptores Inmunológicos/metabolismo , Transducción de Señal , Células Tumorales Cultivadas , Microambiente Tumoral , Macrófagos Asociados a Tumores/inmunología , Macrófagos Asociados a Tumores/metabolismoRESUMEN
We have sequenced the complete mitochondrial genome of the extinct American mastodon (Mammut americanum) from an Alaskan fossil that is between 50,000 and 130,000 y old, extending the age range of genomic analyses by almost a complete glacial cycle. The sequence we obtained is substantially different from previously reported partial mastodon mitochondrial DNA sequences. By comparing those partial sequences to other proboscidean sequences, we conclude that we have obtained the first sequence of mastodon DNA ever reported. Using the sequence of the mastodon, which diverged 24-28 million years ago (mya) from the Elephantidae lineage, as an outgroup, we infer that the ancestors of African elephants diverged from the lineage leading to mammoths and Asian elephants approximately 7.6 mya and that mammoths and Asian elephants diverged approximately 6.7 mya. We also conclude that the nuclear genomes of the African savannah and forest elephants diverged approximately 4.0 mya, supporting the view that these two groups represent different species. Finally, we found the mitochondrial mutation rate of proboscideans to be roughly half of the rate in primates during at least the last 24 million years.
Asunto(s)
Evolución Biológica , ADN Mitocondrial/análisis , Elefantes/genética , Fósiles , Genoma Mitocondrial , Animales , Secuencia de Bases , Elefantes/clasificación , Evolución Molecular , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADNRESUMEN
We consider gene trees in three species for which the species tree is known. We show that population subdivision in ancestral species can lead to asymmetry in the frequencies of the two gene trees not concordant with the species tree and, if subdivision is extreme, cause the one of the nonconcordant gene trees to be more probable than the concordant gene tree. Although published data for the human-chimp-gorilla clade and for three species of Drosophila show asymmetry consistent with our model, sequencing error could also account for observed patterns. We show that substantial levels of persistent ancestral subdivision are needed to account for the observed levels of asymmetry found in these two studies.
Asunto(s)
Drosophila/genética , Evolución Molecular , Algoritmos , Alelos , Animales , Linaje de la Célula , Variación Genética , Gorilla gorilla , Humanos , Modelos Genéticos , Modelos Estadísticos , Pan troglodytes , Filogenia , Polimorfismo Genético , ProbabilidadRESUMEN
The tumor microenvironment (TME) of diverse cancer types is often characterized by high levels of infiltrating myeloid cells including monocytes, macrophages, dendritic cells, and granulocytes. These cells perform a variety of functions in the TME, varying from immune suppressive to immune stimulatory roles. In this review, we summarize the different myeloid cell populations in the TME and the intratumoral myeloid targeting approaches that are being clinically investigated, and discuss strategies that identify new myeloid subpopulations within the TME. The TME therapies include agents that modulate the functional activities of myeloid populations, that impact recruitment and survival of myeloid subpopulations, and that functionally reprogram or activate myeloid populations. We discuss the benefits, limitations and potential side effects of these therapeutic approaches.
Asunto(s)
Células Mieloides/inmunología , Células Mieloides/metabolismo , Neoplasias/etiología , Neoplasias/patología , Microambiente Tumoral , Animales , Biomarcadores , Diferenciación Celular , Proliferación Celular , Supervivencia Celular , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Humanos , Inmunomodulación , Macrófagos/inmunología , Macrófagos/metabolismo , Monocitos/inmunología , Monocitos/metabolismo , Neutrófilos/inmunología , Neutrófilos/metabolismo , Microambiente Tumoral/inmunologíaRESUMEN
Intratumoral stimulatory dendritic cells (SDCs) play an important role in stimulating cytotoxic T cells and driving immune responses against cancer. Understanding the mechanisms that regulate their abundance in the tumor microenvironment (TME) could unveil new therapeutic opportunities. We find that in human melanoma, SDC abundance is associated with intratumoral expression of the gene encoding the cytokine FLT3LG. FLT3LG is predominantly produced by lymphocytes, notably natural killer (NK) cells in mouse and human tumors. NK cells stably form conjugates with SDCs in the mouse TME, and genetic and cellular ablation of NK cells in mice demonstrates their importance in positively regulating SDC abundance in tumor through production of FLT3L. Although anti-PD-1 'checkpoint' immunotherapy for cancer largely targets T cells, we find that NK cell frequency correlates with protective SDCs in human cancers, with patient responsiveness to anti-PD-1 immunotherapy, and with increased overall survival. Our studies reveal that innate immune SDCs and NK cells cluster together as an excellent prognostic tool for T cell-directed immunotherapy and that these innate cells are necessary for enhanced T cell tumor responses, suggesting this axis as a target for new therapies.
Asunto(s)
Células Dendríticas/inmunología , Inmunoterapia , Células Asesinas Naturales/inmunología , Microambiente Tumoral/inmunología , Antígenos de Superficie/metabolismo , Comunicación Celular , Supervivencia Celular , Humanos , Linfocitos/metabolismo , Melanoma/inmunología , Melanoma/patología , Proteínas de la Membrana/metabolismo , Análisis de Supervivencia , TrombomodulinaRESUMEN
The gene genealogies of two linked loci in three species are analyzed using a series of Markov chain models. We calculate the probability that the gene tree of one locus is concordant with the species tree, given that the gene tree of the other locus is concordant. We define a threshold value of the recombination rate, r*, to be the rate for which the difference between the conditional probability of concordance and its asymptotic value is reduced to 5% of the initial difference. We find that, although r* depends in a complicated way on the times of speciation and effective population sizes, it is always relatively small, <10/N4, where N4 is the effective size of the species represented by the internal branch of the species tree. Consequently, the concordance of gene trees of neutral loci with the species tree is expected to be on roughly the same length scale on the chromosome as the extent of significant linkage disequilibrium within species unless the effective size of contemporary populations is very different from the effective sizes of their ancestral populations. Both balancing selection and selective sweeps can result in much longer genomic regions having concordant gene trees.
Asunto(s)
Evolución Molecular , Ligamiento Genético , Modelos Genéticos , Filogenia , Animales , Marcadores Genéticos , Humanos , Cadenas de MarkovRESUMEN
Thymic epithelial cells (TECs) support T cell development in the thymus. Cortical thymic epithelial cells (cTECs) facilitate positive selection of developing thymocytes whereas medullary thymic epithelial cells (mTECs) facilitate the deletion of self-reactive thymocytes in order to prevent autoimmunity. The mTEC compartment is highly dynamic with continuous maturation and turnover, but the genetic regulation of these processes remains poorly understood. MicroRNAs (miRNAs) are important regulators of TEC genetic programs since miRNA-deficient TECs are severely defective. However, the individual miRNAs important for TEC maintenance and function and their mechanisms of action remain unknown. Here, we demonstrate that miR-205 is highly and preferentially expressed in mTECs during both thymic ontogeny and in the postnatal thymus. This distinct expression is suggestive of functional importance for TEC biology. Genetic ablation of miR-205 in TECs, however, neither revealed a role for miR-205 in TEC function during homeostatic conditions nor during recovery from thymic stress conditions. Thus, despite its distinct expression, miR-205 on its own is largely dispensable for mTEC biology.
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Células Epiteliales/metabolismo , Regulación de la Expresión Génica/fisiología , MicroARNs/biosíntesis , Timo/metabolismo , Animales , Células Epiteliales/citología , Ratones , Ratones Transgénicos , MicroARNs/genética , Timocitos/citología , Timocitos/metabolismo , Timo/citologíaRESUMEN
Functional characterization of noncoding sequences is crucial for understanding the human genome and learning how genetic variation contributes to disease. 3' untranslated regions (UTRs) are an important class of noncoding sequences, but their functions remain largely uncharacterized. We developed a method for massively parallel functional annotation of sequences from 3' UTRs (fast-UTR) and used this approach to measure the effects of a total of >450 kilobases of 3' UTR sequences from >2,000 human genes on steady-state mRNA abundance, mRNA stability and protein production. We found widespread regulatory effects on mRNA that were coupled to effects on mRNA stability and protein production. Furthermore, we discovered 87 novel cis-regulatory elements and measured the effects of genetic variation within known and novel 3' UTR motifs. This work shows how massively parallel approaches can improve the functional annotation of noncoding sequences, advance our understanding of cis-regulatory mechanisms and quantify the effects of human genetic variation.
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Regiones no Traducidas 3'/genética , Genómica/métodos , Anotación de Secuencia Molecular/métodos , Análisis de Secuencia de ARN/métodos , Genoma Humano , Humanos , MicroARNs/genética , ARN Mensajero/análisis , ARN Mensajero/química , ARN Mensajero/genéticaRESUMEN
It is well understood that antigen-presenting cells (APCs) within tumors typically do not maintain cytotoxic T cell (CTL) function, despite engaging them. Across multiple mouse tumor models and human tumor biopsies, we have delineated the intratumoral dendritic cell (DC) populations as distinct from macrophage populations. Within these, CD103(+) DCs are extremely sparse and yet remarkably capable CTL stimulators. These are uniquely dependent on IRF8, Zbtb46, and Batf3 transcription factors and are generated by GM-CSF and FLT3L cytokines. Regressing tumors have higher proportions of these cells, T-cell-dependent immune clearance relies on them, and abundance of their transcripts in human tumors correlates with clinical outcome. This cell type presents opportunities for prognostic and therapeutic approaches across multiple cancer types.