RESUMEN
The properties of dorsal root ganglia (DRG) neurons that innervate the distal colon are poorly defined, hindering our understanding of their roles in normal physiology and gastrointestinal (GI) disease. Here, we report genetically defined subsets of colon-innervating DRG neurons with diverse morphologic and physiologic properties. Four colon-innervating DRG neuron populations are mechanosensitive and exhibit distinct force thresholds to colon distension. The highest threshold population, selectively labeled using Bmpr1b genetic tools, is necessary and sufficient for behavioral responses to high colon distension, which is partly mediated by the mechanosensory ion channel Piezo2. This Aδ-HTMR population mediates behavioral over-reactivity to colon distension caused by inflammation in a model of inflammatory bowel disease. Thus, like cutaneous DRG mechanoreceptor populations, colon-innervating mechanoreceptors exhibit distinct anatomical and physiological properties and tile force threshold space, and genetically defined colon-innervating HTMRs mediate pathophysiological responses to colon distension, revealing a target population for therapeutic intervention.
Asunto(s)
Ganglios Espinales , Mecanorreceptores , Mecanorreceptores/fisiología , Colon , Neuronas , Piel/inervaciónRESUMEN
Fungal microorganisms (mycobiota) comprise a small but immunoreactive component of the human microbiome, yet little is known about their role in human cancers. Pan-cancer analysis of multiple body sites revealed tumor-associated mycobiomes at up to 1 fungal cell per 104 tumor cells. In lung cancer, Blastomyces was associated with tumor tissues. In stomach cancers, high rates of Candida were linked to the expression of pro-inflammatory immune pathways, while in colon cancers Candida was predictive of metastatic disease and attenuated cellular adhesions. Across multiple GI sites, several Candida species were enriched in tumor samples and tumor-associated Candida DNA was predictive of decreased survival. The presence of Candida in human GI tumors was confirmed by external ITS sequencing of tumor samples and by culture-dependent analysis in an independent cohort. These data implicate the mycobiota in the pathogenesis of GI cancers and suggest that tumor-associated fungal DNA may serve as diagnostic or prognostic biomarkers.
Asunto(s)
Neoplasias Pulmonares , Micobioma , Biomarcadores , Candida/genética , ADN de Hongos , Hongos/genética , HumanosRESUMEN
Spatial barcoding technologies have the potential to reveal histological details of transcriptomic profiles; however, they are currently limited by their low resolution. Here, we report Seq-Scope, a spatial barcoding technology with a resolution comparable to an optical microscope. Seq-Scope is based on a solid-phase amplification of randomly barcoded single-molecule oligonucleotides using an Illumina sequencing platform. The resulting clusters annotated with spatial coordinates are processed to expose RNA-capture moiety. These RNA-capturing barcoded clusters define the pixels of Seq-Scope that are â¼0.5-0.8 µm apart from each other. From tissue sections, Seq-Scope visualizes spatial transcriptome heterogeneity at multiple histological scales, including tissue zonation according to the portal-central (liver), crypt-surface (colon) and inflammation-fibrosis (injured liver) axes, cellular components including single-cell types and subtypes, and subcellular architectures of nucleus and cytoplasm. Seq-Scope is quick, straightforward, precise, and easy-to-implement and makes spatial single-cell analysis accessible to a wide group of biomedical researchers.
Asunto(s)
Microscopía , Transcriptoma/genética , Animales , Núcleo Celular/genética , Colon/patología , Regulación de la Expresión Génica , Hepatocitos/metabolismo , Inflamación/genética , Hígado/metabolismo , Masculino , Ratones Endogámicos C57BL , Mitocondrias/genética , ARN/metabolismo , Análisis de la Célula IndividualRESUMEN
The colon is primarily responsible for absorbing fluids. It contains a large number of microorganisms including fungi, which are enriched in its distal segment. The colonic mucosa must therefore tightly regulate fluid influx to control absorption of fungal metabolites, which can be toxic to epithelial cells and lead to barrier dysfunction. How this is achieved remains unknown. Here, we describe a mechanism by which the innate immune system allows rapid quality check of absorbed fluids to avoid intoxication of colonocytes. This mechanism relies on a population of distal colon macrophages that are equipped with "balloon-like" protrusions (BLPs) inserted in the epithelium, which sample absorbed fluids. In the absence of macrophages or BLPs, epithelial cells keep absorbing fluids containing fungal products, leading to their death and subsequent loss of epithelial barrier integrity. These results reveal an unexpected and essential role of macrophages in the maintenance of colon-microbiota interactions in homeostasis. VIDEO ABSTRACT.
Asunto(s)
Microbioma Gastrointestinal/fisiología , Mucosa Intestinal/metabolismo , Macrófagos/metabolismo , Animales , Colon/metabolismo , Células Epiteliales/metabolismo , Epitelio , Femenino , Homeostasis , Inmunidad Innata/inmunología , Mucosa Intestinal/microbiología , Macrófagos/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Microbiota , Transducción de SeñalRESUMEN
Widespread changes to DNA methylation and chromatin are well documented in cancer, but the fate of higher-order chromosomal structure remains obscure. Here we integrated topological maps for colon tumors and normal colons with epigenetic, transcriptional, and imaging data to characterize alterations to chromatin loops, topologically associated domains, and large-scale compartments. We found that spatial partitioning of the open and closed genome compartments is profoundly compromised in tumors. This reorganization is accompanied by compartment-specific hypomethylation and chromatin changes. Additionally, we identify a compartment at the interface between the canonical A and B compartments that is reorganized in tumors. Remarkably, similar shifts were evident in non-malignant cells that have accumulated excess divisions. Our analyses suggest that these topological changes repress stemness and invasion programs while inducing anti-tumor immunity genes and may therefore restrain malignant progression. Our findings call into question the conventional view that tumor-associated epigenomic alterations are primarily oncogenic.
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Cromatina/metabolismo , Cromosomas/metabolismo , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Metilación de ADN , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica/genética , División Celular , Senescencia Celular/genética , Secuenciación de Inmunoprecipitación de Cromatina , Cromosomas/genética , Estudios de Cohortes , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Biología Computacional , Metilación de ADN/genética , Epigenómica , Células HCT116 , Humanos , Hibridación Fluorescente in Situ , Microscopía Electrónica de Transmisión , Simulación de Dinámica Molecular , RNA-Seq , Análisis Espacial , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismoRESUMEN
Mucosal barrier immunity is essential for the maintenance of the commensal microflora and combating invasive bacterial infection. Although immune and epithelial cells are thought to be the canonical orchestrators of this complex equilibrium, here, we show that the enteric nervous system (ENS) plays an essential and non-redundant role in governing the antimicrobial protein (AMP) response. Using confocal microscopy and single-molecule fluorescence in situ mRNA hybridization (smFISH) studies, we observed that intestinal neurons produce the pleiotropic cytokine IL-18. Strikingly, deletion of IL-18 from the enteric neurons alone, but not immune or epithelial cells, rendered mice susceptible to invasive Salmonella typhimurium (S.t.) infection. Mechanistically, unbiased RNA sequencing and single-cell sequencing revealed that enteric neuronal IL-18 is specifically required for homeostatic goblet cell AMP production. Together, we show that neuron-derived IL-18 signaling controls tissue-wide intestinal immunity and has profound consequences on the mucosal barrier and invasive bacterial killing.
Asunto(s)
Inmunidad Mucosa/inmunología , Interleucina-18/inmunología , Mucosa Intestinal/inmunología , Animales , Citocinas/inmunología , Sistema Nervioso Entérico/inmunología , Sistema Nervioso Entérico/metabolismo , Células Epiteliales/inmunología , Femenino , Células Caliciformes/inmunología , Interleucina-18/biosíntesis , Mucosa Intestinal/metabolismo , Intestino Delgado/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/inmunología , Ratas , Ratas Sprague-Dawley , Infecciones por Salmonella/inmunología , Salmonella typhimurium/inmunología , Transducción de Señal/inmunologíaRESUMEN
The enteric nervous system (ENS) coordinates diverse functions in the intestine but has eluded comprehensive molecular characterization because of the rarity and diversity of cells. Here we develop two methods to profile the ENS of adult mice and humans at single-cell resolution: RAISIN RNA-seq for profiling intact nuclei with ribosome-bound mRNA and MIRACL-seq for label-free enrichment of rare cell types by droplet-based profiling. The 1,187,535 nuclei in our mouse atlas include 5,068 neurons from the ileum and colon, revealing extraordinary neuron diversity. We highlight circadian expression changes in enteric neurons, show that disease-related genes are dysregulated with aging, and identify differences between the ileum and proximal/distal colon. In humans, we profile 436,202 nuclei, recovering 1,445 neurons, and identify conserved and species-specific transcriptional programs and putative neuro-epithelial, neuro-stromal, and neuro-immune interactions. The human ENS expresses risk genes for neuropathic, inflammatory, and extra-intestinal diseases, suggesting neuronal contributions to disease.
Asunto(s)
Sistema Nervioso Entérico/citología , Sistema Nervioso Entérico/metabolismo , Regulación del Desarrollo de la Expresión Génica/genética , Neuronas/metabolismo , Cuerpos de Nissl/metabolismo , ARN Mensajero/metabolismo , Análisis de la Célula Individual/métodos , Envejecimiento/genética , Envejecimiento/metabolismo , Animales , Relojes Circadianos/genética , Colon/citología , Colon/metabolismo , Retículo Endoplásmico Rugoso/genética , Retículo Endoplásmico Rugoso/metabolismo , Retículo Endoplásmico Rugoso/ultraestructura , Células Epiteliales/metabolismo , Femenino , Predisposición Genética a la Enfermedad/genética , Humanos , Íleon/citología , Íleon/metabolismo , Inflamación/genética , Inflamación/metabolismo , Enfermedades Intestinales/genética , Enfermedades Intestinales/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microscopía Electrónica de Transmisión , Enfermedades del Sistema Nervioso/genética , Enfermedades del Sistema Nervioso/metabolismo , Neuroglía/citología , Neuroglía/metabolismo , Neuronas/citología , Cuerpos de Nissl/genética , Cuerpos de Nissl/ultraestructura , ARN Mensajero/genética , RNA-Seq , Ribosomas/metabolismo , Ribosomas/ultraestructura , Células del Estroma/metabolismoRESUMEN
The colonic epithelium can undergo multiple rounds of damage and repair, often in response to excessive inflammation. The responsive stem cell that mediates this process is unclear, in part because of a lack of in vitro models that recapitulate key epithelial changes that occur in vivo during damage and repair. Here, we identify a Hopx+ colitis-associated regenerative stem cell (CARSC) population that functionally contributes to mucosal repair in mouse models of colitis. Hopx+ CARSCs, enriched for fetal-like markers, transiently arose from hypertrophic crypts known to facilitate regeneration. Importantly, we established a long-term, self-organizing two-dimensional (2D) epithelial monolayer system to model the regenerative properties and responses of Hopx+ CARSCs. This system can reenact the "homeostasis-injury-regeneration" cycles of epithelial alterations that occur in vivo. Using this system, we found that hypoxia and endoplasmic reticulum stress, insults commonly present in inflammatory bowel diseases, mediated the cyclic switch of cellular status in this process.
Asunto(s)
Técnicas de Cultivo de Célula/métodos , Colon/patología , Células Madre/patología , Células 3T3 , Animales , Colitis/patología , Células Epiteliales/efectos de los fármacos , Células Epiteliales/patología , Proteínas de Homeodominio/metabolismo , Ratones , Modelos Biológicos , Oxígeno/farmacología , Regeneración/efectos de los fármacos , Células Madre/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacosRESUMEN
We performed the first proteogenomic study on a prospectively collected colon cancer cohort. Comparative proteomic and phosphoproteomic analysis of paired tumor and normal adjacent tissues produced a catalog of colon cancer-associated proteins and phosphosites, including known and putative new biomarkers, drug targets, and cancer/testis antigens. Proteogenomic integration not only prioritized genomically inferred targets, such as copy-number drivers and mutation-derived neoantigens, but also yielded novel findings. Phosphoproteomics data associated Rb phosphorylation with increased proliferation and decreased apoptosis in colon cancer, which explains why this classical tumor suppressor is amplified in colon tumors and suggests a rationale for targeting Rb phosphorylation in colon cancer. Proteomics identified an association between decreased CD8 T cell infiltration and increased glycolysis in microsatellite instability-high (MSI-H) tumors, suggesting glycolysis as a potential target to overcome the resistance of MSI-H tumors to immune checkpoint blockade. Proteogenomics presents new avenues for biological discoveries and therapeutic development.
Asunto(s)
Neoplasias del Colon/genética , Neoplasias del Colon/terapia , Proteogenómica/métodos , Apoptosis/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Linfocitos T CD8-positivos , Proliferación Celular/genética , Neoplasias del Colon/metabolismo , Genómica/métodos , Glucólisis , Humanos , Inestabilidad de Microsatélites , Mutación , Fosforilación , Estudios Prospectivos , Proteómica/métodos , Proteína de Retinoblastoma/genética , Proteína de Retinoblastoma/metabolismoRESUMEN
Increased levels of intestinal bile acids (BAs) are a risk factor for colorectal cancer (CRC). Here, we show that the convergence of dietary factors (high-fat diet) and dysregulated WNT signaling (APC mutation) alters BA profiles to drive malignant transformations in Lgr5-expressing (Lgr5+) cancer stem cells and promote an adenoma-to-adenocarcinoma progression. Mechanistically, we show that BAs that antagonize intestinal farnesoid X receptor (FXR) function, including tauro-ß-muricholic acid (T-ßMCA) and deoxycholic acid (DCA), induce proliferation and DNA damage in Lgr5+ cells. Conversely, selective activation of intestinal FXR can restrict abnormal Lgr5+ cell growth and curtail CRC progression. This unexpected role for FXR in coordinating intestinal self-renewal with BA levels implicates FXR as a potential therapeutic target for CRC.
Asunto(s)
Neoplasias Intestinales/metabolismo , Células Madre Neoplásicas/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Animales , Ácidos y Sales Biliares/metabolismo , Línea Celular , Proliferación Celular/genética , Neoplasias Colorrectales/metabolismo , Ácido Desoxicólico/metabolismo , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Neoplasias Intestinales/genética , Intestinos , Hígado , Ratones , Ratones Endogámicos C57BL , Células Madre Neoplásicas/fisiología , Organoides/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , Factores de Riesgo , Transducción de Señal , Ácido Taurocólico/análogos & derivados , Ácido Taurocólico/metabolismo , Vía de Señalización Wnt/genética , Vía de Señalización Wnt/fisiologíaRESUMEN
Lineage tracing provides key insights into the fate of individual cells in complex organisms. Although effective genetic labeling approaches are available in model systems, in humans, most approaches require detection of nuclear somatic mutations, which have high error rates, limited scale, and do not capture cell state information. Here, we show that somatic mutations in mtDNA can be tracked by single-cell RNA or assay for transposase accessible chromatin (ATAC) sequencing. We leverage somatic mtDNA mutations as natural genetic barcodes and demonstrate their utility as highly accurate clonal markers to infer cellular relationships. We track native human cells both in vitro and in vivo and relate clonal dynamics to gene expression and chromatin accessibility. Our approach should allow clonal tracking at a 1,000-fold greater scale than with nuclear genome sequencing, with simultaneous information on cell state, opening the way to chart cellular dynamics in human health and disease.
Asunto(s)
ADN Mitocondrial/genética , Mitocondrias/genética , Secuencia de Bases , Linaje de la Célula , Cromatina , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Genómica/métodos , Células HEK293 , Células Madre Hematopoyéticas/fisiología , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Mutación , Análisis de la Célula Individual , TransposasasRESUMEN
Genome-wide association studies (GWAS) have revealed risk alleles for ulcerative colitis (UC). To understand their cell type specificities and pathways of action, we generate an atlas of 366,650 cells from the colon mucosa of 18 UC patients and 12 healthy individuals, revealing 51 epithelial, stromal, and immune cell subsets, including BEST4+ enterocytes, microfold-like cells, and IL13RA2+IL11+ inflammatory fibroblasts, which we associate with resistance to anti-TNF treatment. Inflammatory fibroblasts, inflammatory monocytes, microfold-like cells, and T cells that co-express CD8 and IL-17 expand with disease, forming intercellular interaction hubs. Many UC risk genes are cell type specific and co-regulated within relatively few gene modules, suggesting convergence onto limited sets of cell types and pathways. Using this observation, we nominate and infer functions for specific risk genes across GWAS loci. Our work provides a framework for interrogating complex human diseases and mapping risk variants to cell types and pathways.
Asunto(s)
Colitis Ulcerosa/patología , Colon/metabolismo , Adulto , Anciano , Anticuerpos Monoclonales/uso terapéutico , Bestrofinas/metabolismo , Antígenos CD8/metabolismo , Estudios de Casos y Controles , Colitis Ulcerosa/tratamiento farmacológico , Colitis Ulcerosa/metabolismo , Colon/patología , Enterocitos/citología , Enterocitos/metabolismo , Femenino , Sitios Genéticos , Estudio de Asociación del Genoma Completo , Humanos , Interleucina-17/metabolismo , Masculino , Persona de Mediana Edad , Factores de Riesgo , Linfocitos T/citología , Linfocitos T/metabolismo , Trombospondinas/metabolismo , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/metabolismo , Adulto JovenRESUMEN
In colorectal cancer patients, a high density of cytotoxic CD8+ T cells in tumors is associated with better prognosis. Using a Stat3 loss-of-function approach in two wnt/ß-catenin-dependent autochthonous models of sporadic intestinal tumorigenesis, we unravel a complex intracellular process in intestinal epithelial cells (IECs) that controls the induction of a CD8+ T cell based adaptive immune response. Elevated mitophagy in IECs causes iron(II)-accumulation in epithelial lysosomes, in turn, triggering lysosomal membrane permeabilization. Subsequent release of proteases into the cytoplasm augments MHC class I presentation and activation of CD8+ T cells via cross-dressing of dendritic cells. Thus, our findings highlight a so-far-unrecognized link between mitochondrial function, lysosomal integrity, and MHC class I presentation in IECs and suggest that therapies triggering mitophagy or inducing LMP in IECs may prove successful in shifting the balance toward anti-tumor immunity in colorectal cancer.
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Inmunidad Adaptativa , Mitofagia , Inmunidad Adaptativa/efectos de los fármacos , Animales , Azoximetano/toxicidad , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/metabolismo , Permeabilidad de la Membrana Celular , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Citocinas/metabolismo , Células Dendríticas/citología , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Femenino , Compuestos Ferrosos/metabolismo , Humanos , Interferón gamma/metabolismo , Interferón gamma/farmacología , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/metabolismo , Lisosomas/metabolismo , Masculino , Ratones , Ratones Noqueados , Mitofagia/efectos de los fármacos , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Tasa de SupervivenciaRESUMEN
Specific microbial signals induce the differentiation of a distinct pool of RORγ+ regulatory T (Treg) cells crucial for intestinal homeostasis. We discovered highly analogous populations of microbiota-dependent Treg cells that promoted tissue regeneration at extra-gut sites, notably acutely injured skeletal muscle and fatty liver. Inflammatory meditators elicited by tissue damage combined with MHC-class-II-dependent T cell activation to drive the accumulation of gut-derived RORγ+ Treg cells in injured muscle, wherein they regulated the dynamics and tenor of early inflammation and helped balance the proliferation vs. differentiation of local stem cells. Reining in IL-17A-producing T cells was a major mechanism underlying the rheostatic functions of RORγ+ Treg cells in compromised tissues. Our findings highlight the importance of gut-trained Treg cell emissaries in controlling the response to sterile injury of non-mucosal tissues.
Asunto(s)
Microbioma Gastrointestinal , Microbiota , Animales , Ratones , Linfocitos T Reguladores , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Ratones Endogámicos C57BLRESUMEN
Tissue-resident memory CD8+ T (TRM) cells are a subset of memory T cells that play a critical role in limiting early pathogen spread and controlling infection. TRM cells exhibit differences across tissues, but their potential heterogeneity among distinct anatomic compartments within the small intestine and colon has not been well recognized. Here, by analyzing TRM cells from the lamina propria and epithelial compartments of the small intestine and colon, we showed that intestinal TRM cells exhibited distinctive patterns of cytokine and granzyme expression along with substantial transcriptional, epigenetic, and functional heterogeneity. The T-box transcription factor Eomes, which represses TRM cell formation in some tissues, exhibited unexpected context-specific regulatory roles in supporting the maintenance of established TRM cells in the small intestine, but not in the colon. Taken together, these data provide previously unappreciated insights into the heterogeneity and differential requirements for the formation vs. maintenance of intestinal TRM cells.
Asunto(s)
Linfocitos T CD8-positivos , Células T de Memoria , Linfocitos T CD8-positivos/metabolismo , Memoria Inmunológica , Intestino Delgado , ColonRESUMEN
BRAF(V600E) mutant colon cancers (CCs) have a characteristic gene expression signature that is also found in some tumors lacking this mutation. Collectively, they are referred to as "BRAF-like" tumors and represent some 20% of CCs. We used a shRNA-based genetic screen focused on genes upregulated in BRAF(V600E) CCs to identify vulnerabilities of this tumor subtype that might be exploited therapeutically. Here, we identify RANBP2 (also known as NUP358) as essential for survival of BRAF-like, but not for non-BRAF-like, CC cells. Suppression of RANBP2 results in mitotic defects only in BRAF-like CC cells, leading to cell death. Mechanistically, RANBP2 silencing reduces microtubule outgrowth from the kinetochores, thereby inducing spindle perturbations, providing an explanation for the observed mitotic defects. We find that BRAF-like CCs display far greater sensitivity to the microtubule poison vinorelbine both in vitro and in vivo, suggesting that vinorelbine is a potential tailored treatment for BRAF-like CCs.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Vinblastina/análogos & derivados , Animales , Antineoplásicos Fitogénicos/administración & dosificación , Células Cultivadas , Neoplasias del Colon/clasificación , Neoplasias del Colon/tratamiento farmacológico , Xenoinjertos , Humanos , Ratones , Ratones Desnudos , Microtúbulos/efectos de los fármacos , Microtúbulos/metabolismo , Chaperonas Moleculares/genética , Trasplante de Neoplasias , Proteínas de Complejo Poro Nuclear/genética , Proteínas Proto-Oncogénicas B-raf/genética , Vinblastina/administración & dosificación , Vinblastina/farmacología , VinorelbinaRESUMEN
While conventional pathogenic protists have been extensively studied, there is an underappreciated constitutive protist microbiota that is an integral part of the vertebrate microbiome. The impact of these species on the host and their potential contributions to mucosal immune homeostasis remain poorly studied. Here, we show that the protozoan Tritrichomonas musculis activates the host epithelial inflammasome to induce IL-18 release. Epithelial-derived IL-18 promotes dendritic cell-driven Th1 and Th17 immunity and confers dramatic protection from mucosal bacterial infections. Along with its role as a "protistic" antibiotic, colonization with T. musculis exacerbates the development of T-cell-driven colitis and sporadic colorectal tumors. Our findings demonstrate a novel mutualistic host-protozoan interaction that increases mucosal host defenses at the cost of an increased risk of inflammatory disease.
Asunto(s)
Colitis/inmunología , Colitis/parasitología , Interacciones Huésped-Parásitos , Inflamasomas/inmunología , Mucosa Intestinal/parasitología , Microbiota/inmunología , Tricomoniasis/inmunología , Trichomonas/inmunología , Animales , Colitis/microbiología , Dientamoeba/inmunología , Inmunidad Mucosa , Interleucina-18/inmunología , Mucosa Intestinal/inmunología , Mucosa Intestinal/microbiología , Ratones , Ratones Endogámicos C57BL , Infecciones por Salmonella/inmunología , Salmonella typhimurium/inmunología , Simbiosis , Células TH1/inmunología , Células Th17/inmunologíaRESUMEN
K-Ras frequently acquires gain-of-function mutations (K-RasG12D being the most common) that trigger significant transcriptomic and proteomic changes to drive tumorigenesis. Nevertheless, oncogenic K-Ras-induced dysregulation of post-transcriptional regulators such as microRNAs (miRNAs) during oncogenesis is poorly understood. Here, we report that K-RasG12D promotes global suppression of miRNA activity, resulting in the upregulation of hundreds of targets. We constructed a comprehensive profile of physiological miRNA targets in mouse colonic epithelium and tumors expressing K-RasG12D using Halo-enhanced Argonaute pull-down. Combining this with parallel datasets of chromatin accessibility, transcriptome, and proteome, we uncovered that K-RasG12D suppressed the expression of Csnk1a1 and Csnk2a1, subsequently decreasing Ago2 phosphorylation at Ser825/829/832/835. Hypo-phosphorylated Ago2 increased binding to mRNAs while reducing its activity to repress miRNA targets. Our findings connect a potent regulatory mechanism of global miRNA activity to K-Ras in a pathophysiological context and provide a mechanistic link between oncogenic K-Ras and the post-transcriptional upregulation of miRNA targets.
Asunto(s)
MicroARNs , Neoplasias , Animales , Ratones , Carcinogénesis/genética , Transformación Celular Neoplásica/genética , Genes ras , MicroARNs/genética , MicroARNs/metabolismo , Neoplasias/genética , ProteómicaRESUMEN
Alterations in the cGAS-STING DNA-sensing pathway affect intestinal homeostasis. We sought to delineate the functional role of STING in intestinal inflammation. Increased STING expression was a feature of intestinal inflammation in mice with colitis and in humans afflicted with inflammatory bowel disease. Mice bearing an allele rendering STING constitutively active exhibited spontaneous colitis and dysbiosis, as well as progressive chronic intestinal inflammation and fibrosis. Bone marrow chimera experiments revealed STING accumulation in intestinal macrophages and monocytes as the initial driver of inflammation. Depletion of Gram-negative bacteria prevented STING accumulation in these cells and alleviated intestinal inflammation. STING accumulation occurred at the protein rather than transcript level, suggesting post-translational stabilization. We found that STING was ubiquitinated in myeloid cells, and this K63-linked ubiquitination could be elicited by bacterial products, including cyclic di-GMP. Our findings suggest a positive feedback loop wherein dysbiosis foments the accumulation of STING in intestinal myeloid cells, driving intestinal inflammation.
Asunto(s)
Colitis/inmunología , Disbiosis/inmunología , Inmunidad Innata/inmunología , Proteínas de la Membrana/inmunología , Células Mieloides/inmunología , Ubiquitinación/inmunología , Animales , Estudios de Casos y Controles , Femenino , Humanos , Inflamación/inmunología , Intestinos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Monocitos/inmunologíaRESUMEN
Cancer is one of the foremost health problems worldwide and is among the leading causes of death in the United States. Gastrointestinal tract cancers account for almost one third of the cancer-related mortality globally, making it one of the deadliest groups of cancers. Early diagnosis and prompt management are key to preventing cancer-related morbidity and mortality. With advancements in technology and endoscopic techniques, endoscopy has become the core in diagnosis and management of gastrointestinal tract cancers. In this extensive review, the authors discuss the role endoscopy plays in early detection, diagnosis, and management of esophageal, gastric, colorectal, pancreatic, ampullary, biliary tract, and small intestinal cancers.