RESUMEN
The signaling lipid sphingosine 1-phosphate (S1P) plays critical roles in an immune response. Drugs targeting S1P signaling have been remarkably successful in treatment of multiple sclerosis, and they have shown promise in clinical trials for colitis and psoriasis. One mechanism of these drugs is to block lymphocyte exit from lymph nodes, where lymphocytes are initially activated, into circulation, from which lymphocytes can reach sites of inflammation. Indeed, S1P can be considered a circulation marker, signaling to immune cells to help them find blood and lymphatic vessels, and to endothelial cells to stabilize the vasculature. That said, S1P plays pleiotropic roles in the immune response, and it will be important to build an integrated view of how S1P shapes inflammation. S1P can function so effectively because its distribution is exquisitely tightly controlled. Here we review how S1P gradients regulate immune cell exit from tissues, with particular attention to key outstanding questions in the field.
Asunto(s)
Movimiento Celular/inmunología , Sistema Inmunológico/inmunología , Sistema Inmunológico/metabolismo , Lisofosfolípidos/metabolismo , Transducción de Señal , Esfingosina/análogos & derivados , Animales , Biomarcadores , Humanos , Sistema Inmunológico/citología , Activación de Linfocitos/inmunología , Linfocitos/inmunología , Linfocitos/metabolismo , Esfingosina/metabolismoRESUMEN
Resident memory T (Trm) cells stably occupy tissues and cannot be sampled in superficial venous blood. Trm cells are heterogeneous but collectively constitute the most abundant memory T cell subset. Trm cells form an integral part of the immune sensing network, monitor for local perturbations in homeostasis throughout the body, participate in protection from infection and cancer, and likely promote autoimmunity, allergy, and inflammatory diseases and impede successful transplantation. Thus Trm cells are major candidates for therapeutic manipulation. Here we review CD8+ and CD4+ Trm ontogeny, maintenance, function, and distribution within lymphoid and nonlymphoid tissues and strategies for their study. We briefly discuss other resident leukocyte populations, including innate lymphoid cells, macrophages, natural killer and natural killer T cells, nonclassical T cells, and memory B cells. Lastly, we highlight major gaps in knowledge and propose ways in which a deeper understanding could result in new methods to prevent or treat diverse human diseases.
Asunto(s)
Linfocitos B/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Células Asesinas Naturales/fisiología , Leucocitos/inmunología , Macrófagos/inmunología , Animales , Movimiento Celular , Humanos , Inmunidad Innata , Memoria Inmunológica , Especificidad de ÓrganosRESUMEN
Professional antigen-presenting cells (APCs) in the skin include dendritic cells, monocytes, and macrophages. They are highly dynamic, with the capacity to enter skin from the peripheral circulation, patrol within tissue, and migrate through lymphatics to draining lymph nodes. Skin APCs are endowed with antigen-sensing, -processing, and -presenting machinery and play key roles in initiating, modulating, and resolving cutaneous inflammation. Skin APCs are a highly heterogeneous population with functionally specialized subsets that are developmentally imprinted and modulated by local tissue microenvironmental and inflammatory cues. This review explores recent advances that have allowed for a more accurate taxonomy of APC subsets found in both mouse and human skin. It also examines the functional specificity of individual APC subsets and their collaboration with other immune cell types that together promote adaptive T cell and regional cutaneous immune responses during homeostasis, inflammation, and disease.
Asunto(s)
Células Presentadoras de Antígenos/inmunología , Células Dendríticas/inmunología , Células de Langerhans/inmunología , Macrófagos/inmunología , Monocitos/inmunología , Piel/inmunología , Linfocitos T/inmunología , Animales , Presentación de Antígeno , Movimiento Celular , Homeostasis , Humanos , Inflamación , Activación de Linfocitos , RatonesRESUMEN
Defective host defenses later in life are associated with changes in immune cell activities, suggesting that age-specific considerations are needed in immunotherapy approaches. In this study, we found that PD-1 and CTLA4-based cancer immunotherapies are unable to eradicate tumors in elderly mice. This defect in anti-tumor activity correlated with two known age-associated immune defects: diminished abundance of systemic naive CD8+ T cells and weak migratory activities of dendritic cells (DCs). We identified a vaccine adjuvant, referred to as a DC hyperactivator, which corrects DC migratory defects in the elderly. Vaccines containing tumor antigens and DC hyperactivators induced T helper type 1 (TH1) CD4+ T cells with cytolytic activity that drive anti-tumor immunity in elderly mice. When administered early in life, DC hyperactivators were the only adjuvant identified that elicited anti-tumor CD4+ T cells that persisted into old age. These results raise the possibility of correcting age-associated immune defects through DC manipulation.
Asunto(s)
Linfocitos T CD4-Positivos , Células Dendríticas , Ratones Endogámicos C57BL , Células Dendríticas/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Ratones , Envejecimiento/inmunología , Linfocitos T CD8-positivos/inmunología , Inmunoterapia/métodos , Vacunas contra el Cáncer/inmunología , Femenino , Neoplasias/inmunología , Neoplasias/terapia , Receptor de Muerte Celular Programada 1/metabolismo , Antígeno CTLA-4/metabolismo , Movimiento Celular , Antígenos de Neoplasias/inmunologíaRESUMEN
The continuous migration of immune cells between lymphoid and nonlymphoid organs is a key feature of the immune system, facilitating the distribution of effector cells within nearly all compartments of the body. Furthermore, reaching their correct position within primary, secondary, or tertiary lymphoid organs is a prerequisite to ensure immune cells' unimpaired differentiation, maturation, and selection, as well as their activation or functional silencing. The superfamilies of chemokines and chemokine receptors are of major importance in guiding immune cells to and within lymphoid and nonlymphoid tissues. In this review we focus on the role of the chemokine system in the migration dynamics of immune cells within lymphoid organs at the steady state and on how these dynamics are affected by infectious and inflammatory processes.
Asunto(s)
Quimiocinas/inmunología , Sistema Inmunológico , Infecciones/inmunología , Inflamación/inmunología , Linfocitos/inmunología , Tejido Linfoide/inmunología , Receptores de Quimiocina/inmunología , Animales , Comunicación Celular , Movimiento Celular , Humanos , Activación de LinfocitosRESUMEN
Membrane tension is thought to be a long-range integrator of cell physiology. Membrane tension has been proposed to enable cell polarity during migration through front-back coordination and long-range protrusion competition. These roles necessitate effective tension transmission across the cell. However, conflicting observations have left the field divided as to whether cell membranes support or resist tension propagation. This discrepancy likely originates from the use of exogenous forces that may not accurately mimic endogenous forces. We overcome this complication by leveraging optogenetics to directly control localized actin-based protrusions or actomyosin contractions while simultaneously monitoring the propagation of membrane tension using dual-trap optical tweezers. Surprisingly, actin-driven protrusions and actomyosin contractions both elicit rapid global membrane tension propagation, whereas forces applied to cell membranes alone do not. We present a simple unifying mechanical model in which mechanical forces that engage the actin cortex drive rapid, robust membrane tension propagation through long-range membrane flows.
Asunto(s)
Actinas , Actomiosina , Actinas/metabolismo , Actomiosina/metabolismo , Citoesqueleto de Actina/metabolismo , Membrana Celular/metabolismo , Movimiento Celular/fisiologíaRESUMEN
In this issue of Cell, Saelens et al. describe a new function for mycobacterial Type VII secretion systems: manipulation of host cell migration. They find that a substantial proportion of global TB cases arise from bacteria lacking this function, raising questions about its role in pathoadaptation of Mycobacterium tuberculosis.
Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Sistemas de Secreción Tipo VII , Humanos , Sistemas de Secreción Tipo VII/metabolismo , Mycobacterium tuberculosis/metabolismo , Tuberculosis/microbiología , Movimiento CelularRESUMEN
Neural migration is a critical step during brain development that requires the interactions of cell-surface guidance receptors. Cancer cells often hijack these mechanisms to disseminate. Here, we reveal crystal structures of Uncoordinated-5 receptor D (Unc5D) in complex with morphogen receptor glypican-3 (GPC3), forming an octameric glycoprotein complex. In the complex, four Unc5D molecules pack into an antiparallel bundle, flanked by four GPC3 molecules. Central glycan-glycan interactions are formed by N-linked glycans emanating from GPC3 (N241 in human) and C-mannosylated tryptophans of the Unc5D thrombospondin-like domains. MD simulations, mass spectrometry and structure-based mutants validate the crystallographic data. Anti-GPC3 nanobodies enhance or weaken Unc5-GPC3 binding and, together with mutant proteins, show that Unc5/GPC3 guide migrating pyramidal neurons in the mouse cortex, and cancer cells in an embryonic xenograft neuroblastoma model. The results demonstrate a conserved structural mechanism of cell guidance, where finely balanced Unc5-GPC3 interactions regulate cell migration.
Asunto(s)
Movimiento Celular , Glipicanos/química , Receptores de Netrina/química , Animales , Glipicanos/metabolismo , Humanos , Ratones , Proteínas Mutantes , Receptores de Netrina/metabolismo , Receptores de Superficie Celular/metabolismo , Anticuerpos de Dominio Único , TrombospondinasRESUMEN
Gasdermins are a family of structurally related proteins originally described for their role in pyroptosis. Gasdermin B (GSDMB) is currently the least studied, and while its association with genetic susceptibility to chronic mucosal inflammatory disorders is well established, little is known about its functional relevance during active disease states. Herein, we report increased GSDMB in inflammatory bowel disease, with single-cell analysis identifying epithelial specificity to inflamed colonocytes/crypt top colonocytes. Surprisingly, mechanistic experiments and transcriptome profiling reveal lack of inherent GSDMB-dependent pyroptosis in activated epithelial cells and organoids but instead point to increased proliferation and migration during in vitro wound closure, which arrests in GSDMB-deficient cells that display hyper-adhesiveness and enhanced formation of vinculin-based focal adhesions dependent on PDGF-A-mediated FAK phosphorylation. Importantly, carriage of disease-associated GSDMB SNPs confers functional defects, disrupting epithelial restitution/repair, which, altogether, establishes GSDMB as a critical factor for restoration of epithelial barrier function and the resolution of inflammation.
Asunto(s)
Células Epiteliales/metabolismo , Células Epiteliales/patología , Enfermedades Inflamatorias del Intestino/metabolismo , Enfermedades Inflamatorias del Intestino/patología , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Piroptosis , Secuencia de Bases , Estudios de Casos y Controles , Adhesión Celular/efectos de los fármacos , Adhesión Celular/genética , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Movimiento Celular/efectos de los fármacos , Movimiento Celular/genética , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Células Epiteliales/efectos de los fármacos , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Células HEK293 , Células HT29 , Humanos , Enfermedades Inflamatorias del Intestino/genética , Metotrexato/farmacología , Mutación/genética , Fosforilación/efectos de los fármacos , Polimorfismo de Nucleótido Simple/genética , Piroptosis/efectos de los fármacos , Piroptosis/genética , Reproducibilidad de los Resultados , Transcriptoma/efectos de los fármacos , Transcriptoma/genética , Regulación hacia Arriba/efectos de los fármacos , Cicatrización de Heridas/efectos de los fármacos , Cicatrización de Heridas/genéticaRESUMEN
Microtubules are essential dynamic polymers composed of α/ß-tubulin heterodimers. They support intracellular trafficking, cell division, cellular motility, and other essential cellular processes. In many species, both α-tubulin and ß-tubulin are encoded by multiple genes with distinct expression profiles and functionality. Microtubules are further diversified through abundant posttranslational modifications, which are added and removed by a suite of enzymes to form complex, stereotyped cellular arrays. The genetic and chemical diversity of tubulin constitute a tubulin code that regulates intrinsic microtubule properties and is read by cellular effectors, such as molecular motors and microtubule-associated proteins, to provide spatial and temporal specificity to microtubules in cells. In this review, we synthesize the rapidly expanding tubulin code literature and highlight limitations and opportunities for the field. As complex microtubule arrays underlie essential physiological processes, a better understanding of how cells employ the tubulin code has important implications for human disease ranging from cancer to neurological disorders.
Asunto(s)
Microtúbulos , Tubulina (Proteína) , Humanos , Tubulina (Proteína)/genética , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo , Microtúbulos/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Procesamiento Proteico-Postraduccional/genética , Movimiento CelularRESUMEN
Immune cells experience large cell shape changes during environmental patrolling because of the physical constraints that they encounter while migrating through tissues. These cells can adapt to such deformation events using dedicated shape-sensing pathways. However, how shape sensing affects immune cell function is mostly unknown. Here, we identify a shape-sensing mechanism that increases the expression of the chemokine receptor CCR7 and guides dendritic cell migration from peripheral tissues to lymph nodes at steady state. This mechanism relies on the lipid metabolism enzyme cPLA2, requires nuclear envelope tensioning and is finely tuned by the ARP2/3 actin nucleation complex. We also show that this shape-sensing axis reprograms dendritic cell transcription by activating an IKKß-NF-κB-dependent pathway known to control their tolerogenic potential. These results indicate that cell shape changes experienced by immune cells can define their migratory behavior and immunoregulatory properties and reveal a contribution of the physical properties of tissues to adaptive immunity.
Asunto(s)
Movimiento Celular , Células Dendríticas , Homeostasis , Ganglios Linfáticos , Ratones Endogámicos C57BL , Receptores CCR7 , Animales , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/citología , Receptores CCR7/metabolismo , Ratones , Movimiento Celular/inmunología , Forma de la Célula , FN-kappa B/metabolismo , Ratones Noqueados , Transducción de Señal/inmunología , Quinasa I-kappa B/metabolismo , Complejo 2-3 Proteico Relacionado con la Actina/metabolismoRESUMEN
Chemokines are chemotactic cytokines that control the migratory patterns and positioning of all immune cells. Although chemokines were initially appreciated as important mediators of acute inflammation, we now know that this complex system of approximately 50 endogenous chemokine ligands and 20 G protein-coupled seven-transmembrane signaling receptors is also critical for the generation of primary and secondary adaptive cellular and humoral immune responses. Recent studies demonstrate important roles for the chemokine system in the priming of naive T cells, in cell fate decisions such as effector and memory cell differentiation, and in regulatory T cell function. In this review, we focus on recent advances in understanding how the chemokine system orchestrates immune cell migration and positioning at the organismic level in homeostasis, in acute inflammation, and during the generation and regulation of adoptive primary and secondary immune responses in the lymphoid system and peripheral nonlymphoid tissue.
Asunto(s)
Quimiocinas/metabolismo , Inmunidad/fisiología , Receptores de Quimiocina/metabolismo , Inmunidad Adaptativa/fisiología , Animales , Movimiento Celular/inmunología , Homeostasis , Humanos , Sistema Inmunológico/citología , Sistema Inmunológico/inmunología , Sistema Inmunológico/metabolismo , Inmunidad Innata/fisiología , Memoria Inmunológica , Inflamación/inmunología , Inflamación/metabolismo , Tejido Linfoide/citología , Tejido Linfoide/inmunología , Tejido Linfoide/metabolismo , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismoRESUMEN
The Rho GTPases - RHOA, RAC1 and CDC42 - are small GTP binding proteins that regulate basic biological processes such as cell locomotion, cell division and morphogenesis by promoting cytoskeleton-based changes in the cell cortex. This regulation results from active (GTP-bound) Rho GTPases stimulating target proteins that, in turn, promote actin assembly and myosin 2-based contraction to organize the cortex. This basic regulatory scheme, well supported by in vitro studies, led to the natural assumption that Rho GTPases function in vivo in an essentially linear matter, with a given process being initiated by GTPase activation and terminated by GTPase inactivation. However, a growing body of evidence based on live cell imaging, modelling and experimental manipulation indicates that Rho GTPase activation and inactivation are often tightly coupled in space and time via signalling circuits and networks based on positive and negative feedback. In this Review, we present and discuss this evidence, and we address one of the fundamental consequences of coupled activation and inactivation: the ability of the Rho GTPases to self-organize, that is, direct their own transition from states of low order to states of high order. We discuss how Rho GTPase self-organization results in the formation of diverse spatiotemporal cortical patterns such as static clusters, oscillatory pulses, travelling wave trains and ring-like waves. Finally, we discuss the advantages of Rho GTPase self-organization and pattern formation for cell function.
Asunto(s)
Citoesqueleto , Proteínas de Unión al GTP rho , Proteínas de Unión al GTP rho/metabolismo , Citoesqueleto/metabolismo , Actinas/metabolismo , Transducción de Señal , Movimiento Celular , Proteína de Unión al GTP rac1/metabolismoRESUMEN
Damaged mitochondria need to be cleared to maintain the quality of the mitochondrial pool. Here, we report mitocytosis, a migrasome-mediated mitochondrial quality-control process. We found that, upon exposure to mild mitochondrial stresses, damaged mitochondria are transported into migrasomes and subsequently disposed of from migrating cells. Mechanistically, mitocytosis requires positioning of damaged mitochondria at the cell periphery, which occurs because damaged mitochondria avoid binding to inward motor proteins. Functionally, mitocytosis plays an important role in maintaining mitochondrial quality. Enhanced mitocytosis protects cells from mitochondrial stressor-induced loss of mitochondrial membrane potential (MMP) and mitochondrial respiration; conversely, blocking mitocytosis causes loss of MMP and mitochondrial respiration under normal conditions. Physiologically, we demonstrate that mitocytosis is required for maintaining MMP and viability in neutrophils in vivo. We propose that mitocytosis is an important mitochondrial quality-control process in migrating cells, which couples mitochondrial homeostasis with cell migration.
Asunto(s)
Potencial de la Membrana Mitocondrial/fisiología , Mitocondrias/metabolismo , Animales , Transporte Biológico , Línea Celular , Movimiento Celular/fisiología , Citoplasma/metabolismo , Exocitosis/fisiología , Femenino , Homeostasis , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía Electrónica de Transmisión/métodos , Mitocondrias/fisiología , Membranas Mitocondriales/metabolismo , Orgánulos/metabolismoRESUMEN
Long-term subcellular intravital imaging in mammals is vital to study diverse intercellular behaviors and organelle functions during native physiological processes. However, optical heterogeneity, tissue opacity, and phototoxicity pose great challenges. Here, we propose a computational imaging framework, termed digital adaptive optics scanning light-field mutual iterative tomography (DAOSLIMIT), featuring high-speed, high-resolution 3D imaging, tiled wavefront correction, and low phototoxicity with a compact system. By tomographic imaging of the entire volume simultaneously, we obtained volumetric imaging across 225 × 225 × 16 µm3, with a resolution of up to 220 nm laterally and 400 nm axially, at the millisecond scale, over hundreds of thousands of time points. To establish the capabilities, we investigated large-scale cell migration and neural activities in different species and observed various subcellular dynamics in mammals during neutrophil migration and tumor cell circulation.
Asunto(s)
Algoritmos , Imagenología Tridimensional , Óptica y Fotónica , Tomografía , Animales , Calcio/metabolismo , Línea Celular Tumoral , Membrana Celular/metabolismo , Movimiento Celular , Drosophila , Células HeLa , Humanos , Larva/fisiología , Hígado/diagnóstico por imagen , Masculino , Ratones Endogámicos C57BL , Neoplasias/patología , Ratas Sprague-Dawley , Relación Señal-Ruido , Fracciones Subcelulares/fisiología , Factores de Tiempo , Pez CebraRESUMEN
Many embryonic organs undergo epithelial morphogenesis to form tree-like hierarchical structures. However, it remains unclear what drives the budding and branching of stratified epithelia, such as in the embryonic salivary gland and pancreas. Here, we performed live-organ imaging of mouse embryonic salivary glands at single-cell resolution to reveal that budding morphogenesis is driven by expansion and folding of a distinct epithelial surface cell sheet characterized by strong cell-matrix adhesions and weak cell-cell adhesions. Profiling of single-cell transcriptomes of this epithelium revealed spatial patterns of transcription underlying these cell adhesion differences. We then synthetically reconstituted budding morphogenesis by experimentally suppressing E-cadherin expression and inducing basement membrane formation in 3D spheroid cultures of engineered cells, which required ß1-integrin-mediated cell-matrix adhesion for successful budding. Thus, stratified epithelial budding, the key first step of branching morphogenesis, is driven by an overall combination of strong cell-matrix adhesion and weak cell-cell adhesion by peripheral epithelial cells.
Asunto(s)
Uniones Célula-Matriz/metabolismo , Morfogénesis , Animales , Membrana Basal/metabolismo , Adhesión Celular , División Celular , Movimiento Celular , Rastreo Celular , Embrión de Mamíferos/citología , Células Epiteliales/citología , Células Epiteliales/metabolismo , Epitelio , Regulación del Desarrollo de la Expresión Génica , Células HEK293 , Humanos , Integrinas/metabolismo , Ratones , Modelos Biológicos , Glándulas Salivales/citología , Glándulas Salivales/embriología , Glándulas Salivales/metabolismo , Transcriptoma/genéticaRESUMEN
Cytotoxic T lymphocyte (CTL) responses against tumors are maintained by stem-like memory cells that self-renew but also give rise to effector-like cells. The latter gradually lose their anti-tumor activity and acquire an epigenetically fixed, hypofunctional state, leading to tumor tolerance. Here, we show that the conversion of stem-like into effector-like CTLs involves a major chemotactic reprogramming that includes the upregulation of chemokine receptor CXCR6. This receptor positions effector-like CTLs in a discrete perivascular niche of the tumor stroma that is densely occupied by CCR7+ dendritic cells (DCs) expressing the CXCR6 ligand CXCL16. CCR7+ DCs also express and trans-present the survival cytokine interleukin-15 (IL-15). CXCR6 expression and IL-15 trans-presentation are critical for the survival and local expansion of effector-like CTLs in the tumor microenvironment to maximize their anti-tumor activity before progressing to irreversible dysfunction. These observations reveal a cellular and molecular checkpoint that determines the magnitude and outcome of anti-tumor immune responses.
Asunto(s)
Receptores CXCR6/metabolismo , Linfocitos T Citotóxicos/inmunología , Microambiente Tumoral , Animales , Antígeno B7-H1/metabolismo , Comunicación Celular , Movimiento Celular , Proliferación Celular , Supervivencia Celular , Quimiocina CXCL16 , Células Dendríticas/metabolismo , Interleucina-12/metabolismo , Interleucina-15/metabolismo , Ligandos , Ganglios Linfáticos/metabolismo , Melanoma/inmunología , Melanoma/patología , Ratones Endogámicos C57BLRESUMEN
While intestinal Th17 cells are critical for maintaining tissue homeostasis, recent studies have implicated their roles in the development of extra-intestinal autoimmune diseases including multiple sclerosis. However, the mechanisms by which tissue Th17 cells mediate these dichotomous functions remain unknown. Here, we characterized the heterogeneity, plasticity, and migratory phenotypes of tissue Th17 cells in vivo by combined fate mapping with profiling of the transcriptomes and TCR clonotypes of over 84,000 Th17 cells at homeostasis and during CNS autoimmune inflammation. Inter- and intra-organ single-cell analyses revealed a homeostatic, stem-like TCF1+ IL-17+ SLAMF6+ population that traffics to the intestine where it is maintained by the microbiota, providing a ready reservoir for the IL-23-driven generation of encephalitogenic GM-CSF+ IFN-γ+ CXCR6+ T cells. Our study defines a direct in vivo relationship between IL-17+ non-pathogenic and GM-CSF+ and IFN-γ+ pathogenic Th17 populations and provides a mechanism by which homeostatic intestinal Th17 cells direct extra-intestinal autoimmune disease.
Asunto(s)
Autoinmunidad , Intestinos/inmunología , Células Madre/metabolismo , Células Th17/inmunología , Animales , Movimiento Celular , Células Clonales , Encefalomielitis Autoinmune Experimental/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Homeostasis , Humanos , Interferón gamma/metabolismo , Interleucina-17/metabolismo , Ratones Endogámicos C57BL , Especificidad de Órganos , ARN/metabolismo , RNA-Seq , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores CXCR6/metabolismo , Receptores de Interleucina/metabolismo , Reproducibilidad de los Resultados , Familia de Moléculas Señalizadoras de la Activación Linfocitaria/metabolismo , Análisis de la Célula Individual , Bazo/metabolismoRESUMEN
During cell migration or differentiation, cell surface receptors are simultaneously exposed to different ligands. However, it is often unclear how these extracellular signals are integrated. Neogenin (NEO1) acts as an attractive guidance receptor when the Netrin-1 (NET1) ligand binds, but it mediates repulsion via repulsive guidance molecule (RGM) ligands. Here, we show that signal integration occurs through the formation of a ternary NEO1-NET1-RGM complex, which triggers reciprocal silencing of downstream signaling. Our NEO1-NET1-RGM structures reveal a "trimer-of-trimers" super-assembly, which exists in the cell membrane. Super-assembly formation results in inhibition of RGMA-NEO1-mediated growth cone collapse and RGMA- or NET1-NEO1-mediated neuron migration, by preventing formation of signaling-compatible RGM-NEO1 complexes and NET1-induced NEO1 ectodomain clustering. These results illustrate how simultaneous binding of ligands with opposing functions, to a single receptor, does not lead to competition for binding, but to formation of a super-complex that diminishes their functional outputs.
Asunto(s)
Moléculas de Adhesión Celular Neuronal/metabolismo , Proteínas Ligadas a GPI/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Proteínas Oncogénicas/metabolismo , Animales , Moléculas de Adhesión Celular Neuronal/química , Movimiento Celular , Receptor DCC/deficiencia , Receptor DCC/genética , Proteínas Ligadas a GPI/química , Conos de Crecimiento/fisiología , Humanos , Ventrículos Laterales/citología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Proteínas del Tejido Nervioso/química , Neuronas/citología , Neuronas/metabolismo , Proteínas Oncogénicas/química , Proteínas Oncogénicas/genética , Unión Proteica , Multimerización de Proteína , Estructura Cuaternaria de Proteína , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Transducción de SeñalRESUMEN
Cross-presentation of antigens from dead tumor cells by type 1 conventional dendritic cells (cDC1s) is thought to underlie priming of anti-cancer CD8+ T cells. cDC1 express high levels of DNGR-1 (a.k.a. CLEC9A), a receptor that binds to F-actin exposed by dead cell debris and promotes cross-presentation of associated antigens. Here, we show that secreted gelsolin (sGSN), an extracellular protein, decreases DNGR-1 binding to F-actin and cross-presentation of dead cell-associated antigens by cDC1s. Mice deficient in sGsn display increased DNGR-1-dependent resistance to transplantable tumors, especially ones expressing neoantigens associated with the actin cytoskeleton, and exhibit greater responsiveness to cancer immunotherapy. In human cancers, lower levels of intratumoral sGSN transcripts, as well as presence of mutations in proteins associated with the actin cytoskeleton, are associated with signatures of anti-cancer immunity and increased patient survival. Our results reveal a natural barrier to cross-presentation of cancer antigens that dampens anti-tumor CD8+ T cell responses.