RESUMEN
The choice of developing thymocytes to become CD8+ cytotoxic or CD4+ helper T cells has been intensely studied, but many of the underlying mechanisms remain to be elucidated. Recent multiomics approaches have provided much higher resolution analysis of gene expression in developing thymocytes than was previously achievable, thereby offering a fresh perspective on this question. Focusing on our recent studies using CITE-seq (cellular indexing of transcriptomes and epitopes) analyses of mouse thymocytes, we present a detailed timeline of RNA and protein expression changes during CD8 versus CD4 T cell differentiation. We also revisit our current understanding of the links between T cell receptor signaling and expression of the lineage-defining transcription factors ThPOK and RUNX3. Finally, we propose a sequential selection model to explain the tight linkage between MHC-I versus MHC-II recognition and T cell lineage choice. This model incorporates key aspects of previously proposed kinetic signaling, instructive, and stochastic/selection models.
Asunto(s)
Linfocitos T CD4-Positivos , Linfocitos T CD8-positivos , Diferenciación Celular , Linaje de la Célula , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Humanos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Subunidad alfa 3 del Factor de Unión al Sitio Principal/metabolismo , Subunidad alfa 3 del Factor de Unión al Sitio Principal/genética , Ratones , Factores de Transcripción/metabolismo , Transcriptoma , MultiómicaRESUMEN
Taurine is used to bolster immunity, but its effects on antitumor immunity are unclear. Here, we report that cancer-related taurine consumption causes T cell exhaustion and tumor progression. The taurine transporter SLC6A6 is correlated with aggressiveness and poor outcomes in multiple cancers. SLC6A6-mediated taurine uptake promotes the malignant behaviors of tumor cells but also increases the survival and effector function of CD8+ T cells. Tumor cells outcompete CD8+ T cells for taurine by overexpressing SLC6A6, which induces T cell death and malfunction, thereby fueling tumor progression. Mechanistically, taurine deficiency in CD8+ T cells increases ER stress, promoting ATF4 transcription in a PERK-JAK1-STAT3 signaling-dependent manner. Increased ATF4 transactivates multiple immune checkpoint genes and induces T cell exhaustion. In gastric cancer, we identify a chemotherapy-induced SP1-SLC6A6 regulatory axis. Our findings suggest that tumoral-SLC6A6-mediated taurine deficiency promotes immune evasion and that taurine supplementation reinvigorates exhausted CD8+ T cells and increases the efficacy of cancer therapies.
Asunto(s)
Linfocitos T CD8-positivos , Glicoproteínas de Membrana , Taurina , Taurina/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Animales , Humanos , Ratones , Línea Celular Tumoral , Ratones Endogámicos C57BL , Estrés del Retículo Endoplásmico , Factor de Transcripción Activador 4/metabolismo , Transducción de Señal , Femenino , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Transporte de Membrana/genética , Factor de Transcripción STAT3/metabolismoRESUMEN
Reversing CD8+ T cell dysfunction is crucial in treating chronic hepatitis B virus (HBV) infection, yet specific molecular targets remain unclear. Our study analyzed co-signaling receptors during hepatocellular priming and traced the trajectory and fate of dysfunctional HBV-specific CD8+ T cells. Early on, these cells upregulate PD-1, CTLA-4, LAG-3, OX40, 4-1BB, and ICOS. While blocking co-inhibitory receptors had minimal effect, activating 4-1BB and OX40 converted them into antiviral effectors. Prolonged stimulation led to a self-renewing, long-lived, heterogeneous population with a unique transcriptional profile. This includes dysfunctional progenitor/stem-like (TSL) cells and two distinct dysfunctional tissue-resident memory (TRM) populations. While 4-1BB expression is ubiquitously maintained, OX40 expression is limited to TSL. In chronic settings, only 4-1BB stimulation conferred antiviral activity. In HBeAg+ chronic patients, 4-1BB activation showed the highest potential to rejuvenate dysfunctional CD8+ T cells. Targeting all dysfunctional T cells, rather than only stem-like precursors, holds promise for treating chronic HBV infection.
Asunto(s)
Linfocitos T CD8-positivos , Virus de la Hepatitis B , Hepatitis B Crónica , Humanos , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/virología , Hepatitis B Crónica/metabolismo , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Transducción de Señal , Animales , Receptores OX40/metabolismo , Ratones , Receptor de Muerte Celular Programada 1/metabolismo , Antígenos CD/metabolismoRESUMEN
Alterations in extracellular matrix (ECM) architecture and stiffness represent hallmarks of cancer. Whether the biomechanical property of ECM impacts the functionality of tumor-reactive CD8+ T cells remains largely unknown. Here, we reveal that the transcription factor (TF) Osr2 integrates biomechanical signaling and facilitates the terminal exhaustion of tumor-reactive CD8+ T cells. Osr2 expression is selectively induced in the terminally exhausted tumor-specific CD8+ T cell subset by coupled T cell receptor (TCR) signaling and biomechanical stress mediated by the Piezo1/calcium/CREB axis. Consistently, depletion of Osr2 alleviates the exhaustion of tumor-specific CD8+ T cells or CAR-T cells, whereas forced Osr2 expression aggravates their exhaustion in solid tumor models. Mechanistically, Osr2 recruits HDAC3 to rewire the epigenetic program for suppressing cytotoxic gene expression and promoting CD8+ T cell exhaustion. Thus, our results unravel Osr2 functions as a biomechanical checkpoint to exacerbate CD8+ T cell exhaustion and could be targeted to potentiate cancer immunotherapy.
Asunto(s)
Linfocitos T CD8-positivos , Factores de Transcripción , Animales , Femenino , Humanos , Ratones , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Línea Celular Tumoral , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Matriz Extracelular/metabolismo , Histona Desacetilasas/metabolismo , Ratones Endogámicos C57BL , Neoplasias/inmunología , Neoplasias/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Agotamiento de Células T , Factores de Transcripción/metabolismo , Microambiente Tumoral , Estrés MecánicoRESUMEN
Overcoming immune-mediated resistance to PD-1 blockade remains a major clinical challenge. Enhanced efficacy has been demonstrated in melanoma patients with combined nivolumab (anti-PD-1) and relatlimab (anti-LAG-3) treatment, the first in its class to be FDA approved. However, how these two inhibitory receptors synergize to hinder anti-tumor immunity remains unknown. Here, we show that CD8+ T cells deficient in both PD-1 and LAG-3, in contrast to CD8+ T cells lacking either receptor, mediate enhanced tumor clearance and long-term survival in mouse models of melanoma. PD-1- and LAG-3-deficient CD8+ T cells were transcriptionally distinct, with broad TCR clonality and enrichment of effector-like and interferon-responsive genes, resulting in enhanced IFN-γ release indicative of functionality. LAG-3 and PD-1 combined to drive T cell exhaustion, playing a dominant role in modulating TOX expression. Mechanistically, autocrine, cell-intrinsic IFN-γ signaling was required for PD-1- and LAG-3-deficient CD8+ T cells to enhance anti-tumor immunity, providing insight into how combinatorial targeting of LAG-3 and PD-1 enhances efficacy.
Asunto(s)
Antígenos CD , Linfocitos T CD8-positivos , Interferón gamma , Proteína del Gen 3 de Activación de Linfocitos , Ratones Endogámicos C57BL , Receptor de Muerte Celular Programada 1 , Receptor de Muerte Celular Programada 1/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Animales , Interferón gamma/metabolismo , Ratones , Antígenos CD/metabolismo , Comunicación Autocrina , Humanos , Melanoma/inmunología , Melanoma/tratamiento farmacológico , Femenino , Línea Celular Tumoral , Melanoma Experimental/inmunología , Agotamiento de Células TRESUMEN
Clinical trials have identified ARID1A mutations as enriched among patients who respond favorably to immune checkpoint blockade (ICB) in several solid tumor types independent of microsatellite instability. We show that ARID1A loss in murine models is sufficient to induce anti-tumor immune phenotypes observed in ARID1A mutant human cancers, including increased CD8+ T cell infiltration and cytolytic activity. ARID1A-deficient cancers upregulated an interferon (IFN) gene expression signature, the ARID1A-IFN signature, associated with increased R-loops and cytosolic single-stranded DNA (ssDNA). Overexpression of the R-loop resolving enzyme, RNASEH2B, or cytosolic DNase, TREX1, in ARID1A-deficient cells prevented cytosolic ssDNA accumulation and ARID1A-IFN gene upregulation. Further, the ARID1A-IFN signature and anti-tumor immunity were driven by STING-dependent type I IFN signaling, which was required for improved responsiveness of ARID1A mutant tumors to ICB treatment. These findings define a molecular mechanism underlying anti-tumor immunity in ARID1A mutant cancers.
Asunto(s)
Linfocitos T CD8-positivos , Proteínas de Unión al ADN , Interferón Tipo I , Proteínas de la Membrana , Neoplasias , Transducción de Señal , Factores de Transcripción , Animales , Humanos , Ratones , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Línea Celular Tumoral , Proteínas de Unión al ADN/metabolismo , Exodesoxirribonucleasas/metabolismo , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Interferón Tipo I/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Ratones Endogámicos C57BL , Mutación , Neoplasias/inmunología , Neoplasias/genética , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Factores de Transcripción/metabolismo , Masculino , Quimiocinas/genética , Quimiocinas/metabolismoRESUMEN
Exhausted CD8 T (Tex) cells in chronic viral infection and cancer have sustained co-expression of inhibitory receptors (IRs). Tex cells can be reinvigorated by blocking IRs, such as PD-1, but synergistic reinvigoration and enhanced disease control can be achieved by co-targeting multiple IRs including PD-1 and LAG-3. To dissect the molecular changes intrinsic when these IR pathways are disrupted, we investigated the impact of loss of PD-1 and/or LAG-3 on Tex cells during chronic infection. These analyses revealed distinct roles of PD-1 and LAG-3 in regulating Tex cell proliferation and effector functions, respectively. Moreover, these studies identified an essential role for LAG-3 in sustaining TOX and Tex cell durability as well as a LAG-3-dependent circuit that generated a CD94/NKG2+ subset of Tex cells with enhanced cytotoxicity mediated by recognition of the stress ligand Qa-1b, with similar observations in humans. These analyses disentangle the non-redundant mechanisms of PD-1 and LAG-3 and their synergy in regulating Tex cells.
Asunto(s)
Antígenos CD , Linfocitos T CD8-positivos , Antígenos de Histocompatibilidad Clase I , Proteína del Gen 3 de Activación de Linfocitos , Subfamília D de Receptores Similares a Lectina de las Células NK , Receptor de Muerte Celular Programada 1 , Animales , Antígenos CD/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Ratones , Receptor de Muerte Celular Programada 1/metabolismo , Subfamília D de Receptores Similares a Lectina de las Células NK/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Subfamília C de Receptores Similares a Lectina de Células NK/metabolismo , Ratones Endogámicos C57BL , Proteínas del Grupo de Alta Movilidad/metabolismo , Proteínas del Grupo de Alta Movilidad/genética , Citotoxicidad Inmunológica , Proliferación Celular , Células Asesinas Naturales/metabolismo , Células Asesinas Naturales/inmunologíaRESUMEN
Relatlimab (rela; anti-LAG-3) plus nivolumab (nivo; anti-PD-1) is safe and effective for treatment of advanced melanoma. We designed a trial (NCT03743766) where advanced melanoma patients received rela, nivo, or rela+nivo to interrogate the immunologic mechanisms of rela+nivo. Analysis of biospecimens from this ongoing trial demonstrated that rela+nivo led to enhanced capacity for CD8+ T cell receptor signaling and altered CD8+ T cell differentiation, leading to heightened cytotoxicity despite the retention of an exhaustion profile. Co-expression of cytotoxic and exhaustion signatures was driven by PRDM1, BATF, ETV7, and TOX. Effector function was upregulated in clonally expanded CD8+ T cells that emerged after rela+nivo. A rela+nivo intratumoral CD8+ T cell signature was associated with a favorable prognosis. This intratumoral rela+nivo signature was validated in peripheral blood as an elevated frequency of CD38+TIM3+CD8+ T cells. Overall, we demonstrated that cytotoxicity can be enhanced despite the retention of exhaustion signatures, which will inform future therapeutic strategies.
Asunto(s)
Linfocitos T CD8-positivos , Proteína del Gen 3 de Activación de Linfocitos , Melanoma , Receptor de Muerte Celular Programada 1 , Humanos , Antígenos CD/metabolismo , Antígenos CD/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Diferenciación Celular , Citotoxicidad Inmunológica , Proteínas del Grupo de Alta Movilidad , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/farmacología , Proteína del Gen 3 de Activación de Linfocitos/antagonistas & inhibidores , Melanoma/inmunología , Melanoma/tratamiento farmacológico , Melanoma/genética , Nivolumab/uso terapéutico , Nivolumab/farmacología , Factor 1 de Unión al Dominio 1 de Regulación Positiva/metabolismo , Factor 1 de Unión al Dominio 1 de Regulación Positiva/genética , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Transducción de SeñalRESUMEN
Post-acute sequelae of COVID-19 (PASC) represent an emerging global crisis. However, quantifiable risk factors for PASC and their biological associations are poorly resolved. We executed a deep multi-omic, longitudinal investigation of 309 COVID-19 patients from initial diagnosis to convalescence (2-3 months later), integrated with clinical data and patient-reported symptoms. We resolved four PASC-anticipating risk factors at the time of initial COVID-19 diagnosis: type 2 diabetes, SARS-CoV-2 RNAemia, Epstein-Barr virus viremia, and specific auto-antibodies. In patients with gastrointestinal PASC, SARS-CoV-2-specific and CMV-specific CD8+ T cells exhibited unique dynamics during recovery from COVID-19. Analysis of symptom-associated immunological signatures revealed coordinated immunity polarization into four endotypes, exhibiting divergent acute severity and PASC. We find that immunological associations between PASC factors diminish over time, leading to distinct convalescent immune states. Detectability of most PASC factors at COVID-19 diagnosis emphasizes the importance of early disease measurements for understanding emergent chronic conditions and suggests PASC treatment strategies.
Asunto(s)
COVID-19/complicaciones , COVID-19/diagnóstico , Convalecencia , Inmunidad Adaptativa/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Autoanticuerpos/sangre , Biomarcadores/metabolismo , Proteínas Sanguíneas/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , COVID-19/inmunología , COVID-19/patología , COVID-19/virología , Progresión de la Enfermedad , Femenino , Humanos , Inmunidad Innata/genética , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Factores de Riesgo , SARS-CoV-2/aislamiento & purificación , Transcriptoma , Adulto Joven , Síndrome Post Agudo de COVID-19RESUMEN
We address whether T cell responses induced by different vaccine platforms (mRNA-1273, BNT162b2, Ad26.COV2.S, and NVX-CoV2373) cross-recognize early SARS-CoV-2 variants. T cell responses to early variants were preserved across vaccine platforms. By contrast, significant overall decreases were observed for memory B cells and neutralizing antibodies. In subjects â¼6 months post-vaccination, 90% (CD4+) and 87% (CD8+) of memory T cell responses were preserved against variants on average by AIM assay, and 84% (CD4+) and 85% (CD8+) preserved against Omicron. Omicron RBD memory B cell recognition was substantially reduced to 42% compared with other variants. T cell epitope repertoire analysis revealed a median of 11 and 10 spike epitopes recognized by CD4+ and CD8+ T cells, with average preservation > 80% for Omicron. Functional preservation of the majority of T cell responses may play an important role as a second-level defense against diverse variants.
Asunto(s)
Vacunas contra la COVID-19/inmunología , Células B de Memoria/inmunología , Células T de Memoria/inmunología , SARS-CoV-2/inmunología , Ad26COVS1/administración & dosificación , Ad26COVS1/inmunología , Vacuna BNT162/administración & dosificación , Vacuna BNT162/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , COVID-19/patología , COVID-19/prevención & control , COVID-19/virología , Vacunas contra la COVID-19/administración & dosificación , Epítopos/inmunología , Epítopos de Linfocito T/inmunología , Humanos , Células B de Memoria/metabolismo , Células T de Memoria/metabolismo , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/inmunología , VacunaciónRESUMEN
Immune cells need to sustain a state of constant alertness over a lifetime. Yet, little is known about the regulatory processes that control the fluent and fragile balance that is called homeostasis. Here we demonstrate that JAK-STAT signaling, beyond its role in immune responses, is a major regulator of immune cell homeostasis. We investigated JAK-STAT-mediated transcription and chromatin accessibility across 12 mouse models, including knockouts of all STAT transcription factors and of the TYK2 kinase. Baseline JAK-STAT signaling was detected in CD8+ T cells and macrophages of unperturbed mice-but abrogated in the knockouts and in unstimulated immune cells deprived of their normal tissue context. We observed diverse gene-regulatory programs, including effects of STAT2 and IRF9 that were independent of STAT1. In summary, our large-scale dataset and integrative analysis of JAK-STAT mutant and wild-type mice uncovered a crucial role of JAK-STAT signaling in unstimulated immune cells, where it contributes to a poised epigenetic and transcriptional state and helps prepare these cells for rapid response to immune stimuli.
Asunto(s)
Homeostasis , Quinasas Janus , Macrófagos , Ratones Noqueados , Factores de Transcripción STAT , Transducción de Señal , Animales , Ratones , Macrófagos/inmunología , Macrófagos/metabolismo , Quinasas Janus/metabolismo , Factores de Transcripción STAT/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT1/genética , Ratones Endogámicos C57BL , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/metabolismo , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/genética , TYK2 Quinasa/metabolismo , TYK2 Quinasa/genética , Regulación de la Expresión GénicaRESUMEN
T cell infiltration into tumors is a favorable prognostic feature, but most solid tumors lack productive T cell responses. Mechanisms that coordinate T cell exclusion are incompletely understood. Here we identify hepatocyte activation via interleukin-6/STAT3 and secretion of serum amyloid A (SAA) proteins 1 and 2 as important regulators of T cell surveillance of extrahepatic tumors. Loss of STAT3 in hepatocytes or SAA remodeled the tumor microenvironment with infiltration by CD8+ T cells, while interleukin-6 overexpression in hepatocytes and SAA signaling via Toll-like receptor 2 reduced the number of intratumoral dendritic cells and, in doing so, inhibited T cell tumor infiltration. Genetic ablation of SAA enhanced survival after tumor resection in a T cell-dependent manner. Likewise, in individuals with pancreatic ductal adenocarcinoma, long-term survivors after surgery demonstrated lower serum SAA levels than short-term survivors. Taken together, these data define a fundamental link between liver and tumor immunobiology wherein hepatocytes govern productive T cell surveillance in cancer.
Asunto(s)
Linfocitos T CD8-positivos , Hepatocitos , Interleucina-6 , Factor de Transcripción STAT3 , Proteína Amiloide A Sérica , Proteína Amiloide A Sérica/metabolismo , Proteína Amiloide A Sérica/genética , Hepatocitos/metabolismo , Hepatocitos/inmunología , Animales , Humanos , Ratones , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Interleucina-6/metabolismo , Factor de Transcripción STAT3/metabolismo , Microambiente Tumoral/inmunología , Ratones Endogámicos C57BL , Ratones Noqueados , Escape del Tumor , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Neoplasias Pancreáticas/inmunología , Neoplasias Pancreáticas/metabolismo , Transducción de Señal , Carcinoma Ductal Pancreático/inmunología , Carcinoma Ductal Pancreático/patología , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Línea Celular TumoralRESUMEN
Improving effector activity of antigen-specific T cells is a major goal in cancer immunotherapy. Despite the identification of several effector T cell (TEFF)-driving transcription factors (TFs), the transcriptional coordination of TEFF biology remains poorly understood. We developed an in vivo T cell CRISPR screening platform and identified a key mechanism restraining TEFF biology through the ETS family TF, Fli1. Genetic deletion of Fli1 enhanced TEFF responses without compromising memory or exhaustion precursors. Fli1 restrained TEFF lineage differentiation by binding to cis-regulatory elements of effector-associated genes. Loss of Fli1 increased chromatin accessibility at ETS:RUNX motifs, allowing more efficient Runx3-driven TEFF biology. CD8+ T cells lacking Fli1 provided substantially better protection against multiple infections and tumors. These data indicate that Fli1 safeguards the developing CD8+ T cell transcriptional landscape from excessive ETS:RUNX-driven TEFF cell differentiation. Moreover, genetic deletion of Fli1 improves TEFF differentiation and protective immunity in infections and cancer.
Asunto(s)
Linfocitos T CD8-positivos/citología , Proteína Proto-Oncogénica c-fli-1/metabolismo , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Sistemas CRISPR-Cas , Diferenciación Celular , Enfermedad Crónica , Subunidad alfa 3 del Factor de Unión al Sitio Principal/metabolismo , Epigénesis Genética , Redes Reguladoras de Genes , Infecciones/inmunología , Ratones , Neoplasias/inmunologíaRESUMEN
Amino acid metabolism is essential for cell survival, while the byproduct ammonia is toxic and can injure cellular longevity. Here we show that CD8+ memory T (TM) cells mobilize the carbamoyl phosphate (CP) metabolic pathway to clear ammonia, thus promoting memory development. CD8+ TM cells use ß-hydroxybutyrylation to upregulate CP synthetase 1 and trigger the CP metabolic cascade to form arginine in the cytosol. This cytosolic arginine is then translocated into the mitochondria where it is split by arginase 2 to urea and ornithine. Cytosolic arginine is also converted to nitric oxide and citrulline by nitric oxide synthases. Thus, both the urea and citrulline cycles are employed by CD8+ T cells to clear ammonia and enable memory development. This ammonia clearance machinery might be targeted to improve T cell-based cancer immunotherapies.
Asunto(s)
Amoníaco , Citrulina , Citrulina/metabolismo , Amoníaco/metabolismo , Urea/metabolismo , Linfocitos T CD8-positivos/metabolismo , Óxido Nítrico , Arginina/metabolismo , Arginasa/metabolismoRESUMEN
How lipidome changes support CD8+ effector T (Teff) cell differentiation is not well understood. Here we show that, although naive T cells are rich in polyunsaturated phosphoinositides (PIPn with 3-4 double bonds), Teff cells have unique PIPn marked by saturated fatty acyl chains (0-2 double bonds). PIPn are precursors for second messengers. Polyunsaturated phosphatidylinositol bisphosphate (PIP2) exclusively supported signaling immediately upon T cell antigen receptor activation. In late Teff cells, activity of phospholipase C-γ1, the enzyme that cleaves PIP2 into downstream mediators, waned, and saturated PIPn became essential for sustained signaling. Saturated PIP was more rapidly converted to PIP2 with subsequent recruitment of phospholipase C-γ1, and loss of saturated PIPn impaired Teff cell fitness and function, even in cells with abundant polyunsaturated PIPn. Glucose was the substrate for de novo PIPn synthesis, and was rapidly utilized for saturated PIP2 generation. Thus, separate PIPn pools with distinct acyl chain compositions and metabolic dependencies drive important signaling events to initiate and then sustain effector function during CD8+ T cell differentiation.
Asunto(s)
Fosfatos de Fosfatidilinositol , Fosfatidilinositoles , Fosfatidilinositoles/metabolismo , Transducción de Señal , Fosfolipasas de Tipo C/metabolismo , Linfocitos T CD8-positivos/metabolismoRESUMEN
Co-inhibitory and checkpoint molecules suppress T cell function in the tumor microenvironment, thereby rendering T cells dysfunctional. Although immune checkpoint blockade is a successful treatment option for multiple human cancers, severe autoimmune-like adverse effects can limit its application. Here, we show that the gene encoding peptidoglycan recognition protein 1 (PGLYRP1) is highly coexpressed with genes encoding co-inhibitory molecules, indicating that it might be a promising target for cancer immunotherapy. Genetic deletion of Pglyrp1 in mice led to decreased tumor growth and an increased activation/effector phenotype in CD8+ T cells, suggesting an inhibitory function of PGLYRP1 in CD8+ T cells. Surprisingly, genetic deletion of Pglyrp1 protected against the development of experimental autoimmune encephalomyelitis, a model of autoimmune disease in the central nervous system. PGLYRP1-deficient myeloid cells had a defect in antigen presentation and T cell activation, indicating that PGLYRP1 might function as a proinflammatory molecule in myeloid cells during autoimmunity. These results highlight PGLYRP1 as a promising target for immunotherapy that, when targeted, elicits a potent antitumor immune response while protecting against some forms of tissue inflammation and autoimmunity.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Neoplasias , Animales , Humanos , Ratones , Linfocitos T CD8-positivos/metabolismo , Citocinas/metabolismo , Encefalomielitis Autoinmune Experimental/genética , Inmunoterapia , Inflamación , Enfermedades Neuroinflamatorias , Microambiente TumoralRESUMEN
Gamma delta (γδ) T cells reside within human tissues including tumors, but their function in mediating antitumor responses to immune checkpoint inhibition is unknown. Here we show that kidney cancers are infiltrated by Vδ2- γδ T cells, with equivalent representation of Vδ1+ and Vδ1- cells, that are distinct from γδ T cells found in normal human tissues. These tumor-resident Vδ2- T cells can express the transcriptional program of exhausted αß CD8+ T cells as well as canonical markers of terminal T-cell exhaustion including PD-1, TIGIT and TIM-3. Although Vδ2- γδ T cells have reduced IL-2 production, they retain expression of cytolytic effector molecules and co-stimulatory receptors such as 4-1BB. Exhausted Vδ2- γδ T cells are composed of three distinct populations that lack TCF7, are clonally expanded and express cytotoxic molecules and multiple Vδ2- T-cell receptors. Human tumor-derived Vδ2- γδ T cells maintain cytotoxic function and pro-inflammatory cytokine secretion in vitro. The transcriptional program of Vδ2- T cells in pretreatment tumor biopsies was used to predict subsequent clinical responses to PD-1 blockade in patients with cancer. Thus, Vδ2- γδ T cells within the tumor microenvironment can contribute to antitumor efficacy.
Asunto(s)
Linfocitos T CD8-positivos , Neoplasias Renales , Humanos , Linfocitos T CD8-positivos/metabolismo , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Receptor de Muerte Celular Programada 1/metabolismo , Neoplasias Renales/metabolismo , Subgrupos de Linfocitos T , Microambiente TumoralRESUMEN
The malate shuttle is traditionally understood to maintain NAD+/NADH balance between the cytosol and mitochondria. Whether the malate shuttle has additional functions is unclear. Here we show that chronic viral infections induce CD8+ T cell expression of GOT1, a central enzyme in the malate shuttle. Got1 deficiency decreased the NAD+/NADH ratio and limited antiviral CD8+ T cell responses to chronic infection; however, increasing the NAD+/NADH ratio did not restore T cell responses. Got1 deficiency reduced the production of the ammonia scavenger 2-ketoglutarate (2-KG) from glutaminolysis and led to a toxic accumulation of ammonia in CD8+ T cells. Supplementation with 2-KG assimilated and detoxified ammonia in Got1-deficient T cells and restored antiviral responses. These data indicate that the major function of the malate shuttle in CD8+ T cells is not to maintain the NAD+/NADH balance but rather to detoxify ammonia and enable sustainable ammonia-neutral glutamine catabolism in CD8+ T cells during chronic infection.
Asunto(s)
Ácidos Cetoglutáricos , NAD , Humanos , Oxidación-Reducción , NAD/metabolismo , Ácidos Cetoglutáricos/metabolismo , Amoníaco , Malatos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Infección Persistente , AntiviralesRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA generally becomes undetectable in upper airways after a few days or weeks postinfection. Here we used a model of viral infection in macaques to address whether SARS-CoV-2 persists in the body and which mechanisms regulate its persistence. Replication-competent virus was detected in bronchioalveolar lavage (BAL) macrophages beyond 6 months postinfection. Viral propagation in BAL macrophages occurred from cell to cell and was inhibited by interferon-γ (IFN-γ). IFN-γ production was strongest in BAL NKG2r+CD8+ T cells and NKG2Alo natural killer (NK) cells and was further increased in NKG2Alo NK cells after spike protein stimulation. However, IFN-γ production was impaired in NK cells from macaques with persisting virus. Moreover, IFN-γ also enhanced the expression of major histocompatibility complex (MHC)-E on BAL macrophages, possibly inhibiting NK cell-mediated killing. Macaques with less persisting virus mounted adaptive NK cells that escaped the MHC-E-dependent inhibition. Our findings reveal an interplay between NK cells and macrophages that regulated SARS-CoV-2 persistence in macrophages and was mediated by IFN-γ.
Asunto(s)
COVID-19 , Interferón gamma , Animales , Interferón gamma/metabolismo , SARS-CoV-2/metabolismo , Linfocitos T CD8-positivos/metabolismo , Macrófagos Alveolares/metabolismo , Células Asesinas Naturales/metabolismo , Pulmón/metabolismo , Macaca/metabolismoRESUMEN
The generation of the TCRαß lineage of T cells occurs in the thymus through a series of orchestrated developmental events that result in a carefully selected population of CD4 or CD8 lineage-committed TCR(+) thymocytes capable of recognizing foreign antigen in the context of self MHC. T cells first exit the thymus in a phenotypically and functionally immature state and require an approximately 3-week period of post-thymic maturation before transitioning into the mature T cell compartment. A greater understanding of recent thymic emigrant biology has come with the development of methods to exclusively identify and isolate this population for further characterization. I now review current knowledge about the phenotype and function of this key but understudied population of peripheral T cells.