RESUMO
Downward social mobility is a well-known mental risk factor for depression, but its neural mechanism remains elusive. Here, by forcing mice to lose against their subordinates in a non-violent social contest, we lower their social ranks stably and induce depressive-like behaviors. These rank-decline-associated depressive-like behaviors can be reversed by regaining social status. In vivo fiber photometry and single-unit electrophysiological recording show that forced loss, but not natural loss, generates negative reward prediction error (RPE). Through the lateral hypothalamus, the RPE strongly activates the brain's anti-reward center, the lateral habenula (LHb). LHb activation inhibits the medial prefrontal cortex (mPFC) that controls social competitiveness and reinforces retreats in contests. These results reveal the core neural mechanisms mutually promoting social status loss and depressive behaviors. The intertwined neuronal signaling controlling mPFC and LHb activities provides a mechanistic foundation for the crosstalk between social mobility and psychological disorder, unveiling a promising target for intervention.
Assuntos
Habenula , Status Social , Camundongos , Animais , Recompensa , Comportamento Social , Habenula/fisiologia , DepressãoRESUMO
Melanoma cells, deriving from neuroectodermal melanocytes, may exploit the nervous system's immune privilege for growth. Here we show that nerve growth factor (NGF) has both melanoma cell intrinsic and extrinsic immunosuppressive functions. Autocrine NGF engages tropomyosin receptor kinase A (TrkA) on melanoma cells to desensitize interferon γ signaling, leading to T and natural killer cell exclusion. In effector T cells that upregulate surface TrkA expression upon T cell receptor activation, paracrine NGF dampens T cell receptor signaling and effector function. Inhibiting NGF, either through genetic modification or with the tropomyosin receptor kinase inhibitor larotrectinib, renders melanomas susceptible to immune checkpoint blockade therapy and fosters long-term immunity by activating memory T cells with low affinity. These results identify the NGF-TrkA axis as an important suppressor of anti-tumor immunity and suggest larotrectinib might be repurposed for immune sensitization. Moreover, by enlisting low-affinity T cells, anti-NGF reduces acquired resistance to immune checkpoint blockade and prevents melanoma recurrence.
Assuntos
Melanoma , Receptor de Fator de Crescimento Neural , Humanos , Receptor de Fator de Crescimento Neural/genética , Receptor de Fator de Crescimento Neural/metabolismo , Fator de Crescimento Neural/genética , Fator de Crescimento Neural/metabolismo , Tropomiosina , Melanoma/terapia , Receptor trkA/genética , Receptor trkA/metabolismo , Citoproteção , Inibidores de Checkpoint Imunológico , Células T de Memória , Terapia de Imunossupressão , Imunoterapia , Receptores de Antígenos de Linfócitos TRESUMO
N6-methyladenosine (m6A) RNA modification plays important roles in the governance of gene expression and is temporally regulated in different cell states. In contrast to global m6A profiling in bulk sequencing, single-cell technologies for analyzing m6A heterogeneity are not extensively established. Here, we developed single-nucleus m6A-CUT&Tag (sn-m6A-CT) for simultaneous profiling of m6A methylomes and transcriptomes within a single nucleus using mouse embryonic stem cells (mESCs). m6A-CT is capable of enriching m6A-marked RNA molecules in situ, without isolating RNAs from cells. We adapted m6A-CT to the droplet-based single-cell omics platform and demonstrated high-throughput performance in analyzing nuclei isolated from thousands of cells from various cell types. We show that sn-m6A-CT profiling is sufficient to determine cell identity and allows the generation of cell-type-specific m6A methylome landscapes from heterogeneous populations. These indicate that sn-m6A-CT provides additional dimensions to multimodal datasets and insights into epitranscriptomic landscape in defining cell fate identity and states.
RESUMO
SifiNet is a robust and accurate computational pipeline for identifying distinct gene sets, extracting and annotating cellular subpopulations, and elucidating intrinsic relationships among these subpopulations. Uniquely, SifiNet bypasses the cell clustering stage, commonly integrated into other cellular annotation pipelines, thereby circumventing potential inaccuracies in clustering that may compromise subsequent analyses. Consequently, SifiNet has demonstrated superior performance in multiple experimental datasets compared with other state-of-the-art methods. SifiNet can analyze both single-cell RNA and ATAC sequencing data, thereby rendering comprehensive multi-omic cellular profiles. It is conveniently available as an open-source R package.
Assuntos
Análise de Célula Única , Software , Análise de Célula Única/métodos , Humanos , Anotação de Sequência Molecular , Algoritmos , Biologia Computacional/métodos , Análise de Sequência de RNA/métodos , Perfilação da Expressão Gênica/métodos , Sequenciamento de Cromatina por Imunoprecipitação/métodos , Análise por ConglomeradosRESUMO
Upon antigen engagement, augmented cytosolic reactive oxygen species (ROS) are needed to achieve optimal T cell receptor (TCR) signaling. However, uncontrolled ROS production is a prominent cause of necrosis, which elicits hyper-inflammation and tissue damage. Hence, it is critical to program activated T cells to achieve ROS equilibrium. Here, we determined that miR-23a is indispensable for effector CD4(+) T cell expansion, particularly by providing early protection from excessive necrosis. Mechanistically, miR-23a targeted PPIF, gatekeeper of the mitochondria permeability transition pore, thereby restricting ROS flux and maintaining mitochondrial integrity. Upon acute Listeria monocytogenes infection, deleting miR-23a in T cells resulted in excessive inflammation, massive liver damage, and a marked mortality increase, which highlights the essential role of miR-23a in maintaining immune homeostasis.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Listeria monocytogenes/imunologia , Listeriose/imunologia , Fígado/patologia , MicroRNAs/metabolismo , Mitocôndrias/metabolismo , Animais , Células Cultivadas , Peptidil-Prolil Isomerase F , Ciclofilinas/metabolismo , Homeostase , Camundongos , Camundongos Transgênicos , MicroRNAs/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Necrose , RNA Interferente Pequeno/genética , Espécies Reativas de Oxigênio/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais/genéticaRESUMO
Dendritic cells (DCs) orchestrate complex membrane trafficking through an interconnected transportation network linked together by Rab GTPases. Through a tandem affinity purification strategy and mass spectrometry, we depicted an interactomic landscape of major members of the mammalian Rab GTPase family. When complemented with imaging tools, this proteomic analysis provided a global view of intracellular membrane organization. Driven by this analysis, we investigated dynamic changes to the Rab32 subnetwork in DCs induced by L. monocytogenes infection and uncovered an essential role of this subnetwork in controlling the intracellular proliferation of L. monocytogenes. Mechanistically, Rab32 formed a persistent complex with two interacting proteins, PHB and PHB2, to encompass bacteria both during early phagosome formation and after L. monocytogenes escaped the original containment vacuole. Collectively, we have provided a functional compartmentalization overview and an organizational framework of intracellular Rab-mediated vesicle trafficking that can serve as a resource for future investigations.
Assuntos
Células Dendríticas/imunologia , Listeria monocytogenes/imunologia , Listeriose/imunologia , Complexos Multiproteicos/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Aciltransferases/metabolismo , Animais , Anti-Infecciosos/uso terapêutico , Linhagem Celular , Biologia Computacional , Contenção de Riscos Biológicos , Células Dendríticas/microbiologia , Listeria monocytogenes/crescimento & desenvolvimento , Listeriose/tratamento farmacológico , Camundongos , Proibitinas , Transporte Proteico , Proteínas Repressoras/metabolismo , Vacúolos/metabolismoRESUMO
The binding of T cell antigen receptors (TCRs) to specific complexes of peptide and major histocompatibility complex (pMHC) is typically of very low affinity, which necessitates the use of multimeric pMHC complexes to label T lymphocytes stably. We report here the development of pMHC complexes able to be crosslinked by ultraviolet irradiation; even as monomers, these efficiently and specifically stained cognate T cells. We also used this reagent to probe T cell activation and found that a covalently bound pMHC was more stimulatory than an agonist pMHC on lipid bilayers. This finding suggested that serial engagement of TCRs is dispensable for activation when a substantial fraction of TCRs are stably engaged. Finally, pMHC-bound TCRs were 'preferentially' transported into the central supramolecular activation cluster after activation, which suggested that ligand engagement enabled linkage of the TCR and its associated CD3 signaling molecules to the cytoskeleton.
Assuntos
Reagentes de Ligações Cruzadas/química , Complexo Principal de Histocompatibilidade/imunologia , Receptores de Antígenos de Linfócitos T/química , Linfócitos T/química , Animais , Complexo CD3/química , Complexo CD3/imunologia , Células Cultivadas , Corantes/química , Citoesqueleto/química , Citoesqueleto/imunologia , Ativação Linfocitária , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/imunologia , Transdução de Sinais/imunologia , Linfócitos T/imunologiaRESUMO
A breach of T cell tolerance is considered as a major step in the pathogenesis of rheumatoid arthritis. In collagen-induced arthritis (CIA) model, immunization with type II collagen (COL2) leads to arthritis in mice through T cells responding to the immunodominant COL2259-273 peptide. T cells could escape from thymus negative selection because endogenous COL2259-273 peptide only weakly binds to the major histocompatibility complex class II (MHCII) molecule Aq. To investigate the regulation of T cell tolerance, we used a new mouse strain BQ.Col2266E with homozygous D266E mutations in the Col2 gene leading to a replacement of the endogenous aspartic acid (D) to glutamic acid (E) at position 266 of the COL2259-273 peptide, resulting in stronger binding to Aq. We also established BQ.Col2264R mice carrying an additional K264R mutation changed the lysine (K) at position 264 to eliminate the major TCR recognition site. The BQ.Col2266E mice were fully resistant to CIA, while the BQ.Col2264R mice developed severe arthritis. Furthermore, we studied two of the most important non-MHCII genes associated with CIA, i.e., Ncf1 and Fcgr2b. Deficiency of either gene induced arthritis in BQ.Col2266E mice, and the downstream effects differ as Ncf1 deficiency reduced Tregs and was likely to decrease expression of autoimmune regulator (AIRE) while Fcgr2b did not. In conclusion, the new human-mimicking mouse model has strong T cell tolerance to COL2, which can be broken by deficiency of Fcgr2b or Ncf1, allowing activation of autoreactive T cells and development of arthritis.
Assuntos
Artrite Experimental , Doenças Autoimunes , NADPH Oxidases/metabolismo , Animais , Artrite Experimental/genética , Doenças Autoimunes/metabolismo , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Humanos , Tolerância Imunológica/genética , Camundongos , Receptores de IgG/genética , Linfócitos TRESUMO
Somatic mutations are major genetic contributors to cancers and many other age-related diseases. Many disease-causing somatic mutations can initiate clonal growth prior to the appearance of any disease symptoms, yet experimental models that can be used to examine clonal abnormalities are limited. We describe a mosaic analysis system with Cre or Tomato (MASCOT) for tracking mutant cells and demonstrate its utility for modeling clonal hematopoiesis. MASCOT can be induced to constitutively express either Cre-GFP or Tomato for lineage tracing of a mutant and a reference group of cells simultaneously. We conducted mosaic analysis to assess functions of the Id3 and/or Tet2 gene in hematopoietic cell development and clonal hematopoiesis. Using Tomato-positive cells as a reference population, we demonstrated the high sensitivity of this system for detecting cell-intrinsic phenotypes during short-term or long-term tracking of hematopoietic cells. Long-term tracking of Tet2 mutant or Tet2/Id3 double-mutant cells in our MASCOT model revealed a dynamic shift from myeloid expansion to lymphoid expansion and subsequent development of lymphoma. This work demonstrates the utility of the MASCOT method in mosaic analysis of single or combined mutations, making the system suitable for modeling somatic mutations identified in humans.
Assuntos
Integrases/genética , Modelos Genéticos , Mutação/genética , Solanum lycopersicum/genética , Animais , Hematopoiese Clonal/genética , Técnicas Genéticas , Linfoma/genética , Camundongos , Camundongos Transgênicos , Mosaicismo , Análise de Sequência de DNARESUMO
Mitochondria released from injured cells activate endothelial cells (ECs), fostering inflammatory processes, including allograft rejection. The stimulator of interferon genes (STING) senses endogenous mitochondrial DNA, triggering innate immune activation via NF-κB signaling. Here, we show that exogenous mitochondria exposure induces EC STING-NF-κB activation, promoting EC/effector memory T cell adhesion, which is abrogated by NF-κB and STING inhibitors. STING activation in mitochondrion-activated ECs is independent of canonical cGMP-AMP synthetase sensing/signaling, but rather is mediated by interferon gamma-inducible factor 16 (IFI16) and can be inhibited by IFI16 inhibition. Internalized mitochondria undergo mitofusion and STING-dependent mitophagy, leading to selective sequestration of internalized mitochondria. The exposure of donor hearts to exogenous mitochondria activates murine heart ECs in vivo. Collectively, our results suggest that IFI16-STING-NF-κB signaling regulates exogenous mitochondrion-induced EC activation and mitophagy, and exogenous mitochondria foster T cell-mediated CoBRR. These data suggest a novel, donor-directed, therapeutic approach toward mitigating perioperative allograft immunogenicity.
Assuntos
Transplante de Coração , NF-kappa B , Animais , Células Endoteliais/metabolismo , Transplante de Coração/efeitos adversos , Humanos , Camundongos , Mitocôndrias/metabolismo , NF-kappa B/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fosfoproteínas , Doadores de TecidosRESUMO
We have developed a single-molecule imaging technique that uses quantum-dot-labeled peptide-major histocompatibility complex (pMHC) ligands to study CD4(+) T cell functional sensitivity. We found that naive T cells, T cell blasts, and memory T cells could all be triggered by a single pMHC to secrete tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) cytokines with a rate of â¼1,000, â¼10,000, and â¼10,000 molecules/min, respectively, and that additional pMHCs did not augment secretion, indicating a digital response pattern. We also found that a single pMHC localized to the immunological synapse induced the slow formation of a long-lasting T cell receptor (TCR) cluster, consistent with a serial engagement mechanism. These data show that scaling up CD4(+) T cell cytokine responses involves increasingly efficient T cell recruitment rather than greater cytokine production per cell.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Antígenos de Histocompatibilidade Classe II/imunologia , Subpopulações de Linfócitos T/metabolismo , Imunidade Adaptativa , Sequência de Aminoácidos , Animais , Apresentação de Antígeno , Biotinilação , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Diferenciação Celular , Imunoconjugados , Memória Imunológica , Sinapses Imunológicas , Interleucina-2/metabolismo , Ativação Linfocitária , Dados de Sequência Molecular , Mariposas , Fragmentos de Peptídeos/imunologia , Pontos Quânticos , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Taxa Secretória , Análise de Célula Única , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Thymic positive selection is based on the interactions of T cell antigen receptors (TCRs) with self peptide-major histocompatibility complex (MHC) ligands, but the identity of selecting peptides for MHC class II-restricted TCRs and the functional consequences of this peptide specificity are not clear. Here we identify several endogenous self peptides that positively selected the MHC class II-restricted 5C.C7 TCR. The most potent of these also enhanced mature T cell activation, which supports the hypothesis that one function of positive selection is to produce T cells that can use particular self peptide-MHC complexes for activation and/or homeostasis. We also show that inhibiting the microRNA miR-181a resulted in maturation of T cells that overtly reacted toward these erstwhile positively selecting peptides. Therefore, miR-181a helps to guarantee the clonal deletion of particular moderate-affinity clones by modulating the TCR signaling threshold of thymocytes.
Assuntos
Antígenos de Histocompatibilidade Classe II/imunologia , Ativação Linfocitária , MicroRNAs/imunologia , Peptídeos/imunologia , Linfócitos T/imunologia , Animais , Células Cultivadas , Deleção Clonal , Regulação da Expressão Gênica , Camundongos , Camundongos Knockout , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/citologia , Timo/citologia , Timo/imunologiaRESUMO
Cellular senescence is a unique cell fate characterized by stable proliferative arrest and the extensive production and secretion of various inflammatory proteins, a phenomenon known as the senescence-associated secretory phenotype (SASP). The molecular mechanisms responsible for generating a SASP in response to senescent stimuli remain largely obscure. Here, using unbiased gene expression profiling, we discover that the scavenger receptor CD36 is rapidly upregulated in multiple cell types in response to replicative, oncogenic, and chemical senescent stimuli. Moreover, ectopic CD36 expression in dividing mammalian cells is sufficient to initiate the production of a large subset of the known SASP components via activation of canonical Src-p38-NF-κB signaling, resulting in the onset of a full senescent state. The secretome is further shown to be ligand-dependent, as amyloid-beta (Aß) is sufficient to drive CD36-dependent NF-κB and SASP activation. Finally, loss-of-function experiments revealed a strict requirement for CD36 in secretory molecule production during conventional senescence reprogramming. Taken together, these results uncover the Aß-CD36-NF-κB signaling axis as an important regulator of the senescent cell fate via induction of the SASP.
Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Antígenos CD36/fisiologia , Senescência Celular/fisiologia , NF-kappa B/metabolismo , Antígenos CD36/genética , Células Cultivadas , Senescência Celular/genética , Fibroblastos/metabolismo , Humanos , Mutação com Perda de Função , Transdução de SinaisRESUMO
BACKGROUND: Tumor purity is the percent of cancer cells present in a sample of tumor tissue. The non-cancerous cells (immune cells, fibroblasts, etc.) have an important role in tumor biology. The ability to determine tumor purity is important to understand the roles of cancerous and non-cancerous cells in a tumor. METHODS: We applied a supervised machine learning method, XGBoost, to data from 33 TCGA tumor types to predict tumor purity using RNA-seq gene expression data. RESULTS: Across the 33 tumor types, the median correlation between observed and predicted tumor-purity ranged from 0.75 to 0.87 with small root mean square errors, suggesting that tumor purity can be accurately predicted υσινγ expression data. We further confirmed that expression levels of a ten-gene set (CSF2RB, RHOH, C1S, CCDC69, CCL22, CYTIP, POU2AF1, FGR, CCL21, and IL7R) were predictive of tumor purity regardless of tumor type. We tested whether our set of ten genes could accurately predict tumor purity of a TCGA-independent data set. We showed that expression levels from our set of ten genes were highly correlated (ρ = 0.88) with the actual observed tumor purity. CONCLUSIONS: Our analyses suggested that the ten-gene set may serve as a biomarker for tumor purity prediction using gene expression data.
Assuntos
Biomarcadores Tumorais , Neoplasias/genética , Biologia Computacional/métodos , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/diagnóstico , Reprodutibilidade dos Testes , Análise de Sequência de RNA , Aprendizado de Máquina SupervisionadoRESUMO
Several recent clinical trials have successfully incorporated a costimulatory domain derived from either CD28 or 4-1BB with the original CD3ζ T cell activating domain to form second-generation chimeric antigen receptors (CARs) that can increase the responsiveness and survival of CAR-engineered T (CAR-T) cells. However, a rigorous assessment of the individual benefits of these costimulatory components relative to the in vivo performance of infused T cells in patients is still lacking. Therefore, we have designed a study that allows us to investigate and compare the impact of different costimulatory signal domains on CAR-T cells in vivo. Patients with B cell leukemia were infused with a mixture of two types of CD19-specific CAR-T cells, individually bearing CD28 (28ζ) and 4-1BB (BBζ) costimulatory signaling domains. We found that such a clinical procedure was feasible and safe. Complete remission (CR) was observed in five of seven enrolled patients, with two patients exhibiting durable CR lasting more than 15 months. The in vivo expansion pattern of 28ζ and BBζ CAR-T cells varied significantly among individual patients. These results confirm a feasible method of comparing different CAR designs within individual patients, potentially offering objective insights that may facilitate the development of optimal CAR-T cell-based immunotherapies.
Assuntos
Antígenos CD28/imunologia , Imunoterapia Adotiva , Leucemia Linfocítica Crônica de Células B/imunologia , Leucemia Linfocítica Crônica de Células B/terapia , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos Quiméricos/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologia , Adolescente , Adulto , Idoso , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antígenos CD28/metabolismo , Criança , Pré-Escolar , Terapia Combinada , Modelos Animais de Doenças , Feminino , Vetores Genéticos/genética , Humanos , Imunoterapia Adotiva/efeitos adversos , Imunoterapia Adotiva/métodos , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/metabolismo , Masculino , Camundongos Transgênicos , Pessoa de Meia-Idade , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos Quiméricos/genética , Retroviridae/genética , Resultado do Tratamento , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Adulto JovemRESUMO
Homeostatic maintenance of T cells with broad clonal diversity is influenced by both continuing output of young T cells from the thymus and ongoing turnover of preexisting clones in the periphery. In the absence of infection, self and commensal antigens are thought to play important roles in selection and homeostatic maintenance of the T-cell pool. Most naïve T cells are short-lived due to lack of antigen encounter, whereas antigen-experienced T cells may survive and persist as long-lived clones. Thus far, little is known about the homeostasis, antigenic specificity, and clonal diversity of long-lived T-cell clones in peripheral lymphoid organs under healthy living conditions. To identify long-lived T-cell clones in mice, we designed a lineage-tracing method to label a wave of T cells produced in the thymus of young mice. After aging the mice for 1.5 y, we found that lineage-tracked T cells consisted of primarily memory-like T cells and T regulatory cells. T-cell receptor repertoire analysis revealed that the lineage-tracked CD4 memory-like T cells and T regulatory cells exhibited age-dependent enrichment of shared clonotypes. Furthermore, these shared clonotypes were found across different mice maintained in the same housing condition. These findings suggest that nonrandom and shared antigens are involved in controlling selection, retention, and immune tolerance of long-lived T-cell clones under healthy living conditions.
Assuntos
Envelhecimento/imunologia , Homeostase/imunologia , Seleção Genética/imunologia , Linfócitos T/imunologia , Envelhecimento/genética , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Células Clonais , Citocinas/genética , Citocinas/imunologia , Citocinas/metabolismo , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/imunologia , Fatores de Transcrição Forkhead/metabolismo , Homeostase/genética , Memória Imunológica/genética , Memória Imunológica/imunologia , Camundongos da Linhagem 129 , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Timo/citologia , Timo/imunologia , Timo/metabolismoRESUMO
Follicular helper T (Tfh) cells provide selection signals to germinal center B cells, which is essential for long-lived antibody responses. High CXCR5 and low CCR7 expression facilitates their homing to B cell follicles and distinguishes them from T helper 1 (Th1), Th2, and Th17 cells. Here, we showed that Bcl-6 directs Tfh cell differentiation: Bcl-6-deficient T cells failed to develop into Tfh cells and could not sustain germinal center responses, whereas forced expression of Bcl-6 in CD4(+) T cells promoted expression of the hallmark Tfh cell molecules CXCR5, CXCR4, and PD-1. Bcl-6 bound to the promoters of the Th1 and Th17 cell transcriptional regulators T-bet and RORgammat and repressed IFN-gamma and IL-17 production. Bcl-6 also repressed expression of many microRNAs (miRNAs) predicted to control the Tfh cell signature, including miR-17-92, which repressed CXCR5 expression. Thus, Bcl-6 positively directs Tfh cell differentiation, through combined repression of miRNAs and transcription factors.
Assuntos
Linhagem da Célula , Proteínas de Ligação a DNA/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Fatores de Transcrição/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Citocinas/biossíntese , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Humanos , Camundongos , Camundongos Knockout , MicroRNAs/genética , Família Multigênica , Ligação Proteica , Proteínas Proto-Oncogênicas c-bcl-6 , Linfócitos T Auxiliares-Indutores/citologia , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Regulação para CimaRESUMO
To ensure lifelong immunocompetency, naïve and memory T cells must be adequately maintained in the peripheral lymphoid tissues. Homeostatic maintenance of T cells is controlled by tonic signaling through T cell antigen receptors and common γ chain cytokine receptors. In this study, we identify the highly expressed microRNA miR-191 as a key regulator of naïve, memory, and regulatory T cell homeostasis. Conditional deletion of miR-191 using LckCre resulted in preferential loss of peripheral CD4+ regulatory T cells as well as naïve and memory CD8+ T cells. This preferential loss stemmed from reduced survival following deficient cytokine signaling and STAT5 activation. Mechanistically, insulin receptor substrate 1 (Irs1) is a direct target of miR-191, and dysregulated IRS1 expression antagonizes STAT5 activation. Our study identifies a novel role for microRNAs in fine-tuning immune homeostasis and thereby maintaining the lymphocyte reservoir necessary to mount productive immune responses.
Assuntos
Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Subunidade gama Comum de Receptores de Interleucina/imunologia , MicroRNAs/genética , Transdução de Sinais , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Morte Celular , Sobrevivência Celular , Citocinas/imunologia , Deleção de Genes , Proteínas Substratos do Receptor de Insulina/genética , Proteínas Substratos do Receptor de Insulina/imunologia , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/imunologia , Células NIH 3T3 , Receptores de Antígenos de Linfócitos T/imunologia , Regulação para CimaRESUMO
MicroRNAs (miRs) play important roles in orchestrating many aspects of the immune response. The miR-17-92 cluster, which encodes 6 miRs including 17, 18a, 19a, 20a, 19b-1, and 92-1, is among the best characterized of these miRs. The miR-17-92 cluster has been shown to regulate a variety of immune responses including infection, tumor, and autoimmunity, but the role of this cluster in T-cell response to alloantigens has not been previously explored. By using major histocompatibility complex (MHC)-matched, -mismatched, and haploidentical murine models of allogeneic bone marrow transplantation (allo-BMT), we demonstrate that the expression of miR-17-92 on donor T cells is essential for the induction of graft-versus-host disease (GVHD), but dispensable for the graft-versus-leukemia (GVL) effect. The miR-17-92 plays a major role in promoting CD4 T-cell activation, proliferation, survival, and Th1 differentiation, while inhibiting Th2 and iTreg differentiation. Alternatively, miR-17-92 may promote migration of CD8 T cells to GVHD target organs, but has minimal impact on CD8 T-cell proliferation, survival, or cytolytic function, which could contribute to the preserved GVL effect mediated by T cells deficient for miR-17-92. Furthermore, we evaluated a translational approach and found that systemic administration of antagomir to block miR-17 or miR-19b in this cluster significantly inhibited alloreactive T-cell expansion and interferon-γ (IFNγ) production, and prolonged the survival in recipients afflicted with GVHD while preserving the GVL effect. Taken together, the current work provides a strong rationale and demonstrates the feasibility to target miR-17-92 for the control of GVHD while preserving GVL activity after allo-BMT.
Assuntos
Doença Enxerto-Hospedeiro/imunologia , Leucemia Experimental/imunologia , MicroRNAs/genética , MicroRNAs/imunologia , Linfócitos T/imunologia , Aloenxertos , Animais , Transplante de Medula Óssea , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Doença Enxerto-Hospedeiro/genética , Efeito Enxerto vs Leucemia/genética , Efeito Enxerto vs Leucemia/imunologia , Interferon gama/biossíntese , Leucemia Experimental/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , MicroRNAs/antagonistas & inibidores , Oligonucleotídeos/farmacologiaRESUMO
Forkhead box P3(+) (Foxp3(+)) regulatory T cells (Tregs) are crucial for peripheral tolerance. During inflammation, steady Foxp3 expression in Tregs is essential for maintaining their lineage identity and suppressive function. However, the molecular machinery governing Tregs' resilience to inflammation-induced Foxp3 destabilization remains elusive. Here, we demonstrate that methyl-CpG binding protein 2 (MeCP2), an eminent epigenetic regulator known primarily as the etiological factor of Rett syndrome, is critical to sustain Foxp3 expression in Tregs during inflammation. In response to inflammatory stimuli, MeCP2 is specifically recruited to the Conserved Non-Coding sequence 2 region of the foxp3 locus, where it collaborates with cAMP responsive element binding protein 1 to promote local histone H3 acetylation, thereby counteracting inflammation-induced epigenetic silencing of foxp3. Consequently, Treg-specific deletion of MeCP2 causes spontaneous immune activation in mice and failure in protection against autoimmunity. Furthermore, we demonstrate that Foxp3 expression in MeCP2-deficient Tregs diminishes with time, resulting in their failure to suppress effector T-cell-mediated colitis. Thus, MeCP2 serves as a critical safeguard that confers Tregs with resilience against inflammation.