RESUMO
Alcelaphine gammaherpesvirus 1 (AlHV-1) asymptomatically persists in its natural host, the wildebeest. However, cross-species transmission to cattle results in the induction of an acute and lethal peripheral T cell lymphoma-like disease (PTCL), named malignant catarrhal fever (MCF). Our previous findings demonstrated an essential role for viral genome maintenance in infected CD8+ T lymphocytes but the exact mechanism(s) leading to lymphoproliferation and MCF remained unknown. To decipher how AlHV-1 dysregulates T lymphocytes, we first examined the global phenotypic changes in circulating CD8+ T cells after experimental infection of calves. T cell receptor repertoire together with transcriptomics and epigenomics analyses demonstrated an oligoclonal expansion of infected CD8+ T cells displaying effector and exhaustion gene signatures, including GZMA, GNLY, PD-1, and TOX2 expression. Then, among viral genes expressed in infected CD8+ T cells, we uncovered A10 that encodes a transmembrane signaling protein displaying multiple tyrosine residues, with predicted ITAM and SH3 motifs. Impaired A10 expression did not affect AlHV-1 replication in vitro but rendered AlHV-1 unable to induce MCF. Furthermore, A10 was phosphorylated in T lymphocytes in vitro and affected T cell signaling. Finally, while AlHV-1 mutants expressing mutated forms of A10 devoid of ITAM or SH3 motifs (or both) were able to induce MCF, a recombinant virus expressing a mutated form of A10 unable to phosphorylate its tyrosine residues resulted in the lack of MCF and protected against a wild-type virus challenge. Thus, we could characterize the nature of this γ-herpesvirus-induced PTCL-like disease and identify an essential mechanism explaining its development.
Assuntos
Linfócitos T CD8-Positivos , Gammaherpesvirinae , Animais , Linfócitos T CD8-Positivos/imunologia , Gammaherpesvirinae/genética , Gammaherpesvirinae/imunologia , Bovinos , Febre Catarral Maligna/virologia , Febre Catarral Maligna/imunologia , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/virologiaRESUMO
BACKGROUND AND AIMS: Liver macrophages fulfill various homeostatic functions and represent an essential line of defense against pathogenic insults. However, it remains unclear whether a history of infectious disease in the liver instructs long-term alterations to the liver macrophage compartment. METHODS: We utilized a curable model of parasitic infection invoked by the protozoan parasite Trypanosoma brucei brucei to investigate whether infection history can durably reshape hepatic macrophage identity and function. Employing a combination of fate mapping, single cell CITE-sequencing, single nuclei multiome analysis, epigenomic analysis, and functional assays, we studied the alterations to the liver macrophage compartment during and after the resolution of infection. RESULTS: We show that T. b. brucei infection alters the composition of liver-resident macrophages, leading to the infiltration of monocytes that differentiate into various infection-associated macrophage populations with divergent transcriptomic profiles. Whereas infection-associated macrophages disappear post-resolution of infection, monocyte-derived macrophages engraft in the liver, assume a Kupffer cell (KC)-like profile and co-exist with embryonic KCs in the long-term. Remarkably, the prior exposure to infection imprinted an altered transcriptional program on post-resolution KCs that was underpinned by an epigenetic remodeling of KC chromatin landscapes and a shift in KC ontogeny, along with transcriptional and epigenetic alterations in their niche cells. This reprogramming altered KC functions and was associated with increased resilience to a subsequent bacterial infection. CONCLUSION: Our study demonstrates that a prior exposure to a parasitic infection induces trained immunity in KCs, reshaping their identity and function in the long-term. IMPACT AND IMPLICATIONS: Although the liver is frequently affected during infections, and despite housing a major population of resident macrophages known as Kupffer cells (KCs), it is currently unclear whether infections can durably alter KCs and their niche cells. Our study provides a comprehensive investigation into the long-term impact of a prior, cured parasitic infection, unveiling long-lasting ontogenic, epigenetic, transcriptomic and functional changes to KCs as well as KC niche cells, which may contribute to KC remodeling. Our data suggest that infection history may continuously reprogram KCs throughout life with potential implications for subsequent disease susceptibility in the liver, influencing preventive and therapeutic approaches.
RESUMO
Brucellosis is one of the most widespread bacterial zoonoses worldwide. Here, our aim was to identify the effector mechanisms controlling the early stages of intranasal infection with Brucella in C57BL/6 mice. During the first 48 hours of infection, alveolar macrophages (AMs) are the main cells infected in the lungs. Using RNA sequencing, we identified the aconitate decarboxylase 1 gene (Acod1; also known as Immune responsive gene 1), as one of the genes most upregulated in murine AMs in response to B. melitensis infection at 24 hours post-infection. Upregulation of Acod1 was confirmed by RT-qPCR in lungs infected with B. melitensis and B. abortus. We observed that Acod1-/- C57BL/6 mice display a higher bacterial load in their lungs than wild-type (wt) mice following B. melitensis or B. abortus infection, demonstrating that Acod1 participates in the control of pulmonary Brucella infection. The ACOD1 enzyme is mostly produced in mitochondria of macrophages, and converts cis-aconitate, a metabolite in the Krebs cycle, into itaconate. Dimethyl itaconate (DMI), a chemically-modified membrane permeable form of itaconate, has a dose-dependent inhibitory effect on Brucella growth in vitro. Interestingly, structural analysis suggests the binding of itaconate into the binding site of B. abortus isocitrate lyase. DMI does not inhibit multiplication of the isocitrate lyase deletion mutant ΔaceA B. abortus in vitro. Finally, we observed that, unlike the wt strain, the ΔaceA B. abortus strain multiplies similarly in wt and Acod1-/- C57BL/6 mice. These data suggest that bacterial isocitrate lyase might be a target of itaconate in AMs.
Assuntos
Brucelose/imunologia , Carboxiliases/imunologia , Pneumopatias/imunologia , Macrófagos Alveolares/imunologia , Animais , Isocitrato Liase/metabolismo , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Bronchiolitis obliterans syndrome (BOS) is a fibrotic disease that is heavily responsible for the high mortality rates after lung transplantation. Myofibroblasts are primary effectors of this fibrotic process, but their origin is still debated. The purpose of this work was to identify the precursors of mesenchymal cells responsible for post-transplant airway fibro-obliteration.Lineage-tracing tools were used to track or deplete potential sources of myofibroblasts in the heterotopic tracheal transplantation model. Allografts were analysed by histology, confocal microscopy, flow cytometry or single-cell transcriptomic analysis. BOS explants were evaluated by histology and confocal microscopy.Myofibroblasts in the allografts were recipient-derived. When recipient mice were treated with tacrolimus, we observed rare epithelial-to-mesenchymal transition phenomena and an overall increase in donor-derived myofibroblasts (p=0.0467), but the proportion of these cells remained low (7%). Haematopoietic cells, and specifically the mononuclear phagocyte system, gave rise to the majority of myofibroblasts found in occluded airways. Ablation of Cx3cR1+ cells decreased fibro-obliteration (p=0.0151) and myofibroblast accumulation (p=0.0020). Single-cell RNA sequencing revealed similarities between myeloid-derived cells from allografts and both murine and human samples of lung fibrosis. Finally, myofibroblasts expressing the macrophage marker CD68 were increased in BOS explants when compared to controls (14.4% versus 8.5%, p=0.0249).Recipient-derived myeloid progenitors represent a clinically relevant source of mesenchymal cells infiltrating the airways after allogeneic transplantation. Therapies targeting the mononuclear phagocyte system could improve long-term outcomes after lung transplantation.
Assuntos
Bronquiolite Obliterante , Transplante de Pulmão , Animais , Fibrose , Camundongos , Sistema Fagocitário Mononuclear , Transplante HomólogoRESUMO
BACKGROUND & AIMS: Severe forms of alcohol-related liver disease are associated with increased susceptibility to infections which are associated with poor prognosis. The cellular and molecular mechanisms responsible for this altered host defense are incompletely understood. METHODS: We performed whole blood phenotypic analysis and ex vivo stimulation with various pathogen-associated molecular patterns (PAMPs). We included 34 patients with alcohol-related cirrhosis (18 of whom had biopsy-proven severe alcoholic hepatitis [sAH]), 12 healthy controls and 11 patients with chronic alcohol consumption without significant liver disease. We also evaluated the transcriptomic (RNA-seq) and chromatin accessibility (ATAC-seq) profiles of CD14+ monocytes from a subset of patients. RESULTS: Circulating monocytes and conventional dendritic cells (DCs) from patients with sAH displayed complex alterations characterized by increased expression of both activating and inhibitory surface markers and an impaired pro-inflammatory response upon stimulation with PAMPs representative of gram-negative bacteria (lipopolysaccharide, Pam3CSK4) or fungal pathogens (Zymosan). Their decreased ability to produce more than 1 cytokine (polyfunctionality) upon PAMP stimulation correlated with the risk of developing infection at 28 days or mortality at 90 days. The presence of acute-on-chronic liver failure in patients with sAH did not significantly modify the immune profile of monocytes and DCs. Moreover, CD14+ monocytes of patients with sAH displayed altered transcriptional and epigenomic profiles characterized by downregulation of key innate immune and metabolic pathways and upregulation of important immunomodulatory factors. CONCLUSIONS: In patients with sAH, the altered transcriptional program and functional properties of monocytes that contribute to patients' susceptibility to infection have strong epigenetic determinants. LAY SUMMARY: Patients with severe alcoholic hepatitis are at increased risk of infections, which contribute to the poor prognosis associated with the disease. Herein, we show that epigenetic determinants underly the immune cell dysfunction and inappropriate responses to pathogens that are associated with severe alcoholic hepatitis.
Assuntos
Citocinas/metabolismo , Epigênese Genética , Hepatite Alcoólica , Infecções , Receptores de Lipopolissacarídeos/análise , Monócitos/imunologia , Biópsia/métodos , Células Dendríticas/imunologia , Progressão da Doença , Suscetibilidade a Doenças/epidemiologia , Regulação para Baixo , Feminino , Bactérias Gram-Negativas/isolamento & purificação , Hepatite Alcoólica/sangue , Hepatite Alcoólica/imunologia , Hepatite Alcoólica/mortalidade , Hepatite Alcoólica/patologia , Humanos , Infecções/epidemiologia , Infecções/microbiologia , Fígado/patologia , Masculino , Prognóstico , Medição de Risco/métodosRESUMO
Adipose tissue homeostasis relies on the interplay between several regulatory lineages, such as type 2 innate lymphoid cells (ILC2s), T helper 2 (Th2) cells, regulatory T cells, eosinophils, and type 2 macrophages. Among them, ILC2s are numerically the dominant source of type 2 cytokines and are considered as major regulators of adiposity. Despite the overlap in immune effector molecules and sensitivity to alarmins (thymic stromal lymphopoietin and interleukin-33) between ILC2s and resident memory Th2 lymphocytes, the role of the adaptive axis of type 2 immunity remains unclear. We show that mice deficient in CD27, a member of the tumor necrosis factor receptor superfamily, are more resistant to obesity and associated disorders. A comparative analysis of the CD4 compartment of both strains revealed higher numbers of fat-resident memory Th2 cells in the adipose tissue of CD27 knockout mice, which correlated with decreased programmed cell death protein 1-induced apoptosis. Our data point to a non-redundant role for Th2 lymphocytes in obesogenic conditions.
Assuntos
Imunidade Inata , Linfócitos , Animais , Camundongos , Citocinas/metabolismo , Homeostase , Interleucina-33 , Gordura Intra-Abdominal/metabolismo , Linfócitos/metabolismo , Células Th2 , Membro 7 da Superfamília de Receptores de Fatores de Necrose TumoralRESUMO
Introduction: Most T lymphocytes, including regulatory T cells, express the CD27 costimulatory receptor in steady state conditions. There is evidence that CD27 engagement on conventional T lymphocytes favors the development of Th1 and cytotoxic responses in mice and humans, but the impact on the regulatory lineage is unknown. Methods: In this report, we examined the effect of constitutive CD27 engagement on both regulatory and conventional CD4+ T cells in vivo, in the absence of intentional antigenic stimulation. Results: Our data show that both T cell subsets polarize into type 1 Tconvs or Tregs, characterized by cell activation, cytokine production, response to IFN-γ and CXCR3-dependent migration to inflammatory sites. Transfer experiments suggest that CD27 engagement triggers Treg activation in a cell autonomous fashion. Conclusion: We conclude that CD27 may regulate the development of Th1 immunity in peripheral tissues as well as the subsequent switch of the effector response into long-term memory.
Assuntos
Subpopulações de Linfócitos T , Linfócitos T Reguladores , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral , Animais , Humanos , Camundongos , Antígenos/metabolismo , Ligante CD27/metabolismo , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/metabolismo , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismoRESUMO
The prolyl hydroxylase domain/hypoxia-inducible factor (PHD/HIF) pathway has been implicated in a wide range of immune and inflammatory processes, including in the oxygen-deprived tumor microenvironment. To examine the effect of HIF stabilization in antitumor immunity, we deleted Phd2 selectively in T lymphocytes using the cre/lox system. We show that the deletion of PHD2 in lymphocytes resulted in enhanced regression of EG7-OVA tumors, in a HIF-1α-dependent manner. The enhanced control of neoplastic growth correlated with increased polyfunctionality of CD8+ tumor-infiltrating lymphocytes, as indicated by enhanced expression of IFNγ, TNFα, and granzyme B. Phenotypic and transcriptomic analyses pointed to a key role of glycolysis in sustaining CTL activity in the tumor bed and identified the PHD2/HIF-1 pathway as a potential target for cancer immunotherapy.
Assuntos
Prolina Dioxigenases do Fator Induzível por Hipóxia , Neoplasias , Humanos , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Oxigênio , Linfócitos T CD8-Positivos/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Microambiente TumoralRESUMO
The co-inhibitory programmed death (PD)-1 signaling pathway plays a major role in the context of tumor-specific T cell responses. Conversely, it also contributes to the maintenance of peripheral tolerance, as patients receiving anti-PD-1 treatment are prone to developing immune-related adverse events. Yet, the physiological role of the PD-1/PDL-1 axis in T cell homeostasis is still poorly understood. Herein, we show that under steady-state conditions, the absence of PD-1 signaling led to a preferential expansion of CD8+ T cells in the liver. These cells exhibit an oligoclonal T cell receptor (TCR) repertoire and a terminally differentiated exhaustion profile. The transcription factor EOMES is required for the clonal expansion and acquisition of this differentiation program. Finally, single-cell transcriptomics coupled with TCR repertoire analysis support the notion that these cells arise locally from liver-resident memory CD8+ T cells. Overall, we show a role for PD-1 signaling in liver memory T cell homeostasis.
Assuntos
Linfócitos T CD8-Positivos , Regulação da Expressão Gênica , Humanos , Linfócitos T CD8-Positivos/metabolismo , Fígado/metabolismo , Transdução de Sinais , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismoRESUMO
The oxygen sensor prolyl hydroxylase domain 2 (PHD2) plays an important role in cell hypoxia adaptation by regulating the stability of HIF proteins (HIF1α and HIF2α) in numerous cell types, including T lymphocytes. The role of oxygen sensor on immune cells, particularly on regulatory T cell (Treg) function, has not been fully elucidated. The purpose of our study was to evaluate the role of PHD2 in the regulation of Treg phenotype and function. We demonstrate herein that selective ablation of PHD2 expression in Treg (PHD2ΔTreg mice) leads to a spontaneous systemic inflammatory syndrome, as evidenced by weight loss, development of a rectal prolapse, splenomegaly, shortening of the colon, and elevated expression of IFN-γ in the mesenteric lymph nodes, intestine, and spleen. PHD2 deficiency in Tregs led to an increased number of activated CD4 conventional T cells expressing a Th1-like effector phenotype. Concomitantly, the expression of innate-type cytokines such as Il1b, Il12a, Il12b, and Tnfa was found to be elevated in peripheral (gut) tissues and spleen. PHD2ΔTreg mice also displayed an enhanced sensitivity to dextran sodium sulfate-induced colitis and toxoplasmosis, suggesting that PHD2-deficient Tregs did not efficiently control inflammatory response in vivo, particularly those characterized by IFN-γ production. Further analysis revealed that Treg dysregulation was largely prevented in PHD2-HIF2α (PHD2-HIF2αΔTreg mice), but not in PHD2-HIF1α (PHD2-HIF1αΔTreg mice) double KOs, suggesting an important and possibly selective role of the PHD2-HIF2α axis in the control of Treg function. Finally, the transcriptomic analysis of PHD2-deficient Tregs identified the STAT1 pathway as a target of the PHD2-HIF2α axis in regulatory T cell phenotype and in vivo function.
Assuntos
Colite , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Linfócitos T Reguladores , Animais , Colite/induzido quimicamente , Subunidade alfa do Fator 1 Induzível por Hipóxia , Camundongos , Oxigênio , Pró-Colágeno-Prolina Dioxigenase , Prolil HidroxilasesRESUMO
Developmental thymic waves of innate-like and adaptive-like γδ T cells have been described, but the current understanding of γδ T cell development is mainly limited to mouse models. Here, we combine single cell (sc) RNA gene expression and sc γδ T cell receptor (TCR) sequencing on fetal and pediatric γδ thymocytes in order to understand the ontogeny of human γδ T cells. Mature fetal γδ thymocytes (both the Vγ9Vδ2 and nonVγ9Vδ2 subsets) are committed to either a type 1, a type 3 or a type 2-like effector fate displaying a wave-like pattern depending on gestation age, and are enriched for public CDR3 features upon maturation. Strikingly, these effector modules express different CDR3 sequences and follow distinct developmental trajectories. In contrast, the pediatric thymus generates only a small effector subset that is highly biased towards Vγ9Vδ2 TCR usage and shows a mixed type 1/type 3 effector profile. Thus, our combined dataset of gene expression and detailed TCR information at the single-cell level identifies distinct functional thymic programming of γδ T cell immunity in human.
Assuntos
Subpopulações de Linfócitos T , Timócitos , Animais , Diferenciação Celular/genética , Criança , Humanos , Camundongos , RNA/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Análise de Célula Única , Timo/metabolismoRESUMO
Severe COVID-19 disease is associated with dysregulation of the myeloid compartment during acute infection. Survivors frequently experience long-lasting sequelae, but little is known about the eventual persistence of this immune alteration. Herein, we evaluated TLR-induced cytokine responses in a cohort of mild to critical patients during acute or convalescent phases (n = 97). In the acute phase, we observed impaired cytokine production by monocytes in the patients with the most severe COVID-19. This capacity was globally restored in convalescent patients. However, we observed increased responsiveness to TLR1/2 ligation in patients who recovered from severe disease, indicating that these cells display distinct functional properties at the different stages of the disease. In patients with acute severe COVID-19, we identified a specific transcriptomic and epigenomic state in monocytes that can account for their functional refractoriness. The molecular profile of monocytes from recovering patients was distinct and characterized by increased chromatin accessibility at activating protein 1 (AP1) and MAF loci. These results demonstrate that severe COVID-19 infection has a profound impact on the differentiation status and function of circulating monocytes, during both the acute and the convalescent phases, in a completely distinct manner. This could have important implications for our understanding of short- and long-term COVID-19-related morbidity.
Assuntos
COVID-19 , Citocinas/metabolismo , Progressão da Doença , Humanos , Monócitos/metabolismo , SARS-CoV-2RESUMO
Retinoids triggers differentiation of acute promyelocytic leukemia (APL) blasts by transcriptional regulation of myeloid regulatory genes. Using a microarray approach, we have identified a novel retinoid-responsive gene (CXXC5) encoding a nuclear factor, retinoid-inducible nuclear factor (RINF), that contains a CXXC-type zinc-finger motif. RINF expression correlates with retinoid-induced differentiation of leukemic cells and with cytokine-induced myelopoiesis of normal CD34(+) progenitors. Furthermore, short hairpin RNA (shRNA) interference suggests for this gene a regulatory function in both normal and tumoral myelopoiesis. Interestingly, RINF localizes to 5q31.3, a small region often deleted in myeloid leukemia (acute myeloid leukemia [AML]/myelodysplasia [MDS]) and suspected to harbor one or several tumor suppressor gene.
Assuntos
Proteínas de Transporte/fisiologia , Neoplasias Hematológicas/genética , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Mielopoese/genética , Sequência de Aminoácidos , Proteínas de Transporte/genética , Proteínas de Ligação a DNA , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Células Precursoras de Granulócitos/efeitos dos fármacos , Células Precursoras de Granulócitos/fisiologia , Células HL-60 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Células K562 , Modelos Biológicos , Dados de Sequência Molecular , Mielopoese/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos , Homologia de Sequência de Aminoácidos , Fatores de Transcrição , Tretinoína/farmacologia , Células Tumorais CultivadasRESUMO
Cancer is caused primarily by genomic alterations resulting in deregulation of gene regulatory circuits in key growth, apoptosis, or DNA repair pathways. Multiple genes associated with the initiation and development of tumors are also regulated at the level of mRNA decay, through the recruitment of RNA-binding proteins to AU-rich elements (AREs) located in their 3'-untranslated regions. One of these ARE-binding proteins, tristetraprolin (TTP; encoded by Zfp36), is consistently dysregulated in many human malignancies. Herein, using regulated overexpression or conditional ablation in the context of cutaneous chemical carcinogenesis, we show that TTP represents a critical regulator of skin tumorigenesis. We provide evidence that TTP controlled both tumor-associated inflammation and key oncogenic pathways in neoplastic epidermal cells. We identify Areg as a direct target of TTP in keratinocytes and show that EGFR signaling potentially contributed to exacerbated tumor formation. Finally, single-cell RNA-Seq analysis indicated that ZFP36 was downregulated in human malignant keratinocytes. We conclude that TTP expression by epidermal cells played a major role in the control of skin tumorigenesis.
Assuntos
Carcinogênese/metabolismo , Queratinócitos/metabolismo , Neoplasias Cutâneas/metabolismo , Pele/metabolismo , Tristetraprolina/metabolismo , Regiões 3' não Traduzidas , Elementos Ricos em Adenilato e Uridilato , Animais , Carcinogênese/genética , Modelos Animais de Doenças , Regulação para Baixo , Receptores ErbB/metabolismo , Redes Reguladoras de Genes , Humanos , Inflamação/metabolismo , Camundongos Endogâmicos C57BL , Estabilidade de RNA , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/genéticaRESUMO
c-Jun N-terminal protein kinase 1 (JNK1) is involved in multiple biological processes but its implication in inflammatory skin diseases is still poorly defined. Herein, we studied the role of JNK1 in the context of Aldara®-induced skin inflammation. We observed that constitutive ablation of JNK1 reduced Aldara®-induced acanthosis and expression of inflammatory markers. Conditional deletion of JNK1 in myeloid cells led to reduced skin inflammation, a finding that was associated with impaired Aldara®-induced inflammasome activation in vitro. Next, we evaluated the specific role of JNK1 in epidermal cells. We observed reduced Aldara®-induced acanthosis despite similar levels of inflammatory markers. Transcriptomic and epigenomic analysis of keratinocytes revealed the potential involvement of JNK1 in the EGFR signaling pathway. Finally, we show that inhibition of the EGFR pathway reduced Aldara®-induced acanthosis. Taken together, these data indicate that JNK1 plays a dual role in the context of psoriasis by regulating the production of inflammatory cytokines by myeloid cells and the sensitivity of keratinocytes to EGFR ligands. These results suggest that JNK1 could represent a valuable therapeutic target in the context of psoriasis.
Assuntos
Receptores ErbB/metabolismo , Queratinócitos/enzimologia , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Células Mieloides/enzimologia , Psoríase/enzimologia , Pele/enzimologia , Animais , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Epigenoma , Receptores ErbB/genética , Feminino , Imiquimode , Mediadores da Inflamação/metabolismo , Queratinócitos/imunologia , Queratinócitos/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Quinase 8 Ativada por Mitógeno/genética , Células Mieloides/imunologia , Psoríase/induzido quimicamente , Psoríase/imunologia , Psoríase/patologia , Transdução de Sinais , Pele/imunologia , Pele/patologia , TranscriptomaRESUMO
Tumor-associated macrophages (TAMs) contribute to the maintenance of a strong immunosuppressive environment, supporting tumor progression and resistance to treatment. To date, the mechanisms that drive acquisition of these immunosuppressive features are still poorly defined. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme that catabolizes free heme. It displays important cytoprotective, antiinflammatory, and antioxidant properties. A growing body of evidence suggests that HO-1 may also promote tumor development. Herein, we show that HO-1 is highly expressed in monocytic cells in the tumor microenvironment (TME) once they differentiate into TAMs. Deletion of HO-1 in the myeloid compartment enhances the beneficial effects of a therapeutic antitumor vaccine by restoring CD8+ T cell proliferation and cytotoxicity. We further show that induction of HO-1 plays a major role in monocyte education by tumor cells by modulating their transcriptional and epigenetic programs. These results identify HO-1 as a valuable therapeutic target to reprogram the TME and synergize with current cancer therapies to facilitate antitumor response.
Assuntos
Heme Oxigenase-1/imunologia , Tolerância Imunológica , Proteínas de Membrana/imunologia , Neoplasias/imunologia , Microambiente Tumoral/imunologia , Macrófagos Associados a Tumor/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Heme Oxigenase-1/genética , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Neoplasias/genética , Microambiente Tumoral/genética , Macrófagos Associados a Tumor/patologiaRESUMO
RORγt-expressing Tregs form a specialized subset of intestinal CD4+ Foxp3+ cells which is essential to maintain gut homeostasis and tolerance to commensal microbiota. Recently, c-Maf emerged as a critical factor in the regulation of RORγt expression in Tregs. However, aside from c-Maf signaling, the signaling pathways involved in the differentiation of RORγt+ Tregs and their possible interplay with c-Maf in this process are largely unknown. We show that RORγt+ Treg development is controled by positive as well as negative signals. Along with c-Maf signaling, signals derived from a complex microbiota, as well as IL-6/STAT3- and TGF-ß-derived signals act in favor of RORγt+ Treg development. Ectopic expression of c-Maf did not rescue RORγt expression in STAT3-deficient Tregs, indicating the presence of additional effectors downstream of STAT3. Moreover, we show that an inflammatory IFN-γ/STAT1 signaling pathway acts as a negative regulator of RORγt+ Treg differentiation in a c-Maf independent fashion. These data thus argue for a complex integrative signaling network that finely tunes RORγt expression in Tregs. The finding that type 1 inflammation impedes RORγt+ Treg development even in the presence of an active IL-6/STAT3 pathway further suggests a dominant negative effect of STAT1 over STAT3 in this process.
Assuntos
Diferenciação Celular/genética , Diferenciação Celular/imunologia , Expressão Gênica , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Transdução de Sinais , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Imunofenotipagem , Camundongos , Camundongos Transgênicos , Proteínas Proto-Oncogênicas c-maf/genética , Proteínas Proto-Oncogênicas c-maf/metabolismo , Fator de Transcrição STAT3/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/citologia , Fator de Crescimento Transformador beta/metabolismoRESUMO
Memory CD8+ T cells have the ability to provide lifelong immunity against pathogens. Although memory features generally arise after challenge with a foreign antigen, naïve CD8 single positive (SP) thymocytes may acquire phenotypic and functional characteristics of memory cells in response to cytokines such as interleukin-4. This process is associated with the induction of the T-box transcription factor Eomesodermin (EOMES). However, the underlying molecular mechanisms remain ill-defined. Using epigenomic profiling, we show that these innate memory CD8SP cells acquire only a portion of the active enhancer repertoire of conventional memory cells. This reprograming is secondary to EOMES recruitment, mostly to RUNX3-bound enhancers. Furthermore, EOMES is found within chromatin-associated complexes containing BRG1 and promotes the recruitment of this chromatin remodelling factor. Also, the in vivo acquisition of EOMES-dependent program is BRG1-dependent. In conclusion, our results support a strong epigenetic basis for the EOMES-driven establishment of CD8+ T cell innate memory program.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Subunidade alfa 3 de Fator de Ligação ao Core/fisiologia , DNA Helicases/fisiologia , Epigênese Genética , Memória Imunológica , Proteínas Nucleares/fisiologia , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/fisiologia , Animais , Subunidade alfa 3 de Fator de Ligação ao Core/imunologia , Subunidade alfa 3 de Fator de Ligação ao Core/metabolismo , DNA Helicases/imunologia , DNA Helicases/metabolismo , Feminino , Perfilação da Expressão Gênica , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteínas Nucleares/imunologia , Proteínas Nucleares/metabolismo , Proteínas com Domínio T/genética , Fatores de Transcrição/imunologia , Fatores de Transcrição/metabolismoRESUMO
Monocytes play a major role in the defense against pathogens. They are rapidly mobilized to inflamed sites where they exert both proinflammatory and regulatory effector functions. It is still poorly understood how this dynamic and exceptionally plastic system is controlled at the molecular level. Herein, we evaluated the differentiation process that occurs in Ly6Chi monocytes during oral infection by Toxoplasma gondii. Flow cytometry and single-cell analysis revealed distinct activation status and gene expression profiles in the bone marrow, the spleen and the lamina propria of infected mice. We provide further evidence that acquisition of effector functions, such as the capacity to produce interleukin-27, is accompanied by distinct waves of epigenetic programming, highlighting a role for STAT1/IRF1 in the bone marrow and AP-1/NF-κB in the periphery. This work broadens our understanding of the molecular events that occur in vivo during monocyte differentiation in response to inflammatory cues.
Assuntos
Diferenciação Celular/imunologia , Monócitos/imunologia , Toxoplasma/imunologia , Toxoplasmose/imunologia , Toxoplasmose/parasitologia , Animais , Reprogramação Celular/genética , Biologia Computacional/métodos , Epigênese Genética , Perfilação da Expressão Gênica , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Monócitos/citologia , Monócitos/metabolismo , Análise de Célula Única , Toxoplasmose/genética , Toxoplasmose/metabolismoRESUMO
Cytotoxic CD4 (CD4CTX) T cells are emerging as an important component of antiviral and antitumor immunity, but the molecular basis of their development remains poorly understood. In the context of human cytomegalovirus infection, a significant proportion of CD4 T cells displays cytotoxic functions. We observed that the transcriptional program of these cells was enriched in CD8 T cell lineage genes despite the absence of ThPOK downregulation. We further show that establishment of CD4CTX-specific transcriptional and epigenetic programs occurred in a stepwise fashion along the Th1-differentiation pathway. In vitro, prolonged activation of naive CD4 T cells in presence of Th1 polarizing cytokines led to the acquisition of perforin-dependent cytotoxic activity. This process was dependent on the Th1 transcription factor Runx3 and was limited by the sustained expression of ThPOK. This work elucidates the molecular program of human CD4CTX T cells and identifies potential targets for immunotherapy against viral infections and cancer.