RESUMO
Lymphatic transport of molecules and migration of myeloid cells to lymph nodes (LNs) continuously inform lymphocytes on changes in drained tissues. Here, using LN transplantation, single-cell RNA-seq, spectral flow cytometry, and a transgenic mouse model for photolabeling, we showed that tissue-derived unconventional T cells (UTCs) migrate via the lymphatic route to locally draining LNs. As each tissue harbored a distinct spectrum of UTCs with locally adapted differentiation states and distinct T cell receptor repertoires, every draining LN was thus populated by a distinctive tissue-determined mix of these lymphocytes. By making use of single UTC lineage-deficient mouse models, we found that UTCs functionally cooperated in interconnected units and generated and shaped characteristic innate and adaptive immune responses that differed between LNs that drained distinct tissues. Lymphatic migration of UTCs is, therefore, a key determinant of site-specific immunity initiated in distinct LNs with potential implications for vaccination strategies and immunotherapeutic approaches.
Assuntos
Linfonodos , Linfócitos T , Animais , Modelos Animais de Doenças , Imunidade , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos TRESUMO
Nitric oxide (NO) is an important antimicrobial effector but also prevents unnecessary tissue damage by shutting down the recruitment of monocyte-derived phagocytes. Intracellular pathogens such as Leishmania major can hijack these cells as a niche for replication. Thus, NO might exert containment by restricting the availability of the cellular niche required for efficient pathogen proliferation. However, such indirect modes of action remain to be established. By combining mathematical modeling with intravital 2-photon biosensors of pathogen viability and proliferation, we show that low L. major proliferation results not from direct NO impact on the pathogen but from reduced availability of proliferation-permissive host cells. Although inhibiting NO production increases recruitment of these cells, and thus pathogen proliferation, blocking cell recruitment uncouples the NO effect from pathogen proliferation. Therefore, NO fulfills two distinct functions for L. major containment: permitting direct killing and restricting the supply of proliferation-permissive host cells.
Assuntos
Leishmania major/fisiologia , Leishmaniose/imunologia , Macrófagos/imunologia , Óxido Nítrico/metabolismo , Animais , Processos de Crescimento Celular , Movimento Celular , Proliferação de Células , Modelos Animais de Doenças , Interações Hospedeiro-Patógeno , Humanos , Microscopia Intravital , Camundongos , Camundongos Endogâmicos C57BL , Modelos TeóricosRESUMO
Murine regulatory T (Treg) cells in tissues promote tissue homeostasis and regeneration. We sought to identify features that characterize human Treg cells with these functions in healthy tissues. Single-cell chromatin accessibility profiles of murine and human tissue Treg cells defined a conserved, microbiota-independent tissue-repair Treg signature with a prevailing footprint of the transcription factor BATF. This signature, combined with gene expression profiling and TCR fate mapping, identified a population of tissue-like Treg cells in human peripheral blood that expressed BATF, chemokine receptor CCR8 and HLA-DR. Human BATF+CCR8+ Treg cells from normal skin and adipose tissue shared features with nonlymphoid T follicular helper-like (Tfh-like) cells, and induction of a Tfh-like differentiation program in naive human Treg cells partially recapitulated tissue Treg regenerative characteristics, including wound healing potential. Human BATF+CCR8+ Treg cells from healthy tissue share features with tumor-resident Treg cells, highlighting the importance of understanding the context-specific functions of these cells.
Assuntos
Cromatina/imunologia , Linfócitos T Reguladores/imunologia , Cicatrização/imunologia , Adulto , Animais , Fatores de Transcrição de Zíper de Leucina Básica/imunologia , Diferenciação Celular/imunologia , Linhagem Celular , Feminino , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/imunologia , Células HaCaT , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptores CCR8/imunologia , Células T Auxiliares Foliculares/imunologiaRESUMO
Roquin proteins preclude spontaneous T cell activation and aberrant differentiation of T follicular helper (Tfh) or T helper 17 (Th17) cells. Here we showed that deletion of Roquin-encoding alleles specifically in regulatory T (Treg) cells also caused the activation of conventional T cells. Roquin-deficient Treg cells downregulated CD25, acquired a follicular Treg (Tfr) cell phenotype, and suppressed germinal center reactions but could not protect from colitis. Roquin inhibited the PI3K-mTOR signaling pathway by upregulation of Pten through interfering with miR-17â¼92 binding to an overlapping cis-element in the Pten 3' UTR, and downregulated the Foxo1-specific E3 ubiquitin ligase Itch. Loss of Roquin enhanced Akt-mTOR signaling and protein synthesis, whereas inhibition of PI3K or mTOR in Roquin-deficient T cells corrected enhanced Tfh and Th17 or reduced iTreg cell differentiation. Thereby, Roquin-mediated control of PI3K-mTOR signaling prevents autoimmunity by restraining activation and differentiation of conventional T cells and specialization of Treg cells.
Assuntos
Colite/imunologia , Fosfatidilinositol 3-Quinases/imunologia , Proteínas Repressoras/imunologia , Serina-Treonina Quinases TOR/imunologia , Ubiquitina-Proteína Ligases/imunologia , Animais , Linfócitos B/imunologia , Linfócitos B/patologia , Diferenciação Celular , Colite/genética , Colite/patologia , Modelos Animais de Doenças , Feminino , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/imunologia , Regulação da Expressão Gênica , Centro Germinativo/imunologia , Centro Germinativo/patologia , Subunidade alfa de Receptor de Interleucina-2/genética , Subunidade alfa de Receptor de Interleucina-2/imunologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , MicroRNAs/genética , MicroRNAs/imunologia , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/imunologia , Fosfatidilinositol 3-Quinases/genética , Cultura Primária de Células , Proteínas Repressoras/deficiência , Proteínas Repressoras/genética , Transdução de Sinais , Baço/imunologia , Baço/patologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/patologia , Serina-Treonina Quinases TOR/genética , Células Th17/imunologia , Células Th17/patologia , Ubiquitina-Proteína Ligases/deficiência , Ubiquitina-Proteína Ligases/genéticaRESUMO
Mucosal barrier integrity and pathogen clearance is a complex process influenced by both Th17 and Treg cells. Previously, we had described the DNA methylation profile of Th17 cells and identified Zinc finger protein (Zfp)362 to be uniquely demethylated. Here, we generated Zfp362-/- mice to unravel the role of Zfp362 for Th17 cell biology. Zfp362-/- mice appeared clinically normal, showed no phenotypic alterations in the T-cell compartment, and upon colonization with segmented filamentous bacteria, no effect of Zfp362 deficiency on Th17 cell differentiation was observed. By contrast, Zfp362 deletion resulted in increased frequencies of colonic Foxp3+ Treg cells and IL-10+ and RORγt+ Treg cell subsets in mesenteric lymph nodes. Adoptive transfer of naïve CD4+ T cells from Zfp362-/- mice into Rag2-/- mice resulted in a significantly lower weight loss when compared with controls receiving cells from Zfp362+/+ littermates. However, this attenuated weight loss did not correlate with alterations of Th17 cells but instead was associated with an increase of effector Treg cells in mesenteric lymph nodes. Together, these results suggest that Zfp362 plays an important role in promoting colonic inflammation; however, this function is derived from constraining the effector function of Treg cells rather than directly promoting Th17 cell differentiation.
Assuntos
Linfócitos T Reguladores , Células Th17 , Camundongos , Animais , Linfócitos T Reguladores/metabolismo , Células Th17/metabolismo , Diferenciação Celular , Inflamação/metabolismo , Redução de Peso , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismoRESUMO
BACKGROUND: Theiler's murine encephalomyelitis virus (TMEV) is a single-stranded RNA virus that causes encephalitis followed by chronic demyelination in SJL mice and spontaneous seizures in C57BL/6 mice. Since earlier studies indicated a critical role of type I interferon (IFN-I) signaling in the control of viral replication in the central nervous system (CNS), mouse strain-specific differences in pathways induced by the IFN-I receptor (IFNAR) might determine the outcome of TMEV infection. METHODS: Data of RNA-seq analysis and immunohistochemistry were used to compare the gene and protein expression of IFN-I signaling pathway members between mock- and TMEV-infected SJL and C57BL/6 mice at 4, 7 and 14 days post-infection (dpi). To address the impact of IFNAR signaling in selected brain-resident cell types, conditional knockout mice with an IFNAR deficiency in cells of the neuroectodermal lineage (NesCre±IFNARfl/fl), neurons (Syn1Cre±IFNARfl/fl), astrocytes (GFAPCre±IFNARfl/fl), and microglia (Sall1CreER±IFNARfl/fl) on a C57BL/6 background were tested. PCR and an immunoassay were used to quantify TMEV RNA and cytokine and chemokine expression in their brain at 4 dpi. RESULTS: RNA-seq analysis revealed upregulation of most ISGs in SJL and C57BL/6 mice, but Ifi202b mRNA transcripts were only increased in SJL and Trim12a only in C57BL/6 mice. Immunohistochemistry showed minor differences in ISG expression (ISG15, OAS, PKR) between both mouse strains. While all immunocompetent Cre-negative control mice and the majority of mice with IFNAR deficiency in neurons or microglia survived until 14 dpi, lack of IFNAR expression in all cells (IFNAR-/-), neuroectodermal cells, or astrocytes induced lethal disease in most of the analyzed mice, which was associated with unrestricted viral replication. NesCre±IFNARfl/fl mice showed more Ifnb1, Tnfa, Il6, Il10, Il12b and Ifng mRNA transcripts than Cre-/-IFNARfl/fl mice. IFNAR-/- mice also demonstrated increased IFN-α, IFN-ß, IL1-ß, IL-6, and CXCL-1 protein levels, which highly correlated with viral load. CONCLUSIONS: Ifi202b and Trim12a expression levels likely contribute to mouse strain-specific susceptibility to TMEV-induced CNS lesions. Restriction of viral replication is strongly dependent on IFNAR signaling of neuroectodermal cells, which also controls the expression of key pro- and anti-inflammatory cytokines during viral brain infection.
Assuntos
Theilovirus , Animais , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais , Encéfalo , Sistema Nervoso Central , Citocinas , AnticorposRESUMO
Conventional dendritic cells (cDCs) arise from committed precursor dendritic cells (pre-DCs) in the bone marrow that continuously seed the periphery. Pre-DCs and other upstream progenitors proliferate and mature in response to Fms-related receptor tyrosine kinase 3 ligand, which is considered the key cytokine for cDC development. However, other cytokines such as stem cell factor and colony-stimulating factor 1 (CSF1) were also shown to induce pre-DC maturation into DC-like cells. Yet, it is still only incompletely understood which cells contribute to cDC development once pre-DCs arrive in peripheral tissues. Here, we analysed the impact of lymph node (LN) fibroblastic stromal cells (FSCs) on the maturation of pre-DCs into cDC-like cells. We could demonstrate that ex vivo isolated LN FSCs co-cultured with pre-DCs induce precursor maturation into DC-like cells, which were capable of efficiently promoting the proliferation of naïve CD4+ T cells. Interestingly, FSCs isolated from distinct LNs induced DC-like cells with highly comparable transcriptomes, characterized by the expression of signature genes of both ex vivo isolated DCs and macrophages. Finally, by performing supplementation and receptor blocking studies, we could demonstrate that CSF1 is a driving factor for LN FSC-mediated pre-DC maturation into DC-like cells. In summary, we could identify CSF1 as a stromal cell-derived factor that has the potential to support the maturation of pre-DCs into cDC-like cells within secondary lymphoid organs.
Assuntos
Células Dendríticas , Fator Estimulador de Colônias de Macrófagos , Diferenciação Celular , Células Cultivadas , Citocinas/metabolismo , Células Dendríticas/metabolismo , Linfonodos , Fator Estimulador de Colônias de Macrófagos/metabolismo , Fator Estimulador de Colônias de Macrófagos/farmacologia , Células Estromais , Linfócitos TRESUMO
Foxp3+ Treg cells, which are crucial for maintenance of self-tolerance, mainly develop within the thymus, where they arise from CD25+ Foxp3- or CD25- Foxp3+ Treg cell precursors. Although it is known that infections can cause transient thymic involution, the impact of infection-induced thymus atrophy on thymic Treg (tTreg) cell development is unknown. Here, we infected mice with influenza A virus (IAV) and studied thymocyte population dynamics post infection. IAV infection caused a massive, but transient thymic involution, dominated by a loss of CD4+ CD8+ double-positive (DP) thymocytes, which was accompanied by a significant increase in the frequency of CD25+ Foxp3+ tTreg cells. Differential apoptosis susceptibility could be experimentally excluded as a reason for the relative tTreg cell increase, and mathematical modeling suggested that enhanced tTreg cell generation cannot explain the increased frequency of tTreg cells. Yet, an increased death of DP thymocytes and augmented exit of single-positive (SP) thymocytes was suggested to be causative. Interestingly, IAV-induced thymus atrophy resulted in a significantly reduced T-cell receptor (TCR) repertoire diversity of newly produced tTreg cells. Taken together, IAV-induced thymus atrophy is substantially altering the dynamics of major thymocyte populations, finally resulting in a relative increase of tTreg cells with an altered TCR repertoire.
Assuntos
Vírus da Influenza A/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/patologia , Linfócitos T Reguladores/imunologia , Timo/imunologia , Timo/patologia , Animais , Atrofia , Biomarcadores , Sobrevivência Celular/imunologia , Imunofenotipagem , Ativação Linfocitária/imunologia , Contagem de Linfócitos , Camundongos , Infecções por Orthomyxoviridae/virologia , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/metabolismo , Timócitos/imunologia , Timócitos/metabolismoRESUMO
The interdependence of selective cues during development of regulatory T cells (Treg cells) in the thymus and their suppressive function remains incompletely understood. Here, we analyzed this interdependence by taking advantage of highly dynamic changes in expression of microRNA 181 family members miR-181a-1 and miR-181b-1 (miR-181a/b-1) during late T-cell development with very high levels of expression during thymocyte selection, followed by massive down-regulation in the periphery. Loss of miR-181a/b-1 resulted in inefficient de novo generation of Treg cells in the thymus but simultaneously permitted homeostatic expansion in the periphery in the absence of competition. Modulation of T-cell receptor (TCR) signal strength in vivo indicated that miR-181a/b-1 controlled Treg-cell formation via establishing adequate signaling thresholds. Unexpectedly, miR-181a/b-1-deficient Treg cells displayed elevated suppressive capacity in vivo, in line with elevated levels of cytotoxic T-lymphocyte-associated 4 (CTLA-4) protein, but not mRNA, in thymic and peripheral Treg cells. Therefore, we propose that intrathymic miR-181a/b-1 controls development of Treg cells and imposes a developmental legacy on their peripheral function.
Assuntos
MicroRNAs/metabolismo , Linfócitos T Reguladores/metabolismo , Animais , Citometria de Fluxo , Camundongos , Camundongos Knockout , MicroRNAs/genética , Microscopia Confocal , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Timócitos/metabolismoRESUMO
The effective priming of adaptive immune responses depends on the precise dispatching of lymphocytes and antigens into and within lymph nodes (LNs), which are strategically dispersed throughout the body. Over the past decade, a growing body of evidence has advanced our understanding of lymph node stromal cells (LNSCs) from viewing them as mere accessory cells to seeing them as critical cellular players for the modulation of adaptive immune responses. In this review, we summarize current advances on the pivotal roles that LNSCs play in orchestrating adaptive immune responses during homeostasis and infection, and highlight the imprinting of location-specific information by micro-environmental cues into LNSCs, thereby tailoring tissue-specific immune responses.
Assuntos
Especialização , Células Estromais , Homeostase , Imunidade , LinfonodosRESUMO
The emerging notion of environment-induced reprogramming of Foxp3(+) regulatory T (Treg) cells into helper T (Th) cells remains controversial. By genetic fate mapping or adoptive transfers, we have identified a minor population of nonregulatory Foxp3(+) T cells exhibiting promiscuous and transient Foxp3 expression, which gave rise to Foxp3(-) ("exFoxp3") Th cells and selectively accumulated in inflammatory cytokine milieus or in lymphopenic environments including those in early ontogeny. In contrast, Treg cells did not undergo reprogramming under those conditions irrespective of their thymic or peripheral origins. Moreover, although a few Treg cells transiently lose Foxp3 expression, such "latent" Treg cells retained their memory and robustly re-expressed Foxp3 and suppressive function upon activation. This study establishes that Treg cells constitute a stable cell lineage, whose committed state in a changing environment is ensured by DNA demethylation of the Foxp3 locus irrespectively of ongoing Foxp3 expression.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Antígenos CD2/genética , Antígenos CD2/metabolismo , Linfócitos T CD4-Positivos/citologia , Diferenciação Celular , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Metilação de DNA , Epigênese Genética , Fatores de Transcrição Forkhead/genética , Expressão Gênica , Humanos , Memória Imunológica , Técnicas In Vitro , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Ativação Linfocitária , Linfopenia/imunologia , Linfopenia/metabolismo , Linfopenia/patologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/citologiaRESUMO
Forkhead box P3 positive (Foxp3(+)) regulatory T (Treg) cells suppress immune responses and regulate peripheral tolerance. Here we show that the atypical inhibitor of NFκB (IκB) IκB(NS) drives Foxp3 expression via association with the promoter and the conserved noncoding sequence 3 (CNS3) of the Foxp3 locus. Consequently, IκB(NS) deficiency leads to a substantial reduction of Foxp3(+) Treg cells in vivo and impaired Foxp3 induction upon transforming growth factor-ß (TGF-ß) treatment in vitro. Moreover, fewer Foxp3(+) Treg cells developed from IκB(NS)-deficient CD25(-)CD4(+) T cells adoptively transferred into immunodeficient recipients. Importantly, IκB(NS) was required for the transition of immature GITR(+)CD25(+)Foxp3(-) thymic Treg cell precursors into Foxp3(+) cells. In contrast to mice lacking c-Rel or Carma1, IκB(NS)-deficient mice do not show reduced Treg precursor cells. Our results demonstrate that IκB(NS) critically regulates Treg cell development in the thymus and during gut inflammation, indicating that strategies targeting IκB(NS) could modulate the Treg cell compartment.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , Proteínas I-kappa B/metabolismo , Proteínas/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Transferência Adotiva , Animais , Apoptose , Diferenciação Celular/imunologia , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica , Proteínas I-kappa B/deficiência , Proteínas I-kappa B/genética , Imunomodulação , Peptídeos e Proteínas de Sinalização Intracelular , Ativação Linfocitária/imunologia , Masculino , Camundongos , Camundongos Transgênicos , Subunidade p50 de NF-kappa B/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Proto-Oncogênicas c-rel/metabolismo , Linfócitos T Reguladores/efeitos dos fármacos , Fator de Crescimento Transformador beta/farmacologiaRESUMO
Regulatory T (Treg) cells, driven by the Foxp3 transcription factor, are responsible for limiting autoimmunity and chronic inflammation. We showed that a well-characterized Foxp3(gfp) reporter mouse, which expresses an N-terminal GFP-Foxp3 fusion protein, is a hypomorph that causes profoundly accelerated autoimmune diabetes on a NOD background. Although natural Treg cell development and in vitro function are not markedly altered in Foxp3(gfp) NOD and C57BL/6 mice, Treg cell function in inflammatory environments was perturbed and TGF-ß-induced Treg cell development was reduced. Foxp3(gfp) was unable to interact with the histone acetyltransferase Tip60, the histone deacetylase HDAC7, and the Ikaros family zinc finger 4, Eos, which led to reduced Foxp3 acetylation and enhanced K48-linked polyubiquitylation. Collectively this results in an altered transcriptional landscape and reduced Foxp3-mediated gene repression, notably at the hallmark IL-2 promoter. Loss of controlled Foxp3-driven epigenetic modification leads to Treg cell insufficiency that enables autoimmunity in susceptible environments.
Assuntos
Fatores de Transcrição Forkhead/imunologia , Fatores de Transcrição Forkhead/metabolismo , Linfócitos T Reguladores/imunologia , Fatores de Transcrição/imunologia , Fatores de Transcrição/metabolismo , Acetilação , Animais , Autoimunidade/genética , Autoimunidade/imunologia , Proteínas de Transporte/genética , Proteínas de Transporte/imunologia , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Epigênese Genética , Fatores de Transcrição Forkhead/genética , Histona Acetiltransferases/genética , Histona Acetiltransferases/imunologia , Histona Acetiltransferases/metabolismo , Histona Desacetilases/genética , Histona Desacetilases/imunologia , Histona Desacetilases/metabolismo , Interleucina-2/genética , Interleucina-2/imunologia , Interleucina-2/metabolismo , Lisina Acetiltransferase 5 , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/imunologia , Proteínas do Tecido Nervoso/metabolismo , Regiões Promotoras Genéticas , Linfócitos T Reguladores/metabolismo , Transativadores/genética , Transativadores/imunologia , Transativadores/metabolismo , Fatores de Transcrição/genética , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/imunologia , Fator de Crescimento Transformador beta/metabolismoRESUMO
The transcription factor Foxp3 is essential for the development of regulatory T (Treg) cells, yet its expression is insufficient for establishing the Treg cell lineage. Here we showed that Treg cell development was achieved by the combination of two independent processes, i.e., the expression of Foxp3 and the establishment of Treg cell-specific CpG hypomethylation pattern. Both events were induced by T cell receptor stimulation. The Treg cell-type CpG hypomethylation began in the thymus and continued to proceed in the periphery and could be fully established without Foxp3. The hypomethylation was required for Foxp3(+) T cells to acquire Treg cell-type gene expression, lineage stability, and full suppressive activity. Thus, those T cells in which the two events have concurrently occurred are developmentally set into the Treg cell lineage. This model explains how Treg cell fate and plasticity is controlled and can be exploited to generate functionally stable Treg cells.
Assuntos
Fatores de Transcrição Forkhead/biossíntese , Fatores de Transcrição Forkhead/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Animais , Metilação de DNA , Epigênese Genética , Fatores de Transcrição Forkhead/genética , Expressão Gênica , Histonas/genética , Histonas/imunologia , Histonas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Reguladores/metabolismo , Timo/imunologia , Timo/metabolismoRESUMO
During influenza A virus (IAV) infections, CD4+ T cell responses within infected lungs mainly involve T helper 1 (Th1) and regulatory T cells (Tregs). Th1-mediated responses favor the co-expression of T-box transcription factor 21 (T-bet) in Foxp3+ Tregs, enabling the efficient Treg control of Th1 responses in infected tissues. So far, the exact accumulation kinetics of T cell subsets in the lungs and lung-draining lymph nodes (dLN) of IAV-infected mice is incompletely understood, and the epigenetic signature of Tregs accumulating in infected lungs has not been investigated. Here, we report that the total T cell and the two-step Treg accumulation in IAV-infected lungs is transient, whereas the change in the ratio of CD4+ to CD8+ T cells is more durable. Within lungs, the frequency of Tregs co-expressing T-bet is steadily, yet transiently, increasing with a peak at Day 7 post-infection. Interestingly, T-bet+ Tregs accumulating in IAV-infected lungs displayed a strongly demethylated Tbx21 locus, similarly as in T-bet+ conventional T cells, and a fully demethylated Treg-specific demethylated region (TSDR) within the Foxp3 locus. In summary, our data suggest that T-bet+ but not T-bet- Tregs are epigenetically stabilized during IAV-induced infection in the lung.
Assuntos
Linfócitos T CD8-Positivos/virologia , Epigênese Genética , Fatores de Transcrição Forkhead/metabolismo , Pulmão/virologia , Infecções por Orthomyxoviridae/virologia , Proteínas com Domínio T/metabolismo , Linfócitos T Reguladores/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Fatores de Transcrição Forkhead/genética , Vírus da Influenza A/fisiologia , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/patologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/metabolismo , Infecções por Orthomyxoviridae/patologia , Proteínas com Domínio T/genéticaRESUMO
BACKGROUND: Transmaternal exposure to tobacco, microbes, nutrients, and other environmental factors shapes the fetal immune system through epigenetic processes. The gastric microbe Helicobacter pylori represents an ancestral constituent of the human microbiota that causes gastric disorders on the one hand and is inversely associated with allergies and chronic inflammatory conditions on the other. OBJECTIVE: Here we investigate the consequences of transmaternal exposure to H pylori in utero and/or during lactation for susceptibility to viral and bacterial infection, predisposition to allergic airway inflammation, and development of immune cell populations in the lungs and lymphoid organs. METHODS: We use experimental models of house dust mite- or ovalbumin-induced airway inflammation and influenza A virus or Citrobacter rodentium infection along with metagenomics analyses, multicolor flow cytometry, and bisulfite pyrosequencing, to study the effects of H pylori on allergy severity and immunologic and microbiome correlates thereof. RESULTS: Perinatal exposure to H pylori extract or its immunomodulator vacuolating cytotoxin confers robust protective effects against allergic airway inflammation not only in first- but also second-generation offspring but does not increase susceptibility to viral or bacterial infection. Immune correlates of allergy protection include skewing of regulatory over effector T cells, expansion of regulatory T-cell subsets expressing CXCR3 or retinoic acid-related orphan receptor γt, and demethylation of the forkhead box P3 (FOXP3) locus. The composition and diversity of the gastrointestinal microbiota is measurably affected by perinatal H pylori exposure. CONCLUSION: We conclude that exposure to H pylori has consequences not only for the carrier but also for subsequent generations that can be exploited for interventional purposes.
Assuntos
Infecções por Helicobacter/imunologia , Efeitos Tardios da Exposição Pré-Natal/imunologia , Efeitos Tardios da Exposição Pré-Natal/microbiologia , Hipersensibilidade Respiratória/imunologia , Hipersensibilidade Respiratória/microbiologia , Linfócitos T Reguladores/imunologia , Animais , Feminino , Tolerância Imunológica/imunologia , Camundongos Endogâmicos C57BL , GravidezRESUMO
Yersinia pseudotuberculosis is a Gram-negative bacterium and zoonotic pathogen responsible for a wide range of diseases, ranging from mild diarrhea, enterocolitis, lymphatic adenitis to persistent local inflammation. The Y. pseudotuberculosis invasin D (InvD) molecule belongs to the invasin (InvA)-type autotransporter proteins, but its structure and function remain unknown. In this study, we present the first crystal structure of InvD, analyzed its expression and function in a murine infection model, and identified its target molecule in the host. We found that InvD is induced at 37 °C and expressed in vivo 2-4 days after infection, indicating that InvD is a virulence factor. During infection, InvD was expressed in all parts of the intestinal tract, but not in deeper lymphoid tissues. The crystal structure of the C-terminal adhesion domain of InvD revealed a distinct Ig-related fold that, apart from the canonical ß-sheets, comprises various modifications of and insertions into the Ig-core structure. We identified the Fab fragment of host-derived IgG/IgA antibodies as the target of the adhesion domain. Phage display panning and flow cytometry data further revealed that InvD exhibits a preferential binding specificity toward antibodies with VH3/VK1 variable domains and that it is specifically recruited to a subset of B cells. This finding suggests that InvD modulates Ig functions in the intestine and affects direct interactions with a subset of cell surface-exposed B-cell receptors. In summary, our results provide extensive insights into the structure of InvD and its specific interaction with the target molecule in the host.
Assuntos
Adesinas Bacterianas/metabolismo , Anticorpos/metabolismo , Fragmentos Fab das Imunoglobulinas/metabolismo , Intestinos/microbiologia , Infecções por Yersinia pseudotuberculosis/microbiologia , Yersinia pseudotuberculosis/patogenicidade , Adesinas Bacterianas/química , Sequência de Aminoácidos , Animais , Anticorpos/imunologia , Aderência Bacteriana , Feminino , Fragmentos Fab das Imunoglobulinas/imunologia , Intestinos/imunologia , Intestinos/patologia , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Conformação Proteica , Homologia de Sequência , Virulência , Yersinia pseudotuberculosis/imunologia , Infecções por Yersinia pseudotuberculosis/metabolismo , Infecções por Yersinia pseudotuberculosis/patologiaRESUMO
Foxp3-expressing regulatory T cells (Tregs) are essential regulators of immune homeostasis and, thus, are prime targets for therapeutic interventions of diseases such as cancer and autoimmunity. c-REL and IκBNS are important regulators of Foxp3 induction in Treg precursors upon γ-chain cytokine stimulation. In c-REL/IκBNS double-deficient mice, Treg numbers were dramatically reduced, indicating that together, c-REL and IκBNS are pivotal for Treg development. However, despite the highly reduced Treg compartment, double-deficient mice did not develop autoimmunity even when aged to more than 1 y, suggesting that c-REL and IκBNS are required for T cell effector function as well. Analyzing Treg development in more detail, we identified a CD122+ subset within the CD25-Foxp3- precursor population, which gave rise to classical CD25+Foxp3- Treg precursors. Importantly, c-REL, but not IκBNS, controlled the generation of classical CD25+Foxp3- precursors via direct binding to the Cd25 locus. Thus, we propose that CD4+GITR+CD122+CD25-Foxp3- cells represent a Treg pre-precursor population, whose transition into Treg precursors is mediated via c-REL.
Assuntos
Diferenciação Celular , Fatores de Transcrição Forkhead/metabolismo , Inibidor de NF-kappaB alfa/metabolismo , Proteínas Proto-Oncogênicas c-rel/metabolismo , Linfócitos T Reguladores/fisiologia , Animais , Autoimunidade , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica , Subunidade alfa de Receptor de Interleucina-2/imunologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Subunidade beta de Receptor de Interleucina-2/genética , Subunidade beta de Receptor de Interleucina-2/imunologia , Camundongos , Inibidor de NF-kappaB alfa/deficiência , Inibidor de NF-kappaB alfa/genética , Ligação Proteica , Proteínas Proto-Oncogênicas c-rel/deficiência , Proteínas Proto-Oncogênicas c-rel/genética , Subpopulações de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologiaRESUMO
Regulatory T cells (Treg cells) present a unique T-cell lineage that plays a key role for the initiation and maintenance of immunological tolerance. Treg cells are characterized by the expression of the forkhead box transcription factor Foxp3, which acts as a lineage-specifying factor and determines the unique properties of these immunosuppressive cells. Work over the past few years has shown that well-defined and precisely controlled events on transcriptional and epigenetic level are required to ensure stable expression of Foxp3 in Treg cells. More recent work suggested that in addition to stable Foxp3 expression, epigenetic modifications of Treg-cell specific genes contribute to the unique phenotype of Treg cells by imprinting their transcriptional program and stabilizing the expression of molecules being essential for the suppressive properties of Treg cells. In this review, we will highlight how Foxp3 expression itself is epigenetically and transcriptionally controlled, how the Treg-cell specific epigenetic signature is achieved, how Foxp3 as transcription factor influences the gene expression programs in Treg cells and how unique properties of Treg-cell subsets are defined by other transcription factors.