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1.
Nat Immunol ; 23(1): 86-98, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34845392

RESUMO

Ineffective antibody-mediated responses are a key characteristic of chronic viral infection. However, our understanding of the intrinsic mechanisms that drive this dysregulation are unclear. Here, we identify that targeting the epigenetic modifier BMI-1 in mice improves humoral responses to chronic lymphocytic choriomeningitis virus. BMI-1 was upregulated by germinal center B cells in chronic viral infection, correlating with changes to the accessible chromatin landscape, compared to acute infection. B cell-intrinsic deletion of Bmi1 accelerated viral clearance, reduced splenomegaly and restored splenic architecture. Deletion of Bmi1 restored c-Myc expression in B cells, concomitant with improved quality of antibody and coupled with reduced antibody-secreting cell numbers. Specifically, BMI-1-deficiency induced antibody with increased neutralizing capacity and enhanced antibody-dependent effector function. Using a small molecule inhibitor to murine BMI-1, we could deplete antibody-secreting cells and prohibit detrimental immune complex formation in vivo. This study defines BMI-1 as a crucial immune modifier that controls antibody-mediated responses in chronic infection.


Assuntos
Linfócitos B/imunologia , Imunidade Humoral/imunologia , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Complexo Repressor Polycomb 1/imunologia , Proteínas Proto-Oncogênicas/imunologia , Imunidade Adaptativa/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Feminino , Centro Germinativo/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
2.
Int J Mol Sci ; 21(24)2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33371448

RESUMO

CD8+ T cells play a pivotal role in clearing intracellular pathogens and combatting tumours. Upon infection, naïve CD8+ T cells differentiate into effector and memory cells, and this program is underscored by large-scale and coordinated changes in the chromatin architecture and gene expression. Importantly, recent evidence demonstrates that the epigenetic mechanisms that regulate the capacity for rapid effector function of memory T cells are shared by innate immune cells such as natural killer (NK) cells. Thus, it appears that the crucial difference between innate and adaptive immunity is the presence of the naïve state. This important distinction raises an intriguing new hypothesis, that the naïve state was evolutionary installed to restrain a default program of effector and memory differentiation in response to antigen recognition. We argue that the hallmark of adaptive T immunity is therefore the naïve program, which actively maintains CD8+ T cell quiescence until receipt of appropriate activation signals. In this review, we examine the mechanistic control of naïve CD8+ T cell quiescence and summarise the multiple levels of restraint imposed in naïve cells in to limit spontaneous and inappropriate activation. This includes epigenetic mechanisms and transcription factor (TF) regulation of gene expression, in addition to novel inhibitory receptors, abundance of RNA, and protein degradation.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular , Epigênese Genética , Regulação da Expressão Gênica , Memória Imunológica/imunologia , Fatores de Transcrição/metabolismo , Animais , Humanos , Fatores de Transcrição/genética
3.
J Infect Dis ; 219(11): 1841-1851, 2019 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-30615126

RESUMO

The resolution of Shigella flexneri infection-associated hyperinflammation is crucial for host survival. Using in vitro and in vivo models of shigellosis, we found that S. flexneri induces the expression of indoleamine 2,3-dioxygenase 1 (IDO1) through the nucleotide oligomerization domain 2 (NOD2) and epidermal growth factor receptor (EGFR) signaling pathway. Congruently, abrogation of NOD2 or EGFR compromises the ability of S. flexneri to induce IDO1 expression. We observed that the loss of IDO1 function in vivo exacerbates shigellosis by skewing the inflammatory cytokine response, disrupting colon epithelial barrier integrity and consequently limiting the host life-span. Interestingly, administration of recombinant EGF rescued mice from IDO1 inhibition-driven aggravated shigellosis by restoring the cytokine balance and subsequently restricting bacterial growth. This is the first study that underscores the direct implication of the NOD2-EGFR axis in IDO1 production and its crucial homeostatic contributions during shigellosis. Together, these findings reveal EGF as a potential therapeutic intervention for infectious diseases.


Assuntos
Citocinas/metabolismo , Disenteria Bacilar/imunologia , Receptores ErbB/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Shigella flexneri/imunologia , Transdução de Sinais , Animais , Disenteria Bacilar/microbiologia , Receptores ErbB/genética , Homeostase , Humanos , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Camundongos , Camundongos Endogâmicos BALB C , Células RAW 264.7
4.
J Biol Chem ; 290(44): 26576-86, 2015 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-26391398

RESUMO

Specific and coordinated regulation of innate immune receptor-driven signaling networks often determines the net outcome of the immune responses. Here, we investigated the cross-regulation of toll-like receptor (TLR)2 and nucleotide-binding oligomerization domain (NOD)2 pathways mediated by Ac2PIM, a tetra-acylated form of mycobacterial cell wall component and muramyl dipeptide (MDP), a peptidoglycan derivative respectively. While Ac2PIM treatment of macrophages compromised their ability to induce NOD2-dependent immunomodulators like cyclooxygenase (COX)-2, suppressor of cytokine signaling (SOCS)-3, and matrix metalloproteinase (MMP)-9, no change in the NOD2-responsive NO, TNF-α, VEGF-A, and IL-12 levels was observed. Further, genome-wide microRNA expression profiling identified Ac2PIM-responsive miR-150 and miR-143 to target NOD2 signaling adaptors, RIP2 and TAK1, respectively. Interestingly, Ac2PIM was found to activate the SRC-FAK-PYK2-CREB cascade via TLR2 to recruit CBP/P300 at the promoters of miR-150 and miR-143 and epigenetically induce their expression. Loss-of-function studies utilizing specific miRNA inhibitors establish that Ac2PIM, via the miRNAs, abrogate NOD2-induced PI3K-PKCδ-MAPK pathway to suppress ß-catenin-mediated expression of COX-2, SOCS-3, and MMP-9. Our investigation has thus underscored the negative regulatory role of Ac2PIM-TLR2 signaling on NOD2 pathway which could broaden our understanding on vaccine potential or adjuvant utilities of Ac2PIM and/or MDP.


Assuntos
MAP Quinase Quinase Quinases/metabolismo , Macrófagos/metabolismo , MicroRNAs/metabolismo , Proteína Adaptadora de Sinalização NOD2/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Acetilmuramil-Alanil-Isoglutamina/farmacologia , Animais , Linhagem Celular , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Ciclo-Oxigenase 2/farmacologia , Epigênese Genética , Imunidade Inata , Fatores Imunológicos/farmacologia , MAP Quinase Quinase Quinases/genética , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Proteínas Quinases Ativadas por Mitógeno , Óxido Nítrico/metabolismo , Proteína Adaptadora de Sinalização NOD2/genética , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Polissacarídeos Bacterianos/farmacologia , Ligação Proteica , Proteína Serina-Treonina Quinase 2 de Interação com Receptor , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Transdução de Sinais , Proteína 3 Supressora da Sinalização de Citocinas , Proteínas Supressoras da Sinalização de Citocina/genética , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Proteínas Supressoras da Sinalização de Citocina/farmacologia , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/metabolismo
6.
bioRxiv ; 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36909629

RESUMO

The differentiation of naïve CD8+ cytotoxic T lymphocytes (CTLs) into effector and memory states results in large scale changes in transcriptional and phenotypic profiles. Little is known about how large-scale changes in genome organisation reflect or underpin these transcriptional programs. We utilised Hi-C to map changes in the spatial organisation of long-range genome contacts within naïve, effector and memory virus-specific CD8+ T cells. We observed that the architecture of the naive CD8+ T cell genome was distinct from effector and memory genome configurations with extensive changes within discrete functional chromatin domains. However, deletion of the BACH2 or SATB1 transcription factors was sufficient to remodel the naïve chromatin architecture and engage transcriptional programs characteristic of differentiated cells. This suggests that the chromatin architecture within naïve CD8+ T cells is preconfigured to undergo autonomous remodelling upon activation, with key transcription factors restraining differentiation by actively enforcing the unique naïve chromatin state.

7.
Cell Rep ; 42(10): 113301, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37858463

RESUMO

The differentiation of naive CD8+ T lymphocytes into cytotoxic effector and memory CTL results in large-scale changes in transcriptional and phenotypic profiles. Little is known about how large-scale changes in genome organization underpin these transcriptional programs. We use Hi-C to map changes in the spatial organization of long-range genome contacts within naive, effector, and memory virus-specific CD8+ T cells. We observe that the architecture of the naive CD8+ T cell genome is distinct from effector and memory genome configurations, with extensive changes within discrete functional chromatin domains associated with effector/memory differentiation. Deletion of BACH2, or to a lesser extent, reducing SATB1 DNA binding, within naive CD8+ T cells results in a chromatin architecture more reminiscent of effector/memory states. This suggests that key transcription factors within naive CD8+ T cells act to restrain T cell differentiation by actively enforcing a unique naive chromatin state.


Assuntos
Linfócitos T CD8-Positivos , Cromatina , Diferenciação Celular , Fatores de Transcrição/genética , Memória Imunológica/genética
8.
Sci Rep ; 6: 24193, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27080341

RESUMO

CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) are exploited by mycobacteria to subvert the protective host immune responses. The Treg expansion in the periphery requires signaling by professional antigen presenting cells and in particularly dendritic cells (DC). However, precise molecular mechanisms by which mycobacteria instruct Treg expansion via DCs are not established. Here we demonstrate that mycobacteria-responsive sonic hedgehog (SHH) signaling in human DCs leads to programmed death ligand-1 (PD-L1) expression and cyclooxygenase (COX)-2-catalyzed prostaglandin E2 (PGE2) that orchestrate mycobacterial infection-induced expansion of Tregs. While SHH-responsive transcription factor GLI1 directly arbitrated COX-2 transcription, specific microRNAs, miR-324-5p and miR-338-5p, which target PD-L1 were downregulated by SHH signaling. Further, counter-regulatory roles of SHH and NOTCH1 signaling during mycobacterial-infection of human DCs was also evident. Together, our results establish that Mycobacterium directs a fine-balance of host signaling pathways and molecular regulators in human DCs to expand Tregs that favour immune evasion of the pathogen.


Assuntos
Antígeno B7-H1/metabolismo , Dinoprostona/metabolismo , Proteínas Hedgehog/metabolismo , Mycobacterium/imunologia , Transdução de Sinais , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Ciclo-Oxigenase 2/metabolismo , Humanos , Ativação Linfocitária/imunologia , Mycobacterium bovis/imunologia , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Receptores Notch/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Serina-Treonina Quinases TOR/metabolismo
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