Rel/NF-κB Transcription Factors Emerged at the Onset of Opisthokonts.
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ABSTRACT:
SUBMITTER: Leger MM
PROVIDER: S-EPMC8763368 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The Rel proteins of the NF-κB complex comprise one of the most investigated transcription factor families, forming a variety of hetero- or homodimers. Nevertheless, very little is known about the fundamental kinetics of NF-κB complex assembly, or the inter-conversion potential of dimerised Rel subunits. Here, we examined an unexplored aspect of NF-κB dynamics, focusing on the dissociation and reassociation of the canonical p50 and p65 Rel subunits and their ability to form new hetero- or homodimers. We employed a soluble expression system to enable the facile production of NF-κB Rel subunits, and verified these proteins display canonical NF-κB nucleic acid binding properties. Using a combination of biophysical techniques, we demonstrated that, at physiological temperatures, homodimeric Rel complexes routinely exchange subunits with a half-life of less than 10 min. In contrast, we found a dramatic preference for the formation of the p50/p65 heterodimer, which demonstrated a kinetic stability of at least an order of magnitude greater than either homodimer. These results suggest that specific DNA targets of either the p50 or p65 homodimers can only be targeted when these subunits are expressed exclusively, or with the intervention of additional post-translational modifications. Together, this work implies a new model of how cells can modulate NF-κB activity by fine-tuning the relative proportions of the p50 and p65 proteins, as well as their time of expression. This work thus provides a new quantitative interpretation of Rel dimer distribution in the cell, particularly for those who are developing mathematical models of NF-κB activity.
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Project description:The NF-κB family of dimeric transcription factors regulates transcription by selectively binding to DNA response elements present within promoters or enhancers of target genes. The DNA response elements, collectively known as κB sites or κB DNA, share the consensus 5'-GGGRNNNYCC-3' (where R, Y and N are purine, pyrimidine and any nucleotide base, respectively). In addition, several DNA sequences that deviate significantly from the consensus have been shown to accommodate binding by NF-κB dimers. X-ray crystal structures of NF-κB in complex with diverse κB DNA have helped elucidate the chemical principles that underlie target selection in vitro. However, NF-κB dimers encounter additional impediments to selective DNA binding in vivo. Work carried out during the past decades has identified some of the barriers to sequence selective DNA target binding within the context of chromatin and suggests possible mechanisms by which NF-κB might overcome these obstacles. In this review, we first highlight structural features of NF-κB:DNA complexes and how distinctive features of NF-κB proteins and DNA sequences contribute to specific complex formation. We then discuss how native NF-κB dimers identify DNA binding targets in the nucleus with support from additional factors and how post-translational modifications enable NF-κB to selectively bind κB sites in vivo.
| S-EPMC6821244 | biostudies-literature
Project description:Signaling through the canonical nuclear factor-κB (NF-κB) pathway is critical for the generation and maintenance of mature B cells and for antigen-dependent B-cell activation. c-REL (rel) and RELA (rela) are the downstream transcriptional activators of the canonical NF-κB pathway. Studies of B cells derived from constitutional rel knockout mice and chimeric mice repopulated with rela-/- fetal liver cells provided evidence that the subunits can have distinct roles during B-cell development. However, the B cell-intrinsic functions of c-REL and RELA during B-cell generation and antigen-dependent B-cell activation have not been determined in vivo. To clarify this issue, we crossed mice with conditional rel and rela alleles individually or in combination to mice that express Cre-recombinase in B cells. We here report that, whereas single deletion of rel or rela did not impair mature B-cell generation and maintenance, their simultaneous deletion led to a dramatic reduction of follicular and marginal zone B cells. Upon T cell-dependent immunization, B cell-specific deletion of the c-REL subunit alone abrogated the formation of germinal centers (GCs), whereas rela deletion did not affect GC formation. T-independent responses were strongly impaired in mice with B cell-specific deletion of rel, and only modestly in mice with RELA-deficient B cells. Our findings identify differential requirements for the canonical NF-κB subunits c-REL and RELA at distinct stages of mature B-cell development. The subunits are jointly required for the generation of mature B cells. During antigen-dependent B-cell activation, c-REL is the critical subunit required for the initiation of the GC reaction and for optimal T-independent antibody responses, with RELA being largely dispensable at this stage.
| S-EPMC5360551 | biostudies-literature
Project description:Cardiac remodeling and hypertrophy are the pathological consequences of cardiovascular disease and are correlated with its associated mortality. Activity of the transcription factor NF-κB is increased in the diseased heart; however, our present understanding of how the individual subunits contribute to cardiovascular disease is limited. We assign a new role for the c-Rel subunit as a stimulator of cardiac hypertrophy and fibrosis. We discovered that c-Rel-deficient mice have smaller hearts at birth, as well as during adulthood, and are protected from developing cardiac hypertrophy and fibrosis after chronic angiotensin infusion. Results of both gene expression and cross-linked chromatin immunoprecipitation assay analyses identified transcriptional activators of hypertrophy, myocyte enhancer family, Gata4, and Tbx proteins as Rel gene targets. We suggest that the p50 subunit could limit the prohypertrophic actions of c-Rel in the normal heart, because p50 overexpression in H9c2 cells repressed c-Rel levels and the absence of cardiac p50 was associated with increases in both c-Rel levels and cardiac hypertrophy. We report for the first time that c-Rel is highly expressed and confined to the nuclei of diseased adult human hearts but is restricted to the cytoplasm of normal cardiac tissues. We conclude that c-Rel-dependent signaling is critical for both cardiac remodeling and hypertrophy. Targeting its activities could offer a novel therapeutic strategy to limit the effects of cardiac disease.
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Project description:This SuperSeries is composed of the SubSeries listed below.
2024-03-28 | GSE239704 | GEO
Project description:This study tested the hypothesis that transcription of immediate early genes is inhibited in T cells activated in μg. Immunosuppression during spaceflight is a major barrier to safe, long-term human space habitation and travel. The goals of these experiments were to prove that μg was the cause of impaired T cell activation during spaceflight, as well as understand the mechanisms controlling early T cell activation. T cells from four human donors were stimulated with Con A and anti-CD28 on board the ISS. An on-board centrifuge was used to generate a 1g simultaneous control to isolate the effects of μg from other variables of spaceflight. Microarray expression analysis after 1.5 h of activation demonstrated that μg- and 1g-activated T cells had distinct patterns of global gene expression and identified 47 genes that were significantly, differentially down-regulated in μg. Importantly, several key immediate early genes were inhibited in μg. In particular, transactivation of Rel/NF-κB, CREB, and SRF gene targets were down-regulated. Expression of cREL gene targets were significantly inhibited, and transcription of cREL itself was reduced significantly in μg and upon anti-CD3/anti-CD28 stimulation in simulated μg. Analysis of gene connectivity indicated that the TNF pathway is a major early downstream effector pathway inhibited in μg and may lead to ineffective proinflammatory host defenses against infectious pathogens during spaceflight. Results from these experiments indicate that μg was the causative factor for impaired T cell activation during spaceflight by inhibiting transactivation of key immediate early genes.
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Project description:Group 2 innate lymphoid cells (ILC2s) play a key role in the initiation and orchestration of early type 2 immune responses. Upon tissue damage, ILC2s are activated by alarmins such as IL-33 and rapidly secrete large amounts of type 2 signature cytokines. ILC2 activation is governed by a network of transcriptional regulators including nuclear factor (NF)-κB family transcription factors. While it is known that activating IL-33 receptor signaling results in downstream NF-κB activation, the underlying molecular mechanisms remain elusive. Here, we found that the NF-κB subunit c-Rel is required to mount effective innate pulmonary type 2 immune responses. IL-33-mediated activation of ILC2s in vitro as well as in vivo was found to induce c-Rel mRNA and protein expression. In addition, we demonstrate that IL-33-mediated activation of ILC2s leads to nuclear translocation of c-Rel in pulmonary ILC2s. Although c-Rel was found to be a critical mediator of innate pulmonary type 2 immune responses, ILC2-intrinsic deficiency of c-Rel did not have an impact on the developmental capacity of ILC2s nor affected homeostatic numbers of lung-resident ILC2s at steady state. Moreover, we demonstrate that ILC2-intrinsic deficiency of c-Rel alters the capacity of ILC2s to upregulate the expression of ICOSL and OX40L, key stimulatory receptors, and the expression of type 2 signature cytokines IL-5, IL-9, IL-13, and granulocyte-macrophage colony-stimulating factor (GM-CSF). Collectively, our data using Rel -/- mice suggest that c-Rel promotes acute ILC2-driven allergic airway inflammation and suggest that c-Rel may contribute to the pathophysiology of ILC2-mediated allergic airway disease. It thereby represents a promising target for the treatment of allergic asthma, and evaluating the effect of established c-Rel inhibitors in this context would be of great clinical interest.
| S-EPMC8635195 | biostudies-literature
Project description:The outcome of cancer and autoimmunity is dictated by the recruitment and effector functions of CD4+ conventional T cells (Tconv cells). The NF-kappaB (NF-κB) family of transcription factors is implicated in different aspects of Tconv cell biology, but the cell-autonomous roles of NF-κB subunits are elusive. Here, we explored the contributions of canonical RelA and c-Rel subunits to Tconv function in health and disease. We found that RelA, rather than c-Rel, shaped the transcriptome of mouse and human Tconv cells at steady-state and was required for Tconv polarization toward the TH17 lineage in vitro. RelA-deficient mice were fully protected against neuro-inflammation in a mouse model of multiple sclerosis (MS), because of defective transition to a pathogenic TH17 gene expression program. In contrast, Tconv-restricted ablation of c-Rel, but not RelA, impaired their function in the microenvironment of transplanted tumors, resulting in enhanced cancer burden. c-Rel in Tconv cells was required for the response to PD-1-blockade therapy, and a c-Rel-dependent gene signature was correlated with better response and prognosis in anti-PD-1-treated patients. Our data demonstrate a division of labor between different subunits of the NF-κB pathway, paving the way for subunit-targeted immunotherapies.
2024-03-28 | GSE239700 | GEO
Project description:The outcome of cancer and autoimmunity is dictated by the recruitment and effector functions of CD4+ conventional T cells (Tconv cells). The NF-kappaB (NF-κB) family of transcription factors is implicated in different aspects of Tconv cell biology, but the cell-autonomous roles of NF-κB subunits are elusive. Here, we explored the contributions of canonical RelA and c-Rel subunits to Tconv function in health and disease. We found that RelA, rather than c-Rel, shaped the transcriptome of mouse and human Tconv cells at steady-state and was required for Tconv polarization toward the TH17 lineage in vitro. RelA-deficient mice were fully protected against neuro-inflammation in a mouse model of multiple sclerosis (MS), because of defective transition to a pathogenic TH17 gene expression program. In contrast, Tconv-restricted ablation of c-Rel, but not RelA, impaired their function in the microenvironment of transplanted tumors, resulting in enhanced cancer burden. c-Rel in Tconv cells was required for the response to PD-1-blockade therapy, and a c-Rel-dependent gene signature was correlated with better response and prognosis in anti-PD-1-treated patients. Our data demonstrate a division of labor between different subunits of the NF-κB pathway, paving the way for subunit-targeted immunotherapies.
2024-03-28 | GSE239698 | GEO
Project description:The outcome of cancer and autoimmunity is dictated by the recruitment and effector functions of CD4+ conventional T cells (Tconv cells). The NF-kappaB (NF-κB) family of transcription factors is implicated in different aspects of Tconv cell biology, but the cell-autonomous roles of NF-κB subunits are elusive. Here, we explored the contributions of canonical RelA and c-Rel subunits to Tconv function in health and disease. We found that RelA, rather than c-Rel, shaped the transcriptome of mouse and human Tconv cells at steady-state and was required for Tconv polarization toward the TH17 lineage in vitro. RelA-deficient mice were fully protected against neuro-inflammation in a mouse model of multiple sclerosis (MS), because of defective transition to a pathogenic TH17 gene expression program. In contrast, Tconv-restricted ablation of c-Rel, but not RelA, impaired their function in the microenvironment of transplanted tumors, resulting in enhanced cancer burden. c-Rel in Tconv cells was required for the response to PD-1-blockade therapy, and a c-Rel-dependent gene signature was correlated with better response and prognosis in anti-PD-1-treated patients. Our data demonstrate a division of labor between different subunits of the NF-κB pathway, paving the way for subunit-targeted immunotherapies.
2024-03-28 | GSE239703 | GEO