NF-κB c-Rel Is Dispensable for the Development but Is Required for the Cytotoxic Function of NK Cells.
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ABSTRACT:
SUBMITTER: Vicioso Y
PROVIDER: S-EPMC8116710 | 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.
| S-EPMC8376415 | 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.
| S-EPMC3314915 | biostudies-literature
Project description:The Rel/NF-κB transcription factor family has myriad roles in immunity, development, and differentiation in animals, and was considered a key innovation for animal multicellularity. Rel homology domain-containing proteins were previously hypothesized to have originated in a last common ancestor of animals and some of their closest unicellular relatives. However, key taxa were missing from previous analyses, necessitating a systematic investigation into the distribution and evolution of these proteins. Here, we address this knowledge gap by surveying taxonomically broad data from eukaryotes, with a special emphasis on lineages closely related to animals. We report an earlier origin for Rel/NF-κB proteins than previously described, in the last common ancestor of animals and fungi, and show that even in the sister group to fungi, these proteins contain elements that in animals are necessary for the subcellular regulation of Rel/NF-κB.
| S-EPMC8763368 | biostudies-literature
Project description:The immune system plays a major role in the protection against cancer. Identifying and characterizing the pathways mediating this immune surveillance are thus critical for understanding how cancer cells are recognized and eliminated. Aneuploidy is a hallmark of cancer, and we previously found that untransformed cells that had undergone senescence due to highly abnormal karyotypes are eliminated by natural killer (NK) cells in vitro. However, the mechanisms underlying this process remained elusive. Here, using an in vitro NK cell killing system, we show that non-cell-autonomous mechanisms in aneuploid cells predominantly mediate their clearance by NK cells. Our data indicate that in untransformed aneuploid cells, NF-κB signaling upregulation is central to elicit this immune response. Inactivating NF-κB abolishes NK cell-mediated clearance of untransformed aneuploid cells. In cancer cell lines, NF-κB upregulation also correlates with the degree of aneuploidy. However, such upregulation in cancer cells is not sufficient to trigger NK cell-mediated clearance, suggesting that additional mechanisms might be at play during cancer evolution to counteract NF-κB-mediated immunogenicity.
| S-EPMC8339690 | biostudies-literature
Project description:Cigarette smoke (CS), a major risk factor for developing lung cancer, is known to activate transcriptional activator nuclear factor kappa B (NF-κB). However, the underlying mechanism of this activation remains unclear because of conflicting reports. As NF-κB has a pivotal role in the generation and maintenance of malignancies, efforts were targeted towards understanding its activation mechanism using both ex vivo and in vivo studies. The results show that CS-induced NF-κB activation mechanism is different from that of other pro-inflammatory signals such as lipopolysaccharide (LPS). The NF-κB dimer that translocates to the nucleus upon stimulation with CS is predominantly composed of c-Rel/p50 and this translocation involves degradation of I-κBɛ and not I-κBα. This degradation of I-κBɛ depends on IKKβ activity, which preferentially targets I-κBɛ. Consistently, CS-activated form of IKKβ was found to be different from that involved in LPS activation as neither Ser177 nor Ser181 of IKKβ is crucial for CS-induced NF-κB activation. Thus, unlike other pro-inflammatory stimulations where p65 and I-κBα have a central role, the predominantly active signaling cascade in CS-induced NF-κB activation in the lung epithelial cells comprises of IKKβ-I-κBɛ-c-Rel/p50. Thus, this study uncovers a new axis of NF-κB activation wherein I-κBɛ and c-Rel have the central role.
| S-EPMC3412642 | biostudies-literature
Project description:Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest malignancies with an overall life expectancy of 6 months despite current therapies. NF-κB signalling has been shown to be critical for this profound cell-autonomous resistance against chemotherapeutic drugs and death receptor-induced apoptosis, but little is known about the role of the c-Rel subunit in solid cancer and PDAC apoptosis control. In the present study, by analysis of genome-wide patterns of c-Rel-dependent gene expression, we were able to establish c-Rel as a critical regulator of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in PDAC. TRAIL-resistant cells exhibited a strong TRAIL-inducible NF-κB activity, whereas TRAIL-sensitive cells displayed only a small increase in NF-κB-binding activity. Transfection with siRNA against c-Rel sensitized the TRAIL-resistant cells in a manner comparable to siRNA targeting the p65/RelA subunit. Gel-shift analysis revealed that c-Rel is part of the TRAIL-inducible NF-κB complex in PDAC. Array analysis identified NFATc2 as a c-Rel target gene among the 12 strongest TRAIL-inducible genes in apoptosis-resistant cells. In line, siRNA targeting c-Rel strongly reduced TRAIL-induced NFATc2 activity in TRAIL-resistant PDAC cells. Furthermore, siRNA targeting NFATc2 sensitized these PDAC cells against TRAIL-induced apoptosis. Finally, TRAIL-induced expression of COX-2 was diminished through siRNA targeting c-Rel or NFATc2 and pharmacologic inhibition of COX-2 with celecoxib or siRNA targeting COX-2, enhanced TRAIL apoptosis. In conclusion, we were able to delineate a novel c-Rel-, NFATc2- and COX-2-dependent antiapoptotic signalling pathway in PDAC with broad clinical implications for pharmaceutical intervention strategies.
| S-EPMC4237244 | biostudies-other
Project description:The integrity of the corneal epithelium is essential for the maintenance of the physiological function of the cornea. Studies have found that inflammation greatly delays corneal wound healing. NF-κB c-Rel is preferentially expressed by immune cells and promotes the expression of inflammatory cytokines. In the current study, we sought to investigate whether c-Rel could be used as a potential therapeutic target for treating a corneal injury. Our studies reveal that expressions of c-Rel and its inflammatory targets are significantly increased in the cornea of mice with corneal injury. In addition, we find that c-Rel-deficient mice exhibit accelerated corneal wound healing and reduced expression of inflammatory cytokines. Further studies show that topical treatment on the corneal surface using nano-polymers or exosomes loaded with c-Rel-specific siRNA (siRel) can effectively accelerate regular and diabetic corneal wound healing. More importantly, we find that exosomes, as carriers of siRel, showed better efficacy than nano-polymers in treating corneal injury. We further demonstrate that exosomes secreted by mesenchymal stem cells can efficiently transfer siRNA into macrophages and dendritic cells but not T cells. Taken together, these results indicate that blocking c-Rel may represent an attracting strategy for the treatment of both regular and diabetic corneal injury.
| S-EPMC9881367 | biostudies-literature
Project description:BackgroundPhosphatidylinositol phosphates (PIPs) are low-abundance phospholipids that participate in a range of cellular processes, including cell migration and membrane traffic. PIP levels and subcellular distribution are regulated by a series of lipid kinases and phosphatases. In skeletal muscle, PIPs and their enzymatic regulators serve critically important functions exemplified by mutations of the PIP phosphatase MTM1 in myotubular myopathy (MTM), a severe muscle disease characterized by impaired muscle structure and abnormal excitation-contraction coupling. FIG4 functions as a PIP phosphatase that participates in both the synthesis and breakdown of phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). Mutation of FIG4 results in a severe neurodegenerative disorder in mice and a progressive peripheral polyneuropathy in humans. The effect of FIG4 mutation on skeletal muscle has yet to be examined.MethodsHerein we characterize the impact of FIG4 on skeletal muscle development and function using the spontaneously occurring mouse mutant pale tremor (plt), a mouse line with a loss of function mutation in Fig4.ResultsIn plt mice, we characterized abnormalities in skeletal muscle, including reduced muscle size and specific force generation. We also uncovered ultrastructural abnormalities and increased programmed cell death. Conversely, we detected no structural or functional abnormalities to suggest impairment of excitation-contraction coupling, a process previously shown to be influenced by PI(3,5)P2 levels. Conditional rescue of Fig4 mutation in neurons prevented overt muscle weakness and the development of obvious muscle abnormalities, suggesting that the changes observed in the plt mice were primarily related to denervation of skeletal muscle. On the basis of the ability of reduced FIG4 levels to rescue aspects of Mtmr2-dependent neuropathy, we evaluated the effect of Fig4 haploinsufficiency on the myopathy of Mtm1-knockout mice. Male mice with a compound Fig4+/-/Mtm1-/Y genotype displayed no improvements in muscle histology, muscle size or overall survival, indicating that FIG4 reduction does not ameliorate the Mtm1-knockout phenotype.ConclusionsOverall, these data indicate that loss of Fig4 impairs skeletal muscle function but does not significantly affect its structural development.
| S-EPMC3844516 | biostudies-literature
Project description:BackgroundNK cell is one of innate immune cells and can protect the body from cancer-initiating cells. It has been reported that GPR116 receptor is involved in inflammation and tumors. However, the effect of GPR116 receptor on the NK cells remains largely unclear.ResultsWe discovered that GPR116-/- mice could efficiently eliminate pancreatic cancer through enhancing the proportion and function of NK cells in tumor. Moreover, the expression of GPR116 receptor was decreased upon the activation of the NK cells. Besides, GPR116-/- NK cells showed higher cytotoxicity and antitumor activity in vitro and in vivo by producing more GzmB and IFNγ than wild-type (WT) NK cells. Mechanistically, GPR116 receptor regulated the function of NK cells via Gαq/HIF1α/NF-κB signaling pathway. Furthermore, downregulation of GPR116 receptor promoted the antitumor activity of NKG2D-CAR-NK92 cells against pancreatic cancer both in vitro and in vivo.ConclusionsOur data indicated that GPR116 receptor had a negatively effect on NK cell function and downregulation of GPR116 receptor in NKG2D-CAR-NK92 cells could enhance the antitumor activity, which provides a new idea to enhance the antitumor efficiency of CAR NK cell therapy.
| S-EPMC9999509 | biostudies-literature
Project description:PurposeThe purpose of this study was to determine the role of nuclear factor kappa B (NF-κB) c-Rel during acute corneal transplant rejection and whether targeting c-Rel can reduce corneal transplant rejection.MethodsAllogeneic corneal transplantation was performed in wild-type and c-Rel-deficient mice. Corneal graft survival rate, opacity, neovascularization, and edema were evaluated by slit-lamp microscopy. Adeno-associated virus 6 (AAV6) expressing c-Rel-specific small hairpin RNA (AAV6-shRel) and the small-molecule compound pentoxifylline (PTXF) were used to reduce c-Rel expression. Enzyme-linked immunosorbent assay was used to determine the expression of inflammatory cytokines. c-Rel expression was determined by quantitative RT-PCR and western blot. The effect of c-Rel inhibition on corneal transplant rejection was examined using a mouse model of acute allogeneic corneal transplantation. Tear production and corneal sensitivity were measured to determine the potential toxicity of AAV6-shRel and PTXF.ResultsThe expression of c-Rel and its inflammatory targets was increased in both mice and patients with corneal transplant rejection. Loss of c-Rel reduced corneal transplant rejection in mouse. Both AAV6-shRel and PTXF were able to downregulate the expression of c-Rel and its inflammatory targets in vitro. Treatment with AAV6-shRel or PTXF reduced corneal transplant rejection in mouse and downregulated the expression of inflammatory cytokines in peripheral blood mononuclear cells from patients with corneal transplant rejection. Treatment with AAV6-shRel or PTXF displayed no side effects on tear production or corneal sensitivity.ConclusionsIncreased expression of c-Rel is a risk factor for acute corneal transplant rejection, and targeting c-Rel can efficiently reduce corneal transplant rejection.
| S-EPMC10653260 | biostudies-literature