Non-canonical NF-kB signaling limits the tolerogenic b-catenin-Raldh2 axis in gut dendritic cells
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ABSTRACT:
ORGANISM(S): Mus musculus (mouse)
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PROVIDER: S-BSST1441 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:Dendritic cell (DC) dysfunction is known to exacerbate intestinal pathologies, but the mechanisms compromising DC-mediated immune regulation in this context remain unclear. Here, we show that intestinal dendritic cells from a mouse model of experimental colitis exhibit significant levels of non-canonical NF-κB signaling, which activates the RelB:p52 heterodimer. Genetic inactivation of this pathway in DCs alleviates intestinal pathologies in mice suffering from colitis. Deficiency of RelB:p52 diminishes transcription of Axin1, a critical component of the β-catenin destruction complex, reinforcing β-catenin-dependent expression of Raldh2, which imparts tolerogenic DC attributes by promoting retinoic acid synthesis. DC-specific impairment of non-canonical NF-κB signaling leads to increased colonic numbers of Tregs and IgA+ B cells, which promote luminal IgA production and foster eubiosis. Experimentally-introduced β-catenin haploinsufficiency in DCs with deficient non-canonical NF-κB signaling moderates Raldh2 activity, reinstating colitogenic sensitivity in mice. Finally, inflammatory bowel-disease patients also display a deleterious non-canonical NF-κB signaling signature in intestinal DCs. In sum, we establish how non-canonical NF-κB signaling in dendritic cells can subvert retinoic acid synthesis to fuel intestinal inflammation.
| S-SCDT-10_1038-S44318-024-00182-6 | biostudies-other
Project description:The mechanisms that underlie the critical dendritic cell (DC) function in maintainance of peripheral immune tolerance are incompletely understood, although the ?-catenin signaling pathway is critical for this role. The molecular details by which ?-catenin signaling is regulated in DCs are unknown. Mechanical disruption of murine bone marrow-derived DC (BMDC) clusters activates DCs while maintaining their tolerogenic potential and this activation is associated with ?-catenin signaling, providing a useful model with which to explore tolerance-associated ?-catenin signaling in DCs. In this report, we demonstrate novel molecular features of the signaling events that control DC activation in response to mechanical stimulation. Non-canonical ?-catenin signaling is an essential component of this tolerogenic activation and is modulated by adhesion molecules, including integrins. This unique ?-catenin-dependent signaling pathway is constitutively active at low levels, suggesting that mechanical stimulation is not necessarily required for induction of this unique activation program. We additionally find that the immunomodulatory cytokine TGF-? antagonizes ?-catenin in DCs, thereby selectively suppressing signaling associated with tolerogenic DC activation while having no impact on LPS-induced, ?-catenin-independent immunogenic activation. These findings provide new molecular insight into the regulation of a critical signaling pathway for DC function in peripheral immune tolerance.
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Project description:BackgroundLymphotoxin β receptor (LTβR) is a member of tumor necrosis factor receptor (TNFR) superfamily which regulates the immune response. At the cellular level, upon ligand binding, the receptor activates the pro-inflammatory NF-κB and AP-1 pathways. Yet, the intracellular distribution of LTβR, the routes of its endocytosis and their connection to the signaling activation are not characterized. Here, we investigated the contribution of LTβR internalization to its signaling potential.MethodsIntracellular localization of LTβR in unstimulated and stimulated cells was analyzed by confocal microscopy. Endocytosis impairment was achieved through siRNA- or CRISPR/Cas9-mediated depletion, or chemical inhibition of proteins regulating endocytic routes. The activation of LTβR-induced signaling was examined. The levels of effector proteins of the canonical and non-canonical branches of the NF-κB pathway, and the phosphorylation of JNK, Akt, ERK1/2, STAT1 and STAT3 involved in diverse signaling cascades, were measured by Western blotting. A transcriptional response to LTβR stimulation was assessed by qRT-PCR analysis.ResultsWe demonstrated that LTβR was predominantly present on endocytic vesicles and the Golgi apparatus. The ligand-bound pool of the receptor localized to endosomes and was trafficked towards lysosomes for degradation. Depletion of regulators of different endocytic routes (clathrin-mediated, dynamin-dependent or clathrin-independent) resulted in the impairment of LTβR internalization, indicating that this receptor uses multiple entry pathways. Cells deprived of clathrin and dynamins exhibited enhanced activation of canonical NF-κB signaling represented by increased degradation of IκBα inhibitor and elevated expression of LTβR target genes. We also demonstrated that clathrin and dynamin deficiency reduced to some extent LTβR-triggered activation of the non-canonical branch of the NF-κB pathway.ConclusionsOur work shows that the impairment of clathrin- and dynamin-dependent internalization amplifies a cellular response to LTβR stimulation. We postulate that receptor internalization restricts responsiveness of the cell to subthreshold stimuli. Video Abstract.
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Project description:The non-canonical NF-κB pathway is an important arm of NF-κB signaling that predominantly targets activation of the p52/RelB NF-κB complex. This pathway depends on the inducible processing of p100, a molecule functioning as both the precursor of p52 and a RelB-specific inhibitor. A central signaling component of the non-canonical pathway is NF-κB-inducing kinase (NIK), which integrates signals from a subset of TNF receptor family members and activates a downstream kinase, IκB kinase-α (IKKα), for triggering p100 phosphorylation and processing. A unique mechanism of NIK regulation is through its fate control: the basal level of NIK is kept low by a TRAF-cIAP destruction complex and signal-induced non-canonical NF-κB signaling involves NIK stabilization. Tight control of the fate of NIK is important, since deregulated NIK accumulation is associated with lymphoid malignancies.
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2021-10-05 | GSE181493 | GEO
Project description:Lack of effective anti-metastatic drugs creates a major hurdle for metastatic lung cancer therapy. For successful lung cancer treatment, there is a strong need of newer therapeutics with metastasis-inhibitory potential. In the present study, we determined the anti-metastatic and anti-angiogenic potential of a natural plant triterpenoid, Cucurbitacin B (CuB) against non-small cell lung cancer (NSCLC) both in vitro and in vivo. CuB demonstrated a strong anti-migratory and anti-invasive ability against metastatic NSCLC at nanomolar concentrations. CuB also showed significant tumor angiogenesis-inhibitory effects as evidenced by the inhibition of migratory, invasive and tube-forming capacities of human umbilical vein endothelial cells. CuB-mediated inhibition of angiogenesis was validated by the inhibition of pre-existing vasculature in chick embryo chorio-allantoic membrane and matrigel plugs. Similarly, CuB inhibited the migratory behavior of TGF-?1-induced experimental EMT model. The CuB-mediated inhibition of metastasis and angiogenesis was attributable to the downregulation of Wnt/?-catenin signaling axis, validated by siRNA-knockdown of Wnt3 and Wnt3a. The CuB-mediated downregulation of Wnt/?-catenin signaling was also validated using 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis model in vivo. Collectively, our findings suggest that CuB inhibited the metastatic abilities of NSCLC through the inhibition of Wnt/?-catenin signaling axis.
| S-EPMC4764833 | biostudies-other
Project description:The ability of dendritic cells (DC) to initiate immunity and induce antigen-specific tolerance makes DC ideal targets for pharmacological intervention into immune responses. NF-kB factors are a family of transcriptional regulators important for DC development and function. However, the identity of NF-kB target genes that are central to DC biology is largely unknown. In the present study IkBa super repressor (IkBa-SR) and DNA microarray analysis were used to determine the repertoire of NF-kB responsive genes in DC. In DC these genes regulate vital DC functions of antigen uptake and presentation, motility, survival, etc. Taking in account limitations of the genome-wide microarray analysis, generated transcription factor data were confirmed by the independent means of RT-PCR and chromatin immunoprecipitation. Kinetics of NF-kB induction by well-known DC activatory agents TNFa and LPS were further analysed. NF-kB regulated genes can be potentially useful targets for the development of more specific anti-inflammatory agents for clinical applications. Keywords: drug treatment, adenovirus transduction
2012-12-31 | GSE8009 | GEO
Project description:The ability of dendritic cells (DC) to initiate immunity and induce antigen-specific tolerance makes DC ideal targets for pharmacological intervention into immune responses. NF-kB factors are a family of transcriptional regulators important for DC development and function. However, the identity of NF-kB target genes that are central to DC biology is largely unknown. In the present study IkBa super repressor (IkBa-SR) and DNA microarray analysis were used to determine the repertoire of NF-kB responsive genes in DC. In DC these genes regulate vital DC functions of antigen uptake and presentation, motility, survival, etc. Taking in account limitations of the genome-wide microarray analysis, generated transcription factor data were confirmed by the independent means of RT-PCR and chromatin immunoprecipitation. Kinetics of NF-kB induction by well-known DC activatory agents TNFa and LPS were further analysed. NF-kB regulated genes can be potentially useful targets for the development of more specific anti-inflammatory agents for clinical applications. Keywords: drug treatment, adenovirus transduction DC were generated in vitro from bone marrow of CAR transgenic mice as described previously (Hieronymus, T., T. C. Gust, R. D. Kirsch, T. Jorgas, G. Blendinger, M. Goncharenko, K. Supplitt, S. Rose-John, A. M. Muller, and M. Zenke. 2005. Progressive and controlled development of mouse dendritic cells from Flt3+CD11b+ progenitors in vitro. J Immunol 174:2552-2562). Immature DC were transduced with AdIkBa-SR adenovirus, AdOVA control virus, or left untreated. Cells were then stimulated with TNFa, or left unstimulated. Total RNA was amplified, labelled and hybridised to Affymetrix MOE430A arrays. TNFa up- and down-regulated genes, as well as genes regulated by AdOVA control virus, and suppressed by AdIkBa-SR were analysed.
2012-12-31 | E-GEOD-8009 | biostudies-arrayexpress
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