Similar Datasets
Project description:Astrocytes differentiation is modulated by the NF-KB pathway
| PRJNA483042 | ENA
Project description:Abstract. Deregulated c-MYC is found in a variety of cancers where it promotes proliferation as well as apoptosis. In many hematological malignancies enhanced NF-kB exerts prosurvival functions. Here we investigated the role of NF-kB in mouse and human c-MYC-transformed lymphomas. The NF-kB-pathway is extinguished in murine lymphoma cells and extrinsic stimuli typically inducing NF-kB activity fail to activate this pathway. Genetic activation of the NF-kB pathway induces apoptosis in these cells, while inhibition of NF-kB by an IkBa superrepressor provides a selective advantage in vivo. Furthermore, in human Burkitt´s lymphoma cells we find that NF-kB activation induces apoptosis. NF-kB upregulates Fas and predisposes to Fas-induced cell death, which is caspase 8 mediated and can be prevented by CFLAR overexpression. We conclude that c-MYC overexpression sensitizes cells to NF-kB-induced apoptosis and persistent inacvtivity of NF-kB signaling is a prerequisite for MYC-mediated tumorigenesis. We could also show that low immunogenicity and Fas insensitivity of MYC driven lymphoma cells is reversed by activation of NF-kB. Our observations provide a molecular explanation for the described absence of the NF-kB signaling in Burkitt´s lymphoma and question the applicability of NF-kB inhibitors as candidates for treatment of this cancer.
2009-07-22 | GSE17129 | GEO
Project description:Brain inflammation, a common feature in neurodegenerative diseases, is a complex series of events, which can be detrimental and even lead to neuronal death. Nonetheless, several studies suggest that inflammatory signals are also positively influencing neural cell proliferation, survival, migration and differentiation. Recently, correlative studies suggested that astrocytes are able to dedifferentiate upon injury, and may thereby re-acquire neural stem cells (NSC) potential. However, the mechanism underlying this dedifferentiation process upon injury remains unclear. In this study, we find that during the early response of reactive gliosis, inflammation induces a conversion of mature astrocytes into neural progenitors. A TNF treatment induces the decrease of specific astrocyte markers, such as GFAP or genes related to glycogen metabolism, while a subset of these cells re-express immaturity markers, such as CD44, Musashi-1 and Oct4. Thus, TNF treatment results in the appearance of cells that exhibit a neural progenitor phenotype and are able to proliferate and differentiate into neurons and/or astrocytes. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we identify a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-kB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-kB pathway. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we identify a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-kB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-kB pathway.
2015-09-16 | GSE73022 | GEO
Project description:Brain inflammation, a common feature in neurodegenerative diseases, is a complex series of events, which can be detrimental and even lead to neuronal death. Nonetheless, several studies suggest that inflammatory signals are also positively influencing neural cell proliferation, survival, migration and differentiation. Recently, correlative studies suggested that astrocytes are able to dedifferentiate upon injury, and may thereby re-acquire neural stem cells (NSC) potential. However, the mechanism underlying this dedifferentiation process upon injury remains unclear. In this study, we find that during the early response of reactive gliosis, inflammation induces a conversion of mature astrocytes into neural progenitors. A TNF treatment induces the decrease of specific astrocyte markers, such as GFAP or genes related to glycogen metabolism, while a subset of these cells re-express immaturity markers, such as CD44, Musashi-1 and Oct4. Thus, TNF treatment results in the appearance of cells that exhibit a neural progenitor phenotype and are able to proliferate and differentiate into neurons and/or astrocytes. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we identify a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-kB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-kB pathway. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we identify a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-kB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-kB pathway. Cultures of primary mouse astrocytes were treated with TNF (50 ng/mL) for 24 hours. Cells were collected and immediately homogenized in cooled down RNA NOW reagent (OZYME). Total RNA was extracted according to RNA NOW manufacturer's recommendations with -20°C overnight incubation for small RNA precipitation. Total RNA integrity and purity were assessed using the Agilent 2100 Bioanalyzer and RNA 6000 Nano LabChip kits (Agilent Technologies). Only good-quality RNA (no contamination or degradation, RIN > 9) was used and further processed. Total RNA samples were reverse-transcribed to double-stranded cDNA using specific primers, which reduce the priming of rRNA. cRNA was generated by in vitro transcription and reverse transcribed into a sense single-stranded cDNA. The cDNA was fragmented, labeled, and hybridized onto Affymetrix GeneChip Mouse Gene 1.0 ST Arrays according to the Ambion Whole Transcript Expression kit for Affymetrix GeneChip Whole Transcript Expression Array Protocol (P/N 4425209 Rev.B 05/2009) and GeneChip WT Terminal Labeling and Hybridization User Manual for use with the Ambion Whole Transcript Expression kit (P/N 702808 Rev.6). Microarrays were then washed, stained, and scanned according to the manufacturer's instructions. The samples cover combinations of 7 time points (0H, 6H, 24H, 48H, 72H, 1W, 2W) and two conditions (TNF and control), with multiple replicates per condition and time point.
2015-09-16 | E-GEOD-73022 | biostudies-arrayexpress
Project description:Astrocytes are taking the center stage in neurotrauma and neurological disease as they appear to play a dominant role in the inflammatory processes associated with these conditions. Previously, we reported that inhibiting nuclear factor kappa B (NF-kB) activation in astrocytes, by using a transgenic mouse model (GFAP-IκBα-dn mice), results in improved functional recovery following spinal cord injury (SCI), with increased white matter preservation and axonal sparing. In the present study we sought to determine whether this improvement, due to inhibiting NF-k-B activation in astrocytes, could be the result of enhanced oligogenesis in our GFAP-IκBα-dn mice. To gain insight into the underlying molecular mechanisms, we performed microarray analysis in naïve and 3 days, 3 and 6 weeks following SCI in GFAP-IκBα-dn and wild type (WT) littermate mice. Surprisingly, we found the largest number of genes differentially regulated between GFAP-IκBα-dn and WT mice 6 weeks post-injury. Interestingly, the data suggested that inhibiting astroglial NF-kB alters the inflammatory environment to support oligogenesis. Furthermore, confirmation of microarray data with qPCR and western blotting analysis and using BrdU labeling along with cell specific immunohistochemistry, confocal microscopy and quantitative cell counts, we demonstrate a significant increase in oligogenesis in GFAP-IκBα-dn following SCI. These studies suggest that therapeutic strategies targeting NF-kB activation in the CNS following SCI may promote oligogenesis and remyelination. Wild type (WT) mice - time points naïve, 3 days, 3 weeks, 6 weeks. Transgenic mice (TG) - time points naïve, 3 days, 3 weeks, 6 weeks.
2013-09-01 | E-GEOD-46695 | biostudies-arrayexpress
Project description:Abstract. Deregulated c-MYC is found in a variety of cancers where it promotes proliferation as well as apoptosis. In many hematological malignancies enhanced NF-kB exerts prosurvival functions. Here we investigated the role of NF-kB in mouse and human c-MYC-transformed lymphomas. The NF-kB-pathway is extinguished in murine lymphoma cells and extrinsic stimuli typically inducing NF-kB activity fail to activate this pathway. Genetic activation of the NF-kB pathway induces apoptosis in these cells, while inhibition of NF-kB by an IkBa superrepressor provides a selective advantage in vivo. Furthermore, in human Burkitt´s lymphoma cells we find that NF-kB activation induces apoptosis. NF-kB upregulates Fas and predisposes to Fas-induced cell death, which is caspase 8 mediated and can be prevented by CFLAR overexpression. We conclude that c-MYC overexpression sensitizes cells to NF-kB-induced apoptosis and persistent inacvtivity of NF-kB signaling is a prerequisite for MYC-mediated tumorigenesis. We could also show that low immunogenicity and Fas insensitivity of MYC driven lymphoma cells is reversed by activation of NF-kB. Our observations provide a molecular explanation for the described absence of the NF-kB signaling in Burkitt´s lymphoma and question the applicability of NF-kB inhibitors as candidates for treatment of this cancer. Experiment Overall Design: Ramos cells were transfected in triplicates with pRTS-GFP (A+,C+,D+) or pRTS-CA-IKK2 (E+,F+,H+), selected with hygromycin and transgene expression was induced with doxycycline (0,5mg/ml) for 48hrs. RNA was isolated with RNeasy mini kit (Qiagen, Venlo, Netherlands) and Gene expression profiling (GEP) was performed using Affymetrix Human Genome U133 Plus 2.0 Array (Affymetrix, Santa Clara, CA, USA). 2 µg of total RNA were labeled using the GeneChip® One-Cycle Target Labeling assay kit (Affymetrix). After hybridization arrays were stained and washed in a FS 450 Fluidics station (Affymetrix) before imaging on an Affymetrix GeneChip (3000) scanner. Raw data were generated using the GCOS 1.4 software (Affymetrix). Probe level data were obtained using the Robust Multichip Average (RMA) normalization algorithm and CEL files were loaded into Genesifter (GeneSifter.Net, VizX Laboratories, Seattle, WA, USA). Genes were identified as differentially expressed among the two classes if a two-sample T-test revealed a nominal significance level of 0.05 and the ratio between the two classes was at least 2 fold. Calculation of false discovery rate was done according to the method of Benjamini and Hochberg. Biological significance was determined using Gene Ontolgy reports.
2009-08-07 | E-GEOD-17129 | biostudies-arrayexpress
Project description:Chronic NF-kB activation in inflammation and cancer has long been linked to persistent activation of NF-kB–responsive gene promoters. However, NF-kB factors also massively bind to gene bodies. Here, we demonstrate that recruitment of the NF-kB factor RELA to intragenic regions regulates alternative splicing upon NF-kB activation by the viral oncogene Tax of HTLV-1. Integrative analyses of RNA splicing and chromatin occupancy, combined with chromatin tethering assays, demonstrate that DNA-bound RELA interacts with and recruits the splicing regulator DDX17, in an NF-kB activation–dependent manner. This leads to alternative splicing of target exons due to the RNA helicase activity of DDX17. Similar results were obtained upon Tax-independent NF-kB activation, indicating that Tax likely exacerbates a physiological process where RELA provides splice target specificity. Collectively, our results demonstrate a physical and direct involvement of NF-kB in alternative splicing regulation, which significantly revisits our knowledge of HTLV-1 pathogenesis and other NF-kB–related diseases.
2020-05-12 | GSE123752 | GEO
Project description:Astrocytes are taking the center stage in neurotrauma and neurological disease as they appear to play a dominant role in the inflammatory processes associated with these conditions. Previously, we reported that inhibiting nuclear factor kappa B (NF-kB) activation in astrocytes, by using a transgenic mouse model (GFAP-IκBα-dn mice), results in improved functional recovery following spinal cord injury (SCI), with increased white matter preservation and axonal sparing. In the present study we sought to determine whether this improvement, due to inhibiting NF-k-B activation in astrocytes, could be the result of enhanced oligogenesis in our GFAP-IκBα-dn mice. To gain insight into the underlying molecular mechanisms, we performed microarray analysis in naïve and 3 days, 3 and 6 weeks following SCI in GFAP-IκBα-dn and wild type (WT) littermate mice. Surprisingly, we found the largest number of genes differentially regulated between GFAP-IκBα-dn and WT mice 6 weeks post-injury. Interestingly, the data suggested that inhibiting astroglial NF-kB alters the inflammatory environment to support oligogenesis. Furthermore, confirmation of microarray data with qPCR and western blotting analysis and using BrdU labeling along with cell specific immunohistochemistry, confocal microscopy and quantitative cell counts, we demonstrate a significant increase in oligogenesis in GFAP-IκBα-dn following SCI. These studies suggest that therapeutic strategies targeting NF-kB activation in the CNS following SCI may promote oligogenesis and remyelination.
2013-09-01 | GSE46695 | GEO
Project description:The nuclear factor kB (NF-kB) subunits RelA, RelB, c-Rel, p50 and p52 are each critical for B-cell development and function. To systematically characterize their responses to canonical and non-canonical NF-kB pathways activity, we performed ChIP-seq analysis in lymphoblastoid B-cells. We found a surprisingly complex NF-kB binding landscape, which did not readily reflect the two NF-kB pathway paradigm. Instead, ten subunit binding patterns were observed at promoters and eleven at enhancers. Surprisingly, nearly one-third of NF-kB binding sites lacked kB motifs. De novo motif finding uncovered distinct modes of NF-kB recruitment at these sites. The oncogenic forkhead box protein FOXM1 and NF-kB co-occupied many kB sites despite the absence of a FOXM1 DNA motif. FoxM1 knockdown decreased expression of key NF-kB targets and caused apoptosis. Our study highlights opportunities for selective therapeutic NF-kB blockade. ChIP-seq was used to define the genomic landscape of NF-kB DNA binding in lymphoblastoid cells.
2014-08-29 | E-GEOD-55105 | biostudies-arrayexpress