Cardiomyocyte TLR4 regulates autophagy through TRAF6-mediated TFEB ubiquitination in sepsis-associated cardiac dysfunction
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PROVIDER: PRJNA770670 | ENA |
REPOSITORIES: ENA
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Project description:Sepsis-associated cardiac dysfunction (SACD) is the predominant cause of death in sepsis patients with undefined mechanism of inflammation-autophagy interaction to date. Herein, time-course analysis of cardiac autophagy was conducted in a mouse model of SCAD. An in vitro model established by Lipopolysaccharide-induced macrophage conditioned media stimulation on cardiomyocytes was further investigated for molecular insights. We show cardiomyocyte Toll-like receptor 4 (cTLR4) serves as a central receptor mediating the crosstalk between cardiomyocyte and macrophage, and activation of cTLR4 intensifies the impairment of autophagic flux in cardiomyocytes. Mechanistically, the activation of cTLR4 inactivates TFEB, which largely depends on the E3 ligase activity of TRAF6. Moreover, computational simulation combined with experimental validation revealed the unique local electrostatic interactions between TRAF6 and TFEB. Collectively, our results highlight a previously undescribed role of cTLR4-TRAF6-TFEB signaling in modulating cardiac injury and identify the TRAF6-binding motif in TFEB as an attractive target for SACD therapy.
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Project description:Toll-like receptors (TLR) activation contributes to premalignant hematologic conditions, such as myelodysplastic syndromes (MDS). TRAF6, a TLR effector with ubiquitin (Ub) ligase activity, is overexpressed in MDS hematopoietic stem/progenitor cells (HSPCs). We found that TRAF6 overexpression in mouse HSPC results in impaired hematopoiesis and bone marrow failure. Using a global Ub screen, we identified hnRNPA1, an RNA-binding protein and auxiliary splicing factor, as a substrate of TRAF6. TRAF6 ubiquitination of hnRNPA1 regulated alternative splicing of Arhgap1, which resulted in activation of the GTP-binding Rho family protein Cdc42 and accounted for hematopoietic defects in TRAF6-expressing HSPCs. These results implicate Ub signaling in coordinating RNA processing by TLR pathways during an immune response and in premalignant hematologic diseases, such as MDS.
2016-12-20 | GSE64542 | GEO
Project description:Excessive generation and accumulation of highly reactive oxidizing molecules causes oxidative stress and oxidative damage to cellular components. Accumulating evidence indicates that autophagy diminishes oxidative damage in cells and maintains redox homeostasis by degrading and recycling intracellular damaged components. However, the molecular mechanisms underlying the activation of oxidative stress-mediated autophagic response remain elusive. Here we show that ubiquitin E3 ligase TNF receptor-associated factor 6 (TRAF6) and the deubiquitinase A20 coordinate to regulate ATG9A ubiquitination and autophagy activation in cells responding to oxidative stress. The reactive oxygen species (ROS)-dependent TRAF6-mediated non-proteolytic, K48/63-linked ubiquitination of ATG9A enhances its association with Beclin 1 and the assembly of class III phosphatidylinositol-3-kinase (PI3KC3/VPS34) UVRAG complex, thereby stimulating autophagy. Notably, depletion of ATG9A or expression of the ATG9A ubiquitination mutants markedly decreases ROS-induced VPS34 activation and autophagy. We further find that lipopolysaccharide (LPS)-induced ROS production also stimulates TRAF6-mediated ATG9A ubiquitination and enhances the assembly of the UVRAG-containing VPS34 complex in an ATG9A-dependent manner. Ablation of ATG9A causes aberrant TLR4 endosomal trafficking and decreased phosphorylation of IRF-3 in LPS-stimulated macrophages. Our findings provide important insight into how K48/K63-linked ubiquitination of ATG9A contributes to the regulation of oxidative stress-induced autophagy.
2022-02-24 | PXD030415 | Pride
Project description:TRAF6 -/- thymi display defects in IR-induced p53 target gene expression and attenuate further enhancement of apoptosis upon IR treatment. TRAF6-mediated K63-linked ubiquitination of p53 at K24
2016-11-04 | GSE69730 | GEO
Project description:TRAF-interacting protein with forkhead-associated domain B (TIFAB) is a haploinsufficient gene in del(5q) Myelodysplastic syndrome (MDS). Hematopoietic-specific deletion of Tifab results in progressive bone marrow (BM) and blood defects, including skewed hematopoietic stem/progenitor cells (HSPC) proportions, altered myeloid differentiation, and progressive cytopenia. A subset of mice transplanted with Tifab knockout (KO) hematopoietic cells develop a bone marrow failure (BMF)-like disease with neutrophil dysplasia and cytopenia. In competitive transplants, Tifab KO HSPC are out-competed by wild-type (WT) cells, suggesting a cell-intrinsic HSPC defect. Gene expression analysis of Tifab KO HSPC identified dysregulation of immune-related signatures, and hypersensitivity to Toll-like receptor 4 (TLR4) stimulation. TIFAB also forms a complex with TRAF6, a mediator of immune signaling, and reduces TRAF6 protein stability by a lysosome-dependent mechanism. In contrast, TIFAB loss increases TRAF6 protein and the dynamic range of TLR4 signaling in HSPC, contributing to ineffective hematopoiesis. Moreover, combined deletion of TIFAB and miR-146a, two genes associated with del(5q) MDS/AML, results in a cooperative increase in TRAF6 expression and hematopoietic dysfunction in vivo. Re-expression of TIFAB in human del(5q) leukemic cells results in attenuated TLR4 signaling and reduced cell viability. These findings underscore the importance of efficient regulation of innate immune/TRAF6 signaling within HSPC by TIFAB, and its cooperation with miR-146a as it relates to the pathogenesis of hematopoietic malignancies, such as del(5q) MDS/AML. We performed an expression analysis on sorted lineage-Sca1+cKit+ (LSK) isolated from bone marrow (BM) of 3 month old mice transplanted with Tifab+/+ (WT) or Tifab-/- (KO) BM cells (n = 3 mice/group). We selected this time point to capture the gene expression profile of Tifab-/- LSK after engraftment but prior to overt hematopoietic failure. Total RNA was extracted, purified, reverse transcribed, labeled, and hybridized onto the GeneChip MoGene 2.0 ST Array (Affymetrix). Comparison comprises mRNA expression profile of Tifab+/+ LSK vs. Tifab-/- LSK.
2015-09-12 | E-GEOD-72936 | biostudies-arrayexpress
Project description:TRAF-interacting protein with forkhead-associated domain B (TIFAB) is a haploinsufficient gene in del(5q) Myelodysplastic syndrome (MDS). Hematopoietic-specific deletion of Tifab results in progressive bone marrow (BM) and blood defects, including skewed hematopoietic stem/progenitor cells (HSPC) proportions, altered myeloid differentiation, and progressive cytopenia. A subset of mice transplanted with Tifab knockout (KO) hematopoietic cells develop a bone marrow failure (BMF)-like disease with neutrophil dysplasia and cytopenia. In competitive transplants, Tifab KO HSPC are out-competed by wild-type (WT) cells, suggesting a cell-intrinsic HSPC defect. Gene expression analysis of Tifab KO HSPC identified dysregulation of immune-related signatures, and hypersensitivity to Toll-like receptor 4 (TLR4) stimulation. TIFAB also forms a complex with TRAF6, a mediator of immune signaling, and reduces TRAF6 protein stability by a lysosome-dependent mechanism. In contrast, TIFAB loss increases TRAF6 protein and the dynamic range of TLR4 signaling in HSPC, contributing to ineffective hematopoiesis. Moreover, combined deletion of TIFAB and miR-146a, two genes associated with del(5q) MDS/AML, results in a cooperative increase in TRAF6 expression and hematopoietic dysfunction in vivo. Re-expression of TIFAB in human del(5q) leukemic cells results in attenuated TLR4 signaling and reduced cell viability. These findings underscore the importance of efficient regulation of innate immune/TRAF6 signaling within HSPC by TIFAB, and its cooperation with miR-146a as it relates to the pathogenesis of hematopoietic malignancies, such as del(5q) MDS/AML.
2015-09-12 | GSE72936 | GEO
Project description:Clonal hematopoiesis of indeterminant potential (CHIP) is an aging-associated condition characterized by the clonal outgrowth of self-renewing cells that acquire specific mutations. One of the most frequent mutations in CHIP targets the methylcytosine dioxygenase TET2, also observed in number of myeloid neoplasms 1,2. Although individuals with CHIP are healthy, they are at an increased risk of developing hematopoietic malignancies. These findings indicate that additional alterations are needed for the transition from a pre-leukemic (CHIP) stage to frank leukemia, although the identity of such molecular events remains poorly characterized. To identify signaling states that cooperate with CHIP mutant cells we used an in vivo RNAi screening approach. One of the most prominent genes identified was the ubiquitin ligase TRAF6. We demonstrate that TRAF6 is repressed in a subset of acute myeloid leukemia (AML) and myeloproliferative neoplasm (MPN) patients. Loss of TRAF6 in pre-leukemic HSPC results in overt AML/MPN and is associated with induction of MYC-dependent leukemic stem cell signatures. TRAF6 represses MYC activity at enhancers due to the ubiquitination of MYC on Lysine (K)148. Ubiquitination of MYC on K148, does not affect protein stability but rather antagonizes acetylation of MYC on the same lysine and suppresses MYC oncogenic activity by preventing its DNA binding. Our results identify a novel tumor suppressor function for TRAF6 and demonstrate a novel mode of regulation of MYC oncogenic activity
2022-01-01 | GSE189172 | GEO
Project description:The model was constructed to describe TLR4 induced NF-κB activation in native bone marrow-derived macrophages. It included processes of ligand (lipopolysaccharide) recognition, formation of dimer receptor complex and further signal transduction through TRAF6/TAK1 complex that leads to the activation of IKKα/β kinase, which in turn enables the NF-κB transcription factor phosphorylation and translocation in the cell nucleus, and induction of IkB and WIP1 (as an example of induced protein that promotes NF-κB dephosphorylation 2) gene transcription. Models were based on the current knowledge of TLR signaling framework, protein interactions within the TLR4 pathway, and up-to-date mathematical models describing Toll receptor activation.
The major important additions were made to TLR4 signaling description:
1) Receptor dimerization process
2) The existence of a basal nuclear NF-κB level (translocation)
3) NF-κB phosphorylation by IKK complex
2019-03-27 | MODEL1809230001 | BioModels
Project description: Not available
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Project description:To investigate the genomic localization of NCoR/HDAC3/PGC1β complex and the enhancer/promoter activity in inflammatory genes, we used NCoR KO or PGC1β KO bone marrow-derived macrophages and Traf6 siRNA knockdown bone marrow-derived macrophages. We then performed chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for H3K27ac, NCoR, HDAC3, PGC1β, ERK1, p65, Fosl2, PU.1 and p300.
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