Project description:Inducible nucleosome remodeling at hundreds of latent enhancers and several promoters helps shape the transcriptional response to Toll-like receptor 4 (TLR4) signaling in macrophages. However, the identities of the transcription factors that promote TLR-induced remodeling have remained elusive. An analysis strategy that enriched ATAC-seq profiles for genomic regions most likely to undergo remodeling uncovered a unique relationship between NF-kB and TLR4-induced remodeling events. A critical functional role for NF-kB in remodeling was then revealed by CRISPR-Cas9 mutagenesis of NF-kB genes and binding motifs. This critical role is broad and possibly universal during the TLR4 primary response. Remodeling selectivity at defined regions is often conferred by collaboration between NF-kB and other inducible factors, including IRF3 and MAP kinase-induced factors. Thus, NF-kB is unique among TLR4-induced transcription factors in its broad contribution to inducible nucleosome remodeling, alongside its well-established ability to activate poised enhancers and promoters assembled into open chromatin.
Project description:Chronic inflammation and gut microbiota dysbiosis are risk factors for colorectal cancer. In clinical practice, inflammatory bowel disease (IBD) patients have a greatly increased risk of developing colitis associated colorectal cancer (CAC). However, the basis underlying the initiation of CAC remains to be explored. Systematic filtration through existing genome-wide association study (GWAS) and conditional deletion of Zfp90 in CAC mice model indicated that Zfp90 was a putative oncogene in CAC development. Strikingly, depletion of gut microbiota eliminated the tumorigenic effect of Zfp90 in CAC mice model. Moreover, fecal microbiota transplantation demonstrated Zfp90 promoted CAC depending on gut microbiota. Combining 16s rDNA sequencing in feces specimens from CAC mice model, we speculated that Prevotella copri-defined microbiota might mediate the oncogenic role of Zfp90 in the development of CAC. Mechanistic studies revealed Zfp90 accelerated CAC development through Tlr4-Pi3k-Akt-Nf-κb pathway. Our findings elucidated the crucial role of Zfp90-microbiota-Nf-κb axis in creating a tumor-promoting environment and suggested therapeutic targets for CAC prevention and treatment.
Project description:Nf-kB activity is associated with the key pathological features of chronic respiratory diseases including epithelial remodelling, excess mucous production, and submucosal gland hyperplasia. However, the role of Nf-kB activity in airway epithelial differentiation remains controversial. In the present study we demonstrate that Nf-kB adaptor protein Myd88 deficiency promotes increased airway submucosal gland abundance and abnormal epithelial differentiation in proximal adult airways. Abnormal airway differentiation was not developmentally determined, became exacerbated following acute lung injury, and did not involve altered epithelial proliferation or apoptosis. Instead, we demonstrate that tracheal Myd88 deficiency promotes upregulation of a unique gene expression profile that includes activation of alternate, Myd88-independent Nf-kB signalling. Finally, we show that these effects are not intrinsically maintained in vitro using an air-liquid interface epithelial culture. This finding indicates that Myd88 deficiency promotes adult airway remodelling by regulating non-epithelial, non-cell autonomous Nf-kB activity. 20 microarray samples of whole trachea RNA in total: 5 samples wildtype control tissue 5 samples Myd88 KO control tissue 5 samples wildtype 3 day polidocanol injury tissue 5 samples Myd88 KO 3 day polidocanol injury tissue
Project description:Nf-kB activity is associated with the key pathological features of chronic respiratory diseases including epithelial remodelling, excess mucous production, and submucosal gland hyperplasia. However, the role of Nf-kB activity in airway epithelial differentiation remains controversial. In the present study we demonstrate that Nf-kB adaptor protein Myd88 deficiency promotes increased airway submucosal gland abundance and abnormal epithelial differentiation in proximal adult airways. Abnormal airway differentiation was not developmentally determined, became exacerbated following acute lung injury, and did not involve altered epithelial proliferation or apoptosis. Instead, we demonstrate that tracheal Myd88 deficiency promotes upregulation of a unique gene expression profile that includes activation of alternate, Myd88-independent Nf-kB signalling. Finally, we show that these effects are not intrinsically maintained in vitro using an air-liquid interface epithelial culture. This finding indicates that Myd88 deficiency promotes adult airway remodelling by regulating non-epithelial, non-cell autonomous Nf-kB activity.
Project description:Abstract. Background: The cause of ulcerative colitis (UC) is not yet fully understood. Previous research has pointed towards a potential role for mutations in NOD2 in promoting the onset and progression of inflammatory bowel disease (IBD) by altering the microbiota of the gut. However, the relationship between toll-like receptor 4 (TLR4) and gut microbiota in IBD is not well understood. To shed light on this, the interaction between TLR4 and gut microbiota was studied using a mouse model of IBD. Methods: To examine the function of TLR4 signaling in intestinal injury repair, researchers developed Dextran Sulfate Sodium Salt (DSS)-induced colitis and injury models in both wild-type (WT) mice and TLR4 knockout (TLR4-KO) mice. To assess changes in the gut microbiota, 16S rRNA sequencing was conducted on fecal samples from both the TLR4-KO and WT enteritis mouse models. Results: The data obtained depicted a protective function of TLR4 against DSS-induced colitis. The gut microbiota composition was found to vary considerably between the WT and TLR4-KO mice groups as indicated by β-diversity analysis and operational taxonomic units (OTUs) cluster. Statistical analysis of microbial multivariate variables depicted an elevated abundance of Escherichia coli/Shigella, Gammaproteobacteria, Tenerlcutes, Deferribacteres, Enterobacteria, Rikenellaceae, and Proteobacteria in the gut microbiota of TLR4-KO mice, whereas there was a considerable reduction in Bacteroidetes at five different levels of the phylogenetic hierarchy including phylum, class, order, family, and genus in comparison with the WT control. Conclusion: TLR4 may protect intestinal epithelial cells from damage in response to DSS-induced injury by controlling the microbiota in the gut.
Project description:Dysfunctional NF-kB signaling is critically involved in Inflammatory bowel disease (IBD). We investigated the mechanism by which RIPK1 and TRADD, two key mediators of NF-kB signaling, in mediating intestinal pathology using TAK1 IEC deficient model. We show that phosphorylation of TRADD by TAK1 modulates RIPK1-dependent apoptosis. TRADD and RIPK1 act cooperatively to mediate cell death mediated by TNF and TLR signaling. We demonstrate the pathological evolution from RIPK1-dependent ileitis to RIPK1- and TRADD-co-dependent colitis in TAK1 IEC deficient condition. Combined RIPK1 inhibition and TRADD knockout completely protect against intestinal pathology and lethality in TAK1 IEC KO mice. Furthermore, we identify distinctive microbiota dysbiosis biomarkers for RIPK1-dependent ileitis and TRADD-dependent colitis. These findings reveal the cooperation between RIPK1 and TRADD in mediating cell death and inflammation in IBD with NF-kB deficiency and suggest the possibility of combined RIPK1 kinase inhibition and TRADD knockout as a new therapeutic strategy for IBD.
Project description:Dysfunctional NF-kB signaling is critically involved in Inflammatory bowel disease (IBD). We investigated the mechanism by which RIPK1 and TRADD, two key mediators of NF-kB signaling, in mediating intestinal pathology using TAK1 IEC deficient model. We show that phosphorylation of TRADD by TAK1 modulates RIPK1-dependent apoptosis. TRADD and RIPK1 act cooperatively to mediate cell death mediated by TNF and TLR signaling. We demonstrate the pathological evolution from RIPK1-dependent ileitis to RIPK1- and TRADD-co-dependent colitis in TAK1 IEC deficient condition. Combined RIPK1 inhibition and TRADD knockout completely protect against intestinal pathology and lethality in TAK1 IEC KO mice. Furthermore, we identify distinctive microbiota dysbiosis biomarkers for RIPK1-dependent ileitis and TRADD-dependent colitis. These findings reveal the cooperation between RIPK1 and TRADD in mediating cell death and inflammation in IBD with NF-kB deficiency and suggest the possibility of combined RIPK1 kinase inhibition and TRADD knockout as a new therapeutic strategy for IBD.
Project description:Dysfunctional NF-kB signaling is critically involved in Inflammatory bowel disease (IBD). We investigated the mechanism by which RIPK1 and TRADD, two key mediators of NF-kB signaling, in mediating intestinal pathology using TAK1 IEC deficient model. We show that phosphorylation of TRADD by TAK1 modulates RIPK1-dependent apoptosis. TRADD and RIPK1 act cooperatively to mediate cell death mediated by TNF and TLR signaling. We demonstrate the pathological evolution from RIPK1-dependent ileitis to RIPK1- and TRADD-co-dependent colitis in TAK1 IEC deficient condition. Combined RIPK1 inhibition and TRADD knockout completely protect against intestinal pathology and lethality in TAK1 IEC KO mice. Furthermore, we identify distinctive microbiota dysbiosis biomarkers for RIPK1-dependent ileitis and TRADD-dependent colitis. These findings reveal the cooperation between RIPK1 and TRADD in mediating cell death and inflammation in IBD with NF-kB deficiency and suggest the possibility of combined RIPK1 kinase inhibition and TRADD knockout as a new therapeutic strategy for IBD.
Project description:In this study, we demonstrated dysregulation of DNA transcription in H3K4me3 histone in circulating neutrophils of HIV-infected subjects. Chromatin immunoprecipitation sequencing (ChIPseq) H3K4me3 histone analysis revealed that the most spectacular abnormalities were observed in the exons, introns and promoter-TSS regions. Bioinformatic analysis of Gene Ontology, including biological processes, molecular function and cellular components, demonstrated that the main changes were related to the genes responsible for cell activation, cytokine production, adhesive molecule expression, histone remodeling via upregulation of methyltransferase process and downregulation of NF-kB transcription factor in canonical pathways. Abnormalities within H3K4me3 implicated LPS-mediated NF-kB canonical activation pathway that was a result of low amounts of kB DNA sites within histone H3K4me3, low NF-kB (p65 RelA) and TLR4 mRNA expression as well as reduced free NF-kB (p65 RelA) accumulation in the nucleus. ‘Panoramic view of the landscape gene’ within histone H3K4me3 led us postulate that impairment within the canonical NF-kB cell activation pathway may be the primary phenomenon responsible for neutrophil dysfunction observed in HIV-infected individuals
Project description:Among the diseases caused by Toll-like receptor 4 (TLR4) abnormal activation by bacterial endotoxin, sepsis is the most dangerous one. The reprogramming of macrophages plays a crucial role in orchestrating the pathogenesis of sepsis. However, the precise mechanism underlying TLR4 activation in macrophages remained incompletely understood. Our studies revealed that upon lipopolysaccharide (LPS) stimulation, CREB-binding protein (CBP) was recruited to the TLR4 signalosome complex and resulted in pronounced acetylation in the TIR domains of TLR4, Myeloid differentiation factor 88 (MyD88) and MyD88 adapter-like (MAL), which significantly enhanced the activation of the NF-κB signaling pathway and polarization of M1 macrophages. In sepsis patients, significantly elevated TLR4-TIR acetylation was detected in CD16+ monocytes combined with elevated expression of M1 macrophage markers and production of pro-inflammatory cytokines. In contrast, histone deacetylase 1 (HDAC1) served as a key deacetylase in the deacetylation of the TIR domain complex. The inhibition of HDAC1 accelerated sepsis-associated syndromes, while the inhibition of CBP alleviated this process. Overall, our findings highlighted the crucial role of TIR domain complex acetylation in the regulation of inflammatory immune response and suggested that the reversible acetylation of the complex emerged as a promising therapeutic target for M1 macrophages during the progression of sepsis.