Project description:To determine the underlying mechanisms by which trametinib affected LPS-induced inflammatory response in macrophages, we performed microarrays to define the global gene expression in murine peritoneal macrophages treating with trametinib or vehicle followed by LPS stimulation.
Project description:Sepsis is a potentially life-threatening condition caused by the body's response to a severe infection. However, the pathogenesis of sepsis remains unclear. Here, we found that Suppressor of Fused (Sufu), a classical negative regulator of Hedgehog signaling, is downregulated in patients with sepsis and in murine peritoneal macrophages treated with lipopolysaccharide (LPS). Deletion of Sufu aggravated LPS-induced lung injury and lethality in mice, and augmented LPS induced proinflammatory gene expression in cultured macrophages. By RNA-seq transcriptome profiling, we identified Sufu as a negative regulator of the TLR-triggered inflammatory response.
Project description:Proinflammatory stimuli rapidly and globally remodel chromatin landscape, thereby enabling transcriptional responses. Yet, the mechanisms coupling chromatin regulators to the master regulatory inflammatory transcription factor NF-kB remain poorly understood. We report in human endothelial cells (ECs) that activated NF-kB binds to enhancers, provoking a rapid, global redistribution of BRD4 preferentially at super-enhancers, large enhancer domains highly bound by chromatin regulators. Newly established NF-kB super-enhancers drive nearby canonical inflammatory response genes. In both ECs and macrophages BET bromodomain inhibition prevents super-enhancer formation downstream of NF-kB activation, abrogating proinflammatory transcription. In TNFa-activated endothelium this culminates in functional suppression of leukocyte rolling, adhesion and transmigration. Sustained BET bromodomain inhibitor treatment of LDLr -/- animals suppresses atherogenesis, a disease process rooted in pathological vascular inflammation involving endothelium and macrophages. These data establish BET-bromodomains as key effectors of inflammatory response through their role in the dynamic, global reorganization of super-enhancers during NF-kB activation. Gene expression analysis of human endothelial cells in resting state, treatment with TNFalpha or TNFalpha with the BET bromodomain inhibitor JQ1
Project description:Proinflammatory stimuli rapidly and globally remodel chromatin landscape, thereby enabling transcriptional responses. Yet, the mechanisms coupling chromatin regulators to the master regulatory inflammatory transcription factor NF-kB remain poorly understood. We report in human endothelial cells (ECs) that activated NF-kB binds to enhancers, provoking a rapid, global redistribution of BRD4 preferentially at super-enhancers, large enhancer domains highly bound by chromatin regulators. Newly established NF-kB super-enhancers drive nearby canonical inflammatory response genes. In both ECs and macrophages BET bromodomain inhibition prevents super-enhancer formation downstream of NF-kB activation, abrogating proinflammatory transcription. In TNFa-activated endothelium this culminates in functional suppression of leukocyte rolling, adhesion and transmigration. Sustained BET bromodomain inhibitor treatment of LDLr -/- animals suppresses atherogenesis, a disease process rooted in pathological vascular inflammation involving endothelium and macrophages. These data establish BET-bromodomains as key effectors of inflammatory response through their role in the dynamic, global reorganization of super-enhancers during NF-kB activation. Chem-Seq for the biotinylated small molecule JQ1 in untreated or TNFalpha treated human endothelial cells
Project description:When macrophages are activated by sensing bacterial lipopolysaccharides (LPS), they greatly increase their motility, mRNA synthesis and protein production. Most of the ATP needed for these responses is derived from the uptake and catabolism of glucose, a relatively inefficient ATP source. Although the stimulated cells also increase their uptake of free fatty acids, they store a large fraction as triglycerides (TAG). We report here that both Toll-like receptor 4 (TLR4) and TLR2 agonists stimulate prolonged TAG retention by primary murine and human macrophages. Agonist-induced TAG storage lasted at least 72-96 hrs in vitro and was associated with increases in fatty acid (FA) uptake, FA esterification, and FA incorporation into TAG; FA oxidation decreased. The results of expression and inhibitor studies support a prominent role for increases in long chain acyl CoA synthase 1 (ACSL1) and diacylglycerol acyltransferase-2 (DGAT2) during the sustained response to TLR2/4 activation; decreases in adipose triglyceride lipase (ATGL, Pnpla2) and monoacylglycerol lipase (MgII) may also contribute. Stimulated murine macrophages that retained TAG carried out phagocytosis more effectively and were protected from saturated fatty acid-induced cell death (lipotoxicity). TLR agonist-induced TAG retention in macrophages is thus an active, sustained process that may have important adaptive functions. It may also contribute to the persistence of lipid-laden macrophages in infected tissues, host susceptibility to some microbial pathogens, and the pathogenesis of atherosclerosis. RNA from macrophage loaded with Fatty Acids, stimulated with bacterial lipopolysaccharides (LPS), or both compared to untreated controls (FA, LPS, FA+LPS, untreated). Replicates from 4 independent experiments.
Project description:The responses of macrophages to lipopolysaccharide (LPS) might determine the direction of clinical manifestations of sepsis, which is the immune response against severe infection. Meanwhile, the enhancer of zeste homologue 2 (Ezh2), a histone lysine methyltransferase of epigenetic regulation, might interfere with LPS response. With a single LPS stimulation, Ezh2 null(Ezh2flox/flox; LysM-Crecre/−) macrophages demonstrated lower supernatant TNF-α than Ezh2 control (Ezh2fl/fl; LysM-Cre−/−), perhaps due to an upregulation of Socs3, which is a suppressor of cytokine signaling 3, due to the loss of the Ezh2 gene. In LPS tolerance, Ezh2 null macrophages indicated higher supernatant TNF-α and IL-6 than the control, supporting an impact of the loss of the Ezh2 inhibitory gene. In parallel, Ezh2 null mice demonstrated lower serum TNF-α and IL-6 than the control mice after an LPS injection, indicating a less severe LPS-induced hyper-inflammation in Ezh2 null mice. In conclusion, an absence of Ezh2 in macrophages resulted in less severe LPS-induced inflammation, as indicated by low serum cytokines, with less severe LPS tolerance, as demonstrated by higher cytokine production, partly through the upregulated Socs3.
Project description:In colitis, macrophage functionality is altered compared to normal homeostatic conditions. Loss of IL-10 signaling results in an inappropriate chronic inflammatory response to bacterial stimulation. It remains unknown if inhibition of bromodomain and extra-terminal domain (BET) proteins alters usage of DNA regulatory elements responsible for driving inflammatory gene expression. We determined if the BET inhibitor, (+)-JQ1, could suppress inflammatory activation of macrophages in Il10-/- mice. We performed ATAC-seq and RNA-seq on Il10-/- bone marrow-derived macrophages (BMDMs) cultured in the presence and absence of lipopolysaccharide (LPS) with and without treatment with (+)-JQ1 and evaluated changes in chromatin accessibility and gene expression. Treatment with (+)-JQ1 suppressed LPS-induced changes in chromatin at distal regulatory elements associated with inflammatory genes, particularly in regions that contain motifs for AP-1 and IRF transcription factors.
Project description:In colitis, macrophage functionality is altered compared to normal homeostatic conditions. Loss of IL-10 signaling results in an inappropriate chronic inflammatory response to bacterial stimulation. It remains unknown if inhibition of bromodomain and extra-terminal domain (BET) proteins alters usage of DNA regulatory elements responsible for driving inflammatory gene expression. We determined if the BET inhibitor, (+)-JQ1, could suppress inflammatory activation of macrophages in Il10-/- mice. We performed ATAC-seq and RNA-seq on Il10-/- bone marrow-derived macrophages (BMDMs) cultured in the presence and absence of lipopolysaccharide (LPS) with and without treatment with (+)-JQ1 and evaluated changes in chromatin accessibility and gene expression. Treatment with (+)-JQ1 suppressed LPS-induced changes in chromatin at distal regulatory elements associated with inflammatory genes, particularly in regions that contain motifs for AP-1 and IRF transcription factors.
Project description:Here we are using TMT-based proteomic analysis to characterize changes in the protein content of ribosomal complexes in LPS or poly(I:C) treated vs naive murine macrophages.