HDAC3 requirement for the inflammatory gene expression program in macrophages [gene expression]
Ontology highlight
ABSTRACT: Pan-Hdac inhibitors (HDACi) are endowed with a potent anti-inflammatory activity, but the relative role of each of the eleven Hdac proteins sensitive to HDACi to the inflammatory gene expression program is unknown. Using an integrated genomic approach we found that Hdac3-deficient macrophages are unable to activate almost half of the inflammatory gene expression program when stimulated with lipopolysaccharide (LPS). A large part of the activation defect is due to loss of basal and LPS-inducible expression of IFNb, which in basal cells maintains Stat1 protein levels, and after stimulation acts in an autocrine/paracrine manner to promote a secondary wave of Stat1-dependent gene expression. We show that loss of Hdac3-mediated repression of nuclear receptors leads to hyperacetylation of thousands of genomic sites and associated gene derepression. The upregulation of the constitutively expressed prostaglandin endoperoxide synthase, Ptgs1 (Cox-1), has a causative role in the phenotype, since its chemical inhibition reverts the Ifnb activation defect. These data may have relevance for the use of selective Hdac inhibitors as anti-inflammatory agents. Gene expression profiles for bone marrow-derived macrophages from either HDAC3 +/- (wt) or HDAC3 -/- (KO). Cells were left untreated or challenged with lipopolysaccharide (LPS) for 4hrs. Each genotype-treatment combination was performed in triplicate.
Project description:Pan-Hdac inhibitors (HDACi) are endowed with a potent anti-inflammatory activity, but the relative role of each of the eleven Hdac proteins sensitive to HDACi to the inflammatory gene expression program is unknown. Using an integrated genomic approach we found that Hdac3-deficient macrophages are unable to activate almost half of the inflammatory gene expression program when stimulated with lipopolysaccharide (LPS). A large part of the activation defect is due to loss of basal and LPS-inducible expression of IFNb, which in basal cells maintains Stat1 protein levels, and after stimulation acts in an autocrine/paracrine manner to promote a secondary wave of Stat1-dependent gene expression. We show that loss of Hdac3-mediated repression of nuclear receptors leads to hyperacetylation of thousands of genomic sites and associated gene derepression. The upregulation of the constitutively expressed prostaglandin endoperoxide synthase, Ptgs1 (Cox-1), has a causative role in the phenotype, since its chemical inhibition reverts the Ifnb activation defect. These data may have relevance for the use of selective Hdac inhibitors as anti-inflammatory agents. Chromatin immuno-precipitations of H4 histone pan-acetylation followed by multiparallel sequencing performed in murine bone marrow-derive macrophages. Experiments carried out in untreated cells as well as in cells treated for 4hrs with lipopolysaccharide (LPS), for both HDAC3 +/- (wt) and HDAC3 -/- (KO) mice.
Project description:Pan-Hdac inhibitors (HDACi) are endowed with a potent anti-inflammatory activity, but the relative role of each of the eleven Hdac proteins sensitive to HDACi to the inflammatory gene expression program is unknown. Using an integrated genomic approach we found that Hdac3-deficient macrophages are unable to activate almost half of the inflammatory gene expression program when stimulated with lipopolysaccharide (LPS). A large part of the activation defect is due to loss of basal and LPS-inducible expression of IFNb, which in basal cells maintains Stat1 protein levels, and after stimulation acts in an autocrine/paracrine manner to promote a secondary wave of Stat1-dependent gene expression. We show that loss of Hdac3-mediated repression of nuclear receptors leads to hyperacetylation of thousands of genomic sites and associated gene derepression. The upregulation of the constitutively expressed prostaglandin endoperoxide synthase, Ptgs1 (Cox-1), has a causative role in the phenotype, since its chemical inhibition reverts the Ifnb activation defect. These data may have relevance for the use of selective Hdac inhibitors as anti-inflammatory agents.
Project description:Pan-Hdac inhibitors (HDACi) are endowed with a potent anti-inflammatory activity, but the relative role of each of the eleven Hdac proteins sensitive to HDACi to the inflammatory gene expression program is unknown. Using an integrated genomic approach we found that Hdac3-deficient macrophages are unable to activate almost half of the inflammatory gene expression program when stimulated with lipopolysaccharide (LPS). A large part of the activation defect is due to loss of basal and LPS-inducible expression of IFNb, which in basal cells maintains Stat1 protein levels, and after stimulation acts in an autocrine/paracrine manner to promote a secondary wave of Stat1-dependent gene expression. We show that loss of Hdac3-mediated repression of nuclear receptors leads to hyperacetylation of thousands of genomic sites and associated gene derepression. The upregulation of the constitutively expressed prostaglandin endoperoxide synthase, Ptgs1 (Cox-1), has a causative role in the phenotype, since its chemical inhibition reverts the Ifnb activation defect. These data may have relevance for the use of selective Hdac inhibitors as anti-inflammatory agents.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:This SuperSeries is composed of the following subset Series: GSE33162: HDAC3 requirement for the inflammatory gene expression program in macrophages [gene expression] GSE33163: HDAC3 requirement for the inflammatory gene expression program in macrophages [ChIP_Seq] Refer to individual Series
Project description:Since its discovery over three decades ago, signal transducer and activator of transcription 1 (STAT1) has been extensively studied as a central mediator for interferons (IFNs) signaling and antiviral defense. Here, using genetic and biochemical assays, we unveil Thr748 as a conserved IFN-independent phosphorylation switch in Stat1, which restricts IFN signaling and promotes innate inflammatory responses following the recognition of the bacterial-derived toxin lipopolysaccharide (LPS). Genetically-engineered mice expressing phospho-deficient threonine748–to-alanine (T748A) mutant Stat1 are resistant to LPS–induced lethality. Of note, T748A mice exhibited undisturbed IFN signaling, as well as total expression of Stat1. Further, the T748A point-mutation of Stat1 recapitulates the safeguard effect of the genetic ablation of Stat1 following LPS-induced lethality, indicating that the Thr748 phosphorylation contributes inflammatory functionalities of Stat1. Mechanistically, LPS-induced Toll-like receptor 4 endocytosis activates a cell-intrinsic IκB kinase (IKK)–mediated Thr748 phosphorylation of Stat1, which promotes macrophages inflammatory response while restricting the IFN and anti-inflammatory responses. Depletion of macrophages restores the sensitivity of the T748A mice to LPS-induced lethality. Together, our study indicates a phosphorylation-dependent functional dichotomy of Stat1 in innate immune responses: IFN phospho-tyrosine dependent, and inflammatory phospho-threonine dependent. Better understanding of the Thr748 phosphorylation of Stat1 may uncover novel pharmacologically targetable molecules and offer better treatment modalities for sepsis, a disease that claims millions of lives annually.
Project description:The transcription factor Signal Transducer and Activator of Transcription (STAT) 1 is activated by Interferon gamma (IFNγ) but also Lipopolysaccharide (LPS) is the trigger of inflammation. STAT1 together with downstream activated Interferon Regulatory Factors (IRF) create a platform for signal integration between IFNγ and the Toll-Like Receptor (TLR) 4 ligand in immune cells. Little is known about the role of STAT1 and IRFs on potential synergism between LPS- and INFγ-signaling in cells from the vasculature. We investigated whether vascular cells can promote inflammatory signaling by the STAT1-IRFs pathway.
Project description:The transcription factor (TF) interferon regulatory factor 8 (IRF8) controls both developmental and inflammatory stimulus-inducible genes in macrophages, but the mechanisms underlying these two different functions are largely unknown. One possibility is that these different roles are linked to the ability of IRF8 to bind alternative DNA sequences. We found that IRF8 is recruited to distinct sets of DNA consensus sequences before and after lipopolysaccharide (LPS) stimulation. In resting cells, IRF8 was mainly bound to composite sites together with the master regulator of myeloid development PU.1. Basal IRF8M-bM-^@M-^SPU.1 binding maintained the expression of a broad panel of genes essential for macrophage functions (such as microbial recognition and response to purines) and contributed to basal expression of many LPS-inducible genes. After LPS stimulation, increased expression of IRF8, other IRFs, and AP-1 family TFs enabled IRF8 binding to thousands of additional regions containing low-affinity multimerized IRF sites and composite IRFM-bM-^@M-^SAP-1 sites, which were not premarked by PU.1 and did not contribute to the basal IRF8 cistrome. While constitutively expressed IRF8-dependent genes contained only sites mediating basal IRF8/PU.1 recruitment, inducible IRF8-dependent genes contained variable combinations of constitutive and inducible sites. Overall, these data show at the genome scale how the same TF can be linked to constitutive and inducible gene regulation via distinct combinations of alternative DNA-binding sites. Chromatin immuno-precipitations of transcription factors IRF8, IRF1, PU.1, STAT1, STAT2 and of H3 lysine 27 acetylated followed by multiparallel sequencing, performed in bone marrow-derived macrophages from wild type (WT) and BXH2/TyJ mice. Cells were treated with lipopolysaccharide (LPS) for 2 or 4 hours, or interferon b (IFNb) for 30 or 60 minutes, 2 or 4 hours, or left unstimulated.