ABSTRACT: PPARg is a nuclear receptor that plays an important role in lipid metabolism, homeostasis and immunity. Microarray analysis of gene expression was performed in macrophages from WT and PPARg KO mice. Differentially expressed genes were selected for further analysis. RNA from WT and PPARg KO macrophages was purified for hybridization on Affymetrix microarrays. Peritoneal macrophages were harvest from WT and PPARg KO mice 3 days after intraperitoneal injection of 2.5ml of 3% thioglycollate.
Project description:The nuclear receptor Peroxisome Proliferator Activator Receptor (PPAR ) is the target of antidiabetic thiazolidinedione drugs, which improve insulin resistance but have side-effects that limit widespread use. PPAR is required for adipocyte differentiation, but is also expressed in other cell types, notably macrophages, where it influences atherosclerosis, insulin resistance, and inflammation. A central question is whether PPAR binding in macrophages occurs at the same or different genomic locations compared to adipocytes. Here, utilizing chromatin immunoprecipitation and high throughput sequencing (ChIP-seq), we demonstrate that PPAR cistromes in adipocytes and macrophages are predominantly cell type specific. In macrophages, PPAR colocalizes with the hematopoietic transcription factor PU.1 in areas of open chromatin and histone acetylation, near a distinct set of immune genes in addition to a number of metabolic genes shared with adipocytes. In adipocytes, the macrophage-unique binding regions are marked with repressive histone modifications, typically associated with local chromatin compaction and gene silencing. PPAR , when introduced into cells that are neither macrophages nor adipocytes, bound only to regions depleted of repressive histone modifications, where it increased DNA accessibility, enhanced histone acetylation, and induced gene expression. Thus, the cell-specificity of PPAR function is regulated by cell-specific chromatin accessibility, histone marks, and transcription factors. Genomic occupancy profiled by high throughput sequencing (ChIP-seq) from mouse macrophages for PPARgamma, PU.1, C/EBPbeta, H3K9Ace; and from 3T3-L1 adipocytes for PPARgamma and H3K9Ace Masking file used to subtract input bias areas prior to generating final peak lists is linked below.
Project description:Macrophages are a major cellular component of all inflammatory situations, generating proinflammatory cytokines such as TNF-alpha, IL-1, and IL-6 that are central to the initiation and maintenance of inflammation. To determine whether the tumor suppressor ARF plays a role in inflammatory gene expression, we used an 84-gene RT2 PCR array to examine the expression of inflammation-associated genes in WT and ARF-deficient macrophages treated with the TLR4 ligand LPS. Peritoneal macrophages from WT and ARF-deficient mice were obtained and treated with LPS (200ng/ml) for 4 hours. WT control (without stimulation n=4), WT LPS (n=4), ARF Control (n=4), ARF LPS (n=4)
Project description:Data from nuclear receptors RXR and PPARg binding to the genome was visualized using Genome Browser (UCSC) in order to test their role in Mafb transcriptional regulation RXR and PPARg ChIP was performed in thioglycollate-elicited peritoneal macrophages in basal conditions
Project description:LPS-stimulated macrophages from Pac1+/+ and Pac1-/- mice were compared to assess gene expression changes in the absence of PAC-1 (also known as Dual specificity phosphatase 2). Experiment Overall Design: Age matched Pac1+/+ and Pac1-/- littermates were used to obtain equal numbers of thiolycollate-elicited macrophages. Pure populations of macrophages were stimulated with 100 ng/ml of LPS for 6 hours. 6 hours was chosen to assess mainly inflammatory gene expression.
Project description:Macrophage activation must be tightly controlled to prevent overzealous responses that cause self-damage. MicroRNAs have been shown to promote classical macrophage activation by blocking concomitant anti-inflammatory signals and transcription factors, but can also place restraints on activation by preventing excessive TLR-signalling. In contrast, the microRNA profile associated with alternatively activated macrophages and their role in regulating wound-healing or anti-helminthic responses has not yet been described. Utilizing an in vivo model of alternative activation, in which adult Brugia malayi nematodes are surgically implanted in the peritoneal cavity of mice, we examined the profile of microRNA expression in these alternatively activated macrophages and compared this to alternatively activated IL-4 receptor knockout macrophages and thioglycollate elicited macrophages. Peritoneal macrophages from BALB/c wild type or IL-4 receptor knockout mice were elicited with thioglycollate or using nemtodes (peritoneal implant of Brugia malayi). The latter leads to a population of alternatively activated macrophages. Microarray analysis was used to examine the microRNA profile of WT alternatively activated macrophages (n = 4), IL-4 receptor knockout alternatively activated macrophages (n = 4), WT thioglycollate elicited macrophages (n = 3) and IL-4 receptor knockout thioglycollate elicited macrophages (n = 3).
Project description:Setdb1 is one of the H3K9 methyltransferases and represses gene expression by H3K9 methylation. In an attempt to elucidate the role of Setdb1 in the TLR4-mediated inflammatory responses, we performed DNA microarray analysis using lipid A (the active component of LPS)-stimulated peritoneal macrophages from macrophage specific Setdb1 KO (KO) and WT mice. The genes upregulated by lipid A treatment in WT macrophages and further increased in KO macrophages contain many genes associated with interleukins and chemokines. Peritoneal macrophages from WT and KO mice were stimulated with lipid A 10 ng/ml or vehicle for 4 h. Microarray analysis was performed using Affymetrix Mouse 430 2.0.
Project description:Biologic functions involved in innate immune response of macrophages rely on the precise regulation of kinds of immune molecular. In the virus infection procession, the macrophages are activated following a tightly controlled genetic programme where specific sets of genes are up-regulated or down-regulated. We used microarrays to detail the global programme of gene expression underlying VSV infection and identified distinct classes of up-regulated and down-regulated genes during this process. Mouse peritoneal macrophages were selected with/without VSV infection for 8 hours for RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain expression profiles. We selected macrophages according to VSV infection at two time-points: uninfected macrophage(control) and VSV infected for 8 hour macrophages(VSV).
Project description:HDAC11 regulates IL-10 expression and overexpression of HDAC11 in antigen presenting cells (APCs) leads to a pro-inflammatory phenotype. Conversely, loss of HDAC11 leads to upregulation of IL-10 and immune tolerance. HDAC11 overexpression is also associated with inflammatory diseases including multiple sclerosis. Hence we wished to determine the inflammatory mediators regulated by HDAC11. We used microarray to determine gene expression profile of macrophages from WT and HDAC11 knockout mice. Thioglycollate induced-peritoneal macrophages obtained from WT and HDAC11 knockout mice were used for total RNA extraction to determine changes in gene expression levels in macrophages from WT and HDAC11 knockout mice.
Project description:Vascular disrupting agents (VDA) represent a novel approach to the treatment of cancer, resulting in collapse of tumor vasculature and tumor death. 5,6-Dimethylxanthenone-4-acetic acid (DMXAA) is a VDA currently in advanced Phase II clinical trials, yet its precise mechanism of action is unknown despite extensive preclinical and clinical investigations. The data presented herein demonstrate that DMXAA is a novel and specific activator of the TBK1-IRF-3 signaling pathway. DMXAA treatment of primary murine macrophages resulted in robust IRF-3 activation, a ~750-fold increase in IFN-beta mRNA and, in contrast to the potent Toll-like receptor 4 (TLR4) agonist, lipopolysaccharide (LPS), signaling was independent of mitogen-activated protein kinase (MAPK) activation and elicited minimal NF-kappaB-dependent gene expression. DMXAA-induced signaling was critically dependent on the IRF-3 kinase, TBK1, and IRF-3, but MyD88-, TRIF-, IPS-1/MAVS-, and IKKbeta-independent, thus excluding all known TLRs and cytosolic helicase receptors. DMXAA pretreatment of murine macrophages induced a state of tolerance to LPS and vice versa. In contrast to LPS stimulation, DMXAA-induced IRF-3 dimerization and IFN-beta expression were inhibited by salicylic acid (SA). These findings detail a novel pathway for TBK-1-mediated IRF-3 activation and provide new insights into the mechanism of this new class of chemotherapeutic drugs. Experiment Overall Design: Microarray analysis was carried out using Affymetrix® mouse array 430A_2 exposed to total RNA prepared from C57BL/6J or IFN-beta-/- macrophages that had been treated with medium alone or DMXAA for 3 h. Fold-induction was calculated using Affymetrix® GeneChip® Operating Software. A >3-fold increase or decrease between inducible and basal mRNA levels was set as the criteria for inclusion of a gene as modulated.
Project description:Lipopolysaccharide (LPS), a Toll-like receptor (TLR) 4 ligand, induces the expression of various genes including proinflammatory cytokines, and the expression is modified by the presence of Zc3h12a. We used microarrays to examine influence of Zc3h12a deficiency in LPS-inducible gene expression. Experiment Overall Design: Peritoneal macrophages from wild-type and Zc3h12a-/- mice were stimulated with LPS for 0, 1, 2 and 4 hours, followed by RNA extraction. Then hybridization on affymetrix microarrays was performed.