Project description:Macrophages (MФ) skewn towards a regulatory-like phenotype are known to promote tumor progression. They tend to accumulate in hypoxic tumor areas and activate hypoxia-inducible factors (HIF-1 and HIF-2). HIFs are known to alter the gene expression profile of MФ. To define direct HIF-1 and HIF-2 target genes in hypoxic and IL-10 treated human MФ we used chromatin immuno-precipitation-sequencing (ChIP-seq) and microarray analysis on a genome-wide scale.
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:Background: Obesity is associated with infiltration of macrophages into adipose tissue. Adipose macrophages may contribute to an elevated inflammatory status by secreting a variety of pro-inflammatory mediators, including TNFalpha and IL-6. Recent data suggest that during diet-induced obesity the phenotype of adipose-resident macrophages changes from alternatively activated macrophages towards a more classical and pro-inflammatory phenotype. Here, we explore the effect of PPARγ-activation on obesity-induced inflammation in 129SV mice fed a high fat diet for 20 weeks. High fat feeding increased bodyweight gain, adipose tissue mass and liver triglycerides. Rosiglitazone treatment further increased adipose mass, reduced liver triglycerides and changed adipose tissue morphology towards smaller adipocytes. Surprisingly, rosiglitazone markedly increased the number of macrophages in adipose tissue, as shown by immunohistochemical analysis and quantification of macrophage marker genes CD68 and F4/80+. In adipose tissue, markers for classically activated macrophages including IL-18 were down regulated whereas markers characteristic for alternatively activated macrophages (Arginase 1, IL-10) were up regulated by rosiglitazone. Importantly, conditioned media from rosiglitazone-treated alternatively activated macrophages neutralized the inhibitory effect of macrophages on 3T3-L1 adipocyte differentiation, suggesting that alternatively activated macrophages may be involved in mediating the effects of rosiglitazone on adipose tissue morphology and mass. Our results suggest that short term rosiglitazone treatment increases infiltration of alternatively activated macrophages in adipose tissue. The alternatively activated macrophages might play a role in PPARγ-dependent expansion and remodeling of adipose tissue. Keywords: metabolic state analysis
Project description:Background: Obesity is associated with infiltration of macrophages into adipose tissue. Adipose macrophages may contribute to an elevated inflammatory status by secreting a variety of pro-inflammatory mediators, including TNFalpha and IL-6. Recent data suggest that during diet-induced obesity the phenotype of adipose-resident macrophages changes from alternatively activated macrophages towards a more classical and pro-inflammatory phenotype. Here, we explore the effect of PPARγ-activation on obesity-induced inflammation in 129SV mice fed a high fat diet for 20 weeks. High fat feeding increased bodyweight gain, adipose tissue mass and liver triglycerides. Rosiglitazone treatment further increased adipose mass, reduced liver triglycerides and changed adipose tissue morphology towards smaller adipocytes. Surprisingly, rosiglitazone markedly increased the number of macrophages in adipose tissue, as shown by immunohistochemical analysis and quantification of macrophage marker genes CD68 and F4/80+. In adipose tissue, markers for classically activated macrophages including IL-18 were down regulated whereas markers characteristic for alternatively activated macrophages (Arginase 1, IL-10) were up regulated by rosiglitazone. Importantly, conditioned media from rosiglitazone-treated alternatively activated macrophages neutralized the inhibitory effect of macrophages on 3T3-L1 adipocyte differentiation, suggesting that alternatively activated macrophages may be involved in mediating the effects of rosiglitazone on adipose tissue morphology and mass. Our results suggest that short term rosiglitazone treatment increases infiltration of alternatively activated macrophages in adipose tissue. The alternatively activated macrophages might play a role in PPARγ-dependent expansion and remodeling of adipose tissue. Keywords: metabolic state analysis Pure bred wild-type (129S1/SvImJ) male mice received a low fat diet or high fat diet for 21 weeks, providing 10 or 45% energy percent in the form of triglycerides (D12450B or D12451, Research Diets, New Brunswick, USA). The lard component in these diets was replaced by palm oil. In the last week of diet intervention, half of the mice receiving the HFD were switched to HFD supplemented with Rosiglitazone (0.01 % wt/wt). Animals were sacrificed in the fed state. Epididymal adipose tissue was excised and frozen in liquid nitrogen. Pooled RNA samples from 5 mice per experimental group were used for microarray analysis. Samples were hybridized on Affymetrix GeneChip Mouse Genome 430-2.0 plus arrays. Five microgram total RNA was labelled according to the Affymetrix One-cycle Target Labeling Assay, fragmented and hybridized according to Affymetrix's protocols.
Project description:This SuperSeries is composed of the following subset Series: GSE16385: Expression data from human macrophages GSE16386: Expression data from human alternatively activated macrophages GSE25088: PPARg and IL-4-induced gene expression data from wild-type and STAT6 knockout mouse bone marrow-derived macrophages GSE25123: PPARg and IL-4-induced gene expression data from PPARg +/- LysCre and PPARg fl/- LysCre mouse bone marrow-derived macrophages GSE25125: PPARg and IL-4-induced gene expression data from PPARg +/- LysCre and PPARg fl/- LysCre mouse bone marrow-derived alternatively activated macrophages and immature dendritic cells (iDCs) Refer to individual Series
Project description:Analysis of the binding sites of Hif-1α in both wild-type and von Hippel Lindau mutant zebrafish lines at 4dpf by ChIP linked next generation sequencing. The von Hippel Lindau mutant displays a systemic hypoxic response under normoxic conditions. Results show the extent of Hif-1α binding to the genome, and provide a basis for analysis of the transcriptional response to genetically induced hypoxia in zebrafish. Analysis of the DNA binding sites of Hif-1α in both wild-type and von Hippel Lindau mutant zebrafish lines at 4dpf. The von Hippel Lindau mutant displays a systemic hypoxic response under normoxic conditions. Results show the extent of Hif-1α binding to the genome, and provide a basis for analysis of the dependency of the transcriptional response on Hif-1α in conditions of genetically induced hypoxia in zebrafish.
Project description:To investigate how LXR activation potentiates expression of Th2 cytokine-dependent genes in primary human macrophages, we pulsed macrophages with synthetic LXR ligand T0901317 then polarized cells to alternatively activated macrophages with IL-4 or IL-13.
Project description:A potent Th1 immune response is critical to the control of tuberculosis. The impact of an additive Th2 response on the course of disease has so far been insufficiently characterized, despite increased morbidity after coinfection with Mycobacterium tuberculosis and Th2 eliciting helminths and possible involvement of Th2 polarization in reactivation of latent tuberculosis. Here, we describe the gene expression profile of murine bone marrow derived macrophages alternatively activated by IL-4 to infection with M. tuberculosis. Comparison of transcriptional profiles of infected IL-4 and IFN-g activated macrophages revealed delayed and partially diminished responses in alternatively activated macrophages, characterized by reduced exposure to nitrosative stress and increased iron availability, respectively, to intracellular bacteria. Alternative activation of host macrophages correlated with elevated expression of the M. tuberculosis iron storage protein bfrB as well as reduced expression of the mycobactin synthesis genes mbtI and mbtJ. The extracellular matrix remodelling enzyme matrix metalloproteinase-12 (MMP-12) was induced in alternatively activated macrophages in vitro, and MMP-12 expressing macrophages were abundant at late, but not early, stages of tuberculosis in murine lungs. Our findings emphasize that alternative activation deprives macrophages of control mechanisms which limit mycobacterial growth in vivo, thus supporting intracellular persistence of M. tuberculosis. Keywords: transcriptome, gene regulation, macrophages, IL-4, IFN-gamma, nitric oxide