Project description:Macrophages stimulated with lipopolysaccharide (LPS) plus interferon-g (IFNg) accumulate TGs in LDs, and long-chain acylcarnitines. Inhibition of TG synthesis results in diminished LD development, and increased long chain acylcarnitine levels, suggesting that FA fate is balanced between TG and acylcarnitine synthesis. Nevertheless, TG-synthesis is required for inflammatory macrophage function, since its inhibition negatively affects production of proinflammatory IL-1b, IL-6 and PGE2, and phagocytic capacity, and protects against LPS-induced sock in vivo.
Project description:This SuperSeries is composed of the following subset Series: GSE30971: The Histone Methyltransferase Wbp7 Controls Macrophage Function through GPI Glycolipid Anchor Synthesis. [Expression Profile] GSE30972: The Histone Methyltransferase Wbp7 Controls Macrophage Function through GPI Glycolipid Anchor Synthesis. [ChIP_seq] Refer to individual Series
Project description:Altered lipid metabolism in macrophages is associated with various important inflammatory conditions. Although lipid metabolism is an important target for therapeutic intervention, the metabolic requirement involved in lipid accumulation during pro-inflammatory activation of macrophages remains incompletely characterized. We show here that macrophage activation with IFNγ results in increased aerobic glycolysis, iNOS-dependent inhibition of respiration, and accumulation of triacylglycerol. Surprisingly, metabolite tracing with 13C-labeled glucose revealed that the glucose contributed to the glycerol groups in triacylglycerol (TAG), rather than to de novo synthesis of fatty acids. This is in stark contrast to the otherwise similar metabolism of cancer cells, and previous results obtained in activated macrophages and dendritic cells. Our results establish a novel metabolic pathway whereby glucose provides glycerol to the headgroup of TAG during classical macrophage activation.
Project description:IFN-g primes macrophages for enhanced inflammatory activation by TLRs and microbial killing, but little is known about the regulation of cell metabolism or mRNA translation during priming. We found that IFN-g regulates macrophage metabolism and translation in an integrated manner by targeting mTORC1 and MNK pathways that converge on the selective regulator of translation initiation eIF4E. Physiological downregulation of the central metabolic regulator mTORC1 by IFN-g was associated with autophagy and translational suppression of repressors of inflammation such as HES1. Genome-wide ribosome profiling in TLR2-stimulated macrophages revealed that IFN-g selectively modulates the macrophage translatome to promote inflammation, further reprogram metabolic pathways, and modulate protein synthesis. These results add IFN-g-mediated metabolic reprogramming and translational regulation as key components of classical inflammatory macrophage activation. RPF and RNAseq libraries were generated from mock or IFN-g-primed human macrophages. Cells were stimulated with Pam3Cys and harvested at 4 hours. Libraries were generated using protocol modified from Illumina Truseq technology.
Project description:IFN-g primes macrophages for enhanced inflammatory activation by TLRs and microbial killing, but little is known about the regulation of cell metabolism or mRNA translation during priming. We found that IFN-g regulates macrophage metabolism and translation in an integrated manner by targeting mTORC1 and MNK pathways that converge on the selective regulator of translation initiation eIF4E. Physiological downregulation of the central metabolic regulator mTORC1 by IFN-g was associated with autophagy and translational suppression of repressors of inflammation such as HES1. Genome-wide ribosome profiling in TLR2-stimulated macrophages revealed that IFN-g selectively modulates the macrophage translatome to promote inflammation, further reprogram metabolic pathways, and modulate protein synthesis. These results add IFN-g-mediated metabolic reprogramming and translational regulation as key components of classical inflammatory macrophage activation. microRNA-seq libraries were generated from mock or IFN-g-primed human macrophages. Cells were stimulated with or without Pam3Cys and harvested at 4 hours Libraries were generated using Illumina Truseq small RNA technology.
Project description:Abstract: Atherosclerotic cardiovascular disease (CVD) is the leading cause of death in the developed world and is characterized by both chronic low-grade inflammation and dyslipidemia. AMP-activated protein kinase (AMPK) inhibits cholesterol synthesis and dampens inflammation. While activation of AMPK has been shown to have beneficial effects on aspects of atherosclerosis, to date, only compounds that indirectly and non-specifically activate the kinase (i.e. metformin, canagliflozin, salsalate) or have low oral and cellular bioavailability (i.e. A769662) have been examined. In the current study, we have tested the effects of an orally bioavailable and potent activator of AMPK, PF-06409577, that selectively targets AMPKb1-containing complexes which are predominately expressed in the murine liver and immune cells, including macrophages. We found that daily oral gavage with PF-06409577 reduced levels of atherosclerotic plaque in two models of atherosclerosis through a mechanism dependent on the AMPKb1 isoform in myeloid cells. These observations were not associated with changes in hepatic or plasma lipid levels but instead was associated with reductions in inflammatory pathways in macrophages. In cultured bone marrow-derived macrophages, PF-06409577 activated AMPK and reduced inflammatory pathways including the NF-κB pathway as well as fatty acid and cholesterol synthesis; effects requiring the AMPKβ1 isoform. These data indicate that pharmacologically targeting macrophage AMPKβ1 may be a promising strategy for reducing atherosclerosis.
Project description:Macrophage polarization between the M2 (repair, pro-tumorigenic) and M1 (inflammatory) phenotypes is seen as a continuum of states. The detailed transcriptional events and signals downstream of CSF-1R that contribute to amplification of the M2 phenotype and suppression of the M1 phenotype are largely unknown. Macrophage CSF-1R pTyr-721 signaling promotes cell motility and enhancement of tumor cell invasion in vitro. Combining analysis of cellular systems for CSF-1R gain-of-function and loss-of-function with bioinformatic analysis of the macrophage CSF-1R pTyr-721-regulated transcriptome, we uncovered miR-21 as a downstream molecular switch controlling macrophage activation and identified ERK1/2 and NF-M-NM-:B as CSF-1R pTyr-721-regulated signaling nodes. We show that CSF-1R pTyr-721 signaling suppresses the proinflammatory phenotype, predominantly by induction of miR-21. Profiling of the miR-21-regulated mRNAs revealed that 80% of the CSF-1-regulated canonical miR-21 targets are pro-inflammatory molecules. Additionally, miR-21 positively regulates M2 marker expression. Moreover, miR-21 feeds back to positively regulate its own expression and to limit CSF-1R-mediated activation of ERK1/2 and NF-M-NM-:B. Consistent with an anti-inflammatory role of miRNA-21, intraperitoneal injection of mice with a miRNA-21 inhibitor increases the recruitment of inflammatory monocytes and enhances the peritoneal monocyte/macrophage response to lipopolysaccharide (LPS). M-bM-^@M-^C These results identify the macrophage miR-21 network as a novel target for controlling macrophage polarization. We performed microarray-based analysis on four mouse macrophage cell lines, two CSF-1R pTyr-721-expressing cell lines (M-/-.WT and M-/-.3ABY721) and two CSF-1R Tyr-721-deficient lines (M-/-.Y721F and M-/-.3AB). Total RNA (two biological replicates) was extracted from CSF-1-starved cells (UR) or from cells constitutively grown in CSF-1 (CONST). Additionally, CSF-1-starved M-/-.WT and M-/-.Y721F cell lines were stimulated with CSF-1 for 0min, 20 min, 60 min and 180 min and used for total RNA extraction. Total RNA preparations with Ribosomal Integrity Numbers (RIN) > 9.5 were used for microarray analysis. A total of 100 ug/cell line/replicate was used for gene expresion analysis on the Affymetrix Mouse Gene ST1.0 chips at the Genomics Core at Einstein, according to manufacturerM-bM-^@M-^Ys instructions. Differential expression analysis was performed using the M-bM-^@M-^XlimmaM-bM-^@M-^Y package of R/Bioconductor to identify significantly differentially expressed mRNAs over time, in response to CSF-1 treatment and to the genotype. CSF1-regulated genes were identified according to the cutoff with both expression folder change > 1.5 and p-value < 0.05.