Project description:The goal of this study was to compare the transcriptional responses of mouse macrophages treated with unsaturated or saturated fatty acids to macrophages treated with LPS to stimulate classical inflammatory activation. Microarray profiling was performed on total RNA isolated from primary mouse bone marrow-derived macrophages (BMDMs) treated with fatty acids (C18:1 oleic acid or C18:0 stearic acid), BSA vehicle, or LPS at two time points.
Project description:Obesity leads to a state of chronic low-grade inflammation that features accumulation of lipid-laden macrophages in adipose tissue. Here, we determined the role of macrophage lipid droplet accumulation in the development of obesity-induced adipose tissue inflammation, using mice with myeloid-specific deficiency of the lipid-inducible HILPDA protein. HILPDA deficiency markedly reduced intracellular lipid levels and accumulation of fluorescently-labeled fatty acids. Decreased lipid storage in HILPDA-deficient macrophages could be rescued by inhibition of adipose triglyceride lipase (ATGL) and was associated with increased oxidative metabolism. In diet-induced obese mice, HILPDA deficiency did not alter inflammatory and metabolic parameters, despite markedly reducing lipid accumulation in macrophages. Overall, we find that HILPDA is a lipid-induced physiological inhibitor of ATGL-mediated lipolysis in macrophages that uncouples lipid storage in adipose tissue macrophages from inflammation and metabolic dysregulation. Our data question the contribution of lipid droplet accumulation in adipose tissue macrophages in obesity-induced inflammation and metabolic dysregulation.
Project description:Obesity leads to a state of chronic low-grade inflammation that features accumulation of lipid-laden macrophages in adipose tissue. Here, we determined the role of macrophage lipid droplet accumulation in the development of obesity-induced adipose tissue inflammation, using mice with myeloid-specific deficiency of the lipid-inducible HILPDA protein. HILPDA deficiency markedly reduced intracellular lipid levels and accumulation of fluorescently-labeled fatty acids. Decreased lipid storage in HILPDA-deficient macrophages could be rescued by inhibition of adipose triglyceride lipase (ATGL) and was associated with increased oxidative metabolism. In diet-induced obese mice, HILPDA deficiency did not alter inflammatory and metabolic parameters, despite markedly reducing lipid accumulation in macrophages. Overall, we find that HILPDA is a lipid-induced physiological inhibitor of ATGL-mediated lipolysis in macrophages that uncouples lipid storage in adipose tissue macrophages from inflammation and metabolic dysregulation. Our data question the contribution of lipid droplet accumulation in adipose tissue macrophages in obesity-induced inflammation and metabolic dysregulation.
Project description:Arabidopsis seeds expressing the castor fatty acid hydroxylase accumulate hydroxylated fatty acids up to 17% of total fatty acids in seed triacylglycerols, however total seed oil is also reduced up to 50%. Investigations into the cause of the reduced oil phenotype through in vivo [14C]acteate and [3H]2O metabolic labeling of developing seeds surprisingly revealed that the rate of de novo fatty acid synthesis within the transgenic seeds was approximately half that of control seeds. Addition of castor phospholipid:diacylglycerol acyltransferase (PDAT) increased hydroxylated fatty acid content of the seed oil, increased the rate of fatty acid synthesis, and mostly restored seed oil levels. RNAseq analysis indicated no changes in expression of fatty acid synthesis genes in hydroxylase-expressing plants. Transcript profiles of Arabidopsis developing seeds of three lines, at three stages of development were generated by deep sequencing, in triplicate, using Illumina.
Project description:Consumption of a protein containing meal by a fasted animal promotes protein accretion in skeletal muscle, in part through leucine stimulation of protein synthesis and indirectly through repression of protein degradation mediated by its metabolite, α-ketoisocaproate. Mice lacking the mitochondrial branched-chain aminotransferase (BCATm/Bcat2), that interconverts leucine and α-ketoisocaproate, exhibit elevated protein turnover. Here, the transcriptomes of gastrocnemius muscle from BCATm knockout (KO) and wildtype mice were compared using Next Generation RNA-Sequencing (RNA-Seq) to identify potential adaptations associated with their persistently altered nutrient signaling. Statistically significant changes in the abundance of 1486/~39,010 genes were identified. Bioinformatics analysis of the RNA-Seq data indicated that pathways involved in protein synthesis (eIF2, mTOR, eIF4 and p70S6K pathways including 40S and 60S ribosomal proteins), protein breakdown (e.g., ubiquitin mediated), and muscle degeneration (apoptosis, atrophy, myopathy and cell death) were up-regulated. Also in agreement with our previous observations, the abundance of mRNAs associated with reduced body size, glycemia, plasma insulin, and lipid signaling pathways were observed in BCATm KO mice. Consistently, genes encoding anaerobic and/or oxidative metabolism of carbohydrate, fatty acids and BCAAs were modestly but systematically reduced. Although there was no indication that muscle fiber type was different between KO and wildtype mice, a difference in the abundance of mRNAs associated with a muscular dystrophy phenotype was observed, consistent with the published exercise intolerance of these mice. The results suggest transcriptional adaptations occur in BCATm KO mice that along with altered nutrient signaling may contribute to their previously reported protein turnover, metabolic and exercise phenotypes. Comparison of wildtype and BCATm KO gastrocnemius biological replicates
Project description:Expression data from cultured mouse macrophages isolated from Hilpdaflox/flox (WT) and HilpdaΔMΦ (KO) mice treated with a mixture of fatty acids
Project description:Arabidopsis seeds expressing the castor fatty acid hydroxylase accumulate hydroxylated fatty acids up to 17% of total fatty acids in seed triacylglycerols, however total seed oil is also reduced up to 50%. Investigations into the cause of the reduced oil phenotype through in vivo [14C]acteate and [3H]2O metabolic labeling of developing seeds surprisingly revealed that the rate of de novo fatty acid synthesis within the transgenic seeds was approximately half that of control seeds. Addition of castor phospholipid:diacylglycerol acyltransferase (PDAT) increased hydroxylated fatty acid content of the seed oil, increased the rate of fatty acid synthesis, and mostly restored seed oil levels. RNAseq analysis indicated no changes in expression of fatty acid synthesis genes in hydroxylase-expressing plants.