Human transcriptome analysis of acute responses to glucose ingestion reveals a role of leukocytes in hyperglycemia induced inflammation.
ABSTRACT: Objective was to examine acute gene expression responses to physiologic oral glucose ingestion in human circulating leukocytes. Microarray study of human circulating leukocytes sampled before, 1 hour after and 2 hours after glucose ingestion was performed. The present study demonstrated 36 genes which showed acute gene expression change in human leukocytes within 1 hour after glucose ingestion and suggest that leukocytes participate in the inflammatory process induced by acute hyperglycemia. Microarray study of human circulating leukocytes sampled before, 1 hour after and 2 hours after glucose ingestion
Project description:A single bout of exercise followed by intake of carbohydrates leads to glycogen supercompensation in the prior exercised muscle. The molecular mechanisms underlying this well-known phenomenon remain elusive. Here we report that a single bout of exercise induces marked activation of glycogen synthase (GS) and AMP-activated protein kinase (AMPK) for several days beyond normalized muscle glycogen content in man. Acute muscle specific deletion of AMPK activity in mouse muscle abrogated the ability for glycogen supercompensation, providing genetic evidence that AMPK serves as essential driver for glycogen supercompensation. Muscle proteomic analyses revealed elevated glucose uptake capacity in the prior exercised muscle while key proteins in fat oxidation and glycolysis largely remained unchanged. The temporal order of these sustained cellular alterations induced by a single bout of exercise provide a mechanism to offset the otherwise tight feedback inhibition of glycogen synthesis and glucose uptake by glycogen, ultimately leading to muscle glycogen supercompensation.
Project description:Rationale: Obstructive sleep apnea (OSA) has been associated with a number of chronic disorders that may improve with effective therapy. However, the molecular pathways affected by continuous positive airway pressure (CPAP) treatment are largely unknown. We sought to assess the system-wide consequences of CPAP therapy by transcriptionally profiling peripheral blood leukocytes (PBLs). Methods: Subjects diagnosed with severe OSA were treated with CPAP, and whole-genome expression measurement of PBLs was performed at baseline and following therapy. We used Gene Set Enrichment Analysis (GSEA) to identify gene sets that were differentially enriched. Network analysis was then applied to identify key drivers of pathways influenced by CPAP. Results: 18 subjects with severe OSA (apnea hypopnea index ≥ 30 events/hour) underwent CPAP therapy and microarray analysis of their PBLs. Treatment with CPAP improved AHI, daytime sleepiness and blood pressure but did not affect anthropometric measures. GSEA revealed a number of enriched gene sets, many of which were involved in neoplastic processes and displayed down-regulated expression patterns in response to CPAP. Network analysis identified several densely connected genes that are important modulators of cancer and tumor growth. Conclusions: Effective therapy of OSA with CPAP is associated with alterations in circulating leukocyte gene expression. Functional enrichment and network analyses highlighted transcriptional suppression in cancer-related pathways suggesting potentially novel mechanisms linking OSA with neoplastic signatures. Total RNA from peripheral blood leukocytes of 18 subjects with severe sleep apnea at baseline and after effective CPAP therapy was hybridized to 36 Affymetrix Genechip Human Gene 1.0 ST microarrays
Project description:Resveratrol is a naturally occurring compound that profoundly affects energy metabolism and mitochondrial function and serves as a calorie restriction mimetic, at least in animal models of obesity. Here we treated 10 healthy, obese men with placebo and 150 mg/day resveratrol in a randomized double-blind cross-over study for 30 days. Resveratrol supplementation significantly reduced sleeping- and resting metabolic rate. In muscle, resveratrol activated AMPK, increased SIRT1 and PGC-1alpha protein levels, increased citrate synthase activity, and improved muscle mitochondrial respiration on a fatty acid-derived substrate. Furthermore, resveratrol elevated intramyocellular lipid levels, and decreased intrahepatic lipid content, circulating glucose, triglycerides, alanine-aminotransferase, and inflammation markers. Systolic blood pressure dropped and HOMA index improved after resveratrol. In the postprandial state, adipose tissue lipolysis and plasma fatty acid and glycerol decreased. In conclusion, we demonstrate that 30 days of resveratrol supplementation induces profound metabolic changes in obese subjects, mimicking the effects of calorie restriction. double-blind randomized cross-over study, Expression profiling by microarray
Project description:The goal was to measure the postprandial effect of an oat bran meal on gene expression in leukocytes from healthy subjects and to investigate the postprandial glucose, insulin and triglyceride responses. Linear mixed models were used for the array data to study the simultaneous dependency on many factors and functional categories of genes whose expression were correlated with oat bran intake were determined.
Project description:Dietary fat quality may influence skeletal muscle lipid handling and fat accumulation, thereby modulating insulin sensitivity. Objective: To examine acute effects of meals with various fatty acid (FA) compositions on skeletal muscle FA handling and postprandial insulin sensitivity in obese insulin resistant men. Design: In a single-blinded randomized crossover study, 10 insulin resistant men consumed three high-fat mixed-meals (2.6MJ). Meals were high in saturated FA (SFA), in monounsaturated FA (MUFA) or in polyunsaturated FA (PUFA). Fasting and postprandial skeletal muscle FA handling were examined by measuring arterio-venous concentration differences across forearm muscle. [2H2]-palmitate was infused intravenously to label endogenous triacylglycerol (TAG) and FFA in the circulation and [U-13C]-palmitate was added to the meal to label chylomicron-TAG. Skeletal muscle biopsies were taken to assess intramuscular lipid metabolism and gene expression. Results: Insulin and glucose responses (AUC) after SFA meal were significantly higher compared with PUFA meal (p=0.003 and 0.028, respectively). Uptake of TAG-derived FA was significantly lower in the early postprandial phase after PUFA meal as compared with other meals (AUC60-120, p<0.001). The PUFA meal induced less transcriptional downregulation of oxidative pathways compared with other meals. The fractional synthetic rate was higher in DAG and PL fraction after MUFA and PUFA meal. Conclusion: Intake of a PUFA meal reduced TAG-derived skeletal muscle FA uptake, which was accompanied by higher postprandial insulin sensitivity and a tendency towards a higher muscle lipid turnover. These data suggest that the effects of replacement of SFA by PUFA may contribute to less muscle lipid uptake and may be therefore protective against the development of insulin resistance. Keywords: expression profiling by array randomized crossover dietary intervention study
Project description:Background: Exercising is know to have an effect on exercising skeletal muscle, but unkown is the effect on non-exercising skeletal muscle. Gene expression changes in the non-exercising skeletal muscle would point to a signalling role of skeletal muscle 9 healthy middle-aged men performed 1 hour of one-legged exercise, before and afterwards muscle biopsies were taken from both legs. Skeletal muscle biopsies were analyzed by microarray.
Project description:Monocytes play a central role in the inflammatory response that follows acute myocardial infarction (MI). In order to study phenotypic adaptation of this cell type, we investigated patterns of monocyte gene expression in circulating monocytes at various stages of MI. Circulating monocytes were isolated from venous blood of MI patients at three time points: t1: within 6 hours after onset of chest pain (acute phase), t2: 3 days after MI (subacute phase), t3: 90 days after MI (chronic phase). For comparison, we studied a control group (n=21, data to be submitted later) with stable coronary artery disease. Using this transcriptomic analysis, we aimed to provide a more comprehensive reference of monocyte biology following acute MI and to aid in the identification of novel pathways and genes influencing the course of MI. Monocytes play a central role in the inflammatory response that follows acute myocardial infarction (MI). In order to study phenotypic adaptation of this cell type, we investigated patterns of monocyte gene expression in circulating monocytes at various stages of MI. Circulating monocytes were isolated from venous blood of MI patients at three time points: t1: within 6 hours after onset of chest pain (acute phase), t2: 3 days after MI (subacute phase), t3: 90 days after MI (chronic phase). For comparison, we studied a control group (n=21, data to be submitted later) with stable coronary artery disease. Illumina Ref-8 v3.0 microarray arrays were used for whole-genome transcriptional profiling.
Project description:Untreated HIV-1 infection progresses through acute and asymptomatic stages to AIDS. While each of the three stages has well-known clinical, virologic and immunological characteristics, much less is known of the molecular mechanisms underlying each stage. Here we report lymphatic tissue microarray analyses revealing for the first time stage-specific patterns of gene expression during HIV-1 infection. We show that while there is a common set of key genes with altered expression throughout all stages, each stage has a unique gene-expression signature. The acute stage is most notably characterized by increased expression of hundreds of genes involved in immune activation, innate immune defenses (e.g.MDA-5, TLR-7 and -8, PKR, APOBEC3B, 3F, 3G), adaptive immunity, and in the pro-apoptotic Fas-Fas-L pathway. Yet, quite strikingly, the expression of nearly all acute-stage genes return to baseline levels in the asymptomatic stage, accompanying partial control of infection. In the AIDS stage, decreased expression of numerous genes involved in T cell signaling identifies genes contributing to T cell dysfunction. These common and stage-specific, gene-expression signatures provide new insights into the molecular mechanisms underlying the host response and the slow, natural course of HIV-1 infection. Experiment Overall Design: A total of 52 patients were analyzed: 10 patients unaffected, 18 patients with asymptomatic stages of AIDs, 16 patients with acute stages of AIDs, and 8 patients with AIDs.
Project description:Adipose tissue is a major target of GH action. GH stimulates lipolysis and reduces fat mass. The molecular mechanism underlying cellular and metabolic effects of GH in adipose tissue is not well understood. The aim of this study is to identify GH-responsive genes that regulate lipid metabolism in adipose tissue. Eight men with GH deficiency underwent measurement of plasma free fatty acid (FFA), whole body lipid oxidation and fat biopsies before and after one month of GH treatment (0.5mg/day). Gene expression profiling was performed using Agilent 44K G4112F arrays utilising a two-colour design. Differentially expressed genes were identified using an empirical Bayes, moderate t-test, with a false discovery rate of < 5%. Genes involved in GH receptor signalling, lipolysis, triglyceride biosynthesis, adipocyte differentiation and function were analysed. Target genes were validated by quantitative RT-PCR. GH increased circulating IGF-I and FFA and stimulated fat oxidation. A total of 246 genes were differentially expressed, of which 135 were up-regulated and 111 down-regulated. GH enhanced adipose tissue expression of IGF-I and SOCS3. It did not change expression of key enzymes governing lipolysis, but differentially regulated genes promoting diacylglycerol syntheses. GH repressed hydroxysteroid (11-beta) dehydrogenase 1, which activates local cortisol production, and genes encoding components of extracellular matrix that regulate inflammation. GH induced concordant change in circulating IGF-I and expression in adipose tissue. GH stimulation of lipolysis is mediated at a translational and/or post-translational level. GH suppressed genes encoding local factors regulating adipocyte differentiation, function and inflammation.