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THP1 Human Monocyte cells Project A (part I)

ABSTRACT: Citrate, a central component of cellular metabolism, is a widely used anti-coagulant due to its ability to chelate calcium. Adenosine triphosphate (ATP)-citrate lyase, which metabolizes citrate, has been shown to be essential for inflammation, but the ability of exogenous citrate to impact inflammatory signalling cascades remains largely unknown. We hypothesized that citrate would modulate inflammatory responses as both a cellular metabolite and calcium chelator, and tested this hypothesis by determining how clinically relevant levels of citrate modulate monocyte proinflammatory responses to lipopolysaccharide (LPS) in a human acute monocytic leukaemia cell line (THP-1). In normal medium (0•4 mM calcium), citrate inhibited LPS-induced tumour necrosis factor (TNF)-α and interleukin (IL)-8 transcripts, whereas in medium supplemented with calcium (1•4 mM), TNF-α and IL-8 levels increased and appeared independent of calcium chelation. Using an IL-8–luciferase plasmid construct, the same increased response was observed in the activation of the IL-8 promoter region, suggesting transcriptional regulation. Tricarballylic acid, an inhibitor of ATP-citrate lyase, blocked the ability of citrate to augment TNF-α, linking citrate's augmentation effect with its metabolism by ATP-citrate lyase. In the presence of citrate, increased histone acetylation was observed in the TNF-α and IL-8 promoter regions of THP-1 cells. We observed that citrate can both augment and inhibit proinflammatory cytokine production via modulation of inflammatory gene transactivation. These findings suggest that citrate anti-coagulation may alter immune function through complex interactions with the inflammatory response. Research is published, core data not used but project description is relevant: http://onlinelibrary.wiley.com/doi/10.1111/cei.12591/full

ORGANISM(S): Human Homo Sapiens

TISSUE(S): Mononuclear Cells

SUBMITTER: Maureen Kachman

PROVIDER: ST000172 | MetabolomicsWorkbench | Thu Jun 04 00:00:00 BST 2015

REPOSITORIES: MetabolomicsWorkbench

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Project description:Ascending bacterial infections of the male genitourinary tract by Escherichia coli are an important cause of male infertility. Thus understanding mechanisms by which immunocompetent cells such as testicular macrophages (TM) respond to infection and how bacterial pathogens manipulate defense pathways is of great relevance. Following infection with uropathogenic E. coli (UPEC) whole genome expression profiling revealed induction of the calcium-dependent nuclear factor of activated T cells (NFAT) signaling pathway in TM as well as in peritoneal macrophages (PM) that were used in comparison. UPEC-dependent NFAT activation was confirmed in cultured TM and in TM using an in vivo infection model. Elevated expression of NFATC2-regulated anti-inflammatory cytokines was found in TM (IL-4, IL-13) and PM (IL-3, IL-4, IL-13). NFATC2 is activated by a rapid influx of calcium caused by the UPEC pore forming toxin alpha-hemolysin. Mutant analysis identified alpha-hemolysin as the main virulent factor responsible for UPEC-dependant suppression of IL-6 and TNF-a cytokine release from PM. Alpha-hemolysin caused differential activation of MAP kinase and AP-1 signaling pathways in TM and PM leading to differential expression profiles of key pro-inflammatory cytokines in PM (IL-1a, IL-1b and IL-6 downregulated) and TM (IL-1b and IL-6 upregulated). In contrast to PM, treatment with lipopolysaccharide did not result in activation of the NFkB pathway in TM as shown by lack of degradation of IkBa and lack of pro-inflammatory cytokine secretion (IL-6, TNF-a). In conclusion, these results propose a mechanism how TM can defend against microbes, while at the same time they are able to maintain the immune privileged status of the testis. 2 Macrophage populations ( peritoneal, testicular) infected with UPEC CFT073; timepoints of mrna harvest at 0 min (control), 30 min and 60 min; of each point 2 biological replicates; of each repliccate 2 technical replicates: summa summarum: 2*((1+1+1)*2*2)=24 samples

Project description:Resistance to erythropoietin (EPO) treatment is observed in a considerable proportion of anemic patients with chronic kidney disease. Previous reports suggest that inflammation is one of the major independent predictors of this resistance, and pro-inflammatory cytokines have been shown to inhibit erythropoiesis. The aim of this study was to investigate EPO-induced modification to gene expression in primary cultured leukocytes. Microarray experiments were performed on ex vivo Peripheral Blood Mononuclear Cells (PBMCs) from pooled ten healthy donors (n=9), primed or not with TNF-alpha, and treated with recombinant human erythropoietin alpha (EPO-alpha). Real-time PCR experiments were used to validate expression of the molecular targets considered most relevant for inflammation. Data analysis suggested that EPO-alpha treatment mainly modulated genes involved in cell movement and cell-cell interaction in primed PBMCs. Notably, EPO-alpha exerts anti-inflammatory effects inhibiting the expression of pro-inflammatory cytokine IL-8 and its receptor CXCR2; by contrast, EPO-alpha further increases expression of genes relating to promotion of inflammation encoding for IL-1beta and CCL8, and induces de novo synthesis of IL-1alpha, CXCL1 and CXCL5 in primed PBMCs. MAPK p38alpha?reducing activity is involved in modulation of IL-1beta and IL-8 expression. In conclusion, our findings confirm the anti-inflammatory role for EPO, but also suggest a plausible in vivo scenario, in which the positive correlation found between EPO-resistance and elevated levels of some pro-inflammatory mediators is due to treatment with EPO itself. One future objective will be to perform in vivo measurement of the molecular targets highlighted, in order to identify any additional markers involved in EPO-resistance among hypo-responsive patients. In this study, we analyzed the expression profiles of pooled blood PBMCs from 10 healthy donors primed or not with TNF-alpha and then treated with EPO-alpha. All RNAs from no stimulated PBMCs were hybridized against RNAs from PBMCs treated with TNF-alpha or TNF-alpha and EPO-alpha. We performed a total of 9 technical replicates.

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THP1 Human Monocyte cells Project A (part I)

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