The M1 and the M2 macrophage polarization programs (activated by IFN? and IL-4, respectively) lie at the opposite edges of a continuum of activation states but are frequently co-activated during co-infections and in cancer despite controlling divergent functional responses. Whether these two programs are mutually exclusive, how they influence each other, and whether one represents the prevailing response, are all open questions. Co-administration of IFN? and IL-4 exerted complex inhibitory effects over the M1 and M2 programs at the level of both epigenomic and transcriptional changes. Computational data mining and validation analyses revealed the molecular basis of the differential sensitivity of genes and cis-regulatory elements to the antagonistic effects of the opposite stimulus. For instance, while STAT1 and IRF motifs were associated with robust and IL-4-resistant responses to IFN?, their coexistence with binding sites for some auxiliary transcription factors such as AP-1, generated vulnerability to IL-4-mediated inhibition. These data provide a core mechanistic framework for the integration of signals that control macrophage activation and the starting point for understanding macrophage responses in complex environmental conditions Overall design: Analysis of transcriptional and epigenomic changes in mouse macrophages stimulated with different cytokines or their combinations
Opposing macrophage polarization programs show extensive epigenomic and transcriptional cross-talk.
Specimen part, Cell line, Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The histone methyltransferase Wbp7 controls macrophage function through GPI glycolipid anchor synthesis.
Specimen part, Treatment
View SamplesHistone methyltransferases catalyze site-specific deposition of methyl groups, enabling recruitment of transcriptional regulators. In mammals, trimethylation of lysine 4 in histone H3, a modification localized at the transcription start sites of active genes, is catalyzed by six enzymes (SET1a and SET1b, MLL1MLL4) whose specific functions are largely unknown. By using a genomic approach, we found that in macrophages, MLL4 (also known as Wbp7) was required for the expression of Pigp, an essential component of the GPI-GlcNAc transferase, the enzyme catalyzing the first step of glycosylphosphatidylinositol (GPI) anchor synthesis. Impaired Pigp expression in Wbp7-/- macrophages abolished GPI anchor-dependent loading of proteins on the cell membrane. Consistently, loss of GPI-anchored CD14, the coreceptor for lipopolysaccharide (LPS)
The histone methyltransferase Wbp7 controls macrophage function through GPI glycolipid anchor synthesis.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
CD14 regulates the dendritic cell life cycle after LPS exposure through NFAT activation.
Specimen part
View SamplesInterleukin-2 (IL-2) is one of the molecules produced by mouse dendritic cells (DCs) after stimulation by Toll like receptor (TLR) agonists. By analogy with the events following T-cell receptor (TCR) engagement leading to IL-2 production we have observed that DC stimulation with lipopolysaccharide (LPS) induces Src-family kinase and phospholipase C (PLC)2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. We have also observed that the initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. To determine the role of NFAT in LPS activated dendritic cells we have performed microarray analysis in conditions allowing or inhibiting NFAT activation. We show here that LPS-induced NFAT activation via CD14 is necessary to cause death of terminally differentiated DCs, an event that is essential for maintaining self-tolerance and preventing autoimmunity. Consequently, blocking this pathway in vivo causes prolonged DC survival and an increase in T cell priming capability.
CD14 regulates the dendritic cell life cycle after LPS exposure through NFAT activation.
Specimen part
View SamplesDendritic cells (DCs) are a special class of leukocytes able to activate both innate and adaptive immune responses. They interact with microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize molecular patterns expressed by various microorganisms. Upon antigen binding, PRRs instruct DCs for the appropriate priming of natural killer cells, followed by specific T-cell responses. Once completed the effector phase, DCs reach the terminal differentiation stage and eventually die by apoptosis. We have observed that following lipopolysaccharide (LPS)-stimulation the initiation of the apoptotic pathway in DCs is due the activation of NFAT proteins. Indeed, LPS induces Src-family kinase and phospholipase C (PLC)2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. The initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. According with this observation CD14-deficient DCs do not die following LPS stimulation. Nevertheless, CD14-deficient DC death following LPS activation can be restored by co-stimulating DCs with LPS and thapsigargin. Thapsigargin empties the intracellular calcium stores by blocking calcium pumping into the sarcoplasmic and endoplasmic reticulum and thereby activates plasma membrane calcium channels. This, in turn, allows an influx of calcium into the cytosol and NFAT activation. To identify the NFAT controlled apoptosis genes in LPS activated DCs we have performed a kinetic microarray analysis (0, 48 and 60 h) in conditions allowing or inhibiting NFAT activation. Four genes have been selected: Nur77, Gadd45g, Ddit3/Gadd153/Chop-10 and Tia1.
CD14 regulates the dendritic cell life cycle after LPS exposure through NFAT activation.
Specimen part
View SamplesMacrophages and dendritic cells (DCs) differently contribute to the generation of coordinated immune system responses against infectious agents. They interact with microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize molecular patterns expressed by various microorganisms. Upon antigen binding, PRRs instruct DCs for the appropriate priming of natural killer cells, followed by specific T-cell responses. Once completed the effector phase, DCs reach the terminal differentiation stage and eventually die by apoptosis. By contrast, following antigen recognition, macrophages initiate first the inflammatory process and then switch to an anti-inflammatory phenotype for the restoration of tissue homeostasis. Following lipopolysaccharide (LPS)-stimulation the initiation of the apoptotic pathway in DCs is due the activation of NFAT proteins. DC stimulation with lipopolysaccharide (LPS) induces Src-family kinase and phospholipase C (PLC)2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. The initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. We asked whether macrophage survival after LPS encounter was due to their inability to activate the Ca2+ pathway.
CD14 regulates the dendritic cell life cycle after LPS exposure through NFAT activation.
Specimen part
View SamplesWe investigated the molecular mechanisms of chronic alcohol consumption or lipopolysaccharide insult by gene expression profiling in prefrontal cortex and liver of C57BL/6J mice.
Gene expression in brain and liver produced by three different regimens of alcohol consumption in mice: comparison with immune activation.
Age, Specimen part
View SamplesProduction of functional proteins requires multiple steps including gene transcription and post-translational processing. MicroRNAs (miRNA) can regulate individual stages of these processes. Despite the importance of the cystic fibrosis transmembrane conductance regulator (CFTR) channel for epithelial anion transport, how its expression is regulated remains uncertain. We discovered that microRNA-138 regulates CFTR expression through its interactions with the transcriptional regulatory protein SIN3A. Treating airway epithelia with a miR-138 mimic increased CFTR mRNA and also enhanced CFTR abundance and transepithelial Cl- permeability independently of elevated mRNA levels. A miR-138 anti-miR had the opposite effects. Importantly, miR-138 altered the expression of many genes encoding proteins that associate with CFTR and may influence its biosynthesis. The most common CFTR mutation, F508, causes protein misfolding, degradation, and cystic fibrosis. Remarkably, manipulating the miR-138 regulatory network also improved biosynthesis of CFTR-F508 and restored Cl- transport to cystic fibrosis airway epithelia. This novel miRNA-regulated network directs gene expression from the chromosome to the cell membrane, indicating that an individual miRNA can control a cellular process broader than previously recognized. This discovery also provides new therapeutic avenues for restoring CFTR function to cells affected by the most common cystic fibrosis mutation.
A microRNA network regulates expression and biosynthesis of wild-type and DeltaF508 mutant cystic fibrosis transmembrane conductance regulator.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A high protein diet during pregnancy affects hepatic gene expression of energy sensing pathways along ontogenesis in a porcine model.
Specimen part
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